Pathological Analysis of Vascularization of the Arterialized Veins in Failed Arteriovenous Fistulae.

PURPOSE:To assess venous wall vascularization and its correlation with neointimal hyperplasia (NIH) in failed arteriovenous fistulae (AVFs). MATERIALS AND METHODS:A total of 43 uremic patients who underwent de novo AVF creation and 39 patients who underwent reconstruction of failed fistulae were enrolled in the study. A 5-10-mm vein segment adjacent to the future fistula creation or reconstruction site was surgically removed and assessed using histopathological analyses and stained by immunohistochemistry to quantify vasa vasorum density (VVD). RESULTS:Both the intimal thickness (70.68 [28.81-99.54] vs 4.53 [2.69-7.30] μm, P < .001) and the intimal thickness-to-medial thickness ratio (2.20 [0.77-4.36] vs 0.15 [0.10-0.30], P < .001) were higher in failed AVFs than in preaccess veins. CD31- and factor VIII-marked VVDs in both the intima (6.31 [1.62-12.53] vs 0.0 [0.0-0.0], P < .001; 7.82 [3.33-11.61] vs 0.0 [0.0-0.0], P < .001) and media (10.0 [7.59-12.95] vs 3.71 [2.44-4.87], P < .001; 8.33 [5.55-13.0] vs 3.57 [2.53-4.82], P < .001) as well as the intimal VVD:medial VVD ratio (0.67 [0.19-1.08] vs 0.0 [0.0-0.0], P < .001; 0.71 [0.39-1.14] vs 0.0 [0.0-0.0], P < .001) were significantly higher in failed AVFs than in preaccess veins. Moreover, there was a positive relationship between the intimal VVD:medial VVD ratio and the intimal thickness:medial thickness ratio (P < .001). In addition, the vascular endothelial cell growth factor A expression was higher in failed AVFs than in preaccess veins. CONCLUSIONS:Vascularization of the vessel wall was noticeably more developed in the arterialized veins, especially at the NIH regions in failed AVFs.