[Two cases of cervical carotid artery stenosis with high risk post-operative hyperperfusion treated with dexmedetomidine after carotid endarterectomy].

Dexmedetomidine is a central alpha2 adrenoceptor agonist recently shown to be a safe and acceptable sedative agent for patients requiring sedation after brain surgery. We report two patients successfully treated by carotid endarterectomy (CEA) with postoperative management under dexmedetomidine anesthesia for transient ischemic attack (TIA) resulting from severe stenosis of the internal carotid artery (ICA). Case 1: A 75-year-old man was admitted to our hospital with aphasia and weakness of the right side of his body. Although no evidence of acute cerebral infarction was obtained on magnetic resonance imaging (MRI)/diffusion-weighted image (DWI), MR angiography (MRA) revealed severe stenosis of the left cervical ICA. (123)I-IMP-single photon emission tomography (SPECT) and transcranial Doppler (TCD) revealed marked reduction of cerebral blood flow in the left cerebral hemisphere. Although CEA induced hyperperfusion, aggressive control of blood pressure under dexmedetomidine anesthesia enabled effective management of the resulting hyperperfusion syndrome. The patient was discharged without neurological deficits. Case 2: A 68-year-old man was admitted to our hospital with amaurosis fugax and numbness of the right side of his body. Although no evidence of acute cerebral infarction was obtained on MRI/DWI, MRA disclosed severe stenosis of the left cervical ICA. (123)I-IMP-SPECT revealed extremely low perfusion and disturbance of vascular reactivity in the territory of the left ICA. Although conservative therapy was performed, crescendo TIA was noted. Revascularization using CEA was therefore performed. After surgery, hyperperfusion was observed in the same fashion as in case 1, and again aggressive control of blood pressure under dexmedetomidine anesthesia enabled effective management of the resulting hyperperfusion syndrome. The patient was discharged 1 month postoperatively without neurological deficits. Dexmedetomidine is a safe and acceptable sedative drugs preventing hyperperfusion syndrome after CEA.