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Factors affecting the patency of infrainguinal bypass
R B Rutherford1, D N Jones, S E Bergentz
1University of Colorado Health Services Center, Denver.
Insights
For difficult distal bypasses, in situ vein grafts demonstrated superior long-term patency compared to reversed saphenous vein, PTFE, and umbilical vein grafts, especially for below-knee and tibial anastomoses.
Area of Science:
- Vascular Surgery
- Biomaterials Science
- Clinical Trials
Background:
- Graft material selection is critical for the long-term success of difficult distal bypass procedures.
- Previous studies have shown variable outcomes for different graft types in peripheral arterial disease.
- Understanding long-term patency rates is essential for optimizing surgical strategies.
Purpose of the Study:
- To compare the 3-year patency rates of four different graft types used in difficult distal bypass surgery.
- To evaluate the influence of distal anastomosis site and patient factors on graft patency.
Main Methods:
- A multicenter trial involving 249 difficult distal bypasses.
- Graft types included in situ (IS) vein, reversed saphenous (RS) vein, polytetrafluoroethylene (PTFE), and umbilical vein (UV).
- Patency rates were assessed at 3 years, with subgroup analysis based on anastomosis site and patient characteristics.
Main Results:
- In situ vein grafts showed the highest primary (84%) and secondary (90%) patency rates at 3 years.
- Significant differences in patency were observed below the knee, favoring vein grafts (IS and RS) over synthetic grafts (PTFE and UV).
- Graft type was the most significant factor influencing patency, with its impact increasing at more distal anastomosis sites. Tobacco use was also a significant negative predictor.
Conclusions:
- In situ vein grafts are superior to reversed saphenous vein, PTFE, and umbilical vein grafts for difficult distal bypasses, particularly for below-knee and tibial anastomoses.
- Graft selection is paramount, and its influence is amplified with increasing distal anastomosis complexity.
- Further research should focus on optimizing vein graft utilization and exploring strategies to improve outcomes with synthetic grafts.
Abstract:
Two hundred forty-nine well-characterized difficult distal bypasses, entered into a multicenter dextran 40 trial, were reevaluated after 3 years. Seventy in situ (IS) vein grafts, 49 reversed saphenous (RS) vein grafts, 60 polytetrafluoroethylene (PTFE) grafts, and 70 umbilical vein (UV) grafts were used. Primary and secondary patency rates at 3 years were, respectively, 84% and 90% for IS, 66% and 73% for RS, 35% and 48% for PTFE, and 24% and 32% for UV. Subgroup analysis according to the site of distal anastomosis showed no significant differences in primary patency among these grafts at the above-knee level but significant differences between both vein grafts (IS and RV) and the others (PTFE and UV) below the knee (78% vs 31%, respectively). This difference increased at the tibial level (78% vs 10%) but there was also a significant difference between IS grafts (88%) and RS grafts (63%) at this level. Hazard functional analysis showed all grafts except IS grafts begin to fail at an increasing rate again by 24 months. Although overall results appeared to favor PTFE over UV, 62% of PTFE vs 16% of UV terminated at the above-knee level and the patency results of these two grafts were not significantly different at any level. The only other factor than graft type and distal anastomotic site that consistently correlated with late patency was tobacco use. Diabetic patients actually fared significantly better than nondiabetic patients, presumably because of the higher use of IS grafts and lower use of tobacco. The choice of graft overshadows all other factors affecting patency and its influence is magnified with more distal terminal anastomosis.