STUDY PHASES The study originally was funded for a one year pilot phase. The purpose of this phase was to determine the feasibility of randomizing one patient per hospital per month. In order for the study to enter the main phase, five pilot hospitals, ranging in number of vascular surgery cases from low to high, had to achieve at least 90% of patient accrual expectations (54 out of an expected 60 patients randomized in one year). After successful completion of the pilot phase, the main study was approved. During the main phase, 18 participating hospitals will accrue patients for four years and continue postvascular surgery follow-up for one year.