Article Text
Abstract
The use of the Wingspan stent in severe intracranial stenosis is associated with a relatively high in-stent re-stenosis rate. Reported management strategies for re-stenosis have included angioplasty alone or angioplasty with placement of a second Wingspan stent. A case is presented in which thrombosis within a Wingspan stent was treated with a balloon expandable cobalt-chromium stent within the Wingspan stent. Subsequent follow-up imaging has shown persistent patency of the treated vessel, with no subsequent in-stent stenosis.
- Artery
- Stenosis
- Complication
- Stent
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Introduction
Intracranial stenosis represents a significant problem, estimated to account for approximately 8–10% of new stroke cases in the USA.1 The natural course of the disease appears to be relatively aggressive, with some authors reporting as high as a 15% annual stroke risk in patients with symptomatic intracranial stenosis.2 Recent prospective research has suggested that medical management in the form of antiplatelet agents is by itself suboptimal, with as high as a 29% recurrent stroke risk at 2 years for certain patient demographics.3 Over the past 2 decades, endovascular angioplasty and stenting has been increasingly used for the treatment of intracranial atherosclerotic disease (ICAD).4 Debate currently continues on the optimal endovascular therapy, with possible options including percutaneous transluminal angioplasty and/or stenting, using either balloon mounted or self-expanding stents.
Currently, only the Wingspan self-expandable stent system (Boston Scientific, Fremont, California, USA) is FDA approved for use in ICAD5 although numerous authors report the off-label use of balloon mounted coronary stents for the same indication. The use of endovascular stents, whether self-expanding or balloon mounted, carries a significant risk of delayed in-stent re-stenosis6–8 although many remain asymptomatic. Management strategies for re-stenosis have been described and include medical management (particularly for asymptomatic lesions), angioplasty alone or angioplasty with placement of a second Wingspan stent.3 To date, no definitive answer has been reached for the optimum treatment of delayed re-stenosis follow stent placement for ICAD.
We present a case in which the Wingspan stent was used to treat intracranial stenosis. In this case, in-stent re-stenosis and thrombosis occurred. The thrombosis was treated with thrombolysis, and ultimately a balloon expandable cobalt–chromium stent (Guidant, Indianapolis, Indiana, USA) was deployed within the initial Wingspan stent to treat the residual stenosis. Following the placement of the second stent, short term and intermediate follow-up studies have shown that the treated vessel has remained widely patent.
Case report
A middle-aged person presented to our Interventional Neuroradiology Clinic for evaluation of possible endovascular treatment of vertebrobasilar insufficiency. The patient had a history of vertebrobasilar insufficiency and associated episodic transient ischemic attacks (TIAs), consisting of right- and left-sided numbness and paresthesias, slurred speech and vertical diplopia, all of which would resolve over several minutes. The patient was followed by a neurologist and was managed medically with Aggrenox; however, their symptoms persisted despite management. Prior to their presentation to our clinic, the patient suffered a TIA lasting approximately 1 h. At this time, their regimen was switched to Plavix alone, and he was scheduled to follow-up in our clinic. MRI done at the time of presentation to our clinic revealed multiple small, chronic infarctions involving the posterior circulation territory, with no evidence of acute infarction. MR angiography demonstrated a high grade stenosis of the vertebrobasilar junction, involving the distal left vertebral and proximal basilar arteries. Due to their persistent symptoms of vertebrobasilar insufficiency despite medical management, the patient elected to undergo angioplasty and stenting of his vertebrobasilar stenosis. During catheter angiography, the lesion was found to be a 12 mm segment of irregular, high grade (90%) stenosis of the vertebrobasilar junction, involving the distal left vertebral and proximal basilar arteries (figure 1A). The lesion was successfully balloon angioplastied, and a 3×20 mm Wingspan stent was placed, resulting in 40–50% residual stenosis (figure 1B). The patient tolerated the procedure well and was discharged in a stable neurologic condition. Post-procedurally, he was maintained on clopidogrel (75 mg daily) and aspirin (325 mg daily) for 90 days and then switched to aspirin alone.
