The hidden burden of high-flow fistulae in a home haemodialysis programme : outcomes of initiating arteriovenous fistula monitoring in the home haemodialysis population

Home haemodialysis (HHD) is common in Australia. The majority of these patients dialyse using an arteriovenous fistula (AVF). AVFs are a potential source of morbidity: low fistula flow may result in inadequate dialysis; high flow may lead to cardiac failure. Whilst intradialytic measures of fistula performance are available in many haemodialysis centres, HHD patients are particularly vulnerable to unrecognised access dysfunction. To address the needs of this population for access monitoring, a structured programme of surveillance utilising ultrasound dilution was introduced. This allowed us to determine the prevalence and type (high/low flow) of access dysfunction. Over a three-year period, 141 patients had flow measurements, with cardiac output (CO) also measured where possible. All patients dialysed through an AVF. Forty-one patients (29%) were identified with access dysfunction. Nineteen patients (13.5%) had low-flow AVF (access flow (Qa) <500ml/min) and 22 patients (15.6%) had evidence of high flow (Qa >2L/min, CO >8L/min or Qa:CO >0.3). Upper arm AVF were more likely to be high flow than radiocephalic (p<0.001). Most patients with low-flow AVF underwent stenting (17/19), and 10 patients with high-flow AVF had banding to reduce the size. We identified a high prevalence of undetected AVF dysfunction that could result in significant morbidity, particularly related to high-flow AVF that may be clinically silent. We support the use of regular AVF surveillance in the HHD population using ultrasound dilution as a simple and effective way of identifying dysfunctional AVF to allow early intervention and reduced future morbidity.