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BACKGROUND: Atherosclerotic occlusive disease of the vertebral artery (VA) affects a significant proportion of patients with cerebrovascular disease and can cause significant morbidity and mortality despite maximal medical therapy. Careful selection of both symptomatic and asymptomatic patients for intervention based on neurological symptoms, as well as anatomical and hemodynamic considerations, is essential. METHODS: To achieve proper results with angioplasty and stenting, standard endovascular techniques are modified for the unique anatomical considerations of the VA. Several technical nuances are described here to aid in the endoluminal revascularization of the VA. RESULTS: Technical success (<50% residual diameter stenosis) rates ranging from 94 to 98% and low rates of periprocedural complications have been achieved with VA angioplasty and stenting in select series with angiographic follow-up. The long-term success in those series is limited by the high (10-43%) rate of recurrent stenosis. Proper placement of the stent can reduce the risk of periprocedural complications and restenosis. In-stent stenosis appears most commonly during the first 6-12 months after stent placement, but does not appear to correlate with return of neurological symptoms. We believe the high rate of recurrent stenosis makes follow-up angiography essential, especially in the first 12 months after the procedure. CONCLUSION: Endovascular VA angioplasty with stent placement provides an innovative approach to treat a difficult clinical entity. Evolving therapies, including drug-eluting stents or bioresorbable stents, may prove to provide better long-term results. [ABSTRACT FROM AUTHOR]

Background: The external carotid artery (ECA) anastomoses in many distal territories supplied by the internal carotid artery (ICA) and is an important source of collateral circulation to the brain. Stenosis of the ECA in ipsilateral ICA occlusion can produce ischemic sequelae., Objective: To examine the effectiveness of ECA stenting in treating symptomatic ipsilateral ICA occlusion., Methods: We retrospectively reviewed patient databases from 5 academic medical centers to identify all individuals who underwent ECA stenting after 1998. For all discovered cases, coinvestigators used a common submission form to harvest relevant demographic information, clinical data, procedural details, and follow-up results for further analysis., Results: Twelve patients (median age, 66 years; range, 45-79 years) were identified for our cohort. Vessel disease involvement included severe ECA stenosis >or= 70% in 11 patients and ipsilateral ICA occlusion in all patients. Presenting symptoms included signs of transient ischemic attack, stroke, and amaurosis fugax. ECA stenting was associated with preservation of neurological status in 11 patients and resolution of symptoms in 5 patients at a median follow-up time of 26 months (range, 1-87 months; mean, 29 months). Symptomatic in-stent restenosis did not occur within any patient during the follow-up course., Conclusion: We found ECA stenting in symptomatic ipsilateral ICA disease to be a potentially effective strategy to preserve neurological function and to relieve ischemic symptoms. Further investigation with larger studies and longer follow-up periods is warranted to elucidate the true indications of this management strategy.

Objective: Currently, there is minimal published data on the use of heparin-coated stents in the neurovasculature; however, these stents have a proven clinical record in the treatment of coronary disease. This article details our experience with the safety and technical aspects of stent deployment in the first 10 patients who had heparin-coated stents placed in the intracranial and cervical vasculature and the preliminary follow-up in most cases., Methods: We retrospectively reviewed the clinical history, intra- and periprocedural data, and imaging for the patients who received heparin-coated stents in the cervical and intracranial vasculature for cerebrovascular disease between October 2002 and October 2003., Results: Thirteen heparin-coated stents were placed in 10 patients. Seven out of the 10 patients had heparin-coated stents placed in the posterior circulation; the remaining three patients had stents placed in the anterior circulation. Four patients had stents placed intracranially. There was no acute or subacute in-stent thrombosis and no procedure-related complications. Follow-up was performed on most patients, with no clinical symptoms attributable to restenosis in any patient., Conclusion: This small series suggests that heparin-coated stents are safe for use in the treatment of cervical and intracranial atherosclerotic disease. Longer-term follow-up is needed to study the heparin coating effect on in-stent restenosis rates and to assess the long-term durability and clinical efficacy of this stent. The use of drug-coated stents in the cerebrovascular circulation is an area that warrants further investigation.

We describe the case of an 82-year-old man with a fixed neurological deficit of 30 h duration. A left hemispheric perfusion deficit was found on perfusion/diffusion imaging studies in conjunction with an ipsilateral carotid stenosis documented by cerebral angiography. Carotid angioplasty with stent placement was performed and resulted in dramatic clinical improvement. Carotid stenosis can cause acute hemodynamic hypoperfusion with a symptomatic reversible clinical deficit.

Objective: To describe a novel application of the Neuroform stent (Boston Scientific-Target, Fremont, CA) for the management of eight wide-necked aneurysms., Methods: All patients were treated using a single Neuroform stent placed partially into the aneurysm and into the afferent artery. The portion of the stent protruding into the aneurysm fundus provided neck support for the subsequent successful coiling., Conclusion: The Neuroform stent is a versatile device that can be used in a variety of ways to assist in the coiling of wide-necked aneurysms. The technique described here may be used for bifurcation aneurysms in lieu of using two stents in a Y configuration.

