高頻電刺激指導(dǎo)腎動(dòng)脈射頻消融的實(shí)驗(yàn)研究

邱先狄， 劉 暢， 陳偉杰， 劉 航， 殷躍輝

(重慶醫(yī)科大學(xué)附屬第二醫(yī)院心內(nèi)科，重慶 400010)

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高頻電刺激指導(dǎo)腎動(dòng)脈射頻消融的實(shí)驗(yàn)研究

邱先狄， 劉 暢， 陳偉杰， 劉 航， 殷躍輝△

(重慶醫(yī)科大學(xué)附屬第二醫(yī)院心內(nèi)科，重慶 400010)

目的： 用電刺激的方法指導(dǎo)腎臟去神經(jīng)術(shù)(renal denervation，RDN)中射頻消融靶點(diǎn)的選擇，同時(shí)比較電刺激與射頻消融時(shí)血壓變化的異同。方法：成年健康昆明犬6只，行腎動(dòng)脈造影排除腎動(dòng)脈畸形后，每側(cè)腎動(dòng)脈從遠(yuǎn)段開始，由遠(yuǎn)及近選擇數(shù)個(gè)位點(diǎn)進(jìn)行電刺激并消融。連續(xù)記錄術(shù)中血壓的變化，術(shù)后通過軟件分析血壓的變化情況。采用常規(guī)HE和Masson染色觀察腎動(dòng)脈壁結(jié)構(gòu)及其周圍組織；采用酪氨酸羥化酶(tyrosine hydroxylase，TH)免疫組化染色觀察消融后腎動(dòng)脈去神經(jīng)效果。結(jié)果：本實(shí)驗(yàn)中刺激/消融位點(diǎn)共計(jì)50個(gè)，其中對電刺激有反應(yīng)的位點(diǎn)占34%，無反應(yīng)位點(diǎn)占66%。對有反應(yīng)位點(diǎn)進(jìn)行120 s電刺激時(shí)，其收縮壓按每20 s分段與基線血壓相比分別變化(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) mmHg；將120 s連續(xù)消融時(shí)的收縮壓數(shù)據(jù)同樣按每20 s與基線血壓相比，變化分別為(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) mmHg。無反應(yīng)位點(diǎn)進(jìn)行電刺激和射頻消融時(shí)均無明顯血壓升高。組織病理學(xué)檢查顯示，有反應(yīng)位點(diǎn)腎動(dòng)脈神經(jīng)面積為(0.51±0.28) mm2，無反應(yīng)位點(diǎn)處為 (0.09±0.06) mm2，差異有統(tǒng)計(jì)學(xué)顯著性(P<0.01)；免疫組化染色表明消融部位神經(jīng)TH的表達(dá)顯著低于未消融部位(P<0.01)。結(jié)論：高頻電刺激可以標(biāo)測腎交感神經(jīng)，且電刺激指導(dǎo)下的射頻消融能對腎動(dòng)脈交感神經(jīng)造成有效損傷。

腎交感神經(jīng)； 高頻電刺激； 射頻消融

腎交感神經(jīng)系統(tǒng)激活在難治性高血壓的發(fā)生發(fā)展中起重要作用[1]，并在動(dòng)脈粥樣硬化和心肌肥厚纖維化等方面有一定影響[2-3]。腎臟去交感神經(jīng)支配理論上可以降低腎臟以及全身交感神經(jīng)活性從而降低血壓[4]。以往有關(guān)Symplicity HTN-1、2的研究肯定了腎臟去神經(jīng)術(shù)(renal denervation，RDN)的安全性及有效性[5-6]，然而隨后開展的有關(guān)Symplicity HTN-3的研究結(jié)果顯示RDN術(shù)后的血壓降低與對照組相比差異無統(tǒng)計(jì)學(xué)顯著性[7]。有分析指出，Symplicity HTN-3研究中的血壓降低與消融靶點(diǎn)的數(shù)量呈正相關(guān)[8]，提示增加消融點(diǎn)數(shù)可以增加腎神經(jīng)損傷的幾率。但是腎動(dòng)脈周圍神經(jīng)分布在不同個(gè)體的變異非常大[9]，增加消融點(diǎn)數(shù)有增加腎動(dòng)脈損傷的潛在風(fēng)險(xiǎn)。因此本研究擬采用高頻電刺激對腎動(dòng)脈周圍神經(jīng)進(jìn)行標(biāo)測，找到神經(jīng)分布的位點(diǎn)，從而實(shí)現(xiàn)RDN中的靶向消融。

