Risk of Vascular Access Complications with Frequent Hemodialysis

Frequent hemodialysis requires using the vascular access more often than with conventional hemodialysis, but whether this increases the risk for access-related complications is unknown. In two separate trials, we randomly assigned 245 patients to receive in-center daily hemodialysis (6 days per week) or conventional hemodialysis (3 days per week) and 87 patients to receive home nocturnal hemodialysis (6 nights per week) or conventional hemodialysis, for 12 months. The primary vascular access outcome was time to first access event (repair, loss, or access-related hospitalization). Secondary outcomes were time to all repairs and time to all losses. In the Daily Trial, 77 (31%) of 245 patients had a primary outcome event: 33 repairs and 15 losses in the daily group and 17 repairs, 11 losses, and 1 hospitalization in the conventional group. Overall, the risk for a first access event was 76% higher with daily hemodialysis than with conventional hemodialysis (hazard ratio [HR], 1.76; 95% confidence interval [CI], 1.11–2.79; P=0.017); among the 198 patients with an arteriovenous (AV) access at randomization, the risk was 90% higher with daily hemodialysis (HR, 1.90; 95% CI, 1.11–3.25; P=0.02). Daily hemodialysis patients had significantly more total AV access repairs than conventional hemodialysis patients (P=0.011), with 55% of all repairs involving thrombectomy or surgical revision. Losses of AV access did not differ between groups (P=0.58). We observed similar trends in the Nocturnal Trial, although the results were not statistically significant. In conclusion, frequent hemodialysis increases the risk of vascular access complications. The nature of the AV access repairs suggests that this risk likely results from increased hemodialysis frequency rather than heightened surveillance.Establishing and maintaining a suitable vascular access for hemodialysis has long been considered the Achilles heel of hemodialysis. Any intervention that potentially increases risk to the vascular access must be carefully evaluated.Frequent hemodialysis provides multiple physiologic and quality-of-life benefits to patients with ESRD. The Frequent Hemodialysis Network (FNH) Daily Trial showed that, compared with conventional thrice-weekly hemodialysis, in-center hemodialysis performed 6 days per week improved self-reported health-related quality of life, left ventricular mass, and several other surrogate outcomes.¹ Similar improvement trends have been seen with nocturnal hemodialysis performed 6 nights per week.^2,3 Yet despite these demonstrated benefits, frequent hemodialysis may have potential risks. Compared with conventional hemodialysis, frequent hemodialysis requires using the vascular access up to twice as often. In addition to direct trauma caused by more frequent venipuncture of arteriovenous accesses, more frequent access use could theoretically result in increased endothelial trauma due to shear forces created by returning blood, more inflammation, and greater exposure to bacterial pathogens. These factors, in turn, could cause more access stenosis, thrombosis, and infection. In the FHN Daily Trial and Nocturnal Trial, we tested the hypothesis that both types of frequent hemodialysis would increase the risk of vascular access complications.