Abstract: TH-PO768

Postoperative Vascularization of the Arteriovenous Fistula Is Not Associated with Maturation: A Pilot Study

Session Information

Category: Dialysis

  • 603 Hemodialysis: Vascular Access

Authors

  • Duque Ballesteros, Juan Camilo, University of Miami, Miller School of Medicine, Miami, Florida, United States
  • Martinez, Laisel, University of Miami, Miller School of Medicine, Miami, Florida, United States
  • Paez, Angela, University of Miami, Miller School of Medicine, Miami, Florida, United States
  • Tabbara, Marwan, University of Miami, Miller School of Medicine, Miami, Florida, United States
  • Selman, Guillermo, Albany Medical College, Albany, New York, United States
  • Salman, Loay H., Albany Medical College, Albany, New York, United States
  • Vazquez-Padron, Roberto I., University of Miami, Miller School of Medicine, Miami, Florida, United States
Background

The venous vasa vasorum provides oxygen and nutrients to the walls of native veins and arteriovenous fistulas (AVF). Nonetheless, whether expansion or growth of the AVF microvasculature has an effect on clinical outcomes remains undetermined. The purpose of this study was to evaluate the association of AVF vascularization with maturation and with the development of medial fibrosis and intimal hyperplasia (IH).

Methods

We assessed pre-existing and postoperative vascularization in both native veins and AVF venous samples (i.e., tissue pairs) from 19 patients undergoing two-stage AVF creation. Patients with successful maturation (N=9) and maturation failure (N=10) were matched with respect to age, demographics, and comorbidities. Vasa vasorum density (VVD; microvessel count/wall area) and area (VVA; microvessel luminal area/wall area) were quantified in the vascular layers of CD31-stained cross-sections. Change in vascularization after AVF creation was calculated by subtracting pre-existing VVD and VVA from the postoperative values in tissue pairs.

Results

Total VVD in native veins was 6/mm2 (interquartile range [IQR] 2-10), with no significant change in AVFs as determined by pairwise comparisons (p=0.3). Total VVA increased during remodeling, from 956 um2/mm2 (IQR 509-1466) in native veins to 1879 um2/mm2 in AVFs (IQR 766-2578; p=0.046), with the most significant increase observed in the adventitia (1751 vs. 4798, respectively; p=0.004). AVF vascularization was not associated with baseline factors (age, ethnicity, sex, diabetes), nor with the time interval between AVF creation (first-stage) and transposition (second-stage) surgeries. Interestingly, although IH increased significantly in AVFs compared to veins (p=0.0003), microvessels were detected in the intima of only four AVFs and not in veins, and neither VVD nor VVA was associated with the degree of IH. Similarly, none of the vascularization parameters measured were associated with medial fibrosis. Lastly, there were no significant differences in VVD or VVA between AVFs with distinct maturation outcomes.

Conclusion

This study indicates that AVF vascularization is not a major contributing factor in remodeling after access creation, and it does not determine maturation.

Funding

  • NIDDK Support