INFRAPOPLITEAL POLYTETRAFLUOROETHYLENE AND COMPOSITE BYPASS - FACTORSINFLUENCING PATENCY

Between January 1, 1979, and December 31, 1988, 149 infrapopliteal pol ytetrafluoroethylene (PTFE) bypasses were performed in 145 patients wi th chronic, critical, limb-threatening ischemia. These operations repr esented 27.9% of 534 infrapopliteal bypasses performed during the same period. There were 92 males and 53 females. Mean age was 71.8 +/- 12. 3 years. Signs and symptoms of critical ischemia were gangrene, ulcera tion, and isolated rest pain in 101 (69%), 23 (15.3%), and 25 (16.7%) cases, respectively. A composite (PTFE-saphenous vein) graft was used in 53 (35%) cases. In 96 prosthetic bypasses the distal anastomosis wa s performed using vein patch angioplasty in 65 (44%) cases and directl y in 31 (21%). The in-hospital mortality rate was 3.3%. Patency, limb salvage, and patient survival rates were plotted according to the actu arial method and the curves obtained were compared using the log-rank test. Actuarial survival rates were 68% +/- 5% and 57% +/- 7% at 3 and 5 years, respectively. Primary patency and lower limb salvage rates w ere 41% +/- 5% and 68% +/- 6% at 3 years and 35% +/- 9% and 65% +/- 10 % at 5 years, respectively. There was no statistically significant dif ference noted in primary patency rates at 3 years according to the typ e of bypass (composite or all-prosthetic: 36% vs. 44%), the type of di stal anastomosis (direct or vein patch angioplasty: 43% vs. 45%), the site of distal anastomosis (upper or lower half of the leg: 38% vs. 46 %), lateral or medial placement of the bypass (39% vs. 43%), or accord ing to whether or not it was a repeat operation (40% vs. 44%). In conc lusion, patency rates using infrapopliteal PTFE bypasses are low. Cert ain technical approaches, although they do not seem to improve patency , definitely increase the feasibility of bypass and in our opinion dec rease the risk of early failure in unfavorable anatomic settings. The limb salvage rates following infrapopliteal PTFE and composite bypass are encouraging and justify the use of routine distal revascularizatio n, even in the absence of autogenous vein graft.