Objective: In patients who are not candidates for intravenous tissue plasminogen activator, intra-arterial (IA) therapy is an alternative. Current recanalization rates are 50 to 60% for IA thrombolysis. Stent-assisted recanalization in the setting of acute stroke after failed thrombolysis may improve recanalization rates., Methods: A retrospective analysis was performed of 19 patients treated at two institutions between July 2001 and March, 2005 with intracranial stenting of a vessel resistant to standard thrombolytic techniques. Demographics, clinical, and radiographic presentation and outcomes were studied., Results: Thirteen men and six women with a median baseline National Institutes of Health Stroke Scale (NIHSS) score of 16 (range, 15-22) were included. Eight lesions were located at the internal carotid artery terminus, seven in the M1/M2 segment, and four in the basilar artery. Average time-to-treatment was 210 +/- 160 minutes. Overall recanalization rate (Thrombolysis in Cerebral Infarction Grade 2 or 3) was 79%. There were six deaths: five due to progression of stroke and withdrawal of care at the family's request and one as the result of a delayed carotid injury after tracheostomy. One postoperative asymptomatic intracranial hemorrhage occurred without adverse affect on outcome. Median discharge NIHSS score of surviving patients was 5 (range, 2.5-11.5). Lesions at the internal carotid artery terminus (P < 0.009), older age (P < 0.003), and higher baseline NIHSS score (P < 0.009) were significant negative outcome predictors, as measured by >3 modified Rankin scale score at discharge., Conclusion: Stent-assisted recanalization for acute stroke resulting from intracranial thrombotic occlusion is associated with a high recanalization rate and low intracranial hemorrhage rate. These initial results suggest that stenting may be an option for recalcitrant cerebral arterial occlusions.

Objective and Importance: Acute ischemic stroke is the third leading cause of death in the United States. For patients with NIHSS scores >10 and evaluated within 6 hours, intra-arterial thrombolysis is the treatment of choice. The Merci retriever (Concentric Medical Inc., Mountain View, CA) and IV TPA are currently the only FDA-approved treatments for acute ischemic stroke. For patients who do not meet the criteria for TPA administration and/or in whom the Merci device fails, options are limited. Intracranial stenting for acute ischemic stroke after failed thrombolysis is now possible because of improved delivery systems and appropriately sized stents., Clinical Presentation: A 26-year-old woman presented with an NIHSS score of 11 (right-sided hemiparesis and mixed aphasia) 4 hours from the time of symptom onset. CT perfusion demonstrated increased time to peak in the entire left hemisphere; conventional angiography demonstrated a left M1 occlusion., Intervention: After crossing the occlusion with a microcatheter, reteplase (2 units) was administered into the clot. Mechanical thrombolysis was then attempted, without restoration of flow. Two 3 x 12-mm coronary stents were placed from the M1 into the superior and inferior divisions, respectively, with complete restoration of flow (TIMI 3). Within 72 hours, the patient had an NIHSS score of 1, with a small infarction in the external capsule., Conclusion: Novel stroke interventions need to be developed for patients with acute ischemic stroke in whom traditional interventions fail. We present (to our knowledge) the first case of successful revascularization of an acute M1 occlusion accomplished with placement of two coronary stents.

Objective: Patients 80 years and older are generally considered to be at an increased risk for stroke and death from carotid endarterectomy. High-risk status often qualifies them for entry into a carotid angioplasty and stenting (CAS) trial. The aim of this study is to report periprocedure (0-30 d) morbidity and mortality among elderly patients undergoing CAS with and without distal embolic protection in an intention-to-treat analysis., Methods: A retrospective review was performed to evaluate the medical records and imaging studies of patients 80 years or older who underwent attempted CAS procedures with and without distal embolic protection between June 1996 and February 2004., Results: Ages of the 75 patients identified in our review ranged from 80 to 91 years (average 83.1 yr); 41 were men. Internal carotid artery stenosis ranged from 60 to 95% (mean 78.3%). Forty-two patients had symptoms (transient ischemic attack, 29; stroke, 13), and 33 patients were asymptomatic. Total event rates were major stroke, 4% (3 patients); minor stroke, 6.7% (5 patients); death, 4% (3 patients). Rates in the unprotected group (35 patients) were major stroke, 8.6% (3 patients); minor stroke, 5.7% (2 patients); major stroke/death, 14.3% (5 patients). Rates in the protected group (40 patients) were major stroke, 0; minor stroke, 7.5% (3 patients); major stroke/death, 0; (P < 0.05)., Conclusion: These results suggest that elderly patients undergoing CAS with adjunctive distal embolic protection are at a lower risk of periprocedure adverse events. Routine clopidogrel use, smaller hardware profile, patient selection, and increased experience likely contributed to these results.

We performed a preliminary feasibility and safety study using intravenous (IV) administration of a platelet glycoprotein IIb/IIIa inhibitor (abciximab) in conjunction with intraarterial (IA) administration of a thrombolytic agent (reteplase) in a primate model of intracranial thrombosis. We introduced thrombus through superselective catheterization of the intracranial segment of the internal carotid artery in 16 primates. The animals were randomly assigned to receive IA reteplase and IV abciximab ( n =4), IA reteplase and IV placebo ( n =4), IA placebo and IV abciximab ( n =4) or IA and IV placebo ( n =4). Recanalization was assessed by serial angiography during the 6-h period after initiation of treatment. Postmortem magnetic resonance (MR) imaging was performed to determine the presence of cerebral infarction or intracranial hemorrhage. Partial or complete recanalization at 6 h after initiation of treatment (decrease of two or more points in pre-treatment angiographic occlusion grade) was observed in two animals treated with IA reteplase and IV abciximab, three animals treated with IA reteplase alone and one animal treated with IV abciximab alone. No improvement in perfusion was observed in animals that received IV and IA placebo. Cerebral infarction was demonstrated on postmortem MR imaging in three animals that received IA and IV placebo and in one animal each from the groups that received IA reteplase and IV abciximab or IV abciximab alone. One animal that received IV abciximab alone had a small intracerebral hemorrhage on MR imaging. IA reteplase with or without abciximab appeared to be the most effective regimen for achieving recanalization in our model of intracranial thrombosis. Further studies are required in experimental models to determine the optimal dose, method of administration and efficacy of these medications in acute ischemic stroke.

