From pressure overload to volume overload: aortic regurgitation after transcatheter aortic valve implantation

A novel balloon-expandable transcatheter aortic valve bioprosthesis: Myval and Myval Octacor

INTRODUCTION

Over the past two decades, transcatheter aortic valve replacement (TAVR) has expanded its application across all surgical risk levels, including low-risk patients, where, due to longer life expectancy, reducing common pitfalls of TAVR is essential. To address these needs, many technological advancements have been developed. Myval and the new generation Myval Octacor (Meril Life Sciences Pvt. Ltd) are novel balloon-expandable (BE) transcatheter heart valve (THV) systems designed for the treatment of severe aortic stenosis.

AREAS COVERED

This review aims to illustrate the design features of these novel THVs and the main evidence from available studies. Furthermore, we provide evidence of these THVs' performance in challenging scenarios such as extra-large aortic annuli, bicuspid aortic valves, and valve-in-valve/valve-in-ring procedures.

EXPERT OPINION

Myval and Myval Octacor have demonstrated comparable early safety and clinical efficacy to the leading contemporary THVs, exhibiting remarkably low rates of moderate to severe paravalvular leak (PVL) and permanent pacemaker implantation (PPI). The wide range of sizes offered by the Myval family may minimize the risk of under-/oversizing, potentially explaining the lower rates of the aforementioned phenomena. Moreover, the presence of both internal skirt and external reinforced cuff may also explain the low rate of moderate to severe PVL.

Paravalvular regurgitation after transcatheter aortic valve replacement: incidence, quantification, and prognostic impact

Transcatheter aortic valve replacement (TAVR) is the standard of care in aortic stenosis with results comparable to surgical aortic valve replacement. However, paravalvular regurgitation (PVR) is more common after TAVR. With the alteration of devices and implantation techniques, the incidence of moderate or more PVR has declined. Mild PVR is still common in around 30% of TAVR patients in low-risk trials. Progression of AS causes myocardial hypertrophy and varying degrees of diastolic dysfunction which may cause heart failure even in combination with small volumes of PVR. Any degree of PVR is associated with an increased risk of overall and cardiovascular mortality. Predictors of PVR are annular eccentricity, severe calcification of the aortic valve, bicuspid aortic valves, and type of prosthesis where balloon-expandable devices are associated with less PVR. PVR is diagnosed using echocardiography, aortic angiogram with or without videodensitometry, haemodynamic parameters, or cardiac magnetic resonance. PVR can be treated using post-dilation, interventional treatment using a vascular plug, or implantation of a second device. Successful post-dilation depends on balloon size which should at least be equal to or >95% of the mean annulus diameter. Implantation of a second device to reduce PVR is successful in ∼90% of cases, either through lengthening of the sealing skirt in case of inadequate position or through further expansion of the index device. Implantation of a vascular plug can successfully reduce PVR and reduce mortality.

Strain Assessment in Aortic Stenosis: Pathophysiology and Clinical Utility

Contemporary echocardiographic criteria for grading aortic stenosis severity have remained relatively unchanged, despite significant advances in noninvasive imaging techniques over the last 2 decades. More recently, attention has shifted to the ventricular response to aortic stenosis and how this might be quantified. Global longitudinal strain, semiautomatically calculated from standard two-dimensional echocardiographic images, has been the focus of extensive research. Global longitudinal strain is a sensitive marker of subtle hypertrophy-related impairment in left ventricular function and has shown promise as a relatively robust prognostic marker, both independently and when added to severity classification systems. Herein we review the pathophysiological basis underpinning the potential utility of global longitudinal strain in the assessment of aortic stenosis, as well as its potential role in quantifying myocardial recovery and prognostic discrimination following aortic valve replacement.

Mild aortic insufficiency following transcatheter aortic valve replacement: A systematic review and meta-analysis

BACKGROUND

Post-procedural aortic insufficiency (AI) continues to be prevalent following transcatheter aortic valve replacement (TAVR). While several studies have assessed the outcomes of moderate-severe AI following TAVR, the incidence, predictors, and outcomes of mild AI remain unclear.

METHODS

A systematic literature review was performed to identify studies reporting on mild AI following TAVR. The primary outcome was pooled incidence of post-TAVR mild AI. Secondary outcomes included pooled incidence of mild AI at 30 days and long term. The pooled incidence of midterm mortality in patients with post-TAVR mild AI was also evaluated. The random effect generalized linear mixed-effects model with logit-transformed proportions and Hartung-Knapp adjustment was used to calculate pooled incidence rates. Meta-regression was performed to identify predictors of mild AI.

RESULTS

The pooled analysis included 19,241 patients undergoing TAVR across 50 studies. The mean age of patients ranged from 73 to 85 years, and female patients ranged from 20.0% to 83.3%. The overall pooled incidence of post-TAVR mild AI was 56.1% (95% confidence interval [CI] 0.31-0.64). The pooled incidence of mild AI at 30 days was 33.7% (95% CI 0.12-0.37). At mean follow-up of 1.15 years, the pooled incidence of mild AI was 37.0% (95% CI 0.16-0.45). The overall pooled incidence of Midterm mortality (mean follow-up 1.22 years) in patients with mild AI was 14.8% (95% CI 0.10-0.25). At meta-regression, none of the explored variables correlated with a difference in mild AI incidence.

CONCLUSIONS

In published studies to date, 50% of patients undergoing TAVR develop mild AI postoperatively. In 37% of patients, this persists in long term. Though the incidence of AI is likely improving with newer generation TAVR valves, the prevalence and outcomes of mild AI should be closely monitored as TAVR volume and indications expand to younger patients with long life expectancy. The long-term outcomes of mild AI remain unclear. Further dedicated studies on post-TAVR mild AI are needed.

