Long-term survival after acute myocardial infarction in the UK and South Korea

Abstract

Background: There is a lack of international research on acute myocardial infarction (AMI) comparing whole health systems, which might help improve AMI care and outcome. Purpose(s): We assessed time trends for AMI care and outcomes in the UK and South Korea. Method(s): This is an observational study utilising multi-center registries from the UK and South Korea. Patients with AMI undergoing percutaneous coronary intervention (PCI) registered in the British Cardiovascular Intervention Society (BCIS) and the Korea Acute Myocardial Infarction Registry (KAMIR) between 2005 and 2015 were divided into 2 cohorts: UK cohort (n = 66,595) and South Korea cohort (n = 41,296). The primary endpoint of the study was survival at 3.5 years after AMI. Result(s): We assessed data for 66,233 patients in the UK and 41,240 in South Korea. Symptom-to-balloon time was shorter in the BCIS with an average of 8.1 (2.9-65.9) hours compared to 10.9 (3.8-38.4) hours in the KAMIR. Meanwhile patients in the KAMIR were more likely to have multivessel PCI for multivessel disease (43.6% vs 29.5%), drug-eluting stents (84.4% vs. 52.1%) and intravascular imaging (intravascular ultrasound: 14.9% vs 3.9%, optical coherence tomography: 0.7% vs 0.3%). More patients in the KAMIR had shock as a complication post-PCI (3.5% vs. 0.2%). Accounting for all available covariates, patients in the KAMIR had a lower risk of all-cause mortality over the 3.5 years, with an estimated reduction in the risk of death of 23% (18%~28%) at 0 years of follow-up and a further 13% (7%~17%) reduction for each year of follow-up. In adjusted subgroup analysis based on sex and type of myocardial infarction (MI), mortality difference between registries was not observed in female patients with non-ST-elevation MI. Conclusion(s): Clinically important differences were found between countries in AMI care and outcomes in this first and largest registry data comparing long-term survival in the UK and South Korea. Different patterns of mortality were observed in subgroups based on sex and type of MI.