Non-invasive determination of left ventricular workload in patients with aortic stenosis using magnetic resonance imaging and Doppler echocardiographye

Early detection and accurate estimation of aortic stenosis (AS) severity are the most important predictors of successful longterm outcomes in patients. Current clinical parameters used for evaluation of the AS severity have several limitations including flow dependency. Estimation of AS severity is specifically challenging in patients with low-flow and low transvalvular pressure gradient conditions. A proper diagnosis in these patients needs a comprehensive evaluation of the left ventricle (LV) hemodynamic loads. This study has two objectives: (1) developing a lumped-parameter model to describe the ventricular-valvular-arterial interaction and to estimate the LV stroke work (SW); (2) introducing and validating a new index, the normalized stroke work (N-SW), to assess the global hemodynamic load imposed on the LV. N-SW represents the global hemodynamic load that the LV faces for each unit volume of blood ejected. The model uses a limited number of parameters which all can be measured non-invasively using current clinical imaging modalities. The model was first validated by comparing its calculated flow waveforms with the ones measured using Cardiovascular Magnetic Resonance (CMR) in 49 patients and 8 controls. A very good correlation and concordance were found throughout the cycle (median root mean square: 12.21 mL/s) and between the peak values (r = 0.98; SEE = 0.001, p,0.001). The model was then used to determine SW using the parameters measured with transthoracic Doppler-echocardiography (TTE) and CMR. N-SW showed very good correlations with a previously-validated index of global hemodynamic load, the valvular arterial impedance (ZVA), using data from both imaging modalities (TTE: r = 0.82, SEE = 0.01, p,0.001; CMR: r = 0.74, SEE = 0.01, p,0.001). Furthermore, unlike , N-SW was almost independent from variations in the flow rate. This study suggests that considering N-SW may provide incremental diagnostic and prognostic information, beyond what standard indices of stenosis severity and provide, particularly in patients with low LV outflow

Impact of classic and paradoxical low flow on survival after aortic valve replacement for severe aortic stenosis

BackgroundLow flow (LF) can occur with reduced (classic) or preserved (paradoxical) left ventricular ejection fraction (LVEF). ObjectivesThe objective of this study was to compare outcomes of patients with low ejection fraction (LEF), paradoxical low flow (PLF), and normal flow (NF) after aortic valve replacement (AVR). MethodsWe examined 1,154 patients with severe aortic stenosis (AS) who underwent AVR with or without coronary artery bypass grafting. ResultsAmong these patients, 206 (18%) had LEF as defined by LVEF of 35 ml · m2. Aortic valve area was lower in low flow/LVEF groups (LEF: 0.71 ± 0.20 cm2 and PLF: 0.65 ± 0.23 cm2 vs. NF: 0.77 ± 0.18 cm2; p < 0.001). The 30-day mortality was higher (p < 0.001) in LEF and PLF groups than in the NF group (6.3% and 6.3% vs. 1.8%, respectively). SVi and PLF group were independent predictors of operative mortality (odds ratio [OR]: 1.18, p < 0.05; and OR: 2.97, p = 0.004; respectively). At 5 years after AVR, overall survival was 72 ± 4% in LEF group, 81 ± 2% in PLF group, and 85 ± 2% in NF group (p < 0.0001). ConclusionsPatients with LEF or PLF AS have a higher operative risk, but pre-operative risk score accounted only for LEF and lower LVEF. Patients with LEF had the worst survival outcome, whereas patients with PLF and normal flow had similar survival rates after AVR. As a major predictor of perioperative mortality, SVi should be integrated in AS patients’ pre-operative evaluation

Effect of regional upper septal hypertrophy on echocardiographic assessment of left ventricular mass and remodeling in aortic stenosis

