Symptomatic Internal Carotid Artery Stenosis with Intraluminal Thrombus: Dual Antiplatelets with Proven Effect, Thrombus Clearing, and a Delayed Safe Stent Angioplasty Procedure

Intraluminal carotid artery thrombus (or carotid free-floating thrombus), defined as a blood clot attached to the arterial wall with surrounding blood flow at its distal component, is considered an infrequent finding in patients presenting with a transient ischemic attack or ischemic stroke. It can be a focal process limited to the cervical internal carotid artery (ICA) or a more extensive condition that involves both the extracranial and intracranial ICA. Intraluminal thrombus can be found more commonly in the presence of carotid stenosis but also without stenosis. When identified in patients without underlying carotid stenosis, it is often associated with a hypercoagulable state. In patients with underlying carotid stenosis, intraluminal thrombus incidence is correlated with the severity of the atherosclerotic disease. Intraluminal thrombus is associated with an increased risk of stroke. The presence of thrombus doubles the risk of stroke in patients undergoing carotid endarterectomy and triples the risk for patients treated conservatively. Consensus is lacking among stroke experts on whether patients with thrombus should be anticoagulated in the acute phase, receive single antiplatelet or dual antiplatelet agents, or whether antiplatelet and anticoagulant regimens should be combined. The duration of any combined or anticoagulant treatment, the recommended revascularization procedure, and the timing of the procedure also remain a matter of debate. A 75-year-old male patient with a past medical history of arterial hypertension and ischemic heart disease under treatment with aspirin and angiotensin-converting enzyme (ACE) inhibitors was admitted to a local hospital due to a 15-minute episode of mild right-sided hemiparesis. His clinical and neurological examination was normal upon admission, and noncontrast cranial CT was unremarkable. However, CT angiography revealed severe stenosis of the left ICA bulb caused by a focal eccentric soft atherothrombotic lesion with associated intraluminal thrombus. The intracranial vasculature was fully patent. Treatment with clopidogrel and high-dose atorvastatin was started, and the patient was referred to our center for carotid artery stenting (CAS) 3 days later. He was asymptomatic upon admission. Antiplatelet therapy response assessment using VerifyNow (Accriva) revealed nonresponsiveness to clopidogrel. Diagnostic angiography confirmed moderate-to-severe stenosis of the left ICA bulb with an associated clot on the plaque’s surface. Given the increased procedural risks associated with the intraluminal clot and lack of response to clopidogrel, we decided to switch from clopidogrel to ticagrelor and postpone the procedure by 1 week so that for thrombus clearing. Treatment with ticagrelor was initiated, and the adequate antiplatelet response was confirmed. The patient was discharged on dual antiplatelet therapy (DAPT) with aspirin and ticagrelor and was readmitted for CAS 7 days later. Repeat angiography before the CAS confirmed complete clearing of the thrombus. The patient underwent a successful transfemoral stent-assisted angioplasty of the proximal left ICA. His clinical course was unremarkable, and he was discharged asymptomatic on DAPT. This chapter describes a case of symptomatic ICA stenosis with associated intraluminal thrombus, focusing on available therapeutic options. In patients who do not require an urgent intracranial thrombectomy, our preferred strategy is dual antiplatelet therapy with a proven antiplatelet response and delayed CAS. We describe our standard procedure and present a glimpse of current controversies and ongoing debates.