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  • 1.
    Atefi, Seyed Reza
    et al.
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Electrical Bioimpedance cerebral monitoring. Preliminary results from measurements on stroke patients2012In: Engineering in Medicine and Biology Society (EMBC), 2012 Annual International Conference of the IEEE, IEEE , 2012, p. 126-129Conference paper (Refereed)
    Abstract [en]

    Electrical Bioimpedance Spectroscopy (EBIS) is currently used in different tissue characterization applications. In this work we aim to use EBIS to study changes in electrical properties of the cerebral tissues after an incident of hemorrhage/ischemic stroke. To do so a case-control study was conducted using six controls and three stroke cases. The preliminary results of this study show that by using Cole-based analysis on EBIS measurements and analyzing the Cole parameters R0 and R∞, it is possible to detect changes on electrical properties of cerebral tissue after stroke. 

  • 2.
    Ban, Yifang
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Fredman, David
    Jonsson, Martin
    Svensson, Leif
    Multi-Criteria Evaluations for Improved Placement of Defibrillators: Preliminary Results2013In: Circulation, ISSN 0009-7322, E-ISSN 1524-4539, Vol. 128, no 22, p. 78-Article in journal (Other academic)
  • 3.
    Broome, M.
    Karolinska Institutet.
    Simulation of cardiovascular physiology and pathology: The effects of mitral regurgitation on venous pulmonary flow and mitral flow.2003Other (Refereed)
    Abstract [en]

    Background: The development of simulation models and modern computers makes it possible to simulate both normal cardiovascular physiology and pathology realistically. These models can be used to aid clinicians and researchers in understanding complex phenomenon. Methods: An electrical analogue of the cardiovascular system consisting of resistances, capacitances and inductances has been constructed. The contractile function of the cardiac atria and ventricles area represented by time-varying elastances. Valvular function, pericardial volume, ventricular interaction and intrathoracic pressure are also represented by constants and functions interacting with the rest of the model. Results: A regurgitant mitral orifice of 1 cm2 during systole results in an increased volume load on the left ventricle, a decrease in cardiac output and systemic arterial blood pressures accompanied by an increase in left and right-sided cardiac filling pressures and volumes. More specifically a systolic reversal of flow in the pulmonary veins is seen. Conclusion: Simulation of cardiac normal function and pathology is a meaningful way to study the heart. Results from simulations can be used to interpret clinical invasive monitoring and echocardiography data as well as experimental research data.

  • 4.
    Broome, Michael
    KTH, School of Technology and Health (STH), Medical Engineering.
    Aplysia CorVascSim2012Other (Other academic)
  • 5.
    Broome, Michael
    Karolinska Institutet.
    MEDIQ CorVascSim2011Other (Other academic)
  • 6.
    Broome, Michael
    Karolinska Institutet.
    Simulation of Cardiovascular Physiology and Pathology: The Effects of Mitral Regurgitation on Mitral and Pulmonary Venous Flow2004Other (Other academic)
    Abstract [en]

    Background: The development of simulation models and modern computers makes it possible to simulate both normal cardiovascular physiology and pathology realistically. These models can be used to aid clinicians and researchers in understanding complex phenomenon. Methods: An electrical analogue of the cardiovascular system consisting of resistances, capacitances and inductances has been constructed. The contractile function of the cardiac atria and ventricles area represented by time-varying elastances. Valvular function, pericardial volume, ventricular interaction and intrathoracic pressure are also represented by constants and functions interacting with the rest of the model. Results: A regurgitant mitral orifice of 1 cm2 during systole results in an increased volume load on the left ventricle, a decrease in cardiac output and systemic arterial blood pressures accompanied by an increase in left and right-sided cardiac filling pressures and volumes. A systolic reversal of flow in the pulmonary veins is seen. The magnitude of systolic flow reversal in the pulmonary veins is dependent on left atrial compliance. Conclusion: Simulation of cardiac normal function and pathology is a meaningful way to study the heart. Results from simulations can be used to interpret clinical invasive monitoring and echocardiography data as well as experimental research data. Left atrial compliance may be of importance for interpretation of pulmonary venous flow profiles in mitral regurgitation.

  • 7.
    Broome, Michael
    Karolinska Institutet.
    Simulation of cardiovascular physiology and pathology with CorVascSim: A PC software for advanced education and research2004Other (Other academic)
    Abstract [en]

    Background and Goal: The rapid development of computer technology makes simulation of cardiovascular physiology and pathology possible. The current work presents a scientifically based cardiovascular model, with a self-explanatory interface. Material and Methods: An electrical analogue of the cardiovascular system including resistances, capacitances and inductances was constructed. The contractile function of the cardiac atria and ventricles are represented by time-varying elastances. Valvular function, pericardial volume, ventricular interaction and intrathoracic pressure are represented by constants and functions, which can interact. Pressures, flows and volumes are recalculated every millisecond and presented on-line as numerical and high-resolution graphics. Results and Discussion: The validity of the simulation models is based on the references (1-4). The software makes it possible to illustrate a great diversity of circulatory pathological findings including systolic and diastolic heart failure, valve diseases, pericardial effusion, arteriosclerosis and effects of changes in intrathoracic pressure. The model is being used to educate doctors and nurses in cardiac surgery, cardiac anaesthesia, and cardiology, but its pedagogical value remains to be validated. Conclusion: Simulation of cardiac physiology and pathology provides a new way to study the heart. Results from simulations can be used in education as well as in interpretation of clinical invasive monitoring, echocardiography and experimental research.

  • 8.
    Broome, Michael
    Karolinska Institutet.
    The Effects of Mitral Regurgitation on Venous Pulmonary Flow and Mitral Flow2004Other (Other academic)
  • 9. Bruzelius, M.
    et al.
    Bottai, M.
    Sabater-Lleal, M.
    Strawbridge, R. J.
    Bergendal, A.
    Silveira, A.
    Sundstrom, A.
    Kieler, H.
    Hamsten, A.
    Odeberg, Jacob
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab. Karolinska University Hospital Solna, Sweden; Karolinska Institutet, Sweden .
    Predicting venous thrombosis in women using a combination of genetic markers and clinical risk factors2015In: Journal of Thrombosis and Haemostasis, ISSN 1538-7933, E-ISSN 1538-7836, Vol. 13, no 2, p. 219-227Article in journal (Refereed)
    Abstract [en]

    BackgroundFamily history of venous thromboembolism (VTE) has been suggested to be more useful in risk assessment than thrombophilia testing. ObjectivesWe investigated established genetic susceptibility variants for association with VTE and evaluated a genetic risk score in isolation and combined with known trigger factors, including family history of VTE. Patients/MethodA total of 18 single nucleotide polymorphisms (SNPs) selected from the literature were genotyped in 2835 women participating in a Swedish nationwide case-control study (the ThromboEmbolism Hormone Study [TEHS]). Association with VTE was assessed by odds ratios (ORs) with 95% confidence interval (CI) using logistic regression. Clinical and genetic predictors that contributed significantly to the fit of the logistic regression model were included in the prediction models. SNP-SNP interactions were investigated and incorporated into the models if found significant. Risk scores were evaluated by calculating the area under the receiver-operating characteristics curve (AUC). ResultsSeven SNPs (F5 rs6025, F2 rs1799963, ABO rs514659, FGG rs2066865, F11 rs2289252, PROC rs1799810 and KNG1 rs710446) with four SNP-SNP interactions contributed to the genetic risk score for VTE, with an AUC of 0.66 (95% CI, 0.64-0.68). After adding clinical risk factors, which included family history of VTE, the AUC reached 0.84 (95% CI, 0.82-0.85). The goodness of fit of the genetic and combined scores improved when significant SNP-SNP interaction terms were included. ConclusionPrediction of VTE in high-risk individuals was more accurate when a combination of clinical and genetic predictors with SNP-SNP interactions was included in a risk score.

  • 10.
    Eiken, Ola
    et al.
    KTH, School of Technology and Health (STH), Environmental Physiology.
    Kölegård, Roger
    KTH, School of Technology and Health (STH), Environmental Physiology.
    Repeated exposures to moderately increased intravascular pressure increases stiffness in human arteries and arterioles2011In: Journal of Hypertension, ISSN 0263-6352, E-ISSN 1473-5598, Vol. 29, no 10, p. 1963-1971Article in journal (Refereed)
    Abstract [en]

    The aim was to investigate whether repeated exposures to moderate pressure elevations in the blood vessels of the arms (pressure training; PT) affect pressure distension in arteries/arterioles of healthy subjects (n=11). PT and vascular pressure-distension determinations were conducted with the subject seated in a pressure chamber with one arm slipped through a hole in the chamber door. Increased intravascular pressure was accomplished by increasing chamber pressure. Before PT, one arm was investigated (control arm) during stepwise increases in chamber pressure to 180 mmHg. Artery diameter and flow were measured in the brachial artery using ultrasonography/Doppler techniques. Thereafter, the contralateral arm underwent a PT regimen consisting of three 40 min sessions/ week during 5 weeks. Chamber pressure was increased during PT from 65 mmHg during the first week to 105 mmHg during the last week. After PT, pressure-distension relationships were examined in both the trained arm and the control arm. Prior to and following PT, endothelium-dependent and endothelium-independent dilatations of the brachial artery were studied. PT reduced (p<0.01) arterial pressure distension by 46 ± 18%. Likewise, the pressure-induced increase in arterial flow was less pronounced after (350 ± 249%) compared with before (685 ± 216 %) PT. The PT-induced reductions in arterial/arteriolar pressure distension were reversed 5 weeks post-PT. Neither endothelium-dependent nor endothelium-independent arterial dilatation were affected by PT. It thus appears that the in vivo wall stiffness in arteries and arterioles increases markedly in response to intermittent, moderate increments of transmural pressure during 5 weeks. The increases in arterial/arteriolar stiffness are reversible and do not reflect a reduced capacity to dilate the vessels. The findings are compatible with the notion that local load serves as “ a prime mover” in the development of vascular changes in hypertension.

