Mitral Regurgitation in Low-Flow, Low-Gradient Aortic Stenosis Patients Undergoing TAVR

Mitral regurgitation carries greater prognostic significance than mitral stenosis in patients undergoing transcatheter aortic valve replacement

AIMS

This study assessed the outcomes of concomitant mitral valve disease and severe aortic stenosis in patients undergoing transcatheter aortic valve replacement (TAVR).

METHODS

Echocardiographic data of 813 patients with severe aortic stenosis undergoing transfemoral TAVR were collected, and clinical outcomes were analyzed for individuals with mitral stenosis and mitral regurgitation.

RESULTS

The final cohort includes 788 patients with severe calcific aortic stenosis. Among single parameters of mitral stenosis, a smaller baseline mitral valve area (MVA) by the continuity equation and higher postprocedural mean mitral gradients (MMG) were associated with an increased risk of death at 1 year (P-values 0.02 and <0.01, respectively), but no correlation with outcomes was demonstrated after multivariate adjustment for major prognosticators. Mitral stenosis (based on MVA + MMG) was not associated with complications or mortality. Mitral regurgitation was present in 94.6% of the population at baseline and regressed by at least one grade post-TAVR in 28% of the patients. The improvement in mitral regurgitation was associated with a greater prosthetic effective orifice area (P-value 0.03). Significant (at least moderate) residual mitral regurgitation was correlated with short-term complications and shown to be an independent predictor of 1-year mortality (P-value 0.02, odds ratio (OR) 5.37, confidence interval 1.34-21.5).

CONCLUSION

Mitral regurgitation has a greater impact on TAVR patients than mitral stenosis as assessed by functional methods.

Combined Significant Aortic Stenosis and Mitral Regurgitation: Challenges in Timing and Type of Intervention

In this narrative review, we aim to summarize the literature surrounding the assessment and management of the common, yet understudied combination of aortic stenosis (AS) and mitral regurgitation (MR), the components of which are complexly inter-related and interdependent from diagnostic, prognostic, and therapeutic perspectives. The hemodynamic interdependency of AS and MR confounds the assessment of the severity of each valve disease, thus underscoring the importance of a multimodal approach integrating valvular and extravalvular indicators of severity. A large body of literature suggests that baseline MR is associated with reduced survival post aortic valve (AV) intervention and that regression of MR post-AV intervention confers a mortality benefit. Functional MR is more likely to regress after AV intervention than primary MR. The respective natural courses of the 2 valve diseases are not synchronized; therefore, significant AS and MR at or above the respective threshold for intervention might not coincide. Surgery is primarily a 1-stop-shop procedure because of a considerable perioperative risk of repeat interventions, whereas transcatheter treatment modalities allow for a more tailored timing of intervention with reassessment of concomitant MR after AV replacement and a potential staged intervention in the absence of MR regression. In summary, AS and MR, when combined, are interlaced into a complex hemodynamic, diagnostic, and prognostic synergy, with important therapeutic implications. Contemporary approaches should consider stepwise intervention by exploiting the advantage of transcatheter options. However, evidence is needed to demonstrate the efficacy of different timing and therapeutic options.

Low-flow in aortic valve stenosis patients with reduced ejection fraction does not depend on left ventricular function

BACKGROUND

Patients with severe aortic stenosis (AS) and reduced left ventricular ejection fraction (LVEF) can be distinguished into high- (HG) and low-gradient (LG) subgroups. However, less is known about their characteristics and underlying (pathophysiological) hemodynamic mechanisms.

METHODS

98 AS patients with reduced LVEF were included. Subgroup characteristics were analyzed by a multimodal approach using clinical and histological data, next-generation sequencing (NGS) and applying echocardiography as well as cardiovascular magnetic resonance (CMR) imaging. Biopsy samples were analyzed with respect to fibrosis and mRNA expression profiles.

