Peripheral Vascular Surgery Society

#5. LOCAL APPLICATION OF b-PARTICLE RADIATION TO REDUCE VENOUS INTIMAL HYPERPLASIA.

Victor Z. Erzurum, MD, Urs Hafeli, PhD, Mark Hirko, MD, and Jeffrey R. Rubin, MD

Western Reserve Care System, Youngstown, OH

Introduction: The long term patency of arteriovenous fistulas (AVF) created for hemodialysis is limited especially when prosthetic implants such as polytetrafluoroethylene (PTFE) are used. Since intimal hyperplasia (IH) at the venous anastomosis is the most common cause of AVF failure, a therapeutic technique to safely diminish this hyperplastic response would be valuable to patients on dialysis. Recently, pure b-emitting stents have been shown to be effective in decreasing IH in the coronaries after angioplasty. The benefit of b-particle radiation is that 99% of the dose is absorbed within 5mm of the source, thus minimizing radiation toxicity. This study was designed to assess the ability of a new b-emitting external foil to inhibit IH at the venous anastomosis in PTFE AVFs in a canine model.

Method: Bilateral PTFE bridge graft AVFs were placed from the femoral artery to vein in adult mongrel canines. A b-emitting metallic foil coated with Rhenium-188 was placed around the venous anastomotic site of one AVF in each animal. Twelve weeks after AVF implantation each animal was sacrificed and samples of each anastomosis analyzed.

Results: A total of eight venous anastomoses were analyzed for thrombus free surface area, and histologic evaluation including morphometric measurements of the intima and media. Preliminary results indicate a trend toward attenuated IH in the radiated anastomoses at twelve weeks time. However, significant foreign body response was noted external to the vein and anastomosis on the implant side.

Conclusion: This study suggests that venous IH can be attenuated in canine PTFE AVFs with the use of an external b-emitting foil. Further larger studies to determine the ideal dosimetry and implant material to maximize vein contact and minimize foreign body response are necessary. This technology could result in a safe and effective way to improve patency in AVFs.

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Last updated January 1,2000