In Reply:-We agree with Dr. Rigg et al. that large multicenter randomized trials are required to address most clinical outcome questions and that selection of “high-risk” patients will improve the power of such studies. We choose to study our peripheral vascular surgery patients because they were considered to be “high risk.” In our study, 85% of the patients were diabetic, 69% had hypertension, and 36% had a history of previous myocardial infarction.  In another prospective study conducted at our institution, 100 consecutive diabetic patients scheduled for vascular surgery received thallium imaging studies before surgery. Eighty percent of these patients had thallium defects, with an average of 1.8 reversible defects per patient.  We would have had to perform additional preoperative cardiac testing, such as persantine thallium or dobutamine stress echocardiography, on all enrolled patients to select an even higher risk subset, which by itself would have represented a major financial and logistical challenge.
Rigg et al. suggest that a multicenter trial with sufficient power to determine if choice of anesthesia has any influence on cardiac morbidity and mortality in peripheral vascular surgical patients is a “realistic and achievable” goal. We respectfully disagree. First, as discussed previously, it would be difficult to cost-effectively select a substantially higher risk group. Second, there are relatively few centers in the industrialized world that have the volume of high-risk peripheral vascular patients seen at our hospital. Third, if our study could be considered a pilot, it offers little encouragement to those investigators willing to undertake a larger study in hope of demonstrating any differences.
We also would like to correct a statement made by Rigg et al. They stated that postoperative epidural analgesia was not used in our study. As we previously have reported, 40% of the patients in the epidural group had epidural morphine, and there was a trend toward a higher myocardial infarction rate in that subgroup. 
Robert H. Bode, M.D., Associate Anesthetist-in-chief
Eric T. Pierce, Ph.D., M.D., Director of Clinical Research
Department of Anesthesia and Critical Care; Beth Israel Deaconess Medical Center, West Campus
One Deaconess Road; Boston, Massachusetts 02215–9985
(Accepted for publication February 3, 1997.)