Intravascular ultrasound identification of intraluminal embolic plaque material during carotid angioplasty with stenting.

INTRODUCTION: Carotid angioplasty with stenting (CAS) has evolved as a viable method for treating patients at high risk for carotid endarterectomy. Strokes complicating CAS are most commonly caused by the liberation and distal embolization of embolic material from plaque during the procedure.
METHODS: CAS with distal embolic protection (DEP) was performed using the assistance of intravascular ultrasound (IVUS) in a 68-year-old man with asymptomatic carotid artery stenosis. Evaluation of the plaque pretreatment was performed using virtual histology software. IVUS evaluation was also performed after prestent angioplasty, stenting, and poststent angioplasty.
RESULTS: Initial degree of angiographic stenosis was 78.9%. Final degree of stenosis was 15.7%. By IVUS, stenosis by minimum lumen diameter and minimum lumen area were 75.6% and 93.4% pretreatment, respectively, and 42.2% and 47.1% posttreatment, respectively. An intraluminal lesion was noted in the distal aspect of the stent after poststent angioplasty but before DEP device removal. Ultrasonographic characteristics of the intraluminal defect were consistent with ruptured plaque material. Angiographic runs failed to demonstrate the lesion. A repeat IVUS run performed approximately 10 min later failed to depict the lesion, suggesting that distal embolization had occurred. Embolic material was noticed in the DEP device after removal. The patient did not experience any ischemic neurological symptoms.
CONCLUSIONS: IVUS can identify intraluminal plaque material, which may be a precursor for embolism and delayed ischemic events after CAS. IVUS may allow for treatment before distal embolization of plaque material. Virtual histology IVUS software may help to identify carotid lesions at higher risk for significant embolization during CAS.