Estvold Soren K, Mordini Frederico, Zhou Yifu, Yu Zu X, Sachdev Vandana, Arai Andrew, Horvath Keith A
National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA.
Lasers Surg Med. 2010 Dec;42(10):746-51. doi: 10.1002/lsm.21012.
Transmyocardial laser revascularization (TMR) is currently clinically performed with either a CO(2) or Ho:YAG laser for the treatment of severe angina. While both lasers provide symptomatic relief, there are significant differences in the laser-tissue interactions specific to each device that may impact their ability to enhance the perfusion of myocardium and thereby improve contractile function of the ischemic heart.
A porcine model of chronic myocardial ischemia was employed. After collecting baseline functional data with cine magnetic resonance imaging (MRI) and dobutamine stress echo (DSE), 14 animals underwent TMR with either a CO(2) or Ho:YAG laser. Transmural channels were created with each laser in a distribution of 1/cm(2) in the ischemic zone. Six weeks post-treatment repeat MRI as well as DSE were obtained after which the animals were sacrificed. Histology was preformed to characterize the laser-tissue interaction.
CO(2) TMR led to improvement in wall thickening in the ischemic area as seen with cine MRI (40.3% vs. baseline, P < 0.05) and DSE (20.2% increase vs. baseline, P < 0.05). Ho:YAG treated animals had no improvement in wall thickening by MRI (-11.6% vs. baseline, P = .67) and DSE (-16.7% vs. baseline, P = 0.08). Correlative semi-quantitative histology revealed a significantly higher fibrosis index in Ho:YAG treated myocardium versus CO(2) (1.81 vs. 0.083, P < 0.05).
In a side-by-side comparison CO(2) TMR resulted in improved function of ischemic myocardium as assessed by MRI and echocardiography. Ho:YAG TMR led to no improvement in regional function likely due to concomitant increase in fibrosis in the lasered area.
经皮心肌激光血运重建术（TMR）目前在临床上使用二氧化碳或钬：钇铝石榴石激光来治疗严重心绞痛。虽然两种激光都能缓解症状，但每种设备特定的激光与组织相互作用存在显著差异，这可能会影响它们增强心肌灌注从而改善缺血性心脏收缩功能的能力。
采用慢性心肌缺血的猪模型。在用电影磁共振成像（MRI）和多巴酚丁胺负荷超声心动图（DSE）收集基线功能数据后，14只动物接受了二氧化碳或钬：钇铝石榴石激光的TMR治疗。在缺血区用每种激光以每平方厘米1条的分布创建透壁通道。治疗后6周，再次进行MRI和DSE检查，之后处死动物。进行组织学检查以表征激光与组织的相互作用。
如电影MRI所示，二氧化碳TMR导致缺血区域的室壁增厚改善（40.3%对基线，P＜0.05），DSE显示也有改善（较基线增加20.2%，P＜0.05）。钬：钇铝石榴石激光治疗的动物通过MRI测量的室壁增厚没有改善（-11.6%对基线，P = 0.67），DSE测量结果也是如此（-16.7%对基线，P = 0.08）。相关的半定量组织学显示，钬：钇铝石榴石激光治疗的心肌纤维化指数显著高于二氧化碳激光治疗的心肌（1.81对0.083，P＜0.05）。
在一项并列比较中，通过MRI和超声心动图评估，二氧化碳TMR可改善缺血心肌的功能。钬：钇铝石榴石激光TMR未能改善局部功能，可能是由于激光照射区域的纤维化同时增加所致。
