Disproportionate Left Ventricular Enlargement in Mitral Valve Prolapse: Prevalence, Predictors, and Association With Outcomes

Background Left ventricular (LV) end‐systolic enlargement in severe degenerative mitral‐regurgitation (MR) is a class I surgical trigger. Whether it occurs disproportionately to less‐than‐severe MR due to mitral valve prolapse and is associated with mortality are unknown. We aimed to analyze prevalence and association with survival of disproportionate LV enlargement in less‐than‐severe MR. Methods A multicenter cohort international study enrolled 2848 consecutive patients (52% women, 69±16 years) with degenerative MR prospectively quantified and graded mild or moderate. Primary end point was survival under medical management. Secondary outcome was survival throughout follow‐up stratified by performance of early mitral surgery within 3 months postdiagnosis. Results Among LV remodeling parameters (abnormal end‐diastolic diameter, LV end‐systolic diameter [LVESD] absolute and indexed), LVESD ≥40 mm (present in 12.4%) was the sole independent associate of reduced survival (5‐year 70±3 versus 76±9%; P =0.009). LVESD ≥40 mm was independently linked to larger body surface area, effective regurgitant orifice, and left atrium, and to male sex and diabetes. With multivariable comprehensive adjustment, LVESD ≥40 mm (adjusted hazard ratio [aHR], 1.25 [95% CI, 1.005–1.53]; P =0.04) remained associated with excess mortality under medical management, even after adjustment for lowered ejection fraction (aHR, 1.49 [95% CI, 1.13–1.95]; P =0.004) and in all patient subsets. Among patients with moderate degenerative MR and LVESD ≥40 mm, 22% underwent mitral surgery within 3 months, which was associated with superior survival, even after comprehensive adjustment (aHR, 0.11 [95% CI, 0.005–0.51]; P =0.002). Conclusions Disproportionate LV enlargement in patients with less‐than‐severe degenerative MR is common, particularly with larger bodies, regurgitation, and overall cardiac remodeling. LVESD ≥40 mm is associated with worse survival independent of all baseline characteristics, even lowered ejection fraction, and represents a marker for risk stratification of patients who are generally not yet considered for medical or surgical/interventional treatment.