李長永, 張志鋼, 白 元, 秦永文
經(jīng)皮左心耳封堵裝置研究進(jìn)展
李長永,張志鋼,白元,秦永文
·綜述General review·
心房纖維顫動(dòng)(房顫)是最常見的心律失常之一,房顫患者發(fā)生腦卒中的風(fēng)險(xiǎn)很大。口服抗凝藥物預(yù)防腦卒中存在出血風(fēng)險(xiǎn),部分患者不能耐受。經(jīng)皮左心耳封堵在房顫患者預(yù)防腦卒中方面安全有效,目前還只適用于存在抗凝禁忌的患者。本文回顧了近年來應(yīng)用的多種左心耳封堵裝置,分析不同形狀設(shè)計(jì)的裝置與左心耳形態(tài)的關(guān)系。
心房纖維顫動(dòng);左心耳封堵,心房封閉裝置
心房纖維顫動(dòng)(房顫)是最常見的心律失常之一,全球范圍內(nèi)影響約總?cè)丝诘?%,且發(fā)病率呈逐年上升趨勢(shì),預(yù)計(jì)未來40年內(nèi)其發(fā)病率將上升5倍。房顫患者發(fā)生腦卒中的風(fēng)險(xiǎn)較普通人群高5倍;15%~20%缺血性腦卒中與房顫有關(guān)[1]??鼓委熑匀皇悄壳邦A(yù)防房顫腦卒中的主要手段,但相當(dāng)一部分患者存在抗凝治療的相對(duì)或絕對(duì)禁忌證。華法林治療窗窄,需要監(jiān)測(cè)凝血酶原時(shí)間、國際正?;戎担↖NR),藥物相互作用多,出血風(fēng)險(xiǎn)較高,患者依從性差[2]。新型口服抗凝藥物,包括達(dá)比加群、阿哌沙班、利伐沙班等,被證實(shí)不劣于華法林,但仍然存在出血風(fēng)險(xiǎn),且費(fèi)用昂貴[3]??鼓委煹牟蛔愦偈谷藗儗で笮碌氖侄晤A(yù)防房顫腦卒中。證據(jù)表明左心耳是房顫患者血栓形成最常見的部位,約90%血栓形成于此[4]。通過物理手段封閉左心耳來預(yù)防腦卒中可用于存在抗凝禁忌的房顫患者,是目前研究熱點(diǎn)。
外科方面,Madden等[5]早于1949年就為房顫患者開胸手術(shù)過程中實(shí)施左心耳切除術(shù),并提出房顫患者實(shí)施開胸手術(shù)的過程中,行左心耳切除術(shù)預(yù)防腦卒中是可行的。左心耳封閉研究(leftatrialappendage occlusion study,LAAOS)首次評(píng)估了房顫患者在擇期冠脈旁路移植術(shù)中行左心耳封閉的安全可行性,術(shù)后8周經(jīng)食管超聲證實(shí)左心耳完全封閉率在裝訂裝置和單純縫扎分別為72%和45%,結(jié)果不盡人意[6]。同樣,一份納入5項(xiàng)研究的Meta分析發(fā)現(xiàn)外科術(shù)中行左心耳封閉并未給患者帶來益處,其主要問題是常常不能完全隔離左心耳,殘余漏的形成反而可能增加血栓栓塞的風(fēng)險(xiǎn)[7]。另外,對(duì)于無其他開胸手術(shù)指征的房顫患者,單純開胸行左心耳關(guān)閉創(chuàng)傷過大,患者一般難以接受。
通過介入封堵手段來實(shí)現(xiàn)左心耳的封閉創(chuàng)傷小,患者易接受,且已被證實(shí)安全可行。目前有多種介入封堵左心耳裝置已用于臨床,其中研究較多的是 PLAATO、Watchman、Amplatzer Cardiac Plug和LARIAT等裝置[8](圖1)。除LARIAT之外,其他裝置均通過股靜脈及房間隔穿刺途徑進(jìn)入,輸送鞘管一般需9~14 F。LARIAT則需要血管和心包雙途徑,心包途徑的建立僅需胸壁很小的切口[9]。不同封堵裝置的形狀設(shè)計(jì)差別很大,能否完全封閉左心耳很大程度上取決于左心耳本身的形態(tài),選擇適合心耳形態(tài)的封堵裝置可提高封堵成功率。左心耳形態(tài)、深度、開口位置和大小,及其與肺靜脈的關(guān)系均存在較大變異性,不同形態(tài)的心耳形成血栓的風(fēng)險(xiǎn)也不同[10]。心臟MRI、CT和3D經(jīng)食管超聲被認(rèn)為對(duì)確定左心耳形態(tài)具有較高價(jià)值[11],而2D經(jīng)食管超聲被認(rèn)為會(huì)低估左心耳深度和開口大?。?2]。利用多種影像手段綜合測(cè)量左心耳形態(tài)、開口直徑及其與毗鄰結(jié)構(gòu)的關(guān)系,選擇合適形狀和大小的裝置,可提高封堵成功率,減少并發(fā)癥發(fā)生[13-14]。
