Outcomes After Transcatheter Edge-to-Edge Mitral Valve Repair According to Mitral Regurgitation Etiology and Cardiac Remodeling

The Natural History of Atrial Functional Mitral Regurgitation

BACKGROUND

The natural history of moderate/severe atrial functional mitral regurgitation (AFMR) is unknown.

OBJECTIVES

The authors sought to study the incidence of left ventricular (LV) systolic dysfunction (LVSD), progression or regression of ≥mild-moderate AFMR, and impact on mortality.

METHODS

Adults with left atrial (LA) volume index ≥40 mL/m2, ≥mild-moderate AFMR, and follow-up echocardiogram were followed for incident LVSD (ejection fraction <50% and ≥10% lower than baseline), progression of mild-moderate/moderate AFMR to severe, and persistent regression of AFMR to no/trivial. Relation of AFMR progression or regression as time-dependent covariates with all-cause mortality was studied. Incidence of LVSD was compared with patients with no/mild AFMR matched on age, sex, comorbidities and ejection fraction. Patients were followed until mitral intervention, myocardial infarction, or last follow-up.

RESULTS

A total of 635 patients (median age 75 years, 51% female, 96% mild-moderate/moderate AFMR, 4% severe AFMR) were included. Over a median 2.2 years (Q1-Q3: 1.0-4.3 years), incidence rates per 100 person-years were 3.2 for LVSD (P = 0.52 vs patients with no/mild AFMR), 1.9 for progression of AFMR, and 3.9 for regression. Female sex and larger LA volume index were independently associated with progression, whereas younger age, male sex, absent atrial fibrillation, and higher LA emptying fraction were independently associated with regression. Neither AFMR progression nor regression was independently associated with mortality. Instead, independent risk factors for mortality included older age, concentric LV geometry, and higher estimated LV filling and pulmonary pressures.

CONCLUSIONS

In patients with predominantly mild-moderate/moderate AFMR, regression of MR was more common than progression, but neither was associated with mortality. Instead, diastolic function abnormalities were more important. Over a median 2-year follow-up, LVSD risk was not increased.

Functional Mitral Regurgitation and Heart Failure With Preserved Ejection Fraction: Clinical Implications and Management

Heart failure with preserved ejection fraction (HFpEF) is highly prevalent and associated with worse cardiovascular outcomes. The pathophysiology of HFpEF mostly relies on the development of elevated left ventricle filling pressure, diastolic dysfunction, and atrial dilatation and impairment. This dynamic process may eventually lead to the development of functional mitral regurgitation (MR), characterized by mitral annular dilatation and consequent leaflet remodeling, in the context of preserved left ventricular ejection fraction. These observations highlight the possible common pathophysiology of MR and HFpEF. However, less is known about the prevalence and the clinical value of MR in the context of HFpEF. This review aims to provide an overview of the association and interplay between functional MR and HFpEF, discuss the underlying mechanisms that are common to these diseases, and summarize potential targeted pharmacological treatments.

Artificial intelligence-derived risk score for mortality in secondary mitral regurgitation treated by transcatheter edge-to-edge repair: the EuroSMR risk score

BACKGROUND AND AIMS

Risk stratification for mitral valve transcatheter edge-to-edge repair (M-TEER) is paramount in the decision-making process to appropriately select patients with severe secondary mitral regurgitation (SMR). This study sought to develop and validate an artificial intelligence-derived risk score (EuroSMR score) to predict 1-year outcomes (survival or survival + clinical improvement) in patients with SMR undergoing M-TEER.

METHODS

An artificial intelligence-derived risk score was developed from the EuroSMR cohort (4172 and 428 patients treated with M-TEER in the derivation and validation cohorts, respectively). The EuroSMR score was validated and compared with established risk models.

