Reduction of vasoreactivity and thrombogenicity with laser-thermal angioplasty:  comparison with balloon angioplasty.
The vasoreactivity and thrombogenicity of laser-thermal angioplasty were examined and compared with those of balloon angioplasty in an atherosclerotic rabbit iliac artery.  Eight rabbits underwent laser-thermal angioplasty with a 1.7-mm hot-tip probe activated at 7 W with a probe temperature of 126 +/- 19 degrees C in one iliac artery.  The other iliac artery was treated with balloon angioplasty using a 2.0-mm balloon.  Angiographic luminal diameter increased from 0.19 +/- 0.15 to 1.54 +/- 0.35 mm by laser and from 0.29 +/- 0.22 to 1.84 +/- 0.20 mm by balloon (P less than 0.0001, respectively). However, it decreased to 1.34 +/- 0.42 for laser and 0.45 +/- 0.39 for balloon 60 minutes later (P less than 0.0001 vs immediately post). Both iliac arteries were visualized using angioscopy, which revealed thrombotic obstruction of 91% stenosis in the ballooned artery and 8% stenosis in the lased artery.  Vasoreactivity of treated vessels was also investigated.  Segments 3-mm long were obtained from either treated artery or control artery and examined for noradrenaline (10 -7 M) contraction.  The segments were then mounted isometrically with 1 g tension in Krebs-bicarbonate buffer. Developed tension was 0.13 +/- 0.21 g for laser thermal and 2.33 +/- 0.4 g for its control (P less than 0.0001), and 0.15 +/- 0.16 g for balloon dilatation and 2.12 +/- 0.43 g for its control (P less than 0.0001).  Neither acetylcholine at 10 -6 M or papaverine at 10 -4 M induced relaxation of treated segments.  Histology showed slight thermal injury at thermally-treated sites without thrombus, and intimal and medial dissection with thrombus formation at balloon dilated site.


CONCLUSIONS
(1) neither a laser-thermal recanalized or a balloon dilated obstructed artery is vasoreactive to constrictive or relaxant agents; and (2) laser-thermal angioplasty results in less thrombogenicity than balloon angioplasty under moderate probe temperature.
Tomaru
T
T
Second Department of Internal Medicine, University of Tokyo, Japan.
Uchida
Y
Y
Nakamura
F
F
Yanagisawa-Miwa
A
A
Kamijo
T
T
Sugimoto
T
T
D015906:Angioplasty, Balloon, Coronary / Q000379:methods*; D017222:Angioplasty, Balloon, Laser-Assisted / Q000009:adverse effects / Q000379:methods*; D017546:Angioscopy / Q000379:methods; D000818:Animals; D001161:Arteriosclerosis / Q000503:physiopathology / Q000628:therapy*; D003329:Coronary Vasospasm / Q000628:therapy*; D007083:Iliac Artery / Q000503:physiopathology; D008297:Male; D011817:Rabbits; D013927:Thrombosis / Q000503:physiopathology / Q000628:therapy*