The Annals of Thoracic Surgery, Vol 31, 36-44, Copyright © 1981 by The Society of Thoracic Surgeons
Predictors of perioperative myocardial infarction in coronary artery operation
HR Baur, TA Peterson, O Arnar, PG Gannon and FL Gobel
Postoperative graft patency and thirteen perioperative variables were
evaluated as potential risk factors for perioperative myocardial infarction
(MI) in 102 consecutive patients undergoing coronary artery bypass
grafting. Also, the incidence of perioperative MI and the amount of CK-MB
released in the postoperative period were compared in three groups of
patients selected according to the myocardial preservation technique
employed: (1) topical hypothermia with and (2) without aortic
cross-clamping and (3) cardioplegia. A perioperative MI as detected by
electrocardiogram, enzymes, and myocardial scintigraphy with technetium 99
developed in 15 patients. Most important predictors of perioperative MI
were found to be (1) left main and triple-vessel coronary artery disease,
(2) a left ventricular end-diastolic pressure greater than or equal to 15
mm Hg, (3) a decreased ejection fraction (p < 0.05), and (4)
cardiopulmonary bypass time > 120 minutes (p < 0.01). The incidence
of perioperative MI was 50% in patients with three or more risk factors and
7% in those with less than three risk factors (p < 0.001). Graft patency
was similar in patients with or without perioperative MI. Differing
myocardial preservation techniques did not influence CK-MB release or the
incidence of perioperative MI. Thus, the severity of ischemic heart disease
and the length of the cardiopulmonary bypass time were important predictors
of perioperative MI while graft patency and myocardial preservation
technique did not appear to be related to its incidence in this study.
