Proximal protection devices for carotid artery stenting – A benchtop assessment of flow reversal performance

BACKGROUND AND PURPOSE: Proximal protection devices, such as TransCarotid Artery Revascularization (TCAR, SilkRoad Medical, Sunnyvale), aim to yield better outcomes in carotid artery stenting (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 internal carotid artery (ICA). We assess a new balloon-sheath device, Femoral Flow Reversal Access for Carotid Artery Stenting (FFRACAS), for this purpose.

MATERIALS AND METHODS: The FFRACAS prototype (ID = 0.117”; L=80cm) was compared to TCAR (ID=0.104”, L=30cm) and MoMa (Medtronic, Minneapolis; ID=0.083”, L=90cm) in a pulsatile flow model with blood simulant at 800mL/min. MoMa 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 two ECA inflow conditions (-10 and -20 mL/min). Statistical comparison of ICA flow rates was conducted using ANOVA and Tukey’s post-hoc tests.

RESULTS: MoMa’s on-label use maintained retrograde ICA flow (-0.3 mL/min) throughout CAS. Upon shunt activation, TCAR and FFRACAS reversed ICA flow similarly under low ECA inflow (ICA=-5.10 mL/min vs. -4.83 mL/min; p=0.349), but neither achieved ICA flow reversal under high ECA inflow or during stent delivery. MoMa 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 MoMa system reliably prevents anterograde flow in ICA during CAS.

ABBREVIATIONS: CAS = Carotid Artery Stenting; TCAR = Transcarotid Arterial Revascularization; CCA = Common Carotid Artery; ICA = Internal Carotid Artery; ECA = External Carotid Artery; VA = Vertebral Artery; FFRACAS = Femoral Flow Reversal Access for Carotid Artery Stenting; ID = Inner Diameter; OD = Outer Diameter.