RESULTS

The EuroSMR risk score, which is based on 18 clinical, echocardiographic, laboratory, and medication parameters, allowed for an improved discrimination of surviving and non-surviving patients (hazard ratio 4.3, 95% confidence interval 3.7-5.0; P < .001), and outperformed established risk scores in the validation cohort. Prediction for 1-year mortality (area under the curve: 0.789, 95% confidence interval 0.737-0.842) ranged from <5% to >70%, including the identification of an extreme-risk population (2.6% of the entire cohort), which had a very high probability for not surviving beyond 1 year (hazard ratio 6.5, 95% confidence interval 3.0-14; P < .001). The top 5% of patients with the highest EuroSMR risk scores showed event rates of 72.7% for mortality and 83.2% for mortality or lack of clinical improvement at 1-year follow-up.

CONCLUSIONS

The EuroSMR risk score may allow for improved prognostication in heart failure patients with severe SMR, who are considered for a M-TEER procedure. The score is expected to facilitate the shared decision-making process with heart team members and patients.

Outcomes of transcatheter edge-to-edge repair for atrial functional mitral regurgitation

BACKGROUND

The prognostic benefits of transcatheter edge-to-edge repair (TEER) remain unclear in patients with atrial functional mitral regurgitation (AFMR).

AIMS

We aimed to investigate the clinical outcomes of TEER for patients with AFMR.

METHODS

We retrospectively classified functional mitral regurgitation (FMR) patients undergoing TEER into those with AFMR or ventricular FMR (VFMR). A residual MR ≤1+ at discharge was considered optimal mitral regurgitation (MR) reduction, and an elevated mean mitral valve pressure gradient (MPG) was defined as an MPG ≥5 mmHg at discharge. The primary outcome was a composite of all-cause mortality and hospitalisation due to heart failure within one year.

RESULTS

Of 441 FMR patients, 125 patients were considered as having AFMR. Residual MR ≤1+ was associated with a lower risk of the composite outcome in both AFMR and VFMR patients, while an MPG ≥5 mmHg was associated with a higher risk of the composite outcome in patients with AFMR but not with VFMR. AFMR patients with residual MR ≤1+ and an MPG ≥5 mmHg, as well as those with residual MR >1+, had a higher incidence of the composite outcome than those with residual MR ≤1+ and an MPG <5 mmHg (50.7%, 41.8%, and 14.3%, respectively; p<0.001). This association was consistent after adjustment for clinical and echocardiographic characteristics.

CONCLUSIONS

An MR reduction to ≤1+ following TEER was associated with a lower risk of clinical outcomes in patients with AFMR, while an MPG ≥5 mmHg was related to a higher risk of clinical outcomes. Optimal MR reduction by TEER may have potential benefits on the prognosis of patients with AFMR, although the prognostic benefit may be attenuated by an elevated MPG.

Impact of Transcatheter Edge-to-Edge Mitral Valve Repair on Atrial Functional Mitral Regurgitation from the GIOTTO Registry

Atrial functional mitral regurgitation (aFMR) has a peculiar pathophysiology that may have distinctive outcomes. We investigated the impact of transcatheter edge-to-edge repair in aFMR compared with other FMR etiologies. The GIOTTO (GIse registry Of Transcatheter treatment of MR) is a multicenter, prospective study enrolling patients with symptomatic MR treated with MitraClip up to 2020. We categorized patients with FMR as aFMR, ischemic FMR (iFMR), and nonischemic ventricular FMR (niFMR). The clinical end points were defined according to the Mitral Valve Academic Research Consortium. Of 1,153 patients, 6% had aFMR, 47% iFMR, and 47% niFMR. Patients with aFMR were older, mostly women, and had a higher atrial fibrillation rate. They had better left ventricular ejection fraction and smaller left ventricular volumes, with no difference in mitral effective regurgitant orifice area. The acute device and procedural success rates were similar among the groups. At the longest available follow-up (median 478 days, interquartile range 91 to 741 days), the rate of MR ≥2+ was similar among the groups. Patients with aFMR had a lower rate of cardiovascular death and heart failure than patients with iFMR (hazard ratio [HR] 0.43, p = 0.02) and niFMR (HR 0.45, p = 0.03). The aFMR etiology remained independently associated with the composite outcome, together with postprocedural MR ≤1+ (HR 0.63, p <0.01) and peripheral arteriopathy (HR 1.82, p = 0.003). The results of this GIOTTO subanalysis suggested that aFMR is less prevalent and associated with better outcomes compared with other causes of FMR treated by transcatheter edge-to-edge repair. Postprocedural MR >1+, peripheral vasculopathy, non-aFMR were independent predictors of worse outcomes.

