Jenkins R D, Sinclair I N, Anand R, Kalil A G, Schoen F J, Spears J R
Department of Radiology, Beth Israel Hospital, Boston.
Lasers Surg Med. 1988;8(1):30-9. doi: 10.1002/lsm.1900080108.
Dehiscence of portions of atheromatous plaques fractured during percutaneous transluminal coronary angioplasty may contribute to both abrupt reclosure and gradual restenosis. Laser balloon angioplasty has been shown to be effective in welding human plaque-arterial wall separations in vitro by heating tissues with a Nd:YAG laser during balloon inflation. To define the potentially useful therapeutic range of tissue temperature required to achieve thermal welds, 220 1-cm diameter discs of human postmortem atheromatous aortic tissue, the intimal plaque of which had been separated from the media, were exposed to 3-25 watts of Nd:YAG laser radiation delivered over a 12-mm2 nominal spot size for 20 seconds via a 400-micron core optical fiber. As measured with a thermistor, adventitial temperature reflected the temperature at the plaque-media junction to within 10 degrees C. The degree of tissue temperature elevation was related to delivered energy, while effective tissue penetration increased to maximum depth of 3 mm at the highest power density. Strength of tissue welds was defined as the force required to shear opposing layers of welded segments. Adventitial tissue temperatures below 80 degrees C were not associated with appreciable welds, while equilibrium temperatures between 95 degrees C and 140 degrees C were consistently associated with effective mean weld strengths, which increased linearly from 25 to 110 g, respectively. Temperatures greater than 150 degrees C were associated with rapid tissue dehydration and charring. These data suggest that the therapeutic range of tissue temperature that provides effective thermal fusion of intima-media separations is broad and that the depth and degree of thermal coagulation can be controlled by manipulation of laser energy delivery.
经皮腔内冠状动脉成形术期间破裂的动脉粥样硬化斑块部分的裂开可能导致急性再闭塞和逐渐的再狭窄。激光球囊血管成形术已被证明在体外通过在球囊膨胀期间用钕：钇铝石榴石激光加热组织来焊接人体斑块 - 动脉壁分离是有效的。为了确定实现热焊接所需的组织温度的潜在有用治疗范围，将220个直径为1厘米的人尸检动脉粥样硬化主动脉组织圆盘（其内膜斑块已与中膜分离）通过400微米芯光纤暴露于以12平方毫米标称光斑尺寸在20秒内传递的3 - 25瓦钕：钇铝石榴石激光辐射下。用热敏电阻测量时，外膜温度反映斑块 - 中膜交界处的温度，误差在10摄氏度以内。组织温度升高的程度与传递的能量有关，而在最高功率密度下有效组织穿透增加到最大深度3毫米。组织焊接强度定义为剪切焊接段相对层所需的力。低于80摄氏度的外膜组织温度与明显的焊接无关，而95摄氏度至140摄氏度之间的平衡温度始终与有效的平均焊接强度相关，平均焊接强度分别从25克线性增加到110克。高于150摄氏度的温度与组织快速脱水和炭化有关。这些数据表明，提供内膜 - 中膜分离有效热熔合的组织温度治疗范围很广，并且热凝固的深度和程度可以通过控制激光能量传递来控制。
