Background: Degenerative mitral regurgitation (DMR) patients with resting dyspnea classified as New York Heart Association (NYHA) class IV, particularly those experiencing acute onset or rapid deterioration, pose a high-risk challenge for preprocedural planning. While surgical mitral valve repair remains the standard treatment, transcatheter mitral edge-to-edge repair (M-TEER) has emerged as a viable alternative, especially for elderly and high-risk patients. This study explores whether preprocedural NYHA class IV status influences adverse events and outcomes in DMR patients undergoing M-TEER by analyzing data from the global, multicenter PRIME-MR registry.
Methods: The PRIME-MR registry, a retrospective, investigator-initiated, multicenter initiative, comprises patients who underwent TEER for DMR across 26 high-volume centers worldwide between 2008 and 2022. The primary objective is to assess the outcomes of patients with resting dyspnea (NYHA class IV at baseline) and compare them with patients presenting with NYHA class II or III symptoms.
Results: This analysis included 2,315 patients (median age: 81 years [interquartile range (IQR) 76-85]; 45.8% female; mean STS Score [mitral repair]: 5.2% ± 4.0) with available follow-up data were included (median follow-up time 2.32 years [95%-confidence interval (CI) 2.15; 2.52]).
Among these patients, 483 (20.9%) presented with NYHA class IV symptoms at baseline. Patients with resting dyspnea demonstrated notable characteristics, including a higher degree of MR severity (MR grade IV: 89.4% compared to 79.4% in NYHA II/III, p<0.001), a more frequent history of heart failure rehospitalization in the 12 months preceding the intervention (81.7% compared to 48.6% for NYHA II/III, p<0.001), increased median LA volume (115ml compared to 107ml for NYHA II/III, p=0.002), and significantly elevated median NT-proBNP levels (3,034ng/L compared to 1,870ng/L for NYHA II/III, p<0.001). Moreover, concomitant severe tricuspid regurgitation was significantly more prevalent in NYHA class IV patients (24.5% compared to 18.4% for NYHA II/III, p=0.005).
Technical device success rates were high in both groups (NYHA IV 91.9%; NYHA II/III 92.7%, p=0.71). However, severe residual MR at discharge was significantly more frequent for NYHA IV patients (6.0% vs. 3.2% for NYHA II/III, p=0.01).
Kaplan-Meier analysis for all-cause mortality after two years revealed worse outcomes for NYHA IV patients (p log rank <0.0001; 2-year mortality rates: NYHA IV: 31.4%; NYHA II/III: 20.6%). Cox regression analysis identified NYHA class IV as significantly associated with 2-year mortality in univariate (hazard ratio [HR]=1.65; 95%-confidence interval [CI]: 1.33-2.03; p<0.001) and multivariable analysis adjusted for age, gender, atrial fibrillation and baseline MR severity (HR=1.60; 95%-CI: 1.29-2.00; p<0.001).
Conclusion: NYHA class IV symptoms at baseline is a significant predictor of poorer outcomes in patients with DMR undergoing M-TEER. Patients with NYHA class IV symptoms exhibit higher DMR severity, history of heart failure rehospitalization, and increased mortality out to two year follow-up. These findings underscore the need for enhanced monitoring and management in this high-risk subgroup.