Outcomes of transcatheter edge-to-edge repair for atrial functional mitral regurgitation: A meta-analysis of observational studies

BACKGROUND

Transcatheter edge-to-edge repair (TEER) may have potential benefits in the treatment of atrial functional mitral regurgitation (AFMR), but robust evidence is currently lacking. We conducted a systematic review and meta-analysis to investigate the clinical outcomes of TEER for AFMR, including comparisons to ventricular functional MR (VFMR).

METHODS

MEDLINE and EMBASE were searched through January 2023 to identify studies eligible for analysis. The primary outcome was postprocedural MR severity. Postprocedural New York Heart Association (NYHA) functional class classification and all-cause mortality were also evaluated. Outcomes were stratified into short term (postprocedure to 6 months) and long term (6 months to 2 years).

RESULTS

A total of eight observational studies met the inclusion criteria, enrolling 539 AFMR and 3486 VFMR patients. Postprocedural MR grade ≤2 in the AFMR group was observed in 93.7% (454/491 patients; 95% confidence interval (CI), 91.1%-96.2%, I2  = 24.3%) and 97.1% (89/93 patients; 95% CI, 92.9%-100%, I2  = 26.4%) in short- and long-term follow-up, respectively. There was no difference in the rates of postprocedural MR grade ≤2 between AFMR and VFMR either in short-term (risk ratio [RR], 1.00 [95% CI, 0.95-1.06]; p = 0.90; I2  = 53%) or long-term follow-up (RR, 1.08 [95% CI, 0.89-1.32]; p = 0.44; I2  = 22%). Similarly, no difference was observed between AFMR and VFMR in the rates of postprocedural NYHA class ≤2 or all-cause mortality.

CONCLUSION

TEER provides similar clinical outcomes for AFMR and VFMR. A high rate of MR grade ≤2 was observed in patients at both short- and long-term follow-ups. Further prospective studies with TEER versus medical therapy and/or rhythm control for AFMR are warranted.

Arrythmia-Mediated Valvular Heart Disease

The aging population is rising at record pace worldwide. Along with it, a steep increase in the prevalence of atrial fibrillation and heart failure with preserved ejection fraction is to be expected. Similarly, both atrial functional mitral and tricuspid regurgitation (AFMR and AFTR) are increasingly observed in daily clinical practice. This article summarizes all current evidence regarding the epidemiology, prognosis, pathophysiology, and therapeutic options. Specific attention is addressed to discern AFMR and AFTR from their ventricular counterparts, given their different pathophysiology and therapeutic needs.

Impact of Mitral Regurgitation Etiology on Mitral Surgery After Transcatheter Edge-to-Edge Repair: From the CUTTING-EDGE Registry

BACKGROUND

Although >150,000 mitral TEER procedures have been performed worldwide, the impact of MR etiology on MV surgery after TEER remains unknown.

OBJECTIVES

The authors sought to compare outcomes of mitral valve (MV) surgery after failed transcatheter edge-to-edge repair (TEER) stratified by mitral regurgitation (MR) etiology.

METHODS

Data from the CUTTING-EDGE registry were retrospectively analyzed. Surgeries were stratified by MR etiology: primary (PMR) and secondary (SMR). MVARC (Mitral Valve Academic Research Consortium) outcomes at 30 days and 1 year were evaluated. Median follow-up was 9.1 months (IQR: 1.1-25.8 months) after surgery.

