Intra-operative events do not predict perioperative myocardial infarction

Full text

Perioperative myocardial infarction (PMI) is infrequent, but has high mortality rate. Therefore, a diagnostic work up to rule out PMI is usually performed when cardiac or hemodynamic events occur during major operations. We performed this prospective study to determine whether or not these intra operative events accurately predicted the development of PMI. We hypothesized that they did. We studied patients who underwent major surgical procedures and a subsequent diagnostic work up to rule out PMI while they were in the recovery room. PMI work up included physical assessment, countinuous ECG monitoring, and three 12 lead ECG and cardiac enzymes performed every 8 h. Data collection included patient demographics, diagnoses, pre-existing cardiac risk factors, type and duration of anesthesia and surgery, intra operative cardiac and hemodynamic events, results of PMI work up, incidence of PMI and patient outcome. Fifty-eight patients entered the study, 28 males and 30 females. Their mean age was 61.8 years. Preexisting cardiac conditions included angina in 5 patients, previous MI in another 5, coronary artery bypass in 5, diabetes in 31, atherosclerotic arterial disease in 26, smoking in 35 and hypertension in 42. The mean anesthesia and operative times were 332.8 and 237.9 min, respectively. Intra operative events included hypotension in 20 patients, tachycardia in 15, hemorrhage in 6, ECG changes in 3, hypertension in 8 and physician concern for PMI risk in 6. Only one of 58 patients (1.7%) developed PMI.

Conclusion

Intra operative cardiac events alone are not very specific predictors of perioperative myocardial infarction.