Left atrial enlargement of degenerative mitral regurgitation: A valuable marker of outcome in routine practice?

Left atrial (LA) enlargement is frequent in degenerative mitral regurgitation (DMR), but its link to outcome remains unproven in routine clinical practice. Thus we aimed to assess whether LA-volume-index (LAVI) measured in routine clinical practice of multiple sonographers/cardiologist is associated independently with DMR survival. A cohort of all 5769 (63 ± 16 years, 47% women) consecutive patients with degenerative mitral valve disease, in whom LAVI was prospectively measured, was enrolled and their long-term survival analyzed. LAVI (43 ± 24 ml/m 2 ) was widely distributed (< 40 mL/m 2 in 3154 patients, 40–59 ml/m 2 in 1606 and ≥ 60 ml/m 2 in 1009). Overall survival throughout follow-up (10-year 66 ± 1%) was strongly associated with LAVI (79 ± 1% vs. 65 ± 2% and 54 ± 2% for LAVI < 40, 40–59 and ≥ 60 mL/m 2 , P < 0.0001) even adjusting comprehensively, including for DMR severity (adjusted-hazard-ratio 1.05[1.03–1.08] per-10 mL/m 2 , P < 0.0001). Mortality under medical management was profoundly affected by LAVI (adjusted-HR 1.07[1.04–1.10] per-10 ml/mm 2 ; 1.55[1.31–1.84] for LAVI ≥ 60 vs. < 40 mL/m 2 , both P < 0.0001) incrementally to adjusting variables ( P < 0.0001) and in all subgroups, particularly Sinus-Rhythm (adjusted-HR 1.25[1.21–1.28]) or Atrial-Fibrillation (adjusted-HR1.10 [1.06–1.13] per-10 mL/m 2 , both P < 0.0001). Thresholds of excess-mortality in spline curve analysis were approximated 40 mL/m 2 in all subgroups. Survival markedly improved after mitral surgery (time-dependent adjusted-HR 0.43[0.36–0.53], P < 0.0001) but remained modestly linked to LAVI (10-year 85 ± 3% vs. 86 ± 2% and 75 ± 3% for LAVI < 40, 40–59 and ≥ 60 ml/m 2 , P < 0.0001) ( Fig. 1 ). The frequent LA enlargement of DMR, measured by LAVI in routine practice, displays, overall and in all subsets, powerful, incremental and independent link to excess-mortality, partially alleviated by mitral surgery. Hence, LAVI measurement should be part of routine DMR evaluation and clinical-decision-making process.