  • 11. Ekstrand, E. E.
    et al.
    Gustafsson, A. G.
    Norhammar, A. N.
    Näsman, Per N.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Ryden, L. R.
    Kjellstrom, B. K.
    Periodontal disease: A potential risk factor for myocardial infarction in younger women2016In: EUROPEAN HEART JOURNAL, ISSN 0195-668X, Vol. 37, p. 350-350Article in journal (Refereed)
  • 12.
    Elmstedt, Nina
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Lind, Britta
    KTH, School of Technology and Health (STH), Medical Engineering.
    Ferm-Widlund, K.
    Westgren, M.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Fetal heart contractile function and gestational age2012In: Cardiovascular Research, ISSN 0008-6363, E-ISSN 1755-3245, Vol. 93, p. S108-S108Article in journal (Other academic)
  • 13. Erhart, P.
    et al.
    Hyhlik-Dürr, A.
    Geisbüsch, P.
    Kotelis, D.
    Müller-Eschner, M.
    Gasser, Thomas Christian
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).
    von Tengg-Kobligk, H.
    Böckler, D.
    Finite Element Analysis in Asymptomatic, Symptomatic, and Ruptured Abdominal Aortic Aneurysms: In Search of New Rupture Risk Predictors2015In: European Journal of Vascular and Endovascular Surgery, ISSN 1078-5884, E-ISSN 1532-2165, Vol. 49, no 3, p. 239-245Article in journal (Refereed)
    Abstract [en]

    Objectives: To compare biomechanical rupture risk parameters of asymptomatic, symptomatic and ruptured abdominal aortic aneurysms (AAA) using finite element analysis (FEA). Study design: Retrospective biomechanical single center analysis of asymptomatic, symptomatic, and ruptured AAAs. Comparison of biomechanical parameters from FEA. Materials and methods: From 2011 to 2013 computed tomography angiography (CTA) data from 30 asymptomatic, 15 symptomatic, and 15 ruptured AAAs were collected consecutively. FEA was performed according to the successive steps of AAA vessel reconstruction, segmentation and finite element computation. Biomechanical parameters Peak Wall Rupture Risk Index (PWRI), Peak Wall Stress (PWS), and Rupture Risk Equivalent Diameter (RRED) were compared among the three subgroups. Results: PWRI differentiated between asymptomatic and symptomatic AAAs (p < .0004) better than PWS (p < .1453). PWRI-dependent RRED was higher in the symptomatic subgroup compared with the asymptomatic subgroup (p < .0004). Maximum AAA external diameters were comparable between the two groups (p < .1355). Ruptured AAAs showed the highest values for external diameter, total intraluminal thrombus volume, PWS, RRED, and PWRI compared with asymptomatic and symptomatic AAAs. In contrast with symptomatic and ruptured AAAs, none of the asymptomatic patients had a PWRI value >1.0. This threshold value might identify patients at imminent risk of rupture: Conclusions: From different FEA derived parameter, PWRI distinguishes most precisely between asymptomatic and symptomatic AAAs. If elevated, this value may represent a negative prognostic factor for asymptomatic AAAs.

  • 14.
    Forsell, Caroline
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Biomechanics.
    Björck, Hanna M.
    Eriksson, Per
    Franco-Cereceda, Anders
    Gasser, T. Christian
    KTH, School of Engineering Sciences (SCI), Mechanics, Biomechanics.
    Biomechanical Properties of the Thoracic Aneurysmal Wall: Differences Between Bicuspid Aortic Valve and Tricuspid Aortic Valve Patients2014In: Annals of Thoracic Surgery, ISSN 0003-4975, E-ISSN 1552-6259, Vol. 98, no 1, p. 65-71Article in journal (Refereed)
    Abstract [en]

    Background. The prevalence for thoracic aortic aneurysms (TAAs) is significantly increased in patients with a bicuspid aortic valve (BAV) compared with patients who have a normal tricuspid aortic valve (TAV). TAA rupture is a life-threatening event, and biomechanics-based simulations of the aorta may help to disentangle the molecular mechanism behind its development and progression. The present study used polarized microscopy and macroscopic in vitro tensile testing to explore collagen organization and mechanical properties of TAA wall specimens from BAV and TAV patients. Methods. Circumferential sections of aneurysmal aortic tissue from BAV and TAV patients were obtained during elective operations. The distribution of collagen orientation was captured by a Bingham distribution, and finite element models were used to estimate constitutive model parameters from experimental load-displacement curves. Results. Collagen orientation was almost identical in BAV and TAV patients, with a highest probability of alignment along the circumferential direction. The strength was almost two times higher in BAV samples (0.834 MPa) than in TAV samples (0.443 MPa; p < 0.001). The collagen-related stiffness (C-f) was significantly increased in BAV compared with TAV patients (C-f = 7.45 MPa vs 3.40 MPa; p = 0.003), whereas the elastin-related stiffness was similar in both groups. A trend toward a decreased wall thickness was seen in BAV patients (p = 0.058). Conclusions. The aneurysmal aortas of BAV patients show a higher macroscopic strength, mainly due to an increased collagen-related stiffness, compared with TAV patients. The increased wall stiffness in BAV patients may contribute to the higher prevalence for TAAs in this group.

  • 15.
    Gharehbaghi, Arash
    et al.
    Linkoping Univ, Dept Biomed Engn, Physiol Measurements, Linkoping, Sweden..
    Ekman, Inger
    Linkoping Univ, Fac Hlth Sci, Dept Med & Hlth Sci, Dept Clin Physiol, Linkoping, Sweden..
    Ask, Per
    Linkoping Univ, Dept Biomed Engn, Physiol Measurements, Linkoping, Sweden..
    Nylander, Eva
    Linkoping Univ, Fac Hlth Sci, Dept Med & Hlth Sci, Dept Clin Physiol, Linkoping, Sweden.;Linkoping Univ, Ctr Med Image Sci & Visualizat, Linkoping, Sweden..
    Janerot Sjöberg, Birgitta
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging. Karolinska Inst, Dept Clin Sci Intervent & Technol, Div Med Imaging & Technol, Stockholm, Sweden.;Karolinska Univ Hosp, Dept Clin Physiol, Stockholm, Sweden.;Karolinska Univ Hosp, Dept Med Technol, Stockholm, Sweden.;KTH Royal Inst Technol, Sch Technol & Hlth, Stockholm, Sweden..
    Assessment of aortic valve stenosis severity using intelligent phonocardiography2015In: International Journal of Cardiology, ISSN 0167-5273, E-ISSN 1874-1754, Vol. 198, p. 58-60Article in journal (Refereed)
  • 16.
    Govind, Satish C.
    et al.
    BMJ Heart Center, Bangalore, India.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Nowak, J.
    Karolinska Institute, Department of Clinical Physiology, Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Arvind, S. R.
    BMJ Heart Center, Bangalore, India.
    Ramesh, S. S.
    BMJ Heart Center, Bangalore, India.
    Netyö, A.
    Karolinska Institute, Department of Clinical Physiology, Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Prasad, K.Y.M.
    BMJ Heart Center, Bangalore, India.
    Saha, S.
    Karolinska Institute, Department of Clinical Physiology, Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Microalbuminuria and Left Ventricular Functions in Type 2 Diabetes: A Quantitative Assessment by Stress Echocardiography in the Myocardial Doppler in Diabetes (MYDID) Study III2007In: International Journal of Cardiology, ISSN 0167-5273, E-ISSN 1874-1754, Vol. 41, no 6, p. 363-369Article in journal (Refereed)
    Abstract [en]

    Background. Left ventricular (LV) function might be altered in type 2 diabetes (DM) and microalbuminuria (MA) may accentuate the abnormalities. We sought to investigate whether additional LV dysfunction could be unmasked using tissue Doppler (TVE)-enhanced dobutamine stress echocardiography (TVE-DSE) in patients with DM+MA. Methods. Twenty seven DM subjects with MA, (DM+MA), 31 DM subjects without MA (DM-MA), and 13 Controls were evaluated using TVE-DSE. LV basal peak systolic (PSV), early (E') and late (A') diastolic velocities (cm/sec) at rest and peak stress were post-processed. LV filling pressure was assessed using E/E'ratio. Results. PSV and E'velocity at peak stress in the respective three groups were 13.7±1.0, 10.1±1.1, 10.0±1.2 for PSV; and 10.0±1.6, 5.0±1.4, 4.8±1.4 for E' (p < 0.001 for controls vs. both groups). E/E' at rest was 7.9±0.7 in the controls, 10.8±2.4 in DM-MA, and 11.0±2.2 in DM+MA (p < 0.01 Controls vs. both the DM groups). Conclusions. Patients with DM+MA do not have additional LV regional systolic and diastolic dysfunctions compared with DM-MA, as revealed by TVE-DSE, when controlled for glycemia levels, lipids, and treatment strategies.

  • 17.
    Govind, Satish C.
    et al.
    BMJ Heart Center, Bangalore, India.
    Brodin, Lars-Åke
    Department of Clinical Physiology, Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Nowak, J.
    Department of Clinical Physiology, Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Quintana, M.
    Department of Clinical Physiology, Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Raumina, S.
    Department of Clinical Physiology, Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Ramesh, S.S.
    BMJ Heart Center, Bangalore, India.
    Keshava, R.
    BMJ Heart Center, Bangalore, India.
    Saha, S.
    Department of Clinical Physiology, Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Isolated Type 2 Diabetes mellitus Causes Myocardial Dysfunction That Becomes Worse in the Presence of Cardiovascular Diseases: Results of the Myocardial Doppler in Diabetes (MYDID): Study 12005In: Cardiology, ISSN 0008-6312, E-ISSN 1421-9751, Vol. 103, no 4, p. 189-195Article in journal (Refereed)
    Abstract [en]

    Aims: Patients with type 2 diabetes mellitus (DM) often suffer disproportionately and have a worse outcome when burdened with cardiovascular complications compared with those without DM. A specific heart muscle disease reportedly caused by DM per se may explain this. We sought to investigate whether an echo Doppler diagnosis of such a myocardial disease is clinically relevant in DM with or without coexistent coronary artery disease (CAD) and/or hypertension ( HTN). Subjects and Methods: Two hundred subjects (127 males, 73 females, 56 +/- 10 years) including controls (n=23), patients with HTN (n=20), CAD (n=35), uncomplicated DM (n=59), DM+HTN (n=27), DM+ CAD (n=16) and DM+CAD+HTN (n=20) underwent tissue Doppler-enhanced dobutamine stress echocardiography. Myocardial function was assessed by measuring left ventricular myocardial peak systolic velocity (PSV) and early diastolic velocity at rest and during peak stress, besides measurements of standard Doppler variables. Results: Average left ventricular PSV at rest was significantly lower in CAD (4.7 +/- 1.5) compared with controls (5.7 center dot +/- 1.2) and in DM+CAD+HTN (4.6 +/- 1.4) compared with DM (5.6 +/- 1.3; all p < 0.05). During peak stress, lower PSV persisted in CAD (9.5 +/- 3.1) and DM+CAD+HTN (8.1 +/- 2.7), while appearing de novo in DM (11.3 +/- 2.6) and HTN (11.0 +/- 2.3) unlike in the controls (12.5 +/- 2.5; all p < 0.001). When pooled together, DM subjects with CAD and/or HTN or both had significantly lower PSV (9.1 +/- 2.7) than those without (10.0 +/- 2.8; p < 0.001). Early diastolic velocity response was equally lower in both groups compared with the controls. Conclusion: The results suggest that dobutamine stress unmasks myocardial functional disturbances caused by uncomplicated DM. The discrete disturbances become quantitatively more pronounced in the presence of coexistent cardiovascular diseases.

