The CO2 laser as an intraluminal repair tool

Neointimal hyperplasia following argon ion laser carotid endarterectomy: with and without endothelial cell seeding

BACKGROUND AND OBJECTIVE

This study compares the development of neointimal hyperplasia following conventional and argon ion laser carotid endarterectomy and assesses the potential advantage of endothelial cell seeding.

STUDY DESIGN/MATERIALS AND METHODS

Eight dogs underwent conventional endarterectomy in one carotid artery and an argon ion laser endarterectomy in the other. After 42 days, these arteries were harvested and the intimal thickness were compared. Six additional dogs underwent bilateral argon ion laser carotid endarterectomy with endothelial cell seeding on the one side only. These arteries were harvested after 65 days and their mean intimal thickness were compared.

RESULTS

At 42 days, the mean intimal thickness in the conventional endarterectomy group was 0.070 +/- 0.007 mm; in the argon ion laser endarterectomy group it was 0.058 +/- 0.001 mm (P = 0.76, NS). At 65 days, the mean intimal thickness in the group without endothelial cell seeding was 0.125 +/- 0.003 mm vs. 0.061 +/- 0.001 mm on the seeded side (P = 0.043).

CONCLUSION

Argon ion laser carotid endarterectomy results in no more neointimal hyperplasia than conventional endarterectomy. The neointimal hyperplasia is reduced by endothelial cell seeding.

Initial results of endothelial cell seeding following argon laser carotid endarterectomy

This study evaluates the initial results of endothelial cell (EC) seeding following argon laser carotid endarterectomy. Venous endothelial cells were harvested from 12 dogs and cultured. A laser endarterectomy was performed on both carotids of each dog. One side was seeded with endothelial cells. Six dogs had both carotids harvested 1 hour after restoring blood flow. The others were harvested in 24 hours. The percentage of lumen covered with EC was evaluated by scanning electron microscopy. At 1 hour, the seeded arteries demonstrated 35 +/- 3 percent EC coverage, whereas the unseeded arteries had no EC coverage (P = 0.0002). At 24 hours, the seeded arteries had 58 +/- 15 percent EC coverage, whereas the unseeded arteries had no coverage (P = 0.01). Significant gross thrombus developed only in unseeded arteries (P = 0.047), two of which were occluded at 24 hours. EC seeding is beneficial following argon laser carotid endarterectomy resulting in improved patency and less surface thrombogenicity.

Application systems for intracorporeal laser-induced shockwave lithotripsy using the Nd:YAG Q-switched laser

For laser-induced shockwave lithotripsy, the electromagnetic energy of a laser light pulse is converted intracorporeally into the acoustic energy of a shockwave. The lithotriptor is based on a specially developed, Q-switched Nd:YAG laser whose high power light pulses (70 mJ, 25 nsec) are coupled into a flexible quartz fiber with a core diameter of 600 mum. Using focusing elements, energy densities higher than 6 x 10 5 J m -2 can be achieved, resulting in an optical breakdown in water followed by a shockwave. As a result of different absorption mechanisms, the breakdown threshold can be decreased by placing a metallic target into the laser beam. The different shockwave formations of such optomechanical transducers have been measured. First clinical applications have been performed.