Sami Al Kasab, MD
With the increased imaging of the head and neck vasculature as part routine stroke/TIA workup, diagnosis of intraluminal thrombus (ILT) has become more common. The presence of ILT in the cervico-cephalic vasculature in patients with TIA or stroke poses a diagnostic and therapeutic challenge. In this study, Singh et al. report the clinical and imaging manifestation of ILT and provide recommendations on therapeutic options. The study was conducted at the University of Calgary. Patients with suspected TIA or stroke between April 2015 and September 2017 were included in these analyses. Diagnosis of ILT was made by CTA of the head and neck performed routinely on admission, which was evaluated by a neuroradiologist, once the diagnosis of ILT was made, it was confirmed by a second neuroradioloigst.
A total of 3750 patients were evaluated during the study period; ILT was identified in 61 patients (1.6%). Median age was 67 years (IQR, 56-73); 40 (65.6%) patients were men. Patients with ILT had high prevalence of hypertension, smoking and dyslipidemia (47.5%, 44.3%, and 41% respectively). The most common presentation was ischemic stroke (80.3%), and most strokes were mild with median NIHSS of 2 (IQR, 1-4). The most common location of ILT was extracranial internal carotid artery (65.6%), followed by extracranial vertebral artery (11.2%). The most common cause of ILT was atherosclerosis in the affected artery (82 %) manifested by ulcerated plaque with or without luminal stenosis. Ulcerated plaque was identified in 6.6% of patients only. 51/61 (83.6%) were found to have ≥50% underlying stenosis, arterial dissection was identified in 6.6% of cases and 1 patient (1.6%) had cardio-embolic etiology.
Most patients were treated with a combination of intravenous heparin and 1 antiplatelet agent (93.4%). Less common regiments included anticoagulation alone or antiplatelet alone. On follow up, 6.6% of patients had a recurrent TIA/stroke during their hospital stay. 96.7% of patients had follow up imaging at a median time of 6 days (IQR, 4-10). ILT was unchanged in 25.4% of cases, partially resolved in 47.5% and completely resolved in 27.1% of cases. Stenosis > 50% was identified in 71.2% of cases. Of the 30 patients with > 50% residual stenosis of the extracranial ICA, 24 patients underwent carotid revascularization with either stenting (9) or endarterectomy (15). Carotid revascularization occurred in the first 2 weeks of symptoms onset with median interval time from symptoms to revascularization of 9 days, there were no reported complications.
In this study, the authors report the prevalence, imaging features and therapeutic approaches to ILT. The study shows a prevalence of 1.6% of ILT, with the most common location being the cervical ICA. Most common treatment modality was the combination of anticoagulation and monoplatelet therapy with resultant partial or complete resolution in approximately 75% of the ILTs. Follow up imaging was performed on most patients, and patients with underlying residual stenosis of > 50% underwent revascularization with CAS or CEA with no reported peri-procedural complications, even in the presence of ILT prior to the procedure (33.3% of CASs and 13.3% of CEAs). Follow up imaging showed reduction in the degree of stenosis from > 50% to < 50% in 14% of cases.
Data from this study provide important information on a rare but challenging clinical scenario. Based on evidence from this prospective study, as well as previous case series reporting clinical and imaging data, the best approach to patients with TIA/stroke and ILT in the cervico-cephalic vasculature is with medical management with anticoagulation with or without antiplatelet with follow up imaging to evaluate the underlying degree of stenosis following complete or partial resolution of the thrombus.
