Comparative clinical and histopathological evaluation of mature and nonmature arteriovenous fistula

Introduction: Nonmaturation of arteriovenous fistula (AVF) is a common obstacle due to neointimal hyperplasia (NIH). The present study evaluated the clinical and histopathological factors predicting AVF nonmaturation. Methodology: This prospective observational study was conducted over 18 months in 100 patients. AVF site venous tissue samples of 55 4/5 chronic kidney disease stages patients were collected. Histopathological analysis was done to detect four immunohistochemistry (IHC) markers, namely cluster of differentiation (CD68), CD31, α-SMA, and Ki67. IIntimal composition, hyperplasia, and calcification were also assessed. Fistulae were followed up at the 2nd, 6th, and 12th weeks and classified into mature and nonmature groups at 12 weeks based on clinical and Doppler examination. A comparison between the two groups was done and an association of radiological, histopathological, and IHC parameters of nonmature AVF was also carried out. Results: Among 55 patients, 35 (63.6%) had mature AVF and 26 (47%) had preexisting NIH. Preexisting NIH had no significant association with maturation (odds ratio: 0.44). Subjects without preexisting NIH had a significantly higher luminal diameter in 2nd week (P ≤ 0.05). There was a significant increase in blood flow both between the 2nd and 6th and between the 6th and 12th week (P < 0.05). Of the four IHC markers, three markers viz., CD68 (ρ = 0.525), CD31 (ρ = 0.420), and α-smooth muscle actin (ρ = 0.718) correlated significantly (P < 0.05) with the NIH. The mean AVF diameter and blood flow in the matured arm were more than that in the nonmatured arm at all the follow-ups (P < 0.09). Conclusion: The presence of CD68, CD31, and α-smooth muscle actin in the venous tissue suggests preexisting NIH which postoperative luminal diameter and blood flow may have long-term consequences in AVF functioning.