title: The use of an adjuvant arterio-venous shunt in prosthetic femoro-crural bypass.
abstract: In limb threatening ischaemia the use of a long prosthetic graft to the distal calf vessels may be the only alternative to a primary amputation. Patency rates in these situations are relatively poor and the use of an adjuvant arteriovenous fistula (AVF) at the distal anastomosis to increase the velocity of flow above the thrombotic threshold seems logical. We present follow-up of up to 8 years in a series of 80 consecutive reconstructions to the distal crural vessels using human umbilical vein with an adjuvant AVF. The mean age of the patients was 68.3 years and 12 (15%) were diabetic. The indication for surgery was limb threatening ischaemia in all cases; 41 (51.2%) for established necrosis and the remaining 39 (48.8%) for severe ischaemic rest pain. The mean ankle:brachial index was 0.23. The common ostium (CO) configuration of AVF was used in 50 cases (62.5%) and pre-anastomotic in 30 cases (37.5%). The volume blood flow in 49 cases, measured peroperatively using an electromagnetic flowmeter, was 116 ml/min (+/- 62.5) with the shunt closed and 283 ml/min (+/- 132.2) with the shunt open (p less than 0.01, Student's t-test). Cumulative patencies of all grafts were 39% at 2 years and 29% at 4 years. The age of the patient and the type of AVF, common ostium or pre-anastomotic, had no significant effect on patency rates, but grafts under 70 cm in length had a cumulative patency at 2 years of 42.5% compared to 13.5% for those over 70 cm in length (p less than 0.01). Cumulative patencies were derived by life table analysis and compared using the log rank test. The size of the recipient vessels at the distal anastomosis is thought to be crucial to the outcome of these operations. An increase in velocity of flow produced by an AVF, increases the wall shear stresses at this site and may lead to an increased tendency for intimal hyperplasia. It may be possible to mitigate these effects by the use of additional surgical or pharmacological techniques and further studies are required.
authors.affiliation: Department of Vascular Surgery, Broadgreen Hospital, Liverpool, UK.
authors.forename: A P
authors.initials: AP
authors.lastname: Moody
authors.forename: S
authors.initials: S
authors.lastname: al Fagih
authors.forename: P R
authors.initials: PR
authors.lastname: Edwards
authors.forename: H
authors.initials: H
authors.lastname: Campbell
authors.forename: P L
authors.initials: PL
authors.lastname: Harris
mesh_terms: D001166:Arteriovenous Shunt, Surgical / Q000379:methods*; D001807:Blood Vessel Prosthesis; D005263:Femoral Artery / Q000601:surgery*; D006801:Humans; D007511:Ischemia / Q000601:surgery*; D007866:Leg / Q000098:blood supply*; D014471:Umbilical Veins / Q000637:transplantation*; D014654:Vascular Patency