エキシマレーザー冠動脈形成術の特徴と臨床経験

抄録

To determine the efficacy of Excimer laser coronary angioplasty, experimental studies and clinical results were examined. Histological examination was perfermed using atheromatous lesions of Watanabe Hereditary Hyperlipidemic (WHHL) Rabbit. Catheter tip energy density was 35mJ/mm2 and excimer laser was irradiated in 1 and 3 seconds. Atheromatous plaques were vaporized 1.1+/-0.1mm in diameter and 0.6+/-0.1mm in depth with 1.6mm multifiber laser cathter. Minimal tissue thermal coagulation increased from 47+/-17μm to 66+/-10μm with debulking in 3seconds irradiation (p less than 0.05). However, heavy charring, severe thermal damage and vacuolization were not found. A little residual tissue was found in the bottom of the vaporized crater equivalent to guide wire lumen and laser dead space in catheter. This data suggests that residual tissue can cause intimal flap, thrombs and abrupt closure on long irradiation in the same position.
Operative transluminal laser coronary angioplasty (OTLCA) during aorto-coronary bypass surgery was performed in 4 cases (5 lesions). 4 lesions were successed and one lesion was not crossed by laser catheter because of hard calcification. Post operative angiographic examinations were all satisfied.
Percutaneous transluminal laser coronary angioplasty as an adjunct or alternative to conventional baloon angioplasty was also studied in 34 cases (36 lesions), not ideal for conventional baloon angioplasty. Procedural success was achieved in 34 lesions. Adjunctive balloon angioplasty was perfoermed on 25 lesions. There were no myocardial infarction and no death. This procedure is expected to solve the difficult lesions like type B and type C (AHA / ACC task force).