Commentary: Transcervical Carotid Artery Stenting (CAS) With Flow Reversal

In this issue of the JEVT, Plessers et al compared the results of carotid endarterectomy (CEA) with both transfemoral carotid artery stenting (CAS) with distal filters and transcervical CAS with dynamic flow reversal. CAS with distal filters showed higher embolization rates compared with either CEA or CAS with flow reversal both in the preprotection and the protection phases. On the other hand, CAS with flow reversal had no difference in perioperative embolization rates during any phases compared with CEA. The authors concluded that transcervical CAS with dynamic flow reversal is a promising technique and may be the preferred option to reduce CAS-associated stroke rates. Despite being less invasive, CAS is often associated with higher stroke rates compared with CEA. Manipulation of guidewires and catheters in a stenotic carotid artery or aortic arch over a vulnerable, “unstable” plaque may often scrape off thromboembolic or atheroembolic material, thus resulting in stroke or transient ischemic attacks. Consequently, cerebral protection techniques/devices aiming to reduce the embolic stroke rates during/after CAS would improve the appeal of the procedure. Several concepts for cerebral protection devices have been developed in an attempt to reduce the chances of clinically significant embolic events in the brain. These include (1) balloon occlusion of the internal carotid artery (ICA) followed by aspiration of debris [ie, PercuSurge (Medtronic, Minneapolis, MN, USA)], (2) Kachel’s technique using balloon occlusion of the common carotid artery (CCA), (3) filter-type devices placed in the ICA [such as Angioguard (Cordis, Bridgewater, NJ, USA)], (4) cessation of ICA blood flow achieved by balloon occlusion of the CCA and external carotid artery (ECA) followed by catheter aspiration of debris [Mo.Ma (Medtronic)], and (5) combinations of these techniques. The first observation that flow reversal could be used as a cerebral protection device occurred in 1988. While Juan Parodi was performing a CEA using a shunt, he used transcranial Doppler to monitor middle cerebral artery (MCA) embolization. After clamping the CCA, ICA, and ECA, a longitudinal arteriotomy was performed, and the shunt was inserted in the distal ICA. With one end of the shunt in the ICA and the other end open to flush blood from the ICA, flow reversal was detected in the MCA. By occluding the end of the shunt, flow in the MCA reverted to antegrade due to the presence of communicating arteries. The first transcervical CAS procedures were performed accessing the proximal CCA through a small incision at the base of the neck. After occluding the CCA with a clamp, an 8-F introducer was placed in the CCA over a guidewire inserted in the ECA. Once the 8-F sheath was in place, either a 4.5-mm coronary balloon or a PercuSurge occlusion balloon was inflated. The side port of the 8-F sheath was connected to a 6-F sheath introduced in the adjacent internal jugular vein, with a transfusion blood filter in between. Once flow reversal was produced, the ICA lesion was predilated and stented. After aspiration, the 8-F sheath was removed. No high-intensity transitory signals (HITS) were detected in 633830 JETXXX10.1177/1526602816633830Journal of Endovascular TherapyParaskevas et al research-article2016