Scott E. Kasner

Guidelines for the Prevention of Stroke in Patients With Stroke or Transient Ischemic Attack A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association

The aim of this updated statement is to provide comprehensive and timely evidence-based recommendations on the prevention of ischemic stroke among survivors of ischemic stroke or transient ischemic attack. Evidence-based recommendations are included for the control of risk factors, interventional approaches for atherosclerotic disease, antithrombotic treatments for cardioembolism, and the use of antiplatelet agents for noncardioembolic stroke. Further recommendations are provided for the prevention of recurrent stroke in a variety of other specific circumstances, including arterial dissections; patent foramen ovale; hyperhomocysteinemia; hypercoagulable states; sickle cell disease; cerebral venous sinus thrombosis; stroke among women, particularly with regard to pregnancy and the use of postmenopausal hormones; the use of anticoagulation after cerebral hemorrhage; and special approaches to the implementation of guidelines and their use in high-risk populations.

Guidelines for the Prevention of Stroke in Patients With Stroke and Transient Ischemic Attack

The aim of this updated guideline is to provide comprehensive and timely evidence-based recommendations on the prevention of future stroke among survivors of ischemic stroke or transient ischemic attack. The guideline is addressed to all clinicians who manage secondary prevention for these patients. Evidence-based recommendations are provided for control of risk factors, intervention for vascular obstruction, antithrombotic therapy for cardioembolism, and antiplatelet therapy for noncardioembolic stroke. Recommendations are also provided for the prevention of recurrent stroke in a variety of specific circumstances, including aortic arch atherosclerosis, arterial dissection, patent foramen ovale, hyperhomocysteinemia, hypercoagulable states, antiphospholipid antibody syndrome, sickle cell disease, cerebral venous sinus thrombosis, and pregnancy. Special sections address use of antithrombotic and anticoagulation therapy after an intracranial hemorrhage and implementation of guidelines.

An Updated Definition of Stroke for the 21st Century A Statement for Healthcare Professionals From the American Heart Association/American Stroke Association

Despite the global impact and advances in understanding the pathophysiology of cerebrovascular diseases, the term “stroke” is not consistently defined in clinical practice, in clinical research, or in assessments of the public health. The classic definition is mainly clinical and does not account for advances in science and technology. The Stroke Council of the American Heart Association/American Stroke Association convened a writing group to develop an expert consensus document for an updated definition of stroke for the 21st century. Central nervous system infarction is defined as brain, spinal cord, or retinal cell death attributable to ischemia, based on neuropathological, neuroimaging, and/or clinical evidence of permanent injury. Central nervous system infarction occurs over a clinical spectrum: Ischemic stroke specifically refers to central nervous system infarction accompanied by overt symptoms, while silent infarction by definition causes no known symptoms. Stroke also broadly includes intracerebral hemorrhage and subarachnoid hemorrhage. The updated definition of stroke incorporates clinical and tissue criteria and can be incorporated into practice, research, and assessments of the public health.

Predictors of Ischemic Stroke in the Territory of a Symptomatic Intracranial Arterial Stenosis

Background— Antithrombotic therapy for intracranial arterial stenosis was recently evaluated in the Warfarin versus Aspirin for Symptomatic Intracranial Disease (WASID) trial. A prespecified aim of WASID was to identify patients at highest risk for stroke in the territory of the stenotic artery who would be the target group for a subsequent trial comparing intracranial stenting with medical therapy. Methods and Results— WASID was a randomized, double-blinded, multicenter trial involving 569 patients with transient ischemic attack or ischemic stroke due to 50% to 99% stenosis of a major intracranial artery. Median time from qualifying event to randomization was 17 days, and mean follow-up was 1.8 years. Multivariable Cox proportional hazards models were used to identify factors associated with subsequent ischemic stroke in the territory of the stenotic artery. Subsequent ischemic stroke occurred in 106 patients (19.0%); 77 (73%) of these strokes were in the territory of the stenotic artery. Risk of stroke in the territory of the stenotic artery was highest with severe stenosis ≥70% (hazard ratio 2.03; 95% confidence interval 1.29 to 3.22; P=0.0025) and in patients enrolled early (≤17 days) after the qualifying event (hazard ratio 1.69; 95% confidence interval 1.06 to 2.72; P=0.028). Women were also at increased risk, although this was of borderline significance (hazard ratio 1.59; 95% confidence interval 1.00 to 2.55; P=0.051). Location of stenosis, type of qualifying event, and prior use of antithrombotic medications were not associated with increased risk. Conclusions— Among patients with symptomatic intracranial stenosis, the risk of subsequent stroke in the territory of the stenotic artery is greatest with stenosis ≥70%, after recent symptoms, and in women.

