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Dive into the research topics where R. Webster Crowley is active.

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Featured researches published by R. Webster Crowley.


Stroke | 2011

Angiographic Vasospasm Is Strongly Correlated With Cerebral Infarction After Subarachnoid Hemorrhage

R. Webster Crowley; Ricky Medel; Aaron S. Dumont; Don Ilodigwe; Neal F. Kassell; Stephan A. Mayer; Daniel Ruefenacht; Peter Schmiedek; Stephan Weidauer; Alberto Pasqualin; R. Loch Macdonald

Background and Purpose— The long-standing concept that delayed cerebral infarction after aneurysmal subarachnoid hemorrhage results exclusively from large artery vasospasm recently has been challenged. We used data from the CONSCIOUS-1 trial to determine the relationship between angiographic vasospasm and cerebral infarction after subarachnoid hemorrhage. Methods— We performed a post hoc exploratory analysis of the CONSCIOUS-1 data. All patients underwent catheter angiography before treatment and 9±2 days after subarachnoid hemorrhage. CT was performed before and after aneurysm treatment, and 6 weeks after subarachnoid hemorrhage. Angiograms and CT scans were assessed by centralized blinded review. Angiographic vasospasm was classified as none/mild (0%–33% decrease in arterial diameter), moderate (34%–66%), or severe (≥67%). Infarctions were categorized as secondary to angiographic vasospasm, other, or unknown causes. Logistic regression was conducted to determine factors associated with infarction. Results— Complete data were available for 381 of 413 patients (92%). Angiographic vasospasm was none/mild in 209 (55%) patients, moderate in 118 (31%), and severe in 54 (14%). Infarcts developed in 6 (3%) of 209 with no/mild, 12 (10%) of 118 patients with moderate, and 25 (46%) of 54 patients with severe vasospasm. Multivariate analysis found a strong association between angiographic vasospasm and cerebral infarction (OR, 9.3; 95% CI, 3.7–23.4). The significant association persisted after adjusting for admission neurological grade and aneurysm size. Method of aneurysm treatment was not associated with a significant difference in frequency of infarction. Conclusions— A strong association exists between angiographic vasospasm and cerebral infarction. Efforts directed at further reducing angiographic vasospasm are warranted.


Stroke | 2009

Influence of Weekend Hospital Admission on Short-Term Mortality After Intracerebral Hemorrhage

R. Webster Crowley; Hian K. Yeoh; George J. Stukenborg; Ricky Medel; Neal F. Kassell; Aaron S. Dumont

Background and Purpose— There is expanding literature to show that certain patients admitted during the weekend have worse outcomes than similar patients admitted during the week. Although many clinicians have hypothesized the presence of this “weekend effect” with patients with intracerebral hemorrhage, there is a paucity of studies validating this conjecture. Methods— We performed a retrospective cohort study of patients with intracerebral hemorrhage (International Classification of Diseases, 9th Revision, Clinical Modification=431) extracted from the 2004 Nationwide Inpatient Sample. Multivariable logistic regression analyses and Cox proportional hazards regression were conducted to calculate the odds of death (within 7, 14, and 30 days) and the hazard ratio of death for patients with weekend intracerebral hemorrhage admissions compared with weekday intracerebral hemorrhage admissions. All analyses were adjusted for concurrent differences in length of stay, patient demographics, and comorbid disease. Results— Weekend hospital admissions accounted for 26.8% of the 13 821 patients with a diagnosis of intracerebral hemorrhage in the National Inpatient Sample. Admission during the weekend was a statistically significant independent predictor of death within 7 days (OR, 1.14; 95% CI, 1.05 to 1.25), within 14 days (OR, 1.15; 95% CI, 1.05 to 1.25), and within 30 days (OR, 1.15; 95% CI, 1.05 to 1.25). The adjusted hazard of in-hospital death (hazard ratio, 1.12; CI, 1.05 to 1.20) indicates that the overall risk of in-hospital death with intracerebral hemorrhage is 12% higher with weekend admission. Conclusion— Weekend admission for intracerebral hemorrhage was associated with increased risk-adjusted mortality when compared with admission during the remainder of the week.


