A Case of Fatal Cerebral Hyperperfusion Syndrome Following Carotid Artery Stenting: Practices and Lessons Learned

Cerebral hyperperfusion syndrome (CHS) is a clinical syndrome characterized by headaches, neurological deficits, and seizures caused by intracerebral edema or hemorrhage that follows a revascularization procedure. It is a relatively rare, potentially preventable condition that may lead to devastating clinical consequences. The underlying mechanism is still not fully understood. However, dysregulation of the cerebral vascular system in the setting of increased cerebral blood flow has commonly been accepted as a pathophysiological core of the disease. Its clinical characteristics may vary significantly in different patients. Although there are currently no specific guidelines for managing CHS, identification of patients at risk, early recognition, and aggressive treatment of hypertension are critically important. A 79-year-old woman with a history of arterial hypertension, diabetes, dyslipedmia, and ischemic heart disease under partial medical control was brought to the Emergency Room by her family due to facial assymmetry, mild weakness in the left arm, and dysarthria, which had appeared 3 days earlier. She had a National Institutes of Health Stroke Score (NIHSS) of 4 on neurological examination. Head CT scan showed chronic bilateral periventricular lesions, with no evidence of any acute/subacute ischemic changes (Alberta Stroke Program Early CT score [ASPECTS] of 10). CT angiography (CTA) showed near-total occlusion of the right internal carotid artery (ICA) in the proximal cervical segment with sluggish filiform antegrade flow secondary to a long, predominantly soft, atherothrombotic lesion. There was retrograde filling of the distal ICA through the ophthalmic artery, and a patent right middle cerebral artery (MCA). CT scan was complemented by an abbreviated diffusion-weighted magnetic resonance imaging (MRI-DWI) study revealing a subacute subcortical watershed infarct in the right frontal lobe. Given the high chance for infarction growth due to the high-grade proximal stenosis and availability of only a collateral pathway through the ophthalmic artery, stroke and interventional team members recognized the clear need for endovascular carotid artery revascularization. The patient received a loading dose of clopidogrel, and an adequate antiplatelet response was confirmed using the VerifyNow system. The patient underwent an uneventful stent-assisted right ICA angioplasty. One hour after the intervention, she developed a hypertensive crisis treated with labetalol. After cessation of sedation, the patient remained unresponsive and developed bilateral mydriasis. Urgent head CT confirmed massive right-side intraparenchymal bleeding with extension into the ventricular system and subarachnoid space. The patient was not a candidate for external ventricular drain (EVD) placement. Unfortunately, she died shortly afterwards. This chapter focuses on the pathophysiology, presentation, risk factors, prevention, and management of cerebral hyperperfusion syndrome in patients undergoing carotid artery stenting.