Publications by authors named "David C Anderson"
A design for an incident-beam collimator for the Paris-Edinburgh pressure cell is described here. This design can be fabricated from reaction-bonded BC but also through fast turnaround, inexpensive 3D-printing. 3D-printing thereby also offers the opportunity of composite collimators whereby the tip closest to the sample can exhibit even better neutronic characteristics.
View Article and Find Full Text PDFObjective: We conducted an online survey to gauge the acceptance of sending acute stroke patients with suspected large vessel occlusion (LVO) directly to an endovascular-capable hospital (ECH) even if that means bypassing a closer alteplase-capable hospital (ACH) without endovascular capability.
Methods: The survey was composed of two cases of acute stroke, one with cortical symptoms suggestive of LVO and the other without. In each case, responders were asked to choose between triaging to a closer ACH or an ECH that is further away and to provide an opinion regarding the maximum extra travel time they would tolerate if they chose the ECH.
Objective: To characterize cerebral microbleeds (CMBs) in lacunar stroke patients in the Secondary Prevention of Small Subcortical Strokes (SPS3) trial and to assess their relationship with recurrent stroke and death, and response to assigned treatment.
Methods: SPS3 is a randomized, clinical trial conducted between 2003 and 2011. Patients with recent magnetic resonance imaging (MRI)-documented lacunar infarcts were randomly assigned in a factorial design to target levels of systolic blood pressure (130-149mmHg vs <130mmHg; open label) and to antiplatelet treatment (aspirin/clopidogrel vs aspirin/placebo; double-blinded).
Background: Pontine infarcts are common and often attributed to small vessel disease ("small deep infarcts") or basilar branch atherosclerosis ("wedge shaped"). A well-described morphological differentiation using magnetic resonance images has not been reported. Furthermore, whether risk factors and outcomes differ by morphology, or whether infarct morphology should guide secondary prevention strategy, is not well characterized.
View Article and Find Full Text PDFBackground: Preceding low-frequency repetitive transcranial magnetic stimulation (rTMS) with a bout of high-frequency rTMS called priming potentiates the after-effects of the former in healthy adults. The utility of primed rTMS in stroke remains under-explored despite its theoretical benefits in enhancing cortical excitability and motor function.
Objective: To ascertain the efficacy of priming in chronic stroke by comparing changes in cortical excitability and paretic hand function following three types of primed low-frequency rTMS treatments.
Background: The clinical implications of vertebrobasilar ectasia (VBE) in patients with cerebral small-artery disease are not well defined. We investigated whether VBE is associated with recurrent stroke, major hemorrhage, and death in a large cohort of patients with recent lacunar stroke.
Methods: Maximum diameters of the vertebral and basilar arteries were measured by magnetic resonance angiography and computed tomographic angiography in 2621 participants in the Secondary Prevention of Small Subcortical Strokes trial.
Background: The primary outcome results for the SPS3 trial suggested that a lower systolic target blood pressure (<130 mm Hg) might be beneficial for reducing the risk of recurrent stroke compared with a higher target (130-149 mm Hg), but that the addition of clopidogrel to aspirin was not beneficial compared with aspirin plus placebo. In this prespecified secondary outcome analysis of the SPS3 trial, we aimed to assess whether blood pressure reduction and dual antiplatelet treatment affect changes in cognitive function over time in patients with cerebral small vessel disease.
Methods: In the SPS3 trial, patients with recent (within 6 months) symptomatic lacunar infarcts from 81 centres in North America, Latin America, and Spain were randomly assigned, in a two-by-two factorial design, to target levels of systolic blood pressure (1:1; 130-149 mm Hg vs <130 mm Hg; open-label) and to a once-daily antiplatelet treatment (1:1; aspirin 325 mg plus clopidogrel 75 mg vs aspirin 325 mg plus placebo; double-blind).
Background And Purpose: Infarct size and location are thought to correlate with different mechanisms of lacunar infarcts. We examined the relationship between the size and shape of lacunar infarcts and vascular risk factors and outcomes.
Methods: We studied 1679 participants in the Secondary Prevention of Small Subcortical Stroke trial with a lacunar infarct visualized on diffusion-weighted imaging.
