收集2009年3月至2018年3月在浙江省人民医院血管外科接受治疗的19例分叉部狭窄的腹主动脉瘤患者，术前多经腹主动脉超声筛查后进一步行主动脉CT血管造影检查确诊。所有患者均为男性，年龄42~89岁，平均年龄为(62.3±0.8)岁；体检发现腹主动脉瘤13例(68.4 %)，以腹部搏动性肿块就诊4例(21.1 %)，表现为急性腹部疼痛2例(5.3 %)；合并高血压16例(84.2 %)、糖尿病8例(42.1 %)、冠心病3例(15.8 %)；有吸烟史5例(26.3 %)。入组患者动脉瘤最大直径为41.2~87.2 mm，平均为(60.6±1.2) mm，靠近髂总动脉分叉点的血管直径为10~18 mm( 图 1 )；近端瘤颈15~35 mm，平均为(21.3±1.7)mm；困难瘤颈3例(15.8 %)。

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患者选用全身麻醉或局部麻醉。术前静脉推注30~50 mg肝素。手术步骤：①一侧切口解剖股总动脉，穿刺对侧股总动脉并置入8F鞘管，送入导管至对侧股总动脉并引出体外；②Aegis-B分支导丝从对侧股动脉引出体外, 同侧股总动脉送入超硬导丝；③Aegis-B支架沿超硬导丝推入主动脉于肾动脉开口附近，预释放Aegis-B支架使对侧分支及导丝脱离远外管，向下拉直支架至Aegis-B的分叉点于主动脉分叉位置，释放裸段、主体、对侧同侧分支；④造影观察有无内漏、肾动脉的显影、髂内动脉的保留情况和下肢动脉的血供等；⑤同侧股动脉缝合，对侧股动脉穿刺点封堵器闭合( 图 2 )。

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患者于术后15 d及3、6、18、24、48个月行主动脉CT血管造影，观察支架相关性内漏、支架移位情况及有无下肢缺血。

采用SPSS 18.0软件进行数据统计，正态分布的计量资料以均数±标准差( s )表示，非正态分布的计量资料以中位数表示。

所有患者均成功完成手术，平均手术时间为(70.0±2.3)min，术中无动脉瘤破裂及中转开腹手术。所有患者至少保留一侧髂内动脉。Ⅰ型内漏2例，均为近端内漏且发生于困难瘤颈病例，球囊贴壁扩张近端锚定区后1例内漏消失，1例经球囊反复扩张后仍存在少量内漏，测量近端锚定区超过15 mm，未放置cuff(主动脉延伸覆膜血管内支架)，术后15 d内漏消失。覆盖单侧髂内后引起Ⅱ型轻微内漏1例，为非瘤颈困难病例，无特殊处理，术后复查内漏消失。3例患者发生术中支架相关并发症：输送系统退出困难2例，其中1例反复尝试后成功退出，另1例退出超硬导丝后轻柔退出；入路困难1例，予球囊扩张髂外动脉后成功导入。8例患者术后2周内出现不同程度支架源性发热，体温最高为38.7 ℃。

19例患者随访9~48个月，中位随访时间为27个月。随访期间内无支架移位，无下肢缺血。术后15 d复查，术中发现的2例Ⅰ型内漏、1例Ⅱ型内漏均消失。随访期间发生Ⅰ型内漏1例，CT血管造影提示对比剂少量外溢，移植物未见明显移位，患者无临床症状，继续随访中。

EVAR是治疗腹主动脉瘤里程碑式的手术革新，具有微创性和极低的围手术期并发症发生率。腹主动脉覆膜支架分为一体式和分体式两种，目前主流的腹主动脉覆膜支架为分体式，但其仍不能解决远期支架向下移位，以及分叉部狭窄腹主动脉瘤中双裤腿挤压这两个难题。前者会导致继发的Ⅰ型内漏、动脉瘤继续增大及动脉瘤破裂，后者会导致下肢严重的血流动力学障碍甚至缺血 。针对前者，各大厂家通过延长近端锚定区、增加近端覆膜倒钩等方法，在一定程度上缓解了支架远期向下移位，但支架远端移位的并发症仍无法完全根除。而针对后者，由于动脉瘤的解剖原因，目前无法通过改良分体式支架来解决双腿挤压的难题

对于少见的分叉部狭窄腹主动脉瘤，由于分体式支架的分叉部位在动脉瘤腔，采用分体式支架会导致两条分支受血管挤压而无法完全展开，造成肢体缺血；而一体式支架根据解剖开发，其分叉部位与人体主髂动脉分叉解剖位置重合，因此对于未累及腹主动脉分叉部位并且分叉部位血管直径不超过18 mm的腹主动脉瘤，放置一体式支架应该是一个更好的选择。

另外，相对于分体式支架，一体式支架有以下优势：①分体式覆膜支架须对接对侧短腿，易发生覆膜连接不良引起的Ⅲ型内漏，而一体式覆膜支架无须对接，避免了Ⅲ型内漏的发生；②分体式支架仅依靠主体支架近端与瘤颈的锚定来固定支架本身，而一体式支架的分叉部位位于腹主动脉分叉处，支架近端及瘤颈锚定形成“两点”固定，植入后长期稳定性更好；③分体式支架操作时间长，而一体式支架对侧导丝已提前放置好且不需要对接对侧短腿，操作时间缩短。

一体式覆膜支架是根据EVAR新概念“解剖固定” 为理论依据研制，即将一体式覆膜支架在腹主动脉分叉处上方释放，使其骑跨在分叉上，恰好符合主髂动脉的解剖特点。Jordan等 和Harlin等 的临床试验分别对78例和44例使用Powerlink一体式支架的腹主动脉瘤患者进行平均24个月的随访，均没有发现植入物移位。本文资料采用的Aegis-B支架是与Powerlink支架同期研发的腹主动脉覆膜支架系统，19例患者随防中未发现支架移位导致的隔绝不完全的并发症，同时亦未发现支架植入后导致下肢缺血并发症。结果提示一体式支架植入后远期相对不易移位，同时推测一体式覆膜支架系统可解决分叉部狭窄腹主动脉瘤患者易双腿挤压的难题。

临床使用一体式支架需注意以下几点：①控制血压，特别是在支架释放时防止高血流冲击导致支架移位，定位稳定是关键；②释放支架后，撤出导送系统，通过狭窄段时注意防止扯拉引起支架破损、移位；③一体式支架对于主体支架的长度要求更为精确，主体支架过短不能完全隔离瘤体而需要另外增加近端延伸支架，主体支架过长则易封堵肾动脉开口，因此术前需进行影像学的准确评估，必要时定制支架 ；④一体式覆膜支架术后仍易发生Ⅰ型内漏，即支架两端漏，以上端漏更常见 。如锚定区较短，有必要直接放置Cuff。如果覆膜支架有足够的锚定区距离(≥15 mm)，内漏可能为支架未完全贴壁所致，植入后随支架的扩张，内漏可以消失，无须球囊扩张或放置Cuff 。本文资料中2例患者出现Ⅰ型内漏，均为近端内漏且发生于困难瘤颈病例，由于瘤颈锚定区较长，未放置Cuff，术后15 d内漏消失。

EVAR因手术微创、患者出血少、术后恢复快等优势，已逐渐成为腹主动脉瘤的主要治疗手段。EVAR运用应根据腹主动脉瘤的形态学指标选择适合的支架。根据目前随访数据，我们认为腹主动脉瘤分叉部位血管直径不超过18 mm时，一体式覆膜支架是比较理想的方案。

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