Dawn Harris

Bio: Dawn Harris is an academic researcher from University College Dublin. The author has contributed to research in topics: Population & Stroke. The author has an hindex of 7, co-authored 7 publications receiving 744 citations.

Stroke Associated with Atrial Fibrillation – Incidence and Early Outcomes in the North Dublin Population Stroke Study

Abstract: Background: Prospective population-based studies are important to accurately determine the incidence and characteristics of stroke associated with atrial fibrillation (AF), while avoiding selection bias which may complicate hospital-based studies. Methods: We investigated AF-associated stroke within the North Dublin Population Stroke Study, a prospective cohort study of stroke/transient ischaemic attack in 294,592 individuals, according to recommended criteria for rigorous stroke epidemiological studies. Results: Of 568 stroke patients ascertained in the first year, 31.2% (177/568) were associated with AF (90.4%, i.e. 160/177 ischaemic infarcts). The crude incidence rate of all AF-associated stroke was 60/100,000 person-years (95% CI = 52–70). Prior stroke was almost twice as common in AF compared to non-AF groups (21.9 vs. 12.8%, p = 0.01). The frequency of AF progressively increased across ischaemic stroke patients stratified by increasing stroke severity (NIHSS 0–4, 29.7%; 5–9, 38.1%; 10–14, 43.8%; ≥15, 53.3%, p Discussion: AF-associated stroke occurred in one third of all patients and was associated with a distinct profile of recurrent, severe and disabling stroke. Targeted strategies to increase anticoagulation rates may provide a substantial benefit to prevent severe disabling stroke at a population level.

Stroke Subtype Classification to Mechanism-Specific and Undetermined Categories by TOAST, A-S-C-O, and Causative Classification System Direct Comparison in the North Dublin Population Stroke Study

Abstract: Background and Purpose— Reliable etiologic classification of ischemic stroke may enhance clinical trial design and identification of subtype-specific environmental and genetic risk factors. Although new classification systems (Causative Classification System [CCS] and ASCO [A for atherosclerosis, S for small vessel disease, C for cardiac source, O for other cause]) have been developed to improve subtype assignment, few comparative data exist from large studies. We hypothesized that both CCS and ASCO would reduce the proportion of patients classified as cause undetermined compared with the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) scheme in a large population-based stroke study. Methods— A single rater classified all first-ever ischemic strokes in the North Dublin Population Stroke Study, a population-based study of 294 529 North Dublin residents. Published algorithms for TOAST, CCS, and ASCO were applied. Results— In 381 first-ever ischemic stroke patients, CCS assigned fewer patients as cause ...

Population-Based Study of ABCD2 Score, Carotid Stenosis, and Atrial Fibrillation for Early Stroke Prediction After Transient Ischemic Attack. The North Dublin TIA Study

Abstract: Background and Purpose— Transient ischemic attack (TIA) etiologic data and the ABCD2 score may improve early stroke risk prediction, but studies are required in population-based cohorts. We investigated the external validity of the ABCD2 score, carotid stenosis, and atrial fibrillation for prediction of early recurrent stroke after TIA. Methods— Patients with TIA in the North Dublin city population (N=294 529) were ascertained by using overlapping hospital and community sources. The relations between individual ABCD2 items, carotid stenosis, atrial fibrillation, and early stroke were examined. Results— In confirmed TIA cases (n=443), carotid stenosis predicted 90-day stroke (hazard ratio=2.56; 95% CI, 1.27 to 5.15, P=0.003). Stroke risk rose with increasing grade of carotid stenosis, ranging from 5.4% (95% CI, 3.3% to 8.7%) with <50% stenosis to 17.2% (95% CI, 9.7% to 29.7%) with severe stenosis/occlusion (hazard ratio=3.3; 95% CI, 1.5 to 7.4, P=0.002). In confirmed TIA cases (n=443), the ABCD2 score perf...

