Efficacy of a proximal occlusion catheter with reversal of flow in the prevention of embolic events during carotid artery stenting: An experimental analysis

Objective: The role of percutaneous angioplasty and stenting of carotid bif urcation lesions has been limited by its potential for producing embolic de bris. We evaluated the efficacy of a proximal occlusion catheter (POC) in t he prevention Of embolic events during carotid artery stenting. In addition , pressure measurements relevant to the clinical application Of this device were obtained from 10 patients undergoing carotid endarterectomy. Methods: The POC is a guiding catheter with an occlusion balloon attached o n the outside of the catheter at its distal end. Occlusion of the common ca rotid artery (CCA) was achieved by inflating the balloon while access to ca rotid bifurcation lesions was obtained through the inner lumen. The POC was inserted in the CCA of 10 dogs via the femoral artery. The side port of th e POC was connected to a sheath placed in the femoral vein, thereby creatin g an external arteriovenous shunt. Ten artificial radiopaque particles simu lating embolic particles and contrast agent were introduced in the CCA and monitored fluoroscopically. As a control, the same procedure was performed with a standard guiding catheter without an occlusion balloon. In 10 patien ts undergoing carotid endarterectomy, the internal carotid artery (ICA) and external carotid artery stump pressures and the pressure in the internal j ugular vein were measured. Results. Without the external arteriovenous shunt, in all animals there was prograde flow in the distal CCA despite CCA occlusion. This flow was deriv ed from the thyroid artery. However, once the arteriovenous shunt was activ ated, reversal of now in the distal CCA was achieved in each animal, and al l the artificial particles were recovered from the side port of the POC. In the control group, each particle embolized to the brain (100%, P < .01). I n the patients, the mean stump pressures in the ICA and external carotid ar tery and the jugular vein pressure mere 51.8 +/- 14.2, 62.2 +/- 15.1, and 6 .5 +/- 3.5 mm Hg, respectively. In each case, the jugular vein pressure was the lowest among the three. Conclusions: Obtaining proximal CCA control by inflating the POC does not s ufficiently prevent embolization. However, reversal of flow in the ICA can always be created with the external shunt, which effectively prevents embol ization. Thus, POC may markedly lower procedural stroke rates during caroti d artery stenting. The ability of POC to prevent embolization before crossi ng the lesion with a guidewire may be an important advantage over other dis tal protection devices.