Unmet needs for emergency care and prevention of prehospital death in acute myocardial infarction

Introduction: Percutaneous coronary intervention (PCI) has successfully reduced the mortality of patients with acute myocardial infarction (AMI). However, patients with out-of-hospital cardiac arrest have high mortality, which is difficult to control by hospital staff. In this study, we investigated the prevalence of prehospital death (PHD) in patients with AMI. Furthermore, we investigated the risk factors associated with 30-day mortality in patients with AMI who survived PHD.Methods: We investigated the prevalence of PHD using data from the Yamagata AMI registry and from death certification of the entire Yamagata Prefecture in Japan between 2010 and 2015. Furthermore, we investigated the risk factors for 30-day mortality in patients who survived PHD, using data from the Yamagata AMI registry from 1993 to 2015. AMI was identified by the International Classification of Diseases, 10th revision code I21.Results: Out of the 6984 patients with AMI, 3771 patients had PHD. Patients with PHD were older and more likely to be women than those without PHD. More PHD occurred in winter and spring than in summer or autumn. Multivariate regression analysis showed that age, female sex, and winter onset were independently associated with PHD.We also investigated the risk factors associated with 30-day mortality in 9675 patients who survived PHD. The rate of PCI was remarkably lower in patients with acute death than in those without acute death. Multivariate regression analysis showed that age, anterior infarction, estimated glomerular filtration rate, Killip class, and PCI were independently associated with 30-day mortality after adjusting for confounding factors.Conclusion: Approximately half of the patients with AMI died before they could reach the destination hospital. Although emergency PCI is the most important factor in reducing 30-day mortality in patients with AMI, attempts to reduce patient delay and system delay are possibly needed to further reduce PHD.