Association Between Acute Statin Therapy, Survival, and Improved Functional Outcome After Ischemic Stroke The North Dublin Population Stroke Study

Abstract: Background and Purpose—Statins improve infarct volume and neurological outcome in animal stroke models. We investigated the relationship between statin therapy and ischemic stroke outcome in the North Dublin Population Stroke Study. Methods—A population-based prospective cohort study was performed using rigorous ascertainment methods. Prestroke and acute (≤72 hours) poststroke medications were recorded. Modified Rankin score and fatality were assessed at 7, 28, and 90 days and 1 year. Results—Of 448 ischemic stroke patients, statins were prescribed before stroke onset in 30.1% (134/445) and were begun acutely (≤72 hours) in an additional 42.5% (189/445). On logistic regression analysis, adjusting for age, prestroke disability (modified Rankin scale), NIHSS score, hypertension, and aspirin, new poststroke statin therapy was independently associated with improved early and late survival (compared with statin untreated patients: OR for death, 0.12; CI, 0.03–0.54 at 7 days; OR, 0.19; CI, 0.07–0.48 at 90 days;...

Diagnostic Usefulness of the ABCD2 Score to Distinguish Transient Ischemic Attack and Minor Ischemic Stroke From Noncerebrovascular Events The North Dublin TIA Study

Abstract: Background and Purpose— Transient ischemic attack (TIA) diagnosis is frequently difficult in clinical practice. Noncerebrovascular symptoms are often misclassified as TIA by nonspecialist physicians. Clinical prediction rules such as ABCD2 improve the identification of patients with TIA at high risk of early stroke. We hypothesized that the ABCD2 score may partly improve risk stratification due to improved discrimination of true TIA and minor ischemic stroke (MIS) from noncerebrovascular events. Methods— Consecutive patients with TIA were identified within a prospective population-based cohort study of stroke and TIA. The cohort was expanded by inclusion of patients with MIS and noncerebrovascular events referred to a daily TIA clinic serving the population. Diagnosis was assigned by a trained stroke physician independent of ABCD2 score. Results— Five hundred ninety-four patients were included (292 [49.2%] TIA, 45 [7.6%] MIS, and 257 [43.3%] noncerebrovascular). The mean ABCD2 score showed a graded increa...

Preventing Chronic Diseases: A Vital Investment

Abstract: Let's read! We will often find out this sentence everywhere. When still being a kid, mom used to order us to always read, so did the teacher. Some books are fully read in a week and we need the obligation to support reading. What about now? Do you still love reading? Is reading only for you who have obligation? Absolutely not! We here offer you a new book enPDFd preventing chronic diseases a vital investment to read.

Embolic strokes of undetermined source: the case for a new clinical construct

Abstract: Summary Cryptogenic (of unknown cause) ischaemic strokes are now thought to comprise about 25% of all ischaemic strokes. Advances in imaging techniques and improved understanding of stroke pathophysiology have prompted a reassessment of cryptogenic stroke. There is persuasive evidence that most cryptogenic strokes are thromboembolic. The thrombus is thought to originate from any of several well established potential embolic sources, including minor-risk or covert cardiac sources, veins via paradoxical embolism, and non-occlusive atherosclerotic plaques in the aortic arch, cervical, or cerebral arteries. Accordingly, we propose that embolic strokes of undetermined source are a therapeutically relevant entity, which are defined as a non-lacunar brain infarct without proximal arterial stenosis or cardioembolic sources, with a clear indication for anticoagulation. Because emboli consist mainly of thrombus, anticoagulants are likely to reduce recurrent brain ischaemia more effectively than are antiplatelet drugs. Randomised trials testing direct-acting oral anticoagulants for secondary prevention of embolic strokes of undetermined source are warranted.

