Double Wire Technique for Intracranial Stent Navigation

Editor: Evolutionary advancement of stent technology allows us to expand the therapeutic options in the field of neuroendovascular treatment. Stent placement for extracranial carotid stenosis can be accomplished at a high rate with acceptably low rates of morbidity and mortality. These excellent results have encouraged neurointerventionalists to place stents for treatment of vascular stenoses and aneurysms involving intracranial vessels (1–3). To advance a stent delivery system in the intracranial vessels, the tip of the guide wire should be placed as distally as possible to allow the best support. The guiding catheter should be positioned as close to the base of the skull as possible to maintain good catheter support during stent navigation. In almost all patients in one reported series, intracranial stent deployment was performed successfully with use of these standard techniques; however, in some patients, this procedure failed to access the objective lesion because of vessel tortuosity. We describe a new technique that can successfully navigate a stent delivery system in these difficult cases. Vessel tortuosity from the base of the skull to intracranial lesions has limited the use of stent therapy. Acute angles of tortuous vessel limit the ability to cross the distal edge of the stent or balloon catheter and stent delivery systems often stop at this site (Figure, parts a, b). At this point, stent navigation with the standard technique should be stopped and the stent delivery system should be withdrawn, leaving the guide wire for the stent delivery system across the intracranial lesion. Another guide wire is advanced across the acute angled curve. Two guide wires are now positioned in the objective lumen. At this time, it is important to deliver the second guide wire on the path of the distal edge of the stent or balloon catheter. Then the stent delivery system is advanced again. When a bare guide wire exists between the arterial wall and the stent, the stent delivery system can pass the acute angled curve with significantly less resistance (Figure, parts c, d). The second guide wire is withdrawn when the stent is positioned at the level of interest, just before expansion. This technique can be adapted to vessels with reference diameters of at least 3 mm in because it is necessary to insert a stent delivery system and another guide wire though the same vessel. In the field of cardiovascular intervention, it is reported that placing stents in vessels smaller than 3 mm causes a higher incidence of acute complications (dissection and acute closure) and a higher incidence of restenosis during follow-up. Therefore, this double-wire technique may be used for the treatment of many intracranial lesions with intracranial stent placement. Endovascular stent placement for cerebrovascular disease has been proven to be a successful treatment option. Stents used for intracranial lesions of cerebral aneurysms or vascular stenoses have primarily been treated with coronary balloon-expandable stents (1–3). Second-generation coronary stents demonstrate excellent flexibility and “trackability” and allow for treatment of intracranial vascular lesions. This procedure promises a new therapeutic era. However, the safe and smooth navigation of a coronary stent system into intracranial lesions is difficult because there are significant differences in physical properties and architecture between the coronary and cerebral vasculatures. Stent system delivery across a tortuous carotid siphon or upper segment of vertebral artery is particularly difficult. Gomez et al (4) reported a 33% success rate of stent navigation into the intracranial carotid artery above the supraclinoid portion with use of standard technique. It is doubtful that uneventful passage of current coronary stent systems has been possible in all patients with cerebral arteriosclerosis. The stent delivery system should be not forced, but gently navigated into intracranial lesion. The friction seen between the distal edge of the stent and the arterial wall prevents smooth navigation of stent delivery systems, and forceful pushing may lead to tremendous complications including stent edge dissection or deformation or migration of the stent. Stent edge dissection can cause pseudoaneurysm, which may cause supraclinoid hemorrhage or cerebral embolism. The deformation and migration of the stent may lead to abrupt closure of the intracranial carotid artery and massive cerebral infarction. Therefore, a technique with safe and smooth intracranial stent navigation is required to perform this endovascular procedure without complications. In the doublewire technique, a second guide wire is placed parallel and adjacent to the stent delivery system. The adjacent wire appears to facilitate the advancement of the stent and stent delivery system in acutely angled vessels. The role of the adjacent wire is to provide a “railway” for the stent and stent delivery system. A possible mechanism for beneficial effects may be that the wire diminishes friction between the arterial wall and the stent delivery system. The adjacent wire should be stuck on a arterial wall and placed between the arterial wall and the stent. Another consideration is that the wire makes an obtuse angle to advance the stent delivery system. Therefore, we recommend selecting a 0.016or 0.014-inch guide wire with stiffness, steerability, and slippery surface as the adjacent wire. The disadvantage of this technique is that it requires additional complex manipulation. It should be considered that a more complex procedure increases the risk of thromboembolic complications compared to the standard technique. Therefore, we believe that strict anticoagulation therapy is needed to prevent thromboembolism durDOI: 10.1097/01.RVI.0000071092.76348.2E Letter to the Editor