Drug Discovery Today | 2008

New insights into the causes and therapy of cerebral vasospasm following subarachnoid hemorrhage

R. Webster Crowley; Ricky Medel; Neal F. Kassell; Aaron S. Dumont

Cerebral vasospasm lingers as the leading preventable cause of death and disability in patients who experience aneurysmal subarachnoid hemorrhage. Despite the potentially devastating consequences of cerebral vasospasm, the mechanisms behind it are incompletely understood. Nitric oxide, endothelin-1, bilirubin oxidation products and inflammation appear to figure prominently in its pathogenesis. Therapies directed at many of these mechanisms are currently under investigation and hold significant promise for an ultimate solution to this substantial problem.


Neurology | 2015

Endovascular vs medical management of acute ischemic stroke

Ching-Jen Chen; Dale Ding; Robert M. Starke; Prachi Mehndiratta; R. Webster Crowley; Kenneth C. Liu; Andrew M. Southerland; Bradford B. Worrall

Objective: To compare the outcomes between endovascular and medical management of acute ischemic stroke in recent randomized controlled trials (RCT). Methods: A systematic literature review was performed, and multicenter, prospective RCTs published from January 1, 2013, to May 1, 2015, directly comparing endovascular therapy to medical management for patients with acute ischemic stroke were included. Meta-analyses of modified Rankin Scale (mRS) and mortality at 90 days and symptomatic intracranial hemorrhage (sICH) for endovascular therapy and medical management were performed. Results: Eight multicenter, prospective RCTs (Interventional Management of Stroke [IMS] III, Local Versus Systemic Thrombolysis for Acute Ischemic Stroke [SYNTHESIS] Expansion, Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy [MR RESCUE], Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands [MR CLEAN], Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness [ESCAPE], Extending the Time for Thrombolysis in Emergency Neurological Deficits–Intra-Arterial [EXTEND-IA], Solitaire With the Intention For Thrombectomy as Primary Endovascular Treatment [SWIFT PRIME], and Endovascular Revascularization With Solitaire Device Versus Best Medical Therapy in Anterior Circulation Stroke Within 8 Hours [REVASCAT]) comprising 2,423 patients were included. Meta-analysis of pooled data demonstrated functional independence (mRS 0–2) at 90 days in favor of endovascular therapy (odds ratio [OR] = 1.71; p = 0.005). Subgroup analysis of the 6 trials with large vessel occlusion (LVO) criteria also demonstrated functional independence at 90 days in favor of endovascular therapy (OR = 2.23; p < 0.00001). Subgroup analysis of the 5 trials that primarily utilized stent retriever devices (≥70%) in the intervention arm demonstrated functional independence at 90 days in favor of endovascular therapy (OR = 2.39; p < 0.00001). No difference was found for mortality at 90 days and sICH between endovascular therapy and medical management in all analyses and subgroup analyses. Conclusions: This meta-analysis provides strong evidence that endovascular intervention combined with medical management, including IV tissue plasminogen activator for eligible patients, improves the outcomes of appropriately selected patients with acute ischemic stroke in the setting of LVO.


Journal of Neurosurgery | 2009

Endovascular obliteration of an intracranial pseudoaneurysm: the utility of Onyx.

Ricky Medel; R. Webster Crowley; D. Kojo Hamilton; Aaron S. Dumont

Pseudoaneurysms are rare lesions with a multitude of causes, including infectious, traumatic, and iatrogenic origins. In addition, there are a number of potential treatment options, all of which require consideration to determine the most appropriate management. Historically, surgical intervention has been the method of choice, but because the histopathological features of these lesions make them largely unsuitable for clipping, trapping or excision is often required. More recently endovascular methods have been used, including coil embolization, stent reconstruction, or parent artery occlusion. Although these methods are often successful, situations arise in which they are not technically feasible. The authors describe such a case in a pediatric patient with an iatrogenic pseudoaneurysm. Onyx was used to embolize the lesion and the results were excellent.


