Mortality in type 1 vs. type 2 myocardial infarction

Abstract

Purpose: The classification of myocardial infarction (MI) into five types was introduced in 2007 as a component of the universal definition. However, no study has previously compared mortality in patients (pts) with type 1 vs. type 2 MI. Methods: During a one-year period we prospectively studied unselected pts admitted to a 1000-bed university hospital also serving as a local hospital for a catchment area of 300.000 residents. Pts having measured troponin I (cTnI) during hospitalization on clinical indication were included in the study. Pts transferred from other hospitals were excluded. The diagnosis and classification of MI were established by use of novel developed specifications and otherwise fulfilling the criteria of the universal definition. Pts were followed for at least one year, and all cause mortality was registered using the National Civil Registration Registry. Multivariate Cox PH regression analysis was performed. Results: From January 2010 to January 2011 a total of 7230 consecutive pts had cTnI measured. A total of 3762 patients qualified for inclusion, of whom 360 had a type 1 MI, and 119 pts had a type 2 MI. During a median follow-up of 2.1 years 150 pts died (31%). Mortality in type 2 MI pts was significantly higher than in type 1 MI pts: 49% vs. 26% (p<0.001). Indeed, already at one-month significant differences in mortality rates were found: 24% vs. 9% (figure). In multivariate Cox PH regression analysis the hazard ratio for type 2 MI when compared with type 1 MI was 1.9 (95% CI 1.3-2.9). ![Figure][1] Mortality in type 1 vs. type 2 MI Conclusion: The long-term mortality in type 2 MI pts is nearly twofold the mortality observed in pts with type 1 MI. The difference in mortality occurs already within the first month after the acute MI. [1]: pending:yes