Interhospital transfer due to failed prehospital diagnosis for primary percutaneous coronary intervention: An observational study on incidence, predictors, and clinical impact

For patients with ST-elevation myocardial infarction (STEMI), guidelines recommend prehospital triage and direct referral to a percutaneous coronary intervention (PCI)-capable centre in order to minimize ischemic time. However, few have studied failed prehospital diagnosis. We assessed the incidence, predictors, and clinical impact of interhospital transfer for primary PCI after initial referral to a non-PCI-capable centre due to a failed prehospital STEMI diagnosis. We studied 846 consecutive STEMI patients undergoing primary PCI between January 2008 and January 2010. We found that 609 patients (72%) were directly admitted through prehospital triage and 127 patients (15%) required interhospital transfer after failed prehospital diagnosis. Median first medical contact to treatment time was 88 min in the prehospital diagnosis group and 155 min in the interhospital transfer group (p<0.001). In the interhospital transfer group, the first available electrocardiogram was diagnostic for STEMI in 77% of cases. Predictors of interhospital transfer were female gender, diabetes, prior myocardial infarction, and greater event location to PCI-capable centre distance. Interhospital transfer independently accounted for a 47% increase in ischemic time (95% CI 33 to 63%; p<0.001). One-year mortality was higher in the interhospital transfer group (10 vs. 5.3%; p=0.030). Despite an often-diagnostic electrocardiogram, interhospital transfer after failed prehospital diagnosis occurred in 15% of STEMI patients undergoing primary PCI. Interhospital transfer was a major predictor of ischemic time and 1-year mortality was significantly higher. Continuing efforts to optimize prehospital triage are warranted, especially among patients at higher risk of failed prehospital diagnosis.