Cardiac troponin T, creatinine kinase MB rise higher in type 1 vs type 2 MI

The elevation in cardiac troponin T (cTnT) and creatinine kinase MB (CK-MB) are both higher in type 1 than in type 2 myocardial infarction (MI), a study has found. In addition, cTnT tends to rise out of proportion to CK-MB in type 2 MI.

“These patterns may have considerable implications for the differentiation and subsequent treatment of patients with type 1 vs type 2 MI,” the authors said.

Retrospective data on 200 patients with MI (97 with type 1; 103 with type 2) were analysed in this study. Those with ST-segment elevation MI were excluded. The authors calculated the percentage rise from trough to peak values and the ratio of the peak to the upper limit of normal (RULN) for both cTnT and CK-MB. They also calculated the ratio of peak cTnT to peak CK-MB before and after adjusting for sex, glomerular rate (GFR), and infarct size.

Type 1 MI was more likely to be larger than type 2 MI, with a significantly higher mean percentage rise for both cTnT and CK-MB as well as higher mean RULN (cTnT: 207 vs 86; p=0.02; CK-MB: 9 vs 4; p=0.002).

A trend toward a higher risk of cTnT than CK-MB in type 2 compared with type 1 MI was observed. This was shown by the ratio of peak cTnT to peak CK-MB (0.09 in type 2 vs 0.06 in type 1 MI; p=0.06). Such difference remained significant even after adjusting for sex, GFR, and infarct size (p=0.05).

“Despite differing underlying pathophysiology, type 1 and type 2 MI share many of the same diagnostic criteria and can be challenging to differentiate in clinical practice,” the authors said. “Correctly differentiating type 1 from type 2 MI is important because they are managed differently.”