Object: Animal aneurysm models are required for the study of the hemodynamics and pathophysiology of intracranial aneurysms in humans and so that experimental treatments can be tested prior to clinical trials. The authors developed a canine model that consistently produces up to three bifurcation aneurysms similar in morphological features and hemodynamics to human intracranial aneurysms., Methods: In 10 mongrel dogs, a harvested segment of the external jugular vein was anastamosed to an external carotid artery (CA)-lingual artery bifurcation arteriotomy site to create a lateral bifurcation aneurysm. The surgery was repeated on the contralateral side in each animal to form a second lateral bifurcation aneurysm and, in five dogs, a CA-CA crossover anastomosis was also performed to create a terminal bifurcation aneurysm. Nineteen of 20 lateral bifurcation aneurysms were confirmed in 10 dogs by diagnostic angiography 7 to 14 days after surgery. Aneurysm fundus-to-neck ratios ranged from 1 to 2, depending on the size of the arteriotomy. The terminal bifurcation aneurysms were confirmed in all five dogs by diagnostic angiography 7 to 14 days after the procedure. The authors later tested endovascular techniques for embolizing the aneurysms., Conclusions: Three bifurcation aneurysms of sufficient size for endovascular access can be created in a reproducible fashion in the same animal. This model is useful for studying complex endovascular procedures in aneurysms that mimic the human condition and for testing new devices and techniques.

During angiography, blood flow is visualized with a radiopaque contrast agent, which is denser than blood. In complex vasculature, such as cerebral saccular aneurysms, the density difference may produce an appreciable gravity effect, where the contrast material separates from blood and settles along the gravity direction. Although contrast settling has been occasionally reported before, the fluid mechanics behind it have not been explored. Furthermore, the severity of contrast settling in cerebral aneurysms varies significantly from case to case. Therefore, a better understanding of the physical principles behind this phenomenon is needed to evaluate contrast settling in clinical angiography. In this study, flow in two identical groups of sidewall aneurysm models with varying parent-vessel curvature was examined by angiography. Intravascular stents were deployed into one group of the models. To detect contrast settling, we used lateral view angiography. Time-intensity curves were analysed from the angiographic data, and a computational fluid dynamic analysis was conducted. Results showed that contrast settling was strongly related to the local flow dynamics. We used the Froude number, a ratio of flow inertia to gravity force, to characterize the significance of gravity force. An aneurysm with a larger vessel curvature experienced higher flow, which resulted in a larger Froude number and, thus, less gravitational settling. Addition of a stent reduced the aneurysmal flow, thereby increasing the contrast settling. We found that contrast settling resulted in an elevated washout tail in the time-intensity curve. However, this signature is not unique to contrast settling. To determine whether contrast settling is present, a lateral view should be obtained in addition to the anteroposterior (AP) view routinely used clinically so as to rule out contrast settling and hence to enable a valid time-intensity curve analysis of blood flow in the aneurysm.

Background and Purpose: The authors determined the technical success and the clinical and angiographic results of angioplasty and/or stent placement for intracranial atherosclerotic disease (ICAD) at a tertiary-care referral hospital., Methods: Angiographic and clinical outcomes occurring within the 1-month follow-up interval were recorded. Patients were followed up for a mean period of 20.5 +/- 9.2 months, and a neurovascular imaging study was performed in 18 of the 21 patients alive after a mean period of 19.7 +/- 9.2 months. Stroke-free survival and ipsilateral stroke-prevention rates were estimated using Kaplan Meier analyses., Results: Twenty-four patients (mean age = 61.0 +/- 13.5 years; 15 were men) underwent 30 procedures for treatment of ICAD. The procedures included angioplasty (n = 18) and attempted primary stent placement (n = 14). In 2 procedures, angioplasty was performed in the same session after unsuccessful stent placement. There was immediate stenosis reduction (mean +/- SD) from 84% +/- 17% to 27% +/- 21%. The overall 1-month composite rate of major stroke, death, and major bleeding complications was 7% for the 30 procedures. Overall stroke-free survival at 36 months was estimated as 79% (95% confidence interval, 57%-91%), and the ipsilateral stroke-prevention rate was estimated to be 87% (95% confidence interval, 65%-95%). Among the 15 patients who underwent repeat angiography, restenosis requiring second intervention was observed in 1 patient. No restenosis could be identified in 3 patients who underwent computed tomographic or magnetic resonance angiography., Conclusion: This single-center study demonstrates the feasibility and effectiveness (for secondary stroke prevention) of angioplasty and/or stent placement for treatment of ICAD.

