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

我们研究了准分子激光在缺血性心脏病中的可能应用。在第一个实验中，我们研究了波长为248 nm和308 nm的准分子激光对猪心肌的消融作用。组织学检查可观察到非常清晰的切口，但有一个小的相邻线产生的热效应。248 nm的波长具有比308 nm的波长小的热效应。此外，我们还将准分子激光器耦合到光纤中，并测量了通过光纤传输的激光能量。在248 nm的波长下，光纤尖端被破坏。在第二个实验中，我们研究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溶解。然而，红细胞膜发生损伤，因为血红蛋白逐渐渗漏到血浆中。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。用准分子激光照射正常犬动脉，其愈合反应令人满意。用准分子激光（XeCl：308 nm）对4条杂种犬完全闭塞的股动脉进行了激光血管成形术。使用2.5 - 6 m J/脉冲，20 - 30 pps和6000次注射，所有4条动脉均成功再通。此外，对4只WHHL兔进行了激光动脉内膜切除术，所有激光照射动脉的组织学检查均显示良好的结果，没有热损伤迹象，也没有血栓形成。结果表明，准分子激光治疗缺血性心脏病是可行的。

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.