Cyphering the Complexity of Coronary Artery Disease Using the Syntax Score to Predict Clinical Outcome in Patients With Three-Vessel Lumen Obstruction Undergoing Percutaneous Coronary Intervention

The Syntax score (SXscore) was recently developed as a comprehensive angiographic scoring system aiming to assist in patient selection and risk stratification of patients with extensive coronary artery disease undergoing contemporary revascularization. A validation of this angiographic classification scheme is lacking. We assessed its predictive value in patients who underwent percutaneous intervention (PCI) for 3-vessel disease and explored its performance in comparison with the modified lesion classification system of the American Heart Association/American College of Cardiology. The SXscore, applied to 1,292 lesions in 306 patients who underwent PCI for 3-vessel disease in the Arterial Revascularization Therapies Study Part II, was 4 to 54.5, and after a median of 370 days (range 274 to 400) predicted the rate of major adverse cardiac and cerebrovascular events (hazard ratio 1.08/U increase, 95% confidence interval 1.05 to 1.11, p <0.0001), with patients in the highest SXscore tertile having a significantly higher event rate (27.9%) than patients in the lowest tertile (8.7%, hazard ratio 3.5, 95% confidence interval 1.7 to 7.4, p = 0.001). By multivariable analyses, SXscore independently predicted outcome with an almost fourfold adjusted increase in the risk of major adverse cardiac and cerebrovascular events in patients with high versus low values based on the discrimination level provided by classification and regression tree analysis. Compared with the modified lesion classification scheme of the American Heart Association/American College of Cardiology, SXscore showed a greater discrimination ability (c-index 0.58 ± 0.08 vs 0.67 ± 0.08, respectively, p <0.001) and a better goodness of fit with the Hosmer-Lemeshow statistic. In conclusion, the SXscore is a promising tool to risk stratify outcome in patients with extensive coronary artery disease undergoing contemporary PCI.