Indexing left ventricular end‐systolic dimension to body size: Association with mortality in patients with degenerative mitral regurgitation

Aims: In patients with degenerative mitral regurgitation (DMR), left ventricular (LV) dysfunction is associated with increased risk of heart failure and excess mortality. LV end-systolic diameter (LVESD) is an established trigger for intervention, yet recommended LVESD thresholds apply poorly to patients with small body size. Whether LV normalization to body surface area (BSA) may be used as a trigger for DMR correction is unknown. We examined the link between LVESD index (LVESDi) and outcome in DMR to identify appropriate thresholds for excess mortality. Methods and results: This study focuses on 2753 consecutive patients with DMR due to flail leaflets diagnosed in tertiary centres from Europe and the United States, with prospective echocardiographic measurement of LVESD and BSA and long-term follow-up. The primary endpoint was mortality after diagnosis under conservative management. Secondary endpoints were mortality under conservative and surgical management and postoperative mortality of patients who underwent surgery. The optimal LVESDi cut-off for mortality prediction was 20 mm/m2. Irrespective of management type, 10-year survival was lower with LVESDi ≥20 mm/m2 than with LVESDi <20 mm/m2 (both p < 0.001). After covariate adjustment, LVESDi ≥20 mm/m2 was independently predictive of mortality under conservative management (adjusted hazard ratio [HR] 1.41, 95% confidence interval [CI] 1.15-1.75), and with conservative and surgical management (adjusted HR 1.34, 95% CI 1.17-1.54). LVESDi remained associated with poorer postoperative outcome in patients who underwent intervention. LVESDi showed higher incremental predictive value over the baseline model compared to LVESD. The association between LVESDi ≥20 mm/m2 and outcome was consistent in subgroups of patients with DMR. Conclusions: In severe DMR due to flail leaflets, LVESDi is a marker of risk additive and incremental to LVESD. Its use in clinical practice should lead to earlier referral to mitral valve surgery and improved long-term outcome.