JACC：我国学者发明无创去肾交感神经术

　　体外高强度聚焦超声引导下的无创去肾交感神经术首次在狗模型中获得成功

　　在顽固性高血压治疗领域，经导管射频消融去肾交感神经术（RSD）可以说是划时代之创举，Symplicity HTN 研究证实了经导管射频消融RSD的安全性和有效性。

　　近日，我国重庆医科大学附属第二医院心内科黄晶教授等发表文章，宣布首次在狗模型上成功完成体外高强度聚焦超声（HIFU）引导下的无创RSD。研究者认为，无创HIFU 将成为重要的RSD 策略。（J Am Coll Cardiol. 2013 年3 月27 日在线版）

　　研究者指出，经导管射频消融RSD 可导致血管壁损伤和血液动力学不稳定。为了减少对血管壁的损伤，大家正在积极尝试各种无创新方法。HIFU 能通过在体外集中供给能量，起到无创切除组织尤其深部实体组织的效果，常用来治疗子宫、肾脏和肝脏肿瘤。受此启发，研究者尝试在狗模型上采用体外HIFU 技术开展无创RSD。

　　在该研究中，23 只血压正常的狗被随机分入消融术组和假手术组，在消融术前及术后第6 d 和第28 d 进行血压、血浆去甲肾上腺素水平和肾功能检测。消融术组在体外HIFU 技术支持下，对狗的双侧肾神经进行消融治疗（图1）。结果显示，两组动物接受治疗后生存率为100%。与基线水平及假手术组相比，消融术组的血压和血浆去甲肾上腺素水平均明显降低：术后第28 d 时，消融术组的血压较基线降低15.9/13.6mm Hg，血浆去甲肾上腺素水平降低55.4%，而假手术组无明显变化。术后第6 d 时，消融术组狗的肾动脉外膜周围发现有消融病变。术后第28 d 时，肾神经组织学检查显示：肾交感神经的神经纤维断裂、施万细胞和神经元坏死以及有明显的去神经支配。研究期间，未出现手术相关并发症。

　　研究者观点

　　采用获得批准用于临床的HIFU 技术，我们成功在每只试验动物上完成了无创RSD 消融术。与经导管RSD 消融术不同的是，HIFU 指导下的RSD 技术不受肾动脉解剖结构的影响。因此，该技术可能更适合于分叉或比较细和短的肾动脉。此外，HIFU 应用超声波，而经导管RSD 消融术有X线辐射风险。尽管一次消融的治疗区域相对较小，但多次消融累积下来可达到预期的RSD 效果。更重要的是，无创RSD 可能更适合于普通高血压患者，而不仅仅局限于治疗难治性高血压。

与肾交感神经相关的拓展阅读：

• 去肾交感神经支配术的历史、应用及展望
• 去肾交感神经支配术的临床评估
• 去肾交感神经支配术用于顽固性高血压治疗原理 更多信息请点击：有关肾交感神经更多资讯

Noninvasive renal sympathetic denervation by extracorporeal high-intensity focused ultrasound in a preclinical canine model.
OBJECTIVES
The feasibility of noninvasive renal sympathetic denervation (RSD) using the novel approach of extracorporeal high-intensity focused ultrasound (HIFU) was investigated in this study.
BACKGROUND
Catheter-based RSD has achieved promising clinical outcomes.
METHODS
Under the guidance of Doppler flow imaging, therapeutic ablations (250 W×2 seconds) were performed by extracorporeal HIFU on the bilateral renal nerves (36.3±2.8 HIFU emissions in each animal) in an average 27.4-minute procedure in 18 healthy canines of the ablation group. Similar procedures without acoustic energy treatment were conducted in 5 canines of the sham group. The animals were sacrificed on day 6 or 28. The blood pressure (BP), plasma noradrenaline (NA) level and renal function were determined on days 0, 6 and 28. Pathological examinations were performed on all retrieved samples.
RESULTS
All of the animals survived the treatment. After ablation, the BP and NA significantly decreased compared to the baseline values (Bp changed -15.9/-13.6mmHg, NA changed -55.4%, p<0.001, respectively, on 28 days after ablation) and compared to the sham group on days 6 and 28. Ablation lesions around the renal artery adventitia were observed on day 6. A histologic examination revealed the disruption of nerve fibers, necrosis of Schwann cells and neurons, and apparent denervation on day 28. No procedure-related complications were observed.
CONCLUSIONS
Effective RSD was successfully achieved using the extracorporeal HIFU method in canines. Thus, noninvasive HIFU may be further explored as an important and novel strategy for RSD.