高频电刺激指导肾动脉射频消融的实验研究

目的:用电刺激的方法指导肾脏去神经术(renal denervation,RDN)中射频消融靶点的选择,同时比较电刺激与射频消融时血压变化的异同。方法:成年健康昆明犬6只,行肾动脉造影排除肾动脉畸形后,每侧肾动脉从远段开始,由远及近选择数个位点进行电刺激并消融。连续记录术中血压的变化,术后通过软件分析血压的变化情况。采用常规HE和Masson染色观察肾动脉壁结构及其周围组织;采用酪氨酸羟化酶(tyrosine hydroxylase,TH)免疫组化染色观察消融后肾动脉去神经效果。结果:本实验中刺激/消融位点共计50个,其中对电刺激有反应的位点占34%,无反应位点占66%。对有反应位点进行120 s电刺激时,其收缩压按每20 s分段与基线血压相比分别变化(0.34±3.38)、(0.41±3.04)、(10.47±5.73)、(13.27±3.63)、(10.17±1.87)和(0.78±1.87)mm Hg;将120 s连续消融时的收缩压数据同样按每20 s与基线血压相比,变化分别为(0.88±3.44)、(-1.64±3.47)、(13.17±3.12)、(12.82±3.21)、(9.50±2.68)和(-6.09±2.21)mm Hg。无反应位点进行电刺激和射频消融时均无明显血压升高。组织病理学检查显示,有反应位点肾动脉神经面积为(0.51±0.28)mm~2,无反应位点处为(0.09±0.06)mm~2,差异有统计学显著性(P0.01);免疫组化染色表明消融部位神经TH的表达显著低于未消融部位(P0.01)。结论:高频电刺激可以标测肾交感神经,且电刺激指导下的射频消融能对肾动脉交感神经造成有效损伤。

Experimental study of renal radiofrequency ablation guided by high-frequency electrical stimulation

AIM: To evaluate the guiding effect of high-frequency stimulation (HFS) on renal denervation (RDN), and to compare the similarities and differences of blood pressure changes at the time of electrical stimulation and radiofrequency ablation. METHODS: A total of 6 Kunming dogs were included in this study. Renal artery abnormalities were excluded by angiography. High-frequency stimulation and radiofrequency ablation were performed at the same sites from distal to proximal segments of the renal artery. Invasive blood pressure (BP) was recorded during the whole procedure. The change of the blood pressure was analyzed. HE and Masson staining was adopted to detect the structural changes in the wall of the renal artery and surrounding tissues. The immumohistochemical staining for tyrosine hydroxylase (TH) was used to observe the renal nerve damage after ablation. RESULTS: Electrical stimulation and radiofrequency ablation were delivered in a total of 50 sites. The BP increasing response was induced at 34% sites (n=17), while the rest sites (66%, n=33) had no response. Compared with the baseline, HFS caused the increases in systolic BP of (0.34±3.38), (0.41±3.04), (10.47±5.73), (13.27±3.63), (10.17±1.87) and (0.78±1.87) mmHg in 6 serial 20 s time segments during 120 s of HFS at positive BP response sites. Similarly, the increases in systolic BP by (-0.88±3.44), (-1.64±3.47), (13.17±3.12), (12.82±3.21), (9.50±2.68) and (-6.09±2.21) mmHg were observed during 120 s of ablation procedure at the same sites in 6 serial 20 s time segments. At non-responding sites, HFS and ablation failed to cause a significant increase in systolic BP. The mean area of nerves in the response sites was (0.51±0.28) mm², whereas that in non-response sites was (0.09±0.06) mm² (P<0.01). The average absorbance values of TH in renal nerves at ablation and non-ablation sites were 0.031±0.015 and 0.085±0.018 (P<0.01), respectively. CONCLUSION: Renal sympathetic nerves can be effectively mapped by HFS. Radiofrequency ablation guided by HFS is valid to injure sympathetic nerves around renal artery.