Universal definition of myocardial infarction: clinical insights

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.

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.

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.