PO158 | A RARE CASE OF ISCHEMIC STROKE: CAROTID WEBS

C. Mazzei, I. Costanzo, D. Fumarulo, S. Bernardi, G. Trinchera, M. Littera, M. Mazzetti, C. Tamburini | Medicina Interna Interdisciplinare, A.O.U. Careggi, Firenze, Italy

Background. A carotid web (CaWeb) is a rare, atypical variant of fibromuscular dysplasia, characterized by a fibrous intimal flap of the carotid bulb and projecting into the arterial lumen, which can cause altered blood flow, stasis, and thereby promoting thrombogenesis. Latest studies documented strong associations between CaWebs and recurrent TIA or severe strokes of unknown etiology, with a prevalence between young with few traditional cardiovascular risk factors. The gold standard imaging for CaWeb diagnosis is currently computed tomography angiography (CTA), followed by duplex ultrasound (DUS) and magnetic resonance angiography (MRA). While antiplatelet therapy or anticoagulation used to be the cornerstone of management, medical therapy alone has been found to be insufficient for stroke prevention in symptomatic patients. Definitive intervention includes carotid artery stenting or carotid endarterectomy (CEA); both have demonstrated excellent safety and efficacy.
Case report. A 63-year-old woman with history of hypertension and a previous right atrial myxoma, treated 2-years prior with mass removal surgery, shows up for sudden symptoms of left facial paresthesia, right retrobulbar pain, clumsiness in the upper limbs and confusion. The CT cranial scan showed an ischemic right area cortico-subcortical temporo-parietal; the CT angiography and MRI confirmed an occlusion of the right middle cerebral artery’s M2 branch. As a collateral finding on CT angiogram, an opacification defect was reported at right carotid bulbs, suspicious for CaWeb. The ischemic event was classified as minor stroke (NHISS=3) therefore dual antiplatelet therapy was started. In view of the angiographic finding, a DUS of supre-aortic trunks was performed, which confirmed the suspect of carotid web. Meanwhile, other causes of stroke were ruled out by transcranial echocolordoppler which excluded the possibility of a patent foramen ovale (PFO) and an extensive electrocardiographic study excluded arrhythmic events. Lastly a transthoracic echocardiogram and the subsequent transesophageal echocolordoppler were performed, which reported the presence of mobile material at the left atrial appendage, of doubtful interpretation between myxoma recurrence or thrombotic material adhered to the Teflon residues left from the myxoma operation as a complication of the procedure. Given the new findings, and since a cardio-embolic stroke could not be ruled out at that point, warfarin therapy was promptly undertaken, and the patient was transferred to a surgical setting for subsequent removal of the mass and histological examination.
Conclusions. This clinical case confronted us with two possible causes of ischemic stroke, both possible, but which were ultimately given as large-vessel cardio-embolic stroke, considering the higher probability associated. However, the possibility of an event related to CaWeb, even if rare, shouldn’t completely be ruled out. The prevalence in patients with ischemic stroke is around 1-1,2%, however in patients with cryptogenic stroke, especially in cases with no other clear risk factors, the prevalence of CaWeb is markedly higher. One case-control study identified CaWeb to be present in 9,4% of patients under age 60 with cryptogenic stroke. Carotid webs should always be excluded in all cases of cryptogenic ischemic events, especially in young patients without relevant risk factors, even if the diagnosis remains one of exclusion.