RS07 - Post-operative Complications After Carotid Endarterectomy for Free Floating Thrombus

Objectives: 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. Our study sought to bridge this gap through a retrospective chart review of patients who underwent a CEA for symptomatic FFT.

Methods: 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 from 2010-2020. Patients were identified after radiographic review of CT angiography at 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.

Results: During the study period 802 CEA were performed, with a total of 45 patients identified with FFT. Patients in the FFT cohort had shorter time interval from date of consult to date of procedure (5.2 vs. 10.8 days). Furthermore, they experienced higher rates of major complications such as stroke (4.4% vs. 1.6%), but not for others, such as hematoma formation or cranial nerve damage (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 pre-operative heparinization and an additional 9 (20%) demonstrated significant reduction in thrombus size.

Conclusions: Symptomatic carotid artery stenosis with FFT is a very high risk phenotype of symptomatic carotid stenosis, associated with a threefold higher rate of post-operative stroke. Heparinization was associated with significant reduction in size of the FFT and facilitated operative intervention without a documented increase in risk of pre-operative neurological events.