RESULTS

40 patients were classified as HG-AS and 58 patients as LG-AS. Severity of AS was comparable between the subgroups. Comparison of both subgroups revealed no differences in LVEF (p = 0.1), LV mass (p = 0.6) or end-diastolic LV diameter (p = 0.12). Neither histological (HG: 23.2% vs. LG: 25.6%, p = 0.73) and circulating biomarker-based assessment (HG: 2.6 ± 2.2% vs. LG: 3.2 ± 3.1%; p = 0.46) of myocardial fibrosis nor global gene expression patterns differed between subgroups. Mitral regurgitation (MR), atrial fibrillation (AF) and impaired right ventricular function (MR: HG: 8% vs. LG: 24%; p < 0.001; AF: HG: 30% vs. LG: 51.7%; p = 0.03; RVSVi: HG 36.7 vs. LG 31.1 ml/m2, p = 0.045; TAPSE: HG 20.2 vs. LG 17.3 mm, p = 0.002) were more frequent in LG-AS patients compared to HG-AS. These pathologies could explain the higher mortality of LG vs. HG-AS patients.

CONCLUSION

In patients with low-flow severe aortic stenosis, low transaortic gradient and cardiac output are not primarily due to LV dysfunction or global changes in gene expression, but may be attributed to other additional cardiac pathologies like mitral regurgitation, atrial fibrillation or right ventricular dysfunction. These factors should also be considered during planning of aortic valve replacement.

Impact of route of access and stenosis subtype on outcome after transcatheter aortic valve replacement

Introduction

Previous analyses have reported the outcomes of transcatheter aortic valve replacement (TAVR) for patients with low-flow, low-gradient (LFLG) aortic stenosis (AS), without stratifying according to the route of access. Differences in mortality rates among access routes have been established for high-gradient (HG) patients and hypothesized to be even more pronounced in LFLG AS patients. This study aims to compare the outcomes of patients with LFLG or HG AS following transfemoral (TF) or transapical (TA) TAVR.

Methods

A total of 910 patients, who underwent either TF or TA TAVR with a median follow-up of 2.22 (IQR: 1.22-4.03) years, were included in this multicenter cohort study. In total, 146 patients (16.04%) suffered from LFLG AS. The patients with HG and LFLG AS were stratified according to the route of access and compared statistically.

Results

The operative mortality rates of patients with HG and LFLG were found to be comparable following TF access. The operative mortality rate was significantly increased for patients who underwent TA access [odds ratio (OR): 2.91 (1.54-5.48), p = 0.001] and patients with LFLG AS [OR: 2.27 (1.13-4.56), p = 0.02], which could be corroborated in a propensity score-matched subanalysis. The observed increase in the risk of operative mortality demonstrated an additive effect [OR for TA LFLG: 5.45 (2.35-12.62), p < 0.001]. LFLG patients who underwent TA access had significantly higher operative mortality rates (17.78%) compared with TF LFLG (3.96%, p = 0.016) and TA HG patients (6.36%, p = 0.024).

Conclusions

HG patients experienced a twofold increase in operative mortality rates following TA compared with TF access, while LFLG patients had a fivefold increase in operative mortality rates. TA TAVR appears suboptimal for patients with LFLG AS. Prospective studies should be conducted to evaluate alternative options in cases where TF is not possible.

Prognostic Impact of Mitral Regurgitation Before and After Transcatheter Aortic Valve Replacement in Patients With Severe Low-Flow, Low-Gradient Aortic Stenosis

Background There is little evidence about the prognostic role of mitral regurgitation (MR) in patients with low-flow, low-gradient aortic stenosis undergoing transcatheter aortic valve replacement (TAVR). The aim of this study was to assess the prevalence and outcome implications of MR severity in patients with low-flow, low-gradient aortic stenosis undergoing TAVR, and to evaluate whether MR improvement after TAVR could influence clinical outcome. Methods and Results This study included consecutive patients with low-flow, low-gradient aortic stenosis undergoing TAVR at 2 Italian high-volume centers. The study population was categorized according to the baseline MR severity and to the presence of MR improvement at discharge. The primary outcome was the composite of all-cause death and hospitalization for worsening heart failure up to 1 year. The study included 268 patients; 57 (21%) patients showed MR >2+. Patients with MR >2+ showed a lower 1-year survival free from the primary outcome (P<0.001), all-cause death (P<0.001), and heart failure hospitalization (P<0.001) compared with patients with MR ≤2+. At multivariable analysis, baseline MR >2+ was an independent predictor of the primary outcome (P<0.001). Among patients with baseline MR >2+, MR improvement was reported in 24 (44%) cases after TAVR. The persistence of MR was associated with a significantly reduced survival free from the primary outcome, all-cause death, and heart failure hospitalization up to 1 year. Conclusions In this study, the presence of moderately severe to severe MR in patients with low-flow, low-gradient aortic stenosis undergoing TAVR portends a worse clinical outcome at 1 year. TAVR may improve MR severity in nearly half of the patients, resulting in a potential outcome benefit after discharge.

