Numerous risk scores have been designed to predict the outcome of percutaneous coronary intervention (PCI). The Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) score has been shown to predict outcome in patients with severe coronary artery disease (CAD) randomized to PCI or bypass surgery, but its utility in patients with less severe CAD is less well established.
Methods: We calculated the SYNTAX score in 482 patients with diabetes mellitus or chronic kidney disease (serum creatinine > 1.5 mg/ml) undergoing non-emergency PCI. The study endpoint was 3-year all-cause mortality or repeat revascularization.
Results: The mean age was 69 ± 11 years, 44% were women, 82% had diabetes and they had 1.82 ± 0.78 diseased vessels. The mean creatinine clearance was 67.3 ± 37.2 ml/min. The mean SYNTAX score was 11 ± 8, median of 9 (5-15), tertiles < 7, 7-12 and > 12. There was good interobserver concordance (0.784 and 0.816, p < 0.01, respectively among two pairs of observers). The 3-year estimated survival rate was 0.85 (95% confidence interval [CI] 0.82-0.88). By multivariable analysis, creatinine clearance (hazard ratio [HR] 0.82 per 10 ml/min, p < 0.001), ejection fraction (HR 0.82 per 10%, p = 0.004) and prior infarction (HR 1.7, p = 0.03) were the only predictors of death. The SYNTAX score did not predict mortality. The incidence of repeat PCI by increasing tertiles of SYNTAX score was 19.2%, 32.2% and 33.2%, respectively, p < 0.001.
Conclusion: In patients at high risk for ischemic events without severe CAD, the SYNTAX score is not associated with mortality at 3 years.