Prognostic Value of the Residual SYNTAX Score on In-Hospital and Follow-Up Clinical Outcomes in ST Elevation Myocardial Infarction Patients Undergoing Percutaneous Coronary Interventions

AIMS: We investigated the prognostic significance of residual SYNTAX score (RSS) in patients undergoing PCI due to STEMI and relationship between RSS and in-hospital and long-term ischemic cardiac events. METHODS: Between June 2015 and December 2018, 538 patients who underwent primary PCI were evaluated for in-hospital events and 478 patients were evaluated for clinical events during follow-up. Primary and secondary endpoints for both in-hospital and follow-up periods were cardiac death and major adverse cardiac events (MACE). RESULTS: 538 patients were included the study. RSS values of 131 patients were 0, and RSS values of 407 patients were >0. The median value of the RSS > 0 group was 7. According to this value, the RSS > 0 group was divided into 2 groups as R-ICR (RSS < 7, N = 188) and ICR (RSS ≥ 7, n = 219). In the RSS ≥ 7 group, during in-hospital and follow-up period, both mortality and MACE rates were higher than the other two groups. Area under the curve (AUC) for RSS for in-hospital death was found to be higher than SS (p=0.035) but similar to Grace Score (GS) (p=0.651). For MACE, RSS was higher than SS (p=0.025) and higher than the GS (p=0.041). For follow-up cardiac mortality, the AUC of the RSS was found to be higher than SS (0.870/0.763, p=0.02) and GS (0.870/0.733, p=0.001). For MACE, the AUC of RSS was higher than SS (p=0.03) and GS (p=0.004). CONCLUSIONS: High RSS values in STEMI patients are associated with increased risk of ischemic cardiac events. RSS may help determine revascularization and level of additional PCI to improve prognosis by reducing the risk of ischemic cardiac events after P-PCI.