Prevalence and clinical associations of mitral and aortic regurgitation in patients with aortic stenosis

BACKGROUND

Most guidelines directing clinicians to manage valve disease are directed at single valve lesions. Limited data exists to direct our understanding of how concomitant valve disease impacts the left ventricle (LV).

METHODS

We identified 2817 patients with aortic stenosis (AS) from the echocardiography laboratory database between September 2012 and June 2018 who had a LV ejection fraction (EF) ≥50%. LV mass, LV mass index, LV systolic pressure (systolic blood pressure + peak aortic gradient). Covariates were collected from the electronic medical record. Multi-variate analysis of covariance was used to generate adjusted comparisons.

RESULTS

Our population was 66% female, 17% African-American with a mean age of 65 years. Of note, 7.3% were noted to have significant (moderate/severe) aortic regurgitation (AR), and 11% had significant (moderate/severe) mitral regurgitation (MR). Adjusting for covariates at different levels, significant MR had a much stronger association with heart failure compared to those with significant AR (p < .001 vs. p = .313, respectively) at all levels of adjustment. Both significant mitral and AR exhibited an association with increasing left ventricular mass, even with adjustment for baseline demographics and clinical features (p < .001 vs. p = .007, respectively).

CONCLUSION

In patients with AS, 16% also experience at least moderate MR or AR. Further, significant MR has a stronger association with heart failure than significant AR, even though both increase left ventricular mass. Those with moderate AS and significant MR or AR experience similar or higher levels of heart failure compared to severe AS without regurgitation. Mixed valve disease merits further studies to direct longitudinal management.

Impact of Transcatheter Aortic Valve Implantation Among Patients With Co-existing Mild to Moderate Mitral Regurgitation

A subset of patients with severe aortic stenosis (AS) who are who underwent transcatheter aortic valve implantation (TAVI) also has mitral regurgitation (MR). Clinical outcomes in these patients with combined MR and AS have varied. The purpose of this study was to assess clinical outcomes and echocardiographic outcomes after TAVI in patients with preprocedural MR. A retrospective chart review from March 2018 to June 2020 identified all TAVI patients. Patients were assigned an MR class of mild, moderate, or severe based upon pre-TAVI transthoracic echocardiogram (TTE). Patients were excluded if they were discharged from the hospital and did not have a 6-month follow-up after TAVI. Clinical outcomes at 6 months included all-cause mortality, major adverse cardiovascular events, clinically significant bleeding, changes in ejection fraction (EF) category, and changes in MR severity. Of 118 included patients (age 76 ± 10 years, 79% male, 46% White), 33% had MR, with 26% being mild and 7% moderate MR. Before TAVI, AS + MR patients were more likely to have a reduced EF (<50%) by category compared with those with AS only (33.3% vs 8.8%, p = 0.01) but were more likely to show an increase in EF by category after TAVI (19.4% vs 5.5%, p = 0.039). No significant differences were observed between the 2 groups in terms of all-cause mortality (12.8 vs 5.1%, p = 0.14), major adverse cardiovascular events (17.9 vs 8.9%, p = 0.15), or clinically significant bleeding (10.3 vs 6.3%, p = 0.45). Patients with AS and co-existing MR experienced similar clinical outcomes at 6 months to those with AS only after TAVI. They were more likely to show increases in EF category 6 months after valve implantation. Our results support the conclusion that in addition to treating the aortic valve, TAVI also potentially benefits left ventricular function in the setting of mild or moderate MR.

