Efficacy of carbon monoxide laser in selectively intimal thermal welding--implications for laser balloon angioplasty.
Excessive vascular damage causes excessive vascular repair, which results in restenosis. To limit the thickness of the coagulation layer in laser balloon angioplasty, we used a carbon monoxide (CO) laser, which has high tissue absorption, as a therapy laser source instead of a Nd: YAG laser. To investigate the benefit of short-penetration CO laser light to vascular tissue, excised human abdominal aorta was irradiated with a CO laser through a 30 microns polyethylene membrane. The temperature of the vascular tissue was continuously monitored during irradiation. CO laser irradiation of 20 W/cm2 was performed in either a continuous mode or an intermittent mode with various duty ratios (exposure/interval duration). With a total fluence of 200 J/cm2, the adventitial temperature decreased as the duty ratio was reduced. The adventitial temperature at a duty ratio of 1:2 was 43 degrees C. Microscopic examination of aorta which had been intermittently irradiated duty ratio of 1:2 showed thermal coagulation localized within the intima and a flattened intimal surface. These results suggest that intermittent laser irradiation with a CO laser can be used to limit the depth of thermal coagulation, and can selectively weld the intima without excessive thermal damage. Laser balloon angioplasty using a CO laser may help to prevent restenosis.
Miyamoto
A
A
First Department of Internal Medicine, National Defense Medical College, Saitama, Japan.
Sakurada
M
M
Arai
T
T
Mizuno
K
K
Kurita
A
A
Nakamura
H
H
Kikuchi
M
M
D017222:Angioplasty, Balloon, Laser-Assisted / Q000379:methods; D001012:Aorta, Abdominal / Q000473:pathology / Q000528:radiation effects / Q000601:surgery*; D002248:Carbon Monoxide; D006801:Humans; D017075:Laser Coagulation / Q000379:methods; D017539:Tunica Intima / Q000473:pathology / Q000528:radiation effects / Q000601:surgery*
D002248:Carbon Monoxide