CRYOPRESERVED SAPHENOUS-VEIN ALLOGRAFTS FOR BELOW-KNEE LOWER-EXTREMITY REVASCULARIZATION

Objective Cryopreserved saphenous vein allografts have been offered as an alternative conduit for bypass in ischemic limbs. The authors exam ined the efficacy of this conduit for arterial bypass to the distal po pliteal and tibial arteries in patients in whom autogenous vein was no t available. Summary Background Data Previous experience with arterial and venous allografts has been unsatisfactory because of aneurysmal d egeneration and poor patency. Endothelial loss and host rejection have been suggested as mechanisms of graft failure. Cryopreservation by mo dern techniques with rate controlled freezing, dimethyl sulfoxide (DMS O), and other cryopreservants, has addressed these issues and rekindle d interest in vein allografts. Methods Over a period of more than 5 ye ars, 115 cryopreserved vein allografts were implanted in 87 limbs to t he distal popliteal (14) or tibial (101) arteries. The indication for surgery was rest pain in 56 procedures (49%), gangrene in 36 (31%), cl audication in 21 (18%), and replacement of aneurysmal allografts in 2. Follow-up was 1 to 61 months (mean 25 months). Results There was no s ignificant difference in patency related to site of proximal or distal anastomosis, patency of runoff vessels, use of anticoagulation, age, sex, diabetes, hypertension, smoking, indication, source of graft, or use of multiple segments. Revision was required in six grafts for aneu rysmal dilatation. Histologic examination of explanted sections of all ografts showed no immune response, and immunosuppressive drugs were no t used. Conclusions Although limb salvage has been satisfactory, long- term patency rates for cryopreserved vein allografts are poor when com pared with autogenous vein. The cost of cryopreserved allografts far e xceeds that of prosthetic grafts, for which comparable and superior re sults have been reported. Use of cryopreserved vein allografts should be reserved for situations in which adequate lengths of autogenous vei n do not exist and the risk of infection of prosthetic grafts is high.