Facilitation of primary coronary angioplasty by early start of a glycoprotein 2b/3a inhibitor: results of the ongoing tirofiban in myocardial infarction evaluation (On-TIME) trial

Abstract

Aim: Although primary angioplasty is effective despite additional transportation delay, improved patency before PCI might be obtained by starting pharmacological pre-treatment before transportation.

Methods and results: From June 2001 to November 2002, 507 patients with acute myocardial infarction, who were transferred to a PCI centre, were randomised to early, pre-hospital initiation of Tirofiban (Early) or to initiation in the catheterisation laboratory (Late). The primary end-point was TIMI flow grade 3 of the infarct-related vessel (IRV) at initial angiography, as assessed by an independent core-lab. The effect of Tirofiban on each TIMI flow component, the presence of thrombus at initial angiography and pre-PCI myocardial blush grade were secondary end-points. A large proportion of patients (41%) was diagnosed and randomised in the ambulance, without intervention of a physician. In the Early group, Tirofiban was administered a median of 59 min (range 11-178 min) earlier than in the Late group. At initial angiography, TIMI 3 flow was present in 19% the Early group and in 15% in the Late group (P = 0.22). The combined incidence of TIMI 2 or 3 flow was present in 43% in the Early group and in 34% in the Late group, respectively (P = 0.04). Thrombus or a fresh occlusion was present in 60% and 73% in the Early and Late group, respectively (P = 0.002). A pre-PCI myocardial blush grades 2 or 3 was more often present in the Early group (30% vs. 22%, P = 0.04). However, no difference in TIMI 3 flow or myocardial blush grade was found between the groups, post-PCI. At one-year follow-up, the combined incidence of death or recurrent MI was not different between the groups (7.0% vs. 7.0%, P = 0.99).

Conclusion: Early initiation of Tirofiban did not improve initial TIMI 3 flow of the IRV significantly. Despite a better patency (TIMI 2 or 3 flow), a lower prevalence of thrombus or fresh occlusion and a better myocardial perfusion in the infarct-related region pre-PCI, no beneficial effect on post-PCI angiographic or clinical outcome was found, as compared to initiation of Tirofiban in the catheterisation laboratory.