材 料 和 方 法

1 實(shí)驗(yàn)動(dòng)物

所有實(shí)驗(yàn)均通過重慶醫(yī)科大學(xué)動(dòng)物實(shí)驗(yàn)倫理委員會批準(zhǔn)，并嚴(yán)格按照國家衛(wèi)計(jì)委關(guān)于實(shí)驗(yàn)動(dòng)物飼養(yǎng)原則進(jìn)行。本實(shí)驗(yàn)采用的健康成年昆明犬有著很強(qiáng)的攻擊性，具有天然高血壓和高交感神經(jīng)活性，是本實(shí)驗(yàn)理想的實(shí)驗(yàn)動(dòng)物。取健康成年昆明犬6只(分別命名為E1～E6)，雌雄不拘，體重24～33 kg，平均(27.33±3.98) kg。

2 實(shí)驗(yàn)步驟

2.1 動(dòng)物預(yù)處理 動(dòng)物于實(shí)驗(yàn)當(dāng)天用3%的戊巴比妥鈉30 mg/kg腹腔注射，麻醉深度為實(shí)驗(yàn)犬眼瞼反射消失，術(shù)中觀察實(shí)驗(yàn)犬呼吸、肌肉張力、神經(jīng)反射及疼痛反應(yīng)的情況，并適時(shí)追加麻醉藥物。麻醉成功后，對雙側(cè)腹股溝、腰背部、四肢膝關(guān)節(jié)區(qū)域備皮；采用Seldinger技術(shù)行左、右股動(dòng)脈穿刺，分別放置6F和8F的鞘管，6F鞘管用于連續(xù)記錄有創(chuàng)血壓，8F鞘管作為消融導(dǎo)管的送入路徑。

2.2 雙側(cè)腎動(dòng)脈造影 在數(shù)字減影血管造影(digi-tal subtraction angiography，DSA)下，沿導(dǎo)引鋼絲將JR4.0/3.5造影導(dǎo)管(Cordis)送至左、右腎動(dòng)脈開口處行選擇性腎動(dòng)脈造影，排除畸形、過短(<20 mm)及狹窄的腎動(dòng)脈。

2.3 腎動(dòng)脈電刺激及消融 經(jīng)腎動(dòng)脈造影后，每側(cè)腎動(dòng)脈從遠(yuǎn)段開始，由遠(yuǎn)及近選擇數(shù)個(gè)位點(diǎn)進(jìn)行電刺激和消融，電刺激和消融間隔2 min。使用4極6F溫控消融導(dǎo)管(Johnson)進(jìn)行腎動(dòng)脈電刺激，無論電刺激時(shí)是否有血壓升高的反應(yīng)均在刺激點(diǎn)行射頻消融去神經(jīng)治療。電刺激設(shè)置參數(shù)為電壓8 V，頻率20 Hz，刺激時(shí)間為120 s；射頻消融設(shè)置參數(shù)為功率10 W，溫度45 ℃，消融時(shí)間為120 s。消融時(shí)嚴(yán)密監(jiān)測阻抗、溫度、血壓和心率的變化。

2.4 血壓測量分析 肝素鹽水沖洗連接管，排除氣泡，血壓校零，通過LEAD2000心臟電生理記錄儀(四川成都錦江電子科技有限公司)連續(xù)記錄每搏有創(chuàng)血壓。每個(gè)位點(diǎn)刺激前取20 s的平均血壓數(shù)據(jù)作為基線血壓；將刺激時(shí)的血壓數(shù)據(jù)按照時(shí)間順序分為6段，分別為A(0～20 s)、B(21～40 s)、C(41～60 s)、D(61～80 s)、E(81～100 s)和F(101～120 s)；消融的血壓數(shù)據(jù)按時(shí)間順序分為6段，分別為G(0～20 s)、H(21～40 s)、I(41～60 s)、J(61～80 s)、K(81～100 s)和L(101～120 s)。用各時(shí)段內(nèi)的收縮壓均值來表征此段時(shí)間的血壓水平。取各段血壓均值與基線均值的差值，來代表各時(shí)段的血壓變化情況。據(jù)以往的研究[8]，將電刺激/消融時(shí)收縮壓持續(xù)升高≥10 mmHg定義為有反應(yīng)位點(diǎn)。

