Proximal Protection Devices for Carotid Artery Stent Placement: A Benchtop Assessment of Flow Reversal Performance

BACKGROUND AND PURPOSE: Proximal protection devices, such as TransCarotid Artery Revascularization (TCAR), aim to yield better outcomes in carotid artery stent placement (CAS) than distal protection devices by preventing plaque embolization to the brain. However, transfemoral catheters may not fully reverse flow from the external carotid artery (ECA) to the ICA. We assess a new balloon-sheath device, Femoral Flow Reversal Access for Carotid Artery Stent placement (FFRACAS), for this purpose.

MATERIALS AND METHODS: The FFRACAS prototype (inner diameter [ID] = 0.117 inches; L = 80 cm) was compared with TCAR (ID = 0.104 inches, L = 30 cm) and Mo.Ma (ID = 0.083 inches, L = 90 cm) in a pulsatile flow model with blood simulant at 800 mL/min. Mo.Ma was used according to labeled instructions, with both CCA and ECA balloon inflation, without CCA-femoral vein shunt placement, and in an off-label fashion with single balloon occlusion in the CCA and shunt. Flow rates of the ICA, ECA, and shunt, when applicable, were monitored during CAS stages: CCA flow arrest, shunt activation, and stent delivery. Experiments were conducted under 2 ECA inflow conditions (−10 and −20 mL/min). Statistical comparison of ICA flow rates was conducted by using ANOVA and Tukey post hoc tests.

RESULTS: The on-label use of Mo.Ma maintained retrograde ICA flow (−0.3 mL/min) throughout CAS. On shunt activation, TCAR and FFRACAS reversed ICA flow similarly under low ECA inflow (ICA = −5.10 mL/min versus −4.83 mL/min; P = .349), but neither achieved ICA flow reversal under high ECA inflow or during stent delivery. Mo.Ma off-label use failed to reverse ICA flow.

CONCLUSIONS: FFRACAS presents a potential alternative to TCAR, achieving similar degrees of flow reversal from a transfemoral approach to that achieved with the transcarotid approach. The Mo.Ma system reliably prevents anterograde flow in ICA during CAS.