Reconciling COAPT and Mitra-FR Results Based on Mitral Regurgitation Severity and Left Ventricular Size: It's Not So Simple

Mitraclip Versus Medical Therapy or Surgery in Patients With Mitral Regurgitation: Long-Term Outcomes Determined by the Reconstruction of Individual Patient Data

Although MitraClip has been studied in numerous trials, its evidence in the long term is based on a few original studies. We used an original technique of evidence synthesis to review long-term comparative trials evaluating MitraClip. We searched the PubMed database to select long-term comparative trials of MitraClip. The endpoint was all-cause mortality (minimum follow-up, one year). Included trials were analyzed using the IPDfromKM (reconstruct Individual Patient Data from published Kaplan-Meier survival curves) method to reconstruct individual patient data from Kaplan-Meier curves. Standard survival statistics were used to interpret these long-term efficacy data. The survival benefit per patient was estimated from the restricted mean survival time (RMST). Six comparative studies of MitraClip were included; 973 patients were treated with MitraClip (six arms), 717 with medical therapy (five arms), and 80 with surgical repair or replacement (one arm). In our main analysis, the outcomes observed in patients treated with MitraClip were significantly better than those of medical therapy (hazard ratio for all-cause mortality, 0.5276; 95% confidence interval, 0.4412 to 0.6309; p < 0.001); the number of patients treated with surgery was too small to make reliable comparisons. Median survival was 30.4 months for medical therapy versus not reached for the other two groups. RMST was 43.931 and 33.756 months for MitraClip and controls, respectively, yielding a gain per patient of 10.17 months (95% confidence interval, 7.47 to 12.88). In our simplified cost-effectiveness evaluation, a gain of approximately 10 months per patient compared favorably with the device cost. Our analysis provided an original interpretation of the long-term evidence available on MitraClip.

Impact of the MitraClip G4 System on Routine Practice and Outcomes in Patients With Secondary Mitral Regurgitation

BACKGROUND

The MitraClip G4 system is a new iteration of the transcatheter edge-to-edge repair system. We assessed the impact of the G4 system on routine practice and outcomes in secondary mitral regurgitation (2°MR).

METHODS AND RESULTS

Consecutive patients with 2°MR treated with either the MitraClip G2 (n=89) or G4 (n=63) system between 2018 and 2021 were included. Baseline characteristics, procedures, and outcomes were compared. Inverse probability of treatment weighting and Cox regression were used to adjust for baseline differences. Baseline characteristics were similar, except for a lower surgical risk in the G4 group (Society of Thoracic Surgeons Predicted Risk of Mortality ≥8: 38.1% vs. 56.2%; P=0.03). In the G4 group, more patients had short (≤2 mm) coaptation length (83.7% vs. 54.0%; P<0.001) and fewer clips were used (17.5% vs. 36.0%; P=0.02). Acceptable MR reduction was observed in nearly all patients, with no difference between the G4 and G2 groups (100% vs. 97.8%, respectively; P=0.51). The G4 group had fewer patients with high transmitral gradients (>5mmHg; 3.3% vs. 13.6%; P=0.03). At 1 year, there was no significant difference between groups in the composite endpoint (death or heart failure rehospitalization) after baseline adjustment (10.5% vs. 20.2%; hazard ratio 0.39; 95% confidence interval 0.11-1.32; P=0.13).

CONCLUSIONS

The G4 system achieved comparable device outcomes to the early-generation G2, despite treating more challenging 2°MR with fewer clips.

Persistence of significant secondary mitral regurgitation post-cardiac resynchronization therapy and survival: a systematic review and meta-analysis : Mitral regurgitation and mortality post-CRT

Cardiac resynchronization therapy (CRT) significantly reduces secondary mitral regurgitation (MR) in patients with severe left ventricular systolic dysfunction. However, uncertainty remains as to whether improvement in secondary MR correlates with improvement with mortality seen in CRT. We conducted a meta-analysis to determine the association of persistent unimproved significant secondary MR (defined as moderate or moderate-to-severe or severe MR) compared to improved MR (no MR or mild MR) post-CRT with all-cause mortality, cardiovascular mortality, and heart failure hospitalization. A systematic search of PubMed, EMBASE, and Cochrane Library databases till July 31, 2022 identified studies reporting clinical outcomes by post-CRT secondary MR status. In 12 prospective studies of 4954 patients (weighted mean age 66.8 years, men 77.8%), the median duration of follow-up post-CRT at which patients were re-evaluated for significant secondary MR was 6 months and showed significant relative risk reduction of 30% compared to pre-CRT. The median duration of follow-up post-CRT for ascertainment of main clinical outcomes was 38 months. The random effects pooled hazard ratio (95% confidence interval) of all-cause mortality in patients with unimproved secondary MR compared to improved secondary MR was 2.00 (1.57-2.55); p < 0.001). There was insufficient data to evaluate secondary outcomes in a meta-analysis, but limited data that examined the relationship showed significant association of unimproved secondary MR with increased cardiovascular mortality and heart failure hospitalization. The findings of this meta-analysis suggest that lack of improvement in secondary MR post-CRT is associated with significantly elevated risk of all-cause mortality and possibly cardiovascular mortality and heart failure hospitalization. Future studies may investigate approaches to address persistent secondary MR post-CRT to help improved outcome in this population.