圖1 目前各類經(jīng)皮左心耳封堵裝置
PLAATO裝置的動(dòng)物試驗(yàn)開始于 2001年[15],2002年便首次用于臨床。封堵器由自膨脹鎳鈦合金籠狀結(jié)構(gòu)和聚四氟乙烯膜組成,骨架上有3排倒鉤,起到固定于左心耳內(nèi)的作用。直徑為15~32 mm,選擇較左心耳直徑大20%~40%的裝置進(jìn)行封堵,需14 F輸送鞘[16]。一項(xiàng)研究納入111例有抗凝禁忌征的非瓣膜性房顫患者,成功封堵率97.3%。3例未成功植入封堵器的患者分別因?yàn)榇嬖谧蠓垦ā?dǎo)致股動(dòng)脈血腫、房間隔穿刺導(dǎo)致心臟壓塞。封堵器可完全回收和再釋放。術(shù)后終生服用阿司匹林和氯吡格雷抗栓。6個(gè)月隨訪時(shí)有2例患者發(fā)生缺血性腦卒中,3例患者發(fā)生短暫性腦缺血發(fā)作(TIA),年腦卒中或TIA發(fā)生率為2.2%[17]。5年隨訪年腦卒中或TIA發(fā)生率為3.8%,根據(jù)患者CHADS2評(píng)分,其預(yù)計(jì)年腦卒中發(fā)生率為6.6%[18]。另一項(xiàng)歐洲研究納入180例患者,術(shù)中發(fā)生6例心臟壓塞和1例裝置栓塞,即刻封堵成功率為90%,術(shù)后年腦卒中或TIA發(fā)生率為2.3%,該研究出于經(jīng)費(fèi)方面的原因提前終止[19]。
Watchman裝置是目前唯一被美國FDA批準(zhǔn)的用于左心耳封堵的裝置[20]。封堵器鎳鈦合金骨架形狀類似“水母”,外覆聚酯纖維膜,并有倒鉤起到固定于心耳內(nèi)的作用。封堵器有21、24、27、30、33 mm 等5種尺寸,選擇較左心耳開口直徑大10%~20%的封堵器,需12 F輸送鞘。借助豬尾巴導(dǎo)管將輸送鞘送至心耳深處,封堵器到位后,通過回撤輸送鞘釋放封堵器。
2007年Watchman裝置首次用于臨床[21]。最初16例患者接受的是Watchman第一代封堵器,發(fā)生2例裝置栓塞,1例輸送鞘損壞。通過對(duì)封堵器的倒鉤進(jìn)行改進(jìn),隨后的53例患者未發(fā)生類似情況。隨訪2年時(shí)無腦卒中或TIA事件發(fā)生,根據(jù)CHADS2評(píng)分預(yù)計(jì)的口服華法林年腦卒中發(fā)生率為3.2%[21]。
PROTECT AF研究比較了Watchman在非瓣膜性房顫患者中與抗凝治療的療效與安全性。有效性指標(biāo)是系統(tǒng)性栓塞、心血管死亡、腦卒中的復(fù)合終點(diǎn)。研究中Watchman植入后繼續(xù)服用華法林45 d,直至裝置表面內(nèi)皮化完成,之后服用氯吡格雷6個(gè)月,阿司匹林終生。最終試驗(yàn)組408例患者,裝置植入成功率91%,對(duì)照組241例。兩組在大出血方面有統(tǒng)計(jì)學(xué)差異,分別為4.1%和3.5%??偟哪X卒中發(fā)生率(包括缺血性和出血性腦卒中)方面,介入組低于對(duì)照組。該研究初步證實(shí)左心耳封堵是安全有效的[22-24]。
PREVAIL研究與PROTECT AF研究設(shè)計(jì)思路相似,但納入的患者排除了CHADS2評(píng)分為1分的患者。介入組手術(shù)相關(guān)并發(fā)癥較PROTECT AF研究有明顯降低(分別為2.2%和2.67%),相應(yīng)地,手術(shù)成功率也明顯提高(分別為90.9%和95.1%)。這進(jìn)一步證實(shí)了Watchman裝置的安全性。然而研究定義的復(fù)合終點(diǎn)包括腦卒中、系統(tǒng)性栓塞、心血管死亡在介入組和華法林組并無差異。
