The optimal timing for administering unfractionated heparin (UFH) to patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI) has been a topic of discussion. The HELP-PCI trial investigated whether pre-treatment with UFH at first medical contact (FMC) improves outcomes compared to administration in the catheterisation laboratory (Cath Lab).¹
HELP-PCI was an investigator-initiated, multicentre, open-label, randomised controlled trial conducted across 36 clinical centres in China. The study enrolled 999 patients with STEMI who presented within 12 hours of symptom onset and were scheduled for PPCI. Participants were randomly assigned in a 1:1 ratio to receive an intravenous bolus of UFH (100 U/kg) either at FMC (n=505) or in the Cath Lab via a catheter sheath (n=494).¹
The primary endpoint was the achievement of Thrombolysis in Myocardial Infarction (TIMI) flow grade (TFG)-3 in the infarct-related artery (IRA) on diagnostic angiography before PPCI. Secondary outcomes included major adverse cardiac and cerebrovascular events (MACCE) at 12 months and complete epicardial and myocardial reperfusion post-PPCI. The primary safety endpoint was Bleeding Academic Research Consortium (BARC) type ≥2 bleeding at 30 days.¹
Patients who received UFH pre-treatment at FMC demonstrated a significantly higher frequency of TFG-3 of the IRA before PPCI compared to those treated in the Cath Lab (23.6% vs 17.6%; odds ratio, 1.44; 95% confidence interval, 1.06–1.97; P=0.02).¹
However, there were no significant differences in the secondary endpoints. The rate of MACCE at 12 months was similar between the FMC and Cath Lab groups (5.5% vs 6.7%; hazard ratio, 0.82; P=0.44). Rates of complete epicardial and myocardial reperfusion after the procedure were also comparable. In terms of safety, the incidence of BARC type ≥2 bleeding at 30 days did not differ significantly between the two groups (0.4% vs 1.2%).¹
The findings from HELP-PCI suggest that early administration of a loading dose of UFH at FMC improves spontaneous reperfusion of the IRA without increasing the risk of major bleeding. The study authors concluded, "Pre-treatment with loading-dose UFH at FMC was associated with an improvement of spontaneous reperfusion of IRA without increasing the risk of major bleeding."¹ While this improvement in initial artery patency is notable, it did not translate into a significant reduction in 12-month MACCE in this trial.
The investigators suggest that further studies are needed to determine whether the observed benefit in TIMI flow provides additional protection for long-term clinical outcomes in patients with STEMI.¹
This study was funded by the Chinese Society of Cardiology Foundation and the National Science Foundation of China.
References
1. Chen J, Xu C, Qiu L, et al. Heparin administration at first medical contact vs immediately before primary percutaneous coronary intervention: the HELP-PCI trial. Eur Heart J. 2025;46(39):3888–3901. https://doi.org/10.1093/eurheartj/ehaf481
2. Byrne RA, Rossello X, Coughlan JJ, et al. 2023 ESC Guidelines for the Management of Acute Coronary Syndromes. Eur Heart J. 2023;44:3720–826. https://doi.org/10.1093/eurheartj/ehad191
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