The optimal timing for mitral valve (MV) surgery in asymptomatic patients with primary mitral regurgitation (MR) remains controversial. Previous studies suggested a relationship between shortening of left ventricular ejection time (LVET) and increased MR severity or worsening LV function.

We aimed at evaluating the relationship between LVET and outcome in patients with moderate or severe chronic primary MR due to prolapse.

This is a bi-center observational study. The clinical, Doppler-echocardiographic, and outcome data prospectively collected in 302 patients (median age 61 [54–74] years, 34% women) with at least moderate primary MR and no symptoms were analyzed. LVET was defined as the time from aortic valve opening to aortic valve closure by pulsed-wave Doppler. Patients were retrospectively stratified by quartiles of LVET. The primary endpoint of the study was the composite of need for MV surgery during follow-up or all-cause mortality.

During a median follow-up time of 66 (25th–75th percentile: 33–95) months, 178 patients reached the primary endpoint. Patients in the lowest quartile of LVET (<260ms) were at high-risk of adverse events compared with those in the other quartiles of LVET (global P-value=0.005, Fig. 1), while the rate of events was similar for the other quartiles (P=NS for all). After adjustment for age, gender, history of atrial fibrillation, MR severity and guideline-based MR-specific class I triggers for MV surgery (LV ejection fraction<60%, LV end-systolic diameter≥40mm) in asymptomatic primary MR, LVET<260ms was associated with an increased risk of events (adjusted HR: 1.49 [95% CI: 1.03–2.16]; P=0.033). After adjustment for age, gender, Charlson comorbidity index (without age) and MV surgery as a time-dependent covariate, there was a significant association between LVET<260ms and increased all-cause mortality risk (adjusted HR; 2.56 [95% CI: 1.25–5.25]; P=0.010).

In conclusion, we observed that shorter LVET is associated with worse outcome in patients with moderate or severe primary MR due to prolapse. Accordingly, patients with LVET<260ms experienced a 50% increased risk of adverse events during follow-up after adjustment for clinical risk factors, MR severity and current recommended triggers for MV surgery, and with an incremental prognostic value. Whether shorter LVET has a direct effect on outcomes or is solely a risk marker in primary MR requires further studies.