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Abstract: SU-OR28

Hemodynamics and Geometry of Rat Arteriovenous Fistulas: Effect of Sildenafil Treatment

Session Information

Category: Dialysis

  • 704 Dialysis: Vascular Access

Authors

  • Northrup, Hannah M., University of Utah, Salt Lake City, Utah, United States
  • Shiu, Yan-Ting Elizabeth, University of Utah, Salt Lake City, Utah, United States
  • Falzon, Isabelle Dorothy, University of Utah, Salt Lake City, Utah, United States
  • Somarathna, Maheshika Srimali, University of Alabama at Birmingham, Birmingham, Alabama, United States
  • Lee, Timmy C., University of Alabama at Birmingham, Birmingham, Alabama, United States
Background

Arteriovenous fistula (AVF) maturation is dependent on hemodynamics and remodeling of the vessel wall to increase the AVF flow rate and lumen area for dialysis. Sildenafil is a phosphodiesterase 5 inhibitor that promotes vasodilation and is used clinically to treat erectile dysfunction and pulmonary hypertension. Here we investigate the effect of sildenafil on lumen geometry and hemodynamics in rat AVFs.

Methods

Femoral AVFs were created in 12-16 week-old male Sprague-Dawley rats. Sildenafil was administered at 90 mg/kg in drinking water starting 14 days prior to AVF creation surgery (n=4). 21 days post creation, animals were subject to non-contrast MRI scans, and the MR images were used for reconstruction of the AVF lumen and computational fluid dynamic simulations of the AVF blood flow. Hemodynamic parameters (flow rate, wall shear stress (WSS), vorticity, and oscillatory shear index (OSI)) and geometrical analysis (cross sectional lumen area, anastomosis angle (AA), tortuosity, and nonplanarity angle (NA)) were calculated.

Results

Sildenafil significantly increased the lumen area and flow rate of both the venous and arterial limbs of the AVFs when compared to no-treatment controls (p<0.0001)(Fig. 1). WSS, vorticity and OSI of treated rats were also significantly higher than controls (p<0.0001)(Fig. 1). AA, tortuosity, and NA were not significantly different between the two groups. AA was approximately 40o in both groups.

Conclusion

The AA of our AVF rat model is similar to the AA in human radiocephalic AVFs in the literature. Sildenafil leads to significantly higher flow rate and larger lumen in both vein and artery than controls. Vorticity, WSS, and OSI are significantly higher in treated rats compared to control, which may be due to the increased flow rate. Sildenafil may have therapeutic potential to enhance AVF maturation by affecting the hemodynamics.

Funding

  • NIDDK Support