We performed photodynamic therapy (PDT) using the Yttrium Aluminium Garnet-Optical Parametric Oscillated (YAG-OPO) laser in cases of atherosclerosis, and examined its efficacy in vivo. We also performed PDT using an Argon-dye (Ar-dye) laser with the same output, and compared the efficacies. Following balloon denudation injury of the thoracoabdominal aorta, rabbits were raised on a cholesterol diet for 16 weeks, producing atheroma in that region. At 24 h following the administration of Photofrin 5 mg/kg, PDT was performed, and animals were sacrificed at 1 day, 1 week, and 2 weeks following the procedure to examine its efficacy. This was compared with the efficacy of PDT using the Ar-dye laser. Following PDT using a YAG-OPO laser, an increase in the vessel lumen was seen due to reduction of the hypertrophic intima and media, without the appearance of inflammatory cells. This result was seen more strongly in PDT using the pulse wave YAG-OPO laser than with the continuous wave Ar-dye laser, affecting not just the intima but also the media. These data demonstrated that PDT can effectively regress atherosclerotic lesions. (Jpn Circ J 1999; 63: 288 -295)
arious interventional therapies are presently used in the treatment of ischemic heart disease. In clinical trials in the US, percutaneous transluminal laser coronary angioplasty (PTLCA) was performed on 3,000 patients and 3,592 lesions using excimer laser, with a reported success rate of 84%. 1 When this method is compared with percutaneous transluminal coronary angioplasty (PTCA) using a balloon, PTLCA can be performed on diffuse lesions in which PTCA is difficult, and it may be possible to use the laser to recanalize a chronic total occlusion, a lesion in which the passage of a guide wire would be very difficult. In addition, PTCA is contraindicated in ostial stenosis, and PTLCA is considered the first choice in closed chest treatment. In PTLCA, however, unexpected coronary perforation occurs in between 1.2 to 2.4% of cases, 1-4 a rate which is obviously higher than for PTCA. As avoidance of coronary perforation is the paramount consideration in PTLCA, the requirement is for an appropriate guidance system to show the condition of the hypertrophic intima and the degree of ablation in real time, so that the atheroma alone is selectively ablated and the tunica media not irradiated.At present, evaluation of coronary arteriosclerotic lesions is made using angioscopy and intravascular ultrasound, neither of which can be inserted into the coronary artery at the same time as the laser irradiation system and so cannot be the appropriate guidance system. Fluorescence spectrum analysis is a method by which the fluorescence induced by irradiation at specific wavelengths of an arteriosclerotic lesion is examined in detail to make the diagno-
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.