PhotoPoint photodynamic therapy inhibits intimal hyperplasia in arteriovenous access grafts.

Abstract Purpose: To evaluate the ability of PhotoPoint photodynamic therapy (PDT) to suppress venous anastomotic intimal hyperplasia (IH) in a canine prosthetic arteriovenous graft (AVG) model. Methods and materials: Bilateral femoral AVGs were placed in 12 mongrel dogs. PhotoPoint PDT was optimized by treating venous anastomoses with a fixed dose of photosensitizer (MV6401) followed by varying light doses. Veins were evaluated at 3 days for cell depletion. Other venous anastomoses received the optimal PhotoPoint PDT dose following graft placement and were harvested 1 month later. Histological sections of venous anastomoses were analyzed for intimal thickness, fibrosis, inflammation, necrosis and thrombosis. Results: PhotoPoint PDT resulted in a significant reduction of venous anastomotic intimal thickness. In addition, PhotoPoint PDT tended to reduce the development of fibrosis. All veins were patent at harvest, and there was no evidence of PhotoPoint PDT-related pathologies. Conclusions: PhotoPoint PDT significantly inhibited the development of venous anastomotic IH. These results suggest that PhotoPoint PDT is feasible and may increase patency rates of synthetic hemodialysis AVGs in the clinic.