Perioperative Myocardial Infarction in Coronary Artery Bypass Surgery

Abstract

Perioperative myocardial infarction (PMI) as diagnosed by standard electrocardiograms (appearance of persistent Q-waves of at least 0.4 sec duration) and/or autopsy, occurred in 51 (3.8%) out of 1341 consecutive patients undergoing coronary artery bypass surgery using saphenous vein grafts. Retrospective analysis of the available data revealed that preoperative factors like sex, age, history of myocardial infarction, functional class, coronary risk factors, number of vessels diseased, and ventricular function had no influence on the incidence of PMI. However, intraoperative parameters, e.g., type and duration of cardiac arrest as well as technical errors leading to graft occlusion, significantly affected the incidence of PMI. The clinical relevance of PMI is indicated by a high early mortality of 25.5% as compared to 2.3% in patients without PMI. Improvement as well as complete alleviation of angina pectoris was less frequent in patients with PMI than in patients without PMI. The decrease in the rate of PMI from more than 18% in 1970 to less than 1% in 1978/79 confirms that such incidents should not be regarded as an inevitable risk but as a complication which can largely be avoided by proper operative technique.

Perioperative Myocardial Infarction

“…This is in agreement with the data of Codd and colleagues [24], Gray and colleagues [41] and Balderman and colleagues [7]. On the other hand, Chaitman and colleagues [22], Fennell and colleagues [38], Hacker and colleagues [43] and Namay and colleagues [73], in their follow-up studies, claimed that long term survival is significantly shorter in patients who suffered PMI compared with those who did not, even when allowance is made for the higher perioperative mortality rate in the former group. In the CASS-report on 9777 patients who underwent CABG between 1974 and 1979 [84], actuarial survival, including hospital deaths, at 1, 3 and 5 years was significantly greater in patients without infarction than in patients with PMI (96%, 94% and 90% v. 78%, 74% and 69%).…”

“…As with patients admitted for non-cardiac surgery, there is much controversy in the literature regarding preoperative variables that might predispose to PMI during CABG. According to various authors [11,43,66,87,90], age and sex are not risk factors for developing PMI during revascularization. The CASS studies [39,84] indicated that age older than 65 years was associated with both a higher perioperative morbidity, including MI, and mortality, but there was no difference between the sexes in this older age group.…”

“…The technique with cold potassium cardioplegia currently used is claimed to be among those factors that have contributed most to the reduction in the frequency of PMI during CABG [56,59]. This must be seen in connection with the duration of ischaemic cardiac arrest, as an arrest time of more than 40 min increases PMI rate [42,43,90,92]. The surgical technique, number of grafts and graft flow seem to be of importance [11,42,74,90].…”

Perioperative Myocardial Infarction in Coronary Bypass Surgery

“…In follow-up angiogr ams 25 % o f the pati ents with PMI sho wed an occl uded graft whil e II % witho ut PMI suffered graft occlusion . Graft occl usion has been found to increase th e rat e of PM1 (9) . Thus, a technical mist ake leading to the occlusion of a coronary anastomosis or incomplete endarte recto my may provok e PMI, this being called "occlusion infarctio n" .…”