Perioperative myocardial infarction associated with coronary artery bypass graft surgery: improved sensitivity in the diagnosis within 6 hours after operation with 99mTc-glucoheptonate myocardial imaging and myocardial-specific isoenzymes.

The present study was performed to evaluate scintigraphic imaging with technetium 99m-labeled glucoheptonate and serum enzyme levels of creatine phosphokinase isoenzyme (MB-CPK) in the early diagnosis of perioperative acute myocardial infarction associated with saphenous vein bypass graft operations. Myocardial imaging was done in 27 patients (50% of whom were considered high-risk) before operation and again 5 hours after operation. Four of these patients (15%) had both electrocardiographic and serum MB-CPK evidence of acute myocardial infarction, and all 4 had developed positive postoperative scintigrams. Four other patients had only elevated serum MB-CPK, and scintigrams became positive after operation in 3 of them. In addition, serum MB-CPK 6 hours after operation was 83 +/- 21 mIU/ml (mean +/- standard error of the mean) in patients with positive postoperative scans compared with 24 +/- 5 mIU/ml in those patients with negative postoperative scintigrams (p less than 0.001). Myocardial imaging with 99mTc-glucoheptonate in the perioperative period is rapid, safe, and atraumatic. Furthermore, our results suggest that it is a sensitive method for the early diagnosis of perioperative acute myocardial infarction, and, when imaging is combined with serum MB-CPK isoenzyme analysis, the reliability of the diagnosis of acute myocardial infarction is enhanced even further. Only 1 of the patients who showed perioperative myocardial damage had acute hemodynamic compromise or obvious impairment of recovery in the immediate postoperative period, and the 30-day mortality of the total group was 4% (1 of 27).