Higher non-cardiac mortality and lesser impact of early revascularization in patients with type 2 compared to type 1 acute myocardial infarction: results from the Tokyo CCU Network registry.

As the definition of type 2 acute myocardial infarction (AMI) is obscure, the characteristics of this disease vary among studies. The clinical significance of type 2 AMI is unclear. We surveyed the Tokyo Cardiovascular Care Unit (CCU) Network registry between 2010 and 2014. The difference in clinical characteristics and the impact of revascularization in patients with type 1 and type 2 AMI were evaluated. The cohort study included 12514 patients admitted to CCU (type 1 AMI, 12023; type 2 AMI, 491; mean age, 68 ± 15 years; 75% male). Coronary angiography was performed in 11402 patients (95%) with type 1 AMI and 427 (87%) with type 2 AMI (p < 0.001). Type 2 AMI was associated with higher in-hospital mortality (type 1 AMI, 769 (6.4%); type 2 AMI, 54 (11.0%); adjusted odds ratio (OR) 1.64; 95% confidence interval (CI) 1.12-2.41; p = 0.011) and higher non-cardiac mortality (adjusted OR 2.19; 95% CI 1.33-3.62; p = 0.002), but similar cardiac mortality rate compared to type 1 AMI (adjusted OR 1.17; 95% CI 0.71-1.91; p = 0.539). Percutaneous coronary intervention (PCI) within 24 h after the onset was associated with lower in-hospital mortality in those with type 1 AMI (OR 0.47; 95% CI 0.40-0.55; p < 0.001), but not in those with type 2 AMI (OR 1.09; 95% CI 0.62-1.94; p = 0.763). The results persisted after adjustment for multivariate logistic regression analysis and inverted probability weighting. In conclusion, patients with type 2 AMI had higher in-hospital mortality owing to higher non-cardiac death. More refined definitions focusing on the treatment of comorbidities may be required, as the treatment strategy for type 2 AMI can be different from that for type 1 AMI.