Faculty Bibliography

BACKGROUND: The Pipeline embolization device (PED) is a new endoluminal construct designed to exclude aneurysms from the parent cerebrovasculature. We report the very late (>1 year) thrombosis of a PED construct placed for the treatment of a left vertebral aneurysm. CLINICAL PRESENTATION: A patient with an occluded right vertebral artery and a large, fusiform intracranial left vertebral artery aneurysm was treated with PED and coil reconstruction. A durable, complete occlusion of the aneurysm was confirmed with control angiography at 1 year. The patient remained neurologically normal for 23 months until he experienced a transient visual disturbance followed weeks later by a minor brainstem stroke. INTERVENTION: Imaging evaluation showed thrombosis of the PED construct with complete occlusion of the left vertebral artery. After this stroke, he was initially treated with dual antiplatelet therapy and was then converted to warfarin. The patient remained neurologically stable for 5 months until he experienced progressive basilar thrombosis that ultimately resulted in a fatal stroke. CONCLUSION: The PED represents a promising new endovascular technology for the treatment of cerebral aneurysms; however, as an investigational device, long-term follow-up data are sparse at this point. The etiology of the very late thrombosis of the PED construct in this case remains unknown; however, this report underscores the need for a continued, careful systematic evaluation and close long-term follow-up of treated patients

BACKGROUND AND PURPOSE: In-stent restenosis (ISR) occurs in approximately one-third of patients after the percutaneous transluminal angioplasty and stenting of intracranial atherosclerotic lesions with the Wingspan system. We review our experience with target lesion revascularization (TLR) for ISR after Wingspan treatment. METHODS: Clinical and angiographic follow-up results were recorded for all patients from 5 participating institutions in our US Wingspan Registry. ISR was defined as >50% stenosis within or immediately adjacent (within 5 mm) to the implanted stent and >20% absolute luminal loss. RESULTS: To date, 36 patients in the registry have experienced ISR after percutaneous transluminal angioplasty and stenting with Wingspan. Of these patients, 29 (80.6%) have undergone TLR with either angioplasty alone (n=26) or angioplasty with restenting (n=3). Restenting was performed for in-stent dissections that occurred after the initial angioplasty. Of the 29 patients undergoing TLR, 9 required >/=1 interventions for recurrent ISR, for a total of 42 interventions. One major complication, a postprocedural reperfusion hemorrhage, was encountered in the periprocedural period (2.4% per procedure; 3.5% per patient). Angiographic follow-up is available for 22 of 29 patients after TLR. Eleven of 22 (50%) demonstrated recurrent ISR at follow-up angiography. Nine patients have undergone multiple retreatments (2 retreatments, n=6; 3 retreatments, n=2; 4 retreatments, n=1) for recurrent ISR. Nine of 11 recurrent ISR lesions were located within the anterior circulation. The mean age for patients with recurrent anterior circulation ISR was 57.9 years (vs 81 years for posterior circulation ISR). CONCLUSIONS: TLR can be performed for the treatment of intracranial Wingspan ISR with a relatively high degree of safety. However, the TLR results are not durable in approximately 50% of patients, and multiple revascularization procedures may be required in this subgroup

BACKGROUND: The objective of this study is to examine the utility of acetazolamide TCD ultrasound in the evaluation of MCA collateral blood flow reserve in patients with carotid occlusive disease. METHODS: Acetazolamide TCD and cerebral angiography were performed for 28 carotid territories in 14 patients with carotid occlusive disease. The percentage change in mean blood flow velocity and PI in the MCA was measured before and after 1 g of acetazolamide was administered. The carotid territories were divided into groups according their angiographic findings: (1) mild/moderate (<70%) vs severe (> or =70%) extracranial carotid artery stenosis, and (2) active collateral blood flow to the MCA territory vs no collateral blood flow to the MCA. RESULTS: After acetazolamide injection, the percentage increase in mean MCA velocity for mild/moderate vs severe carotid artery stenosis was 43% +/- 10% and 19% +/- 6%, respectively, indicating less collateral blood flow reserve in patients with severe stenosis (P = .04). The percentage decrease in the PI for MCA territories with vs without angiographic evidence of collateral blood flow was 4.6% +/- 4% and 16% +/- 3%, respectively (P = .04), indicating an exhausted vascular reserve in patients with evidence of active collateral blood flow on angiography. CONCLUSIONS: A decrease in the PI after acetazolamide administration represents a safe and noninvasive indicator of limited collateral blood flow reserve to the MCA territory ipsilateral to an extracranial carotid stenosis. Further study into the role acetazolamide TCD has in the preoperative evaluation of these patients, including threshold values, is warranted

