agar and Thrombosis

The usefulness and safety of water jet angioplasty was studied in vitro, using agar phantom and autopsied aorta, and in vivo in acute and chronic arterial occlusions in mongrel dogs. At an injection rate of 1.0 ml/s, the water jet produced erosion of the agar surface when the distance between the catheter and the agar was 1 mm. With an injection rate of 1.5 ml/s, erosion was produced at a distance of 15 mm from the catheter tip. When the water jet was directed at an arterial wall, intimal ablation and ruptured elastic fibers were found histopathologically. A smaller angle between the vascular wall and the catheter was associated with less vascular damage. In vivo, water jet angioplasty was effective against acute obstructions, but not against chronic obstructions. These results suggest that water jet angioplasty may be effective against arterial obstruction due to acute thrombus.

Topics: Agar; Angioplasty, Balloon; Animals; Aorta; Disease Models, Animal; Dogs; Equipment Design; Evaluation Studies as Topic; Femoral Artery; Humans; In Vitro Techniques; Models, Structural; Polyethylenes; Radiography, Interventional; Thrombosis; Water

Discs of agar gel mixed with ink were used to study ablation effects with an argon laser as a light source. Varying amounts of ink were added resulting in a variation of the attenuation coefficient between 0.45 and 6.3 mm-1. For laser beam irradiation horizontally incident on a vertical sample, the average velocity of ablation was found to be approximately constant for thicknesses up to 1.7 mm. When the laser beam was directed vertically on a sample held horizontally, the vaporized debris present in the beam attenuated the incident laser energy to such a degree that the average ablation velocity decreased by a factor of approximately five. Horizontal beam experiments for various attenuation coefficients showed that an attenuation coefficient of about 1.7 mm-1 is optimal for fast penetration of discs thicker than 4 mm. Thus, based upon the optical properties of a given tissue, there may exist an optimum laser wavelength to maximise ablation velocity.

Topics: Agar; Arteriosclerosis; Humans; Laser Therapy; Models, Biological; Thrombosis

Topics: Agar; Animals; Carbamates; Endotoxins; Epinephrine; Escherichia coli; Hemorrhage; Necrosis; Pyridines; Rabbits; Thrombosis

Topics: Agar; Animals; Carrageenan; Dextrans; Drug Synergism; Epinephrine; Hemorrhage; Hindlimb; Iron; Ischemia; Lead; Scandium; Serotonin; Thorium; Thrombosis; Tourniquets

Topics: Agar; Animals; Epinephrine; Female; Hemorrhage; Mast Cells; Purpura; Rats; Thrombosis

Topics: Agar; Animals; Common Bile Duct; Duodenal Diseases; Female; Hemorrhage; Jejunum; Necrosis; Rats; Thrombosis

Topics: Agar; Animals; Carrageenan; Cold Temperature; Epinephrine; Hemorrhagic Disorders; Indium; Rats; Tannins; Thorium Dioxide; Thrombosis