2.5 標(biāo)本采集與組織學(xué)檢查 手術(shù)1周后，采用3%戊巴比妥鈉溶液麻醉對實(shí)驗(yàn)犬處以安樂死，取雙側(cè)腎動(dòng)脈及其周圍組織，用藍(lán)色縫線標(biāo)記腎動(dòng)脈開口前壁，紅色縫線標(biāo)記腎動(dòng)脈開口上壁；浸泡于4%甲醛溶液中固定，室溫24 h，根據(jù)組織塊的大小，適當(dāng)延長或縮短固定時(shí)間；組織固定完成后行石蠟包埋并切片，切片位點(diǎn)按照腎動(dòng)脈消融時(shí)的影像資料確定，以保證切片與消融位點(diǎn)的對應(yīng)。每個(gè)位點(diǎn)各取5張切片(4 μm厚度)，將標(biāo)定好方位的切片進(jìn)行HE、Masson及酪氨酸羥化酶(tyrosine hydroxylase，TH)免疫組化染色后采用Image-Pro Plus 6.0圖像軟件對顯微影像照片進(jìn)行測量分析。

3 統(tǒng)計(jì)學(xué)處理

本報(bào)告采用Excel 365進(jìn)行數(shù)據(jù)整理，IBM SPSS 22.0進(jìn)行數(shù)據(jù)分析，計(jì)量資料采用均數(shù)±標(biāo)準(zhǔn)差(mean±SD)表示，重復(fù)測量資料采用重復(fù)測量方差分析，采用協(xié)方差分析比較兩組手術(shù)各時(shí)段結(jié)果之間的差異(協(xié)變量為基線數(shù)據(jù))，方差分析后的兩兩組間比較釆用Bonferroni法,以P<0.05為差異有統(tǒng)計(jì)學(xué)意義。

結(jié) 果

1 雙側(cè)腎動(dòng)脈電刺激及消融

在數(shù)字減影血管造影引導(dǎo)下，沿導(dǎo)引鋼絲送入JR4.0導(dǎo)引導(dǎo)管逆行至左右腎動(dòng)脈開口處行腎動(dòng)脈造影，雙側(cè)腎動(dòng)脈造影排除腎動(dòng)脈畸形、過短及狹窄(實(shí)際入組5條犬，共計(jì)9條腎動(dòng)脈。E2號實(shí)驗(yàn)犬右腎動(dòng)脈為雙腎動(dòng)脈，予以排除；E6號術(shù)后死亡，亦排除)。術(shù)前及術(shù)后造影結(jié)果如圖1所示，刺激消融位點(diǎn)分布如圖2、3所示。

Figure 1.Renal artery DSA of the E1 dog before and after operation.

圖1 E1腎動(dòng)脈電刺激及消融術(shù)前及術(shù)后數(shù)字減影血管造影

2 腎動(dòng)脈HE染色

正常腎動(dòng)脈未見明顯形態(tài)學(xué)及細(xì)胞學(xué)變化。消融部位腎動(dòng)脈HE染色可見內(nèi)彈性膜波浪走形消失、偶可見斷裂，未見明顯內(nèi)皮細(xì)胞增生；中膜變薄，平滑肌玻璃樣變性，呈嗜伊紅均質(zhì)狀，細(xì)胞核消失、細(xì)胞壞死，偶見炎性細(xì)胞；腎動(dòng)脈外膜界限清楚，可見小血管及橫截面大小不等的扁圓形神經(jīng)纖維分布其中，對應(yīng)消融位點(diǎn)外膜中的神經(jīng)纖維可見神經(jīng)細(xì)胞結(jié)構(gòu)模糊、呈嗜伊紅均質(zhì)狀、細(xì)胞核消失、偶見炎性細(xì)胞，見圖4。

