Surveillance after lower extremity arterial bypass.

The elements of a surveillance program after lower limb bypass grafting to enhance graft patency continue to evolve. Graft evaluation should include clinical assessment for new or changes in limb ischemia symptoms, measurement of ankle or toe systolic pressure, or both, and duplex ultrasound imaging of the bypass graft, which in the early postoperative period is predictive of the subsequent need for bypass graft revision. The natural history of moderate graft stenosis is known, and these lesions can be safely monitored using serial testing to identify progression. The testing frequency should be individualized to the patient, type of arterial bypass, and duplex scan findings. Graft surveillance should focus on the identification and repair of critical stenosis (peak systolic velocity exceeding 300 cm/s, and peak systolic velocity ratio across the stenosis exceeding 3.5) correlating with more than 70% diameter-reducing stenosis. A graft surveillance program should result in a graft failure rate of less than 3% per year.