Higher syntax score is not predictive of late mortality in 'real-world' patients with multivessel coronary artery disease undergoing coronary artery bypass grafting

Background: The Syntax score (SS) is a helpful tool for determining the optimal revascularization strategy regarding coronary artery bypass surgery (CABG) vs. percutaneous coronary intervention (PCI) in patients with complex coronary disease. While an association between higher SS and mortality was found for PCI patients, no such association was found for CABG patients. Objectives: To assess whether the SS predicts late mortality in patients undergoing CABG in a real-world setting. Methods: The study included 406 consecutive patients referred for CABG over a 2 year period. Baseline and clinical characteristics were collected. Angiographic data SS were interpreted by an experienced angiographer. Patients were divided into three groups based on SS tertiles: low ≤ 21 (n=205), intermediate 22–31 (n=138), and high ≥ 32 (n=63). Five year mortality was derived from the National Mortality Database. Results: Compared with low SS, patients with intermediate and high scores were significantly older (P = 0.02), had lower left ventricular ejection fraction (64% vs. 52% and 48%, P < 0.001) and greater incidence of acute coronary syndrome, left main disease, presence of chronic total occlusion of the left anterior descending and/or right coronary artery, and a higher EuroSCORE (5% vs. 5% and 8%, P < 0.01). Patients with intermediate and high SS had higher 5 year mortality rates (18.1% and 19%, respectively) compared to patients with low score (9.8%, P = 0.04). On multivariate analysis, SS was not an independent predictor of late mortality. Conclusion: Patients with lower SS had lower mortality after CABG, which is attributable to lower baseline risk. SS is not independently predictive of late mortality in patients with multi-vessel coronary artery disease undergoing CABG.