A Trial of Interrupted vs Continuous Suturing Techniques for Radiocephalic Fistulae

Overview

Patients with end-stage renal failure require dialysis to remove toxins from their blood. Haemodialysis is best provided through a native arterio-venous fistula (AVF). Creation of an AVF requires a short (\~1hr) surgical procedure to join the artery and vein together. There are limited potential sites for fistula creation. Generally it is preferrable to utilise the most distal sites at the wrist first, as more proximal elbow procedures preclude subsequent use of the wrist should the initial fistula fail. The small diameter of artery and vein at the wrist requires precise surgical technique. There are two potential techniques in common use for creating the arterio-venous anastomosis (the join between artery and vein) - continuous suturing and interrupted sutures. Whilst there are theoretical advantages to the interrupted technique, it is uncertain if these translate clinically into better success of creating the fistula. The aim of this study is therefore to compare the clinical success of the two techniques.

The micro-vascular anastamosis required for creation of a radio-cephalic arteriovenous fistula, is technically challenging surgery. Primary patency rates for radiocephalic fistula varying between 50-75% in the literature and 60-95% within over own department. It is important to optimise primary patency rates as initial failure subjects the patient to risks of further surgery and often necessiates them commencing dialysis via a tunnelled line (which is less effective and associated with increased risks of infection) whilst a second attempt at creating a fistula is undertaken. Multiple variations of both continuous and interrupted suture technique are described in the vascular literature, both in animal models of arterio-venous fistulae and in clinical studies in other specialities. However no study has compared the two techniques within clinical practice. Evidence from in vivo animal studies is variable. Several authors have shown no difference in primary patency rates achieved with continuous suture versus interrupted suture technique used for anastomosis(Chen \& Chen, 2001; Wilasrusmee et al 2007). Others have suggested that using a continuous suture causes a reduced cross-sectional area of the anastomosis compared to an interrupted technique (Tozzi \& Hayoz, 2001). Similarly an interrupted suture technique permits expansion of the vessel at physiological pressures where as continuous technique does not (Norbert \& Philip, 1996; Gerdisch \& Hinkamp, 2003). This loss of compliance at the anastomosis can in turn lead to intimal hyperplasia, causing poor blood flow and failure of the anastamosis (Dorbin, 1994), indicating potential theoretical benefits of interrupted suturing. There are no clinical studies comparing the two techniques and variation in practice varies considerably. The aim of this study therefore is the compare patency rates in radiocephalic fistulae by randomising to one or other anastomotic technique.