SS06 - Patients with Carotid Occlusion Require Close Surveillance and Have a High Rate of Subsequent Carotid Intervention

Objectives: There is a paucity of literature on the natural history of extracranial carotid artery occlusion (CAO). This study reviews the natural history of this patient cohort.

Methods: This single-institution retrospective analysis studied patients with CAO diagnosed by duplex ultrasound between 2010 and 2021. Patients were identified by searching our office-based accredited vascular laboratory database. Imaging and clinical data was obtained via our institutional Electronic Medical Record.

Results: 5523 patients underwent carotid artery duplex exam during the study period. The CAO cohort consisted of 140 patients, as characterized in Table 1; incidence of CAO was 2.5%. 61.3% (n=86) of patients were asymptomatic at diagnosis. 27.9.% (n=39) were diagnosed after a stroke or TIA, with 16.4% ipsilaterally affected, 7.9% contralaterally affected, and 3.6% with unclear laterality. For 23 patients with prior duplex imaging demonstrating ipsilateral patency, 26.1% had < 50% ipsilateral stenosis, 39.1% had 50-69% stenosis, and 26.1% had >70% stenosis at a mean of 32.8±26.4 months prior to CAO diagnosis. At CAO diagnosis, 55.2% of patients had < 50% contralateral stenosis, 24.8% had 50-69% stenosis, and 9.9% had >70% stenosis.

Ninety-five patients (67.9%) had duplex imaging follow-up (mean 42.7±31.3 months). Six patients (6.3%) developed recanalization with mean occurrence 42.9±32.6 months post-diagnosis. Four patients (2.9%) developed subsequent stroke ipsilateral to the CAO with mean occurrence 27.8 ±39.0 months post-diagnosis. Thirteen patients (9.3%) developed other related symptoms, including global hypoperfusion (5.0%), cognitive changes (2.9%), and TIA (1.4%).

Ten patients (7.1%) underwent eventual ipsilateral intervention, including CEA (n=6), TF-CAS (n=2), TCAR (n=1), and carotid bypass (n=1), with mean occurrence 17.7±23.7 months post-diagnosis. Prior to intervention, 7 occlusions on duplex imaging were recharacterized as severe stenosis per periprocedural CT or MR imaging. Two CAOs were intervened upon subsequent to recanalization. One patient with confirmed CAO underwent bypass for symptoms of global cerebral hypoperfusion. Intervention characteristics are shown in Table 2. The aggregate rate of developing recanalization, related stroke or symptoms, or undergoing ipsilateral intervention was 19.3%. 16 patients (11.4%) underwent contralateral intervention, including CEA (8.6%), TCAR (2.1%), and TF-CAS (.7%), with mean occurrence 11.5±18.2 months post-diagnosis.

Conclusions: In this large, institutional cohort of patients with CAO diagnosed by duplex ultrasound, a clinically meaningful subset of patients experienced recanalization, stroke, or related symptoms. Most patients with CAO per duplex ultrasound who underwent intervention were subsequently recharacterized as having severe stenosis. These data suggest that patients with CAO may benefit from aggressive medical management, close follow up, and confirmatory imaging.