Redo aortic valve replacement versus valve-in-valve trans-catheter aortic valve implantation: a UK propensity-matched analysis

This study sought to compare the morbidity and mortality of redo aortic valve replacement (redo-AVR) versus valve-in-valve trans-catheter aortic valve implantation (valve-in-valve TAVI) for patients with a failing bioprosthetic valve. A multicenter UK retrospective study of redo-AVR or valve-in-valve TAVI for patients referred for redo aortic valve intervention due to a degenerated aortic bioprosthesis. Propensity score matching was performed for confounding factors. From July 2005 to April 2021, 911 patients underwent redo-AVR and 411 patients underwent valve-in-valve TAVI. There were 125 pairs for analysis after propensity score matching. The mean age was 75.2±8.5 years. In-hospital mortality was 7.2% (n=9) for redo-AVR versus 0 for valve-in-valve TAVI, p=0.002. Surgical patients suffered more post-operative complications, including intra-aortic balloon pump support (p=0.02), early re-operation (p<0.001), arrhythmias (p<0.001), respiratory and neurological complications (p=0.02 and p=0.03) and multi-organ failure (p=0.01). The valve-in-valve TAVI group had a shorter intensive care unit and hospital stay (p<0.001 for both). However, moderate aortic regurgitation at discharge and higher post-procedural gradients were more common after valve-in-valve TAVI (p<0.001 for both). Survival probabilities in patients who were successfully discharged from the hospital were similar after valve-in-valve TAVI and redo-AVR over the 6-year follow-up (log-rank p=0.26). In elderly patients with a degenerated aortic bioprosthesis, valve-in-valve TAVI provides better early outcomes as opposed to redo-AVR, although there was no difference in mid-term survival in patients successfully discharged from the hospital.

A rare delayed complication after TAVR: Acute severe aortic insufficiency

Transcatheter aortic valve replacement (TAVR) has become the standard of care for managing severe aortic stenosis (AS) in high surgical risk patients. Despite favorable outcomes, TAVR has been associated with complications, such as aortic regurgitation (AR). Post-TAVR aortic insufficiency, which can present at any time after the procedure, manifests as paravalvular leak, central leak, or a combination of the two. Herein, we describe a unique and atypical case of a patient who presented with heart failure and was found to have severe AR in the context of having had TAVR 5 years prior using an Evolut R prosthetic valve.

The effect of the learning curve on paravalvular aortic regurgitation and mid-term mortality in transfemoral transcatheter aortic valve implantation

OBJECTIVE

Paravalvular aortic regurgitation is an important independent mortality predictor in transcatheter aortic valve implantation (TAVI). Our study evaluated the association between paravalvular aortic regurgitation and mid-term mortality in relation with the learning curve, in patients with severe aortic stenosis who underwent transfemoral TAVI in the first 3 years since the establishment of the program.

METHODS

Patients with severe aortic stenosis who underwent transfemoral TAVI between 2017 and 2020 were included in the analysis. Paravalvular aortic regurgitation was assessed by transthoracic echocardiography at 48 hours after the procedure. All-cause mortality was evaluated after 30 days and at mid-term follow-up.

RESULTS

Paravalvular aortic regurgitation ≥grade II was associated with mid-term all-cause mortality (OR 4.4; 95%CI 1.82-11.55; p < 0.001), their prevalence declining after the first 60 cases. Baseline characteristics did not significantly differ in the first 60 patients from the rest of the cohort. Male sex (p = 0.006), advanced age (p = 0.04), coronary artery disease (p = 0.003), or elevated STS Score (p = 0.02) influenced mid-term survival. When adjusting for the presence of these factors, only age (OR 1.1; 95%CI 1.0-1.2), paravalvular aortic regurgitation ≥grade II (OR 3.9; 95%CI 1.3-12.9), and the number of days spent in the intensive care unit (OR 1.4; 95%CI 1.1-1.8) were independent predictors of mid-term all-cause mortality.

CONCLUSIONS

In a group of patients with severe aortic stenosis who underwent transfemoral TAVI in the first 3 years since the establishment of the program, paravalvular aortic regurgitation ≥grade II was associated with mid-term mortality, both declining after the first 60 cases.

Predictors and impact of low diastolic blood pressure and widened pulse pressure following transcatheter aortic valve replacement

BACKGROUND

The association between post-operative diastolic blood pressure (DBP) and pulse pressure (PP) with outcomes following transcatheter aortic valve replacement (TAVR) remains unclear. We sought to assess the prevalence, predictors, and impact of post-operative DBP and PP on presence of post-procedural aortic insufficiency (AI) and mortality in adults undergoing TAVR.

METHODS

The study population included 194 patients who underwent TAVR from 2016 to 2017 at an academic tertiary medical center, of which 176 had invasive arterial pressures available postoperatively. Low DBP and widened PP were defined as ≤40 mmHg and ≥80 mmHg respectively on invasive arterial line on post-operative day 1. Clinical outcomes of interest included post-procedural AI and 1-year all-cause mortality.

RESULTS

Post-operative low DBP and widened PP were noted in 32.4% and 58.5% of the study population. No significant association between post-operative AI and low DBP (p = 0.82) or widened PP (p = 0.32) was noted. There was a trend toward higher rates of mortality in patients with low DBP (19.3% vs 9.2%, p = 0.06) but no difference in mortality in patients with widened PP (10.7% vs 15.1%, p = 0.39) or those with ≥1+ post-procedural AI (16.7% vs 10.7%, p = 0.32). In multivariable analysis, low DBP was associated with a trend toward higher rates of 1-year mortality [odds ratio (OR) 2.43, 95% confidence interval (CI) 0.97-6.11, p = 0.06]. When excluding patients with a post-operative invasive systolic blood pressure < 80 mmHg, low DBP was associated with significantly higher risk-adjusted mortality at 1 year [OR 2.75, 95% CI (1.07-7.07), p = 0.04].