Background And Purpose: The Secondary Prevention of Small Subcortical Stroke trial (SPS3) recruited participants meeting clinical and radiological criteria for symptomatic lacunes. Individuals randomized to dual antiplatelet therapy with clopidogrel and aspirin had an unanticipated increase in all-cause mortality compared with those assigned to aspirin. We investigated the factors associated with mortality in this well-characterized population.
View Article and Find Full Text PDFBackground And Purpose: We report on trends in poststroke survival, both in the early period after stroke and over the long term. We examine these trends by stroke subtype.
Methods: The Minnesota Stroke Survey is a study of all hospitalized patients with acute stroke aged 30 to 74 years in the Minneapolis-St Paul metropolis.
Purpose: This study analyzed the characteristics of responders vs. nonresponders in people with stroke receiving a novel form of repetitive transcranial magnetic stimulation (rTMS) to improve hand function.
Methods: Twelve people with stroke received five treatments of 6-Hz primed low-frequency rTMS to the contralesional primary motor area.
Objective: To assess whether adding clopidogrel to acetylsalicylic acid (ASA) has a long-term protective vascular effect in patients with lacunar stroke while taking ASA.
Methods: Post hoc analysis of 838 patients with ASA failure and recent lacunar stroke from the Secondary Prevention of Small Subcortical Strokes Trial (SPS3) cohort randomly allocated to aspirin (325 mg/day) and clopidogrel (75 mg/day) or placebo. Primary efficacy outcome was stroke recurrence (ischemic and intracranial hemorrhage) and main safety outcome was major extracranial hemorrhage.
Background And Purpose: In Atherothrombosis Intervention in Metabolic Syndrome with low HDL/High Triglycerides: Impact on Global Health Outcomes (AIM-HIGH) trial, addition of extended-release niacin (ERN) to simvastatin in participants with established cardiovascular disease, low high-density lipoprotein cholesterol, and high triglycerides had no incremental benefit, despite increases in high-density lipoprotein cholesterol. Preliminary analysis based on incomplete end point adjudication suggested increased ischemic stroke risk among participants randomized to ERN.
Methods: This final analysis was conducted after complete AIM-HIGH event ascertainment to further explore potential relationship between niacin therapy and ischemic stroke risk.
Background: Among participants in the Secondary Prevention of Small Subcortical Strokes randomized trial, we sought to identify patients with high versus low rates of recurrent ischemic stroke and to assess effects of aggressive blood pressure control and dual antiplatelet therapy according to risk status.
Methods: Multivariable analyses of 3020 participants with recent magnetic resonance imaging-defined lacunar strokes followed for a mean of 3.7 years with 243 recurrent ischemic strokes.
Objective: To assess evidence regarding periprocedural management of antithrombotic drugs in patients with ischemic cerebrovascular disease. The complete guideline on which this summary is based is available as an online data supplement to this article.
Methods: Systematic literature review with practice recommendations.
Background: It remains controversial whether dual antiplatelet therapy reduces stroke more than aspirin alone.
Aim: We aimed to assess the effects of adding clopidogrel to aspirin on the occurrence of stroke and major haemorrhage in patients with vascular disease.
Methods: Meta-analysis of published randomized trials comparing the combination of clopidogrel and aspirin vs.
This review examines the role of platelets in ischemic stroke, platelet activation mechanisms, aspirin's rise as an antithrombotic agent, clopidogrel's appearance on the stage, a possible role for combination therapy, antiplatelet resistance, practical considerations, and future directions. Reviewed in this chapter are issues central to optimal antiplatelet therapy: efficacy, safety, resistance, and biochemical/laboratory testing. Current guidelines do not recommend combination aspirin and clopidogrel use, however recent research indicates dual antiplatelet therapy with combined aspirin and clopidogrel may have specific roles in secondary prevention of ischemic stroke.
View Article and Find Full Text PDFBackground: The American Heart Association and the American Stroke Association recommend intravenous (IV) thrombolysis up to 4.5 h from acute ischemic stroke symptom onset based on its proven benefit in improving patient outcomes. We analyzed data from the Minnesota Stroke Registry to assess the rates of IV thrombolytic utilization and the process of care in this expanded window.
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