症候性頚動脈狭窄症において総頚動脈限局病変は再発危険因子か

Are Localized Lesions in the Common Carotid Artery a Risk Factor for Recurrence of Ischemic Stroke in Patients with Symptomatic Carotid Artery Stenosis?

Ⅰ．はじめに

　頚動脈狭窄症は，虚血性脳卒中の主要な原因の1つである．近年の内科的治療の発展は著しく¹⁾，無症候性頚動脈狭窄症への外科的治療介入の機会は減少しつつある．しかし，虚血性脳卒中を発症した症候性頚動脈狭窄症は，90日以内の虚血性脳卒中再発が他の病型の5倍とも報告されており^11,12)，適切な内科的治療に加え，積極的に外科的治療介入を必要とする症例が存在する．

　症候性頚動脈狭窄症における虚血性脳卒中再発危険因子としては，脳梗塞発症例^7,20)，高度狭窄病変¹⁷⁾，プラークの炎症や脆弱性を有する病変¹³⁾などの報告がみられる．われわれは，症候性頚動脈狭窄症のうち，内科的治療抵抗性に脳梗塞再発を来した総頚動脈限局病変の2症例を経験した．

　これまで総頚動脈狭窄症に関しては，その近位部（入口部）病変を中心とした治療に関する報告^3,10,18,22)が散見されるのみであり，再発に関する検討の報告はみられない．頚動脈分岐部を含む内頚動脈病変に関しては，無症候性および症候性ともに多くのランダム化比較試験が存在し，治療ガイドラインも確立されているが，総頚動脈限局病変に関してはほとんど明記されていない．

　今回われわれは，症候性頚動脈狭窄症において，総頚動脈限局病変と頚動脈分岐部を含む内頚動脈病変とを分け，総頚動脈限局病変が虚血性脳卒中再発危険因子であるかを明らかにすることを目的とし，後方視的に検討を行った．

　BACKGROUND and PURPOSE:Various studies have addressed risk factors for recurrence of ischemic stroke in patients with symptomatic carotid artery stenosis. However, no investigations have compared common localized carotid artery lesions and internal carotid artery lesions, including carotid bifurcation. This retrospective study investigated risk factors for ischemic stroke recurrence in patients with symptomatic carotid artery stenosis, including a comparison of lesion sites.

　METHODS:Of 61 consecutive patients admitted to the authors’ hospital due to a diagnosis of symptomatic carotid artery stenosis between April 2015 and March 2018, data from 59 were retrospectively reviewed（2 patients diagnosed with arterial dissection were excluded). The primary end point was recurrence of ischemic stroke caused by symptomatic carotid artery stenosis, the cause of the first event. Patients were censored at the time of surgical intervention;events occurring during and after surgical intervention were not included. In the ischemic stroke recurrence and non-recurrence groups, each item was analyzed using the Kaplan-Meier method, and a log-rank test was performed with a significance level set to 5%.

　RESULTS:Ischemic stroke recurrence before surgical intervention was observed in 5（8.5%）patients. In comparing the recurrence and non-recurrence groups, a significant difference was observed in age（p＝0.027）and lesion site（p ＜0.001).

　CONCLUSION:A localized lesion in the carotid artery was a risk factor for recurrence of ischemic stroke in patients with symptomatic carotid artery stenosis. For individuals with symptomatic localized lesions in the common carotid artery, surgical intervention should be considered-in addition to medical treatment-regardless of the degree of stenosis.