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 degenerative mitral regurgitation (DMR).

All consecutive 4792 patients (61±16years, 48% women) with isolated DMR diagnosed at the Mayo Clinic 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 assessed by LACI were age, E/e′, left ventricle (LV) end-systolic-diameter, mitral regurgitation (MR) grade, and LV ejection-fraction (all P≤0.0001). LACI>6 was independently associated with worse clinical presentation. Total follow-up was 7.03±3.0years, during which 1146 (24%) underwent mitral valve surgery (94% repair – 6% replacement) and 880 (18%) died. Overall 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) even adjusting comprehensively, including for DMR severity (adjusted-hazard-ratio 1.20[1.04–1.39] for LACI>5.79, P=0.01). Survival improved after mitral-surgery (time-dependent adjusted-hazard-ratio 0.40[0.28–0.65], P<0.0001). Most importantly, LACI provided incremental prognostic over LAVI and other conventional determinants of survival (P<0.0001) with Net-reclassification-improvement vs. LAVI of 0.21±0.02, P<0.0001.

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.