Causes of Delay and Associated Mortality in Patients Transferred With ST-Segment―Elevation Myocardial Infarction

• Published in: Circulation (New York, N.Y.) N.Y.), 2011-10, Vol.124 (15), p.1636-1644
• Main Authors: MIEDEMA, Michael D, NEWELL, Marc C, DUVAL, Sue, GARBERICH, Ross F, HANDRAN, Chauncy B, LARSON, David M, MULDER, Steven, WANG, Yale L, LIPS, Daniel L, HENRY, Timothy D
• Format: Article
• Language: English
• Subjects: Aged; Angioplasty, Balloon, Coronary; Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Delivery of Health Care; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Electrocardiography; Female; Humans; Male; Medical sciences; Middle Aged; Myocardial Infarction - mortality; Myocardial Infarction - physiopathology; Myocardial Infarction - therapy; Patient Transfer; Prospective Studies; Referral and Consultation; Time Factors
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/CIRCULATIONAHA.111.033118

Regional ST-segment-elevation myocardial infarction systems are being developed to improve timely access to primary percutaneous coronary intervention (PCI). System delays may diminish the mortality benefit achieved with primary PCI in ST-segment-elevation myocardial infarction patients, but the specific reasons for and clinical impact of delays in patients transferred for PCI are unknown. This was a prospective, observational study of 2034 patients transferred for primary PCI at a single center as part of a regional ST-segment-elevation myocardial infarction system from March 2003 to December 2009. Despite long-distance transfers, 30.4% of patients (n=613) were treated in ≤ 90 minutes and 65.7% (n=1324) were treated in ≤ 120 minutes. Delays occurred most frequently at the referral hospital (64.0%, n=1298), followed by the PCI center (15.7%, n=317) and transport (12.6%, n=255). For the referral hospital, the most common reasons for delay were awaiting transport (26.4%, n=535) and emergency department delays (14.3%, n=289). Diagnostic dilemmas (median, 95.5 minutes; 25th and 75th percentiles, 72-127 minutes) and nondiagnostic initial ECGs (81 minutes; 64-110.5 minutes) led to delays of the greatest magnitude. Delays caused by cardiac arrest and/or cardiogenic shock had the highest in-hospital mortality (30.6%), in contrast with nondiagnostic initial ECGs, which, despite long treatment delays, did not affect mortality (0%). Significant variation in both the magnitude and clinical impact of delays also occurred during the transport and PCI center segments. Treatment delays occur even in efficient systems for ST-segment-elevation myocardial infarction care. The clinical impact of specific delays in interhospital transfer for PCI varies according to the cause of the delay.