Three-dimensional mitral valve structure in predicting moderate ischemic mitral regurgitation improvement after coronary artery bypass grafting

Abstract

Objective: Focusing on 3-dimensional mitral valve structure, this study investigated predictors for moderate ischemic mitral regurgitation (IMR) improvement after off-pump coronary artery bypass grafting (OPCAB).

Methods: This study included 143 patients (age 67.6 ± 7.6 years, 32.9% female) with previous myocardial infarction and moderate IMR undergoing OPCAB. Preoperative 3-dimensional echocardiographic data were analyzed, focusing on mitral annular geometry and leaflet tethering model. Patients were grouped according to IMR at 1-year postoperative follow-up into improved (n = 65), with no or mild IMR, and failure (n = 70), with moderate or severe IMR, groups. Groups were compared to identify predictors of IMR improvement after OPCAB.

Results: Eight patients died within 1 year. At 1 postoperative year, improved group included 65 patients; failure group included 70. Improved group had less preoperative annular flattening (smaller nonplanar angle) and segmental leaflet tethering (smaller A3, P1, P2, and P3 tethering angles) than failure group. Nonplanar angle (P < .001) and P3 tethering angle (P < .001) were independent predictors of moderate IMR improvement after OPCAB. Receiver operator characteristic curves defined P3 tethering angle of 28.8° (sensitivity of 78.6%, specificity of 84.6%) and nonplanar angle of 158.1° (sensitivity, 64.3% and specificity of 86.2%) as the cutoff values.

Conclusions: Preoperative moderate IMR can be improved by OPCAB in selected patients. Less annular flattening and P3 leaflet tethering may predict improvement of moderate IMR after OPCAB, suggesting that the annular nonplanar saddle shape and less leaflet tethering toward P3 segment are important for the prognosis of moderate IMR.

Keywords: annular geometry; coronary artery bypass grafting; ischemic mitral regurgitation; leaflet tethering.