A Pharmacogenetic versus a Clinical Algorithm for Warfarin Dosing

BACKGROUND The clinical utility of genotype-guided (pharmacogenetically based) dosing of warfarin has been tested only in small clinical trials or observational studies, with equivocal results. METHODS We randomly assigned 1015 patients to receive doses of warfarin during the first 5 days of therapy that were determined according to a dosing algorithm that included both clinical variables and genotype data or to one that included clinical variables only. All patients and clinicians were unaware of the dose of warfarin during the first 4 weeks of therapy. The primary outcome was the percentage of time that the international normalized ratio (INR) was in the therapeutic range from day 4 or 5 through day 28 of therapy. RESULTS At 4 weeks, the mean percentage of time in the therapeutic range was 45.2% in the genotype-guided group and 45.4% in the clinically guided group (adjusted mean difference, [genotype-guided group minus clinically guided group], -0.2; 95% confidence interval, -3.4 to 3.1; P=0.91). There also was no significant between-group difference among patients with a predicted dose difference between the two algorithms of 1 mg per day or more. There was, however, a significant interaction between dosing strategy and race (P=0.003). Among black patients, the mean percentage of time in the therapeutic range was less in the genotype-guided group than in the clinically guided group. The rates of the combined outcome of any INR of 4 or more, major bleeding, or thromboembolism did not differ significantly according to dosing strategy. CONCLUSIONS Genotype-guided dosing of warfarin did not improve anticoagulation control during the first 4 weeks of therapy. (Funded by the National Heart, Lung, and Blood Institute and others; COAG ClinicalTrials.gov number, NCT00839657.).

Magnetic resonance perfusion imaging in acute ischemic stroke using continuous arterial spin labeling.

BACKGROUND AND PURPOSE Continuous arterial spin-labeled perfusion MRI (CASL-PI) uses electromagnetically labeled arterial blood water as a diffusible tracer to noninvasively measure cerebral blood flow (CBF). We hypothesized that CASL-PI could detect perfusion deficits and perfusion/diffusion mismatches and predict outcome in acute ischemic stroke. METHODS We studied 15 patients with acute ischemic stroke within 24 hours of symptom onset. With the use of a 6-minute imaging protocol, CASL-PI was measured at 1.5 T in 8-mm contiguous supratentorial slices with a 3.75-mm in-plane resolution. Diffusion-weighted images were also obtained. Visual inspection for perfusion deficits, perfusion/diffusion mismatches, and effects of delayed arterial transit was performed. CBF in predetermined vascular territories was quantified by transformation into Talairach space. Regional CBF values were correlated with National Institutes of Health Stroke Scale (NIHSS) score on admission and Rankin Scale (RS) score at 30 days. RESULTS Interpretable CASL-PI images were obtained in all patients. Perfusion deficits were consistent with symptoms and/or diffusion-weighted imaging abnormalities. Eleven patients had hypoperfusion, 3 had normal perfusion, and 1 had relative hyperperfusion. Perfusion/diffusion mismatches were present in 8 patients. Delayed arterial transit effect was present in 7 patients; serial imaging in 2 of them showed that the delayed arterial transit area did not succumb to infarction. CBF in the affected hemisphere correlated with NIHSS and RS scores (P=0.037 and P=0.003, Spearman rank correlation). The interhemispheric percent difference in middle cerebral artery CBF correlated with NIHSS and RS scores (P=0.007 and P=0.0002, respectively). CONCLUSIONS CASL-PI provides rapid noninvasive multislice imaging in acute ischemic stroke. It depicts perfusion deficits and perfusion/diffusion mismatches and quantifies regional CBF. CASL-PI CBF asymmetries correlate with severity and outcome. Delayed arterial transit effects may indicate collateral flow.