Four months later, the patient presented to our emergency department with acute onset of left arm and leg weakness and numbness, dysarthria, tinnitus and swallowing difficulty. Their rating on the National Institutes of Health Stroke Scale was 13 (level of consciousness 1, gaze preference 1, facial palsy 2, left arm weakness 2, left leg weakness 3, left hemisensory loss 1, ataxia 2 and dysarthria 1). Due to the emergent nature of the treatment, verbal and written informed consent was obtained from the patient and their family for the procedure, including the potential off-label use of an FDA approved device (balloon mounted stent). The patient was taken emergently to the angiography suite, and a catheter angiogram revealed in-stent thrombosis with occlusion of the distal left vertebral and proximal basilar arteries (figure 2A). Intra-arterial thrombolysis was performed with 25 mg of abciximab. Balloon angioplasty was then attempted three times but significant residual stenosis remained (figure 2B). Finally, a 2.5×18 mm Guidant cobalt–chromium stent was placed through the residual stenosis and deployed, with a good angiographic result. This stent was shorter than the original Wingspan stent and was positioned entirely within the Wingspan stent. Residual thrombus remained in the basilar tip, which was thrombolysed with 2 mg of tissue plasminogen activator, resulting in resolution of the thrombus. The final post-procedural angiogram showed the stent to be patent, without residual stenosis (figure 2C). The patient was placed on clopidogrel (75 mg daily) and aspirin (325 mg daily), and was discharged to a skilled nursing facility with a National Institutes of Health Stroke Scale of 2 (mild left facial droop 1, mild dysarthria 1). Of note, the weakness in the left upper/lower extremities had completely resolved by the time of discharge.
The patient recovered from all neurologic deficits, and routine follow-up angiography at 6 and 16 months has demonstrated persistent wide patency of the vertebrobasilar stent with no in-stent stenosis or flow limitation (figure 3).
Discussion
Angioplasty and stenting have been shown to be viable treatment strategies for symptomatic ICAD4 and the Wingspan stent system is currently the only stent approved by the FDA for this indication. The Wingspan stent has demonstrated reasonable safety and efficacy in the treatment of ICAD but recent studies have demonstrated in-stent re-stenosis and thrombosis rates as high as 30%6 7 although many of these incidents of re-stenosis remain asymptomatic. The treatments described for re-stenosis include angioplasty alone and angioplasty with restenting, as well as medical therapy for asymptomatic re-stenosis. Restenting has been previously described when angioplasty causes in-stent dissection and the literature only describes Wingspan stents being used for re-stenting in this situation.7
In this patient, any of a number of factors may have contributed to the delayed re-stenosis of the Wingspan stent. Firstly, immediate post-procedural imaging following stent deployment shows a residual stenosis of 40–50%. Although a suboptimal angiographic result, post-stent angioplasty was not performed in accordance with the manufacturer's recommendations at that time. Indeed, some degree of residual stenosis following Wingspan placement for ICAD is common, with the average residual stenosis in the range of 20–40%.9
Secondly, although medical compliance was never confirmed, the occurrence of the delayed thrombosis approximated the termination of the patient's dual antiplatelet regimen. The patient was initiated on dual antiplatelet agents (aspirin 325 mg daily and clopidogrel 75 mg daily) prior to the stenting procedure. Following the procedure, the patient was maintained on both drugs for 90 days, after which clopidogrel was discontinued. Temporally, the thrombosis occurred 3 weeks following this change from dual antiplatelet agents to aspirin alone. In addition, at the time of the procedure, routine testing of the efficacy of aspirin and clopidogrel was not being performed at our institution whereas now all patients are routinely screened for this. Indeed, optimizing the antiplatelet regimen should help to decrease the risk of delayed re-stenosis and/or thrombosis.
Our case highlights the potential application of balloon expandable stents as rescue devices for in-stent re-stenosis and/or thrombosis following Wingspan placement. In this case, repeated balloon angioplasty resulted in suboptimal treatment of the in-stent thrombosis. The balloon mounted coronary stent re-established patency of the vessel with minimal resultant residual stenosis. Although an off-label use for coronary stents, treatment of ICAD with them has been demonstrated to be effective.10–12 It was thought that the balloon expandable stents, which are stiffer and more difficult to maneuver through tortuous anatomy than self-expandable stent systems, were associated with increased peri-procedural morbidity and mortality.13 Recent reviews show that this may not be true.4 In addition, balloon mounted stents result in less residual stenosis on average than do self-expanding stents when treating ICAD, which may help to account for the persistent patency of the rescue stent in this case.
Our understanding of the roles of angioplasty and stenting in the treatment of ICAD remains incomplete. The results of this case report support the need to explore and expand our knowledge regarding the etiology and significance of re-stenosis and delayed thrombosis, as well the most effective methods of dealing with these complications. Continued research on the subject is clearly warranted.
References
Footnotes
Competing interests None.
Patient consent Obtained.
Provenance and peer review Not commissioned; not externally peer reviewed.