Optimal dosing of intravascular low-power red laser light as an adjunct tocoronary stent porcine coronary implantation: Insights from a stent model

Background: It is believed that restenosis following coronary interventions is the result of endothelial denudation that leads to thrombus formation, vascular remodeling, and smooth muscle cell proliferation. Low-power red la ser light (LPRLL) Irradiation enhances endothelial cell growth in vitro and in vivo, and reduces restenosis in animal models. The present study invest igated the optimal dose of intravascular LPRLL therapy in the prevention of in-stent stenosis in a porcine coronary stent model. Methods and Results: Selected right coronary artery segments were pretreated with a LPRLL balloo n, delivering a dose of 0 mW during 1 min (group 1, n = 10), 50 mW during I min (group II, n = 10), or 100 mW during 1 min (group III, n = 10) before stenting. Quantitative coronary analysis of the stented vessel was performe d before stenting, immediately after stenting, and at 6 weeks follow-up. Th e pigs were sacrificed, and histologic and morphometric analyses were condu cted. At 6 weeks, minimal luminal stent diameter was significantly narrower in the control group compared to the 50-mW dose group (p < 0.05). These re sults were confirmed by morphometric analysis. Neointimal area was also sig nificantly decreased in the 50-mW dose group. Conclusions: Intravascular LP RLL contributes to reduction of angiographic in-stent restenosis and neoint imal hyperplasia in this animal model. The optimal dose using the LPRLL bal loon system seems to be approximately 5 mW delivered during 1 min.