Randomised clinical study of the impact of routine preoperative Doppler ultrasound for the outcome of autologous arteriovenous fistulas for haemodialysis

BACKGROUND: Arteriovenous fistulas are the gold standard of vascular accesses in haemodialysis; however, they have a considerable primary failure rate. This study evaluated the comparative reliability of routine preoperative Doppler ultrasound with an isolated physical examination of autologous arteriovenous fistulas within the Single Health System of Brazil and analysed the potential clinical benefit, improvement in primary failure rates and its economic impact. METHODS: A non-blind randomised clinical study group of patients undergoing a vessel mapping with preoperative Doppler ultrasound (ultrasound group) and a control group who had undergone only a physical examination (clinical group) before the vascular procedures was performed. The role of the arteriovenous fistula in dialysis and possible alterations was evaluated in both the groups and followed up for 6 months. RESULTS: Of the initial 248 eligible patients, there was a randomisation of 230 patients, 228 of whom were submitted for surgery, 114 in each group. In the clinical group, a significantly higher rate of primary failure was recorded, with 13.6% versus 4.4% in the ultrasound group (p = 0.002). The Kaplan–Meier curve with log-rank analysis showed a significantly higher primary patency in the ultrasound group (p = 0.042). Regarding the cost-effectiveness of the use of Doppler ultrasound, there was no increase in the final cost compared to the physical examination (US$1.28/fistula day × US$1.29/fistula day). CONCLUSION: It was concluded that Doppler ultrasound contributed to the reduction of primary failure, leading to a significantly superior primary patency of arteriovenous fistulas, and no increase in the final cost. This justifies its routine preoperative use in the Single Health System. Registration number RBR-474xhn (http://www.ensaiosclinicos.gov.br).