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INTRODUCTION: Despite advances in endovascular techniques, tibial bypass may still be required for revascularization to obtain healing and limb salvage. Perioperative (30 day) graft patency is an important outcome parameter reflecting technical considerations and acute graft thrombosis. Both are important prerequisites for long-term patency. In this analysis, we compare the 30-day patency of greater saphenous vein to alternative conduit configurations for tibial bypasses.
METHODS: The study cohort consisted of all primary tibial bypasses entered in a prospective, multicenter database (ACS-NSQIP) from 2006-2010 with exclusion of re-operative cases. The bypasses were divided into six groups, 1) greater saphenous vein (GSV), 2) prosthetic conduit, 3) prosthetic conduit with a distal anastomotic venous adjunct such as a cuff or patch, 4) composite graft of ePTFE and a vein segment, 5) spliced autogenous vein, and 6) arm vein. Thirty-day graft failure, patient demographics and operative details were compared among groups. Univariate associations between patient factors and conduit were tested and those variables that had p<.20 were used in a multivariate model to predict patency.
RESULTS: 5,375 tibial bypasses were analyzed by conduit; GSV 3,983 (74%), prosthetic 889 (17%), spliced vein 160 (3%), prosthetic with adjunct 112 (2%), arm vein 93(2%), composite 91 (2%). There was no difference among groups in terms of diabetes, renal failure, tobacco use, or rest pain as an indication for bypass. There was no difference in perioperative mortality based on conduit. After adjusting for gender, age, weight, race, and previous cardiac surgery (CABG), the bypass conduit had a significant independent association with 30 day graft patency (p=.006). The GSV failure rate was 7.5%. Composite grafts had a significantly higher 30-day failure rate (15.4%, p=0.006). There was no significant difference in 30-day patency of spliced vein (5.6%, p=0.37) or arm vein (4.3%, p=0.24) conduits compared to GSV. However, spliced vein and arm vein involved longer OR time and spliced vein increased transfusion requirements. Prosthetic grafts had significantly lower 30-day patency compared to GSV (10.5%, p=0.004). The addition of adjuvant venous tissue at the distal anastomosis of prosthetic bypasses did not significantly improve their 30-day patency (Prosthetic/venous adjunct graft failure rate 9.8% vs. PROSTHETIC graft failure rate 10.5%).
CONCLUSIONS: Venous conduits (GSV, spliced vein, arm vein) deliver the best perioperative patency for tibial bypass and GSV remains the most commonly used graft for tibial revascularization. Prosthetic grafts had a higher perioperative bypass failure rate. Composite grafts should be abandoned because their patency is not better than pure prosthetic conduits. The addition of a distal venous adjunct did not seem to improve acute prosthetic graft patency which may reflect lack of effect on thrombogenicity rather than the myointimal hyperplastic response that impacts long term failure of tibial bypass.

Patients'' Preoperative Variables and Perioperative Outcomes

	GSV	SPLICED VEIN	ARMVEIN	PROSTHETIC	PROSTHETIC/VENOUS ADJUNCT	COMPOSITE
n	3983	160	93	889	112	91
Female*	1,280 (32.2%)	49 (31.2%)	23 (24.7%)	315 (35.2%)	33 (29.7%)	39 (42.9%)
Age*	69.5±12.3	71.3±11.2	67.5±10.9	70.6±11.4	70.2±12.0	70.9±11.3
CABG*	874(21.9%)	55(34.4%)	43(46.2%)	311(34.6%)	41(36.6%)	22(24.2%)
Transfusion*	0.5±1.1	1.2±1.7	0.4±0.8	0.5±1.2	0.7±1.1	0.6±1.2
OR time (hrs)*	4.4±1.8	6.1±1.9	5.1±2.3	3.7±1.6	4.4±1.8	4.7±2.0
Mortality	127(3.2%)	4(2.5%)	2(2.2%)	40(4.5%)	1(0.9%)	4(4.4%)
30-day graft failure*	300 (7.5%)	9 (5.6%)	4 (4.3%)	94 (10.5%)	11 (9.8%)	14 (15.4%)
p value vs. GSV	--	0.37	0.24	0.004	0.37	0.006