Routine aspiration method during filter-protected carotid stenting: histological evaluation of captured debris and predictors for debris amount

Abstract

A routine aspiration method in filter-protected carotid artery stenting (CAS) has been reported recently in which the proximal internal carotid artery (ICA) blood column was aspirated using an aspiration catheter after postdilatation regardless of flow state on digital subtraction angiography. We examined the debris particles captured by this method. The routine aspiration method was used in 71 CAS procedures. In two procedures, captured debris particles were examined histologically. In the remaining 69 procedures, the size and number of debris particles were measured under a stereoscopic microscope, and then relationships between the amount of debris particles and clinical variables were evaluated using multivariate regression analysis. Histologically, the captured debris contained platelet-precipitating, thrombotic, lipid-rich fibrous and calcified material. The number of debris particles ≥1 mm was 19.6 ± 12.1 (mean ± SD) in 60 procedures with normal flow and 25.9 ± 17.2 (mean ± SD) in 9 procedures with slow/stop flow. Multivariate regression analysis demonstrated that extension of a proximal ICA angulation was an independent predictor of the amount of debris particles with a maximum diameter of either ≥1 mm or <1 mm but ≥0.5 mm (p < 0.05). The captured debris appeared to originate from atheromatous plaques. If the routine aspiration method had not been used in the present series, the debris might have migrated into intracerebral arteries. Restriction of the extension of a proximal ICA angulation might reduce the amount of debris associated with CAS, especially when the proximal ICA angulation is pronounced.