Pretreatment of STEMI patients with a loading-dose of unfractionated heparin (UFH) at first medical contact (FMC) vs. in the catheterization lab (cathlab) was associated with improved spontaneous reperfusion of the infarct-related artery (IRA) without increasing the risk of major bleeding, based on findings from the HELP-PCI trial presented at TCT 2024 by Jing Chen, MD, from the Renmin Hospital of Wuhan University, Wuhan, China. However, the study was not powered to answer the larger question of whether the early administration strategy reduces downstream myocardial infarction or cardiac death.

Investigators randomized 999 patients to either UFH (100 U/kg) in the cathlab (n=494) or to UFH (100 U/kg) at FMC (n=505). Baseline demographic and clinical characteristics were similar across both groups with an average age of 60 years and 18% of female. Roughly 43% of participants in both groups had a history of smoking and about 20% had diabetes.

In addition to finding that early administration of UFH at FMC improved spontaneous reperfusion of IRA, the study's results showed pretreatment also reduced 30-day risk of major adverse cardiovascular events at one year following randomization, including statistically significant reductions in readmissions for heart failure (0.8% vs. 2.0%, respectively). Researchers observed no significant difference in the rate of MACE at one year and complete myocardial reperfusion regardless of pretreatment with UFH at FMC or in the cathlab.

"Pretreatment with loading-dose UFH at FMC could be considered to reduce the inherent delay from FMC to cathlab in the current regional networks," said Chen, "thereby attenuating myocardial injury and improving clinical prognosis in patients with STEMI."

The study did have limitations, with Chen noting that "more imaging data should be obtained to elucidate coronary microvascular obstruction and dysfunction." Additionally, the TIMI flow grade – the primary endpoint – is a surrogate marker of myocardial reperfusion, and therefore might lack enough statistical power to prove the actual effect on long-term outcomes.