Bioprosthetic Aortic Valve Hemodynamics: Definitions, Outcomes, and Evidence Gaps: JACC State-of-the-Art Review

Examining the typical hemodynamic performance of nearly 3000 modern surgical aortic bioprostheses

OBJECTIVES

The objective of this analysis was to assess the normal haemodynamic performance of contemporary surgical aortic valves at 1 year postimplant in patients undergoing surgical aortic valve replacement for significant valvular dysfunction. By pooling data from 4 multicentre studies, this study will contribute to a better understanding of the effectiveness of surgical aortic valve replacement procedures, aiding clinicians and researchers in making informed decisions regarding valve selection and patient management.

METHODS

Echocardiograms were assessed by a single core laboratory. Effective orifice area, dimensionless velocity index, mean aortic gradient, peak aortic velocity and stroke volume were evaluated.

RESULTS

The cohort included 2958 patients. Baseline age in the studies ranged from 70.1 ± 9.0 to 83.3 ± 6.4 years, and Society of Thoracic Surgeons risk of mortality was 1.9 ± 0.7 to 7.5 ± 3.4%. Twenty patients who had received a valve model implanted in fewer than 10 cases were excluded. Ten valve models (all tissue valves; n = 2938 patients) were analysed. At 1 year, population mean effective orifice area ranged from 1.46 ± 0.34 to 2.12 ± 0.59 cm2, and dimensionless velocity index, from 0.39 ± 0.07 to 0.56 ± 0.15. The mean gradient ranged from 8.6 ± 3.4 to 16.1 ± 6.2 mmHg with peak aortic velocity of 1.96 ± 0.39 to 2.65 ± 0.47 m/s. Stroke volume was 75.3 ± 19.6 to 89.8 ± 24.3 ml.

CONCLUSIONS

This pooled cohort is the largest to date of contemporary surgical aortic valves with echocardiograms analysed by a single core lab. Overall haemodynamic performance at 1 year ranged from good to excellent. These data can serve as a benchmark for other studies and may be useful to evaluate the performance of bioprosthetic surgical valves over time.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02088554, NCT02701283, NCT01586910 and NCT01531374.

Self-Expanding or Balloon-Expandable TAVR in Patients with a Small Aortic Annulus

BACKGROUND

Patients with severe aortic stenosis and a small aortic annulus are at risk for impaired valvular hemodynamic performance and associated adverse cardiovascular clinical outcomes after transcatheter aortic-valve replacement (TAVR).

METHODS

We randomly assigned patients with symptomatic severe aortic stenosis and an aortic-valve annulus area of 430 mm2 or less in a 1:1 ratio to undergo TAVR with either a self-expanding supraannular valve or a balloon-expandable valve. The coprimary end points, each assessed through 12 months, were a composite of death, disabling stroke, or rehospitalization for heart failure (tested for noninferiority) and a composite end point measuring bioprosthetic-valve dysfunction (tested for superiority).

RESULTS

A total of 716 patients were treated at 83 sites in 13 countries (mean age, 80 years; 87% women; mean Society of Thoracic Surgeons Predicted Risk of Mortality, 3.3%). The Kaplan-Meier estimate of the percentage of patients who died, had a disabling stroke, or were rehospitalized for heart failure through 12 months was 9.4% with the self-expanding valve and 10.6% with the balloon-expandable valve (difference, -1.2 percentage points; 90% confidence interval [CI], -4.9 to 2.5; P<0.001 for noninferiority). The Kaplan-Meier estimate of the percentage of patients with bioprosthetic-valve dysfunction through 12 months was 9.4% with the self-expanding valve and 41.6% with the balloon-expandable valve (difference, -32.2 percentage points; 95% CI, -38.7 to -25.6; P<0.001 for superiority). The aortic-valve mean gradient at 12 months was 7.7 mm Hg with the self-expanding valve and 15.7 mm Hg with the balloon-expandable valve, and the corresponding values for additional secondary end points through 12 months were as follows: mean effective orifice area, 1.99 cm2 and 1.50 cm2; percentage of patients with hemodynamic structural valve dysfunction, 3.5% and 32.8%; and percentage of women with bioprosthetic-valve dysfunction, 10.2% and 43.3% (all P<0.001). Moderate or severe prosthesis-patient mismatch at 30 days was found in 11.2% of the patients in the self-expanding valve group and 35.3% of those in the balloon-expandable valve group (P<0.001). Major safety end points appeared to be similar in the two groups.

