Objective type 2 MI tied to higher mortality risk

Outcomes are significantly worse in patients diagnosed with type 2 myocardial infarction (MI) with objective evidence of myocardial ischaemia compared with those with myocardial injury and subjective type 2 MI, reports a study.

In this observational cohort study, the authors assessed 857 adult emergency department patients undergoing high-sensitivity cardiac troponin T (hs-cTnT) measurement. Those with ≥1 hs-cTnT >99th percentile were adjudicated following the Fourth Universal Definition of Myocardial Infarction.

Participants were then classified either as subjective type 2 MI when ischaemic symptoms were the lone criteria supporting type 2 MI or as objective type 2 MI when there was more than one objective clinical feature (ie, imaging, angiography, electrocardiography) of acute myocardial ischaemia. Mortality was the primary endpoint.

Of the patients, 55 (6.4 percent) were categorized as subjective type 2 MI, 36 (4.2 percent) as objective type 2 MI, and 702 (82 percent) as myocardial injury.

Mortality risk was higher among patients with objective type 2 MI during the index presentation (17 percent vs 1.7 percent; p<0.001; hazard ratio [HR], 11.1, 95 percent confidence interval [CI], 3.7‒33.4) and at 2-year follow-up (47 percent vs 31 percent; p=0.04; HR, 1.92, 95 percent CI, 1.17‒3.14) compared with those with myocardial injury.

Additionally, objective type 2 MI was associated with a higher mortality than subjective type 2 MI at index presentation (17 percent vs 2.0 percent; p=0.01) and at 1- (25 percent vs 9.1 percent; p=0.04) and 3-month (31 percent vs 13 percent; p=0.04) follow-up. No differences in mortality were observed between subjective type 2 MI and myocardial injury.

“A more rigorous type 2 MI definition that emphasizes these criteria may facilitate diagnosis and risk-stratification,” the authors said.