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L Nelson Hopkins

Publications and source records attributed to L Nelson Hopkins.

At least 37 records · Page 2Linked to original sources
PubMed2005

Stent placement for the treatment of nonsaccular aneurysms of the vertebrobasilar system.

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.

Basilar Artery↗
PubMed2005

Toward clinical equipoise: the current case for carotid angioplasty and stent placement.

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.

Angioplasty↗
PubMed2005

Endovascular management of carotid artery disease after radiation therapy and radical neck dissection.

OBJECT: More patients with head and neck cancers who undergo radical neck dissection and adjuvant radiation are experiencing prolonged survival times. Because of their improved survival, patients are living long enough to suffer the delayed effects of radiation therapy. Radiation-induced carotid artery (CA) stenosis in patients with or without radical neck dissection often requires extensive exposure and vessel reconstruction. The aim of this study was to evaluate the efficacy of endovascular treatment as an alternative therapy for radiation-induced CA stenosis. METHODS: Coinciding with the improved longevity of these patients, CA angioplasty and stent placement has become a definitive treatment strategy for this particularly challenging group of individuals. Long lesions are easily addressed with multiple telescoped stents. The tendency toward early restenosis can now be addressed with cutting balloon angioplasty. A review of the authors' institutional database yielded five patients (four men and one woman) with a history of radiation treatment ipsilateral to their CA stenosis. Three of five patients were symptomatic, and the interval between radiation therapy and endovascular treatment ranged from 1 to 47 years (mean 16.6 years). Four of the five patients were treated using distal embolic protection devices, and all patients underwent balloon dilation after stent placement. CONCLUSIONS: As advancements are made in the technology and techniques for CA angioplasty and stent placement, the safety and durability of treatments in patients with radiation-induced atherosclerotic disease will improve.

Aged↗
PubMed2005

Outcomes in acute ischemic stroke patients without angiographically documented arterial occlusion.

BACKGROUND AND PURPOSE: Patients with acute ischemic stroke who undergo emergent cerebral angiography for consideration of intra-arterial treatment and do not have an angiographically demonstrable occlusion pose a management dilemma. The authors reviewed their experience to determine the clinical out comes of patients with ischemic stroke evaluated within 6 hours of symptom onset in whom negative angiograms were obtained. METHODS: A prospective registry was maintained for all patients (N = 56) who were considered for intra-arterial thrombolysis. Patients without angiographic arterial occlusion were not treated with thrombolytics, and data pertaining to clinical characteristics and neuroimaging findings was collected. Follow-up data were acquired through clinic visits or telephone interviews at 5.5 +/- 5.0 months (mean +/- SD), range 1 to 15 months, after onset of stroke. RESULTS: Of the 56 patients, no arterial occlusion was observed in 17 (30%) patients (mean age 65.8 +/- 13.0 years; 7 were men). The mean (+/- SD) baseline National Institute of Health stroke scale score was 10.2 +/- 7.1. Symptoms were referable to the anterior or posterior circulation in 76% and 18% of the patients, respectively; they could not be localized to either circulation in 6%. Follow-up neuroimaging studies demonstrated cerebral infarction in 12 of 14 patients. Eleven of the 17 had a favorable long-term recovery as assessed by the modified Rankin Scale (score 0 or 1). Five other patients had modified Rankin Scale scores of 3 (n = 1), 4 (n = 2), or 5 (n = 2). One patient died during the follow-up period. With regard to location of ischemic deficits, the highest rate of death or dependency was observed in patients with pontine infarction (three of four patients). CONCLUSION: Although the outcome following ischemic stroke in patients without angiographically documented occlusion appears to be better than that reported for patients with angiographically documented occlusion, death or disability is observed in at least one third of the patients. There fore, acute ischemic stroke in the absence of angiographic occlusion is not entirely a "benign" entity and can be particularly devastating when the brainstem is involved.

Aged↗
PubMed2005

Clinical and angiographic results of dilatation procedures for symptomatic intracranial atherosclerotic disease.

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.

Angiography, Digital Subtraction↗
PubMed2005

Mathematical model of the rupture mechanism of intracranial saccular aneurysms through daughter aneurysm formation and growth.

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.

Aneurysm, Ruptured↗
PubMed2005

Recent advances in endoluminal revascularization for intracranial atherosclerotic disease.

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.

Endarterectomy↗
PubMed2005

Computed tomographic perfusion in the management of aneurysmal subarachnoid hemorrhage: new application of an existent technique.

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.

Adult↗
PubMed2005

Trends in hospitalization and mortality for subarachnoid hemorrhage and unruptured aneurysms in the United States.

OBJECTIVE: During the past decade, endovascular obliteration of intracranial aneurysms and new treatments for vasospasm and cerebral ischemia have been introduced. To analyze the effectiveness of these new strategies, we evaluated changes in morbidity and mortality rates in patients at least 18 years of age who were hospitalized for ruptured and unruptured intracranial aneurysms during the past 16 years. METHODS: National estimates of hospitalization for subarachnoid hemorrhage (SAH) and unruptured intracranial aneurysms and associated in-hospital outcomes and mortality were obtained from National Hospital Discharge Survey data. All the variables pertaining to hospitalization were compared for three distinct time periods: 1986-1990, 1991-1995, and 1996-2001. RESULTS: There were 94,692, 104,746, and 133,269 admissions for SAH during the periods 1986-1990, 1991-1995, and 1996-2001, respectively. Mortality rates for hospitalizations related to SAH demonstrated no significant change in mortality during the periods 1986-1990, 1991-1995, and 1996-2001 (27.6%, 24.6%, and 26.3%, respectively. Procedures performed for SAH from 1996 to 2001 included surgical clipping (28%), endovascular/wrapping (2%), and no procedure (70%). The number of admissions for unruptured intracranial aneurysms was 23,481 from 1986 to 1990, 28,017 from 1991 to 1995, and 51,904 from 1996 to 2001. There was an overall trend (P = 0.07) toward reduced in-hospital mortality during the three periods: 5.9%, 6.3%, and 1.4% for 1986-1990, 1991-1995, and 1996-2001, respectively. CONCLUSION: The mortality rate for unruptured intracranial aneurysms demonstrates a significant trend of reduction during the past 16 years. The mortality rate for SAH demonstrates limited change during the same period; it is presumed that this is attributable to the multitude of factors that influence outcome.

Adolescent↗
PubMed2005

Submaximal angioplasty and staged stenting for severe posterior circulation intracranial stenosis: a technique in evolution.

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.

Angioplasty, Balloon↗
PubMed2005

CT perfusion cerebral blood flow imaging in neurological critical care.

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.

Aged↗
PubMed2005

The safety and feasibility of continuous intravenous magnesium sulfate for prevention of cerebral vasospasm in aneurysmal subarachnoid hemorrhage.

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.

Adult↗