腎動(dòng)脈HE染色可見外膜中存在橫截面為扁圓形的多個(gè)神經(jīng)纖維束，包膜完整，神經(jīng)纖維排列呈波浪狀，細(xì)胞核清晰可見，細(xì)胞間分界清楚；消融部位神經(jīng)束形態(tài)結(jié)構(gòu)尚存，橫截面神經(jīng)纖維排列紊亂，大部分區(qū)域未見明顯細(xì)胞核，呈凝固性壞死，見圖5。

3 TH免疫組化染色

TH免疫組化顯示，未消融部位腎動(dòng)脈外膜的神經(jīng)纖維束染色呈陽性(胞漿呈黃色)；消融部位腎動(dòng)脈外膜處神經(jīng)纖維束TH表達(dá)呈陰性或弱陽性。平均吸光度反映所選對象上免疫反應(yīng)物的表達(dá)強(qiáng)度，消融和未消融部位的平均吸光度分別為0.031±0.015和0.085±0.018(P<0.01)，兩者間差異有統(tǒng)計(jì)學(xué)顯著性，故認(rèn)為消融后TH表達(dá)明顯下降，見圖6。

4 有反應(yīng)組和無反應(yīng)組的腎動(dòng)脈周圍神經(jīng)分布

病理組織學(xué)檢查發(fā)現(xiàn)對消融有反應(yīng)區(qū)域的神經(jīng)面積顯著高于無反應(yīng)區(qū)域(P<0.01)，見圖7。

Figure 2.The target distribution of transcatheter renal artery electrical stimulation and ablation of the right renal artery in the E1 dog. A: distal segment superior wall; B: middle superior wall; C: near superior wall; D: distal segment inferior wall; E: middle inferior wall; F: near inferior wall.

圖2 數(shù)字減影血管造影顯示E1犬右側(cè)腎動(dòng)脈經(jīng)導(dǎo)管腎動(dòng)脈電刺激及消融的靶點(diǎn)分布

Figure 3.The target distribution of transcatheter renal artery electrical stimulation and ablation of the left renal artery in the E1 dog. A: near superior wall; B: middle inferior wall; C: distal segnment superior wall; D: middle superior wall.

圖3 數(shù)字減影血管造影顯示E1犬左側(cè)腎動(dòng)脈經(jīng)導(dǎo)管腎動(dòng)脈電刺激及消融的靶點(diǎn)分布

5 Masson染色

Masson染色顯示，消融部位腎動(dòng)脈中膜變薄、正常平滑肌細(xì)胞由藍(lán)染的膠原纖維所替代，見圖8。

6 刺激及消融時(shí)血壓的變化

本實(shí)驗(yàn)中將電刺激/消融時(shí)收縮壓持續(xù)升高≥10 mmHg定義為有反應(yīng)位點(diǎn)(圖9)，通過統(tǒng)計(jì)學(xué)分析顯示：(1)本實(shí)驗(yàn)中刺激/消融位點(diǎn)共計(jì)50個(gè)，其中有反應(yīng)位點(diǎn)占34%，無反應(yīng)位點(diǎn)占66%；(2)有反應(yīng)位點(diǎn)的收縮壓在連續(xù)電刺激的41～100 s和消融的41～80 s持續(xù)升高并超過基線10 mmHg；(3)對無反應(yīng)位點(diǎn)進(jìn)行連續(xù)電刺激和消融時(shí)，各時(shí)段收縮壓與基線相比無明顯升高；(4)有反應(yīng)組與無反應(yīng)組在刺激的41～120 s和消融的41～120 s時(shí)的血壓變化差異有統(tǒng)計(jì)學(xué)顯著性(P<0.05)；(5)在有反應(yīng)組中，0～100 s時(shí)間內(nèi)，刺激和消融時(shí)的血壓變化差異無統(tǒng)計(jì)學(xué)顯著性，在101～120 s內(nèi)差異有統(tǒng)計(jì)學(xué)顯著性(P<0.05)；(6)在無反應(yīng)組中，0～120 s時(shí)間內(nèi)，刺激和消融時(shí)的血壓變化差異無統(tǒng)計(jì)學(xué)顯著性；(7)在有反應(yīng)組中，消融時(shí)血壓升高的峰值較刺激時(shí)提前；(8)有反應(yīng)組消融最后20 s的血壓與基線相比顯著下降，見表1。

Figure 4.Canine renal arterial wall with HE staining. A: non-ablation area; B: ablation area.

