Spontaneous Coronary Reperfusion in STEMI After Pre‐Hospital Loading Dose of Triple Antithrombotic Therapy

Background To evaluate the incidence and prognosis of spontaneous coronary reperfusion in STEMI using pre‐hospital loading dose of P2Y12 inhibitors. Methods This prospective bi‐centric study included STEMI patients who referred for primary PCI from June 1, to November 1, 2022. All patients received before hospital admission loading dose of aspirin, heparin and P2Y 12 inhibitor. The primary outcome was incidence of spontaneous coronary reperfusion (TIMI 3 flow) before primary PCI. Major in‐hospital and 1‐year events were secondary outcomes. Results Within the study period, 263 patients were admitted with ongoing STEMI and 49 of them (18.6%) had spontaneous coronary reperfusion with no significant difference between loading dose of ticagrelor ( n = 226; 85.9%) or clopidogrel ( n = 27, 10.3%) and TIMI 3 flow ( n = 41; 18.1% vs. n = 7; 25.9%, p = 0.53; respectively). Peak of T‐hs troponin ( p < 0.001) and CRP ( p = 0.03) were significantly lower in the TIMI 3 group. In multivariate analysis, out‐of‐ hospital cardiac arrests were observed twice as often in the TIMI 3 group (16.33 vs. 7.01%; p = 0.044). There was no significant difference between the two groups regarding major in‐hospital ( p = 0.69) or 1‐year major events ( p = 0.20). Conclusion Spontaneous reperfusion at admission was observed in about 20% of STEMI patients who received a pre‐hospital loading dose of antithrombotic therapy including P2Y 12 inhibitors, and was associated with markers of decrease of infarct size. The significant increase of pre‐admission cardiac arrests observed in the TIMI 3 group could be specifically explored as it might be a concern regarding future pre‐hospital reperfusion therapy strategies.