  • 18.
    Govind, Satish C.
    et al.
    BMJ Heart Center, Department of Non-invasive Cardiology, Bangalore, India.
    Brodin, Lars-Åke
    Department of Clinical Physiology, Karolinska University Hospital at Huddinge.
    Nowak, J.
    BMJ Heart Center, Department of Non-invasive Cardiology, Bangalore, India.
    Ramesh, S. S.
    BMJ Heart Center, Department of Non-invasive Cardiology, Bangalore, India.
    Saha, S. K.
    Department of Clinical Physiology, Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Acute administration of a single dose of valsartan improves left ventricular functions: a pilot study to assess the role of tissue velocity echocardiography in patients with systemic arterial hypertension in the TVE-valsartan study I2006In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 26, no 6, p. 351-356Article in journal (Refereed)
    Abstract [en]

    Background The advent of colour-coded tissue velocity echocardiography (TVE) has now made it possible to quantify left ventricular (LV) functions in patients with systemic arterial hypertension (HTN).

    Hypothesis In this project, we have studied the cardiac effects of a single dose of orally administered valsartan in patients with known HTN.

    Methods Fifty-five patients with HTN with a mean age of 56 +/- 10 years were given an early morning dose of 80 mg valsartan withholding regular antihypertensive medications on the day of investigation. TVE images, acquired on VIVID systems were digitized for postprocessing of longitudinal and radial peak systolic velocities, strain rate, and systolic and diastolic time intervals before (pre) and 5 h after (post) administration of the drug.

    Results Blood pressure (mmHg) pre and post, respectively, were 147 +/- 15 versus 137 +/- 14 systolic and 90 +/- 7 versus 86 +/- 7 diastolic (all P < 0.01). LV longitudinal systolic velocities (cm s(-1)) were significantly higher post in LV septum (5.7 +/- 1.1 versus 6.4 +/- 1.6; P < 0.001) with similar results obtained in other LV walls. Radial strain rate (1 s(-1)) was significantly higher post compared with pre valsartan (2.1 +/- 0.6 versus 2.3 +/- 0.9; P < 0.01). Regional diastolic filling and ejection times (ms) were significantly shorter post (390 +/- 122 versus 370 +/- 120 and 275 +/- 32 versus 163 +/- 36 respectively; all P < 0.05).

    Conclusions Within 5 h after oral administration of valsartan, improvement in regional myocardial systolic functions could be registered. Although the changes could well be secondary to afterload reduction, additional effects of the drug, evidenced by improved strain rate that is relatively load-independent, may have contributed in this improvement.

  • 19.
    Govind, Satish C.
    et al.
    Bhagwan Mahavir Jain Heart Center, Bangalore, India.
    Roumina, S.
    Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Nowak, J.
    Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Ramesh, S. S.
    Bhagwan Mahavir Jain Heart Center, Bangalore, India.
    Saha, S. K.
    Karolinska University Hospital at Huddinge, Stockholm, Sweden.
    Differing myocardial response to a single session of hemodialysis in end-stage renal disease with and without type 2 diabetes mellitus and coronary artery disease2006In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 4, no 9Article in journal (Refereed)
    Abstract [en]

    Background: Though hemodialysis (HD) acutely improves cardiac function, the impact of background diseases like coronary artery disease (CAD) and Type 2 diabetes (DM) in the setting of end-stage renal disease (ESRD) is not known. Tissue velocity echocardiography (TVE) offers a fast choice to follow changes in myocardial function after HD in ESRD with concomitant DM and/or CAD. Methods: 46 subjects (17 with ESRD, Group 1; 15 with DM, Group 2; 14 with DM+CAD, Group 3) underwent standard and TVE prior to and shortly after HD. Besides standard Doppler variables, regional myocardial systolic and diastolic velocities, as well as systolic strain rate were post processed. Results: Compared with pre-HD, post-HD body weight (kg) significantly decreased in all the three groups (51 ± 9 vs. 48 ± 8, 62 ± 10 vs.59 ± 10, and 61 ± 9 vs. 58 ± 9 respectively; all p < 0.01). Left ventricular end diastolic dimensions (mm) also decreased post- HD (46 ± 5 vs. 42 ± 7, 53 ± 7 vs. 50 ± 7, 51 ± 7 vs. 47 ± 8 respectively; all p < 0.01). Regional longitudinal peak systolic velocity in septum (cm/s) significantly increased post-HD in Group 1(5.7 ± 1.6 vs. 7.2 ± 2.3; p < 0.001) while remained unchanged in the other two groups. Similar trends were noted in other left ventricular walls. When the myocardial velocities (cm/s) were computed globally, the improvement was seen only in Group 1 (6.3 ± 1.5 vs. 7.9 ± 2.0; p < 0.001). Global early regional diastolic velocity (cm/s) improved in Group 1, remained unchanged in Group 2, while significantly decreased in Group 3(-5.9 ± 1.3 vs. -4.1 ± 1.8; p < 0.01). Global systolic strain rate (1/sec) increased in the first 2 Groups but remained unchanged (-0.87 ± 0.4 vs. -0.94 ± 0.3; p = ns) in Group 3. Conclusion: A single HD session improves LV function only in ESRD without coexistent DM and/or CAD. The present data suggest that not only dialysis-dependent changes in loading conditions but also co-existent background diseases determine the myocardial response to HD.

  • 20.
    Govind, Satish C.
    et al.
    Department of Clinical Physiology, Karolinska Institute, Karolinska University Hospital, Huddinge, Stockholm, Sweden.
    Saha, S.
    Department of Clinical Physiology, Karolinska Institute, Karolinska University Hospital, Huddinge, Stockholm, Sweden.
    Brodin, Lars-Åke
    Department of Clinical Physiology, Karolinska Institute, Karolinska University Hospital, Huddinge.
    Ramesh, S. S.
    BMJ Heart Center, Bangalore, India.
    Arvind, S. R.
    BMJ Heart Center, Bangalore, India.
    Quintana, M.
    Department of Clinical Physiology, Karolinska Institute, Karolinska University Hospital, Huddinge, Stockholm, Sweden.
    Impaired Myocardial Functional Reserve in Hypertension and Diabetes Mellitus Without Coronary Artery Disease: Searching for the Possible Link With Congestive Heart Failure in the Myocardial Doppler in Diabetes (MYDID) Study II2006In: American Journal of Hypertension, ISSN 0895-7061, E-ISSN 1941-7225, Vol. 19, no 8, p. 851-857Article in journal (Refereed)
    Abstract [en]

    Background: Although the impact of type 2 diabetes mellitus (DM) and hypertension (HTN) on myocardial function has recently been studied using tissue Doppler echocardiography (TDE), the independent role of both conditions, and the influence of other risk factors on myocardial function has not been completely defined, particularly in absence of coronary artery disease (CAD). The aim of this study was to assess the myocardial functional reserve in patients with DM or HTN with apparently normal left ventricular (LV) systolic function.

    Methods: Standard and dobutamine stress echocardiography using TDE was performed in 128 subjects: 59 had DM, 20 had HTN, 27 had both DM and HTN (HTN + DM), and 22 subjects were controls (C). Subjects with known CAD and depressed LV function were excluded. In addition, standard two-dimensional and Doppler measurements, LV regional peak systolic (PSV), early (E') and late (A') diastolic velocities, strain (S%) and strain rate (SR), were assessed at rest and peak stress.

    Results: The LV mass did not differ, although relative wall thickness was significantly higher in subjects with HTN + DM and HTN. The PSV did not differ at rest but was lowest in subjects with HTN + DM at peak stress. The E' wave velocity was significantly lower in subjects with HTN + DM both at rest and during peak stress, as were S% and SR.

    Conclusions: The addition of DM to HTN has a negative effect on LV systolic and diastolic functions. A depressed myocardial functional reserve might be postulated as one of the pathophysiologic mechanisms for the excessive occurrence of congestive heart failure in patients with DM or HTN.

  • 21.
    Grishenkov, Dmitry
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Polymer-shelled Ultrasound Contrast Agents: Characterization and Application2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Ultrasound-based imaging technique is probably the most used approach for rapid investigationand monitoring of anatomical and physiological conditions of internal organs and tissues.Ultrasound-based techniques do not require the use of ionizing radiation making the tests anexceptionally safe and painless. Operating in the frequency range between 1 to 15 MHz, medicalultrasound provides reliable visual and quantitative information from both superficial structuressuch as muscles and tendons, and also deeper organs such as liver and kidney. From the technicalpoint of view medical ultrasound has a good spatial and temporal resolution. Ultrasound machineis mobile or even portable, which makes it truly bedside modality. And last but not the least,ultrasound investigations are cheaper in comparison to other real time imaging techniques.

    Ultrasound imaging techniques can be greatly improved by the use of contrast agents to enhancethe signal from the area of interest (e.g. cardiac or liver tissues) relative to the background.Typically ultrasound contrast agent (UCA) is a suspension of the microbubbles consisting of agas core encapsulated within the solid shell. Generally these devices are injected systemically andfunction to passively enhance the ultrasound echo. In recent years, the UCAs have evolved frombeing just a visualization tool to become a new multifunctional and complex device for drug orgene therapy and targeted imaging.

    The overall objective of the project is to test novel polymer shelled microbubbles (MBs) as apossible new generation of ultrasound contrast agents.

    During the first year of the project an innovative criterion based on cross-correlation analysis toassess the pressure threshold at which ultrasonic waves fracture the polymer shell of microbubblehas been developed. In addition, acoustic properties of these microbubbles which are relevant totheir use both as contrast agents and drug carriers for localized delivery have been preliminarytested. Furthermore, in order to reconstruct viscoelastic properties of the shell the originalChurch’s model (1995) has been implemented. In collaboration with Karolinska Institutet, imagesof the microbubbles have been acquired with conventional imaging system. These imagesdemonstrate the potential of the novel polymer-shelled microbubbles to be used as contractenhancing agents.

    The objective of the second year was to describe the acoustic and mechanical properties ofdifferent types of microbubbles synthesised under varied conditions. This task was divided in twointerrelated parts. In the first part acoustic characterization has been completed in low intensityregion with the study of backscattered power, attenuation and phase velocity. In order torecalculate mechanical properties of the shell existing theoretical model has been furtheriimodified to accommodate the frequency dependence of viscoelastic properties andsimultaneously fit the attenuation and phase velocity data. The results concerning acoustic andmechanical properties of the microbubbles have been sent as a feedback to the manufacture inorder to optimize fabrication protocol for effective image acquisition. In the second part acousticcharacterization has been performed in high intensity region under varied parameters ofexperimental set-up. The results that illustrate the dependence of the fracture pressure thresholdon the system parameters allows us to discuss the potential role of polymer-shelled UCAs as drugcarriers and formulate the protocol for save, localized, cavitation-mediated drug delivery.