LARIAT除房間隔穿刺途徑(8.5 F鞘管)之外還需要心包途徑(14 F鞘管),需使2個(gè)途徑的導(dǎo)絲靠磁性接合,再經(jīng)心包途徑對(duì)左心耳進(jìn)行套扎。由于心腔內(nèi)不植入異物,不會(huì)導(dǎo)致裝置栓塞及裝置血栓形成。
最初一項(xiàng)研究納入了21例不適合抗凝治療的房顫患者。術(shù)中發(fā)生1例右室穿孔導(dǎo)致心臟壓塞需外科處理,1例患者心包積液需心包引流,3例患者術(shù)后出現(xiàn)心包炎再次住院。左心耳封堵成功率為100%,平均隨訪1年余,左心耳均未再開通[25]。另一項(xiàng)研究納入了27例患者,92.4%患者成功封堵,1例患者發(fā)生左心耳穿孔,1例患者未能成功對(duì)左心耳進(jìn)行套扎[26]。LARIAT裝置導(dǎo)致的心包炎在術(shù)后并不少見,常需要抗炎治療,目前考慮主要與心耳套扎線引起的局部炎癥有關(guān)。圍術(shù)期存在右室破裂、心耳穿孔等嚴(yán)重并發(fā)癥,可能與裝置本身缺陷及術(shù)者操作經(jīng)驗(yàn)少有關(guān)。
ACP裝置是由鎳鈦合金和聚酯纖維膜組成,包括一葉狀結(jié)構(gòu)和一個(gè)盤片組成,中間細(xì)腰連接,盤片比葉狀結(jié)構(gòu)稍大,覆蓋于左心耳口,通過10~13 F鞘管輸送。裝置根據(jù)葉狀結(jié)構(gòu)的直徑,裝置有16~30 mm不同型號(hào),通常選擇比左心耳體部最小直徑大10%~20%的裝置[27]。葉狀結(jié)構(gòu)放置于距心耳開口約1 cm處,通過回撤輸送鞘釋放盤面覆蓋于心耳口。
1項(xiàng)歐洲研究納入了143例患者,成功封堵率96%,5例發(fā)生心包積液,3例缺血性腦卒中,2例裝置栓塞[28]。德國的1項(xiàng)小型研究納入了34例患者,發(fā)現(xiàn)術(shù)后雙抗血小板的患者有17.6%存在食管超聲證實(shí)的裝置血栓形成,大多數(shù)血栓位于盤面中間螺絲的位置,研究者認(rèn)為ACP裝置盤面比Watchman大,有更大的血栓形成的風(fēng)險(xiǎn)[29]。
基于以上這些缺陷,第二代ACP進(jìn)行了改進(jìn),葉狀結(jié)構(gòu)更長,盤面也更大,型號(hào)變?yōu)?6~34 mm,可以用來封堵更大的左心耳,一般推薦選擇較左心耳口大3~6 mm的裝置。葉狀結(jié)構(gòu)上的倒鉤增多,硬度較前變大,可以更好地固定于左心耳體部。裝置預(yù)載于輸送鞘內(nèi),減少了空氣栓塞、裝置栓塞的發(fā)生[30]。
LAmbre由一盤面和帶有倒鉤的傘狀結(jié)構(gòu)組成,中間有一腰連接。盤面比傘狀結(jié)構(gòu)大4~6 mm,裝置有16~36 mm不同型號(hào),通常選擇較左心耳大4~8 mm的裝置。輸送鞘管送至左心耳近端,通過前送推送桿將傘狀結(jié)構(gòu)送至合適的錨著位置后,再回撤輸送鞘管釋放盤面時(shí)期覆蓋于左心耳口。裝置有二大優(yōu)勢(shì):更小的輸送鞘管、倒鉤設(shè)計(jì)使其可安全回收和再釋放[31]。
尚有一些新型裝置正在研究之中。AEGIS系統(tǒng)是由心包途徑對(duì)左心耳進(jìn)行圈,Coherex WaveCrest與大多數(shù)經(jīng)血管途徑裝置相似,這2種裝置還在動(dòng)物實(shí)驗(yàn)階段[32]。Transcatheter Patch設(shè)計(jì)較為獨(dú)特,該裝置沒有鎳鈦合金骨架,僅有一補(bǔ)片和支撐球囊組成,二者分別為乳膠和聚氨酯泡沫,均為可吸收材料。球囊放置于左心耳內(nèi),通過外科粘合劑固定于心耳內(nèi),減少穿孔機(jī)會(huì),補(bǔ)片覆蓋于左心耳口,已經(jīng)應(yīng)用于20例患者[33]。