CONCLUSIONS

Among patients with severe aortic stenosis and a small aortic annulus who underwent TAVR, a self-expanding supraannular valve was noninferior to a balloon-expandable valve with respect to clinical outcomes and was superior with respect to bioprosthetic-valve dysfunction through 12 months. (Funded by Medtronic; SMART ClinicalTrials.gov number, NCT04722250.).

Guidelines for the Evaluation of Prosthetic Valve Function With Cardiovascular Imaging: A Report From the American Society of Echocardiography Developed in Collaboration With the Society for Cardiovascular Magnetic Resonance and the Society of Cardiovascular Computed Tomography

In patients with significant cardiac valvular disease, intervention with either valve repair or valve replacement may be inevitable. Although valve repair is frequently performed, especially for mitral and tricuspid regurgitation, valve replacement remains common, particularly in adults. Diagnostic methods are often needed to assess the function of the prosthesis. Echocardiography is the first-line method for noninvasive evaluation of prosthetic valve function. The transthoracic approach is complemented with two-dimensional and three-dimensional transesophageal echocardiography for further refinement of valve morphology and function when needed. More recently, advances in computed tomography and cardiac magnetic resonance have enhanced their roles in evaluating valvular heart disease. This document offers a review of the echocardiographic techniques used and provides recommendations and general guidelines for evaluation of prosthetic valve function on the basis of the scientific literature and consensus of a panel of experts. This guideline discusses the role of advanced imaging with transesophageal echocardiography, cardiac computed tomography, and cardiac magnetic resonance in evaluating prosthetic valve structure, function, and regurgitation. It replaces the 2009 American Society of Echocardiography guideline on prosthetic valves and complements the 2019 guideline on the evaluation of valvular regurgitation after percutaneous valve repair or replacement.

Echocardiographic Versus Invasive Aortic Valve Gradients in Different Clinical Scenarios

BACKGROUND

The role of echocardiography in deriving transvalvular mean gradients from transaortic velocities in aortic stenosis (AS) and in structural valve degeneration (SVD) is well established. However, reports following surgical aortic valve replacement, post-transcatheter aortic valve replacement (TAVR), and valve-in-valve-TAVR (ViV-TAVR) have cautioned against the use of echocardiography-derived mean gradients to assess normal functioning bioprosthesis due to discrepancy compared with invasive measures in a phenomenon called discordance.

METHODS

In a multicenter study, intraprocedural echocardiographic and invasive mean gradients in AS, SVD, post-native TAVR, and post-ViV-TAVR were compared, when obtained concomitantly, and discharge echocardiographic gradients were recorded. Absolute discordance (intraprocedural echocardiographic - invasive mean gradient) and percent discordance (intraprocedural echocardiographic - invasive mean gradient/echocardiographic mean gradient) were calculated. Multivariable regression analysis was performed to determine variables independently associated with elevated postprocedure invasive gradients ≥20 mm Hg, absolute discordance >10 mm Hg, and discharge echocardiographic mean gradient ≥20 mm Hg.

