Selective pulsed dye laser thrombus ablation : Can contrast media replace fiberoptics in pulsed dye laser delivery system?

BACKGROUND: The absorption coefficient of the arterial thrombus is 7~10 fold greater than that of arterial wall for the wave lengths of 480~510nm. This fact suggest that selective laser thrombus ablation could be possible without ablation of surrounding vessel wall in this wavelengths. METHODS: Pulsed dye laser(488nm, 2.2micros, 10Hz) thrombus ablation was investigated in viro. Ablation threshods of whole blood clot and normal aortic tissue were measured using a 1.5mm multifiber laser catheter(14x150microm). Whole blood clot samples were lasered to determine the ablation efficiency. The operative fluence was 80mJ/mm2. The transmission efficiencies of 488nm wave length through various transmission media(including contrast media of saline solution) were observed using a upsilon Fr arterial sheath filled with transmission medium. RESULTS: The ablation threshold for fresh whole blood clot in saline solution was 36.5+/-2.4mJ/mm2(9.0+/-0.6mJ/pulse) as compared with that for normal human aortic tissue which was over 405mJ/mm2(>100mJ/pulse)(p<0.05). Pulsed dye laser ablated whole blood clot with the efficiency at 0.026+/-0.009gm/J. The role of thrombus ablation was 0.154+/-0.056gm/min. This experiment also revealed that cotrast media(Ultravist(R) 370, Schering, France) allows light tramission of 488nm wave length at relatively high efficiency. CONCLUSIONS: These facts suggested that selective pulsed dye laser ablation of fresh intravascular thrombi can be obtained at relatively low energy fluence without damaging the surrounding vascular tissue. A new pulse dye laser delivery system such as catheter system or native coronary artery filled with contrast media, which has large area of frontfiring face, may facilitate a safe and effective thrombus ablation.

The research of power intelligent control of ultrasonic thrombus melting based on BP Neural Network / 医疗卫生装备

In this paper, intelligent control of ultrasonic power during the process of thrombus ablation is realized through the combination of BP Neural Network and the expert system of ultrasonic thrombus ablation. One proper real-time power can be output correspondingly to different treatment circumstance according to expert ruler during the process of treatment.

CLINICAL EXPERIENCE OF TREATING ARTERIAL AND VENOUS OCCLUSIVE DISEASES BY ULTRASONIC THROMBUS ABLATION TECHNIQUE / 解放军医学杂志

To look for a novel micro traumatic and highly effective method to treat arterial and venous occlusive diseases, ultrasonic thrombus ablation technique was applied in 7 cases of arterio sclerosis obstruction (ASO) of the lower limbs and 15 cases of deep vein thrombosis (DVT) of the lower limbs. The indications, precautions during the operation, and postoperative treatment were summarized. Recanalization of the vessels was achieved in all the patients without perforation. Angiographic examination showed that the stricture of arteries of the patients with ASO was reduced from (93?12)% to (12?6)%, and their symptoms were remarkably ameliorated. In 15 DVT patient, venous occlusion was reduced from 100% to (8?2)% on angiogram, and edema of their limbs subsided. We consider ultrasonic thrombus ablation is an effective, safe, and minimally traumatic treatment modality for arterial and venous occlusive diseases.