OBJECTIVE: To describe a novel double-balloon trapping technique for endovascular embolization of a broad-based saccular aneurysm of the superior cerebellar artery. CLINICAL PRESENTATION: A 62-year-old man with a history of diabetes, coronary artery disease, and smoking presented with a syncopal episode. Catheter angiography revealed a large (11.7 x 9.4 x 11.2 mm) right superior cerebellar artery (SCA) aneurysm with a 7-mm neck, incorporating the origin of the right SCA. INTERVENTION: An endovascular double-balloon trapping technique was used. Using bilateral groin access and bilateral vertebral artery guide catheters, a 4 x 20 mm HyperGlide balloon (ev3 Neurovascular, Irvine, CA) was placed across the neck of the aneurysm, and a 4 x 7 mm HyperForm balloon (ev3 Endovascular Inc., Plymouth, MN) was placed within the aneurysm. The aneurysm was catheterized with an Echelon 14 microcatheter (ev3 Endovascular Inc.). The inflated HyperGlide balloon was used to protect the parent basilar artery and 'trap' the smaller HyperForm balloon within the aneurysm. The HyperForm balloon was inflated within the aneurysm and gently retracted to protect the origin of the SCA at the aneurysm neck. The aneurysm was coiled with the balloons inflated. A 4.5 x 20 mm Neuroform stent (Boston Scientific, Natick, MA) was deployed across the aneurysm neck. Final procedural angiography showed near complete occlusion of the aneurysm and preservation of flow in the SCA. Follow-up angiography at 8 months showed progressive thrombosis with complete occlusion of the aneurysm, preserved patency of the SCA, and anatomic reconstruction of the native artery. The patient remained neurologically normal at the time of the follow-up evaluation. CONCLUSION: Double-balloon trapping is a novel endovascular technique that can be used to treat wide-necked aneurysms and maintain patency of side branches incorporated into the aneurysm neck

OBJECTIVE: Microcatheters retained after Onyx (eV3 Neurovascular, Inc., Irvine, CA) embolization represent a potential source of thromboembolic complications. Catheter retention depends on the degree of Onyx reflux and vessel tortuosity. To overcome this problem, we have adapted a previously described monorail snare technique for stretched coils to remove an adherent microcatheter from the occipital artery during Onyx embolization of a dural arteriovenous fistula. CLINICAL PRESENTATION: We used this technique successfully in a 62-year-old man with a posterior fossa dural arteriovenous fistula. An Echelon-10 microcatheter (eV3 Neurovascular, Inc.) system became adherent in the right occipital artery because of reflux and vessel tortuosity. Significant stretching of the microcatheter was observed during attempted removal. INTERVENTION: A 2-mm Amplatz Goose Neck microsnare (Microvena Corp., White Bear Lake, MN) was placed through a Rapid Transit microcatheter (Cordis Corp., Miami, FL). The hub of the indwelling Echelon microcatheter was cut off and the snare advanced over the outside of the microcatheter. The snare and Rapid Transit microcatheter were then advanced into the guiding catheter (6-French) as a unit over the indwelling Echelon microcatheter. Using the adherent Echelon as a 'monorail' guide, the snare and Rapid Transit microcatheter were advanced distally into the occipital artery and the snare was retracted to engage the microcatheter. The microcatheters and snare were then easily removed because of the second vector of force placed by the snare system on the adherent microcatheter very close to the point of adherence. CONCLUSION: The monorail snare technique represents a simple and safe way to remove an adherent microcatheter from an Onyx cast during the embolization of dural arteriovenous fistulas. Prospective knowledge of this technique will facilitate more aggressive embolization without the reservation that a retained microcatheter could require surgical removal or anticoagulation

OBJECTIVE: A classification system developed to characterize in-stent restenosis (ISR) after coronary percutaneous transluminal angioplasty with stenting was modified and applied to describe the appearance and distribution of ISR occurring after Wingspan (Boston Scientific, Fremont, CA) intracranial percutaneous transluminal angioplasty with stenting. METHODS: A prospective, intention-to-treat, multicenter registry of Wingspan treatment for symptomatic intracranial atherosclerotic disease was maintained. Clinical and angiographic follow-up results were recorded. ISR was defined as greater than 50% stenosis within or immediately adjacent (within 5 mm) to the implanted stent(s) and greater than 20% absolute luminal loss. ISR lesions were classified by angiographic pattern, location, and severity in comparison with the original lesion treated. RESULTS: Imaging follow-up (3-15.5 months) was available for 127 intracranial stenotic lesions treated with Wingspan percutaneous transluminal angioplasty with stenting. Forty-one lesions (32.3%) developed either ISR (n = 36 [28.3%]) or complete stent occlusion (n = 5 [3.9%]) after treatment. When restenotic lesions were characterized using the modified classification system, 25 of 41 (61.0%) were focal lesions involving less than 50% of the length of the stented segment: three were Type IA (focal stenosis involving one end of the stent), 21 were Type IB (focal intrastent stenosis involving a segment completely contained within the stent), and one was Type IC (multiple noncontiguous focal stenoses). Eleven lesions (26.8%) demonstrated diffuse stenosis (>50% of the length of the stented segment): nine were Type II with diffuse intrastent stenosis (completely contained within the stent) and two were Type III with proliferative ISR (extending beyond the stented segment). Five stents were completely occluded at follow-up (Type IV). Of the 36 ISR lesions, 16 were less severe or no worse than the original lesion with respect to severity of stenosis or length of the segment involved; 20 lesions were more severe than the original lesion with respect to the segment length involved (n = 5), actual stenosis severity (n = 6), or both (n = 9). Nine of 10 supraclinoid internal carotid artery ISR lesions and nine of 13 middle cerebral artery ISR lesions were more severe than the original lesion. CONCLUSION: Wingspan ISR typically occurs as a focal lesion. In more than half of ISR cases, the ISR lesion was more extensive than the original lesion treated in terms of lesion length or stenosis severity. Supraclinoid internal carotid artery and middle cerebral artery lesions have a propensity to develop more severe posttreatment stenosis

