This single-center RCT in 593 STEMI patients found that unfractionated heparin (70–100 IU/kg) given at first medical contact — prior to PCI-center arrival — significantly improved TIMI 2–3 flow in the infarct-related artery at initial angiography compared with standard UFH at PCI. BARC 3–5 bleeding was similar. The trial supports prehospital heparin as a simple, low-cost reperfusion strategy ahead of primary PCI.
Background: Primary PCI is the preferred reperfusion strategy in patients with ST-elevation myocardial infarction (STEMI). We investigated benefits and safety of pretreatment with unfractioned heparin (UFH) in STEMI referred to primary PCI.Methods: Our single-center, open-label, randomized controlled trial assigned STEMI with ≤6 hours of symptom duration either to 70-100 IE/kg bolus of UFH at first prehospital medical contact (FMC) plus supplemental dose before PCI adjusted to activated clothing time ≥250 seconds or to control group undergoing standard UFH at the time of PCI. Primary efficacy endpoint was TIMI 2-3 flow in infarct related artery (IRA) at initial coronary angiography. Primary safety endpoint was BARC 3-5 bleeding during the index hospital stay.Results: From March 2022 to February 2025, 298 patients were randomized to UFH pretreatment and 295 to the control group. Both groups were comparable in age, gender, risk factors, previous cardiovascular events and median delay fro
