Determinants of postoperative left ventricle dysfunction in patients with chronic asymptomatic severe mitral regurgitation due to myxomatous degeneration

Abstract

Purpose: The evidence supporting early surgical intervention in patients with chronic asymptomatic mitral regurgitation (MR) is steadily accumulating. Although preoperative pulmonary hypertension and left ventricular (LV) enlargement are considered when deciding on surgery, the threshold above which they influence clinical outcomes remain poorly defined. Methods: One-hundred sixty eight asymptomatic patients of mean age 60.9±12.9 years underwent mitral valve repair of severe MR due to myxomatous degeneration between 2001 and 2012. Mean preoperative left atrial diameter, LV end-systolic diameter, and right ventricular systolic pressure were 48.2±7.6 mm, 34.7±7.4 mm, and 38.4±10.6 mm Hg, respectively. Preoperative LV ejection fraction was >60% in 137 (82%) and 24 (14%) had preoperative atrial fibrillation. Clinical and echocardiographic follow-up averaged 3.3 years, and extended to 9.1 years. Results: There were no perioperative deaths. Five-year survival and freedom from recurrent MR ≥2+ were 93.1±3.4% and 94.2±2.2%, respectively. A threshold preoperative right ventricular systolic pressure >45 mm Hg and (hazard ratio, HR, 3.55±1.65,p=0.007) and LV end-systolic pressure indexed to body surface area >19 mm/m2 (HR 3.63±1.99, p=0.02) were associated with postoperative LV dysfunction, defined as a LV ejection fraction <60%. Conclusion: Mitral valve repair can be performed with favorable early and late outcomes in patients with asymptomatic severe MR. The presence of preoperative pulmonary hypertension and minimal LV enlargement were associated with postoperative LV dysfunction in this otherwise healthy population. Mitral valve repair should be considered in asymptomatic patients with a preoperative right ventricular systolic pressure >45 mm Hg or an indexed LV end-systolic diameter >19mm/m2.