Study of a new treatment using excimer laser for severe ischemic heart disease

探讨准分子激光在缺血性心脏病治疗中的应用前景。实验一研究了248 nm和308 nm准分子激光对猪心肌的烧蚀作用。组织学检查可观察到非常清晰的切痕，但由于热效应产生了小的邻近线。248 nm波长的热效应小于308 nm波长的热效应。此外，我们将准分子激光器耦合到光纤上，并测量了通过光纤传输的激光能量。在248nm波长处，纤维尖端被破坏。在第二个实验中，我们检测了准分子激光照射对血液的影响。在激光照射的细胞中不发生红细胞的溶解。然而，红细胞膜的损伤发生了，这可以通过进行性血红蛋白渗漏到血浆中来证明。在第三个实验中，我们对准分子激光在激光血管成形术中的可能应用进行了研究。准分子激光照射正常犬动脉后的愈合反应令人满意。采用准分子激光（XeCl: 308nm）对4条完全闭塞的杂种犬股动脉进行激光血管成形术。在2.5 ~ 6 m J/脉冲、20 ~ 30 pps、6000次注射的情况下，4条动脉均成功再通。另外，4只WHHL兔用于激光动脉内膜切除术。所有激光照射动脉的组织学检查显示良好的结果，没有热损伤的迹象，也没有血栓形成。结果提示准分子激光治疗缺血性心脏病的适用性。

We studied the possible application of excimer laser to ischemic heart disease. In the first experiment, we studied the ablative effects of excimer laser at the wavelengths of 248 nm and 308 nm on the pig myocardium. Very clear cuts could be observed by histological examination, but there was a small adjacent line produced by thermal effect. A wavelength of 248 nm had less thermal effect than a wavelength of 308 nm. In addition we coupled the excimer laser to an optical fiber and measured the laser energy transmitted through the fiber. At a wavelength of 248 nm , the fibertip was destroyed. In the second experiment, we examined effects of excimer laser irradiation on blood. The lysis of erythrocytes does not occur in the laser - exposed cells. However, the damage to erythrocyte membrane took place as it was evidenced by progressive hemoglobin leakage into plasma. In the third experiment, we carried out a study on the possible application of the excimer laser in laser angioplasty. The healing responses following irradiation of the excimer laser to normal canine artery was satisfactory. Laser angioplasty was performed in 4 totally occluded femoral arteries in mongrel dogs using the excimer laser (XeCl : 308nm). The arteries were successfully recanalized in all 4 arteries using 2.5 - 6 m J/pulse, 20 - 30 pps and 6000 shots. Additionally, 4 WHHL rabbits were used in laser endarterectomy.Histological examination of all laser - irradiated arteries revealed favorable results with no signs of the thermal injury and no thrombus formation. The results suggest the applicability of excimer laser to ischemic heart disease.