Transthoracic echocardiography (TTE) is the reference method for evaluation of aortic stenosis (AS), and it is extensively used to quantitate left ventricular (LV) mass and volumes. Regional upper septal hypertrophy (USH) or septal bulge is a frequent finding in patients with AS and may lead to overestimation of LV mass when using linear measurements. The objective of this study was to compare estimates of LV mass obtained by two-dimensional transthoracic echocardiographic LV dimensions measured at different levels of the LV cavity with those obtained by cardiovascular magnetic resonance (CMR). Methods: One hundred six patients (mean age, 63 6 15 years; 68% men) with AS were included in this subanalysis of the PROGRESSA study. Two-dimensional transthoracic echocardiographic measurements of LV dimensions were obtained at the basal level (BL; as recommended in guidelines), immediately below the septal bulge (BSB), and at a midventricular level (ML). Regional USH was defined as a basal interventricular septal thickness $ 13 mm and >1.3 times the thickness of the septal wall at the ML. Agreement between transthoracic echocardiographic and CMR measures was evaluated using Bland-Altman analysis. Results: The distribution of AS severity was mild in 23%, moderate in 57%, and severe in 20% of patients. Regional USH was present in 28 patients (26%). In the whole cohort, two-dimensional TTE overestimated LV mass (bias: BL, +60 6 31 g; BSB, +59 6 32 g; ML, +54 6 32 g; P = .02). The biplane Simpson method slightly but significantly underestimated LV end-diastolic volume (bias 10 6 20 mL, P < .001) compared with CMR. Overestimation of LV mass was more marked in patients with USH when measuring at the BL and was significantly lower when measuring LV dimensions at the ML (P < .025 vs BL and BSB). Conclusions: Two-dimensional TTE systematically overestimated LV mass and underestimated LV volumes compared with CMR. However, the bias between TTE and CMR was less important when measuring at the ML. Measurements at the BL as suggested in guidelines should be avoided, and measurements at the ML should be preferred in patients with AS, especially in those with USH

Visceral adiposity and left ventricular mass and function in patients with aortic stenosis : the PROGRESSA study

Background : Recent studies have reported that obesity, metabolic syndrome, and diabetes are associated with left ventricular (LV) hypertrophy (LVH) and dysfunction in patients with aortic stenosis (AS). The purpose of this study was to examine the association between amount and distribution of body fat and LVH and systolic dysfunction in AS patients. Methods : One hundred twenty-four patients with AS were prospectively recruited in the PROGRESSA (Metabolic Determinants of the Progression of Aortic Stenosis) study and underwent Doppler echocardiography and computed tomography scan. Presence and severity of LVH was assessed according to LV mass indexed for height2.7 and LV dysfunction according to global longitudinal strain (GLS). Computed tomography was used to quantify abdominal visceral (VAT) and subcutaneous (SAT) adipose tissue, and total adipose tissue (TAT). Results : Body mass index (BMI) correlated strongly with TAT (r = 0.85), moderately with VAT (r = 0.70), and SAT (r = 0.69), and weakly with the proportion of VAT (VAT/TAT ratio: r = 0.19). In univariate analysis, greater BMI, TAT, VAT, SAT, and VAT/TAT were associated with increased LV mass index and greater VAT and VAT/TAT ratio were associated with reduced GLS. Multivariate analysis revealed that larger BMI (P < 0.0001) and greater VAT/TAT ratio (P = 0.01) were independently associated with higher prevalence of LVH, and only the VAT/TAT ratio (P = 0.03) was independently associated with reduced GLS. Conclusions : The results of this study suggest that total and visceral adiposity are independently associated with LVH in patients with AS. Furthermore, impairment of LV systolic function does not appear to be influenced by total obesity but is rather related to excess visceral adiposity. These findings provide impetus for elaboration of interventional studies aiming at visceral adiposity in the AS population.De récentes études ont rapporté que l’obésité, le syndrome métabolique et le diabète étaient associés à l’hypertrophie (HVG) et à la dysfonction ventriculaire gauche des patients souffrant d’une sténose aortique (SA). Le but de cette étude était d’examiner le lien entre la quantité et la répartition de la graisse corporelle, l’HVG et la dysfonction systolique chez les patients souffrant d’une SA. Méthodes : Cent vingt-quatre patients souffrant d’une SA ont été recrutés de manière prospective dans l’étude PROGRESSA (Metabolic Determinants of the Progression of Aortic Stenosis), et ont subi une échocardiographie Doppler et une tomodensitométrie. La présence et la sévérité de l’HVG ont été évaluées au moyen de la masse VG indexée par la taille2.7 et la dysfonction systolique du VG par la déformation longitudinale globale du VG (DLG). La tomodensitométrie a été utilisée pour quantifier le tissu adipeux abdominal viscéral (TAV) et sous-cutané (TAS), et le tissu adipeux total (TAT). Résultats : L’indice de masse corporelle (IMC) corrélait fortement avec le TAT (r = 0,85), modérément avec le TAV (r = 0,70) et le TAS (r = 0,69), et faiblement avec la proportion de TAV (rapport TAV/TAT : r = 0,19). En analyse multivariée, des IMC, TAT, TAV, TAS et VAT/TAT plus élevés étaient associés à une augmentation de la masse VG indexée et un TAV et un rapport TAV/TAT plus élevés étaient associés à la réduction de la DLG. L’analyse multivariée a révélé qu’un IMC plus élevé (P < 0,0001) et un rapport TAV/TAT plus élevé (P = 0,01) étaient indépendamment associés à une HVG plus importante, et seul un rapport TAV/TAT était indépendamment associé à une réduction de la DLG. Conclusions : Les résultats de cette étude montrent que l’adiposité totale et l'adiposité viscérale sont indépendamment associées à une HVG chez les patients souffrant d’une SA. De plus, la détérioration de la fonction systolique VG ne semble pas être influencée par l’obésité totale, mais est plutôt liée à une adiposité viscérale excessive. Ces résultats incitent à l’élaboration d’études interventionnelles visant l’adiposité viscérale dans la population souffrant de SA

