Concomitant Mitral Regurgitation in Patients With Chronic Aortic Regurgitation

Background: Etiology, mechanisms, and survival of mitral regurgitation (MR) plus hemodynamically-significant chronic aortic regurgitation (AR) are mostly unknown. Objectives: The purpose of this study was to investigate the prevalence, mechanisms, etiologies, and survival impact of coexistent ≥ moderate MR in AR patients. Methods: Consecutive patients with ≥ moderate-severe AR were retrospectively identified between 2004 and 2019. Results: Of 1,239 eligible patients (61 ± 18 years, 80% men), 1,072 (86%) had pure AR, and 167 (14%) had AR + MR (9% functional mitral regurgitation [FMR] [84% nonischemic] and 5% organic mitral regurgitation [OMR] [62% degenerative]). At baseline transthoracic echocardiogram, pure AR versus AR + OMR versus AR + FMR exhibited differences in age (59 ± 18, 62 ± 16, and 73 ± 14 years, respectively), female sex (18%, 27%, and 39%, respectively), symptoms (36%, 41%, and 64%, respectively), atrial fibrillation (5%, 17%, and 36%, respectively), left ventricular (LV) ejection fraction (59%, 58%, and 46%, respectively), LV end-systolic dimension and volume index, ≥ moderate tricuspid regurgitation (TR) (7%, 35%, and 53%, respectively), and right ventricular systolic pressure (32 ± 11, 45 ± 15, and 50 ± 14 mm Hg, respectively), all p < 0.0001. After a median follow-up of 5.2 years (interquartile range: 2.2 to 10.0 years) and adjusting for demographics, New York Heart Association functional class, aortic valve surgery, LV ejection fraction, LV end-systolic dimension and volume index, presence of FMR was independently associated with all-cause mortality (p ≤ 0.004). Compared with pure AR, AR + MR + TR exhibited the highest adjusted risk of death (2.4-fold; p < 0.0001). When compared with expected population survival, excess mortality risks of pure AR, AR + OMR, and AR + FMR were 1.25-fold, 1.76-fold, and 2.34-fold, respectively (all p ≤ 0.02). Conclusions: In hemodynamically significant AR, coexistent MR is not uncommon (approximately 14%) and mostly comprises FMR and less commonly OMR. As compared with pure AR, AR + MR + TR exhibit the largest mortality risk. Both AR + OMR and AR + FMR carry a survival penalty compared with the general population, but AR + FMR is associated with the largest excess mortality and represents an advanced stage within the AR clinical spectrum.