RESULTS

A total of 5,027 patients were included in the registry: 4,725 native TAVR and 302 ViV-TAVR. Intraprocedural concomitant echocardiographic and invasive mean gradients were obtained pre-TAVR in AS (n = 2,418), pre-ViV-TAVR in SVD (n = 101), in post-ViV-TAVR (n = 77), and in post-TAVR (n = 823). Echocardiographic and invasive mean gradients demonstrated strong correlation (r = 0.69) and agreement (bias, 0.11; 95% CI, -0.4-0.62) in AS, moderate correlation (r = 0.56) and agreement (bias, 1.08; 95% CI, -2.53 to 4.59) in SVD, moderate correlation (r = 0.61) and weak agreement (bias, 6.47; 95% CI, 5.08-7.85) post-ViV-TAVR, and weak correlation (r = 0.18) and agreement (bias, 3.41; 95% CI, 3.16-3.65) post-TAVR. Absolute discordance occurs primarily in ViV-TVR and is not explained by sinotubular junction size and increases with increasing echocardiographic mean gradient. Percent discordance in AS and SVD (1.3% and 4%, respectively) was lower compared with post-TAVR/ViV-TAVR (66.7% and 100%, respectively). Compared with self-expanding valves, balloon expanding valves were independently associated with elevated discharge echocardiographic but lower invasive mean gradient (odds ratio = 3.411, 95% CI, 1.482-7.852, P = .004; vs odds ratio = 0.308, 95% CI, 0.130-0.731, P = .008, respectively).

CONCLUSIONS

Post-TAVR/ViV-TAVR, echocardiography is discordant from invasive mean gradients, and absolute discordance increases with increasing echocardiographic mean gradient and is not explained by sinotubular junction size. Percent discordance is significantly higher post-TAVR/ViV-TAVR than in AS and SVD. Post-TAVR/ViV-TAVR, poor correlation and wide limits of agreement suggest echocardiographic and invasive mean gradients may not be used interchangeably and a high residual echocardiographic mean gradient should be confirmed invasively before considering any additional procedure to "correct" the gradient. Transcatheter aortic valve replacement valve types have variable impact on echocardiographic and invasive mean gradients.

Prosthesis-patient mismatch after transcatheter implantation of contemporary balloon-expandable and self-expandable valves in small aortic annuli

BACKGROUND

Evidence of clinical impact of PPM after TAVI is conflicting and might vary according to the type of valve implanted.

AIMS

To assess the clinical impact of prosthesis-patient mismatch (PPM) after transcatheter aortic valve implantation (TAVI) with balloon-expandable (BEV) and self-expandable valves (SEV) in patients with small annuli.

METHODS

TAVI-SMALL 2 enrolled 628 patients in an international retrospective registry, which included patients with severe aortic stenosis and small annuli (annular perimeter <72 mm or area <400 mm2 ) treated with transfemoral TAVI at 16 high-volume centers between 2011 and 2020. Analyses were performed comparing patients with less than moderate (n = 452), moderate (n = 138), and severe PPM (n = 38). Primary endpoint was incidence of all-cause mortality. Predictors of all-cause mortality and PPM were investigated.

RESULTS

At a median follow-up of 380 days (interquartile range: 210-709 days), patients with severe PPM, but not moderate PPM, had an increased risk of all-cause mortality when compared with less than moderate PPM (log-rank p = 0.046). Severe PPM predicted all-cause mortality in patients with BEV (hazard ratio [HR]: 5.20, 95% confidence interval [CI]: 1.27-21.2) and intra-annular valves (IAVs, HR: 4.23, 95% CI: 1.28-14.02), and it did so with borderline significance in the overall population (HR: 2.89, 95% CI: 0.95-8.79). Supra-annular valve (SAV) implantation was the only predictor of severe PPM (odds ratio: 0.33, 95% CI: 0.13-0.83).

CONCLUSIONS

Patients with small aortic annuli and severe PPM after TAVI have an increased risk of all-cause mortality at early term follow-up, especially after IAV or BEV implantation. TAVI with SAV protected from severe PPM.

Optimizing aortic valve prosthesis selection in patients with obesity: Institutional experience with multidisciplinary perspective

BACKGROUND

Aortic valve diseases are life-threatening conditions with increasing prevalence worldwide. Risk factors include gender, age, hypertension, dyslipidemia, and type 2 diabetes. Obesity is closely related to these risk factors and has been linked to a higher risk of developing aortic valve diseases. However, there is no specific guideline for managing aortic valve disease in patients with obesity, and the choice of valve type remains uncertain.

