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.
OBJECTIVE
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.


CONCLUSIONS
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.
Scandinavian Miller Collar Study, Sweden. fredrik.bg.lundgren@gmail.com
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Lundgren
D000368:Aged; D000369:Aged, 80 and over; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D016009:Chi-Square Distribution; D005260:Female; D005263:Femoral Artery / Q000503:physiopathology / Q000601:surgery*; D006083:Graft Occlusion, Vascular / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D007511:Ischemia / Q000503:physiopathology / Q000601:surgery*; D053208:Kaplan-Meier Estimate; D035002:Lower Extremity / Q000098:blood supply*; D008297:Male; D015999:Multivariate Analysis; D011138:Polytetrafluoroethylene; D011150:Popliteal Artery / Q000503:physiopathology / Q000601:surgery*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011474:Prosthesis Design; D018570:Risk Assessment; D012307:Risk Factors; D013548:Sweden; D013997:Time Factors; D016896:Treatment Outcome; D014654:Vascular Patency; D014680:Veins / Q000503:physiopathology / Q000601:surgery
D011138:Polytetrafluoroethylene