Controversy exists concerning the usefulness and accuracy of immediate postoperative ankle-arm indexes in predicting the need for distal reconstructive procedures following aortobifemoral bypass grafting. To evaluate this concept, preoperative, immediate postoperative, and late postoperative ankle-arm indexes were calculated for 20 patients (70% had combined aortoiliac and superficial femoral disease) undergoing aortobifemoral grafting during a 12-month period. Twenty-three (58%) of the 40 limbs had greater than or equal to 0.1 (m 0.43) increase in ankle-arm index immediately after operation, of which 15 (65%) had a further increase of greater than or equal to 0.1 in late postoperative ankle-arm index. Seventeen (42%) had a decrease, < 0.1 increase, or no change in ankle-arm index immediately after operations, but ten (59%) of these had an ultimate increase of greater than or equal to 0.1 in late postoperative ankle-arm index Thirty-eight (95%) of the extremities were either asymptomatic or greatly improved. These data indicate that 1) secondary distal reconstructive procedures are infrequently necessary after aortobifemoral grafting; 2) significant changes in ankle-arm indexes occur after the immediate postoperative period; 3) the majority of limbs in which the ankle-arm index decreases, is unchanged, or insignificantly increaed early postoperatively will ultimately have a significant rise in ankle-arm index late postoperatively; and 4) immediate postoperative ankle-arm index is not an accurate or reliable predictor of the need for immediate distal reconstructive procedures after aortobifemoral grafting. The authors' current approach towards this problem is to delay secondary distal reconstructive procedures, depending upon patients' symptoms and late hemodynamic results.