Objectives: Daughter aneurysms have been strongly associated with saccular aneurysm rupture. We constructed a mathematical model to help explain this association as a possible hemodynamic mechanism for intracranial saccular aneurysm rupture., Methods: Our model is based on the assumption that when an aneurysm reaches a state of imminent rupture, the weakest area of the aneurysm wall responds passively to a surge of intra-aneurysmal pressure by forming a daughter aneurysm that will be the site of the eventual rupture. The daughter and parent aneurysms were assumed to be spherical. Using mathematical modeling, the growth of the daughter aneurysm was observed. To obtain the change in tensile stress in the daughter aneurysm wall under constant pressure and changing geometry, the Law of Laplace was applied to the parent and the daughter aneurysms., Results: The model reveals that the stress factor, i.e. tensile stress in the daughter aneurysm wall relative to the wall strength (rupture point), is dependent on two geometric parameters: the orifice factor (mu), which represents the relative size of the daughter aneurysm orifice radius to the parent aneurysm radius; and the aspect ratio (lambda), which represents the height-to-orifice ratio of the daughter aneurysm. As the daughter aneurysm develops, the stress factor first decreases to protect against rupture. Minimal stress is attained at an aspect ratio (lambda) of 0.577 regardless of the orifice factor. This is a relatively stable state. Further growth of the daughter aneurysm results in an increase of stress above the minimum, eventually leading to rupture at a stress factor of 1. A smaller orifice factor mu allows this aneurysm to grow to a higher aspect ratio lambda before rupture., Discussion: Daughter aneurysm formation is a likely path to aneurysm rupture. The formation of a daughter aneurysm temporarily decreases the tensile stress within a parent aneurysm in which rupture is imminent, indicating a temporary protective role of daughter aneurysm development. Aneurysms harboring daughter aneurysms are at a more advanced stage of development, hence at a greater risk for rupture. The severity of the rupture risk can be estimated on the basis of daughter aneurysm geometry; aspect ratio lambda > 0.577 indicates a greater risk of rupture. Furthermore, daughter aneurysms with larger orifices are associated with a greater risk of rupture.

The purpose of this article is to describe several inadvertent perforations of external carotid artery branches that occurred in our laboratory during planned carotid artery stenting procedures. When known, the mechanism of the perforation is described. The treatment of these complications is discussed, along with a more general discussion of potential embolic materials. Perforation of branch arteries within the external carotid artery territory during planned carotid revascularization is an uncommon but potentially life-threatening complication. This complication can occur as a result of wire or catheter placement into these vessels. Early recognition of the perforation, prompt treatment of the bleeding, and control of the patient's airway are necessary to avoid a potentially catastrophic outcome.

Vertebrobasilar nonsaccular aneurysms represent a small subset of intracranial aneurysms and usually are among the most challenging to be treated. The aim of this article was to review the literature and summarize the experience in the treatment of these lesions with endovascular approaches. The method of stent implantation as it is performed at the authors' institution, including options available for vertebral artery access, is described. Practitioners involved in the treatment of these lesions should be aware of the potential application of intravascular stent placement as well as the associated postprocedure risks and potential complications.

Objective: Cerebral blood flow (CBF) alterations are common after aneurysmal subarachnoid hemorrhage (SAH). Treatment of delayed cerebral ischemia in this setting depends on timely and accurate diagnosis. Techniques to measure cerebral blood flow are useful and important. Computed tomographic (CT) perfusion imaging is a technique for the measurement of CBF, cerebral blood volume, and time to peak. It is a fast and inexpensive brain imaging modality that offers promise in the management of patients with SAH., Methods: CT perfusion imaging was performed in 10 patients with aneurysmal SAH when neurological changes raised suspicions of cerebral ischemia. Quantitative values for CBF, cerebral blood volume, and time to peak were obtained in each study. The case history, CT perfusion results, and an analysis of how patient management was influenced are presented for each patient., Results: A total of 17 CT perfusion studies were performed. Five studies showed evidence of cerebral ischemia, leading to endovascular treatment of vasospasm. Eight studies excluded cerebral ischemia, and two studies identified cerebral hyperemia, resulting in adjustments in hyperdynamic therapy. CT perfusion was used to help predict a poor prognosis and withhold aggressive intervention in two patients with poor Hunt and Hess grades. Time-to-peak values identified regions of cerebral ischemia more readily than CBF or cerebral blood volume values., Conclusion: CT perfusion imaging can be used to identify patients with delayed cerebral ischemia after SAH and to guide medical and endovascular therapy. The findings can lead to alterations in patient management.

Recent advances in carotid artery (CA) stent placement procedures have propelled this technology into the forefront of treatment options for both symptomatic and asymptomatic patients with CA stenosis. Until recently, endarterectomy was the only surgical option for patients with CA occlusive disease. For high-risk surgical candidates, periprocedural stroke rates remained unacceptable and were significantly higher than those associated with the natural history of the disease. Advances in stent technology and improvements in antiplatelet and antithrombotic regimens, in conjunction with distal protection devices, have significantly lowered the risk of periprocedural complications for high-risk surgical candidates requiring CA revascularization. In this paper the authors review data gleaned from the important recent CA stent trials and address questions concerning the safety, efficacy, and durability of stent-assisted angioplasty for extracranial CA occlusive disease. Additionally, they review the role of noninvasive imaging modalities for the diagnosis and surveillance of CA disease in these high-risk patients.

Object: To determine the rate of hemodynamically significant recurrent carotid artery (CA) stenosis after stent-assisted angioplasty for CA occlusive disease, the authors analyzed Doppler ultrasonography data that had been prospectively collected between October 1998 and September 2002 for CA stent trials., Methods: Patients included in the study participated in at least 6 months of follow-up review with serial Doppler studies or were found to have elevated in-stent velocities (> 300 cm/second) on postprocedure Doppler ultrasonograms. Hemodynamically significant (> or = 80%) recurrent stenosis was identified using the following Doppler criteria: peak in-stent systolic velocity at least 330 cm/second, peak in-stent diastolic velocity at least 130 cm/second, and peak internal carotid artery/common carotid artery velocity ratio at least 3.8. Follow-up studies were obtained at approximate fixed intervals of 1 day, 1 month, 6 months, and yearly. Angiography was performed in the event of recurrent symptoms, evidence of hemodynamically significant stenosis on Doppler ultrasonography, or both. Treatment was repeated because of symptoms, angiographic evidence of severe (> or = 80%) recurrent stenosis, or both of these. Stents were implanted in 142 vessels in 138 patients (all but five patients were considered high-risk surgical candidates and 25 patients were lost to follow-up review). For the remaining 112 patients (117 vessels), the mean duration of Doppler ultrasonography follow up was 16.42+/-10.58 months (range 4-54 months). Using one or more Doppler criteria, severe (> or = 80%) in-stent stenosis was detected in six patients (5%). Eight patients underwent repeated angiography. Six patients (three with symptoms) required repeated intervention (in four patients angioplasty alone; in one patient conventional angioplasty plus Cutting Balloon angioplasty; and in one patient stent-assisted angioplasty)., Conclusions: In a subset of primarily high-risk surgical candidates treated with stent-assisted angioplasty, the rates of hemodynamically significant restenosis were comparable to surgical restenosis rates cited in previously published works. Treatment for recurrent stenosis incurred no instance of periprocedure neurological morbidity.

