Impact of transport pathways on the time from symptom onset of ST-segment elevation myocardial infarction to door of coronary intervention facility

Abstract

Background: Reducing total ischemic time is important in achieving better outcome in ST-segment elevation myocardial infarction (STEMI). Although the onset-to-door (OTD) time accounts for a large portion of the total ischemic time, factors affecting prolongation of the OTD time are not established.

Purpose: The purpose of this study was to determine the impact of transport pathways on OTD time in patients with STEMI.

Methods and subjects: We retrospectively studied 416 STEMI patients who were divided into 4 groups according to their transport pathways; Group 1 (n = 41): self-transportation to percutaneous coronary intervention (PCI) facility; Group 2 (n = 215): emergency medical service (EMS) transportation to PCI facility; Group 3 (n = 103): self-transportation to non-PCI facility; and Group 4 (n = 57): EMS transportation to non-PCI facility. OTD time was compared among the 4 groups.

Essential results: Median OTD time for all groups combined was 113 (63-228.8)min [Group 1, 145 (70-256.5); Group 2, 71 (49-108); Group 3, 260 (142-433); and Group 4, 184 (130-256)min]. OTD time for EMS users (Groups 2 and 4) was 138 min shorter than non-EMS users (Groups 1 and 3). Inter-hospital transportation (Groups 3 and 4) prolonged OTD by a median of 132 min compared with direct transportation to PCI facility (Groups 1 and 2). Older age, history of myocardial infarction, prior PCI, shock at onset, high Killip classification, and high GRACE Risk Score were significantly more frequent in EMS users.

Principal conclusions: Self-transportation without EMS and inter-hospital transportation were significant factors causing prolongation of the OTD time. Approximately 35% of STEMI patients did not use EMS and 21% of patients were transported to non-PCI facilities even though they called EMS. Awareness in the community as well as among medical professionals to reduce total ischemic time of STEMI is necessary; this involves educating the general public and EMS crews.

Keywords: Coronary artery disease; Emergency care; Fatal cardiology; Myocardial infarction; Treatment.