METHODS

A total of 130 patients with obesity who met the inclusion criteria underwent surgical aortic valve replacement. The patients were divided into two groups based on the type of prosthesis used. Among the study cohort, 50 patients received a bioprosthetic valve, while 80 patients received a mechanical valve. We compared these groups in terms of perioperative characteristics and follow-up results. Statistical significance was determined using a p-value threshold of 0.05.

RESULTS

There were no significant differences in age, gender, body mass index, or cardiac comorbidities between the two groups. Preoperative blood results and echo findings also showed no significant differences. Intraoperative characteristics and postoperative outcomes, including mortality and acute kidney injury, did not differ significantly between the groups. In addition, BHVG patients had shorter ICU stays compared to MHVG patients without significance.

CONCLUSION

Deliberate consideration is crucial when selecting valves for obese patients, particularly those with class II obesity. This is due to the potential influence of obesity on valve types, as well as the need to account for the possibility of bariatric surgery and its potential effects.

Discrepancy between invasive and echocardiographic transvalvular gradient after TAVI: Insights from the LAPLACE-TAVI registry

BACKGROUND

Echocardiography-based transvalvular mean pressure gradient (ECHO-mPG) used to assess the forward valve function and structural valve deterioration could overestimate the true pressure gradient. This study evaluated the discrepancy between invasive and ECHO-mPG after transcatheter aortic valve implantation (TAVI) with respective valve type and size, its impact on a device success criterion, and predictors of a pressure discrepancy.

METHODS

We analyzed 645 patients registered in a multicenter TAVI registry (balloon-expandable valve [BEV]: 500; self-expandable valve [SEV]: 145). The invasive transvalvular mPG was measured after valve implantation using two Pigtail catheters (CATH-mPG), while the ECHO-mPG was measured within 48 h after TAVI. Pressure recovery (PR) was calculated using the following formula: ECHO-mPG × effective orifice area (EOA)/ascending aortic area (AoA) × (1 - EOA/AoA).

RESULTS

ECHO-mPG was weakly correlated with (r = 0.29, p < 0.0001), and consistently overestimated CATH-mPG in both BEV and SEV, and respective valve sizes. The magnitude of the discrepancy was larger for BEV than SEV (p < 0.001) and smaller valves (p < 0.001). After the correction of PR using the above formula, the pressure discrepancy remained for BEV (p < 0.001) but not SEV (p = 0.10). The proportion of patients with an ECHO-mPG > 20 mmHg decreased from 7.0% to 1.6% after correction (p < 0.0001). Among the baseline and procedural variables, post-procedural ejection fraction, BEV versus SEV, and smaller valves were associated with a larger discrepancy in mPG.

CONCLUSIONS

ECHO-mPG could be overestimated after TAVI, especially in patients with a smaller BEV. A higher ejection fraction, BEV, and smaller valves were predictors of a pressure discrepancy between CATH- and ECHO-mPG.

Hemodynamic Performance of Transcatheter Aortic Valves: A Comprehensive Review

Transcatheter aortic valve implantation (TAVI) is a widely adopted treatment option for patients with severe aortic stenosis. Its popularity has grown significantly in recent years due to advancements in technology and imaging. As TAVI use is increasingly expanded to younger patients, the need for long-term assessment and durability becomes paramount. This review aims to provide an overview of the diagnostic tools to evaluate the hemodynamic performance of aortic prosthesis, with a special focus on the comparison between transcatheter and surgical aortic valves and between self-expandable and balloon-expandable valves. Moreover, the discussion will encompass how cardiovascular imaging can effectively detect long-term structural valve deterioration.

Effect of Prosthesis-Patient Mismatch on Long-Term Clinical Outcomes After Bioprosthetic Aortic Valve Replacement

BACKGROUND

Prosthesis-patient mismatch (PPM) is common following surgical aortic valve replacement (SAVR).