Computed tomography (CT) perfusion imaging is a technique for the measurement of cerebral blood flow, cerebral blood volume, and time-to-peak or mean transit time. The technique involves the administration of a single-bolus dose of iodinated contrast material, followed by spiral CT imaging during the passage of the contrast bolus through the cerebral vasculature. CT perfusion is a fast and inexpensive brain imaging modality for use in the management of patients with various neurological disorders, ranging from acute stroke to subarachnoid hemorrhage. This article reviews the technique of CT perfusion and presents several illustrative cases in which this imaging modality was used effectively in the critical care of patients with neurological disorders.

Introduction: Cerebral vasospasm in aneurysmal subarachnoid hemorrhage (SAH) is associated with poor outcome. The safety and feasibility of continuous high-dose intravenous magnesium sulfate (MgSO4) for the prevention of cerebral vasospasm and ischemic cerebral injury has not been well studied., Methods: Patients presenting to our center within 72 hours of aneurysmalSAH (confirmed by computed tomography [CT] scanning and cerebral angiography) between June 2001 and October 2002 were enrolled in a prospective pilot study in which they received MgSO4 as an adjunct to standard SAH management. Study patients received an intravenous infusion of 12 g of MgSO4 in a 500-mL solution of 0.9% NaCl administered at a rate of 4.06 mM (or 0.5 g) every hour over a 24-hour period for 10 days to achieve a target predetermined serum Mg range of more than 1.5 to less than 4.0 mM/L. The effect of MgSO4 on clinical examination, heart rate, and blood pressure was measured every 2 hours; serum glucose and phenytoin levels were monitored daily. Outcome measures included evidence of vasospasm on clinical examination, transcranial Doppler study ((TCD); velocity >or=100 cm/s), or repeat cerebral angiogram obtained within 10 days of SAH; and Glasgow Outcome Scale (GOS) score assessment and CT scan evidence of ischemic infarction at 30 days., Results: Nineteen patients (mean age: 55 years; range: 39-84 years; 11 males, 8 females) were enrolled in the study. Presenting Hunt Hess grade was II or higher; mean Fisher grade was 3. Vasospasm was observed in nine patients (by clinical examination in two, TCD in five, and angiogram in nine). The mean serum Mg level was 2.7 mM/L (standard deviation: +/- 0.37) and was maintained during the infusion period. No clinical adverse effects, hemodynamic changes, or fluctuations in serum glucose or phenytoin levels were observed. None of the patients died; no CT evidence of ischemic infarction was present; and most had good outcomes (GOS 5 in 10 patients; GOS 4 in 8 patients)., Conclusion: Our study confirmed the safety and feasibility of a continuous infusion of high-dose intravenous MgSO4 in patients with aneurysmal SAH. Randomized controlled trials are required to confirm the promising results.

More than 750,000 strokes occur annually in the United States. Of these, 8-10% are due to intracranial atherosclerosis. Less than 50% of patients with strokes from intracranial atherosclerosis will have a transient ischemic attack. For those patients with symptomatic intracranial atherosclerosis, the prognosis is poor; and the recent Warfarin-Aspirin Symptomatic Intracranial Stenosis (WASID) trial results have demonstrated the high risk of warfarin without clear benefit. Intracranial angioplasty and stenting is emerging as a viable and effective treatment alternative for patients with symptomatic intracranial stenosis. Advances in stent design, endovascular wires, and catheters and balloons are allowing endovascular surgeons to safely treat intracranial atherosclerosis. Wider clinical experience has led to refinement of patient selection and endoluminal techniques. Drug eluting-stents have the promise of decreasing the risk of restenosis. In this review, the most recent clinical, laboratory, and technical details for the treatment of intracranial angioplasty and stenting are discussed.

Introduction: Severe medically refractory intracranial stenosis portends a grave prognosis. Recent advances in stent technology have enabled clinicians to treat these lesions. Evidence in the coronary literature suggests that stenting without predilation angioplasty is as safe and effective as stenting immediately preceded by predilation angioplasty for the treatment of severely stenotic lesions. Because of marked differences in vessel histology and differences in the sensitivity of the cerebral and coronary vascular beds to embolic insult, direct stenting of severe intracranial stenoses may be more prone to neurological complications than a conventional or staged stenting procedure., Methods: We reviewed our clinical experience with conventional, direct, and staged stenting for high-grade stenoses involving the posterior intracranial circulation. We also reviewed the literature and experimental data supporting the rationale for staged stenting., Results: In our experience, no permanent neurological morbidity was identified in four patients treated with a staged approach. In contrast, one of three patients with conventional stenting of the basilar artery and two of four patients treated with direct basilar stenting had permanent neurological sequelae., Conclusion: For patients with high-grade posterior circulation intracranial stenoses involving the perforator-rich zones of the basilar artery, staged stenting may reduce procedure-related morbidity. A staged approach allows for plaque stabilization resulting from post-angioplasty fibrosis, which may protect patients from "snow-plowing," embolic shower of debris, or dissection. Further clinical, in vivo, and histological investigation is warranted.

