Troponin I in the diagnosis of postoperative myocardial infarction

To the Editor: It was a pleasure to read the article by Adams et al. on the diagnosis of perioperative myocardial infarction by the measurement of troponin I (March 10 issue).¹ Clearly, creatine kinase levels can be misleading in the perioperative period, and a better marker for perioperative myocardial injury is needed. However, we have reservations about the authors' conclusion that troponin I is more specific than creatine kinase in the diagnosis of perioperative myocardial infarction. Fractionation of the creatine kinase enzyme allows calculation of the relative index, which is defined as MB creatine kinase divided by total creatine kinase.