Relationship between histologic features and outcomes of carotid revascularization for radiation-induced stenosis.
OBJECTIVE
This study aimed to elucidate the relationships between preoperative carotid imaging results, histologic characteristics, and surgical treatment outcomes of radiation-induced carotid stenosis (RICS), using control subjects without RICS for comparison.


METHODS
We retrospectively reviewed records of 17 patients who underwent carotid revascularization for 22 instances of RICS, including 10 cases of carotid artery stenting (CAS), 11 cases of carotid endarterectomy (CEA), and 1 case of CEA with retrograde CAS, between July 2004 and April 2013. The controls were 475 patients with no history of radiation therapy who underwent carotid revascularization in a similar period. Preoperative magnetic resonance imaging (MRI), ultrasonography (US), and computed tomography angiography results were correlated with outcomes of histologic analysis of CEA specimens. End points included ipsilateral and contralateral stroke, myocardial infarction, restenosis, in-stent thrombosis, and target lesion revascularization.


RESULTS
Vulnerable plaques on carotid MRI (86% vs 64.2%; P = .010) and mobile (27% vs 8.0%; P = .008) and ulcerative (50% vs 15.8%; P < .001) plaques on US were more frequent in the RICS group. All revascularization procedures were successful, and no occlusion occurred. Adverse events in the CAS group, including one minor stroke and one transient ischemic attack within 30 days as well as five ipsilateral neurologic events after 30 days, including three minor strokes and two transient ischemic attacks, were significantly more frequent than in the CEA group. All three cases of late ipsilateral stroke displayed vulnerable plaque on preoperative MRI and late in-stent thrombosis or restenosis on US.


CONCLUSIONS
Our radiologic and histologic analyses revealed that advanced RICS is often accompanied by formation of vulnerable plaque. CEA can prevent undesirable late outcomes in such cases.
Department of Neurosurgery, National Cerebral and Cardiovascular Center, Suita, Japan; Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Noritaka
N
Sano
Department of Neurosurgery, National Cerebral and Cardiovascular Center, Suita, Japan.
Tetsu
T
Satow
Department of Neurosurgery, National Cerebral and Cardiovascular Center, Suita, Japan.
Daisuke
D
Maruyama
Department of Neurosurgery, National Cerebral and Cardiovascular Center, Suita, Japan.
Hiroharu
H
Kataoka
Department of Neurosurgery, National Cerebral and Cardiovascular Center, Suita, Japan; Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan.
Ken-ichi
K
Morita
Department of Pathology, National Cerebral and Cardiovascular Center, Suita, Japan.
Hatsue
H
Ishibashi-Ueda
Department of Neurosurgery, National Cerebral and Cardiovascular Center, Suita, Japan; Department of Neurosurgery, Graduate School of Medical Sciences Kyushu University, Fukuoka. Electronic address: kiihara@ns.med.kyushu-u.ac.jp.
Koji
K
Iihara
D000368:Aged; D000369:Aged, 80 and over; D019917:Blood Vessel Prosthesis Implantation; D016893:Carotid Stenosis / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery*; D003251:Constriction, Pathologic; D016894:Endarterectomy, Carotid; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011832:Radiation Injuries / Q000150:complications / Q000175:diagnosis*; D012189:Retrospective Studies; D015607:Stents; D016896:Treatment Outcome