Hyperperfusion Syndrome after Carotid Stent-Supported Angioplasty in Patients with Autonomic Dysfunction
A 78-year-old male patient visited our hospital due to transient dysarthria and left-sided weakness which persisted for 5 years. He also had hypertension and diabetes mellitus. On arrival at the hospital, his National Institutes of Health Stroke Scale score was 2 with dysarthria and left-sided weakness (MRC grade IV). Brain magnetic resonance (MR) images showed no signs of acute cerebral infarction but brain MR angiography showed high grade stenosis of the proximal right internal carotid artery (ICA). Cerebral angiography performed one month later showed 80% stenosis of the symptomatic right ICA origin () and 55% stenosis of the left ICA origin. CSA was performed on the right side. An intravenous bolus of 5000 IU of heparin was administered. An anticholinergic drug (atropine) was administered before CSA to prevent hyper-parasympathetic function by the baroreceptor-reflex. The CSA procedure was performed in a standard protocol, including the following steps : placement of a 7.2 mm Emboshield NAV6 protection device (Abbott Vascular, Santa Clara, CA, USA), present angioplasty by 7×40 mm Sterling Monorail angioplasty balloon (Boston Scientific Corporation, Maple Grove, MN, USA), and 7-10 mm×40 mm RX Acculink® stent placement (Abbott Vascular, Santa Clara, CA, USA). Blood pressure was monitored and controlled pre- and post-procedurally. The morphological result improved with mild residual stenosis after dilation (). Approximately 10 minutes after the intervention, the patient suddenly showed anosognosia and tried to sit up, developed left-sided weakness (MRC grade III/III), deviation of eye ball position to the right side, and became irritable. The patient had to be restrained because of constant movement, causing his blood pressure to rise up to 197/115 mm Hg. Despite using antihypertensive agents, his blood pressure did not fall below 150/100 mm Hg. In the intensive care unit, calcium channel block was maintained and blood pressure remained stable at 110/75 mm Hg.\nOn a 24-hour follow-up MRI, newly developed restricted diffusion lesions were found in the right ICA (middle and anterior cerebral arteries) territory. The apparent diffusion coefficient in the lesions amounted to a much higher value than that of normal parenchymal tissue, suggesting vasogenic edema ().\nAssessment of the autonomic function test was performed because the patient had a history of diabetes mellitus. In cold pressor test, blood pressure increased by systolic 31 mm Hg and diastolic 22 mm Hg, showing a normal reaction. During the deep-breathing test, the difference between the maximal and minimal heart rate during six successive breaths was less than 10 beats/min indicated abnormal function. The 30/15 ratio was calculated as the ratio of the R-R interval at beat 30 after standing to that at beat 15 (ratio=1.02 as a borderline response). During Valsalva-maneuver testing, the Valsalva ratio for this patient was 1.10 and defined as an abnormal autonomic response ().