Transcatheter Edge-to-Edge Repair in 5,000 Patients With Secondary Mitral Regurgitation: COAPT Post-Approval Study

BACKGROUND

Real-world applicability of the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation) randomized controlled trial (RCT) has been debated because of careful patient selection and the contrasting results of the MITRA-FR (Multicentre Study of Percutaneous Mitral Valve Repair MitraClip Device in Patients with Severe Secondary Mitral Regurgitation) RCT.

OBJECTIVES

The COAPT-PAS (COAPT Post-Approval Study) was initiated to assess the safety and effectiveness of the MitraClip in patients with secondary mitral regurgitation (SMR).

METHODS

COAPT-PAS is a prospective, single-arm, observational study of 5,000 consecutive patients with SMR treated with the MitraClip at 406 U.S. centers participating in the TVT (Transcatheter Valve Therapy) registry from 2019 to 2020. The 1-year outcomes from the COAPT-PAS full cohort and the COAPT-like and MITRA-FR-like subgroups who met RCT inclusion/exclusion criteria are reported.

RESULTS

Patients in the COAPT-PAS had more comorbidities, more severe HF and functional limitations, and less guideline-directed medical therapy than those in the COAPT or MITRA-FR RCTs. Patients in the COAPT-PAS full cohort and the COAPT-like (n = 991) and MITRA-FR-like (n = 917) subgroups achieved a 97.7% MitraClip implant rate, a similar and durable reduction of mitral regurgitation to ≤2+ at 1 year (90.7%, 89.7%, and 86.6%, respectively), a large improvement in quality of life at 1 year (Kansas City Cardiomyopathy Questionnaire +29 COAPT-PAS, +27 COAPT-like, and +33 MITRA-FR-like), faster procedure times, similar or lower clinical event rates compared with the RCTs' MitraClip arms, and lower clinical event rates than the RCTs' guideline-directed medical therapy only arms. One-year heart failure hospitalizations was 18.9% in COAPT-PAS, 19.7% in COAPT-like compared with 24.9% in COAPT-RCT, and 28.7% in COAPT-PAS-MITRA-FR-like compared with 47.4% in MITRA-FR-RCT.

CONCLUSIONS

This large, contemporary, real-world study reinforces the safety and effectiveness of the MitraClip System in patients with SMR, including those who met the COAPT or MITRA-FR RCT inclusion/exclusion criteria and patients excluded from the RCTs.

Disproportionate Mitral Regurgitation Determines Survival in Acute Heart Failure

Objectives: To assess the prevalence and impact of mitral regurgitation (MR) on survival in patients presenting to hospital in acute heart failure (AHF) using traditional echocardiographic assessment alongside more novel indices of proportionality.

Background: It remains unclear if the severity of MR plays a significant role in determining outcomes in AHF. There is also uncertainty as to the clinical relevance of indexing MR to left ventricular volumes. This concept of disproportionality has not been assessed in AHF.

Methods: A total of 418 consecutive patients presenting in AHF over 12 months were recruited and followed up for 2 years. MR was quantitatively assessed within 24 h of recruitment. Standard proximal isovelocity surface area (PISA) and a novel proportionality index of effective regurgitant orifice/left ventricular end-diastolic volume (ERO/LVEDV) >0.14 mm²/ml were used to identify severe and disproportionate MR.

Results: Every patient had MR. About 331/418 (78.9%) patients were quantifiable by PISA. About 165/418 (39.5%) patients displayed significant MR. A larger cohort displayed disproportionate MR defined by either a proportionality index using ERO/LVEDV > 0.14 mm²/ml or regurgitant volumes/LVEDV > 0.2 [217/331 (65.6%) and 222/345 (64.3%), respectively]. The LVEDV was enlarged in significant MR−129.5 ± 58.95 vs. 100.0 ± 49.91 ml in mild, [p < 0.0001], but remained within the normal range. Significant MR was associated with a greater mortality at 2 years {44.2 vs. 34.8% in mild MR [hazard ratio (HR) 1.39; 95% CI: 1.01–1.92, p = 0.04]}, which persisted with adjustment for comorbid conditions (HR; 1.43; 95% CI: 1.04–1.97, p = 0.03). Disproportionate MR defined by ERO/LVEDV >0.14 mm²/ml was also associated with worse outcome [42.4 vs. 28.3% (HR 1.62; 95% CI 1.12–2.34, p = 0.01)].

Conclusions: MR was a universal feature in AHF and determines outcome in significant cases. Furthermore, disproportionate MR, defined either by effective regurgitant orifice (ERO) or volumetrically, is associated with a worse prognosis despite the absence of adverse left ventricular (LV) remodeling. These findings outline the importance of adjusting acute volume overload to LV volumes and call for a review of the current standards of MR assessment.

Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT02728739, identifier NCT02728739.