ANESTHESIA IN PERIPHERAL VASCULAR SURGERY

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Whether regional anesthesia or general anesthesia is associated with a higher perioperative morbidity in patients with cardiovascular disease is an important clinical issue commonly debated among medical specialists. No well designed prospective studies examining this issue have been performed, and arguments currently rely on evidence which is anecdotal, subjective, or circumstantial. To determine if epidural anesthesia (as a subset of regional) and general anesthesia exhibit comparable rates of intra- and postoperative myocardial ischemia, we propose a randomized clinical trial of 200 patients undergoing lower extremity vascular graft surgery at the Johns Hopkins Hospital over a four year period. Specific aims of this study are (1) to compare rates of perioperative myocardial ischemia, infarction, and death, in patients randomized to epidural and general anesthesia; (2) to identify high-risk subgroups in whom ischemia occurs frequently, regardless of the anesthetic method; and (3) to access and characterize the relative difficulty of achieving predetermined hemodynamic goals between the two techniques. Consenting patients will answer a standardized medical history questionnaire, undergo a physical examination, and then, if qualified, be randomized to receive either epidural or general anesthesia. During surgery both the anesthetic technique and the hemodynamic management will be specified by protocol. Myocardial ischemia and infarction will be determined by evaluation of 96-hour Holter monitor recordings starting the day prior to surgery and serial, postoperative CK-MB isoenzymes and EKGs all masked as to anesthetic type. Hemodynamic instability will be determined from masked intraoperative data records as episodes of parameters beyond a specific range and as incidence of controlling interventions. Multivariate analysis will be used to develop models for the occurrence of ischemia with the specific purpose of establishing whether type of anesthesia is an independent predictor of cardiac endpoints.