圖4 犬腎動(dòng)脈壁HE染色結(jié)果

討 論

本研究結(jié)果表明實(shí)驗(yàn)中34%的位點(diǎn)在電刺激時(shí)血壓升高超過基線10 mmHg，這些位點(diǎn)在消融時(shí)有相似的血壓變化，而66%的位點(diǎn)在電刺激和消融時(shí)的血壓與基線相比無明顯變化；在有反應(yīng)組中，刺激和消融時(shí)血壓的變化有相似性，但消融時(shí)血壓升高的峰值提前，消融后期血壓有一個(gè)顯著的下降；組織病理學(xué)檢查發(fā)現(xiàn)，與無反應(yīng)位點(diǎn)相比，有反應(yīng)位點(diǎn)腎動(dòng)脈外膜中的神經(jīng)纖維數(shù)量明顯較多；消融部位的神經(jīng)TH表達(dá)減弱、甚至不表達(dá)，提示射頻消融對腎動(dòng)脈周圍神經(jīng)能造成明顯損傷。

以往的RDN術(shù)因?yàn)闊o法確定合適的消融位點(diǎn)，通常采用增加雙側(cè)腎動(dòng)脈的消融點(diǎn)數(shù)來提高腎臟去神經(jīng)的成功率，有分析認(rèn)為，Symplicity HTN-3研究中的血壓降低與消融靶點(diǎn)的數(shù)量呈正相關(guān)[10]，然而腎動(dòng)脈周圍神經(jīng)分布的情況在不同個(gè)體的變異非常大[9]，術(shù)中并不能確定所選擇的消融位點(diǎn)其周圍一定存在神經(jīng)分布，增加消融點(diǎn)數(shù)有可能增加神經(jīng)損傷的幾率，但也可能會造成腎動(dòng)脈過度損傷，導(dǎo)致狹窄、夾層和血栓等手術(shù)并發(fā)癥的概率增加。本實(shí)驗(yàn)中僅有34%的位點(diǎn)對刺激/消融存在反應(yīng)，通過進(jìn)一步的組織病理學(xué)檢查我們發(fā)現(xiàn)，有反應(yīng)位點(diǎn)的腎動(dòng)脈外膜中的神經(jīng)纖維明顯較多。有研究表明腎動(dòng)脈外膜中的神經(jīng)束由交感、副交感神經(jīng)和傳入神經(jīng)共同構(gòu)成，分別占73.5%、17.9%和8.7%[11]，因此，標(biāo)測傳入神經(jīng)后在消融時(shí)能夠同時(shí)破壞這3種神經(jīng)引起血壓降低。雖然此實(shí)驗(yàn)中刺激和消融時(shí)的血壓變化有相似的升高，但消融時(shí)的血壓升高峰值提前，可能因?yàn)橄诔跗谏窠?jīng)尚未被破壞，且消融時(shí)的電流密度較大，使得腎動(dòng)脈周圍神經(jīng)的神經(jīng)沖動(dòng)較高，傳入中樞交感神經(jīng)系統(tǒng)后進(jìn)一步激活全身交感神經(jīng)系統(tǒng)活性所致。而在消融末期(101～120 s)血壓低于基線值，可能是盡管仍然存在電流的刺激，由于腎動(dòng)脈周圍神經(jīng)受到了有效的破壞，使得射頻電流刺激不能沿著傳入神經(jīng)纖維進(jìn)入交感中樞，無法產(chǎn)生血壓升高的反應(yīng)。而電刺激末期(101～120 s)血壓下降至基線水平，之前的研究中[12]并未發(fā)現(xiàn)此現(xiàn)象，我們猜測可能因?yàn)榇藢?shí)驗(yàn)中刺激時(shí)間較長(120 s)，而之前的實(shí)驗(yàn)僅刺激60 s，使神經(jīng)傳導(dǎo)中神經(jīng)遞質(zhì)耗竭有關(guān)，盡管電刺激持續(xù)存在，也不能再產(chǎn)生相同的血壓升高效應(yīng)。免疫組化染色可見消融位點(diǎn)的腎動(dòng)脈周圍神經(jīng)的TH表達(dá)明顯下降，間接反映神經(jīng)功能下降甚至喪失，表明其對神經(jīng)可產(chǎn)生有效損傷。以上實(shí)驗(yàn)結(jié)果說明在RDN術(shù)中，之前的“盲目”消融對腎動(dòng)脈神經(jīng)的損傷是不確定的，用電刺激的方法對RDN術(shù)中消融靶點(diǎn)的選擇有一定的指導(dǎo)意義。