    For the third year the major task was to move on from the bulk volume in vitro tests towards themicrocapillary study and even further to incorporate the microcapillary into the tissue mimickingultrasound phantom. The last study has the objective to take into account the wave propagationthrough tissue. And last but not the least, the application of the polymer-shelled microbubblesfor evaluation of perfusion characteristics, i.e. capillary volume and velocity of the flow, has beenperformed. Similar tests are carried out with commercially available phospholipid-shelled UCA.Using destruction/replenishment technique it is suggested that the novel polymer-shelledmicrobubbles have a potential for a more accurate perfusion evaluation compared to that ofcommercially available phospholipid-shelled UCA.

    In conclusion, proposed polymer-shelled gas-core microbubbles provide a viable system to beused among the next generation of ultrasound contrast agents, which facilitate not only imageenhancement relevant to diagnostics but also localized and specific drug delivery for non-invasivetherapy even in acute conditions.

  • 22.
    Grishenkov, Dmitry
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Ultrasound.
    Kari, Leif
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Brismar, Torkel B.
    Karolinska University Hospital.
    Paradossi, Gaio
    Università di Roma Tor Vergata.
    Acoustic properties of polymer-shelled ultrasound contrast agents. Bulk volume vs. microcapillary2009In: 16th International Congress on Sound and Vibration 2009, ICSV 2009, Krakow, 2009, p. 2515-2522Conference paper (Refereed)
    Abstract [en]

    The focus of contrast-enhanced ultrasound research has developed beyond detecting the blood pool to new areas such as perfusion imaging, drug and gene therapy, and targeted imaging. Polymer-shelled microbubbles are proposed as a new generation of ultrasound contrast agents (UCAs) which fulfil the requirements of these applications. With a shelf-life of several months and possibility to conjugate pharmacological molecules to their surface, these UCAs will allow not only to enhance the contrast of ultrasound images, but also to function as carriers of drugs to be delivered locally. In this study, the results of an experimental investigation of three types of UCAs stabilized by thick poly vinyl alcohol (PVA) shell are presented. These UCAs are synthesized from a PVA aqueous solution under varied pH values and temperature. The UCAs differ from each other in their average diameter, shell thickness and polydispersity. Knowledge of the peak negative pressure at which the solid shell fractures is paramount for a proper use of UCAs. Therefore, the dependence of this quantity on temperature and number of cycles in the incident pulse is examined. Much of the blood volume resides in the microcirculation, with capillaries playing a particularly important role in patho-physiology and drug delivery. In this sense in vitro characterization of the UCAs oscillation was moved from bulk volume to the capillary scale, where tissue-bubble interaction takes place. The main conclusion to be drawn from these results is that the shell of the UCAs begin to fracture at values of mechanical index (MI) approved for clinical applications. The fatigue, i.e. the accumulation of damage within the shell of the UCAs, is found to play an important role in fracturing the shell. Finally adhesion of the UCAs to the elastic wall is studied and correlated with estimates of the shell’s visco-elastic constants. Open questions arising from this comparison are briefly discussed.

  • 23.
    Hashemi, Nashmil
    et al.
    Danderyd Hosp, Unit Cardiol, Dept Clin Sci, Karolinska Inst, Stockholm, Sweden.;Capio St Gorans Hosp, Dept Clin Physiol, S-11281 Stockholm, Sweden..
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Hedman, Anders
    Soder Sjukhuset, Sect Cardiol, Dept Clin Sci, Karolinska Inst, Stockholm, Sweden..
    Samad, Bassem A.
    Danderyd Hosp, Unit Cardiol, Dept Clin Sci, Karolinska Inst, Stockholm, Sweden..
    Alam, Mahbubul
    Danderyd Hosp, Unit Cardiol, Dept Clin Sci, Karolinska Inst, Stockholm, Sweden..
    Improved right ventricular index of myocardial performance in the assessment of right ventricular function after coronary artery bypass grafting2018In: Interactive Cardiovascular and Thoracic Surgery, ISSN 1569-9293, E-ISSN 1569-9285, Vol. 26, no 5, p. 798-804Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: Decreased right ventricular (RV) longitudinal function following coronary artery bypass grafting (CABG), as assessed by tricuspid annular systolic excursion (TAPSE) and RV peak systolic velocity (RVS') is a known condition. We aimed to explore the feasibility of the right ventricular index of myocardial performance (RIMP) in the assessment of RV function after CABG at rest and during peak dobutamine stress echocardiography (DSE). METHODS: Forty-two patients indicated for CABG were included in this study. Coronary angiography, DSE and exercise bicycle test were performed within 6 weeks before and 3 months after CABG. The RIMP, RVS' and TAPSE at the lateral tricuspid annulus were also assessed. The results were presented as mean +/- standard deviation. RESULTS: The RIMP improved after CABG both at rest (0.45 +/- 0.11 before vs 0.38 +/- 0.08 after CABG, P= 0.013) and during DSE (0.75 +/- 0.23 vs 0.49 +/- 0.14, P < 0.001). TAPSE declined significantly when comparing the values from before CABG to after CABG both at rest (23.9 +/- 4.46 vs 14.6 +/- 3.67, P < 0.001) and during DSE (20.9 +/- 4.16 vs 11.9 +/- 3.60, P < 0.001). RVS' also decreased after CABG both at rest (11.9 +/- 2.40 vs 8.5 +/- 1.93, P < 0.001) and during DSE (15.6 +/- 4.30 vs 10.5 +/- 3.21, P <0.001). On the other hand, exercise capacity improved after CABG compared with baseline (128.4 +/- 40.12 W vs 142.1 +/- 46.73 W, P = 0.014). CONCLUSIONS: RIMP improved after CABG both at rest and during DSE. The reduction in TAPSE and RVS' after CABG indicate reduced regional mechanical RV function along the long axis rather than reduced global RV function.

  • 24.
    Hashemi, Nashmil
    et al.
    Karolinska Inst, Danderyd Univ Hosp, Dept Clin Sci, Unit Cardiol, Stockholm, Sweden.;Capio St Gorans Hosp, Dept Clin Physiol, Stockholm, Sweden..
    Johnson, Jonas
    KTH, School of Technology and Health (STH), Medical Engineering.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Gomes-Bernardes, Andrei A.
    Capio St Gorans Hosp, Dept Clin Physiol, Stockholm, Sweden..
    Sartipy, Ulrik
    Karolinska Univ Hosp, Heart & Vasc Theme, Stockholm, Sweden.;Karolinska Inst, Dept Mol Med & Surg, Stockholm, Sweden..
    Svenarud, Peter
    Karolinska Univ Hosp, Heart & Vasc Theme, Stockholm, Sweden.;Karolinska Inst, Dept Mol Med & Surg, Stockholm, Sweden..
    Dalen, Magnus
    Karolinska Univ Hosp, Heart & Vasc Theme, Stockholm, Sweden.;Karolinska Inst, Dept Mol Med & Surg, Stockholm, Sweden..
    Back, Magnus
    Karolinska Univ Hosp, Dept Cardiol, Stockholm, Sweden..
    Alam, Mahbubul
    Karolinska Inst, Danderyd Univ Hosp, Dept Clin Sci, Unit Cardiol, Stockholm, Sweden..
    Winter, Reidar
    Karolinska Inst, Danderyd Univ Hosp, Dept Clin Sci, Unit Cardiol, Stockholm, Sweden..
    Right ventricular mechanics and contractility after aortic valve replacement surgery: a randomised study comparing minimally invasive versus conventional approach2018In: Open heart, E-ISSN 2053-3624, Vol. 5, no 2, article id UNSP e000842Article in journal (Refereed)
    Abstract [en]

    Objective Minimally invasive aortic valve replacementsurgery (MIAVR) is an alternative surgical technique to conventional aortic valve replacement surgery (AVR) in selected patients. The randomised study Cardiac Function after Minimally Invasive Aortic Valve Implantation (CMILE) showed that right ventricular (RV) longitudinal function was reduced after both MIAVR and AVR, but the reduction was more pronounced following AVR. However, postoperative global RV function was equally impaired in both groups. The purpose of this study was to explore alterations in RV mechanics and contractility following MIAVR as compared with AVR. Methods A predefined post hoc analysis of CMILE consisting of 40 patients with severe aortic valve stenosis who were eligible for isolated surgical aortic valve replacement were randomised to MIAVR or AVR. RV function was assessed by echocardiography prior to surgery and 40 days post-surgery. Results Comparing preoperative to postoperative values, RV longitudinal strain rate was preserved following MIAVR (-1.5 +/- 0.5 vs -1.5 +/- 0.4 1/s, p=0.84) but declined following AVR (-1.7 +/- 0.3 vs -1.4 +/- 0.3 its, p<0.01). RV longitudinal strain reduced following AVR (-27.4 +/- 2.9% vs -18.8%+/- 4.7%, p<0.001) and MIAVR (-26.5 +/- 5.3% vs -20.7%+/- 4.5%, p<0.01). Peak systolic velocity of the lateral tricuspid annulus reduced by 36.6% in the AVR group (9.3 +/- 2.1 vs 5.9 +/- 1.5 cm/s, p<0.01) and 18.8% in the MIAVR group (10.1 +/- 2.9 vs 8.2 +/- 1.4 cm/s, p<0.01) when comparing preoperative values with postoperative values. Conclusions RV contractility was preserved following MIAVR but was deteriorated following AVR. RV longitudinal function reduced substantially following AVR. A decline in RV longitudinal function was also observed following MIAVR, however, to a much lesser extent.

  • 25. Herling, Lotta
    et al.
    Johnson, Jonas
    KTH, School of Technology and Health (STH), Medical Engineering.
    Ferm-Widlund, Kjerstin
    Lindgren, Peter
    Acharya, Ganesh
    Westgren, Magnus
    Automated analysis of color tissue Doppler velocity recordings of the fetal myocardium using a new algorithm2015In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 13, article id 39Article in journal (Refereed)
    Abstract [en]

    Background: Tissue Doppler imaging (TDI) can be used to assess fetal cardiac function and it has been shown to detect changes associated with hypoxia in animal models. However, the analysis is cumbersome and time consuming. The main objective of this study was to evaluate the feasibility of a new algorithm developed for the automated analysis of color TDI velocity recordings of the fetal myocardium. Furthermore, we wanted to assess the effect of different sizes of region of interests (ROI) on the measurement of cardiac cycle time intervals and myocardial velocities at different gestations. Methods: This study included analysis of 261 TDI velocity traces obtained from 17 fetal echocardiographic examinations performed longitudinally on five pregnant women. Cine-loops of fetal cardiac four chamber view were recorded with color overlay in TDI mode and stored for off-line analysis. ROIs of different sizes were placed at the level of the atrioventricular plane in the septum and in the right and left ventricular walls of the fetal heart. An automated algorithm was then used for the analysis of velocity traces. Results: Out of the total 261 velocity traces, it was possible to analyze 203 (78 %) traces with the automated algorithm. It was possible to analyze 93 % (81/87) of traces recorded from the right ventricular wall, 82 % (71/87) from the left ventricular wall and 59 % (51/87) from the septum. There was a trend towards decreasing myocardial velocities with increasing ROI length. However, the cardiac cycle time intervals were similar irrespective of which ROI size was used. Conclusions: An automated analysis of color TDI fetal myocardial velocity traces seems feasible, especially for measuring cardiac cycle time intervals, and has the potential for clinical application.

