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Photodynamic therapy for atherosclerotic stenoses in Yucatan miniswine
Y N Hsiang1, M T Crespo, L S Machan
1Department of Surgery, University of British Columbia, Vancouver.
Objective:
To determine the feasibility of treating atherosclerotic stenoses with photodynamic therapy (PDT).
Design:
A prospective study with a 4-week follow-up.
Subjects:
Twelve Yucatan miniswine, weighing between 25 and 35 kg.
Interventions:
Aortoiliac atherosclerosis was created by a combination of balloon endothelial injury and dietary supplementation with 2% cholesterol and 15% lard for 7 weeks. Then the miniswine were given a porphyrin-type photosensitizer (Photofrin), 2.5 mg/kg intravenously, and treated with 630 nm light through an intravascular, cylindrical, diffusing fibreoptic probe, which was coupled to an argon-pumped dye laser to supply 120 J of laser energy.
Main Outcome Measures:
Differences in luminal narrowing before and after PDT.
Results:
Seven miniswine had an increase in luminal diameter, but five had no increase. Microscopy demonstrated a broad range of features in treated vessels, including areas with re-endothelialization and regions of platelet and blood cell adherence with absent or abnormal endothelium.
Conclusion:
Although this study demonstrated resolution in stenoses for some miniswine, questions concerning light dosimetry, mechanism of action and long-term effects remain to be determined.