Stroke | 2010

Endovascular Treatment or Neurosurgical Clipping of Ruptured Intracranial Aneurysms. Effect on Angiographic Vasospasm, Delayed Ischemic Neurological Deficit, Cerebral Infarction, and Clinical Outcome

Aaron S. Dumont; R. Webster Crowley; Stephen J. Monteith; Don Ilodigwe; Neal F. Kassell; Stephan A. Mayer; Daniel Ruefenacht; Stephan Weidauer; Alberto Pasqualin; R. Loch Macdonald

Background and Purpose— The effects of aneurysm treatment modality (clipping or coiling) on the incidence of cerebral vasospasm and infarction after subarachnoid hemorrhage have not been clearly defined. We hypothesized that there may be a difference in angiographic and clinical vasospasm, cerebral infarction, and clinical outcome between patients undergoing clipping compared to coiling. Methods— A retrospective, exploratory analysis of 413 patients randomized into the CONSCIOUS-1 trial was conducted. Patients underwent baseline and follow-up catheter angiography and computed tomography, as well as clinical assessments. Radiology end points were adjudicated by central blinded review, and angiographic vasospasm was quantified by measurements of arterial diameters on catheter angiography. The effect of method of aneurysm treatment (clipping [n=199] or coiling [n=214]) on angiographic vasospasm, delayed ischemic neurological deficit, cerebral infarction, and clinical outcome was analyzed using univariate and multivariate logistic regression. Propensity matching was used to adjust for differences in baseline risk factors between clipped and coiled patients. Results— In all patients and the propensity-matched subset, aneurysm coiling was associated with a significantly reduced risk of angiographic vasospasm and delayed ischemic neurological deficit compared to clipping. Cerebral infarction and clinical outcome were not associated with clipping or coiling. Conclusions— In this exploratory analysis, aneurysm coiling was associated with less angiographic vasospasm and delayed ischemic neurological deficit than surgical clipping, whereas no effect on cerebral infarction or clinical outcome was observed. Whether this is attributable to differences in baseline risk factors between clipped and coiled patients or a true difference cannot be proven here.


Journal of Neurosurgery | 2009

Endovascular treatment of a fusiform basilar artery aneurysm using multiple in-stent stents : Technical note

R. Webster Crowley; Avery J. Evans; Neal F. Kassell; Mary E. Jensen; Aaron S. Dumont

Fusiform aneurysms of the basilar artery present difficult challenges for the treating physician. On one hand, these aneurysms are difficult and dangerous to treat. On the other, the relatively high rupture rate, risk of thromboemboli, and the frequent presence of mass effect on the brainstem often demand treatment rather than observation. While conservative treatment may be reasonable in an elderly patient, the relative resiliency and the larger lifetime cumulative risks of pediatric patients are compelling arguments for treatment. With the advancement of endovascular techniques some of these lesions have become treatable without the high morbidity and mortality rates associated with open surgical treatment, albeit with risks of their own. The authors present the case of a fusiform aneurysm arising from a severely tortuous basilar artery in a 22-month-old boy. The aneurysm was successfully treated using flow diversion by placing multiple intracranial stents without coil embolization. This allowed for thrombosis of the aneurysm and resolution of the mass effect on the brainstem without compromising blood flow to the brainstem.


