Validation of SYNTAX (Synergy between PCI with Taxus and Cardiac Surgery) score for prediction of outcomes after unprotected left main coronary revascularization

Objectives This study aimed to validate the SYNTAX (Synergy between PCI with Taxus and Cardiac Surgery) score representing angiographic complexity after unprotected left main coronary artery (ULMCA) revascularization. Background The validity of the SYNTAX score has been adequately evaluated. Methods The SYNTAX scores were calculated for 1,580 patients in a large multicenter registry who underwent percutaneous coronary intervention (PCI) (n = 819) or coronary artery bypass graft (CABG) (n = 761) for ULMCA stenosis. The outcomes of interests were 3-year incidences of major adverse vascular events (MAVE), including death, Q-wave myocardial infarction, and stroke and major adverse cardiac and cerebrovascular events (MACCE), including MAVE and target vessel revascularization of ULMCA. Results The incidence of 3-year MAVE was 6.2% in the lowest (≤23), 7.1% in the intermediate (23 to ∼36), and 17.4% in the highest (>36) SYNTAX score tertile groups after PCI (p = 0.010). However, the incidences of MAVE in the CABG group and MACCE in the PCI and CABG groups did not differ among the SYNTAX tertiles. In subgroups, the MAVE (p = 0.005) and MACCE (p = 0.007) rates according to the SYNTAX score tertiles were significantly different in patients receiving drugeluting stent, not in those receiving bare-metal stent. When compared with the clinical EuroSCORE (European System for Cardiac Operative Risk Evaluation), the C-indexes of SYNTAX score and Euro-SCORE were 0.59 and 0.67, respectively, for discrimination of MAVE and 0.53 and 0.57, respectively, for MACCE. Conclusions The angiographic SYNTAX score seems to play a partial role in predicting long-term adverse events after PCI for ULMCA stenosis. A complementary consideration of patient's clinical risk might improve the predictive ability of risk score.