Cervical carotid stenosis is a major cause of stroke and disability. Although carotid endarterectomy is an established and effective treatment for some patients with carotid artery stenosis, angioplasty and stenting has emerged in recent years as a viable alternative, particularly for patients who may be less suited for surgery. This article reviews patient selection for the two alternative approaches. The authors review the findings of the major clinical trials of carotid endarterectomy, summarize the development of carotid angioplasty and stenting, and identify patient characteristics that may guide selection of surgical or endovascular treatment.

The use of stents in the intracranial circulation has been made possible by rapid developments in stent technology in recent years. Considerable improvements in stent design, delivery devices, and technique have expanded the use of stenting to the treatment of intracranial disorders. This article reviews the indications for endovascular stenting for cerebral aneurysms and intracranial atherosclerosis and describes the peri-procedure management and technique applied at the Department of Neurosurgery at the University at Buffalo.

Background: Parent vessel thrombus formation is a serious complication of intracranial aneurysm embolization. The management of this issue is controversial. Abciximab, a potent platelet inhibitor, has been shown to have thrombolytic effects during coronary interventions. A small number of cases have demonstrated its potential application in neuroendovascular procedures. We review the literature on the management of parent vessel thrombosis during aneurysm coil embolization and report our successful experience with the use of IV abciximab to treat parent vessel thrombus formation related to coil embolization of a basilar apex aneurysm., Case Description: A 45-year-old man presented to our center with an incidental basilar apex aneurysm. After being informed of the surgical and endovascular treatment options, he elected to undergo coil embolization of the aneurysm. During the procedure, acute thrombus was noted in the left P1 segment of the posterior cerebral artery. IV abciximab was administered, and an angiogram the following day showed complete dissolution of the clot. The patient had no neurologic sequelae., Conclusions: IV abciximab appears to be an effective option in the management of acute parent vessel thrombus encountered during coil embolization of unruptured aneurysms. Sufficient data are lacking regarding its use in the setting of a ruptured aneurysm.

Object: Few researchers have quantified the role of arterial geometry in the pathogenesis of saccular cerebral aneurysms. The authors investigated the effects of parent artery geometry on aneurysm hemodynamics and assessed the implications relative to aneurysm growth and treatment effectiveness., Methods: The hemodynamics of three-dimensional saccular aneurysms arising from the lateral wall of arteries with varying arterial curves (starting with a straight vessel model) and neck sizes were studied using a computational fluid dynamics analysis. The effects of these geometric parameters on hemodynamic parameters, including flow velocity, aneurysm wall shear stress (WSS), and area of elevated WSS during the cardiac cycle (time-dependent impact zone), were quantified. Unlike simulations involving aneurysms located on straight arteries, blood flow inertia (centrifugal effects) rather than viscous diffusion was the predominant force driving blood into aneurysm sacs on curved arteries. As the degree of arterial curvature increased, flow impingement on the distal side of the neck intensified, leading to elevations in the WSS and enlargement of the impact zone at the distal side of the aneurysm neck., Conclusions: Based on these simulations the authors postulate that lateral saccular aneurysms located on more curved arteries are subjected to higher hemodynamic stresses. Saccular aneurysms with wider necks have larger impact zones. The large impact zone at the distal side of the aneurysm neck correlates well with other findings, implicating this zone as the most likely site of aneurysm growth or regrowth of treated lesions. To protect against high hemodynamic stresses, protection of the distal side of the aneurysm neck from flow impingement is critical.

Object: Use of the sirolimus-eluting stent has led to a reduction of in-stent stenosis following treatment of coronary atherosclerosis, whereas treatment of intracranial atherosclerosis with bare-metal stents results in excessive restenosis rates of approximately 40%. Neurotoxicity effects and vessel injury are unknown in the cerebral vasculature. To assess the safety profile and vascular effects of sirolimus-coated stents, the authors conducted a prospective comparative study in which drug-eluting and bare-metal stents were implanted in the canine basilar artery (BA)., Methods: Sixteen mongrel dogs were randomized (eight animals per group) to receive either bare-metal 1.5 x 8-mm (six-cell) stents or sirolimus-eluting stents of the same dimensions. Interventionists, histopathologists, and histopathology technicians who participated in the study were blinded to the stent characteristics. Stents were implanted in the canine BA. Serial peripheral blood samples were obtained during the 1st week after implantation to determine the time-dependent serum concentration of sirolimus. Follow-up angiographic studies were performed 30 days after stent implantation to assess the effects of stent placement on the BA and brainstem perforating vessels. Explantation of the stent and BA was performed immediately after angiography by using a pressurized formalin fixation procedure. Histological and computer-assisted morphometric analyses of specimens obtained in each animal were performed. Sirolimus could not be detected in peripheral blood samples obtained later than 24 hours posttreatment. On follow-up angiography, all perforating vessels observed on initial angiograms remained patent, and no evidence of parent vessel damage or pseudoaneurysm formation was observed. Explanted vessels and brainstem sections did not demonstrate evidence of histological neurotoxicity, such as gliosis or infarction. No significant differences were found in the time to endothelialization of bare-metal and sirolimus-coated stents. Smooth-muscle cell (SMC) proliferation, the putative agent for restenosis, was lower in animals receiving sirolimus-coated stents (p = 0.003). Additionally, intimal fibrin density was increased in the dogs treated with sirolimus-coated stents (p < 0.0001). Histological evidence of an inflammatory response demonstrated a trend toward a reduced response in the sirolimus group (mean 0.58) compared with the bare-metal group (mean 0.83, p = 0.33)., Conclusions: No neurotoxic effects were observed in the intracranial vessel walls or brainstem tissue in which sirolimus-coated stents were implanted. Compared with bare-metal stents, the sirolimus-coated devices did not impair endothelialization and, furthermore, tended to reduce the proliferation of SMCs. These findings indicate that sirolimus-coated devices may inhibit in-stent stenosis. Further studies with longer-term follow up are required to assess the restenosis rates of sirolimus-coated stents implanted in the intracranial vasculature.

