Prognostic Implications of Right Ventricular Dysfunction in Severe 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 mortality in patients with DMR. Methods and Results We used data from the MIDA‐Q (Mitral Regurgitation International DAtabase‐Quantitative) registry, 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 2917 (mean age: 66 years, 70.8% male patients, follow‐up: 5.2 [3.3–8.3] years) consecutive patients with severe DMR was included and long‐term mortality was analyzed. RVD, identified in 426 (14.6%) patients, was associated with reduced 8‐year survival (55%±3% versus 77%±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 hazard ratio, 1.44 [95% CI, 1.17–1.77]; P <0.001). This excess mortality was observed under medical management (adjusted hazard ratio, 1.57 [95% CI, 1.20–2.05]; P =0.001) and after surgical correction of mitral regurgitation (adjusted hazard ratio, 1.45 [95% CI, 1.02–2.05]; P =0.039). Patients with RVD undergoing surgery within 3 months of diagnosis experienced a better 8‐year survival (73%±4% versus 43%±4%; P <0.001), even after adjustment (adjusted hazard ratio, 0.44 [95% CI, 0.29–0.67]; P <0.001) despite an increase of 1‐month postoperative mortality (7.1% versus 0.5% for patients without RVD; P <0.001). Conclusions RVD is observed in 14.6% of severe 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.