Neuroprotection for Ostial Common Carotid Stenoses
The "double-wire" technique is an effective method of treating these complex lesions.
The technical aspects of stenting for bifurcation disease involving the origin of the internal carotid artery have been widely discussed and published. The procedural details of stenting atherosclerotic disease of the origin of the common carotid artery, however, are less well known. With the resurgence of diagnostic carotid angiography and the increasing use of CT angiography and MR angiography, physicians are finding that carotid disease is often not limited to the internal carotid artery. It is not uncommon to find significant ostial disease of the common carotid artery and innominate artery, and occasionally significant disease will occur in tandem. In such instances, the traditional approach to the disease has involved carotid endarterectomy combined with intra- or extrathoracic carotid bypass surgery.
A NEW APPROACH
Modifications of this traditional approach to tandem carotid disease involving both the common and internal arteries have evolved over time. Arko1 and Allie2 have separately reported a high degree of success in combining carotid endarterectomy with retrograde stenting of the common carotid or innominate artery via a sheath delivered through the operative field. In cases in which the disease is limited to the common carotid artery with no internal carotid disease, others have demonstrated success with stenting,3 but have routinely done so in the absence of neuroprotection. Existing carotid stent platforms and distal protection devices now allow for routine stenting in such conditions with a pure endovascular approach.
To properly approach a carotid case that includes ostial disease of the left common carotid artery, one must obtain a good-quality arch aortogram in the left anterior oblique projection (Figure 1A). Conversely, disease involving the innominate artery of the right common carotid artery will typically require a similar angiogram in the right anterior oblique projection (Figure 1B). These views are ultimately critical to the intervention to avoid extending the stent too far into the aorta or unnecessarily across the right subclavian origin.
Once the ostial disease has been visualized, selective angiograms of the entire carotid circulation can be obtained with a relatively benign catheter such as a Sos Omni (AngioDynamics, Inc., Queensbury, NY), Vitek (Cook Incorporated, Indianapolis, IN), or a simple catheter such as a JR4, HB1, or vertebral curve (Figure 2A). With the catheter resting at the origin of the disease, one can then pass an exchange-length, .018-inch wire gently through the ostial lesion and into the distal common carotid or external carotid artery with relative ease. At this point, the diagnostic catheter is exchanged for an 8-F guide catheter or a 6-F sheath over the .018-inch wire (depending on the complexity and angulation of the target vessel) (Figure 2B).
With the .018-inch wire in place and the guide or sheath resting just outside the origin of the brachiocephalic vessel, a .014-inch distal protection filter can be easily advanced through the lesion and to its distal target (Figure 2C). In cases in which the internal carotid artery is not severely diseased and the distal common carotid artery is of modest diameter, one can consider deploying a large-diameter filter in the distal common carotid artery. In most cases, however, there is either a significant lesion of the internal origin or the distal common diameter is too generous, thus requiring placement of the filter in its usual position in the C1 segment of the internal carotid artery proper. Having accomplished filter placement, the intervention can proceed with true neuroprotection.
The placement of an .018-inch wire combined with the .014-inch platform of a filter comprises the "double-wire" technique that, in combination with the guide or sheath, forms a very stable delivery system for stenting of ostial common carotid disease (Figure 2D-F). The combined diameters of the two wires (.032-inch) approximate the operating parameters of virtually all .035-inch stent platforms, and such stents can be fed simultaneously over both wires with good support. It is our preference and recommendation that balloon-expandable platforms be utilized for stenting of ostial disease of the common carotid artery in this manner. The location of such lesions is not subject to external compression due to their intrathoracic location. Balloon-expandable stents are also more visible, enabling more accurate positioning. In addition, such stents have more radial strength, which is ideal for stenoses in this position.
Once the ostial common carotid lesion has been successfully treated, the guide or sheath (with introducer repositioning) can then be advanced more distally into the common carotid artery if necessary for better support in cases that also require stenting of the internal carotid artery. The internal carotid stenosis is treated using the standard technique. The .018-inch wire can be removed or withdrawn into the mid-common carotid artery at this point so that the wire is not trapped behind the self-expanding stent that is subsequently delivered to the internal carotid bifurcation.
The "double-wire" technique has proven useful for a number of different lesions and combinations of stenoses. Isolated stenoses of the innominate artery, right and left common carotid artery, and select subclavian artery (where complex lesions may threaten the posterior circulation) may all benefit from this approach. The same is true when treating combined disease of these proximal lesions that coexist with hemodynamically significant stenosis of the internal carotid artery.
Most of the reasons that interventionists offer for not using distal protection in procedures involving proximal common carotid locations center around physician convenience and a hopeful belief that such lesions have a lesser embolic potential. However, as our experience in the pre-embolic protection era has taught us, such an approach will eventually lead to a bad and avoidable outcome. The "double-wire" technique described is relatively simple and thus far effective in treating these more complex carotid lesions.
James Joye, DO, is Director of Interventional Services, El Camino Hospital, and Director, Peripheral Vascular Interventions, The Cardiovascular Institute, Mountain View, California. He has disclosed that he holds no financial interest in any product or manufacturer mentioned herein. Dr. Joye may be reached at (650) 969-8600; firstname.lastname@example.org..