CONCLUSIONS

In this contemporary study of adults undergoing TAVR, low DBP and widened PP were widely prevalent post TAVR. Low DBP was associated with a trend toward higher rates of 1-year mortality but not with post-procedural AI.

Influence of Left Ventricular Function on the "Aortic Regurgitation Index" Proposed for the Hemodynamic Assessment of Postprocedural Aortic Regurgitation

The aortic regurgitation (AR) index, proposed as an objective indicator of postprocedural AR, decreases in proportion to AR severity, besides reportedly providing additional prognostic information. Meanwhile, left ventricular (LV) function has also been considered an essential prognostic factor. This study aimed to clarify whether LV function affected the AR index using cardiac catheterization data.A retrospective study was performed in patients whose LV function was evaluated using a micromanometer-tipped catheter. Patients with grade 2 or higher AR were excluded to explore non-AR factors affecting the AR index value. The AR index was calculated as a ratio of the gradient between the aortic diastolic blood pressure (DBP) and the LV end-diastolic pressure (EDP) to the aortic systolic blood pressure (SBP): AR Index = [ (DBP - LVEDP) / SBP] × 100.A total of 64 patients [age, 62 (interquartile range: 48-70) years; LV ejection fraction, 19% (16%-26%) ] were examined. AR index values ranged from 18.3 to 68.6. Despite having no AR, two patients displayed an AR index < 25, indicating significant AR. Multiple-regression analysis revealed that LV diastolic stiffness (β = -0.750, P < 0.001), LV max dP/dt (β = -0.296, P = 0.006), and heart rate (β = 0.284, P = 0.011) were independent determinants of the AR index value.Patients with impaired LV diastolic function and preserved systolic function had low AR index values. The additional prognostic information of the AR index may be related to LV diastolic function.

Prognostic impact of left ventricular mass regression after transcatheter aortic valve replacement in patients with left ventricular hypertrophy

BACKGROUND

Paravalvular regurgitation (PVR) has been known to be the primary determinant of poor left ventricular (LV) mass regression after transcatheter aortic valve replacement (TAVR). However, the incidence of significant PVR has been reduced considerably as TAVR technology evolved rapidly. This study aimed to investigate the time course and impact of LV mass index (LVMi) regression on long-term clinical outcomes in severe aortic stenosis (AS) patients without significant PVR after TAVR.

METHODS

Of 412 patients who underwent TAVR, 146 who had LV hypertrophy (LVMi ≥115 g/m² for men and ≥ 95 g/m² for women) at baseline and were alive at one year after TAVR were enrolled. The primary outcome was cardiovascular deaths and the impact of LVMi regression on clinical outcomes were examined. The patients with significant PVR were excluded.

RESULTS

During a median follow-up of 40 months (interquartile range, 26-58 months), 9 (6.2%) cardiovascular deaths, 21 (14.4%) all-cause deaths, and 9 (6.2%) hospitalizations occurred. In the multivariable analysis, the percentage change of LVMi was an independent predictor of cardiovascular deaths (adjusted hazard ratio [HR], 1.03; 95% confidential interval [CI], 1.01-1.05; P = 0.010), and composite outcome of cardiovascular deaths and rehospitalization for heart failure (adjusted HR, 1.02; 95% CI, 1.00-1.04; P = 0.022). Baseline LVMi, eccentric hypertrophy, and TAVR-induced left bundle branch block were independently associated with LVMi regression.

CONCLUSIONS

In patients with severe AS who received successful TAVR without significant PVR, the degree of LVMi regression is an independent predictor of postoperative outcomes after TAVR.

Impact of paravalvular leak on left ventricular remodeling and global longitudinal strain 1 year after transcatheter aortic valve replacement

Background: New mild or persistent moderate paravalvular leak (PVL) is a known predictor of poor outcomes after transcatheter aortic valve replacement (TAVR). Its impact on left ventricular (LV) remodeling and global longitudinal strain (GLS) has not been well studied. Materials & methods: We collected echocardiographic data in 99 TAVR patients. LV remodeling and GLS were compared between patients with and without PVL. Results: Patients without PVL (n = 84) had significant LV ejection fraction, wall thickness and LV mass improvement compared with patients with PVL (n = 15; p < 0.001 for all). Diastolic function worsened in patients with PVL. Baseline GLS improved significantly regardless of PVL (p = 0.016 and p = 0.01, respectively) and was not predictive of LV ejection fraction or LV mass improvement when analyzed in tertiles. Conclusion: PVL impedes reverse LV remodeling but not GLS improvement 1-year after TAVR. Baseline GLS was not a predictor of LV remodeling.

A thermodynamic transient cross-bridge model for prediction of contractility and remodelling of the ventricle

Cardiac hypertrophy is an adaption of the heart to a change in cardiovascular loading conditions. The current understanding is that progression may be stress or strain driven, but the multi-scale nature of the cellular remodelling processes have yet to be uncovered. In this study, we develop a model of the contractile left ventricle, with the active cell tension described by a thermodynamically motivated cross-bridge cycling model. Simulation of the transient recruitment of myosin results in correct patterns of ventricular pressure predicted over a cardiac cycle. We investigate how changes in tissue loading and associated deviations in transient force generation can drive restructuring of cellular myofibrils in the heart wall. Our thermodynamic framework predicts in-series sarcomere addition (eccentric remodelling) in response to volume overload, and sarcomere addition in parallel (concentric remodelling) in response to valve and signalling disfunction. This framework provides a significant advance in the current understanding of the fundamental sub-sarcomere level biomechanisms underlying cardiac remodelling. Simulations reveal that pathological tissue loading conditions can significantly alter actin-myosin cross-bridge cycling over the course of the cardiac cycle. The resultant variation in sarcomere stress pushes an imbalance between the internal free energy of the myofibril and that of unbound contractile proteins, initiating remodelling. The link between cross-bridge thermodynamics and myofibril remodelling proposed in this study may significantly advance current understanding of cardiac disease onset.