Factors Influencing the Decline in Stroke Mortality A Statement From the American Heart Association/American Stroke Association

Abstract: Background and Purpose—Stroke mortality has been declining since the early 20th century. The reasons for this are not completely understood, although the decline is welcome. As a result of recent striking and more accelerated decreases in stroke mortality, stroke has fallen from the third to the fourth leading cause of death in the United States. This has prompted a detailed assessment of the factors associated with the change in stroke risk and mortality. This statement considers the evidence for factors that have contributed to the decline and how they can be used in the design of future interventions for this major public health burden. Methods—Writing group members were nominated by the committee chair and co-chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association Stroke Council’s Scientific Statements Oversight Committee and the American Heart Association Manuscript Oversight Committee. The writers used systematic literature reviews, references to published clinical and epidemiological studies, morbidity and mortality reports, clinical and public health guidelines, authoritative statements, personal files, and expert opinion to summarize evidence and to indicate gaps in current knowledge. All members of the writing group had the opportunity to comment on this document and approved the final version. The document underwent extensive American Heart Association internal peer review, Stroke Council leadership review, and Scientific Statements Oversight Committee review before consideration and approval by the American Heart Association Science Advisory and Coordinating Committee. Results—The decline in stroke mortality over the past decades represents a major improvement in population health and is observed for both sexes and for all racial/ethnic and age groups. In addition to the overall impact on fewer lives lost to stroke, the major decline in stroke mortality seen among people <65 years of age represents a reduction in years of potential life lost. The decline in mortality results from reduced incidence of stroke and lower case-fatality rates. These significant improvements in stroke outcomes are concurrent with cardiovascular risk factor control interventions. Although

Global epidemiology of atrial fibrillation

Abstract: Atrial fibrillation (AF) is a major public health burden worldwide, and its prevalence is set to increase owing to widespread population ageing, especially in rapidly developing countries such as Brazil, China, India, and Indonesia. Despite the availability of epidemiological data on the prevalence of AF in North America and Western Europe, corresponding data are limited in Africa, Asia, and South America. Moreover, other observations suggest that the prevalence of AF might be underestimated-not only in low-income and middle-income countries, but also in their high-income counterparts. Future studies are required to provide precise estimations of the global AF burden, identify important risk factors in various regions worldwide, and take into consideration regional and ethnic variations in AF. Furthermore, in response to the increasing prevalence of AF, additional resources will need to be allocated globally for prevention and treatment of AF and its associated complications. In this Review, we discuss the available data on the global prevalence, risk factors, management, financial costs, and clinical burden of AF, and highlight the current worldwide inadequacy of its treatment.

Atrial Fibrillation and Mechanisms of Stroke: Time for a New Model.

Abstract: Thirty-three million people have atrial fibrillation (AF), a disorder of heart rhythm.1 Over the past several decades, we have learned that this dysrhythmia originates in the interplay between genetic predisposition, ectopic electrical activity, and abnormal atrial tissue substrate and then feeds back to remodel and worsen tissue substrate and, thereby, propagates itself.2 Although the importance of AF partly derives from its strong association with ischemic stroke, there have not been as many advances in our understanding of the mechanisms of stroke in AF. Current views rest on a century old hypothesis that fibrillation of the atrium produces stasis of blood, which causes thrombus formation and embolism to the brain. When other abnormalities are acknowledged to play a role, the dysrhythmia is still considered the primary cause of thromboembolism.3 Although this formulation is intuitively appealing, recent work suggests that the pathogenesis of stroke in AF is more complicated and involves factors in addition to the dysrhythmia. AF and stroke have been associated in rigorous studies,4 indicating a true association rather than a spurious finding. Epidemiological logic suggests 3 explanations: (1) AF causes stroke, (2) stroke causes AF, and (3) AF is associated with other factors that cause stroke. To help judge whether one factor causes another or whether the 2 are simply correlated, the epidemiologist Bradford Hill proposed the following widely accepted criteria: (1) strength of association, (2) consistency, (3) specificity, (4) temporality, (5) biological gradient, (6) plausibility, (7) coherence, (8) accordance with experimental results, and (9) analogy.5 The relationship between AF and stroke fulfills several of these criteria. Patients with AF face a strongly elevated risk of stroke—about 3- to 5-fold higher after adjustment for risk factors.4 AF has been consistently associated with stroke in different cohorts.6 And a causal association is biologically …