BioMed Research International | 2013

Role of Stenting for Intracranial Atherosclerosis in the Post-SAMMPRIS Era

Dale Ding; Robert M. Starke; R. Webster Crowley; Kenneth C. Liu

Introduction. The initial promise of endovascular stenting for the treatment of intracranial atherosclerotic disease (ICAD) has been tempered by the results of the SAMMPRIS trial which demonstrated better outcomes with medical management compared to stenting for symptomatic ICAD. We review post-SAMMPRIS ICAD stenting outcomes. Methods. A comprehensive literature search was performed using PubMed to identify all ICAD stenting series published after the SAMMPRIS in September 2011. The type and design of the stent, number of patients and lesions, inclusion criteria, and clinical and angiographic outcomes were noted. Results. From October 2011 to August 2013, 19 ICAD stenting series were identified describing the interventional outcomes for 2,196 patients with 2,314 lesions. Of the 38 different stents used, 87% were balloon-expandable stents (BESs) and 13% were self-expanding stents. The median minimum stenosis was 50%. The median rates of technical success rate, postprocedural ischemic events, and symptomatic in-stent restenosis (ISR) were 98% (range 87–100%), 9.4% (range 0–25%), and 2.7% (range 0–11.1%), respectively. The median follow-up durations were one to 67 months. Conclusions. The management of severe ICAD remains controversial. Future trials are needed to define the optimal patient, lesion, and stent characteristics which will portend the best outcomes with intervention.


Neurosurgical Focus | 2009

Hyperperfusion syndrome following endovascular cerebral revascularization.

Ricky Medel; R. Webster Crowley; Aaron S. Dumont

Endovascular cerebral revascularization is becoming a frequently used alternative to surgery for the treatment of atherosclerotic disease, especially in the intracranial circulation where options are limited. Recent literature regarding the equivalent efficacy of carotid artery stenting and carotid endarterectomy in certain patient populations, as well as the recognition of the significant risk for recurrent stroke posed by intracranial lesions, will only serve to amplify this trend. Hyperperfusion syndrome has been well documented in the setting of carotid endarterectomy; however, a paucity of literature exists regarding the incidence, pathophysiology, and management as it relates to percutaneous interventions. The purpose of this review is to outline the current state of knowledge, with particular attention to the distinct attributes of endovascular treatment that would be expected to modify the course of hyperperfusion syndrome.


The Scientific World Journal | 2015

Endovascular Treatment of Venous Sinus Stenosis in Idiopathic Intracranial Hypertension: Complications, Neurological Outcomes, and Radiographic Results

Robert M. Starke; Tony R. Wang; Dale Ding; Christopher R. Durst; R. Webster Crowley; Nohra Chalouhi; David Hasan; Aaron S. Dumont; Pascal Jabbour; Kenneth C. Liu

Introduction. Idiopathic intracranial hypertension (IIH) may result in a chronic debilitating disease. Dural venous sinus stenosis with a physiologic venous pressure gradient has been identified as a potential etiology in a number of IIH patients. Intracranial venous stenting has emerged as a potential treatment alternative. Methods. A systematic review was carried out to identify studies employing venous stenting for IIH. Results. From 2002 to 2014, 17 studies comprising 185 patients who underwent 221 stenting procedures were reported. Mean prestent pressure gradient was 20.1 mmHg (95% CI 19.4–20.7 mmHg) with a mean poststent gradient of 4.4 mmHg (95% CI 3.5–5.2 mmHg). Complications occurred in 10 patients (5.4%; 95% CI 4.7–5.4%) but were major in only 3 (1.6%). At a mean clinical follow-up of 22 months, clinical improvement was noted in 130 of 166 patients with headaches (78.3%; 95% CI 75.8–80.8%), 84 of 89 patients with papilledema (94.4%; 95% CI 92.1–96.6%), and 64 of 74 patients with visual symptoms (86.5%; 95% CI 83.0–89.9%). In-stent stenosis was noted in six patients (3.4%; 95% CI 2.5–4.3%) and stent-adjacent stenosis occurred in 19 patients (11.4%; 95% CI 10.4–12.4), resulting in restenting in 10 patients. Conclusion. In IIH patients with venous sinus stenosis and a physiologic pressure gradient, venous stenting appears to be a safe and effective therapeutic option. Further studies are necessary to determine the long-term outcomes and the optimal management of medically refractory IIH.

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Dale Ding

Barrow Neurological Institute

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Ricky Medel

University of Virginia

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Ching-Jen Chen

University of Virginia Health System

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Thomas J. Buell

University of Virginia Health System

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Andrew F. Ducruet

Barrow Neurological Institute

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