The Influence of Aortic Pulse Wave Velocity on Short-Term Functional Capacity in Patients with Mild Paravalvular Regurgitation Following Transcatheter Aortic Valve Implantation

INTRODUCTION

Recently, the clinical significance of mild paravalvular aortic regurgitation (PAR) has been evaluated and suggested that it can be predictor of clinical outcomes. In our study, we aimed to investigate the interaction of aortic pulse wave velocity (PWV) and mild PAR and their effects on the functional status of patients after transcatheter aortic valve implantation (TAVI).

METHODS

A total of 109 consecutive patients with symptomatic severe aortic stenosis were enrolled prospectively. After TAVI procedure, they were divided in to three groups according to PAR and PWV measurements. Patients without PAR were defined as the NonePAR group (n=60), patients with mild PAR and normal PWV were defined as the MildPAR-nPWV group (n=23), and patients with mild PAR and high PWV were defined as the MildPAR-hPWV group (n=26).

RESULTS

Compared with other groups, the MildPAR-hPWV group was older (P<0.001), hypertensive (P=0.015), and had a higher pulse pressure (P=0.018). In addition to PWV, this group had lower aortic regurgitation index (ARI) (P=0.010) and higher rate of New York Heart Association (NYHA) class II (at least) patients (P<0.001) in 30-day follow-up period. On multivariate regression analysis, the MildPARhPWV group (odds ratio=1.364, 95% confidence interval 1.221-1.843; P=0.011) as well as N-terminal-pro-brain natriuretic peptide levels and ARI were independently related with 30-day functional NYHA classification. However, NonePAR or MildPAR-nPWV group was not an independent predictor of early functional status.

CONCLUSION

It was concluded that high PWV may adversely affect early functional status in patients with mild PAR in contrast to normal values following TAVI.

Low-Risk Transcatheter Versus Surgical Aortic Valve Replacement - An Updated Meta-Analysis of Randomized Controlled Trials

OBJECTIVES

To perform a meta-analysis including all available randomized controlled trials (RCTs) to date comparing transcatheter aortic valve replacement (TAVR) to surgical aortic valve replacement (SAVR) in patients with severe aortic stenosis (AS) and low surgical risk.

BACKGROUND

Current guidelines recommend SAVR for patients with severe symptomatic AS and low surgical risk. A few RCTs have evaluated TAVR in low surgical risk patients but equipoise exists related to TAVR valve durability, paravalvular leak (PVL) and role of TAVR in younger, low surgical risk patients.

METHODS

Five databases were analyzed from January-2000 to March-2019 for RCTs comparing SAVR to TAVR in low-risk severe AS patients.

RESULTS

Four RCTs on low-risk TAVR patients with 2887 patients were included. Mean follow-up was ~24.1 ± 24 months. Early mortality was lower with TAVR compared to SAVR (RR: 0.44, 95% CI: 0.20-0.95, P = 0.038) whereas long-term mortality was similar (RR: 0.67, 95% CI: 0.39-1.14, P = 0.141). Both early and long-term stroke rates were similar. TAVR was associated with lower risk of atrial fibrillation, major bleeding, acute kidney injury (AKI) and rehospitalization, but higher rates of permanent pacemaker implantation (PPM) and moderate or severe PVL. There was no difference in major vascular complications, myocardial infarction, endocarditis, aortic valve gradients and valve area at follow-up.

CONCLUSIONS

In low-risk patients with severe AS, TAVR has a lower early mortality compared to SAVR with no difference in long-term mortality. Although complication rates varied between TAVR and SAVR, our study findings suggest that transfemoral-TAVR is an appropriate treatment option for severe symptomatic AS in patients with low surgical risk.

Left Ventricular Diastolic Dysfunction and Transcatheter Aortic Valve Replacement Outcomes: A Review

Aortic stenosis (AS) is the most common valvular disease that can lead to increased afterload, left ventricular (LV) remodeling, and myocardial fibrosis. We reviewed the literature addressing the impact of transcatheter aortic valve replacement (TAVR) on LV remodeling and patients' outcomes by elimination of AS-related high afterload. TAVR reduces afterload and improves LV remodeling recovery. However, myocardial fibrosis may not completely reverse after the TAVR. The LV diastolic dysfunction (LVDD) induced by AS is an independent predictor of post-TAVR mortality, and mortality increases with severity of LVDD. The impact of diastolic dysfunction on patient outcomes emerges at 30 days but continues to persist during mid-term follow-up. Based on severity of the baseline LVDD, some patients may tolerate post-TAVR aortic regurgitation (AR), but even minimal post-TAVR AR in patients with severe baseline LVDD can have an additive negative impact on survival. It is crucial to consider TAVR prior to development of advanced LVDD. Appropriate device selection and deployment technique are important in improvement of TAVR outcomes via elimination of AR.

Sex-Specific Outcomes After Transcatheter Aortic Valve Replacement: A Review of the Literature

Transcatheter aortic valve replacement (TAVR) is a safe and effective therapy for aortic valve replacement in patients ineligible for or at high risk for surgery. However, outcomes after TAVR based on an individual's sex remain to be fully elucidated. We searched PUBMED and EMBASE using the keywords: "transcatheter aortic valve replacement," "transcatheter aortic valve implantation," "sex differences," "gender," "sex characteristics" and collected information on baseline features, procedural characteristics, and postprocedural outcomes in women. Inclusion/exclusion resulted in 23 publications. Women had less preexisting comorbidities than men. Most studies reported better survival in women (range of hazard ratio [95% CI] = 0.27 [0.09-0.84] to 0.91 [0.75-1.10]). At 30 days, women also had more vascular complications (6-20% vs 2-14%) and higher bleeding rates (10-44% vs 8-25%). Stroke rates were similar at 30 days (women, 1-7%; men, 1-5%). This literature review showed better survival in women than men after TAVR. However, women had more vascular complications and bleeding; stroke rates were similar. These findings may partly be explained by fewer baseline comorbidities in women. These results should be interpreted with caution as most measures only include unadjusted percentages.