RESULTS

From July 2009 to July 2020, 330 patients underwent MV surgery after TEER, of which 47% had PMR and 53.0% had SMR. Mean age was 73.8 ± 10.1 years, median STS risk at initial TEER was 4.0% (IQR: 2.2%-7.3%). Compared with PMR, SMR had a higher EuroSCORE, more comorbidities, lower LVEF pre-TEER and presurgery (all P < 0.05). SMR patients had more aborted TEER (25.7% vs 16.3%; P = 0.043), more surgery for mitral stenosis after TEER (19.4% vs 9.0%; P = 0.008), and fewer MV repairs (4.0% vs 11.0%; P = 0.019). Thirty-day mortality was numerically higher in SMR (20.4% vs 12.7%; P = 0.072), with an observed-to-expected ratio of 3.6 (95% CI: 1.9-5.3) overall, 2.6 (95% CI: 1.2-4.0) in PMR, and 4.6 (95% CI: 2.6-6.6) in SMR. SMR had significantly higher 1-year mortality (38.3% vs 23.2%; P = 0.019). On Kaplan-Meier analysis, the actuarial estimates of cumulative survival were significantly lower in SMR at 1 and 3 years.

CONCLUSIONS

The risk of MV surgery after TEER is nontrivial, with higher mortality after surgery, especially in SMR patients. These findings provide valuable data for further research to improve these outcomes.

Functional Mitral and Tricuspid Regurgitation across the Whole Spectrum of Left Ventricular Ejection Fraction: Recognizing the Elephant in the Room of Heart Failure

Functional mitral regurgitation (FMR) and tricuspid regurgitation (FTR) occur due to cardiac remodeling in the presence of structurally normal valve apparatus. Two main mechanisms are involved, distinguishing an atrial functional form (when annulus dilatation is predominant) and a ventricular form (when ventricular remodeling and dysfunction predominate). Both affect the prognosis of patients with heart failure (HF) across the entire spectrum of left ventricle ejection fraction (LVEF), including preserved (HFpEF), mildly reduced (HFmrEF), or reduced (HFrEF). Currently, data on the management of functional valve regurgitation in the various HF phenotypes are limited. This review summarizes the epidemiology, pathophysiology, and treatment of FMR and FTR within the different patterns of HF, as defined by LVEF.

Atrial functional mitral regurgitation: prevalence, characteristics and outcomes from the National Echo Database of Australia

AIMS

Atrial functional mitral regurgitation (AFMR) is characterised by left atrial and consequent mitral annular dilatation causing mitral regurgitation. AFMR is likely to become more common with population ageing, alongside increases in atrial fibrillation and heart failure with preserved ejection fraction; conditions causing atrial dilatation. Here, we aim to define the prevalence and characterise the patient and survival characteristics of AFMR in the National Echocardiographic Database of Australia (NEDA).

METHODS AND RESULTS

14 004 adults with moderate or severe FMR were identified from NEDA. AFMR or ventricular FMR (VFMR) was classified by LA size, LV size and LVEF. AFMR was found in 40% (n=5562) and VFMR in 60% (n=8442). Compared with VFMR, the AFMR subgroup were significantly older (mean age 78±11 years), with a higher proportion of females and of AF. Participants were followed up for a median of 65 months (IQR 36-116 months). After adjustment for age, sex, AF, and pulmonary hypertension, the prognosis for VFMR was significantly worse than for AFMR (HR 1.57, 95% CI 1.47 to 1.68 for all-cause and 1.73, 95% CI 1.60 to 1.88, p<0.001 for both). After further adjustment for LVEF, mortality rates were similar in VFMR and AFMR patients (HR 0.93, p=NS), though advancing age and pulmonary hypertension remained independently associated with prognosis.

CONCLUSIONS

AFMR is a common cause of significant functional MR that predominantly affects elderly female patients with AF. Advancing age and pulmonary hypertension independently associated with survival in FMR. Prognosis was better in AFMR compared with VFMR; however, this difference was accounted for by LV systolic impairment and not by MR severity.

