Long-term outcome and prognostic value of angiographic slow/no-reflow phenomenon after emergency percutaneous coronary intervention for ST-elevation myocardial infarction

Background The coronary slow flow/no-reflow phenomenon (CSF/NRP) is a common complication of emergency percutaneous coronary intervention (PCI) for ST-elevated myocardial infarction (STEMI). Its long-term prognostic value, however, remains unclear. This study investigated the long-term outcome and prognostic value of CSF/NRP after emergency PCI for STEMI. Methods This retrospective, multicenter registry-based cohort study was conducted in STEMI patients who underwent emergency PCI between 2015 and 2016. Incidence of in-hospital mortality, major adverse cardiac and cerebrovascular events (MACCEs), and all-cause mortality during long-term follow-up were compared between CSF/NRP patients and the normal flow group. Cox proportional-hazards regression model was performed to identify the predictive impact of CSF/NRP in short- and long-term outcomes. Results A total of 649 STEMI patients were included in the study, of whom 193 (29.7%) developed CSF/NRP following emergency PCI. The CSF/NRP group had a higher incidence of in-hospital mortality than the non-CSF/NRP group (8.2 vs. 4.3%, P = 0.04). All-cause mortality incidence was also higher in the CSF/NRP group during 5-year follow-up (22.2 vs. 16.2%, P = 0.04). The Cox proportional hazards model adjusting for demographic and clinical variables identified the NRP as an independent predictor of 5-year cardiac mortality [hazard ratio: 1.89; 95% confidence interval (CI): 1.07–3.31; P = 0.02]. In a landmark analysis, no difference was seen in overall mortality among the two study groups between 1 month and 5-year follow-up (hazard ratio: 1.33; 95% CI: 0.80–2.21, P-value: 0.23). Kaplan–Meier analysis showed lower 3-year cumulative MACCE-free survival in the CSF/NRP group compared with the normal flow group (P = 0.02). Conclusion CSF/NRP in STEMI patients is associated with a worse short- and long-term prognosis. These results, however, are mostly related to the acute phase, and CSF/NRP had limited influence on clinical outcomes in early survivors of STEMI.