Atrial coupling index by standard echocardiography in Degenerative Mitral Regurgitation: An incremental determinant of survival

Abstract

We ought to determine the prognostic role of left atrial coupling-index (LACI), as left atrial volume-index (LAVI) by Tissue-Doppler-Imaging a’ (TDI-a’), in a large cohort of DMR. All consecutive 4792 patients (61 ± 16 years, 48% women) with isolated DMR diagnosed at the Mayo Clinic between 2003-2011, comprehensively characterized, in whom LAVI and TDI-a’ in sinus rhythm was prospectively measured in routine practice, was enrolled and their long-term survival analyzed. LACI (5.8 ± 3.7-T1 < 3.8; T2 3.8–6.3; T3 > 6.3) was significantly higher through different DMR grades (no, mild, moderate, severe DMR: 3.77 ± 2.26, 5.08 ± 2.95, 6.54 ± 3.74 and 7.84 ± 4.29 respectively; P < 0.0001). Independent determinants of LA dysfunction were age, E/e’, LV-ESD, MR grade, and LV-EF (all P ≤ 0.0001). LACI > 6 was independently associated with worse clinical presentation. Total follow-up was 7 ± 3 years, during which 1146 (24%) underwent MR surgery (94% repair-6% replacement) and 880 (18%) died. Survival throughout follow-up (10-year 76 ± 1%) was strongly associated with LACI (88 ± 1% vs. 78 ± 1% and 62 ± 2% for LACI < 3.8, 3.8–6.3 and ≥ 6.3, P < 0.0001) independent of DMR severity [adjusted HR 1.20(1.04–1.39) for LACI > 5.79, P = 0.01]. Survival improved after MR surgery [0.40(0.28–0.65), P < 0.0001]. Importantly, LACI was incremental to conventional determinants of survival ( P < 0.0001) with Net-reclassification-improvement vs. LAVI of 0.21 ± 0.02, P < 0.0001 ( Fig. 1 ). LA function assessed by LACI in routine practice displays incremental and independent link to excess-mortality, partially alleviated by mitral surgery. Thus, LACI is a simple tool of crucial interest in DMR risk-stratification.