Photochemical Tissue Passivation Attenuates AV Fistula Intimal Hyperplasia

Objective:We hypothesized that decreasing vein compliance would protect the vein against stretch injury and reduce intimal hyperplasia (IH).Background:Although arteriovenous fistulas (AVFs) are the criterion standard for vascular access, their effectiveness is limited by poor patency with 40% to 60% failing due to IH. Venous stretch injury from exposure to arterial pressure induces IH. Photochemical tissue passivation (PTP) crosslinks adventitial collagen, decreasing vein compliance to resemble that of an artery.Methods:AVFs were created between the femoral artery and epigastric vein in rats (n = 29). PTP was performed on the vein immediately before vessel anastomosis. AVFs were harvested after four weeks. Venous diameter was measured at the initial procedure and harvest. Intimal area was measured for each segment. Ultrasound was performed at harvest to measure AVF flow.Results:Following AVF construction, venous diameter increased by 10%18% for PTP-treated vessels and 78%+/- 27% for controls (P0.0001). At one month, PTP reduced AVF dilation by 71% compared to control (69%+/- 29% vs 241%+/- 78%; P0.0001). Both juxta-anastomotic intimal area and total intimal area were reduced in PTP-treated vessels compared to control vessels. Specifically, intimal area was 0.024 +/- 0.018 and 0.095 +/- 0.089 mm(2) for PTP-treated juxta-anastomotic segments of AVF and control, respectively (P < 0.05). Mean total intimal area for PTP-treated and control AVF were 0.080 +/- 0.042 and 0.190 +/- 0.110 mm(2), respectively (P < 0.03). AVF flow was 46.9 +/- 35.3 and 19.1 +/- 10.1 mL/min for PTP-treated and control AVF, respectively (P < 0.109).Conclusions:These data demonstrate that PTP represents a promising therapy for the prevention of AVF IH, a process that might improve surgical outcomes for patients receiving hemodialysis.