Dye-dilution imaging sequences were performed and time-density curves were constructed in elastomer vessel aneurysm models to demonstrate the effectiveness of coils and an asymmetric stent in disrupting standard vortex flow. Compared with the use of coils, the use of stents led to marked flow modification, as seen with imaging sequences, and substantially slower inflow, as indicated by time-density curves, owing to the low-porosity region of the stent that covers the aneurysm orifice. These flow examination results indicate that potentially favorable flow modification features can be created by using the described asymmetric stent design, the use of which may lead to alternative methods of image-guided endovascular cerebral aneurysm therapy., (Copyright RSNA, 2004)

Neuroendovascular surgery is a rapidly evolving field. Each year, numerous improvements are made in the endovascular surgeon's armamentarium. This evolution in technology, which is occurring at a dizzying pace, addresses many of the current limitations of neuroendovascular approaches. The potential to improve the outcomes of our patients is tremendous, particularly because one of the most common and most devastating neurological disorders, ischemic stroke, remains largely untreated. This article presents several of the new technologies that are currently being investigated or are under development and have the potential to lead to major advances in endovascular approaches for the treatment of intracranial and extracranial diseases.

Background and Purpose: To develop a technique for site-specific placement of a thrombus of predetermined volume in an animal model for the purpose of evaluating methods of intravascular thrombolysis and clot retrieval., Methods: Six swine were subjected to thrombus injection bilaterally in the ascending pharyngeal artery (APA). Each animal underwent transfemoral angiography while under general anesthesia. A nondetachable balloon catheter and a 3-French microcatheter were then advanced into the common carotid artery through a 7-French guide catheter. With the microcatheter in the proximal APA and the balloon inflated proximally, a bolus of preformed thrombus composed of 0.9 mL of autologous blood and 0.1 mL of bovine thrombin (200 IU/mL) was injected through the microcatheter while local flow arrest was maintained for 15 min. The balloon was deflated and removed. The occluded arteries were observed by serial angiography for 3 hr and then resected for gross examination and hematoxylin and eosin staining., Results: Each APA was occluded angiographically and did not recanalize during the 3-hr observation period. Persistent, proximal progression of thrombus to the superior thyroid artery origin occurred in three animals. Gross inspection revealed that the resected arteries contained thrombus in the proximal APA but not in the common carotid artery. Histologic examination revealed organized thrombus, without evidence of intimal injury., Conclusion: Our model provides a simple, reliable method for site-specific injection of a thrombus of predetermined volume. Site-specific placement is important for evaluation of the efficacy of thrombolytic agents and techniques. Angiographic evidence of brain revascularization can be used to grade revascularization and clot volume. The ability to specifically localize and estimate clot volume makes our model well suited for the evaluation and comparison of thrombolytic agents and endovascular techniques.

Background: Patients with unruptured intracranial aneurysms often present with headaches., Objective: To determine the effect of endovascular treatment on the character and frequency of headaches in patients with unruptured intracranial aneurysms., Methods: We reviewed the medical records of all patients who underwent endovascular treatment for unruptured intracranial aneurysms within a 9.5-year period. These patients were mailed a standard questionnaire in which they were asked about the frequency and character of any headache experienced before or after (or both) endovascular treatment. They were also asked to grade improvement or worsening of headaches after the procedure as mild (activities of daily living were not affected), moderate (activities of daily living were affected), or significant (the change resulted in an ability to perform new activities of daily living or an inability to perform previous activities of daily living)., Results: Forty-seven patients with unruptured aneurysms who underwent Guglielmi detachable coil embolization responded to the questionnaire. Of these, 32 patients (mean age, 52.7 years [SD, 13.4]; 22 were women) had experienced headaches before the procedure. Nineteen patients (59%) reported improvement in severity of headaches after embolization. Improvement was graded as significant by 7 patients, moderate by 8, and mild by 4. Two patients (6%) reported worsening severity of headaches graded as moderate. Five of 15 patients without headaches before embolization reported onset of mild (n = 4) or severe (n = 1) headaches after treatment., Conclusion: Guglielmi detachable coil embolization of unruptured intracranial aneurysms was associated with reduction in severity of headaches in the majority of patients who had experienced preprocedural headaches.