  • 26. Ivert, Torbjorn
    et al.
    Dalen, Magnus
    Ander, Charlotte
    Stalesen, Ragnhild
    Näsman, Per
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Lordkipanidze, Marie
    Hjemdahl, Paul
    Platelet function one and three months after coronary bypass surgery in relation to once or twice daily dosing of acetylsalicylic acid2017In: Thrombosis Research, ISSN 0049-3848, E-ISSN 1879-2472, Vol. 149, p. 64-69Article in journal (Refereed)
    Abstract [en]

    Introduction: Current guidelines recommend acetylsalicylic acid (ASA) treatment after coronary artery bypass grafting (CABG) to reduce thrombotic vein graft occlusion. The optimal dosage of ASA is not known. Materials and methods: Forty-two patients undergoing elective CABG were randomized to receive either ASA 75 mg or 160 mg once daily (OD) or 75 mg twice daily (BID) after the operation. Platelet function testing was performed before, and one and three months after the operation. Results: White blood cell counts increased during the initial postoperative days whereas platelet countswere initially slightly reduced after the operation but increased after one month without any major changes of mean platelet volumes. Serum thromboxane B-2 was more effectively suppressed at one and three months after the operation with ASA 75 mg BID or 160 mg OD than with 75 mg OD (p < 0.001). ASA 75 mg BID and 160 mg OD were equally effective. Adenosine diphosphate stimulated platelet aggregation in whole blood (Multiplate (R)) was increased one and three months after the operation, and this was counteracted by ASA 75 mg BID but not by 75 or 160 mg OD. Arachidonic acid-induced aggregation was more effectively inhibited by 75 mg BID or 160 mg OD compared to 75 mg OD at three months. Conclusions: Less effective inhibition of platelet activation was obtained with ASA 75 mg OD than with ASA 160mg OD or 75mg BID up to three months after CABG. Especially the latter dose is of interest for further studies of efficacy and clinical outcomes after CABG.

  • 27. Johansson, I.
    et al.
    Dahlström, U.
    Edner, M.
    Näsman, Per
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Ryden, L.
    Norhammar, A.
    Glycosylated haemoglobin predicts mortality in patients with heart failure and unknown diabetes: insights from the Swedish heart failure registry (SwedeHF)2016In: EUROPEAN HEART JOURNAL, ISSN 0195-668X, Vol. 37, p. 733-733Article in journal (Refereed)
  • 28. Johansson, I.
    et al.
    Edner, M.
    Näsman, Per
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Dahlstrom, U.
    Ryden, L.
    Norhammar, A.
    Impact of diabetes mellitus on heart failure with reduced ejection fraction: a Swedish registry based analysis2015In: European Heart Journal, ISSN 0195-668X, E-ISSN 1522-9645, Vol. 36, p. 877-877Article in journal (Other academic)
  • 29. Johansson, I.
    et al.
    Edner, M.
    Näsman, Per
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    Dahlström, U.
    Rydén, L.
    Norhammar, A.
    Impact of diabetes mellitus on long-term prognosis in patients with preserved heart failure - a report from the Swedish Heart Failure Registry (S-HFR)2014In: European Heart Journal, ISSN 0195-668X, E-ISSN 1522-9645, Vol. 35, p. 334-335Article in journal (Other academic)
  • 30. Johansson, Isabelle
    et al.
    Edner, Magnus
    Dahlström, Ulf
    Näsman, Per
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Rydén, Lars
    Norhammar, Anna
    Is the prognosis in patients with diabetes and heart failure a matter of unsatisfactory management?: An observational study from the Swedish Heart Failure Registry2014In: European Journal of Heart Failure, ISSN 1388-9842, E-ISSN 1879-0844, Vol. 16, no 4, p. 409-418Article in journal (Refereed)
    Abstract [en]

    Aims To analyse the long-term outcome, risk factor panorama, and treatment pattern in patients with heart failure (HF) with and without type 2 diabetes (T2DM) from a daily healthcare perspective. Methods and results Patients with (n = 8809) and without (n = 27 465) T2DM included in the Swedish Heart Failure Registry (S-HFR) 2003-2011 due to a physician-based HF diagnosis were prospectively followed for long-term mortality (median follow-up time: 1.9 years, range 0-8.7 years). Left ventricular function expressed as EF did not differ between patients with and without T2DM. Survival was significantly shorter in patients with T2DM, who had a median survival time of 3.5 years compared with 4.6 years (P < 0.0001). In subjects with T2DM. unadjusted and adjusted odds ratios (ORs) for mortality were 1.37 [95% confidence interval (CI) 1.30-1.44) and 1.60 (95% CI 1.50-1.71), and T2DM predicted mortality in all age groups. Ischaemic heart disease was an important predictor for mortality (OR 1.68, 95% CI 1.47-1.94), more abundant in patients with T2DM (59% vs. 45%) among whom only 35% had been subjected to coronary angiography and 32% to revascularization. Evidence-based pharmacological HF treatment was somewhat more extensive in patients with T2DM. Conclusion The combination of T2DM and HF seriously compromises long-term prognosis. Ischaemic heart disease was identified as one major contributor; however, underutilization of available diagnostic and therapeutic facilities for ischaemic heart disease was obvious and may be an important area for future improvement in patients with T2DM and HF.

  • 31. Järverud, Karin
    Correlation Between Hemodynamics And Dynamic Impedance At Constant Heart Rate2012Other (Refereed)
    Abstract [en]

    Introduction: Inappropriate ICD shocks are due to incorrect detection and discrimination based on IEGM and heart rate. Hemodynamic monitoring may be a useful function in ICDs. Dynamic cardiogenic impedance (CI) is the continuous (beat to beat) monitoring of cardiac function with the potential to provide hemodynamic monitoring. We hypothesized that impedance has additional benefits over heart rate in that CI carries more hemodynamical information than heart rate. To study this further, the correlation between varying hemodynamics and CI was examined in situations when heart rate change was eliminated. Methods: We analyzed CI data from 11 impedance configurations recorded in 8 anesthetized pigs receiving injections of Nitroprusside and Verapamil in sequence. Heart rate was maintained constant through either atrial pacing or DDD BiV pacing. Aortic and right ventricular blood pressure (AP and RVP) as well as arterial carotid and arterial femoral blood flow (ACF and AFF) was continuously recorded. Correlation was studied using cross-validated multivariate regression models with 10 features from single impedance configurations. Models were made across all subjects. Coefficients of determination (R2) were calculated. Significance was calculated using random permutation tests. Results:Drug injections successfully created a temporary drop by 30-50% in blood pressures and AFF in all 8 animals during which heart rate was successfully maintained at a constant level in each animal (110-130 BPM). The total number of heart beats analyzed was 12,913. Impedance based multivariate regression models successfully showed significant correlation between CI and blood pressures or flows; R2 = 0.91, p < 0.003 for mean AFF with RVtip-RVcoil bipolar CI; R2 = 0.85, p < 0.003 for max slope of AP with LV-RA bipolar CI; R2 = 0.94, p < 0.003 for min RVP with LV-RA bipolar CI. Conclusions:This prospective pre-clinical study has shown that there is a significant and strong correlation between dynamic cardiogenic impedance and hemodynamics during constant heart rate. It may ultimately provide true hemodynamic monitoring in ICDs.

  • 32. Kjellström, B.
    et al.
    Gustafsson, A.
    Nordendal, E.
    Norhammar, A.
    Nygren, Å.
    Näsman, Per
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. Center for Safety Research, Sweden.
    Rydén, L.
    Åsberg, M.
    Symptoms of depression and their relation to myocardial infarction and periodontitis2017In: European Journal of Cardiovascular Nursing, ISSN 1474-5151, E-ISSN 1873-1953, Vol. 16, no 6, p. 468-474Article in journal (Refereed)
    Abstract [en]

    Background: Psychosocial stress and depression are established risk factors for cardiovascular disease and a relationship to periodontitis has been suggested. We studied symptoms of depression and their relation to myocardial infarction and periodontitis. Methods: In a Swedish case-control study, 805 patients, <75 years with a first myocardial infarction and 805 controls without myocardial infarction were matched for age, gender and geographic area. Mean age was 62±8 years and 81% were male. Standardised physical examination and dental panoramic X-ray for grading of periodontal status was performed. Medical history including risk factors related to cardiovascular disease and periodontitis was collected as was detailed information on perceived stress at home and work, and symptoms of depression (Montgomery Åsberg Depression Scale). A Montgomery Åsberg Depression Scale score ≥13 was considered clinically relevant. Results: A family history of cardiovascular disease, smoking and divorce was more frequent among patients than controls. Patients had more symptoms of depression than controls (14 vs 7%; p<0.001) but received less anti-depressive treatment (16 vs 42%; p<0.001). Symptoms of depression doubled the risk for myocardial infarction (Montgomery Åsberg Depression Scale: odds ratio 2.17 (95% confidence interval 1.41-3.34)). There was no difference in symptoms of depression between study participants with and without periodontitis. Conclusion: Patients with a first myocardial infarction were more frequently depressed than matched controls without myocardial infarction, but received less anti-depressive treatment. A relationship between depression and periodontitis could not be confirmed.

  • 33. Lanzer, P.
    et al.
    Gijsen, F. J. H.
    Topoleski, L. D. T.
    Holzapfel, Gerhard A.
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.), Biomechanics.
    Call for Standards in Technical Documentation of Intracoronary Stents2010In: Herz, ISSN 0340-9937, E-ISSN 1615-6692, Vol. 35, no 1, p. 27-33Article, review/survey (Refereed)
    Abstract [en]

    At present, the product information of intracoronary stents provided by the industry contains only limited technical data restricting judgments on the in vivo performance of individual products. Available experimental and clinical evidence suggests that interventional target sites display highly heterogeneous biomechanical behavior needed to be matched by specific stent and stent delivery system characteristics. To allow individualized stent-lesion matching, both, understanding of biomechanical properties of the atherosclerotic coronary artery lesions and expert knowledge of the intracoronary stent systems, are required. Here, the authors review some of the initial data on mechanical properties of coronary artery lesions potentially relevant to stenting and suggest standards for technical documentation of intracoronary stents.