Patient Selection for Mitral Transcatheter Edge-to-Edge Repair

Mitral regurgitation (MR) is one of the most common valvular heart diseases, with many patients remaining non-suitable for surgical interventions. Transcatheter edge-to-edge repair (TEER) is a rapidly evolving procedure that allows safe and effective reduction of MR in high-risk patients. However, adequate patient selection through clinical assessment and imaging modalities remains a key factor for procedural success. In the following review, we highlight recent developments in TEER technologies that are expanding the target population and currently available imaging modalities that allow detailed evaluation of the mitral valve and surrounding structures for optimal patient selection.

Racial disparities in characteristics and outcomes of patients undergoing mitral transcatheter edge-to-edge repair

Background

There are scarce data regarding the post-mitral transcatheter edge-to-edger repair (TEER) course in different racial groups.

Objective

To assess the impact of race on outcomes following TEER for mitral regurgitation (MR).

Methods

This is a single-center, retrospective analysis of consecutive TEER procedures performed during 2013-2020. The primary outcome was the composite of all-cause mortality or heart failure (HF) hospitalizations along the first postprocedural year. Secondary outcomes included individual components of the primary outcome, New York Heart Association (NYHA) class, MR grade, and left ventricular mass index (LVMi).

Results

Out of 964 cases, 751 (77.9%), 88 (9.1%), 68 (7.1%), and 57 (5.9%) were whites, blacks, Asians, and Hispanics, respectively. At baseline, non-whites and blacks were younger and more likely be female, based in lower socioeconomic areas, not fully insured, diagnosed with functional MR, and affected by biventricular dysfunction. Intra-procedurally, more devices were implanted in blacks. At 1-year, non-whites (vs. whites) and blacks (vs. non-blacks or whites) experienced higher cumulative incidence of the primary outcome (32.9% vs. 22.5%, p = 0.002 and 38.6% vs. 23.4% or 22.5%, p = 0.002 or p = 0.001, respectively), which were accounted for by hospitalizations in the functional MR sub-cohort (n = 494). NYHA class improved less among blacks with functional MR. MR severity and LVMi equally regressed in all groups. White race (HR 0.62, 95% CI 0.39-0.99, p = 0.047) and black race (HR 2.07, 95% CI 1.28-3.35, p = 0.003) were independently associated with the primary outcome in functional MR patients only.

Conclusion

Mitral TEER patients of different racial backgrounds exhibit major differences in baseline characteristics. Among those with functional MR, non-whites and blacks also experience a less favorable 1-year clinical outcome.

Outcomes of Transcatheter Edge-to-Edge Repair in Degenerative vs. Functional Mitral Regurgitation

Current guidelines support the use of transcatheter edge-to-edge repair (TEER) for patients with both primary and secondary mitral regurgitation. We aimed to compare the prognoses of TEER in degenerative mitral regurgitation (DMR) vs. functional mitral regurgitation (FMR). A total of 208 consecutive patients who underwent TEER over a ten-year period were analyzed. Primary endpoints included rates of all-cause death and major adverse cardiac events (MACE: composite of all-cause death, hospitalizations for heart failure, mitral valve surgery, or TEER re-intervention). A total of 148 (71%) patients were identified with FMR, while 60 (29%) were identified with DMR. Patients in the FMR group were younger (77.2 ± 8.4 vs. 80.2 ± 7.2, p = 0.02), suffered more frequently from coronary artery disease (54.1% vs. 10.0%, p = 0.02), and atrial fibrillation/flutter (70.9% vs. 38.3%, p = 0.02). Rates of 1-year death (21.6% vs. 10.0%, p = 0.03) and MACE (41.2% vs. 21.7%, p = 0.02) were higher for the FMR group, as compared to the DMR group. After correcting for variables, FMR independently predicted rates of MACE (HR-1.78, 95% CI 1.23–2.48, p = 0.04) and had a non-significant effect on one-year mortality (HR-1.67, 95%CI 0.98–3.74, p = 0.07). In our experience, worse overall 1-year composite MACE outcomes were observed after TEER in patients with FMR as compared to patients with DMR.