Postoperative myocardial damage in patients with coronary artery disease undergoing major non cardiac surgery

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Abstract
A prospective study was carried out in a group of 50 patients with coronary artery disease, presenting for major non-cardiac surgery, to investigate the timing and incidence of further perioperative myocardial damage. A standardised anaesthetic was used. A standard 12-lead ECG was taken immediately before surgery and at 24, 48, and 72 hr after the start of anaesthesia. Blood samples were taken immediately preoperatively and at 6, 24, 48, and 72 hr after anaesthesia for total CK and CK-MB assay. Thirty-three patients (66%) showed ECG evidence suggestive of further infarction, and of these, two (4%) died in the immediate perioperative period. The first ECG change occurred in 27/31 (87%) by 24 hr, in 3/31 (10%) by 48 hr, and 1/31 (3%) by 72 hr. Twenty-nine patients (58%) including the two deaths showed CK-MB enzyme changes. The first elevation in CK-MB was nil at 6 hr and 72 hr, with 23/27 (85%) at 24 hr, and 4/27 (15%) at 48 hr. In 22/50 (44%) ECG and enzymes were correlative. Goldman and Cooperman risk indices were calculated for each patient. The Cooperman risk index was superior to the Goldman scale in the correlation of observed with predicted myocardial morbidity. Patients with ECG changes only before surgery were just as liable to further myocardial damage as those patients with ECG changes and a documented history of a previous infarct and/or symptoms. Myocardial damage is maximal in the first 24 hr after surgery, and may not be adequately predicted by current risk indices.