The role and clinical implications of diastolic dysfunction in aortic stenosis

Diastolic dysfunction in aortic stenosis results primarily from left ventricular hypertrophy and myocardial fibrosis due to chronically elevated left ventricular systolic pressure. Currently, diastolic dysfunction does not have an explicit clinical role in management of patients with aortic stenosis. Studies have shown that improvement in diastolic dysfunction follows left ventricular remodelling after aortic valve replacement and that it occurs gradually or incompletely. Retrospective studies suggest that advanced grades of diastolic dysfunction at baseline are associated with increased mortality and adverse events even after aortic valve replacement. Recent studies have also associated myocardial fibrosis, a hallmark of diastolic dysfunction, with worse outcomes. In addition, these results were independent of the degree of aortic stenosis or valve replacement. Indirect evidence of the role of diastolic dysfunction in aortic stenosis also comes from paradoxical low-flow, low-gradient aortic stenosis, where disproportionate left ventricular hypertrophy leads to underfilling of the left ventricle, low-flow state and is associated with worse prognosis. Lastly, a limited number of studies suggest that worse diastolic dysfunction at baseline is detrimental in patients who develop aortic regurgitation after transcatheteraortic valve replacement, due to superimposition of volume overload on a stiff left ventricle. Current major limitations in our understanding of the prognostic role of diastolic dysfunction are the lack of universally accepted classification schemes, its dependence on dynamic loading conditions and the lack of larger prospective studies.

Morphological features of the left atrial appendage in consecutive coronary computed tomography angiography patients with and without atrial fibrillation

The majority of intracardiac thrombi form in the left atrial appendage (LAA). Enlargement of this structure, together with certain morphological features, may indicate a predisposition to the formation of thrombi and subsequent cardioembolic stroke. Thus far, studies on LAA morphology have largely focused on those patients with atrial fibrillation (AF). Taking a different approach, we investigated the variation in LAA morphology in a consecutive patient population with and without AF. We evaluated 808 consecutive patients (529 females; mean age 52.5±9.9 years) who underwent coronary artery computed tomography angiography (CCTA), the majority of whom (749) had no history of AF. We assessed the length, lobe number, and morphological classification of their LAAs. Demographic data and medical histories were collated from medical records and then correlated with LAA morphology. The proportions of each of the four morphological classes of LAA for the overall vs. non-AF population were: WindSock, 62.3/61.5%; Cactus, 18.6/18.8%; ChickenWing, 10.0/10.0%; and CauliFlower, 9.2/9.6%. Age (p<0.001; r = 0.156) and female gender (p<0.001) were both found to be associated with an increased body surface area (BSA)-related LAA length. Male patients were more likely to manifest multi-lobed (p = 0.003) LAAs, and overweight patients with a greater number of multi-lobed LAA morphological classes (p = 0.010). No associations with morphological LAA features could be found for patients with diabetes, hypertension, or dyslipidemia. Nor did the size of the left atrium exhibit any correlation with BSA-related LAA length. In the overall and non-AF populations, aging and female gender were associated with longer BSA-indexed LAAs.

Aortic Regurgitation Generates a Kinematic Obstruction Which Hinders Left Ventricular Filling

An incompetent aortic valve (AV) results in aortic regurgitation (AR), where retrograde flow of blood into the left ventricle (LV) is observed. In this work, we parametrically characterized the detailed changes in intra-ventricular flow during diastole as a result of AR in a physiological in vitro left-heart simulator (LHS). The loss of energy within the LV as the level of AR increased was also assessed. The validated LHS consisted of an optically-clear, flexible wall LV and a modular AV holder. Two-component, planar, digital particle image velocimetry was used to visualize and quantify intra-ventricular flow. A large coherent vortical structure which engulfed the whole LV was observed under control conditions. In the cases with AR, the regurgitant jet was observed to generate a "kinematic obstruction" between the mitral valve and the LV apex, preventing the trans-mitral jet from generating a coherent vortical structure. The regurgitant jet was also observed to impinge on the inferolateral wall of the LV. Energy dissipation rate (EDR) for no, trace, mild, and moderate AR were found to be 1.15, 2.26, 3.56, and 5.99 W/m³, respectively. This study has, for the first time, performed an in vitro characterization of intra-ventricular flow in the presence of AR. Mechanistically, the formation of a "kinematic obstruction" appears to be the cause of the increased EDR (a metric quantifiable in vivo) during AR. EDR increases non-linearly with AR fraction and could potentially be used as a metric to grade severity of AR and develop clinical interventional timing strategies for patients.

A multicentre European registry to evaluate the Direct Flow Medical transcatheter aortic valve system for the treatment of patients with severe aortic stenosis

AIMS

Our aim was to assess the clinical outcomes of the Direct Flow Medical Transcatheter Aortic Valve System (DFM-TAVS), when used in routine clinical practice.

