Publications by authors named "Samuel Yip"

Background: We aimed to derive a clinical decision rule to identify patients with transient ischemic attack (TIA) or minor stroke most likely to benefit from echocardiography.

Methods: This multicentre prospective cohort study enrolled adults diagnosed with TIA/minor stroke in the emergency department who underwent echocardiograms within 90 days, from 13 Canadian academic emergency departments from October 2006 to May 2017. Our outcome was clinically significant echocardiogram findings.

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Objectives: Emergent vascular imaging identifies a subset of patients requiring immediate specialized care (i.e. carotid stenosis > 50%, dissection or free-floating thrombus).

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Background: Interhospital transfer for patients with stroke due to large vessel occlusion for endovascular thrombectomy (EVT) has been associated with treatment delays.

Methods: We analyzed data from Optimizing Patient Treatment in Major Ischemic Stroke With EVT, a quality improvement registry to support EVT implementation in Canada. We assessed for unadjusted differences in baseline characteristics, time metrics, and procedural outcomes between patients with large vessel occlusion transferred for EVT and those directly admitted to an EVT-capable center.

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Background: The optimal management of tandem carotid lesions during endovascular thrombectomy (EVT) remains uncertain. The safety and efficacy of acute carotid artery stenting (aCAS) are debated, including safety concerns such as procedural complications and symptomatic intracerebral hemorrhage (sICH). We aimed to assess aCAS safety among EVT-treated patients using a large Canadian registry.

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Background For patients with atrial fibrillation seen in the emergency department (ED) following a transient ischemic attack (TIA) or minor stroke, the impact of initiating oral anticoagulation immediately rather than deferring the decision to outpatient follow-up is unknown. Methods and Results We conducted a planned secondary data analysis of a prospective cohort of 11 507 adults in 13 Canadian EDs between 2006 and 2018. Patients were eligible if they were aged 18 years or older, with a final diagnosis of TIA or minor stroke with previously documented or newly diagnosed atrial fibrillation.

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Article Synopsis
  • The study validates that certain CT findings in patients with transient ischemic attack (TIA) are linked to an increased risk of subsequent strokes.
  • Among the 8670 patients enrolled, 4547 showed signs of ischemia on CT, with a subsequent stroke rate of 3.8% within 90 days.
  • Specific combinations of acute and chronic ischemia or microangiopathy significantly raised the risk of stroke, especially shortly after the initial event.
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The 2022 update of the , 7 edition, is a comprehensive summary of current evidence-based recommendations, appropriate for use by an interdisciplinary team of healthcare providers and system planners caring for persons with an acute stroke or transient ischemic attack. These recommendations are a timely opportunity to reassess current processes to ensure efficient access to acute stroke diagnostics, treatments, and management strategies, proven to reduce mortality and morbidity. The topics covered include prehospital care, emergency department care, intravenous thrombolysis and endovascular thrombectomy (EVT), prevention and management of inhospital complications, vascular risk factor reduction, early rehabilitation, and end-of-life care.

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Objective: Stroke presenting as dizziness is a diagnostic challenge in frontline settings, given the multitude of benign conditions that present similarly. The risk of stroke after episodic dizziness is unknown, leading to divergent guidance on optimal workup and management. Prior TIA risk scores have shown a history of dizziness is a negative predictor of subsequent stroke.

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Moyamoya (MM) disease is a chronic cerebrovascular disease that can lead to progressive stenosis of the terminal portions of the internal carotid arteries and their proximal branches. We sought to investigate and quantify retinal vascular changes in patients with MM vasculopathy (MMV) using optical coherence tomography angiography (OCTA) compared to healthy controls. Our findings reveal retinal microvascular changes in patients with MMV and highlights the potential of OCTA imaging for the detection of subclinical retinal pathology.

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Background: Transient ischemic attack (TIA) and non-disabling stroke are common emergency department (ED) presentations. Currently, there are no prospective multicenter studies determining predictors of neurologists confirming a diagnosis of cerebral ischemia in patients discharged with a diagnosis of TIA or stroke. The objectives were to (1) calculate the concordance between emergency physicians and neurologists for the outcome of diagnosing TIA or stroke, and (2) identify characteristics associated with neurologists diagnosing a stroke mimic.

