Do Arterial and Venous Diameter Predict the Success of Wrist Radiocephalic Arteriovenous Fistula for Haemodialysis?: A Prospective Interventional Study

Introduction: Native or autogenous Arteriovenous Fistula (AVFs) placed for Chronic Kidney Disease (CKD) is the gold standard. Radiocephalic Arteriovenous Fistula (RCAVF) just proximal to the wrist is preferred, as it provides a larger proximal area for cannulation and can be created using End-to-Side (E-S) and Side-to-Side (S-S) techniques with good patency. Diameters of the radial artery and cephalic vein have been shown to produce predictable results in RCAVF. The distance between the radial artery and the cephalic vein at wrist or even more proximal has not been studied previously and may be instrumental in choosing either of the two surgical techniques for RCAVF. Aim: To find the optimum diameters of radial artery and cephalic vein, evaluated by Colour Doppler Ultrasound (CDU) that predicted the success of wrist RCAVF in E-S and S-S RCAVF placement techniques for Haemodialysis (HD). Materials and Methods: This prospective interventional study was carried out in the Departments of Plastic Surgery and Nephrology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Eastern Uttar Pradesh, India, from January 2019 to June 2021, to study 62 fistula in 52 patients of CKD in whom wrist RCAVF, as vascular access for HD, was constructed. The variables studied were calibre of radial artery and cephalic vein and their bearing on the surgical outcome in E-S and S-S surgical techniques. Further distance between radial artery and cephalic vein (in mm) at the wrist were meticulously studied to find its significance in both E-S and S-S surgical techniques. The outcomes measured were fistula usability (time from AVF placement to fistula maturation and subsequent functional use for HD) and AVF patency three months postoperatively. Significance of comparative variables was studied by two-tailed t-test. Results: In the present study, average age was 46.86 +/- 14.85 years and 37 patients were males while 15 were females. Mean diameter of radial artery was 2.14 +/- 0.48 mm while it was 2.12 +/- 0.49 mm in E-S and 2.16 +/- 0.45 mm in S-S technique (p-value=0.309). Mean diameter of cephalic vein was 2.24 +/- 0.64 mm, 2.26 +/- 0.67 mm in E-S and 2.22 +/- 0.61 mm in S-S technique (p-value=0.734). The distance between the both artery and vein was 5.77 +/- 4.06 mm. Thirteen RCF failed to mature (25%), 10 of these underwent secondary surgery for AVF. RCAVF became usable for HD after 7.70 +/- 1.12 weeks in E-S group and 7.59 +/- 1.19 weeks in S-S group (p-value=0.592). Primary AVF patency was 90.9% in E- S and 92.6% in S-S procedures at three months after surgery when the radial artery and cephalic vein were both larger than 2 mm. If the arteriovenous distance is less than 3 mm, the fistula can be treated using the S-S approach, and if it is greater than 3 mm, the E-S technique. Conclusion: This study demonstrated association between cephalic vein and Radial Artery Diameter (RAD) (>2 mm) with good three months RCAVF patency. It was shown that the distance between the radial artery and cephalic vein at the wrist serves as a criterion for using either the S-S or E-S surgical procedures.