Impact of Low Flow on the Outcome of High-Risk Patients Undergoing Transcatheter Aortic Valve Replacement

ObjectivesThis study sought to assess the impact of baseline left ventricular (LV) outflow, LV ejection fraction (LVEF), and transvalvular gradient on outcomes following transcatheter aortic valve replacement (TAVR) in patients with severe aortic stenosis (AS).BackgroundLow flow (i.e., reduced stroke volume index [SVi]) can occur with both reduced and preserved LVEF. Low flow is often associated with low gradient despite severe stenosis and with worse outcomes following surgical aortic valve replacement. However, there are few data about the impact of low flow on outcomes following TAVR.MethodsWe retrospectively analyzed the clinical, Doppler-echocardiographic, and outcome data prospectively collected in 639 patients who underwent TAVR for symptomatic severe AS in 2 Canadian centers.ResultsIn this cohort, 334 (52.3%) patients had a low flow (SVi <35 ml/m2) and these patients had increased 30-day mortality (11.4 vs. 5.9%, p = 0.01), 2-year all-cause mortality (35.3 vs. 30.9%, p = 0.005), and 2-year cardiovascular mortality (25.7 vs. 16.8%, p = 0.01) compared with patients with normal flow. Reduced flow was an independent predictor of 30-day mortality (odds ratio: 1.94, p = 0.026), cumulative all-cause mortality (hazard ratio: 1.27 per 10 ml/m² SVi decrease, p = 0.016), and cumulative cardiovascular mortality (hazard ratio: 1.29 per 10 ml/m² decrease, p = 0.04). Despite significant association in univariable analyses, low LVEF and low mean gradient were not found to be independent predictors of outcomes in multivariable analyses.ConclusionsLow flow but not low LVEF or low gradient is an independent predictor of early and late mortality following TAVR in high-risk patients with severe AS. SVi should be integrated in the risk stratification process of these patients

Myocardial injury following transcatheter aortic valve implantation : insights from delayed-enhancement cardiovascular magnetic resonance

