Usefulness of the SYNTAX score for predicting clinical outcome after percutaneous coronary intervention of unprotected left main coronary artery disease.

BACKGROUND: The SYNTAX score (SXscore) has been proposed recently as a valuable tool to characterize the coronary vasculature prospectively with respect to the number of lesions and their functional impact, location, and complexity. However, the prognostic value of SXscores in patients undergoing percutaneous coronary intervention of the left main artery has not been validated.

METHODS AND RESULTS: We applied the SXscore in 255 consecutive patients who underwent percutaneous coronary intervention for left main disease and explored its performance with respect to their clinical outcome. Univariate and multivariate Cox proportional hazard regression analyses were performed to evaluate the relation between the SXscore and the incidence of cardiac mortality, the primary end point of the study, and major adverse cardiac events (MACE). At 1 year, the SXscore significantly predicted the risk of cardiac death (hazard ratio, 1.12/unit increase; 95% CI, 1.06 to 1.18; P<0.001) and MACE (hazard ratio, 1.59/unit increase; 95% CI, 1.02 to 2.48; P=0.043). After adjustment for potential confounders, a higher SXscore remained significantly associated with cardiac mortality (adjusted hazard ratio, 1.15; 95% CI, 1.05 to 1.26; P=0.003) and MACE (adjusted hazard ratio, 1.06; 95% CI, 1.02 to 1.10; P=0.005). C-indexes for SXscores in terms of cardiac death and MACE were 0.83 and 0.64, respectively. Using classification tree analysis, discrimination levels of 34 and 37 were identified as the optimal cutoff to distinguish between patients at low and high risk of cardiac death and MACE, respectively.

CONCLUSIONS: The SXscore is a useful tool to predict cardiac mortality and MACE in patients undergoing percutaneous revascularization of the left main coronary artery.