The effect of heparin administration time on thrombolysis in myocardial infarction flow grade in patients with acute ST-elevation myocardial infarction treated with primary percutaneous coronary intervention

In the clinical setting of patients with ST-elevation myocardial infarction (STEMI), there are controversies about the role of early heparin administration on the patients' outcome and the patency of the infarct-related artery (IRA). In this randomized clinical trial, we sought to investigate the effect of heparin administration time on the thrombolysis in myocardial infarction (TIMI) flow grade of patients with STEMI treated with primary percutaneous coronary intervention (PPCI).

Eligible individuals were randomly assigned to two groups: early heparin administration (90 IU/kg) in the emergency department (group A, n = 92) and late heparin administration in the Cath lab (group B, n = 77). All demographic and clinical information and on admission examinations were documented. Clinical outcomes, 40-day mortality, and left ventricular (LV) function improvement in follow-up were also collected.

The mean age of patients was 57.1 ± 8.8 and 57.5 ± 7.5 years in groups A and B, respectively (P = 0.232). The history of hypertension (HTN) (34.8% vs. 53.2%, P = 0.016) and diabetes (14.1% vs. 29.9%, P = 0.013) was significantly lower in group A. The LV ejection fraction (LVEF) changes were significant before and after the intervention within each group. However, this change was not significantly different between the groups (P = 0.592). Post-intervention complications did not differ between the two groups (P > 0.05). In the proportion of cases with TIMI flow grade less than 2 in the IRA, no significant differences were observed between the groups. [P = 0.092 for left anterior descending (LAD) and P = 0.086 for left circumflex artery (LCX)].

Although heparin administration in patients with STEMI undergoing PPCI is safe and effective, the effect appears not to be time-dependent.