The purpose of this study was to determine the efficacy of intravascular
photodynamic therapy (
PDT) to prevent the development of intimal
hyperplasia. Anesthetized New Zealand white rabbits underwent placement of Fogarty balloon
catheters introduced via femoral artery cutdowns.
Catheters were passed retrograde 10 cm into the lower abdominal aorta, inflated six times, and withdrawn toward the inguinal ligament. Rabbits were then randomly assigned to one of the following groups: group 1,
drug with no light; group 2, no
drug with 240 joules of light; group 3,
drug plus 120 joules of light; or group 4,
drug plus 240 joules of light. Uninjured carotid arteries served as negative control vessels (N) and injured but non-
PDT-treated iliac artery segments served as positive controls (P).
Porfimer sodium (
photofrin) was administered in a dose of 5.0 mg/kg. Light was provided by a fiberoptic probe with a 1 cm cylindric diffuser attached to an
argon pumped
dye laser tuned to 630 nm to provide 1 W of
laser light for 120 or 240 seconds. One month after
PDT, rabbits were killed, perfusion fixed with
glutaraldehyde, and vessels removed and examined microscopically. Intimal thickness (mean +/- SD) was calculated and expressed as ratios of the intima/media at four equal positions. Results for N, P, and groups 1, 2, 3, and 4 were 0.02 +/- 0.00, 1.18 +/- 0.71, 0.76 +/- 0.33, 0.96 +/- 0.43, 0.14 +/- 0.22, and 0.36 +/- 0.16, respectively. Intimal thickness was significantly reduced in groups 3 and 4 when compared with P, group 1, and group 2 (p < 0.001, ANOVA). These results showed that intravascular
PDT was effective in reducing intimal
hyperplasia following arterial injury. This may be a practical method of delivering light for
PDT.