Abstract 405: Severe “Crescendo” Recurrent TIAs In Moderate Carotid Artery Stenosis Without High‐risk Features
Authors: Palegar T. , Mahat B. C. , Ahmad M. J. , Miao C. , Almast A. , Pillai B. , Doheim M. , Nogueira R. G. , Al-Bayati A. R. 
Published: January 2025

Introduction
Symptomatic internal carotid artery stenosis (ICA) is defined as focal neurologic deficits ipsilateral to carotid artery pathology presenting as a transient ischemic attack (TIA) or stroke, frequently seen with moderate to severe (50‐99%) ICA stenosis. Stroke warning syndrome (SWS) is a rare form of TIA presenting as recurrent, or “crescendo”, TIAs with a high stroke risk typically seen in the absence of cortical signs and related to small vessel disease or hypoperfusion. Our case describes a patient with recurrent stereotypic crescendo TIAs with near complete cortical left middle cerebral artery (MCA) syndrome secondary to moderate (50‐69%) ICA stenosis without high‐risk features (intraplaque hemorrhage, large lipid‐rich necrotic core, thin or ruptured fibrous cap), with complete resolution of symptoms after carotid endarterectomy (CEA).

Case
We report a 66‐year‐old female smoker without significant medical history presenting with complete left MCA syndrome‐ left gaze, dysarthria, complete expressive aphasia, and right sided hemiplegia, with last known well approximately 12 hours prior to presentation. CT angiography (CTA) of the head and neck demonstrated an estimated 60‐65% stenosis of the left carotid bifurcation with mixed hard and soft plaque without ulceration or unstable thrombi; no intracranial occlusions were noted. The patient had spontaneous resolution of symptoms with NIHSS 0, so thrombolysis was deferred. Within a few hours of presentation, she experienced three additional episodes of varying severity, each lasting approximately five minutes, with complete resolution between episodes. This raised concern for an unstable plaque; therefore, she was started on aspirin and intravenous (IV) heparin drip with plan for urgent carotid revascularization. After heparin was paused pre‐operatively, she had two additional witnessed similar events lasting less than ten minutes each. Following endarterectomy, she had complete resolution of symptoms without recurrence. MRI brain showed no infarction, additional stroke workup was otherwise unrevealing, and she was discharged on daily aspirin. On three‐month post‐operative follow up, the patient reported no further symptom recurrence.

Discussion
The incidence of TIAs presenting as SWS is as high as 4.5%, yet there are no clear guidelines for SWS management. SWS is typically observed in small vessel pathology and hypoperfusion, and less commonly in carotid artery pathology. Our patient presented with episodes consistent with cortical L MCA symptoms, typically seen with a proximal MCA occlusion. However, the frequency of these episodes exceeded what is expected from moderate carotid artery stenosis, especially in the absence of many known high‐risk plaque markers. While stereotypic symptoms raise concern for alternative diagnosis, such as seizures, the cessation of symptoms with IV heparin and subsequent complete resolution following revascularization confirmed the diagnosis of symptomatic carotid disease. In symptomatic moderate ICA stenosis, the benefit of urgent carotid revascularization over medical treatment of anti‐thrombotic or stroke prevention is modest, with the greatest effect observed in cases with severe stenosis. In patients with crescendo TIA with moderate ICA stenosis, even without high‐risk features, carotid revascularization may be beneficial. While there is no strong evidence supporting anticoagulation over anti‐platelet therapy in symptomatic ICA stenosis, anticoagulation may be considered in patients presenting with SWS.