METHODS AND RESULTS

This is a prospective, open-label, multicentre, post-market registry of patients treated with DFM-TAVS according to approved commercial indications. Echocardiographic and angiographic data were evaluated by an independent core laboratory and adverse events were adjudicated and classified according to VARC-2 criteria by an independent clinical events committee. The primary endpoint was freedom from all-cause mortality at 30 days post procedure. Secondary endpoints included procedural, early safety and efficacy endpoints at 30 days. Two hundred and fifty patients with severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI) with the DFM-TAVS were enrolled in 21 European centres. The primary endpoint, freedom from all-cause mortality at 30 days, was met in 98% (245/250) of patients. Device success was 83.8%. Moderate or severe aortic regurgitation was reported in 3% of patients, and none/trace regurgitation in 73% of patients. Post-procedural permanent pacemaker implantation was performed in 30 patients (12.0%).

CONCLUSIONS

The DFM-TAVS was associated with good short-term outcomes in this real-world registry. The low pacemaker and aortic regurgitation rates confirm the advantages of this next-generation transcatheter heart valve (THV).

Transthoracic Echocardiography to Assess Aortic Regurgitation after TAVR: A Comparison with Periprocedural Transesophageal Echocardiography

Background: We aimed to compare periprocedural transesophageal echocardiography (TEE) with postprocedural transthoracic echocardiography (TTE) for the diagnosis of aortic regurgitation (AR). Methods and Results: TEE and TTE images of 163 transcatheter aortic valve replacement (TAVR) patients (mean age 81 ± 8 years; 56% men) were reviewed separately and blinded to each other as well as to all clinical data. The median time between TEE during TAVR (TEE/TAVR) and TTE was 4 days (IQR 2-10 days). After TAVR, 48% of the patients had at least trace AR by TEE, 56% by angiography and 67% by TTE. The majority of AR was paravalvular (78%). More patients were classified with mild-to-moderate AR by TTE than by TEE (44 vs. 22%, p < 0.01). When examining the 46 patients with AR by TTE which was not at TEE/TAVR, both systolic and diastolic blood pressure (SBP and DBP) were significantly higher during TTE than during TEE (mean ΔSBP = 9 ± 4 mm Hg and mean ΔDBP = 6 ± 2 mm Hg, p < 0.01 for both). No differences in BP between TEE and TTE were found among patients with no AR or among those who had AR in both studies. At a median follow-up of 185 days (IQR 39-424 days), the overall mortality was 17%, but this was not associated with the presence of AR on TTE or TEE. Conclusions: Patients' hemodynamic conditions may result in underdiagnosis of paravalvular regurgitation in periprocedural TEE. Our findings suggest that a postprocedural evaluation for AR by TTE could serve as a reasonable alternative to TEE for the evaluation of AR.

Percutaneous balloon aortic valvuloplasty in the era of transcatheter aortic valve implantation: a narrative review

The role of percutaneous balloon aortic valvuloplasty (BAV) in the management of severe symptomatic aortic stenosis has come under the spotlight following the development of the transcatheter aortic valve implantation (TAVI) technique. Previous indications for BAV were limited to symptom palliation and as a bridge to definitive therapy for patients undergoing conventional surgical aortic valve replacement (AVR). In the TAVI era, BAV may also be undertaken to assess the ‘therapeutic response’ of a reduction in aortic gradient in borderline patients often with multiple comorbidities, to assess symptomatic improvement prior to consideration of definitive TAVI intervention. This narrative review aims to update the reader on the current indications and practical techniques involved in undertaking a BAV procedure. In addition, a summary of the haemodynamic and clinical outcomes, as well as the frequently encountered procedural complications is presented for BAV procedures conducted during both the pre-TAVI and post-TAVI era.

A granular approach to improve reproducibility of the echocardiographic assessment of paravalvular regurgitation after TAVI

Paravalvular leak (PVL) after transcatheter aortic valve implantation (TAVI) is challenging to quantitate. Transthoracic echocardiography (TTE) is the main tool used for the assessment of PVL but is modestly reproducible. We sought to develop a reproducible echocardiographic approach to assess PVL in the post-TAVI setting. Four observers independently analyzed eleven parameters of PVL severity in 50 pre-discharge TTE studies performed after TAVI. The parameters included color-Doppler parameters [jet circumferential extent (CE) and planimetered vena contracta area in the short-axis view and jet breadth and qualitative features in the long-axis views], continuous-wave Doppler parameters [jet velocity time integral (VTI) and pressure half time (PHT)], quantitative Doppler parameters (regurgitation volume and fraction and effective regurgitant orifice area), aortic diastolic flow reversal and valve stent eccentricity. Intraclass correlation coefficient (ICC) and coefficient of variation (CV) for numerical parameters and kappa coefficient (κ) for categorical parameters were calculated for inter- and intra-observer comparisons. Inter-observer ICC was highest and CV lowest for CE (0.88 and 0.36), jet origin breadth (0.82 and 0.39), jet qualitative features in long-axis views (0.87 and 0.26), jet VTI (0.87 and 0.04) and PHT (0.73 and 0.10). Similar results were found in intra-observer comparisons. A 2-step granular approach combining the most reproducible parameters was used to grade PVL by the four observers. Inter-observer agreement was achieved in 86 % of cases (κ = 0.79). Combining color Doppler and continuous wave Doppler parameters in a granular algorithm yields excellent reproducibility of PVL assessment by TTE.

Prognostic Importance of Diastolic Dysfunction in Relation to Post Procedural Aortic Insufficiency in Patients Undergoing Transcatheter Aortic Valve Replacement

OBJECTIVES

We sought to examine whether baseline diastolic dysfunction (DD) is associated with increased mortality in patients who develop aortic insufficiency (AI) after transcatheter aortic valve replacement (TAVR).

BACKGROUND

Significant post-TAVR AI is associated with increased mortality, likely secondary to adverse hemodynamics secondary to volume overload and decreased LV compliance from chronic pressure overload. However, the effect of baseline DD on outcomes of patients with post-TAVR AI has not been studied.

