Incidentally detected stenoses proximal to grafts originating below the common femoral artery: Do they affect graft patency or warrant repair in asymptomatic patients?

Objective: Stenoses in infrageniculate arteries proximal to a lower extremi ty vein graft may reduce now velocity through the bypass graft and are thou ght to predispose to graft occlusion. Repair of these lesions has been reco mmended to preserve graft function. This study was undertaken to better def ine the natural history of grafts below inflow lesions and to evaluate the necessity of repair to preserve graft patency. Methods: from 1994 through 1999, patients undergoing lower extremity vein g rafts by a single surgeon at a university hospital and an affiliated teachi ng hospital were placed in a prospective protocol for proximal infragenicul ate native artery and graft surveillance through use of duplex scanning. Th e records of those patients with grafts originating distal to the common fe moral artery were evaluated; they form the basis for this report. Arteriogr ams were obtained before bypass grafting, and no patient had a stenosis gre ater than 50% diameter reduction proximal to the graft origin. follow-up sc ans were obtained from the common femoral artery through the graft and outf low artery The peak systolic velocity and velocity ratio in an infragenicul ate native artery proximal to the graft origin were recorded, as were the l ocation and the time interval since the bypass graft. Repair of these proxi mal lesions was not performed during the course of this study. Revision of the bypass graft or its anastomoses was undertaken according to preestablis hed duplex scan criteria. Results: During this time, 288 autogenous infrainguinal bypass grafts were performed, of which 159 originated below the common femoral artery; of thes e, 74 were from the superficial femoral artery, 29 from the profunda femori s artery, 49 from the popliteal artery and 7 from a tibial artery The maxim um peak systolic velocity proximal to the graft origin was more than 250 in 38 arteries (25%) and more than 300 in 26 arteries (16%). The velocity rat io was 3.0 or more in 32 arteries at the same location as the peak systolic velocity and 3.5 or more in 23 arteries (15%), confirming hemodynamically significant stenoses at these sites. The location of peak systolic velocity was the common femoral artery in 81 patients (51%), the superficial femora l artery in 50 (31%), the popliteal artery in 22 (14%), and a tibial artery in 6 (4%). Follow-up ranged from 8 to 60 months (mean, 35 months). During follow-up, 19 patients died, 18 with patent grafts. Overall, nine grafts oc cluded. One of the occluded grafts had a velocity ratio greater than 3.0; t his may have contributed to graft thrombosis, The other occlusions resulted from an unrepaired graft lesion in 2 patients, graft infection in 2 patien ts, and graft ligation necessitated by below-knee amputation in 2 patients. No cause for the occlusion could be identified in two of the grafts (neith er had evidence of proximal arterial stenosis). Assisted primary patency ra tes were 95% and 91% at 3 and 5 years, respectively.