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(Stroke. 2008;39:3088.)
© 2008 American Heart Association, Inc.

Research Letters

Intraoperative Microemboli and Low Middle Cerebral Artery Blood Flow Velocity Are Additive in Predicting Development of Cerebral Ischemic Events After Carotid Endarterectomy

Kuniaki Ogasawara, MD; Yasunori Suga, MD; Makoto Sasaki, MD; Kohei Chida, MD; Masakazu Kobayashi, MD; Kenji Yoshida, MD; Yasunari Otawara, MD Akira Ogawa, MD

From the Departments of Neurosurgery (K.O., Y.S., K.C., M.K., K.Y., Y.O., A.O.) and Radiology (M.S.), School of Medicine, Iwate Medical University, Morioka, Japan.

Correspondence to Kuniaki Ogasawara, MD, Department of Neurosurgery, School of Medicine, Iwate Medical University, 19-1 Uchimaru, Morioka, Iwate 020-8505, Japan. E-mail kuogasa{at}iwate-med.ac.jp

Background and Purpose— Microemboli generated during dissection of the carotid arteries in patients undergoing carotid endarterectomy result in postoperative cerebral ischemic events. The purpose of this study was to determine whether these events correlate with middle cerebral artery blood flow velocity.

Methods— One hundred sixty-three patients with ipsilateral internal carotid artery stenosis (>70%) underwent carotid endarterectomy under transcranial Doppler monitoring of mean blood flow velocity and microembolic signals in the ipsilateral middle cerebral artery.

Results— Logistic regression analysis of several variables demonstrated that only middle cerebral artery mean blood flow velocity during carotid dissection was significantly associated with new postoperative neurological deficits in patients with microembolic signals during carotid dissection (95% CI, 1.069 to 1.528; P=0.0072). The combination of low middle cerebral artery mean blood flow velocity (28 cm/s) and microembolic signals 10 during carotid dissection resulted in improved specificity and positive predictive value for the development of new postoperative neurological deficits when compared with either criterion used alone.

Conclusions— Intraoperative microemboli and low middle cerebral artery mean blood flow velocity are additive in predicting the development of cerebral ischemic events after carotid endarterectomy.

Key Words: carotid endarterectomy • diffusion-weighted imaging • flow velocity • microemboli • transcranial Doppler ultrasonography