Risk Factors for Hospital Readmission Post-Transcatheter Aortic Valve Implantation in the Contemporary Era: A Systematic Review

Background

Despite transcatheter aortic valve implantation (TAVI) becoming a widely accepted therapeutic option for the management of aortic stenosis, post-procedure readmission rates remain high. Rehospitalization is associated with negative patient outcomes, as well as increased healthcare costs, and has therefore been identified as an important target for quality improvement. Strategies to reduce the post-TAVI readmission rate are needed but require the identification of patients at high risk for rehospitalization. Our systematic review aims to identify predictors of post-procedure readmission in patients eligible for TAVI.

Methods

We conducted a comprehensive search of the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases for the time period from 2015 to the present for articles evaluating risk factors for rehospitalization post-TAVI with a follow-up period of at least 30 days in adults age ≥ 70 years with aortic stenosis. The quality of included studies was evaluated using the Newcastle-Ottawa Scale. We present the results as a qualitative narrative review.

Results

We identified 49 studies involving 828,528 patients. Post-TAVI readmission is frequent, and rates vary (14.9% to 54.3% at 1 year). The most-frequent predictors identified for both 30-day and 1-year post-TAVI readmission are atrial fibrillation, lung disease, renal disease, diabetes mellitus, in-hospital life-threatening bleeding, and non-femoral access.

Conclusions

This systematic review identifies the most-common predictors for 30-day and 1-year readmission post-TAVI, including comorbidities and potentially modifiable procedural approaches and complications. These predictors can be used to identify patients at high-risk for readmission who are most likely to benefit from increased support and follow-up post-TAVI.

Managing the patient undergoing transcatheter aortic valve replacement with ongoing mitral regurgitation

INTRODUCTION

Significant mitral regurgitation (MR) frequently coexists in patients with severe symptomatic aortic stenosis undergoing transcatheter aortic valve replacement (TAVR). These patients have worse clinical outcomes than those with non-significant MR, especially if MR persists after treatment of the aortic stenosis. The optimal treatment approach for this challenging high-risk population is not well defined.

AREAS COVERED

This review aims to present the current literature on concomitant significant MR in the TAVR population, and to provide a comprehensive algorithmic approach for clinical decision-making in this challenging cohort of patients.

EXPERT OPINION

Concomitant mitral and aortic valve disease is a complex clinical entity. An exhaustive and comprehensive assessment of patient's clinical characteristics and mitral valve anatomy and function is required in order to assess the surgical risk, predict the MR response after AVR and evaluate the feasibility of percutaneous MV treatment if necessary. Further developments in transcatheter techniques will expand the indications for double valve treatment in operable and inoperable patients with concomitant significant MR and aortic stenosis.

Aortic Valve Replacement in Low-Risk Patients With Severe Aortic Stenosis Outside Randomized Trials

BACKGROUND

Recent randomized trials including low-risk patients showed positive results for transcatheter aortic valve replacement (TAVR) compared to surgical aortic valve replacement (SAVR), but patients with non-tricuspid aortic valve (NTAV), severe coronary artery disease (SevCAD), and those requiring concomitant mitral/tricuspid valve (CMTV) or concomitant ascending aorta replacement (CAAR) interventions were excluded.

OBJECTIVES

This study sought to evaluate the presence and impact of the main clinical variables not evaluated in TAVR versus SAVR trials (NTAV, SevCAD, and CMTV or CAAR intervention) in a large series of consecutive low-risk patients with severe aortic stenosis (SAS) undergoing SAVR.

METHODS

Single-center study including consecutive patients with SAS and low surgical risk (Society of Thoracic Surgeons score of <4%) undergoing SAVR. Baseline, procedural characteristics, and 30-day outcomes were prospectively collected.

