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, and subsequent dysfunction of primary radiocephalic arteriovenous fistulas (RCAVFs).

METHODS

In this retrospective cohort analysis, we analyse data from 170 consecutive patients with end-stage renal disease who underwent first-time RCAVF creation between January 2020 and November 2023, after applying predefined inclusion and exclusion criteria. 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

Within 12 months postoperatively, 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 potential histopathological biomarker associated with AVF failure in this retrospective cohort. This finding underscores the importance of the pre-existing biological state of the venous wall, offering a novel marker that may refine risk stratification and shift focus on biological mechanisms in vascular access management.