Vitamin D and Arteriovenous Fistulae

Hemodialysis vascular access dysfunction is a major source of morbidity and cost among ESRD patients, accounting for up to 25% of all hospital stays, and 50% of all costs within the first year of initiating dialysis.The AVF provides higher blood flow rates, fewer thrombotic and infectious complications, and lower morbidity and cost compared with prosthetic grafts or central venous catheters.However,up to 50% of newly created AVF's fail to mature sufficiently for chronic hemodialysis use. Clearly, determining factors predictive of poor AVF maturation are important from both patient care and health policy perspectives and are worthy of investigation.

Vitamin D has antiproliferative, antioxidant and antiangiogenic properties. The observed association of vitamin D deficiency and increased risk of cardiovascular and peripheral vascular disease may extend to the vasculature used in the creation of an AVF.

As renal function worsens, patients with chronic kidney disease (CKD) produce less vitamin D, due to impaired renal conversion of 25-hydroxy- to 1,25-dihydroxyvitamin D by declining renal 1-alpha hydroxylase. As a result, at the time of dialysis initiation,78%-90% of ESRD patients are vitamin D deficient. Until recently, vitamin D deficiency among CKD and ESRD patients was only treated if hyperparathyroidism was present, however, more attention is now paid to nutritional vitamin D deficiency given its association with a range of comorbid conditions.Furthermore, 1,25-dihydroxyvitamin D and its analogue compounds are associated with improved survival in the CKD and ESRD populations. We believe that the observed benefits of vitamin D may improve AVF maturation among a population in which vitamin D deficiency is highly prevalent.