OBJECTIVE: The Pipeline embolization device (PED; Chestnut Medical, Menlo Park, CA) is a new endovascular construct designed to exclude aneurysms from the parent cerebrovasculature. We report the results of the first two human implantations of this device in North America. CLINICAL PRESENTATION: Two patients presenting with large, symptomatic, circumferential, fusiform intracranial vertebral artery aneurysms were treated with the PED. In both cases, more traditional open microneurosurgical and neuroendovascular treatment strategies had either failed or were associated with unacceptably high risk. INTERVENTION: Three PEDs were placed across the aneurysms in each of the patients to achieve reconstruction of a new parent vessel through the center of a circumferential aneurysm. In the first patient, who had previously been treated with stent-supported coil embolization, the PED construct alone was sufficient to achieve parent vessel reconstruction and exclusion of the recurrent aneurysm. In the second patient, a microcatheter was jailed within the saccular portion of the aneurysm and the parent vessel was reconstructed with three telescoped PEDs. Although the PED construct dramatically reduced flow into the aneurysm, the lesion remained patent. Coiling of the saccular portion of the aneurysm was subsequently performed via the jailed microcatheter. Follow-up angiography performed 72 hours after the procedure demonstrated occlusion of the aneurysm with cylindrical reconstruction of the affected vascular segment. Neither patient has experienced any complication in the periprocedural period (30 d) or during subsequent long-term (>1 year) follow-up. CONCLUSION: The PED represents an important advance in the endovascular therapy of cerebral aneurysms, targeting primary parent vessel reconstruction rather than endosaccular occlusion as a means by which to achieve exclusion of the aneurysm and definitive anatomic reconstruction of the parent artery

OBJECTIVE: To describe a novel technique for single stent reconstruction of wide-necked aneurysms arising from the circle of Willis. METHODS: Neuroform stents (Boston Scientific/Target, Fremont, CA) were placed across the basilar apex (right P1 to left P1) via the posterior communicating artery in two patients, across the left carotid terminus (left A1 to left M1) via the anterior communicating artery in two patients, and across the anterior communicating artery (left A1 to right A1) in one patient for stent-supported coil embolization. RESULTS: Five women underwent successful deployment of the Neuroform stent across the circle of Willis to support subsequent coil embolization of a wide-necked cerebral aneurysm. In two patients with subarachnoid hemorrhage, initial dome coiling was performed for short-term protection, and stents were applied across the circle of Willis to support completion of coil embolization during a second session. None of the patients experienced any periprocedural or delayed neurological complications. CONCLUSION: Stenting across the circle of Willis represents a novel adjuvant technique to support the coiling of selected wide-necked intracranial aneurysms. This technique is particularly useful for wide-necked terminal aneurysms that incorporate both branches of a bifurcation in a configuration unfavorable for Y-stent reconstruction

OBJECTIVE: Wingspan (Boston Scientific, Fremont, CA) is a self-expanding stent designed specifically for the treatment of symptomatic intracranial atheromatous disease. The current series reports the observed incidence of in-stent restenosis (ISR) and thrombosis on angiographic follow-up. METHODS: A prospective, intent-to-treat registry of patients in whom the Wingspan stent system was used to treat symptomatic intracranial atheromatous disease was maintained at five participating institutions. Clinical and angiographic follow-up results were recorded. ISR was defined as stenosis greater than 50% within or immediately adjacent (within 5 mm) to the implanted stents and absolute luminal loss greater than 20%. RESULTS: To date, follow-up imaging (average duration, 5.9 mo; range, 1.5-15.5 mo) is available for 84 lesions treated with the Wingspan stent (78 patients). Follow-up examinations consisted of 65 conventional angiograms, 17 computed tomographic angiograms, and two magnetic resonance angiograms. Of these lesions with follow-up, ISR was documented in 25 and complete thrombosis in four. Two of the 4 patients with stent thrombosis had lengthy lesions requiring more than one stent to bridge the diseased segment. ISR was more frequent (odds ratio, 4.7; 95% confidence intervals, 1.4-15.5) within the anterior circulation (42%) than the posterior circulation (13%). Of the 29 patients with ISR or thrombosis, eight were symptomatic (four with stroke, four with transient ischemic attack) and 15 were retreated. Of the retreatments, four were complicated by clinically silent in-stent dissections, two of which required the placement of a second stent. One was complicated by a postprocedural reperfusion hemorrhage. CONCLUSION: The ISR rate with the Wingspan stent is higher in our series than previously reported, occurring in 29.7% of patients. ISR was more frequent within the anterior circulation than the posterior circulation. Although typically asymptomatic (76% of patients in our series), ISR can cause neurological symptoms and may require target vessel revascularization