METHODS

A total of 195 patients undergoing TAVR were included in the study. Patients with moderate-to-severe mitral stenosis, prior mitral valve replacement or atrial fibrillation were excluded. DD was classified at baseline by a 2-step approach as recommended by the American Society of Echocardiography while AI was evaluated 30 days post-TAVR. Follow up data up to 2 years post-TAVR was used in survival analysis.

RESULTS

Patients with severe baseline DD who developed ≥mild post-TAVR AI had increased mortality compared to all other patients (HR = 3.89, CI: 1.76-8.6, P = 0.001), which remained significant after adjusting for post-TAVR AI, pre-TAVR AI, baseline mitral regurgitation, ejection fraction, pulmonary artery pressure, creatinine clearance and history of stroke.

CONCLUSIONS

Even mild post-TAVR AI may have a negative impact on outcomes of patients with underlying severe DD. © 2016 Wiley Periodicals, Inc.

The hemodynamic effects of acute aortic regurgitation into a stiffened left ventricle resulting from chronic aortic stenosis

Acute aortic regurgitation (AR) post-chronic aortic stenosis is a prevalent phenomenon occurring in patients who undergo transcatheter aortic valve replacement (TAVR) surgery. The objective of this work was to characterize the effects of left ventricular diastolic stiffness (LVDS) and AR severity on LV performance. Three LVDS models were inserted into a physiological left heart simulator. AR severity was parametrically varied through four levels (ranging from trace to moderate) and compared with a competent aortic valve. Hemodynamic metrics such as average diastolic pressures (DP) and reduction in transmitral flow were measured. AR index was calculated as a function of AR severity and LVDS, and the work required to make up for lost volume due to AR was estimated. In the presence of trace AR, higher LVDS had up to a threefold reduction in transmitral flow (13% compared with 3.5%) and a significant increase in DP (2-fold). The AR index ranged from ∼42 to 16 (no AR to moderate AR), with stiffer LVs having lower values. To compensate for lost volume due to AR, the low, medium, and high LVDS models were found to require 5.1, 5.5, and 6.6 times more work, respectively. This work shows that the LVDS has a significant effect on the LV performance in the presence of AR. Therefore, the LVDS of potential TAVR patients should be assessed to gain an initial indication of their ability to tolerate post-procedural AR.

Transcatheter Aortic Valve Implantation in Lower-Risk Patients With Aortic Stenosis

Transcatheter aortic valve implantation underwent progressive improvements until it became the default therapy for inoperable patients, and a recommended therapy in high-risk operable patients with symptomatic severe aortic stenosis. In the lower-risk patient strata, a currently costly therapy that still has important complications with questionable durability is competing with the established effective and still-improving surgical replacement. This report tries to weigh the clinical evidence, the recent technical improvements, the durability, and the cost-effectiveness claims supporting the adoption of transcatheter aortic valve implantation in intermediate-low risk patients. The importance of appropriate patients’ risk stratification and a more comprehensive approach to estimate that risk are also emphasized in the present report.

Prediction of paravalvular leakage after transcatheter aortic valve implantation

Significant paravalvular leakage (PVL) after transcatheter aortic valve implantation (TAVI) is related to patient mortality. Predicting the development of PVL has focused on computed tomography (CT) derived variables but literature targeting CoreValve devices is limited, controversial, and did not make use of standardized echocardiographic methods. The study included 164 consecutive patients with severe aortic stenosis that underwent TAVI with a Medtronic CoreValve system©, with available pre-TAVI CT and pre-discharge transthoracic echocardiography. The predictive value for significant PVL of the CT-derived Agatston score, aortic annulus size and eccentricity, and “cover index” was assessed, according to both echocardiographic Valve Academic Research Consortium (VARC) criteria and angiographic Sellers criteria. Univariate predictors for more than mild PVL were the maximal diameter of the aortic annulus size (for both angiographic and echocardiographic assessment of PVL), cover index (for echocardiographic assessment of PVL only), and Agatston score (for both angiographic and echocardiographic assessment of PVL). The aortic annulus eccentricity index was not predicting PVL. At multivariate analysis, Agatston score was the only independent predictor for both angiographic and echocardiographic assessment of PVL. Agatston score is the only independent predictor of PVL regardless of the used imaging technique for the definition of PVL.

Incidence of strict versus nonstrict left bundle branch block after transcatheter aortic valve replacement

BACKGROUND

Up to one-third of patients diagnosed with left bundle branch block (LBBB) by conventional electrocardiographic (ECG) criteria are misdiagnosed. Strict LBBB shows decreased left ventricular pumping efficiency compared with nonstrict LBBB. However, no previous study has evaluated the frequency of strict LBBB after transcatheter aortic valve replacement (TAVR). The aim of this study was to determine the incidence of developing strict versus nonstrict LBBB after TAVR and test the hypothesis that preprocedure QRS duration does not predict strict LBBB but predicts development of nonstrict LBBB.

METHODS

All patients receiving TAVR between 4/2011 and 2/2013 (n = 71) with no preexisting bundle branch block or permanent pacemaker were included. Twelve-lead ECGs were acquired preprocedure and both 1-day and 1-month postprocedure. All ECGs were classified as strict LBBB, nonstrict LBBB, or no LBBB.

RESULTS

Sixty-eight patients had ECGs eligible for final analysis. On postprocedure day 1, 25 (37%) of 68 patients developed strict LBBB, and 2 patients (3%) developed nonstrict LBBB. At 1-month follow-up, the 2 patients diagnosed with nonstrict LBBB had resolved to normal, and 5 (20%) of 25 patients with strict LBBB had resolved to normal. Preprocedure QRS duration did not predict strict LBBB (P = .51). Because of the low incidence of nonstrict LBBB, QRS duration as a predictor of nonstrict LBBB could not be tested.

