Predictive value of combining the SYNTAX score with reactive hyperemia index in patients with acute coronary syndrome undergoing percutaneous coronary intervention

Objective To investigate the predictive value of SYNTAX (Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) score (SS) combined with reactive hyperemia index (RHI) in predicting 2-year major adverse cardiovascular events (MACE) in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). Background Both SS and RHI are good predictors of MACE; however, it is unknown whether combining SS and RHI could improve predictability of MACE in patients with ACS undergoing PCI. Methods We undertook a prospective study in 401 ACS patients that underwent PCI. The RHI-SYNTAX score (RSS) was calculated by categorizing and summing up the RHI and SS of individual patients. Patients with RHI < 1.67 are given 1 point, RHI >= 1.67 given 0 points, and those with SS <= 22 scored as 0 and SS > 22 as 1 point. Patients were classified into three groups: low RSS (group 0), moderate RSS (group 1), and high RSS (group 2). Results Among patients in the low, moderate, and high groups, the 2-year rates of MACE were 5.50, 10.66, and 23.33%, respectively (p < .0001). Total revascularization rates were 1.83, 2.54, and 8.89%, respectively (p = .015). Ischemic stroke rates were 0.00, 3.67, and 5.56%, respectively (p = .031). By multivariate analysis, the RSS was an independent predictor of 2-year MACE (hazard ratio: 2.09, 95% CI: 1.36-3.21, p = .001). Receiver-operator characteristic analysis indicated that the area under the curve significantly improved from 0.63 to 0.69, when RHI was added to SS (p < .0001). Conclusions RSS is correlated with 2-year MACE in patients presenting with ACS undergoing PCI.