Postoperative cortical neural loss associated with cerebral hyperperfusion and cognitive impairment after carotid endarterectomy: 123I-iomazenil SPECT study.
OBJECTIVE
Although cerebral hyperperfusion after carotid endarterectomy (CEA) often impairs cognitive function, MRI does not always demonstrate structural brain damage associated with postoperative cognitive impairment. The purpose of the present study was to determine whether postoperative cortical neural loss, which can be detected by (123)I-iomazenil single-photon emission CT, is associated with cerebral hyperperfusion after CEA and whether it correlates with postoperative cognitive impairment.


METHODS
In 60 patients undergoing CEA for ipsilateral internal carotid artery stenosis (>70%), cerebral blood flow was measured using N-isopropyl-p-[(123)I]-iodoamphetamine single-photon emission CT before and immediately after CEA and on the third postoperative day. The distribution of benzodiazepine receptor binding potential in the cerebral cortex was assessed using (123)I-iomazenil single-photon emission CT before and 1 month after surgery and was analyzed using 3-dimensional stereotactic surface projection. Neuropsychological testing was also performed preoperatively and at the first postoperative month.


RESULTS
Post-CEA hyperperfusion and postoperative cognitive impairment were observed in 9 patients (15%) and 8 patients (13%), respectively. Post-CEA hyperperfusion was significantly associated with postoperative hemispheric reduction of benzodiazepine receptor binding potential (95% CIs, 2.765 to 148.804; P=0.0031). Post-CEA hyperperfusion (95% CIs, 1.183 to 229.447; P=0.0370) and postoperative hemispheric reduction of benzodiazepine receptor binding potential (95% CIs, 1.003 to 77.381; P=0.0496) were also significantly associated with postoperative cognitive impairment.


CONCLUSIONS
Cerebral hyperperfusion after CEA results in postoperative cortical neural loss that correlates with postoperative cognitive impairment.
Chida
Kohei
K
Department of Neurosurgery, School of Medicine, Iwate Medical University, Morioka, Iwate, Japan.
Ogasawara
Kuniaki
K
Suga
Yasunori
Y
Saito
Hideo
H
Kobayashi
Masakazu
M
Yoshida
Kenji
K
Otawara
Yasunari
Y
Ogawa
Akira
A
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016893:Carotid Stenosis / Q000601:surgery; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000473:pathology*; D002560:Cerebrovascular Circulation; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging / Q000473:pathology* / Q000523:psychology*; D003072:Cognition Disorders / Q000000981:diagnostic imaging / Q000473:pathology* / Q000523:psychology*; D016894:Endarterectomy, Carotid; D005260:Female; D005442:Flumazenil / Q000031:analogs & derivatives; D006801:Humans; D020367:Iofetamine; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000473:pathology*; D009483:Neuropsychological Tests; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000473:pathology* / Q000523:psychology*; D019275:Radiopharmaceuticals; D013238:Stereotaxic Techniques; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
D019275:Radiopharmaceuticals; D005442:Flumazenil; C063038:iomazenil; D020367:Iofetamine