両側頸動脈内膜剥離術症例の検討

Bilateral carotid endarterectomy for patients with bilateral carotid artery stenosis

I．はじめに

　脳血管障害における脳梗塞の比率は近年増えており，なかでも頭蓋外頸部動脈病変が増加しているといわれている^14）．この頸部内頸動脈狭窄症に対する頸動脈内膜剥離術（carotid endarterectomy，以下CEAと略す）については，最近のrandomized study，すなわちEuropean Carotid Study Trial（ECST）^4），North American Symp—tomatic Carotid Endarterectomy Trial（NASCET）^17）をはじめ，欧米での大規模な共同研究^{7,13,23-25）}により，70％以上の頸動脈狭窄を有する症候例では，CEA施行群の方が保存的治療群より優れた脳梗塞の予防効果を有することが報告され今後本邦においてもCEAの症例数の増加が予想される．しかしながら，この頸動脈病変が両側性に認められる場合，その手術適応や手術法，周術期管理について問題となることが多い^{1,12,15,20）}．また，本邦において片側CEA症例を100例以上報告している施設の最近の報告でも，両側CEAは上田ら^27）の20例を除くと5-9例^2,8,18,28）と意外に少なく，未だ十分な検討がなされていないのが現状と考えられる．

　そこで今回著者らは，当科で施行した両側CEA症例について，その臨床像，治療成績を検討するとともに，治療上の問題点について文献的考察を加え報告する．

In a couple of recent randomized trials, the benefits of unilateral carotid endarterectomy (CEA) have been reevaluated in symptomatic patients with severe steno-sis. In contrast, the operative indication, procedure, and perioperative management of bilateral CEAs for pa-tients with bilateral carotid artery stenosis are still con-troversial. In this report, we reviewed 7 patients who underwent bilateral CEAs at our institute during the last 10 years, with regard to the clinical feature, angio-graphical findings, operative procedure, surgical results and long-term prognosis.

The patients ranged from 52 to 73 years in age, and included six males and one female. Clinical symptoms were asymptomatic in 1 patient, transient ischemic attack in 2, reversible ischemic neurological deficits in 2, minor completed stroke in 1, and major completed stroke in 1. The angiographical carotid artery stenosis in the dominant side of symptomatic cases was 50% in 3, 70% in 1, 90% in 2, and ulceration in 4 cases. The ste-nosis in the non-dominant side of symptomatic cases was 60% in 1, 70% in 3, 90% in 2, and 4 cases with ulceration. One case among the asymptomatic cases had bilateral 80-90% stenosis. We staged bilateral CEAs, in the dominant side first except in one case among the symptomatic cases and on the more severely stenotic side first in the asymptomatic cases. During CEA, an external shunt was placed in 1 case, but no in-ternal shunt was used in any of the cases. Perioperative complications were found in 2 patients, transient bi-lateral hypoglossal nerve palsy and local hemorrhage in the other case. Totally, all of 7 cases (14 consecutive CEAs) have been performed with satisfactory results. No mortality and no permanent morbidity has resulted. In the follow-up period (mean: 38.3 month), 1 patient was found to have developed cerebral infarction in the ipsilateral carotid artery territory.

From our own small experience and from that in the literature, CEAs for bilateral carotid artery stenosis should be performed in the dominant side first. Then, after a certain period, from 2 to 6 weeks, the CEA should be performed in the non-dominant side.