Right ventricular exercise contractile reserve and outcomes after early surgery for primary mitral regurgitation

To assess if the lack of development of right ventricular (RV) contractile reserve during exercise echocardiography (ex-echo) might be a predictor of postoperative major adverse cardiovascular events (MACEs) in patients with primary mitral regurgitation (pMR) undergoing early surgery.

Comprehensive resting and ex-echo were performed in 142 asymptomatic patients (58±21 years, 68% men, New York Heart Association functional class ≤2) with isolated severe pMR and preserved left ventricular (LV) function (LV ejection >60%, LV end-systolic diameter <45 mm) undergoing mitral valve replacement (n=20) or repair. Postoperative MACEs were defined as occurrence of atrial fibrillation, stroke, cardiac-related hospitalisation or death. RV function was evaluated at rest in every patient during ex-echo by measuring their tricuspid annular plane systolic excursion (TAPSE) value.

After median follow-up of 30 months (IQR 16-60 months), MACEs occurred in 48 (34%) patients. Using Bayesian model averaging, among all the characteristics including the type of surgery, exercise TAPSE (ex-TAPSE) emerged as the most likely predictor of prognosis (HR 0.91, 95% CI 0.86 to 0.96). Other probable predictors were exercise fractional area change (HR 0.02, 95% CI 0.00 to 0.80), male gender (HR 0.40, 95% CI 0.21 to 0.75) and RV basal diameter (HR 1.06, 95% CI 0.98 to 1.14). In the receiver operating characteristic curve analysis, an ex-TAPSE value of <26 mm (sensitivity 73% (95% CI 61 to 84) and specificity of 86% (95% CI 77% to 93%)) defined RV dysfunction. Event-free survival at 5 years was significantly lower in the patient group that exhibited no development of RV contractile reserve during exercise: 43.9% (95% CI 31.3 to 61.4) vs 75.8% (95% CI 64.8 to 88.7).

Lack of development of exercise-induced RV contractile reserve is a prognostic predictor in patients with severe pMR undergoing early mitral valve surgery.