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

To assess venous wall vascularization and its correlation with neointimal hyperplasia (NIH) in failed arteriovenous fistulae (AVFs).

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).

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.

Vascularization of the vessel wall was noticeably more developed in the arterialized veins, especially at the NIH regions in failed AVFs.