Object: Medically refractory, symptomatic atherosclerotic disease of the basilar artery (BA) portends a poor prognosis. Studies have shown morbidity rates following placement of stents in these lesions to be quite variable, ranging from 0 to 30%. The authors review their experience with BA stent placement for severe atherosclerotic disease to determine whether an increase in neurological morbidity is associated with direct stent placement (that performed without predilation angioplasty) compared with conventional stent placement (that performed immediately after predilation angioplasty) or staged stent placement (angioplasty followed > or = 1 month later by stent placement with or without repeated angioplasty)., Methods: The authors retrospectively reviewed the medical records from a consecutive series of 10 patients who underwent stent placement for medically refractory, symptomatic atherosclerotic disease of the BA between February 1999 and November 2002. Patient records were analyzed for symptoms at presentation, percentage of angiographically visible stenosis, devices used, procedure-related morbidity, and clinical and radiographic outcomes. Patients with symptomatic intracranial vertebral artery stenosis but without concomitant severe (> 50%) BA stenosis were excluded from the study. Four patients were treated with direct stent placement, three with a staged procedure (these were included in a previous publication), and three with conventional stent placement. In the group treated with direct stent placement, a dense quadriparesis developed in two patients after the procedure. Computerized tomography or magnetic resonance imaging revealed infarction of the ventral pons in these patients. In the staged stent placement group, no permanent neurological complications occurred after the procedure and, in the conventional stent placement group, one of three patients experienced a neurological complication involving homonymous hemianopsia., Conclusions: Direct stent placement in the BA is associated with a relatively high complication rate, compared with a staged procedure. Complications may result from an embolic shower following disruption of atheromatous plaque debris attained using high-profile devices such as stents, as demonstrated by the postoperative imaging appearance of acute pontine infarctions. Additionally, displacement of debris by the stent into the ostia (snowplowing) of small brainstem perforating vessels may be responsible for the complications noted. Although direct stent placement in peripheral and coronary vessels has been shown to be safe, the authors suggest that direct stent placement in the BA should be avoided to minimize the risk of periprocedure morbidity.

Objective and Importance: We describe a case of endoluminal stent placement for a cervical internal carotid artery stenosis in which percutaneous access was obtained via the radial artery., Clinical Presentation: A 69-year-old man with known disease of the carotid, peripheral, and coronary arteries as well as chronic obstructive pulmonary disease presented for endoluminal revascularization of a severe, progressive right internal carotid artery stenosis., Technique: Transfemoral access was complicated by the previous placement of a synthetic graft as the result of a previous right-to-left iliofemoral artery bypass procedure and an aortoiliac occlusion. A transradial approach was successfully attempted, and a Precise stent (Cordis Endovascular, Miami Lakes, FL) was successfully placed through a 6-French guide sheath., Conclusion: The transradial approach is becoming an increasingly viable alternative route for stent placement in patients with contraindicated or complicated femoral access routes. As devices become increasingly more pliable and smaller, the transradial route will be used with increasing frequency in this select patient population for stenting of both the cervical and intracranial circulation.

Objective: One concern with respect to stent procedures performed to treat patients with intracranial lesions is the fate of normal major arterial branches after stents are placed across them. Because most of these lesions occur at vessel bifurcations or at branch points, a normal major branch often arises near the lesion and may be difficult to avoid during stent positioning. The aim of this article is to describe the angiographic outcome of intracranial major branch arteries crossed by a stent in the intracranial circulation., Methods: We examined the immediate postprocedural cerebral angiograms of the 40 patients who underwent intracranial stenting at the University at Buffalo, Buffalo, NY, between June 1998 and April 2000. In each of 10 patients, the stent was placed across a normal major branch artery. Stents were used to treat aneurysms in seven patients and intracranial stenosis in three patients. The latest cerebral angiogram available was reviewed, and the patency of the major branch arteries was evaluated., Results: The angiographic follow-up period ranged from 4 days to 35 months (mean follow-up, 10 mo). Each of the 10 major branch arteries was patent. No infarcts were associated with the territory of the major branch arteries crossed by the stents, and no patient experienced a related episode of clinical ischemia. Four patients died as a result of causes unrelated to the stenting procedure. The histology of a middle cerebral artery stent that was placed across a lenticulostriate perforator is presented., Conclusion: The flexible, low-profile stents used in this study had no angiographically or clinically apparent effect on the major intracranial branches across which they were placed.

The authors report a case of an iatrogenic carotid-cavernous fistula (CCF) associated with intracranial angioplasty. Angioplasty was performed using a 3 x 10-mm Open Sail coronary balloon in a patient with high-grade stenosis of the left cavernous internal carotid artery (ICA). After angioplasty, a perforation developed in the cavernous ICA, resulting in a CCF. A 3.5 x 9-mm S670 coronary stent was used to treat the fistula. To the authors' knowledge, this is the first reported case in which a CCF developed after angioplasty was performed using a coronary balloon. Long-term angiographic and clinical evaluation is needed to test the suitability and durability of intracranial angioplasty and stent placement in the treatment of symptomatic intracranial stenosis.

Objective: The goals of this study were to identify and quantify the presence of programmed cell death (apoptosis) in intracerebral hemorrhage (ICH) among human subjects. Recent evidence from laboratory models suggests that cell death in the perihematoma region may involve apoptosis., Methods: Retrospective clinical and histological analyses were performed for patients with spontaneous ICH who underwent surgical evacuation. Quantification of apoptotic cells was performed in sections obtained from the perihematoma region from 12 patients with ICH and stained with the terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick-end labeling method. Necrosis was identified on the basis of morphological criteria, using hematoxylin and eosin staining., Results: Evidence of apoptosis was present in surgical specimens obtained from 10 of the 12 patients. The mean number of apoptotic cells in the perihematoma region in each patient specimen was 38% (range, 0-90%). For five patients, more than one-half of the total cells observed were apoptotic. Apoptosis was observed in specimens obtained within 1 day, 2 days, and 5 days after the onset of symptoms. No terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick-end labeling-positive cells were observed in specimens from the two patients with cerebellar hematomas. The mean proportion of necrotic cells in the perihematoma region in each patient specimen was 25% (range, 0-100%). There was a prominent excess of apoptotic cells, in comparison with necrotic cells, for 6 of the 12 patients who underwent hematoma evacuation. For five other patients, similar proportions of apoptotic and necrotic cells were observed. Necrosis was the predominant finding for only one patient, who underwent late surgical evacuation on Day 5., Conclusion: These observations suggest that apoptosis represents a prominent form of cell death associated with ICH in the perihematoma region. Further studies are required to define the mediators of apoptosis in ICH.