Sites of stenosis in AV fistulae for haemodialysis access

A large proportion of late failures of radiocephalic arteriovenous fistulae are related to the progression of intimal hyperplasia. The aetiology of this process is still unknown but the fistula configuration and resultant haemodynamics have been implicated. This clinical study was devised to identify sites of stenosis in patients with fistulae and relate the findings to various clinical and geometrical parameters. Measurement of anastomotic length and angle was made intraoperatively in 25 consecutive fistulae. Post-operative assessment was carried out at regular intervals using duplex and colour-flow ultrasonography. Stenoses were present in all 25 of the fistulae studied at 3 months. The stenoses could be classified to three specific sites: at the anastomosis (Type 1), on the inner wall of the curved region of the cephalic vein (Type 2) and just proximal to this curved segment where the vein straightens out (Type 3). Most of Type 1 and Type 2 stenoses were not progressive while Type 3 stenoses were generally progressive. These findings emphasize the need for an effective surveillance programme of AV fistulae.