Objective: The objective of this study is to evaluate the incidence, predictors, and outcome of complete ST-segment resolution (STR) during transportation after pretreatment with dual or triple antiplatelet therapy in the Ongoing Tirofiban in Myocardial Infarction Evaluation (On-TIME) 2 trial.
Methods: Patients with ST-segment elevation myocardial infarction were randomized in the ambulance to pretreatment with high-dose tirofiban (HDT) or to a control pretreatment (placebo or no HDT) on top of 600-mg clopidogrel, 500-mg aspirin, and 5000-IU unfractionated heparin. Complete STR was defined as ≥70% STR on the electrocardiogram obtained before percutaneous coronary intervention (PCI) as compared with the inclusion electrocardiogram.
Results: Complete STR before PCI occurred in 16.8% (n = 188/1121) and more frequently in the HDT group (19.0% vs 14.6%, P = .05). Independent predictors for complete STR before PCI were younger age (odds ratio [OR], 0.82; 95% confidence interval [CI], 0.70-0.96, P = .01 per 10 year increase), fast diagnosis (OR, 0.97; 95% CI, 0.97-1.0, P = .004 per 15-minute increase time from symptom onset to diagnosis), longer pretreatment time (OR, 1.09; 95% CI, 1.03-1.16, P = .003 per 15-minute increase time start study medication to angiography), and randomization to HDT (OR, 1.39; 95% CI, 1.0-1.9, P = .05). Complete STR before PCI was associated with very low 30-day (0.5% vs 2.8%, P = .07) and 1-year (1.1% vs 5.0%, P = .019) mortality.
Conclusions: Dual or triple antiplatelet pretreatment in the ambulance results in complete STR before PCI in 17% of patients. Fast ST-segment elevation myocardial infarction diagnosis, prehospital initiation of pretreatment early after symptom onset, and HDT independently predicted STR before PCI. Complete STR is associated with improved clinical outcome.
Copyright © 2011 Elsevier Inc. All rights reserved.