Aims: The aim of this study was to evaluate the presence, localisation and extent of myocardial injury as determined by late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) imaging in patients undergoing transcatheter aortic valve implantation (TAVI). Methods and results: A total of 37 patients, who underwent successful TAVI with a balloon-expandable valve (transapical [TA], n=11; non-TA, n=26), were included. Cardiac biomarker (CK-MB and cTnT) lev- els were determined at baseline and following TAVI. CMR was performed within a week before and within 30 days following TAVI. Some increase in cardiac biomarkers was detected in 97% of the patients as deter- mined by a rise in cTnT, and in 49% of the patients as determined by a rise in CK-MB. Following TAVI, no new myocardial necrosis defects were observed with the non-TA approach. Nonetheless, all patients who underwent TAVI through the TA approach had new focal myocardial necrosis in the apex, with a median myo-cardial extent and necrotic mass of 5% [2.0-7.0] and 3.5 g [2.3-4.5], respectively. Conclusions: Although some increase in cardiac biomarkers of myocardial injury was systematically detected following TAVI, new myocardial necrosis as evaluated by CMR was observed only in patients undergoing the procedure through the TA approach, involving ~5% of the myocardium in the apex

Prognostic impact of cardiac output in aortic valve stenosis

La sténose aortique (SA) est la maladie valvulaire cardiaque ayant la plus forte prévalence dans les pays occidentaux. On s’aperçoit que, malgré le respect des recommandations pour les indications opératoires, les patients présentent des évolutions très variables après chirurgie : certains patients restent symptomatiques, décèdent précocement, ou présentent une dysfonction ventriculaire gauche persistante. Il a été montré que les patients présentant à la fois une SA en bas débit (c’est-à-dire un volume d’éjection bas), une fraction d’éjection ventriculaire gauche (FEVG) altérée et un gradient de pression entre le ventricule et l’aorte abaissé avaient un pronostic péjoratif, avec un risque opératoire majoré lorsqu’ils subissaient un remplacement valvulaire chirurgical. Il a aussi été récemment démontré que, dans le contexte de la SA, un bas débit peut survenir alors que la FEVG est normale. Les objectifs généraux de ce doctorat sont d’étudier l’impact du débit (plus précisément le volume d’éjection ventriculaire gauche) sur le pronostic des patients atteints de SA, ainsi que l’évolution du débit après intervention et les déterminants de son évolution. Les résultats indiquent que le volume d’éjection ventriculaire gauche, que ce soit avant intervention, ou son évolution après TAVI (Transcatheter Aortic Valve Implantation), sont des prédicteurs indépendants puissants de mortalité chez ces patients.Aortic stenosis (AS) is the most common valvular heart disease in occidental countries. Despite proper use of the guidelines, some patients can present adverse outcomes after surgery: some of them remain symptomatic, some die prematurely, or suffer from a persistant left ventricular dysfunction. It has been demonstrated that patients presenting an AS with low flow (i.e. low stroke volume), impaired left ventricular ejection fraction (LVEF), and a low transvalvular mean gradient, have poor prognosis, with increased risk during aortic valve replacement surgery. It has also been demonstrated that, in AS, a low flow can occur despite a preserved LVEF. The main goals of this PhD were to evaluate the impact of flow (more precisely left ventricular stroke volume) on the prognosis of patients with AS, the evolution of flow after intervention, and the factors that influence it. The results show that left ventricular stroke volume, before or after intervention, or its evolution after TAVI (Transcatheter Aortic Valve Implantation), are powerful independant predictors of mortality