  • 34.
    Larsson, Malin K.
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Da Silva, Cristina
    Gunyeli, Elif
    Bin Ilami, Ali Akebat
    Szummer, Karolina
    Winter, Reidar
    KTH, School of Technology and Health (STH), Medical Engineering. Karolinska University Hospital, Sweden.
    Bjällmark, Anna
    KTH, School of Technology and Health (STH), Medical Engineering. Karolinska Institutet, Sweden.
    The potential clinical value of contrast-enhanced echocardiography beyond current recommendations2016In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 14, article id 2Article in journal (Refereed)
    Abstract [en]

    Background: Contrast agents are used in resting echocardiography to opacify the left ventricular (LV) cavity and to improve LV endocardial border delineation in patients with suboptimal image quality. If a wider use of contrast-enhanced echocardiography would be adopted instead of the current selective approach, diagnoses such as myocardial ischemia and LV structural abnormalities could potentially be detected earlier. The aim was therefore to retrospectively investigate if contrast- enhanced echocardiography beyond the current recommendations for contrast agent usage affects assessment of wall motion abnormalities, ejection fraction (EF) and detection of LV structural abnormalities. A secondary aim was to evaluate the user dependency during image analysis. Methods: Experienced readers (n = 4) evaluated wall motion score index (WMSI) and measured EF on greyscale and contrast-enhanced images from 192 patients without indications for contrast-enhanced echocardiography. Additionally, screening for LV structural abnormalities was performed. Repeated measurements were performed in 20 patients by the experienced as well as by inexperienced (n = 2) readers. Results: Contrast analysis resulted in significantly higher WMSI compared to greyscale analysis (p < 0.003). Of the 83 patients, classified as healthy by greyscale analysis, 55 % were re-classified with motion abnormalities by contrast analysis. No significant difference in EF classification (>= 55 %, 45-54 %, 30-44 %, < 30 %) was observed. LV structural abnormalities, such as increased trabeculation (n = 21), apical aneurysm (n = 4), hypertrophy (n = 1) and thrombus (n = 1) were detected during contrast analysis. Intra- and interobserver variability for experienced readers as well as the variability between inexperienced and experienced readers decreased for WMSI and EF after contrast analysis. Conclusions: Contrast-enhanced echocardiography beyond current recommendations for contrast agent usage increased the number of detected wall motion and LV structural abnormalities. Moreover, contrast- enhanced echocardiography increased reproducibility for assessment of WMSI and EF.

  • 35.
    Larsson, Malin K.
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Larsson, Matilda
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Nowak, Greg
    Paradossi, Gaio
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Janerot Sjöberg, Birgitta
    KTH, School of Technology and Health (STH), Medical Engineering.
    Caidahl, Kenneth
    Bjällmark, Anna
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Endocardial border delineation capability of a novel multimodal polymer-shelled contrast agent2014In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 12, p. 24-Article in journal (Refereed)
    Abstract [en]

    Background: A novel polymer-shelled contrast agent (CA) with multimodal and target-specific potential was developed recently. To determine its ultrasonic diagnostic features, we evaluated the endocardial border delineation as visualized in a porcine model and the concomitant effect on physiological variables. Methods: Three doses of the novel polymer-shelled CA (1.5 ml, 3 ml, and 5 ml [5 x 10(8) microbubbles (MBs)/ml]) and the commercially available CA SonoVue (1.5 ml [2-5 x 10(8) MBs/ml]) were used. Visual evaluations of ultrasound images of the left ventricle were independently performed by three observers who graded each segment in a 6-segment model as either 0 = not visible, 1 = weakly visible, or 2 = visible. Moreover, the duration of clinically useful contrast enhancement and the left ventricular opacification were determined. During anesthesia, oxygen saturation, heart rate, and arterial pressure were sampled every minute and the effect of injection of CA on these physiological variables was evaluated. Results: The highest dose of the polymer-shelled CA gave results comparable to SonoVue. Thus, no significant difference in the overall segment score distribution (2-47-95 vs. 1-39-104), time for clinically sufficient contrast enhancement (20-40 s for both) and left ventricular overall opacification was found. In contrast, when comparing the endocardial border delineation capacity for different regions SonoVue showed significantly higher segment scores for base and mid, except for the mid region when injecting 1.5 ml of the polymer-shelled CA. Neither high nor low doses of the polymer-shelled CA significantly affected the investigated physiological variables. Conclusions: This study demonstrated that the novel polymer-shelled CA can be used in contrast-enhanced diagnostic imaging without influence on major physiological variables.

  • 36.
    Larsson, Malin
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Larsson, Matilda
    KTH, School of Technology and Health (STH), Medical Engineering.
    Oddo, Letizia
    Margheritelli, Silvia
    Paradossi, Gaio
    Nowak, Jacek
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Caidahl, Kenneth
    Bjällmark, Anna
    KTH, School of Technology and Health (STH), Medical Engineering.
    Visualization of multimodal polymer-shelled contrast agents using ultrasound contrast sequences: an experimental study in a tissue mimicking flow phantom2013In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 11, p. 33-Article in journal (Refereed)
    Abstract [en]

    Background: A multimodal polymer-shelled contrast agent (CA) with target specific potential was recently developed and tested for its acoustic properties in a single element transducer setup. Since the developed polymeric CA has different chemical composition than the commercially available CAs, there is an interest to study its acoustic response when using clinical ultrasound systems. The aim of this study was therefore to investigate the acoustic response by studying the visualization capability and shadowing effect of three polymer-shelled CAs when using optimized sequences for contrast imaging. Methods: The acoustic response of three types of the multimodal CA was evaluated in a tissue mimicking flow phantom setup by measuring contrast to tissue ratio (CTR) and acoustic shadowing using five image sequences optimized for contrast imaging. The measurements were performed over a mechanical index (MI) range of 0.2-1.2 at three CA concentrations (10(6), 10(5), 10(4) microbubbles/ml). Results: The CTR-values were found to vary with the applied contrast sequence, MI and CA. The highest CTR-values were obtained when a contrast sequence optimized for higher MI imaging was used. At a CA concentration of 106 microbubbles/ml, acoustic shadowing was observed for all contrast sequences and CAs. Conclusions: The CAs showed the potential to enhance ultrasound images generated by available contrast sequences. A CA concentration of 106 MBs/ml implies a non-linear relation between MB concentration and image intensity.

  • 37. Li, Yanhong
    et al.
    Zelenina, Marina
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. Karolinska Institutet, Sweden.
    Plat-Willson, Genevieve
    Marcoux, Marie-Odile
    Aperia, Anita
    Casper, Charlotte
    Urinary aquaporin-2 excretion during ibuprofen or indomethacin treatment in preterm infants with patent ductus arteriosus2011In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 100, no 1, p. 59-66Article in journal (Refereed)
    Abstract [en]

    Aim: Water channel AQP2 is the target for vasopressin (AVP) and a major determinant of urinary concentrating capacity. In mature kidneys, prostaglandins counteract the effect of AVP on AQP2 expression at functional sites. We investigated whether disturbances in water homeostasis in infants with patent ductus arteriosus (PDA) treated with prostaglandin inhibitors can be attributed to activation of AQP2. Methods: In 53 infants with symptomatic PDA (gestational age 24-33 weeks), 30 receiving ibuprofen and 23 indomethacin starting at 2-15 days of life, clinical and biochemical data were collected before treatment and after each dose of the drugs. Urinary AQP2 was determined by dot immunoblotting. Results: Urinary AQP2 level and osmolality were decreased in both groups. Urinary osmolality was overall low and correlated inversely with fluid uptake. In ibuprofen group, there was no correlation of AQP2 level with urinary osmolality. Conclusion: There was no AQP2 upregulation in the infants. The low urinary osmolality and dissociation between urinary osmolality and urinary AQP2 level indicate that the fluid retention sometimes observed in PDA infants treated with prostaglandin inhibitors is not caused by increased levels of functional AQP2. Thus, knowledge about the renal physiology of the adult cannot always be transferred to the infant kidney.

  • 38. Liem, David A.
    et al.
    Nsair, Ali
    Setty, Shaun P.
    Cadeiras, Martin
    Wang, Ding
    Maclellan, Robb
    Lotz, Chris
    Lin, Amanda J.
    Tabaraki, Jason
    Li, Hua
    Ge, Junbo
    Odeberg, Jacob
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Pontén, Fredrik
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Larson, Erik
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Mulder, Jan
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Lundberg, Emma
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Weiss, James N.
    Uhlén, Mathias
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Ping, Peipei
    Deng, Mario C.
    Molecular- and Organelle-Based Predictive Paradigm Underlying Recovery by Left Ventricular Assist Device Support2014In: Circulation Heart Failure, ISSN 1941-3289, E-ISSN 1941-3297, Vol. 7, no 2, p. 359-366Article in journal (Refereed)
  • 39. Liljeqvist, Moritz Lindquist
    et al.
    Hultgren, Rebecka
    Siika, Antti
    Gasser, T. Christian
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).
    Roy, Joy
    Gender, smoking, body size, and aneurysm geometry influence the biomechanical rupture risk of abdominal aortic aneurysms as estimated by finite element analysis2017In: Journal of Vascular Surgery, ISSN 0741-5214, E-ISSN 1097-6809, Vol. 65, no 4, p. 1014-1021Article in journal (Refereed)
    Abstract [en]

    Objective: Finite element analysis (FEA) has been suggested to be superior to maximal diameter measurements in predicting rupture of abdominal aortic aneurysms (AAAs). Our objective was to investigate to what extent previously described rupture risk factors were associated with FEA-estimated rupture risk. Methods: One hundred forty-six patients with an asymptomatic AAA of a 40-to 60-mm diameter were retrospectively identified and consecutively included. The patients' computed tomography angiograms were analyzed by FEA without (neutral) and with (specific) input of patient-specific mean arterial pressure (MAP), gender, family history, and age. The maximal wall stress/wall strength ratio was described as a rupture risk equivalent diameter (RRED), which translated this ratio into an average aneurysm diameter of corresponding rupture risk. Results: In multivariate linear regression, RREDneutral increased with female gender (3.7 mm; 95% confidence interval [CI], 0.13-7.3) and correlated with patient height (0.27 mm/cm; 95% CI, 0.11-0.43) and body surface area (BSA, 16 mm/m(2); 95% CI, 8.3-24) and inversely with body mass index (BMI,-0.40 mm/kg m(-2); 95% CI, -0.75 to -0.054) in a wall stress-dependent manner. Wall stress-adjusted RREDneutral was raised if the patient was currently smoking (1.1 mm; 95% CI, 0.21-1.9). Age, MAP, family history, and patient weight were unrelated to RREDneutral. In specific FEA, RREDspecific increased with female gender, MAP, family history positive for AAA, height, and BSA, whereas it was inversely related to BMI. All results were independent of aneurysm diameter. Peak wall stress and RRED correlated with aneurysm diameter and lumen volume. Conclusions: Female gender, current smoking, increased patient height and BSA, and low BMI were found to increase the mechanical rupture risk of AAAs. Previously described rupture risk factors may in part be explained by patient characteristic-dependent variations in aneurysm biomechanics.

