Hemodynamic studies before and after extended bypass grafts to the tibial and personeal arteries.

Thirty-ones limbs of 29 consecutive patients undergoing bypass grafts to the tibial or peroneal arteries were studied. Twenty-five limbs had ischemic rest pain with or without localized gangrene, and six had incapacitating claudication. The mean segmental pressure indices were upper thigh, 1.16 +/- 0.36; above knee, 0.71 +/- 0.30; below knee 0.51 +/- 0.23; and ankle, 0.28 +/- 0.21. Indices at the ankle were significantly lower (P less than 0.005) than those obtained from limbs that were candidates for simple femoropopliteal bypass. Three grafts failed immediately (initial patency rate of 90%). In the surviving grafts, ankle pressures rose from 39 +/- 26 to 145 +/- 29 mm Hg, and the ankle pressure index increased from 0.27 +/- 0.20 to 1.03 +/- 0.15 mm Hg. Consistent with these hemodynamic changes, all patients but one initially were relieved of their symptoms, and all ischemic lesions were treated successfully. Thirteen grafts failed subsequently (21 days to 34 months). Compared with preoperative values, ankle pressures after failure were either increased or unchanged in 75% of these limbs. Early occlusion could not be predicted on the basis of a low preoperative pressure index. During follow-up, impending graft failure was detected by a fall in ankle pressure in three patients and successfully prevented.