Nomogram Predicts Improvement of Ischemic Mitral Regurgitation After Coronary Artery Bypass Grafting

BACKGROUND Developing a nomogram to predict improvement in moderate ischemic mitral regurgitation (IMR) after coronary artery bypass grafting (CABG) is in need. METHODS We retrospectively collected data from 112 patients with prior myocardial infarction and moderate IMR undergoing CABG between 2010 and 2018. Patients were divided into 2 groups based on IMR degree 1 year after CABG as follows: Improved Group with no or mild IMR (n = 54) and Failure Group with moderate or severe IMR (n = 58). To determine the predictors of postoperative IMR improvement, preoperative clinical and echocardiographic data were compared, and a nomogram was formulated based on all independent predictors. Discriminative ability, calibration, and clinical usefulness of the prediction model were assessed. RESULTS Independent predictors of IMR improvement after CABG constructing the nomogram included duration between infarction and operation, posterior-inferior to left ventricular volume ratio, maximum difference of the time to reach minimum systolic volume of 16 segments, P3 leaflet tethering angle, and annular nonplanar angle. The nomogram exhibited well-fitted calibration curves and excellent discriminative ability. The area under the receiver operating characteristic curve was 0.974. Patients with a score >236 demonstrated a high probability of IMR improvement (sensitivity, 90.7%; specificity, 93.1%). Patients in the Improved Group demonstrated greater actuarial survival rates than those in the Failure Group. CONCLUSIONS The nomogram combining 5 preoperative clinical and echocardiographic predictors provides an accurate preoperative estimation of moderate IMR improvement after surgery, with excellent discriminative ability. Based on this nomogram, patients with a higher score have predicted higher probabilities of IMR improvement.