Universal Definition of Myocardial Infarction: Clinical Insights

Abstract

Aims: The universal definition of myocardial infarction (MI) classifies acute ischaemia into different classes according to lesion mechanism. Our aim was to perform a detailed comparison between these different types of MI in terms of baseline characteristics, management and prognosis. Methods and Results: An observational retrospective single-centre cohort study was performed, including 1,000 consecutive patients admitted for type 1 (76.4%) or type 2 MI (23.6%). Type 2 MI patients were older, had a higher prevalence of comorbidities and worse medical status at admission. In-hospital mortality did not differ significantly between the MI groups (8.8 vs. 9.7%, p = 0.602). However, mortality during follow-up was almost 3 times higher in type 2 MIs (HR 2.75, p < 0.001). Type 2 MI was an independent all-cause mortality risk marker, adding discriminatory power to the GRACE model. Finally, important differences in traditional risk score performances (GRACE, CRUSADE) were found between both MI types. Conclusions: Several important baseline differences were found between these MI types. Regarding prognosis, long-term survival is significantly compromised in type 2 MIs, potentially translating patients' higher medical complexity and frailty. Distinction between type 1 and type 2 MI seems to have important implications in clinical practice and likely also in the results of clinical trials.