RESULTS

Of 6,772 patients with SAS who underwent SAVR between 2000 and 2019, 5,310 (78.4%) exhibited a low surgical risk (mean Society of Thoracic Surgeons score: 1.94 ± 0.87%). Of these, 2,165 patients (40.8%) had at least 1 of the following: NTAV (n = 1,468, 27.6%), SevCAD (n = 307, 5.8%), CMTV (n = 306, 5.8%), and CAAR (n = 560, 10.5%). The 30-day mortality and stroke rates for the overall low-risk SAS cohort were 1.9% and 2.4%, respectively. The mortality rate was similar in the SevCAD (2.6%) and CAAR (2.1%) groups versus the rest of the cohort (odds ratio [OR]: 1.79; 95% confidence interval [CI]: 0.85 to 3.75, and OR: 1.64; 95% CI: 0.88 to 3.05, respectively), lower in the NTAV group (0.9%; OR: 0.42; 95% CI: 0.22 to 0.81), and higher in the CMTV group (5.9%; OR: 2.61; 95% CI: 1.51 to 4.5).

CONCLUSIONS

In a real-world setting, close to one-half of the low-risk patients with SAS undergoing SAVR exhibited at least 1 major criterion not evaluated in TAVR versus SAVR randomized trials. Clinical outcomes were better than or similar to those predicted by surgical scores in all groups but those patients requiring CMTV intervention. These results may help determine the impact of implementing the results of TAVR-SAVR trials in real practice and may inform future trials in specific groups.

Heart failure following transcatheter aortic valve replacement

Introduction: Over the past decade, the number of transcatheter aortic valve replacement (TAVR) procedures has increased exponentially. Despite major improvements in both device and successes, the rate of hospital readmission after TAVR remains high, with heart failure (HF) decompensation being one of the most important causes.Areas covered: This review provides an overview of the current status of HF following TAVR, including details about its incidence, clinical impact, contributing factors, and current and future treatment perspectives.Expert opinion: HF decompensation has been identified as the most common cause of rehospitalization following TAVR, and it has been associated with a negative prognosis. Multiple preexisting factors including low flow status, cardiac amyloidosis, myocardial fibrosis, multivalvular disease, pulmonary hypertension, coronary artery disease, and atrial fibrillation have been associated with an increased risk of HF events. Also, multiple post-procedural factors like the occurrence of significant paravalvular leaks, severe prosthesis-patient mismatch, and conduction disturbances have also contributed to increase this risk . Thus, reducing HF events in TAVR recipients would require a multifactorial and multidisciplinary effort including the optimization of the medical treatment and close follow-up and treatment of residual or concomitant valvular disease and conduction disturbance issues. Future studies in this challenging group of patients are warranted.

Dobutamine stress echocardiography in low-flow, low-gradient aortic stenosis with concomitant severe functional mitral regurgitation: a case report

Background 

Dobutamine stress echocardiography (DSE) in classical low-flow, low-gradient (LFLG) aortic stenosis (AS) is recommended in recent guidelines to differentiate true-severe AS from pseudo-severe AS. However, DSE for patients with concomitant significant mitral regurgitation (MR) is often inaccurate or inconclusive.

Case summary 

A 73-year-old man with a history of coronary artery bypass grafting was referred to our institution with congestive heart failure. Transthoracic echocardiogram showed severe functional MR and LFLG AS. The results of DSE to determine the severity of AS were inconclusive owing to the absence of flow reserve, usually defined as stroke volume increase of ≥20%. In addition, calcium score by computed tomography scan was also inconclusive. Our heart team decided to reassess the severity of AS after percutaneous edge-to-edge mitral valve repair (PMVR), considering the patient’s high surgical risk. Percutaneous edge-to-edge mitral valve repair was uneventful, resulting in marked reduction of MR from severe to trivial. Dobutamine stress echocardiography after PMVR revealed true-severe AS with the presence of flow reserve. Transcatheter aortic valve implantation (TAVI) was performed, and the patient ambulatorily discharged.

Discussion 

The coexistence of significant AS may lead to overestimation of the severity of MR, and reportedly, concomitant MR improves in the majority of patients after TAVI, especially MR of functional aetiology. However, the coexistence of significant MR often leads to inconclusive DSE results because dobutamine stress may worsen MR and fail to increase the stroke volume. In our case, DSE after PMVR was useful to diagnose the true-severe AS for the patient with LFLG AS and severe functional MR.