Intimal CD31-positive relative surfaces are associated with the dysfunction of autologous arteriovenous fistulas in patients receiving dialysis

Objective: This study aimed to evaluate the association between specific histological features of the cephalic vein, assessed intraoperatively, for subsequent dysfunction of primary radiocephalic arteriovenous fistulas (RCAVFs). Methods: In a retrospective cohort analysis, 170 patients undergoing first-time RCAVF creation were included. A segment of the cephalic vein had been harvested during surgery and was subjected to standardized histopathological analysis. Key parameters were quantified using digital morphometry and immunohistochemistry: medial microvascular density (CD31-positive relative surface area), intimal thickness, and medial collagen fiber orientation via second-harmonic generation microscopy. AVF failure was defined as the inability to use the fistula successfully for dialysis within 12 months postoperatively. Univariate and multivariate logistic regression, ROC analysis, and restricted cubic spline models were employed to identify and characterize predictors. Results: During the follow-up, 40 patients (23.5%) experienced AVF failure. In multivariate analysis, only a larger medial CD31-positive relative surface area remained a significant independent predictor of failure (odds ratio = 1.48 per 0.1% increase, 95% CI 1.15–1.90, P < 0.01). Intimal thickness showed a significant but weaker linear association. The CD31-positive area provided the highest individual predictive accuracy (AUC = 0.78), and a model combining it with intimal thickness achieved an AUC of 0.82. Nonlinear analysis revealed a threshold effect for CD31, with risk plateauing beyond a density of approximately 1.7%. Collagen fiber orientation was not associated with outcomes. Conclusions: Intraoperative medial microvascular density of the cephalic vein is a robust, independent histopathological maker associated with AVF failure. This finding underscores the importance of the pre-existing biological state of the venous wall, offering a novel biomarker that may refine risk stratification and shift focus toward biological mechanisms in vascular access management.