頸動脈血栓内膜摘除術術中に施行したBalloon Dilatation後の血栓内膜の肉眼的，病理組織学的検討

Macroscopic and pathohistological investigation of endarterial plaque after intraoperative balloon dilatation of the carotid artery during carotid endarterectomy

I．はじめに

　頭蓋外頸動脈の狭窄性病変に対する血栓内膜摘除術（Carotid Endarterectomy，以下CEA）は欧米でのrandomized study等の結果，70％以上狭窄のsymptomatic例，60％以上の狭窄の認められるasymptomatic例に於いて本手術の有効性が認められ，積極的に手術が行われるようになってきた．一方，最近の血管内手術法の普及，カテーテル等材質の進歩，高解像度DSAの導入等に伴い，頸動脈病変に対してもpercutaneous transluminalballoon angioplasty（PTA）が行われるようになりつつある．確かに低侵襲ではあるが未だこの術式の有効性，安全性の確立には至っておらず，再狭窄の問題，血栓遊離による脳塞栓の可能性も危惧されている^{2,5,11,13,21）}．また，頸動脈を含めPTAによる血管拡張の機序，血管壁の変化等について，実際の施行時や施行後の病理組織で検討した報告は少なく^4,15），適応についても確立されていないのが現状である．今回われわれはCEAの術中に頸動脈狭窄部のballoon dilatationを行い，その後摘出した．血栓内膜の肉眼的，病理組織学的検討から，PTAの有効性，危険性等について考察を加え報告する．

Twelve patients associated with stenosis of the extracranial carotid artery underwent intraluminal bal-loon dilatation during carotid endarterectomy (CEA). There were 11 men and 1 woman, and age rangedfrom 56 to 73 years old. The rate of stenosis, shown by angiography, in each patient was from 60 to 85%in width. After securing carotid blood flow by a T-shaped shunt tube, a balloon catheter was inserted fromthe exposed common carotid artery into the internal carotid artery. The balloon was inflated three or fourtimes with 2.5-3.5 atm. for 30-40 seconds. Immediately after balloon dilatation, endoscopic investigationwas performed (Wolf; hard type emloscope, 2.7mm diameter). Then CEA was performed using the usualprocedure. The removed endarterial plaque was investigated pathohistologically.

In macroscopic and encloscopic findings, there were 6 patients with mural thrombosis, 4 patients withlaceration of the intima, and one patient with outflow of atheroma from the intima. Only 3 patients had in-crease in lumen after balloon dilatation. In pathohistological appearance, all patients had a moderate de-gree of fibrosis, calcification, and atheroma in the cross section of the plaque. Ten patients had intramuralhemorrhage.

Three typical patients were revealed by the use of angiographical, ultrasonographical, endoscopic, andpathohistological presentation. Case 10 showed laceration of the intima by balloon dilatation, and had mod-erate increase in lumen size macroscopically and endoscopically. There were moderate cases of fibrosis,calcification, atheroma, and intramural hemorrhage. Dilatation of the lumen seemed to be accomplished bya decrease in thickness of the atheroma and intramural hemorrhage. Case 8 demonstrated an increase in lu-men size, but also laceration of the intima and outflow of atheroma from the arterial wall. There weremuch atheroma and large intramural hemorrhage in the intima, which might become a source of enbolism.Case 7 revealed no laceration of the intima and no increase in lumen size. Preoperative ultrasonography