Gore-Tex autogenous vein composite grafts for tibial reconstruction

Abstract

The concept of composite grafts for revascularization of the ischemic lower extremity has been reported on numerous occasions. We have utilized this technique for approximately 8 years as an alternative for those patients who do not have an adequate length of autogenous vein for bypass grafting. We have studied composites utilizing Gore-Tex and umbilical vein for the prosthetic portion with autogenous saphenous vein, cephalic vein, or endarterectomized superficial femoral artery. Subsequent evaluation has led us to discontinue the use of endarterectomized superficial femoral artery, as we believe that this is not a satisfactory autogenous component. Whenever possible, satisfactory angiograms are obtained prior to tibial bypass surgery; when this is not possible, intraoperative angiograms are utilized to demonstrate distal tibial circulation and to determine the site of distal anastomosis. Two, and sometimes three, operating teams are employed to minimize operating time, with one team constructing the prosthetic autogenous vein anastomosis on a separate table. Improved magnification, such as 2½ power magnification, is used in all cases. For the composite anastomosis and all tibial anastomoses, meticulous technique utilizing fine sutures in the form of 6-0 and 7-0 Prolene is stressed. The tibial vessels are handled in an atraumatic fashion using either vessel loops or intraluminal occluders and avoiding the use of clamps. We have stressed technique in harvesting the autogenous vein, utilizing atraumatic dissection, and irrigation of the graft with gradual distention not to exceed 100 mm Hg with a solution of heparinized autogenous whole blood containing papaverine. After harvesting, the grafts are stored in the same solution at 4° C. Following completion of the distal tibial anastomosis, angiograms are performed in each case. No effort has been made to procure sufficient length of autogenous material to cover the crossing of the joint surface, as this has not proved a significant consideration. In the postoperative period patients are given low-dose heparin, 400 U/hr intravenously. As soon as the patient is able to take medications by mouth, aspirin and dipyridamole are started. A recent study of 56 patients with infrapopliteal Gore-Tax autogenous vein composites demonstrates a significant difference between patency rates of composite grafts used for femoral to below-knee popliteal and femoral to infrapopliteal procedures. In the infrapopliteal group there is a cumulative patency rate of 30% achieved at 7 years. Further analysis shows that there is a significant difference between patients with previously failed grafts and those with virgin procedures. For example, for all below-knee and infrapopliteal procedures of composite grafts, there is a cumulative patency rate at 3 years of 61% for patients without previously failed grafts, whereas there is a patency rate of only 17% for patients with previously failed grafts. Actual palliation, which is defined as a proportion of patients alive with patent grafts and intact limbs, shows that there is a 45% palliation rate with a mean follow-up period of 16 months. It is also interesting to note that of 71 procedures with patent grafts, only 7% required amputation. On the other hand, of 57 procedures with failed grafts, only 47%, or 27 patients, needed amputation, implying that even with graft failure the ischemic process had been reversed and amputation was avoided. It is noted throughout this study and in our previous composite series that early thrombosis with the Gore-Tex autogenous vein composite graft is a significant problem. We have been aggressive in early reoperation on the thrombosed graft and believe that these patients should be heparinized fully after the thrombectomy. We have studied a group of 27 patients who underwent 30 femoral to distal tibial or peroneal bypass grafts with creation of a side-to-side arteriovenous (AV) fistula at the distal anastomotic site. Despite initial flow rates with an average of 296 ml/mm and an initial patency rate of 97%, there were only two fistulas that remained patent in intact limbs at the conclusion of the initial 8-month study period, and limb salvage was achieved in only six cases. It is our belief at present that the creation of a side-to-side distal AV fistula in infrapopliteal bypass grafts is not helpful. In summary, we believe that the use of Gore-Tex autogenous vein composite grafts is valuable in the management of the ischemic extremity. Emphasis is placed on obtaining adequate angiography either in the preoperative or operative period in order to decide on the site of the distal bypass. Special attention is paid to the technical aspects of the surgical procedure. Completion angiography is essential in all cases. Aggressive early thrombectomy is necessary to obtain adequate factual palliation over a prolonged period of time.