预置钬激光打孔心肌血管重建的实验研究

Prestabbed holes holmium laser channelling for myocardial revascularization in dogs

目的 探讨低能量钬激光在预置心肌孔道中产生的远期疗效。方法 实验对象为 13只健康杂种家犬 ,结扎其左冠状动脉第一对角支及回旋支 2～ 3分支 ,建立心肌缺血模型。3只犬用 6 0 W激光在缺血区直接打孔建立心肌孔道。 10只犬用 9号针头在缺血区预打孔后用 5 W激光沿上述孔道建立心肌孔道 ,每只犬缺血区平均 ( 13.0±2 .0 )个孔道。用同位素心肌显像技术 ,彩超监测实验不同阶段的心肌血流分布情况及心功能 ,用电镜和光镜检测心肌孔道周围组织学变化。结果 用 6 0 W打孔的 3只犬均在打孔时死于室颤。用 5 W打孔的 10只犬术中无 1只死亡。 5只犬于术后 1～ 2 d死亡。打孔后心功能较缺血时心功能明显增强 ( P<0 .0 0 1) ,但不能恢复到缺血前水平。 5只存活犬术后 2个月不同阶段的电镜和光镜观察结果均可见心肌孔道周围有新生血管形成 ,尤以成活 2 0 0 d以上者为著。结论 低能量预置心肌打孔是一种安全、有效的重建心肌血流和改善心功能的方法 ,其机制是诱导孔道周围心肌新生血管形成。

Objective To investigate the long term outcomes of myocardial revascularization by lowenergy laser induced transmyocardial channelling.Method Thirteen healthy hybrid dogs were used in the experiment.The ischemic models of the heart were established by ligation of the first diagonal artery of the LAD and 2 to 3 branches of the left circumflex artery.The myocardial channels in 3 dogs were made by direct using 60 watts laser.In the other 10 dogs the myocardial channels were made by using low laser energy (5 watts), guided by pre stabbed holes of an F9 needle (13 0±2 0).channels were made in the ischemic area in each dog.SPET was used to moniter the distribution and recovery of the myocardial blood flow.UCG was employed to detect the recovery of the cardiac function.The light and electron microscope were used to examine the histologic changes around the channels.Results All the 3 dogs using high energy laser died of ventricular fibrilation (VF) during the period of the procedure.No VF happened in the low energy group.5 dogs died 1～2 days after the procedures.The cardiac function recovered remarkably after the transmyocardial laser revascularization compared to the ischemic period (P<0.001),but not to the level of the pre ischemic period.In the 5 long time survival dogs,the blood flow and cardiac function recovered to the level of pre ischemic period two months later.Angiogenesis appeared in different time point of the experiment.This was especially obvious in dogs that survived over 200 days.Conclusion Low energy holmium laser transmyocardial revascularization is a safe and effective method to revascularize the ischemic myocardium and improve the cardiac function.