OBJECTIVES

The purpose of this study was to quantify the impact of PPM on all-cause mortality, heart failure hospitalization, and reintervention following bioprosthetic SAVR.

METHODS

This observational nationwide cohort study from SWEDEHEART (Swedish Web system for Enhancement and Development of Evidence based care in Heart disease Evaluated According to Recommended Therapies) and other national registers included all patients who underwent primary bioprosthetic SAVR in Sweden from 2003 to 2018. PPM was defined according to the Valve Academic Research Consortium 3 criteria. Outcomes were all-cause mortality, heart failure hospitalization, and aortic valve reintervention. Regression standardization was used to account for intergroup differences and to estimate cumulative incidence differences.

RESULTS

We included 16,423 patients (no PPM: 7,377 [45%]; moderate PPM: 8,502 [52%]; and severe PPM: 544 [3%]). After regression standardization, the cumulative incidence of all-cause mortality at 10 years was 43% (95% CI: 24%-44%) in the no PPM group compared with 45% (95% CI: 43%-46%) and 48% (95% CI: 44%-51%) in the moderate and severe PPM groups, respectively. The survival difference at 10 years was 4.6% (95% CI: 0.7%-8.5%) and 1.7% (95% CI: 0.1%-3.3%) in no vs severe PPM and no vs moderate PPM, respectively. The difference in heart failure hospitalization at 10 years was 6.0% (95% CI: 2.2%-9.7%) in severe vs no PPM. There was no difference in aortic valve reintervention in patients with or without PPM.

CONCLUSIONS

Increasing grades of PPM were associated with long-term mortality, and severe PPM was associated with increased heart failure. Moderate PPM was common, but the clinical significance may be negligible because the absolute risk differences in clinical outcomes were small.

Editor-in-Chief's Top Picks From 2022

Each week, I record audio summaries for every paper in JACC, as well as an issue summary. This process has become a true labor of love due to the time they require, but I am motivated by the sheer number of listeners (16 million plus), and it has allowed me to familiarize myself with every paper that we publish. Thus, I have selected the top 100 papers (both Original Investigations and Review Articles) from distinct specialties each year. In addition to my personal choices, I have included papers that have been the most accessed or downloaded on our websites, as well as those selected by the JACC Editorial Board members. In order to present the full breadth of this important research in a consumable fashion, we will present these abstracts in this issue of JACC, as well as their Central Illustrations and podcasts. The highlights comprise the following sections: Basic & Translational Research, Cardiac Failure & Myocarditis, Cardiomyopathies & Genetics, Cardio-Oncology, Congenital Heart Disease, Coronary Disease & Interventions, Coronavirus, Hypertension, Imaging, Metabolic & Lipid Disorders, Neurovascular Disease & Dementia, Promoting Health & Prevention, Rhythm Disorders & Thromboembolism, and Valvular Heart Disease.^1-100.

Standardized Definitions for Bioprosthetic Valve Dysfunction Following Aortic or Mitral Valve Replacement: JACC State-of-the-Art Review

Bioprosthetic valve dysfunction (BVD) and bioprosthetic valve failure (BVF) may be caused by structural or nonstructural valve dysfunction. Both surgical and transcatheter bioprosthetic valves have limited durability because of structural valve deterioration. The main objective of this summary of experts participating in a virtual workshop was to propose standardized definitions for nonstructural and structural BVD and BVF following aortic or mitral biological valve replacement with the goal of facilitating research reporting and implementation of these terms in clinical practice. Definitions of structural BVF, based on valve reintervention or death, underestimate the true incidence of BVF. However, definitions solely based on the presence of high transprosthetic gradient at a given echocardiogram during follow-up overestimate the incidence of structural BVD and BVF. Definitions of aortic or mitral structural BVD must therefore include the confirmation by imaging of permanent structural changes to the leaflets alongside evidence of deterioration in valve hemodynamic function at echocardiography follow-up.