Long-term outcomes following left main bifurcation stenting in Indian population—Analysis based on SYNTAX I and II scores

Background: Syntax 1 and recently Syntax 2 (SS2) scores are validated risk prediction models in coronary disease. Objectives: To find out the long term outcomes following stenting for unprotected left main bifurcation disease (LMD) and to validate and compare the performance of the SYNTAX scores 1 and 2 (SS1 and SS2 PCI) for predicting major adverse cardiac events (MACE) in Indian population. Methods: Single-center, retrospective, observational study involving patients who underwent percutaneous coronary intervention (PCI) with at least one stent implanted for the LMD. Discrimination and calibration models were assessed by ROC curve and the Hosmer-Lemeshow test. Results: Data of 103 patients were analyzed. The mean SS1 and SS2 scores were 27.9 and 30.7 and MACE was 16.5% at 4 years. The target lesion revascularization (TLR) rate at 4 years was 11(10.7%). There were 4 deaths (3.8%). The mean left ventricular ejection fraction (LVEF) was the only variable in SS2, which predicted cardiac events. ROC curve analysis showed both models to be accurate in predicting TLR and mortality following LM PCI. SS2 score showed a better risk prediction than SSI with AUC for TLR (SSI 0.560 and SS2PCI 0.625) and AUC for mortality (SS1 0.674 and SS2PCI 0.833). Hosmer-Lemeshow test validated the accuracy of both the risk models in predicting the events. Conclusions: Both risk models were applicable for Indian patients. The SS2 score was a better predictor for mortality and TLR. In the SS2 score, the LVEF was the most useful predictor of events after LM PCI. Keywords: Left main coronary, Bifurcation stenting, Syntax score, Outcome