BACKGROUND: Total ischemic time (IT) is the time from symptom onset to percutaneous coronary intervention (PCI) in ST-Elevation Myocardial Infarction (STEMI) patients. IT is a better predictor of mortality than door to balloon time. Current national guidelines recommend IT less than 120 minutes for STEMI patients. We studied the variation in IT among STEMI directly admitted and transfer patients by mode of hospital arrival in Texas.
METHODS: National Cardiovascular Data Registry’s (NCDR®) Acute Coronary Treatment and Intervention Outcomes Network (ACTION) Registry®-GWTG™ (Get With The Guidelines) database was used to calculate IT between the years 2011 and 2015 for STEMI patients transferred from a non-PCI capable hospital to one of 34 PCI capable hospitals, and STEMI patients directly admitted to one of 46 PCI capable hospitals. We followed national guidelines for inclusion and exclusion criteria for calculating IT. IT was categorized as less than 120 minutes, 120-239 minutes, and 240 minutes or more among those who arrived either by personal vehicle or ambulance.
RESULTS: The total sample size was 5,072 and among them 1,085 were STEMI transfer patients and 3,987 were directly admitted patients. The demographics of both groups were similar with the median age around 59 -60 years, 75% men, and 80% whites. IT < 120 minutes did not show any significant reduction in mortality compared to IT > 120 minutes in our sample (OR = 0.85, 95% CI =0.57-1.26). 75% of transfer patients and 46% of directly admitted patients arrived at the first hospital by personal vehicle. Among STEMI transfer patients, IT < 120 minutes was more common among those who arrived by ambulance (20.0%) rather than those who arrived by personal vehicle (10.0%). Among transfer patients, IT was 240 minutes or more for 50.6% of those who arrived at the first hospital by personal vehicle and for 31.9% for those who arrived by ambulance. Among directly admitted STEMI patients, IT < 120 minutes was more common among those who arrived by ambulance (42.2%) rather than those who arrived by a personal vehicle (27.0%). Among directly admitted patients, IT was 240 minutes or more for 32.4% of those who arrived at the hospital by personal vehicle and for 17.8% for those who arrived by ambulance. Median IT was 188 minutes for patients arriving by personal vehicle and 134 minutes for those arriving by ambulance.
CONCLUSIONS: Patients with heart attack symptoms should arrive at hospital by ambulance rather than personal vehicle to decrease IT.