Photoremodeling of Arterial Wall Reduces Restenosis After Balloon Angioplasty in an Atherosclerotic Rabbit Model

Objectives. This study evaluated the long-term impact of endoluminal low power red laser light (LPRLL) on restenosis in an atherosclerotic rabbit model. Background. Despite widespread application of balloon angioplasty for treatment of coronary artery disease, restenosis limits its clinical benefits. Restenosis is complex process and may be partly attributed to the inability of the vascular endothelium to regenerate and cover the denuded are at the site of arterial injury. We previously demonstrated that LPRLL stimulates endothelial cell proliferation in vitro and contributes to rapid endothelial regeneration after balloon injury in nonatherosclerotic rabbits. Methods. Rabbit abdominal aortas (n = 12) were treated in separate zones with balloon dilation and balloon dilation plus laser illumination. Endoluminal laser therapy was performed using laser-balloon catheter delivering single dose of 10 mW for 3 min from helium-neon laser (632 nm). Angiography was performed before and after treatment and was repeated 8 weeks before harvesting the aortas. Results. Quantitative angiographic analysis demonstrated no differences in the minimal lumen diameter (MLD) between the two zones before treatment; an increase in the MLD in both zones after balloon angioplasty and significant versus slight reduction of the MLD in the balloon treatment versus balloon plus laser zones at 8 weeks. Histologic examination showed very high level of myointimal hyperplasi in the balloon treatment zones but minimal level in the LPRLL-treated zones. Morphometric analysis revealed statistically significant difference in the lumen area, intimal are and intima/medi ratio between the balloon versus balloon plus laser treatment sites. Conclusions. Our experimental dat indicate that endoluminal irradiation with LPRLL prevents restenosis after balloon angioplasty in an atherosclerotic rabbit model.