The function of permanent vascular access

Complications arising from vascular access (VA) are major causes of morbidity in patients on renal replacement therapy (RRT). They contribute to frustration of health care providers and to high medical cost. To prevent failures in the future it will be helpful to identify the factors that are related to VA malfunction.

In a retrospective analysis we analysed the types, duration and primary rate of patency of 1033 permanent vascular accesses in 544 consecutive patients established during a 13-year period in a tertiary care hospital. Patient characteristics, incidence, and risk factors related to VA failure were registered. In addition, VA outcomes in patients who started haemodialysis with a catheter and in whom initial VA failure occurred were analysed separately.

Forty-five per cent of patients required a central catheter at the start of HD, but 92% of them were being dialysed with an a-v fistula at the last observation. The total number of complications was 0.24 episodes per patient per year at risk and the rate of thrombosis 0.1. A total of 52% of patients were dialysed throughout the observation period with their initial a-v fistula; 9.3% had more than three episodes of VA failure. The radiocephalic a-v fistula was the VA with the best median duration, exceeding 7 years, but also the type that had the highest initial failure rate, i.e. 25% of patients and 13% of the events. The brachiocephalic a-v fistula was the second most frequent type of VA, with a median duration of function of 3.6 years, in contrast to the humerobasilic a-v fistula, which exceeded 5 years. Average patency of the different types of grafts did not exceed 1 year, with the exception of the autologous saphenous graft with a median duration of function of 1.4 years. Patients with glomerulonephritis had the best function rates for their VA, the median exceeding the duration of the study, whereas in half of the diabetic patients it was less than 1 year. The duration of patency of the VA was twice in patients below age 65 years and in elderly males compared to elderly females. Patients who started HD with a catheter, as well as those with initial VA failure, had a higher rate of VA failure in the subsequent course on RRT.

The radiocephalic and the humerobasilic a-v fistulae are the two types of VA with the longest duration of function, although a high rate of initial failure is seen with the radiocephalic a-v fistula. Age, female gender, presence of diabetic nephropathy, start of dialysis with a catheter, and failure to wait for initial maturation of the VA are risk factors, and account for the majority of VA failures during RRT.