Symptomatic Carotid Artery Intraluminal Thrombus: Risk of Medical Management Failure and Distal Embolization

Introduction: Carotid artery intraluminal thrombus (ILT), or free-floating thrombus, is an uncommon cerebrovascular entity with considerable equipoise regarding its clinical management. Likewise, in patients treated with medical management (MM), distal embolization and/or intracranial hemorrhage (ICH) may still occur.

Methods: All patients with symptomatic ILT from 2016-2023 were identified from our tertiary care institution. Patients with MM failure (recurrent cerebral ischemia and/or symptomatic ICH) were compared to patients with MM non-failure. Differences in ILT volume and length were calculated. Receiver operator characteristic (ROC) curve analysis was used to identify the cut-off volume and length for risk of MM failure.

Results: In total, 45 patients with ILT were identified with 41 treated with frontline MM. Of these 41 patients treated with MM, 7 (17%) had MM failure with 6 (14.6%) having new embolic stroke and 1 (2.3%) with sICH. Patients with MM failure had a significantly higher mean thrombus volume compared to MM non-failure patients (257 mm3 vs. 59.6 mm3, P = 0.0006). Likewise, patients with MM failure had significantly longer thrombus on average (21 mm vs. 6.6 mm, P=0.0009). ROC curve analysis demonstrated that an ILT volume of 90 mm3 resulted in a sensitivity of 71.4% and specificity of 85.3% for MM failure (AUC: 0.775; CI: 0.55 to 1.0, P=0.023). For thrombus length, a cut-off value of 6 mm for MM failure was found to have a sensitivity of 71.4% and specificity of 64.7% (AUC: 0.697; CI: 0.43 to 0.97, P = 0.10).

Conclusion : Carotid ILT that fail MM are significantly larger and longer. These findings suggest that a thrombus volume of 90 mm3 may serve as a guide for intervention with good sensitivity and specificity for risk of MM failure.