The standard of care for patients with symptomatic, severe carotid artery stenosis includes carotid endarterectomy (CEA) plus best medical therapy. A rare cause of this etiology is acute thrombus within the internal carotid artery, referred to as Free-Floating Thrombus (FFT). This pathology is reported to have unstable plaque characteristics and an incidence rate of 0.4-1.5%. Given its rarity there remains a significant gap in understanding of the management of this condition.
A retrospective review of patients in a prospectively collected database was conducted on all patients who underwent CEA for symptomatic carotid artery stenosis at a single institution between 2010 and 2020. Patients were identified after radiographic review of CT angiography at the time of diagnosis as having a FFT. Primary outcomes such as delay to procedure, stroke rates, and other complications, as well as rates of hospital transfers, were measured and compared between groups.
During the study period, 802 CEA were performed, of which, 45 patients were identified to have FFT. Patients in the FFT cohort had a shorter time interval from the date of consult to date of procedure (5.2 vs. 10.8 days). Furthermore, this patient group experienced higher rates of major complications such as stroke (4.4% vs. 1.6%), but not for other complications, such as hematoma formation or cranial nerve injury (8.8% vs. 10.1%). The FFT cohort also had higher rates of hospital transfer (17.7% vs. 4.2%). 13/45 (29%) had complete resolution of the FFT with preoperative heparinization and an additional 9 (20%) demonstrated significant reduction in thrombus size.
Symptomatic carotid artery stenosis with FFT is a very high-risk phenotype of symptomatic carotid stenosis associated with a threefold higher rate of postoperative stroke. Heparinization was associated with a significant reduction in the size of the FFT and facilitated operative intervention without a documented increased in risk of preoperative neurological events.