Prognostic Implications of Right Ventricular Dysfunction in Degenerative Mitral Regurgitation

Background: The prevalence and impact of right ventricular dysfunction (RVD) in degenerative mitral regurgitation (DMR) is unknown. We aimed to determine whether RVD assessed by echocardiography in routine clinical practice is independently associated with survival in patients with DMR. Methods: We used data from the Mitral Regurgitation International DAtabase-Quantitative (MIDA-Q) which included patients with isolated DMR due to mitral valve prolapse from January 2003 to January 2020 from 5 tertiary centers across North America, Europe, and the Middle East. A cohort of 4,379 (mean age: 67 years, 64.6% males, follow-up:5.3[3.3-8.2]years) consecutive patients with significant (?moderate) DMR was included and long-term survival was analyzed. Results: RVD, identified in 584(13.3%) patients, was associated with reduced 10-year survival (49±3% vs. 67±1%, p<0.001), overall and in all subgroups of patients, even after comprehensive adjustment including left ventricular dilatation and dysfunction, DMR severity, pulmonary pressures and surgery (adjusted HR[95%CI]=1.55[1.31-1.84]; p<0.001). This excess mortality was observed under medical management (adjusted HR[95%CI]=1.39[1.12-1.72]; p=0.003) and after surgical correction of mitral regurgitation (adjusted HR[95%CI]=1.56[1.08-2.27]; p=0.019). Patients with RVD undergoing surgery within 3 months of diagnosis experienced a better 10-year survival (73±4% vs. 38±4%, p<0.001), even after adjustment (adjusted HR[95%CI]=0.53[0.35-0.81]; p=0.003) despite an increase of 1-month post-operative mortality (5% vs 2.2% for patients without RVD; p<0.001). Conclusions: RVD is observed in 13.3% of significant DMR and exhibits a powerful and independent association with excess mortality partially attenuated by mitral surgery. Therefore, assessment of right ventricular systolic function should be included in routine DMR evaluation and in the clinical decision-making process.