Hemodialysis arteriovenous fistula maturation and role of perioperative vascular mapping

Introduction: The arteriovenous fistula (AVF) is the preferred access in patients starting on maintenance hemodialysis. The vasculature of the upper limb has a dominant role in determining the successful outcome of AVF surgery. Hence, we aimed to determine the various vascular parameters both preoperatively and postoperatively at prespecified intervals and their impact on AVF outcomes. Materials and Methods: It was a prospective observational study done during 18 months period. Ultrasound with doppler color flow evaluation was done to look for radial artery diameter, cephalic vein diameter, radial artery flow, and peak systolic velocity both preoperatively and postoperatively at postoperative day 1 (POD) 1, 8 weeks, and 3 months. Results: A total of 120 patients were evaluated with a mean age of 50.2 ± 12.01. The male: female ratio was 2.75:1. The etiology of the end-stage renal disease was diabetes-related in 41.6% and the remaining 58.4% were of nondiabetic. The overall success rate was 68.3%, with 31.7% failure rate. On comparison between the successful and failed AV fistula groups, a statistically significant difference was found in relation to the pre and post procedural vascular diameter and flow rates between the groups. The mean cephalic vein diameter in those with successful AVF was 2.17 mm and 1.90 mm in those with a failed AVF. Conclusion: In our study, the Cephalic vein size, radial arterial diameter, peak systolic velocity, radial artery flow rate preoperatively, and increase in flow rate at POD1 and POD 8 along with the increase in cephalic vein diameter were the predominant factors determining the success of the radiocephalic fistula. This is strong evidence that routine preoperative duplex ultrasonography reduces the rate of primary fistula failure and unnecessary surgical exploration when used for selection of vessels for AVF preoperatively as well as postoperative monitoring of AVF during the period of follow-up. A minimum arterial diameter of 2 mm is associated with successful fistula formation. Below this diameter, the ability of an artery to increase flow and dilate will determine fistula success.