Figure 5.Canine renal artery nerves with HE staining. A: outer membrane nerves of renal artery in non-ablation parts; B: outer membrane nerves of renal artery in ablation parts.

圖5 犬腎動(dòng)脈周圍神經(jīng)HE染色結(jié)果

Figure 6.TH immunohistochemical staining of canine renal artery. A: peripheral nerves of renal artery in non-ablation parts; B: peripheral nerves of renal artery in ablation parts.

圖6 犬腎動(dòng)脈TH免疫組化染色

Figure 7.Peripheral nerve distribution of different response points (Masson staining,×40). A: response point; B: non-response point.Yellow curve was the vascular wall under electrical stimulation and ablation.

圖7 不同反應(yīng)點(diǎn)的周圍神經(jīng)分布

Figure 8.Masson staining of canine renal artery ablation sites(×40). Yellow curve was the ablation area.

圖8 犬腎動(dòng)脈消融位點(diǎn)的Masson染色

Figure 9.Blood pressure (BP) changes of response sites in renal artery under electrical stimulation and ablation. A: the baseline blood pressure; B: electrical stimulation started; C: blood pressure elevated under electrical stimulation; D: ablation started; E: blood pressure elevated under ablation.

圖9 腎動(dòng)脈電刺激和消融時(shí)有反應(yīng)位點(diǎn)的血壓變化

表1 電刺激和消融各時(shí)段的血壓相對于基線的變化

ES: electrical stimulation; RF: radiofrequency ablation.

雖然此實(shí)驗(yàn)觀察到了對電刺激有反應(yīng)的位點(diǎn)進(jìn)行消融后能達(dá)到對腎動(dòng)脈去神經(jīng)有效，但樣本數(shù)量少，需更大樣本的研究進(jìn)一步證實(shí)；本實(shí)驗(yàn)僅觀察了即刻的血壓變化情況，缺少術(shù)后遠(yuǎn)期的血壓隨訪；通過組織病理學(xué)檢查能夠確定消融對有反應(yīng)的靶點(diǎn)達(dá)到了完全的去神經(jīng)，但其它位點(diǎn)仍然存在未能損傷的神經(jīng)，故下一步的研究中應(yīng)把如何完整標(biāo)測腎動(dòng)脈，從而對腎動(dòng)脈完全去神經(jīng)作為重點(diǎn)。

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(責(zé)任編輯： 盧 萍， 羅 森)

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

QIU Xian-di, LIU Chang, CHEN Wei-jie, LIU Hang, YIN Yue-hui

(DepartmentofCardiology,TheSecondAffiliatedHospital,ChongqingMedicalUniversity,Chongqing400010,China.E-mail:yinyh63@163.com)

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.

Renal sympathetic nerve; High-frequency electrical stimulation; Radiofrequency ablation

1000- 4718(2016)10- 1763- 07

2016- 05- 19

2016- 07- 22

△通訊作者 Tel: 023-63693065; E-mail: yinyh63@163.com

R363

A

10.3969/j.issn.1000- 4718.2016.10.006

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