經(jīng)皮左心耳封堵已被證實(shí)在房顫患者預(yù)防腦卒中方面安全有效,目前還只適用于存在抗凝禁忌的患者。目前的各類裝置設(shè)計(jì)差別很大,根據(jù)左心耳的形態(tài)特點(diǎn)選擇合適的封堵器可能會(huì)較少并發(fā)癥的發(fā)生。目前裝置尚存在一些不足,新型裝置也在不斷研發(fā)之中,隨著裝置的不斷改進(jìn),經(jīng)皮左心耳封堵預(yù)防房顫腦卒中有很大的應(yīng)用前景。
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Devices used for percutaneous occlusion of left atrial appendage:recent progress in research
LI Chang-yong,ZHANG Zhi-gang,BAI Yuan,QIN Yong-wen.Department of Cardiology,General Hospital of Jinan Military Command,Jinan,Shandong Province 250000,China
QIN Yong-wen,E-mail:qyw2009@163.com
Clinically,atrial fibrillation(AF)is one of the most common cardiac arrhythmia,and patients with arterial fibrillation carry high risk of stroke.Oral administration of anticoagulation such as warfarin for the prevention of stroke has some risks to induce bleeding;moreover,some patients are not able to tolerate the medication.Percutaneous occlusion of the left atrial appendage is safe and effective for the prevention of stroke in patients with atrial fibrillation,although at present it is only used for the patients who have contraindications to anticoagulation medication.This paper aims to review a variety of left atrial appendage occlusion devices and to analyze the relationship between the different shape design of occluder and the left atrial appendage morphology.(J Intervent Radiol,2015,24:830-834)
atrial fibrillation;occlusion of left atrial appendage;atrial closure device
R541.75
A
1008-794X(2015)-09-0830-05
2015-02-03)
(本文編輯:俞瑞綱)
10.3969/j.issn.1008-794X.2015.09.022
250031濟(jì)南 濟(jì)南軍區(qū)總醫(yī)院心內(nèi)科(李長永);第二軍醫(yī)大學(xué)長海醫(yī)院心內(nèi)科(張志鋼、白元、秦永文)
秦永文E-mail:qyw2009@163.com