Symptomatic carotid artery intraluminal thrombus: risk of medical management failure and distal embolization.

Background: 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 to 2023 were identified from our tertiary care institution. Patients with MM failure (recurrent cerebral ischemia and/or symptomatic ICH) were compared with 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, seven (17%) had MM failure with six (14.6%) having new embolic stroke and one (2.3%) with symptomatic ICH. Patients with MM failure had a significantly higher mean thrombus volume than MM non-failure patients (257 mm vs 59.6 mm, 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 showed that an ILT volume of 90 mm 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).

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