CONCLUSIONS

Almost all patients who developed evidence of LBBB after TAVR met the new strict criteria, indicating probable procedural injury to the left bundle branch. Preprocedural QRS duration did not predict the development of strict LBBB.

Influence of aortic regurgitation after TAVI on left ventricular filling pattern

BACKGROUND

Paravalvular aortic regurgitation after transcatheter aortic valve implantation is associated with a hemodynamic deterioration and a poor outcome. We aim to determine the early hemodynamic effect of paravalvular aortic regurgitation in relation with the change in the left ventricle filling pattern and to assess their clinical outcome.

MATERIAL AND METHODS

Eighty-two consecutive patients referred for transcatheter aortic valve implantation were included. Patients were classified according to the change in the left ventricular filling pattern, and significant paravalvular aortic regurgitation (grade ≥ 2) was reported. Follow-up and incidence of death and hospitalization for heart failure were reported.

RESULTS

Sixteen patients (19·5%) presented a worsening of left ventricular filling pattern. The incidence of significant paravalvular aortic regurgitation was higher in the group with a worsening of left ventricular filling pattern (56·3% vs. 19·7%; P = 0·009). In the multivariate analysis, the only variable significantly associated with the worsening of left ventricular filling pattern was the significant paravalvular aortic regurgitation (OR 4·84; 95% CI 1·23 - 19·1; P = 0·024). During the follow-up (642·5 days), there was a higher incidence of the endpoint of death or hospitalization for heart failure in the group with a worsening of left ventricular filling pattern (62·5% vs. 31·8%; P = 0·042) and a lower event-free survival rate (long rank test = 0·013).

CONCLUSIONS

The presence of a significant paravalvular aortic regurgitation is associated with a worsening in parameters of diastolic function. This finding should alert the cardiologist as patients with a worsening of left ventricular filling pattern present a higher incidence of paravalvular aortic regurgitation and a less favourable outcome.

Transcatheter aortic valve replacement for severe symptomatic aortic stenosis using a repositionable valve system: 30-day primary endpoint results from the REPRISE II study

BACKGROUND

Transcatheter aortic valve replacement provides results comparable to those of surgery in patients at high surgical risk, but complications can impact long-term outcomes. The Lotus valve, designed to improve upon earlier devices, is fully repositionable and retrievable, with a unique seal to minimize paravalvular regurgitation (PVR).

OBJECTIVES

The prospective, single-arm, multicenter REPRISE II study (REpositionable Percutaneous Replacement of Stenotic Aortic Valve Through Implantation of Lotus Valve System: Evaluation of Safety and Performance) evaluated the transcatheter valve system for treatment of severe symptomatic calcific aortic valve stenosis.

METHODS

Patients (n = 120; aortic annulus 19 to 27 mm) considered by a multidisciplinary heart team to be at high surgical risk received the valve transfemorally. The primary device performance endpoint, 30-day mean pressure gradient, was assessed by an independent echocardiographic core laboratory and compared with a pre-specified performance goal. The primary safety endpoint was 30-day mortality. Secondary endpoints included safety/effectiveness metrics per Valve Academic Research Consortium criteria.

RESULTS

Mean age was 84.4 years, 57% of the patients were female, and 76% were New York Heart Association functional class III/IV. Mean aortic valve area was 0.7 ± 0.2 cm(2). The valve was successfully implanted in all patients, with no cases of valve embolization, ectopic valve deployment, or additional valve implantation. All repositioning (n = 26) and retrieval (n = 6) attempts were successful; 34 patients (28.6%) received a permanent pacemaker. The primary device performance endpoint was met, because the mean gradient improved from 46.4 ± 15.0 mm Hg to 11.5 ± 5.2 mm Hg. At 30 days, the mortality rate was 4.2%, and the rate of disabling stroke was 1.7%; 1 (1.0%) patient had moderate PVR, whereas none had severe PVR.

CONCLUSIONS

REPRISE II demonstrates the safety and effectiveness of the Lotus valve in patients with severe aortic stenosis who are at high surgical risk. The valve could be positioned successfully with minimal PVR. (REPRISE II: REpositionable Percutaneous Replacement of Stenotic Aortic Valve Through Implantation of Lotus™ Valve System - Evaluation of Safety and Performance; NCT01627691).

Three-year outcomes after transcatheter aortic valve implantation with the CoreValve prosthesis

There is little known about the long-term results of the CoreValve prosthesis. The aim of this study was to assess the 3-year clinical and hemodynamic outcomes of the CoreValve prosthesis. One hundred fifty consecutive patients with severe aortic stenosis successfully underwent transcatheter aortic valve implantation (TAVI) with the CoreValve prosthesis. The primary study end point was death from any cause after TAVI. The secondary end points were defined as (1) cardiovascular death and (2) prosthesis-related mortality and morbidity. At 1 to 3 years, all-cause mortality rates were 25%, 32%, and 41%, respectively, and cardiovascular mortality rates were 14%, 21%, and 27%, respectively. Before TAVI, 95% of patients were in New York Heart Association class III or IV. Of the surviving patients, rates of New York Heart Association class III or IV at 1 to 3 years were 33%, 39%, and 38%, respectively. There was an annual decrease of the valve area of approximately 0.1 cm². Aortic restenosis occurred in 2 patients. Moderate or severe aortic regurgitation (AR) occurred in 15% of patients immediately after TAVI. Twenty patients (13%) had a slight worsening of AR within 3 years. New severe AR did not occur. The incidence of prosthesis-related endocarditis was 0.66% per year. Overall, 7 patients (incidence of 1.5% per year) had a clinically relevant problem of the prosthesis. In conclusion, TAVI with the CoreValve prosthesis had favorable effects on symptoms and outcomes even after 3 years. These results are clouded by side effects, such as AR and prosthesis-related mortality and morbidity.