Impact of tibial bypass conduit on long-term amputation-free survival and primary patency in the Vascular Quality Initiative

Objective: Much research remains focused on tibial bypass conduit selection. We sought to describe long-term amputation-free survival (AFS) and primary patency (PP) of patients undergoing tibial bypass by conduit type and configuration across several permutations in the Society for Vascular Surgery Vascular Quality Initiative. Methods: Patients in the Vascular Quality Initiative registry undergoing elective first-time femoral- or popliteal-to-tibial bypass for occlusive disease involving rest pain or tissue loss were identified. Prior ipsilateral infrainguinal bypass or concomitant procedures were excluded. Outcomes of interest included patient AFS at 22 months and PP at 1 year (defined as freedom from revision, thrombectomy, or graft occlusion). Results: A total of 4192 bypasses were identified. The majority utilized great saphenous vein (GSV) (76.2%), followed by polytetrafluoroethylene (10.6%), nonautologous biologic (6.5%), composite (3.3%), arm vein (2.8%), and small saphenous vein (0.6%). Compared with all prosthetic and composite bypasses, vein grafts had the best AFS (76.4%; P < .0001) and PP (68.1%; P = .041). Of the single segment vein conduits, GSV bypasses had the best PP (69.1%) and arm vein the worst (60.2%). AFS and PP were similar between single-segment GSV orientations. Single-segment GSV bypasses exhibited better PP than multiple segment bypasses (69.1% vs 54.6%; P = .0016). PP was significantly better for polytetrafluoroethylene compared with nonautologous biologic (68.4% vs 51.2%; P = .0039). PP did not significantly differ between vein cuff for prosthetic bypass compared with no vein cuff (69.1% vs 59.7%; P = .091). PP was not significantly different between single-segment GSV and prosthetic grafts with vein cuff (69.1% vs 69.1%; P = .51). There were no significant differences in AFS comparing arm vein, prosthetic bypass with vein cuff, or composite grafts (67.2% vs 63.8% vs 59.3%; P = .092), as well as in PP (60.2% vs 69.1% vs 54.8%; P = .14). Conclusions: Single-segment vein bypass was only marginally the most optimal conduit. Surprisingly, there may be more equipoise among conduit types, particularly in the absence of adequate GSV. Prosthetic grafts overall may not be as disadvantaged in the long term as initially thought, especially when compared with arm vein, as prosthetic bypass with vein cuff did not significantly differ in PP. Similarly, a composite conduit may not impact long-term outcomes. These data suggest that conduit choice may not impact outcomes to the degree previously thought and that other factors may have a greater impact than presumed, especially in conduit limited situations.