Operative risk factors associated with unstable angina pectoris

We performed a prospective study in 207 patients with unstable angina pectoris (UA) to identify factors associated with operative mortality (OM) and perioperative myocardial infarction (MI) from myocardial revascularization. The OM was 3.9% (8/207) and the incidence of MI was 11% (23/207). Clinical variables (age, prior MI, electrocardiographic evidence, symptoms, left ventricular function) and operative variables (incomplete revascularization, cardiopulmonary bypass time, cross-clamp time) did not correlate with OM or MI. Operative mortality was associated with critical triple-vessel disease, but not left main coronary artery disease, and accounted for seven of the eight deaths (P less than .01). Myocardial infarction was associated with elective surgery (22/167) as opposed to urgent surgery (1/40) (P less than .01). Therefore, patients with critical triple-vessel disease are the highest risk group for OM, and urgent operation seems to reduce the incidence of MI in patients with UA.