The effect on patency of type, shape and volume of a vein collar used at the distal anastomis of PTFE-bypass to arteries below-knee.

AIM: The aim of this paper was to study the effect on patency rate of different types of vein collar (Miller's original or St Mary's boot), different length/height shapes of vein collar, and different vein collar volumes at the distal anastomosis of PTFE-bypass grafts to below-knee arteries in patients with critical limb ischemia.

METHODS

One hundred eighty patients operated on with PTFE-bypass to below-knee arteries with a vein collar at the distal anastomosis were analyzed. They were recruited from a prospective randomized trial evaluating the effect of adding a vein collar to the distal anastomosis. Primary patency rate of the reconstructions were assessed against three factors: the type, shape, and volume of the vein collar. Univariate analysis was performed with the help of plotted Kaplan-Meier lifetable curves and log-rank tests and multivariate analysis with Cox proportional hazards regression.

RESULTS

Type of vein collar had no influence on primary patency (logrank-test, χ(2)=0.8, df=1, P=0.377, N.=180). A length/height ratio of the vein collar between 1.18 and 1.63 were advantageous for primary patency but the effect was not statistically significant (logrank-test, chisq=5.5, df=2, P=0.063, N.=177). A large volume of the vein collar enhanced primary patency (logrank-test, chisq=6, df=2, P=0.050, N.=173). In the multivariate analysis, however, a larger volume and a length/height ratio between 1.18 and 1.63 as well as > 1.63 reduce the risk of graft failure with 48% (P=0.00006), 58% (P=0.007), 58% (P=0.004), respectively, while vein collar type had no effect on primary patency.

CONCLUSION

This prospective observational study indicates that if a vein collar is used at the distal anastomosis of a PTFE-bypass to below-knee arteries it should be long compared to height and large in volume to improve primary patency rate, while the type of vein collar does not appear to matter.