Sprung et al. used the Vascular Surgery Registry at The Cleveland Clinic to identify patients from January 1989 through June 1997 who underwent vascular surgery and who had perioperative myocardial infarction (PMI) during the same hospital stay. Patients who underwent abdominal or thoracic aortic reconstructive surgery, carotid endarterectomy, or peripheral vascular surgery, performed with either general or neuraxial anesthesia, were included in the review. The authors analyzed associations among patient characteristics, type of anesthetic, and surgical risk factors for PMI, comparing the patients who experienced PMI with matched control patients (1:1) who did not.
Information was collected for patients regarding preoperative cardiac history, comorbid conditions, treated diabetes mellitus, history of stroke, history of preoperative angina, and presence of preoperative coronary artery disease. Also analyzed were preoperative hematocrit and creatinine concentrations, intraoperative fluid use, estimated blood loss, and preoperative presence or absence of electrocardiographic changes consistent with myocardial disease or ischemia.
During the time period studied, 107 patients experienced PMI during their hospital stay after vascular surgery. Twenty-two of these patients died. Four patients in the control group died during hospital stay; none of these died of cardiac causes. After a univariate analysis of the data, the authors found that the following factors were associated significantly with a greater risk of PMI: valvular disease, previous congestive heart failure, surgery performed on an emergency basis, general anesthesia, preoperative diagnosis of coronary artery disease, lower preoperative and postoperative hemoglobin concentrations, increased intraoperative bleeding (as determined by the amount of cell-salvaged blood), and a lower ejection fraction. The risk of cardiac death was increased by age, recent congestive heart failure, type of surgery, lower intraoperative diastolic blood pressure, and new intraoperative ST-T changes. Having undergone coronary artery bypass graft surgery even more than 12 months before vascular surgery reduced the mortality rate after PMI by 79%.