Treatment of AVM: Endovascular Methods(1) AVM的治療:血管內(nèi)介入方法 Emmanuel Houdart, Marc Antoine Labeyrie, Stéphanie Lenck, and Jean Pierre Saint-Maurice 1 Summary In this chapter we review the technical aspects, the indications, and the results of endovascular treatment of intracranial arteriovenous malformation (AVM). From an endovascular perspective, AVM is a hemodynamic vascular area connecting the high-pressure arterial system with the low-pressure venous system by means of arteriovenous shunts. The low-pressure venous system exerts suction on the arterial system and if the arteries supplying the shunts are occluded in a proximal manner, arterial anastomoses develop from adjacent arteries and resupply the shunts. This supports the distinction between proximal embolization that occludes arteries and preserves shunts and distal (or curative) embolization where embolic agent is pushed up to the draining vein. The standard technique of embolization uses the transarterial approach that consists in superselective catheterization of the arterial feeders and injection of embolic agents through microcatheters. Two types of liquid embolic agents are used at Lariboisière: cyanoacrylate (Glubran) and EVOH Copolymer-DMSO solvent (Onyx). Glubran is used through perforating and small cortical arteries while Onyx is used through large cortical arteries. Proximal arterial occlusion makes sense only in pre-surgical embolization. On the other hand, when embolization is the sole treatment or when it is performed to reduce the size of an AVM before radiosurgery, the embolic agent must be pushed up to the first centimeter of the draining vein. This venous occlusion carries on a risk of rupture of the shunts if all the arterial feeders going to the shunts have not been first occluded. By transarterial approach, the success of the procedure (defined as an angiographic cure with unchanged neurological examination) depends on several factors that participate to our personal score: perforating arteries (yes = 1, no = 0), en passage arteries (yes = 1, no = 0), watershed area supply (yes = 1, no = 0), size >3 cm (yes = 1, no = 0). A high score is predictive of a poor result. Recently, transvenous embolization has been developed with the help of Onyx. This technique has not been assessed in large series and its hazard is still unknown. We restrict transvenous embolization to small AVM located in very functional area, fed by small arteries with difficult access and drained by an accessible vein. Main risk of any types of embolization is the hemorrhage that occurs when part of the shunts remains patent. The key point concerning the indications of treatment is related to unruptured AVM. Two recent prospective studies using control groups (with patients left untreated) have questioned the benefit of treatment of unruptured AVM. Currently, unruptured AVM are left untreated in their vast majority. Ruptured AVM have a higher risk to bleed than unruptured ones and indications of treatment are larger in such cases. However, when the neurological risk linked to the occlusion of the totality of the arteriovenous shunts is high, we restrict our treatment to the part of the AVM that has been recognized as responsible of the bleeding. Endovascular treatment of AVM is the intervention that requires the longest training in interventional neuroradiology. 1 總結(jié) 本章我們回顧顱內(nèi)動靜脈畸形的技術(shù)方面,適應(yīng)癥,和血管內(nèi)治療的結(jié)果。從血管內(nèi)介入的觀點,AVM是血流動力學(xué)血管病變區(qū)域,通過動靜脈瘺單元聯(lián)系高壓的動脈系統(tǒng)和低壓的靜脈系統(tǒng)。低壓的靜脈系統(tǒng)抽吸動脈系統(tǒng),如果供應(yīng)瘺的動脈在近端阻斷,臨近動脈重新建立動脈吻合并再次供應(yīng)瘺。這點支持動脈近端栓塞而保留瘺和遠(yuǎn)端(或治愈性)栓塞其栓塞劑注入靜脈兩種治療體系的區(qū)別。栓塞的標(biāo)準(zhǔn)技巧采取經(jīng)動脈入路,包括供血動脈的微導(dǎo)管超選和經(jīng)微導(dǎo)管栓塞劑的注射。兩種液態(tài)栓塞劑在 Lariboisière醫(yī)院可被采用: cyanoacrylate (Glubran) and EVOH Copolymer-DMSO solvent(Onyx). Glubran被用于穿支動脈和細(xì)小皮層動脈而Onyx被用于大的皮層動脈。近端動脈栓塞僅在開顱術(shù)前輔助栓塞有意義。另一方面,當(dāng)栓塞是AVM唯一治療選擇或當(dāng)栓塞是為了放療前減少血流量時,栓塞劑必須注射到引流靜脈的最初的1cm距離。如果所有的供應(yīng)瘺的供血動脈未首先閉塞,這種靜脈阻塞方式會帶來瘺破裂的風(fēng)險。通過動脈入路,過程的成功取決于以下參與我們分級系統(tǒng)的幾個因素:穿支動脈(有=1,無=0),過路動脈(有=1,無=0),分水嶺區(qū)域供血(有=1,無=0),尺寸>3cm (有=1,無=0)。分?jǐn)?shù)越高,意味著預(yù)后越差。最近,隨著Onyx的幫助,經(jīng)靜脈入路栓塞不斷發(fā)展。這一技巧還沒得到大樣本病例評估,其潛在危害還未知。我們限定靜脈入路適用于功能區(qū)的小AVM,細(xì)小的動脈很難超選而引流靜脈容易導(dǎo)管到達(dá)。任何一種栓塞方式的主要風(fēng)險是出血,發(fā)生在部分瘺單元保持不閉。涉及治療的適用癥的關(guān)鍵點是未破裂的AVM。最近兩個前瞻性對照研究(左側(cè)未治療)質(zhì)疑了未破裂AVM的治療收益。當(dāng)前,未破裂AVM大多數(shù)選擇未治療,破裂AVM比未破裂AVM有較高的出血風(fēng)險,選擇治療的適應(yīng)癥在此組更高。然而當(dāng)考慮動靜脈瘺全部閉塞相關(guān)的神經(jīng)功能缺失風(fēng)險較高,我們限定實施AVM的部分治療,處理明確的出血責(zé)任部分。AVM的血管內(nèi)治療是需要介入神經(jīng)放射培訓(xùn)時間最長的干預(yù)措施。
|
|