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Objective: To measure the global impact of COVID-19 pandemic on volumes of IV thrombolysis (IVT), IVT transfers, and stroke hospitalizations over 4 months at the height of the pandemic (March 1 to June 30, 2020) compared with 2 control 4-month periods.

Methods: We conducted a cross-sectional, observational, retrospective study across 6 continents, 70 countries, and 457 stroke centers. Diagnoses were identified by their ICD-10 codes or classifications in stroke databases.

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Objective: To validate the previously derived Canadian TIA Score to stratify subsequent stroke risk in a new cohort of emergency department patients with transient ischaemic attack.

Design: Prospective cohort study.

Setting: 13 Canadian emergency departments over five years.

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Spontaneous intracerebral hemorrhage is a particularly devastating type of stroke with greater morbidity and mortality compared with ischemic stroke and can account for half or more of all deaths from stroke. The seventh update of the includes a new stand-alone module on intracerebral hemorrhage, with a focus on elements of care that are unique or affect persons disproportionately relative to ischemic stroke. Prior to this edition, intracerebral hemorrhage was included in the Acute Stroke Management module and was limited to its management during the first 12 h.

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Background: Rapid and accurate detection of stroke by paramedics or other emergency clinicians at the time of first contact is crucial for timely initiation of appropriate treatment. Several stroke recognition scales have been developed to support the initial triage. However, their accuracy remains uncertain and there is no agreement which of the scales perform better.

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Background And Purpose: Patients who have acute stroke symptoms present on awakening are ineligible for standard intravenous thrombolysis due to the unclear onset time of symptoms. Some of these wake-up stroke (WUS) patients may benefit from endovascular recanalization. This study aimed to evaluate clinical predictors of outcomes from endovascular recanalization in WUS patients.

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Background: Cerebral small vessel disease (CSVD) is a common cause of stroke, dementia, and functional decline. In recent years, neuroradiologic correlates of CSVD have been identified. These imaging findings, best characterized on magnetic resonance imaging (MRI), include some combination of white matter hyperintensities, lacunes, cerebral microbleeds, enlarged perivascular spaces, and cerebral atrophy.

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Background: Atrial fibrillation is a leading preventable cause of recurrent stroke for which early detection and treatment are critical. However, paroxysmal atrial fibrillation is often asymptomatic and likely to go undetected and untreated in the routine care of patients with ischemic stroke or transient ischemic attack (TIA).

Methods: We randomly assigned 572 patients 55 years of age or older, without known atrial fibrillation, who had had a cryptogenic ischemic stroke or TIA within the previous 6 months (cause undetermined after standard tests, including 24-hour electrocardiography [ECG]), to undergo additional noninvasive ambulatory ECG monitoring with either a 30-day event-triggered recorder (intervention group) or a conventional 24-hour monitor (control group).

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Introduction: Transient cortical visual impairment is a common aura of occipital lobe seizures. However, status amauroticus for hours has rarely been described as a manifestation of occipital lobe status epilepticus.

Purpose: To describe status amauroticus caused by focal status epilepticus of occipital lobe origin in two children with MRI findings consistent with posterior reversible encephalopathy syndrome.

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Krabbe disease is an autosomal recessive demyelinating lysosomal storage disorder caused by a deficiency of galactocerebrosidase. The adult-onset variant is very rare. Hematopoietic stem cell transplantation (HSCT) is reported to be successful in treating infants with Krabbe disease prior to the onset of symptoms, but there are no reported cases of its use for adult-onset disease.

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Stroke is one of the leading causes of disability and death. Ischemic stroke is a syndrome with heterogeneous mechanisms and multiple etiologies, rather than a singularly defined disease. Approximately one third of ischemic strokes are preceded by another cerebrovascular ischemic event.

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In women ages 15-45 years, an additional set of risk factors are important in the pathogenesis of ischemic stroke. Some of these pertain strictly to women, and relate to exogenous hormones and pregnancy. Various other conditions are more common in women, which include migraine with aura, selected vascular disorders and autoimmune conditions.

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