In an observational cohort study of Medicare beneficiaries receiving haemodialysis, the use of an arteriovenous graft (AVG) compared with an arteriovenous fistula (AVF) was associated with an increased risk of deep vein thrombosis (DVT) and/or pulmonary embolism (PE). Conversely, researchers also found that there was little to no difference according to the access type in the rates of major bleeding or other cardiovascular outcomes. These results were recently published in Kidney Medicine.
In their report, authors Nicholas S Roetker (Hennepin Healthcare Research Institute, Minneapolis, USA) and colleagues write that the risks of major bleeding, thrombosis, and cardiovascular events are elevated in patients receiving maintenance haemodialysis. The team’s objective was to compare the risk of these outcomes in haemodialysis patients according to the permanent vascular access type.
Using data from the United States Renal Data System (2010–2015), the researchers included in their study patients with kidney failure who were greater than 18 years, had Medicare as the primary payer, were not using an oral anticoagulant, and were newly using an arteriovenous (AV) access for haemodialysis.
Roetker et al compared 17,763 AVG and 60,329 AVF users, estimating the three-year incidence rates and incidence rate ratios (IRRs) of various outcomes, specifically major bleeding, venous thromboembolism (VTE), ischaemic stroke, myocardial infarction, cardiovascular death, and chronic limb-threatening ischaemia.
In Kidney Medicine, the authors report that the use of an AVG, compared with that of an AVF, was associated with an increased risk of VTE (10.8 vs. 5.3 events per 100 person-years; adjusted IRR, 1.74; 95% confidence interval [CI], 1.63–1.85) but not with the risk of major bleeding (IRR, 1.04; 95% CI, 0.93–1.17). They add that the use of an AVG was also potentially associated with a slightly increased risk of cardiovascular death (IRR, 1.09; 95% CI, 1.01–1.16).
The investigators acknowledge some limitations of their study, noting for example that the analysis included only patients with a functioning AV access, and that the scope of outcomes considered provides an “incomplete picture” of the risks facing AV access users. “While this analysis was primarily concerned with assessing bleeding, thrombotic, and cardiovascular events, the risk of a variety of other serious clinical outcomes should be considered when choosing a vascular access,” they write. Furthermore, the authors note that their study included Medicare fee-for-service beneficiaries with Part D coverage who were not receiving oral anticoagulation; as such, they comments that “the results may not be generalisable to other kidney failure populations”.
In their conclusion, Roetker and colleagues summarise that the use of an AVG, relative to an AVF, in haemodialysis is associated with an increased risk of VTE. They remark on the implications of these findings: “Given recent guidelines emphasising selection of the ‘right access’ for the ‘right patient,’ the results of this study should potentially be considered as one additional factor when selecting the optimal access for haemodialysis”.