Postoperative lower extremity bypass surveillance: beyond ankle arm blood pressures

Surveillance is essential to the postoperative follow-up of lower extremity bypass grafts. Early, intermediate, and late thrombosis place the patient's limb at risk, so detection of problems before the graft fails is critical. Because contrast angiography is not routinely performed for surveillance, most vascular surgeons rely on history, physical examination, and noninvasive vascular studies (NVS) to assess perfusion to the lower extremity after bypass grafting. These NVS include ankle/brachial waveforms, blood pressures, and indexes before and after exercise. The purpose of this study is to report our findings with duplex color-flow ultrasonography (DCU) to examine lower extremity bypass grafts. According to our protocol, we monitor lower extremity grafts with ankle/brachial Doppler pressures, analogue waveforms, and lower extremity exercise when possible. These NVS are performed by nurses in the vascular laboratory before the patient is discharged from the hospital, at least twice during the first year, and then annually. DCU is also performed at least two times during the first year and then annually. If the study results are abnormal or if the patient has symptoms, testing is usually repeated. When abnormalities persist contrast angiography may be warranted. We have detected anatomic and hemodynamic changes in lower extremity bypasses by use of our protocol. By adding DCU to ankle/brachial blood pressures, we have identified aneurysmal dilation, diffuse atherosclerosis, focal narrowing, arteriovenous fistulas caused by unligated venous branches, retained venous valves, and disease progression proximal or distal to the graft.(ABSTRACT TRUNCATED AT 250 WORDS)