A quantitative analysis of the benefits of pre-hospital infarct angioplasty triage on outcome in patients undergoing primary angioplasty for acute myocardial infarction

Abstract

Primary coronary angioplasty has been shown to be a very effective reperfusion modality in patients with acute myocardial infarction (MI). However, the time from diagnosis to therapy is often very long, often due to interhospital transfer of the patient. This study evaluates the effect of improving logistics by early infarct diagnosis in the ambulance (ambulance group) and subsequent transportation to a percutaneous coronary intervention (PCI) centre without visiting a nearby non-PCI clinic (referred group). Pre-hospital infarct diagnosis and triage in the ambulance (n=209) were compared with triage at a referral non-PCI centre (n=258) in patients included in the On-TIME (Ongoing Tirofiban In Myocardial infarction Evaluation) study. Baseline characteristics of the two patient groups did not differ significantly, with the exception of a higher prevalence of males in the ambulance group. The ambulance group had a significantly shorter time to treatment (177 vs. 208 min; P<0.01), a higher initial patency rate (44 vs. 35%; P=0.045), a better extent of myocardial reperfusion (myocardial blush grade 3: 59 vs. 47%; P=0.02), a trend toward a higher prevalence of aborted MI (15 vs. 10%; P=0.08), and a significantly lower rate of death or re-MI at 1 year of follow-up (3 vs. 10%; P=0.004). It was concluded that early, pre-hospital infarct diagnosis in the ambulance with immediate transportation to the nearest PCI centre is associated with a shorter time to treatment and improved angiographic and clinical outcomes compared with referral from a non-PCI centre in patients who are candidates to undergo primary angioplasty for acute MI.