机械性TMR与激光TMR的形态学对照观察

Contrastive observation of histomorphology on the channels after TMR by CO_2 laser and by machine drilling

目的 :从形态学角度观察机械性TMR与激光TMR对心肌管道热损伤、血管生成及纤维化的影响 ,探讨最佳的TMR方法。方法 :采用高速空心钻头和CO2 激光在家兔左室壁进行打孔 ,形成透室壁性心肌管道。动物于术后不同时间处死 ,利用组织切片染色法 ,分别观察机械性和激光心肌管道内形态结构及其变化。结果 :机械钻孔形成的心肌管道不存在任何热损伤的迹象 ,而激光形成的心肌管道存在着严重的热损伤 ;数周后机械管道内新生血管的数量和密度明显高于激光管道 ,P <0 .0 1;6～ 8周后 ,机械管道残迹的纤维化直径明显小于激光管道 ,P <0 .0 0 0 1。结论 :①机械性TMR和激光TMR在心肌管道的热损伤、血管生成及纤维化方面均存在着非常显著或极显著性差异 ;②应用机械钻孔的方式进行TMR明显优于激光心肌打孔。

Objective:To observe the effects of thermal injury,angiogenesis and fibrosis on the channels after transmyocardial revasculariaztion (TMR) by CO 2 laser and by machine drilling from the view of histomorphology,so that the better method of TMR would be selected.Methods:Under direct vision,transmyocardial channels were made by CO 2 laser and by machine drilling in vivo on the left ventricular wall of 54 rabbits.The average diameters of both channels were similar (laser,0.8～1.0 mm,drilling 1.0～1.2 mm).The animals were sacrificed at intervals of 1,2,4 and 6～8 weeks after TMR.The effects of thermal injury,angiogenesis and fibrosis were observed under microscope.Results:There was severe thermal injury around the channes made by CO 2 laser.The thickness of thermal injury was 0.5～1.0 mm.There wasn't any indication of thermal injury on the wall of the channels made by machine drilling.After several weeks,histology showed all channel remnants composed of granulation tissue,new vessels (NV) and fibrosis.Histological and histochemical analysis confirmed the presence of endothelial cells within NV.The density analysis of the NV within the channel remnants revealed significant difference (after 2 weeks,7.23±0.48NV per 10×4 field in laser versus 8.41±0.59 in drilling, P <0.01;after 6～8 weeks,2.22±0.33 NV per 10×4 field in laser versus 3.31±0.57 in drilling, P <0.01);The diameter analysis of fibrosis in both channels demonstrated a high significant difference (laser, 1.73± 0.05 mm,drilling, 0.67±0.03 mm. P <0.001).Conclusions:This study shows that there is significant difference between CO 2 TMR and machine drillling TMR in their effects on thermal injury,angiogensesis and fibrosis,therefore the method of machine drilling TMR is better than CO 2 TMR on the view of histomorphology.