title: Photochemical Tissue Passivation Attenuates AV Fistula Intimal Hyperplasia.
abstract: 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 (P ≤ 0.0001). At one month, PTP reduced AVF dilation by 71% compared to control (69% ± 29% vs 241% ± 78%; P ≤ 0.0001). 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 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, 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.
authors.affiliation: Department of Surgery, Division of Plastic and Reconstructive Surgery, Harvard Medical School, Massachusetts General Hospital, Boston, MA.
authors.forename: Robert N
authors.initials: RN
authors.lastname: Goldstone
authors.affiliation: Department of Surgery, Division of Plastic and Reconstructive Surgery, Harvard Medical School, Massachusetts General Hospital, Boston, MA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: McCormack
authors.affiliation: Department of Surgery, Division of Plastic and Reconstructive Surgery, Harvard Medical School, Massachusetts General Hospital, Boston, MA.
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Goldstein
authors.affiliation: Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, Boston, MA.
authors.forename: Srivalleesha
authors.initials: S
authors.lastname: Mallidi
authors.affiliation: Department of Surgery, Division of Plastic and Reconstructive Surgery, Harvard Medical School, Massachusetts General Hospital, Boston, MA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Randolph
authors.affiliation: Department of Surgery, Division of Vascular and Endovascular Surgery, Harvard Medical School, Massachusetts General Hospital, Boston, MA.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Watkins
authors.affiliation: Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, Boston, MA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Redmond
authors.affiliation: Department of Surgery, Division of Plastic and Reconstructive Surgery, Harvard Medical School, Massachusetts General Hospital, Boston, MA.
authors.forename: William G
authors.initials: WG
authors.lastname: Austen
mesh_terms: D000818:Animals; D001164:Arteriovenous Fistula / Q000175:diagnosis / Q000188:drug therapy*; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects*; D004195:Disease Models, Animal; D006965:Hyperplasia; D008297:Male; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017539:Tunica Intima / Q000473:pathology*
chemical_list: D017319:Photosensitizing Agents