Impact pronostique du débit cardiaque dans la sténose valvulaire aortique

Aortic stenosis (AS) is the most common valvular heart disease in occidental countries. Despite proper use of the guidelines, some patients can present adverse outcomes after surgery: some of them remain symptomatic, some die prematurely, or suffer from a persistant left ventricular dysfunction. It has been demonstrated that patients presenting an AS with low flow (i.e. low stroke volume), impaired left ventricular ejection fraction (LVEF), and a low transvalvular mean gradient, have poor prognosis, with increased risk during aortic valve replacement surgery. It has also been demonstrated that, in AS, a low flow can occur despite a preserved LVEF. The main goals of this PhD were to evaluate the impact of flow (more precisely left ventricular stroke volume) on the prognosis of patients with AS, the evolution of flow after intervention, and the factors that influence it. The results show that left ventricular stroke volume, before or after intervention, or its evolution after TAVI (Transcatheter Aortic Valve Implantation), are powerful independant predictors of mortality.La sténose aortique (SA) est la maladie valvulaire cardiaque ayant la plus forte prévalence dans les pays occidentaux. On s’aperçoit que, malgré le respect des recommandations pour les indications opératoires, les patients présentent des évolutions très variables après chirurgie : certains patients restent symptomatiques, décèdent précocement, ou présentent une dysfonction ventriculaire gauche persistante. Il a été montré que les patients présentant à la fois une SA en bas débit (c’est-à-dire un volume d’éjection bas), une fraction d’éjection ventriculaire gauche (FEVG) altérée et un gradient de pression entre le ventricule et l’aorte abaissé avaient un pronostic péjoratif, avec un risque opératoire majoré lorsqu’ils subissaient un remplacement valvulaire chirurgical. Il a aussi été récemment démontré que, dans le contexte de la SA, un bas débit peut survenir alors que la FEVG est normale. Les objectifs généraux de ce doctorat sont d’étudier l’impact du débit (plus précisément le volume d’éjection ventriculaire gauche) sur le pronostic des patients atteints de SA, ainsi que l’évolution du débit après intervention et les déterminants de son évolution. Les résultats indiquent que le volume d’éjection ventriculaire gauche, que ce soit avant intervention, ou son évolution après TAVI (Transcatheter Aortic Valve Implantation), sont des prédicteurs indépendants puissants de mortalité chez ces patients

Influence du site de stimulation ventriculaire droite sur la mortalité, la survenue d'insuffisance cardiaque et d'arythmies auriculaires à long terme

Classiquement, la stimulation ventriculaire droite s'effectue par implantation d'une sonde ventriculaire par voie veineuse sous-clavière ou céphalique à l'apex du ventricule droit. Les conséquences possibles de ce type de stimulation ventriculaire à long terme sont un remodelage ventriculaire, un trouble de la perfusion et de la cinétique segmentaire, une dysfonction ventriculaire systolique et/ou diastolique, une insuffisance mitrale fonctionnelle, une dilatation de l'oreillette gauche, des arythmies auriculaires et ventriculaires et l'activation du syste me nerveux sympathique. Notre étude évalue de manière rétrospective l'évolution de 150 patients stimulés dans le ventricule droit de façon permanente, implantés au CHU de Brest, afin de comparer différents sites de stimulation ventriculaire (108 à l'apex, 28 au septum inter-ventriculaire haut/infundibulum pulmonaire et 16 au septum inter-ventriculaire bas). Nos résultats montrent que chez les patients stimulés en permanence dans le ventricule droit, la localisation de la sonde ventriculaire ne semble pas avoir d'impact à long terme sur le pronostic en terme de mortalité ou de survenue d'insuffisance cardiaque. La localisation septale haute ou infundibulaire semble être associée à une incidence plus élevée de fibrillation atriale au long cours. Ce résultat sera à valider par des études prospectives randomisées multicentriques.BREST-BU Médecine-Odontologie (290192102) / SudocSudocFranceF

[Epidemiology and risk factors of venous thromboembolism].

International audienceINTRODUCTION: Venous thromboembolism (VTE) is a common disease. The incidence rises markedly with increasing age; over the age of 75, the annual incidence reaches 1 per 100. BACKGROUND: Besides major risk factors (surgery, trauma and acute medical illness), four risk factors have to be taken into account in the management of VTE: increasing age, cancer, previous history of VTE and pregnancy. To date, with the exception of the antiphospholipid syndrome and antithrombin deficiency, "thrombophilias" do not appear to change the management of VTE. VIEWPOINTS: "Thrombophilias" are useful tools for understanding the pathophysiology of VTE. Therefore, further studies are needed to identify new biological anomalies and their impact on the risk of VTE. Recently, links between VTE and atherosclerosis have been demonstrated, leading to new concept of pan-vascular disease and prevention. CONCLUSIONS: VTE is a major public health problem. The knowledge of VTE risk factors is of major importance in identifying high-risk patients and in reducing the incidence and mortality of VTE