Plaque characteristics in patients with ST-segment elevation myocardial infarction and early spontaneous reperfusion

Early spontaneous reperfusion (ESR) is not an uncommon phenomenon in clinical settings.The aim of this study was to detect potential mechanisms of ESR in patients with STEMI.This prospective study enrolled a total of 241 consecutive patients with STEMI undergoing optical coherence tomography (OCT) from July 2016 to August 2019. Forty-five patients (18.7%) met angiographic ESR criteria (TIMI 3 flow on the initial angiogram). Among those without ESR (TIMI 0 flow on initial angiogram), 45 patients were assigned to the control group according to propensity score matching with the ESR group.Although the baseline characteristics of the groups were comparable, non-ruptured plaque (62.2% vs 35.6%) predominated and plaque rupture (37.8% vs 64.4%) was less common in the ESR group (p=0.011). Red thrombus (44.4% vs 77.8%) was also less common in the ESR group (p=0.001). Lastly, compared to the control group, the ESR group underwent fewer emergent stent placements (68.9% vs 91.1%, p=0.008).Relief of coronary occlusion induced by a non-ruptured plaque may contribute to ESR in patients with STEMI.