  • 40. Liljeqvist, Moritz Lindquist
    et al.
    Silveira, Angela
    Hultgren, Rebecka
    Frebelius, Siw
    Lengquist, Mariette
    Engström, Jan
    Gasser, T. Christian
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).
    Eriksson, Per
    Roy, Joy
    Neutrophil Elastase-Derived Fibrin Degradation Products Indicate Presence of Abdominal Aortic Aneurysms and Correlate with Intraluminal Thrombus Volume2018In: Thrombosis and Haemostasis, ISSN 0340-6245, Vol. 118, no 2, p. 329-339Article in journal (Refereed)
    Abstract [en]

    Background The intraluminal thrombi (ILT) of abdominal aortic aneurysms (AAA) contain neutrophils, which can secrete elastase. We evaluated whether plasma neutrophil elastase-derived cross-linked fibrin degradation products (E-XDP) could reveal the presence, size and mechanical stress of AAAs and its ILTs. Methods E-XDP and D-dimer were measured in plasma from 37 male patients with AAA and 42 male controls. The ILT volumes of the AAAs and any coexisting aneurysms could be measured in 29 patients and finite element analysis was performed to estimate mechanical stress of the ILT. E-XDP, neutrophil elastase and neutrophil marker CD66acd were evaluated in aortic tissue with immunohistochemistry (IHC). The association between ILT volume and E-XDP was validated in a separate cohort (n = 51). Results E-XDP levels were elevated in patients with AAA compared with controls (p = 5.8e-13), indicated AAA with 98% sensitivity, 86% specificity and increased with presence of coexisting aneurysms. The association between AAA and increased E-XDP was independent of smoking, comorbidities and medication. E-XDP correlated with volume of all ILTs (r = 0.76, p = 4.5e-06), mean ILTstress (r = 0.46, p = 0.013) and the volume of the AAA-associated ILT (r = 0.64, p = 0.00017). E-XDP correlated stronger with ILT volume compared with D-dimer (r = 0.76 vs. r = 0.64, p = 0.018). The correlation between E-XDP and ILT volume was validated in the separate cohort (r = 0.53, p = 7.6e-05). IHC revealed E-XDP expression in the ILT, spatially related to neutrophil elastase and neutrophils. Conclusion E-XDP is a marker of the presence of AAA and coexisting aneurysms as well as the volume and mechanical stress of the ILT.

  • 41. Lindfors, M.
    et al.
    Frenckner, B.
    Sartipy, U.
    Bjällmark, A.
    Broomé, Michael
    KTH, School of Technology and Health (STH), Medical Engineering.
    Venous Cannula Positioning in Arterial Deoxygenation During Veno-Arterial Extracorporeal Membrane Oxygenation-A Simulation Study and Case Report2016In: Artificial Organs, ISSN 0160-564X, E-ISSN 1525-1594Article in journal (Refereed)
    Abstract [en]

    Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is indicated in reversible life-threatening circulatory failure with or without respiratory failure. Arterial desaturation in the upper body is frequently seen in patients with peripheral arterial cannulation and severe respiratory failure. The importance of venous cannula positioning was explored in a computer simulation model and a clinical case was described. A closed-loop real-time simulation model has been developed including vascular segments, the heart with valves and pericardium. ECMO was simulated with a fixed flow pump and a selection of clinically relevant venous cannulation sites. A clinical case with no tidal volumes due to pneumonia and an arterial saturation of below 60% in the right hand despite VA-ECMO flow of 4 L/min was described. The case was compared with simulation data. Changing the venous cannulation site from the inferior to the superior caval vein increased arterial saturation in the right arm from below 60% to above 80% in the patient and from 64 to 81% in the simulation model without changing ECMO flow. The patient survived, was extubated and showed no signs of hypoxic damage. We conclude that venous drainage from the superior caval vein improves upper body arterial saturation during veno-arterial ECMO as compared with drainage solely from the inferior caval vein in patients with respiratory failure. The results from the simulation model are in agreement with the clinical scenario.

  • 42. Lindquist Liljeqvist, M.
    et al.
    Hultgren, R.
    Gasser, Christian
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.), Solid Mechanics (Div.).
    Roy, J.
    Volume growth of abdominal aortic aneurysms correlates with baseline volume and increasing finite element analysis-derived rupture risk2016In: Journal of Vascular Surgery, ISSN 0741-5214, E-ISSN 1097-6809, Vol. 63, no 6, p. 1434-1442Article in journal (Refereed)
    Abstract [en]

    Background: The diagnosis and management of abdominal aortic aneurysms (AAAs) currently relies on the aortic maximal diameter, which grows in an unpredictable manner. Infrarenal aortic volume has recently become clinically feasible to measure, and an estimate of biomechanical rupture risk derived from finite element analysis, the peak wall rupture index (PWRI), has been shown to predict AAA rupture. Our objective was to ascertain how well volume growth correlates with baseline volume and increasing PWRI, compared with the maximal diameter. Methods: We retrospectively identified 41 AAA patients (nine women, 32 men) at our institution who had undergone two computed tomography angiographies with an interval of 8 to 17 months. Digital three-dimensional reproductions of the aneurysms were segmented from the 82 computed tomography angiographies. AAA diameter, volume, and PWRI were measured and calculated with finite element analysis software. Growth rates of diameter and volume were related to baseline diameter and volume as well as to change rates of PWRI. Significant growth was defined as growth exceeding our interobserver 95% limits of agreement. Results: Diameter growth rate did not correlate with baseline diameter (r = 0.15, 95% confidence interval [CI], -0.17 to 0.45), but volume growth rate correlated with baseline volume (r = 0.56; 95% CI, 0.30-0.75). The correlation between baseline volume and volume growth rate was stronger than the correlation between baseline diameter and diameter growth rate (95% CI, 0.086-0.71). Increasing PWRI correlated with volume growth rate (r = 0.70; 95% CI, 0.40-0.87) but not with diameter growth rate (r = 0.044; 95% CI, -0.44 to 0.51), and the difference between the correlation coefficients was significant (95% CI, 0.11-1.16). Conclusions: Volume better predicts aneurysm growth rate and correlates stronger with increasing estimated biomechanical rupture risk compared with diameter. Our results support the notion of monitoring all three dimensions of an AAA.

  • 43. Majeed, Ammar
    et al.
    Agren, Anna
    Holmstrom, Margareta
    Bruzelius, Maria
    Chaireti, Roza
    Odeberg, Jacob
    Hempel, Eva-Lotta
    Magnusson, Maria
    Frisk, Tony
    Schulman, Sam
    Management of rivaroxaban- or apixaban-associated major bleeding with prothrombin complex concentrates: a cohort study2017In: Blood, ISSN 0006-4971, E-ISSN 1528-0020, Vol. 130, no 15, p. 1706-1712Article in journal (Refereed)
    Abstract [en]

    There is uncertainty regarding the effectiveness and occurrence of thromboembolic events in patients treated with prothrombin complex concentrates (PCCs) for the management of major bleeding events (MBEs) onrivaroxabanor apixaban. We investigated the effectiveness of PCCs given for the management of MBEs in patients on rivaroxaban or apixaban. Between 1 January 2014 and 1 October 2016, we prospectively included patients on rivaroxaban or apixaban treated with PCCs for the management of MBEs. The effectiveness of PCCs was assessed by using the International Society of Thrombosis and Hemostasis Scientific and Standardization Subcommittee criteria for the assessment of the effectiveness of major bleeding management. The safety outcomes were thromboembolic events and all-cause mortality with in 30 days after treatmentwith PCCs. Atotal of 84 patients received PCCs for the reversal of rivaroxaban or apixaban due to a MBE. PCCs were given at amedian (interquartile range) dose of 2000 IU (1500-2000 IU). Intracranial hemorrhage (ICH) was themost common site of bleeding requiring reversal (n = 5 59; 70.2%), followed by gastrointestinal bleeding in 13 (15.5%) patients. Management with PCCs was assessed as effective in 58 (69.1%) patients and ineffective in 26 (30.9%) patients. Most patients with ineffective hemostasis with PCCs had ICH (n 5 16; 61.5%). Two patients developed an ischemic stroke, occurring 5 and 10 days after treatment with PCC. Twenty seven (32%) patients died within 30 days after a MBE. The administration of PCCs for the management of MBEs associated with rivaroxaban or apixaban is effective inmost cases and is associated with a low risk of thromboembolism. Our findings are limited by the absence of a control group in the study.

  • 44.
    Manouchehrinia, Ali
    et al.
    Karolinska Inst, Karolinska Univ Hosp Solna, Dept Clin Neurosci, Stockholm, Sweden..
    Hedstrom, Anna Karin
    Karolinska Inst, Inst Environm Med, Unit Cardiovasc Epidemiol, Stockholm, Sweden..
    Alfredsson, Lars
    Karolinska Inst, Inst Environm Med, Unit Cardiovasc Epidemiol, Stockholm, Sweden.;Stockholm Cty Council, Ctr Occupat & Environm Med, Stockholm, Sweden..
    Olsson, Tomas
    Karolinska Inst, Karolinska Univ Hosp Solna, Dept Clin Neurosci, Stockholm, Sweden..
    Hillert, Jan
    Karolinska Inst, Karolinska Univ Hosp Solna, Dept Clin Neurosci, Stockholm, Sweden..
    Ramanujam, Ryan
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.). Karolinska Inst.
    Association of Pre-Disease Body Mass Index With Multiple Sclerosis Prognosis2018In: Frontiers in Neurology, ISSN 1664-2295, E-ISSN 1664-2295, Vol. 9, article id 232Article in journal (Refereed)
    Abstract [en]

    Both high body mass index (BMI) and smoking tobacco are known risk factors for developing multiple sclerosis (MS). However, it is unclear whether BMI, like smoking, is a risk factor for the secondary progressive (SP) course. We, therefore, sought to determine if high/low BMI at age 20 is associated to risk of SP development, in the context of smoking status. Using data from MS patients with BMI and smoking information available, we examined relapsing onset patients with MS onset after 20 years of age. Cox regressions were conducted on smokers and non-smokers, with BMI as the main exposure. In total, 5,598 relapsing onset MS patients were included. The models demonstrated that BMI > 30 was associated to increased risk of SPMS in smokers (hazard ratio 1.50, p = 0.036). This association of obesity at age 20 with increased risk of SP was not observed in non-smokers (hazard rate 0.97, p = 0.900). Since the risk is confined to smokers, the interaction observed may give insight to disease driving mechanisms.

  • 45. Manouras, A.
    et al.
    Nyktari, E.
    Sahlen, A.
    Winter, R.
    Vardas, P.
    Brodin, Lärs-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Evaluation of E/Em predictive capacity: Impact of acute load reduction2010In: European Heart Journal, ISSN 0195-668X, E-ISSN 1522-9645, Vol. 31, p. 733-733Article in journal (Refereed)
  • 46.
    Manouras, Aristomenis
    KTH, School of Technology and Health (STH), Medical Engineering.
    Tissue Doppler in Spectral and Color ModeMethodological ConsiderationsNon-invasive Estimation of Left Ventricular Filling Pressures using the E/Em index2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Aims: Tissue Doppler (TD) in spectral mode (spectral TD) and color TD are the two modalities available today in tissue velocity echocardiography (TVE). Measurements of left ventricular (LV) myocardial velocities and displacement may yield different results depending on the employed sonographic modality and the subjective adjustments during data analysis. The ratio of transmitral early diastolic velocity (E) to early diastolic myocardial velocity (Em) has been suggested as a non-invasive estimate of LV filling pressures. The present studies aimed to evaluate the compatibility between the two TD modalities and the effect of temporal filtering and offline gain on velocity and displacement measurements obtained using these two methods. The validity of E/Em in identifying elevated LV filling pressures after acute reductions in hemodynamic LV loading was assessed.

    Methods and Results: In 57 patients, longitudinal myocardial velocity profiles were acquired from the basal LV segments, using spectral and color TD. Peak systolic (Sm) and early diastolic (Em) myocardial velocities and the myocardial displacement during the ejection phase were measured offline. Spectral TD measurements were performed using three different gain settings (0%-, 50%- 100% offline gain). Color TD analysis were performed before and after the application of temporal filtering at 30, 50 and 70 ms filter width. The E/Em ratio was calculated at the different settings. The correlation between spectral- and color TD measurements was good. Changes in offline gain and filter width resulted in significant alterations on spectral and color TD derived measurements, respectively. Sm and Em were significantly higher (p < 0.001) whereas the E/Em was significantly lower (p < 0.001) for measurements performed with spectral TD compared to color TD and the discrepancy among the measurements increased at increasing filter width and gain level. In Study II the results of spectral- and color TD derived displacement were compared to anatomic M-mode. Spectral TD at different gain settings significantly overestimated M-mode derived displacement measurements, whereas the concordance between color TD and M-mode was considerably better.

    In Study III, LV longitudinal systolic myocardial velocities and displacement during ejection period were quantified at the basal septal and lateral wall in 24 healthy individuals using spectral TD, color TD and M-mode. Mean spectral TD systolic velocity and displacement values were obtained from the outer and inner borders of the spectral velocity signal. The estimated mean spectral TD systolic myocardial velocities were highly concordant with corresponding color TD measurements (mean difference 0.1 ± 0.6 cm/s, septal wall; 0.1 ± 1.0 cm/s, lateral wall). Similarly, myocardial displacement obtained by integration over time of mean spectral TD velocities was in good agreement with color TD (mean difference 0.2 ± 0.7 mm, septal wall; 0.02 ± 0.86 mm, lateral wall) as well as with the corresponding M-mode measurements.

    In Study IV, simultaneous LV catheterization and echocardiographic examination was performed in 68 consecutive patients referred for coronary angiography. Doppler signals of the transmitral flow and spectral TD signals at the level of mitral annulus were obtained and the E/Em was then calculated. All examinations were repeated after nitroglycerin (NTG) infusion. At baseline, the predictive ability of E/Em in identifying elevated LVDP was modest at best (area under curve [AUC] ± SE = 0.71 ± 0.08, p < 0.01). The index was more strongly associated with LVDP in patients with reduced ejection fraction (EF) < 55% (r = 0.68; p < 0.01) compared to patients with EF ≥ 55%(r = 0.4; p < 0.05). Following NTG administration, the diagnostic ability of E/Em in detecting elevated LVDP was significantly reduced (area under curve [AUC] ± SE =0.6 ± 0.08, p > 0.05). Changes in LVDP were not reliably tracked using E/Em (p > 0.05).

    Conclusions: Spectral TD yields significantly higher myocardial velocity and displacement values and lower E/Em compared to color TD modality. Increasing gain and temporal smoothing significantly alters the obtained velocity and displacement information and yield greater disparity between measurements derived using the two TD methods. Spectral TD significantly overestimates myocardial displacement obtained using M-mode. On the other hand, the agreement between color TD and anatomic M-mode is considerably better. Measurements based on mean spectral TD velocities were highly concordant with those provided by color TD and M-mode. However, unfavorable limits of agreement discourage the interchangeable use of these modalities. The diagnostic ability of E/Em was poor and declined significantly following acute reduction in LV hemodynamic loading. Changes in LVDP were not predicted by alterations in E/Em. Our findings imply that E/Em might not be sufficiently robust to be employed as a single non-invasive estimate for tailoring medical therapy in patients with elevated LVDP.

  • 47.
    Manouras, Aristomenis
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Nyktari, Evangelia
    Sahlén, Anders
    Winter, Reidar
    Vardas, Panagiotis
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    The value of E/Em ratio in the estimation of left ventricular filling pressures: impact of acute hemodynamic load reductionManuscript (preprint) (Other academic)
  • 48.
    Martufi, Giampaolo
    et al.
    KTH, School of Technology and Health (STH). Univ Calgary, Dept Civil Engn, Calgary, AB, Canada.
    Forneris, Arianna
    Univ Calgary, Biomed Engn Grad Program, Calgary, AB, Canada..
    Nobakht, Samaneh
    Univ Calgary, Biomed Engn Grad Program, Calgary, AB, Canada..
    Rinker, Kristina D.
    Univ Calgary, Dept Chem & Petr Engn, Calgary, AB, Canada.;Univ Calgary, Ctr Bioengn Res & Educ, Calgary, AB, Canada.;Univ Calgary, Libin Cardiovasc Inst Alberta, Calgary, AB, Canada..
    Moore, Randy D.
    Univ Calgary, Dept Surg, Calgary, AB, Canada..
    Di Martino, Elena S.
    Univ Calgary, Dept Civil Engn, Calgary, AB, Canada.;Univ Calgary, Ctr Bioengn Res & Educ, Calgary, AB, Canada.;Univ Calgary, Libin Cardiovasc Inst Alberta, Calgary, AB, Canada..
    Case Study: Intra-Patient Heterogeneity of Aneurysmal Tissue Properties2018In: Frontiers in Cardiovascular Medicine, ISSN 2297-055X, Vol. 5, article id 82Article in journal (Refereed)
    Abstract [en]

    Introduction: Current recommendations for surgical treatment of abdominal aortic aneurysms (AAAs) rely on the assessment of aortic diameter as a marker for risk of rupture. The use of aortic size alone may overlook the role that vessel heterogeneity plays in aneurysmal progression and rupture risk. The aim of the current study was to investigate intra-patient heterogeneity of mechanical and fluid mechanical stresses on the aortic wall and wall tissue histopathology from tissue collected at the time of surgical repair. Methods: Finite element analysis (FEA) and computational fluid dynamics (CFD) simulations were used to predict the mechanical wall stress and the wall shear stress fields for a non-ruptured aneurysm 2 weeks prior to scheduled surgery. During open repair surgery one specimen partitioned into different regions was collected from the patient's diseased aorta according to a pre-operative map. Histological analysis and mechanical testing were performed on the aortic samples and the results were compared with the predicted stresses. Results: The preoperative simulations highlighted the presence of altered local hemodynamics particularly at the proximal segment of the left anterior area of the aneurysm. Results from the post-operative assessment on the surgical samples revealed a considerable heterogeneity throughout the aortic wall. There was a positive correlation between elastin fragmentation and collagen content in the media. The tensile tests demonstrated a good prediction of the locally varying constitutive model properties predicted using geometrical variables, i.e., wall thickness and thrombus thickness. Conclusions: The observed large regional differences highlight the local response of the tissue to both mechanical and biological factors. Aortic size alone appears to be insufficient to characterize the large degree of heterogeneity in the aneurysmal wall. Local assessment of wall vulnerability may provide better risk of rupture predictions.

  • 49. Mattsson, C. M.
    et al.
    Lind, Britta
    KTH, School of Technology and Health (STH), Medical Engineering.
    Enqvist, J. K.
    Mårtensson, Mattias
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Ekblom, B.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    No evidence of cardiac fatigue in tissue velocity curves at rest after 6 days of ultra-endurance exercise2010In: European Heart Journal, ISSN 0195-668X, E-ISSN 1522-9645, Vol. 31, p. 304-305Article in journal (Refereed)
  • 50. Medrano-Gracia, Pau
    et al.
    Ormiston, John
    Webster, Mark
    Beier, Susann
    Young, Alistair
    Ellis, Chris
    Wang, Chunliang
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Smedby, Örjan
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Cowan, Brett
    A computational atlas of normal coronary artery anatomy2016In: EuroIntervention, ISSN 1774-024X, E-ISSN 1969-6213, Vol. 12, no 7, p. 845-854Article in journal (Refereed)
    Abstract [en]

    Aims: The aim of this study was to define the shape variations, including diameters and angles, of the major coronary artery bifurcations. Methods and results: Computed tomographic angiograms from 300 adults with a zero calcium score and no stenoses were segmented for centreline and luminal models. A computational atlas was constructed enabling automatic quantification of 3D angles, diameters and lengths of the coronary tree. The diameter (mean +/- SD) of the left main coronary was 3.5 +/- 0.8 mm and the length 10.5 +/- 5.3 mm. The left main bifurcation angle (distal angle or angle B) was 89 +/- 21 degrees for cases with, and 75 +/- 23 degrees for those without an intermediate artery (p<0.001). Analogous measurements of diameter and angle were tabulated for the other major bifurcations (left anterior descending/diagonal, circumflex/obtuse marginal and right coronary crux). Novel 3D angle definitions are proposed and analysed. Conclusions: A computational atlas of normal coronary artery anatomy provides distributions of diameter, lengths and bifurcation angles as well as more complex shape analysis. These data define normal anatomical variation, facilitating stent design, selection and optimal treatment strategy. These population models are necessary for accurate computational flow dynamics, can be 3D printed for bench testing bifurcation stents and deployment strategies, and can aid in the discussion of different approaches to the treatment of coronary bifurcations.

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