Reliability and Validity of Estimating the NIH Stroke Scale Score from Medical Records

BACKGROUND AND PURPOSE The aim of our study was to determine whether the National Institutes of Health Stroke Scale (NIHSS) can be estimated retrospectively from medical records. The NIHSS is a quantitative measure of stroke-related neurological deficit with established reliability and validity for use in prospective clinical research. Recently, retrospective observational studies have estimated NIHSS scores from medical records for quantitative outcome analysis. The reliability and validity of estimation based on chart review has not been determined. METHODS Thirty-nine patients were selected because their NIHSS scores were formally measured at admission and discharge. Handwritten notes from medical records were abstracted and NIHSS scores were estimated by 6 raters who were blinded to the actual scores. Estimated scores were compared among raters and with the actual measured scores. RESULTS Interrater reliability was excellent, with an intraclass correlation coefficient of 0.82. Scores were well calibrated among the 6 raters. Estimated NIHSS scores closely approximated the actual scores, with a probability of 0.86 of correctly ranking a set of patients according to 5-point interval categories (as determined by the area under the receiver-operator characteristic curve). Patients with excellent outcomes (NIHSS score of </=5) could be identified with sensitivity of 0.72 and specificity of 0.89. There were no significant differences between these parameters at admission and discharge. CONCLUSIONS For the purposes of retrospective studies of acute stroke outcome, the NIHSS can be abstracted from medical records with a high degree of reliability and validity.

Practice parameter: recurrent stroke with patent foramen ovale and atrial septal aneurysm: report of the Quality Standards Subcommittee of the American Academy of Neurology.

Objectives: 1) To evaluate the risk of subsequent stroke or death in patients with a cryptogenic stroke and a patent foramen ovale (PFO), atrial septal aneurysm (ASA), or both. 2) To establish the optimal method of stroke prevention in this population of patients. Methods: MEDLINE, the Cochrane database of systematic reviews, key meeting abstracts from 1997 to 2002, and relevant reference lists were searched to select studies that prospectively collected outcome data in cryptogenic stroke patients with and without interatrial septal abnormalities. Studies were also selected that prospectively compared at least two treatment options. The quality of each study was graded (class I to IV) using a standard classification-of-evidence scheme for each question. Risk analyses were performed and data were pooled when appropriate. Results: The literature search generated 129 articles of which only four fulfilled the inclusion and exclusion criteria. Two studies were graded class I, one study was graded class II, and one study was graded class IV for prognosis. Pooled results of the two class I and one class II studies demonstrated no increased risk of subsequent stroke or death in patients with PFO compared to those without (RR = 0.95, 95% CI 0.62 to 1.44). One class I study found increased risk of recurrent stroke in patients with PFO and ASA (annual rate = 3.8% versus 1.05%, RR = 2.98, 95% CI 1.17 to 7.58) but not increased risk of a composite of stroke and death (annual rate = 3.8% versus 1.8%, RR = 2.10, 95% CI 0.86 to 5.06). Regarding therapy, one study was graded class II, one study class III, and two studies class IV. Among patients with cryptogenic stroke and PFO or ASA, there was no significant difference in stroke or death rate in warfarin-treated patients relative to aspirin-treated patients and the confidence intervals were unable to rule out a benefit of one drug over the other (annual rate = 4.7% versus 8.9%, RR = 0.53, 95% CI 0.18 to 1.58). Minor bleeding rates were higher in the cohort of patients who received warfarin (22.9/100 patient-years versus 8.66/100 patient-years, rate ratio = 2.64, p < 0.001). No studies compared medical therapy with surgical or endovascular closure. Conclusion: PFO is not associated with increased risk of subsequent stroke or death among medically treated patients with cryptogenic stroke. However, both PFO and ASA possibly increase the risk of subsequent stroke (but not death) in medically treated patients younger than 55 years. In patients with a cryptogenic stroke and an atrial septal abnormality the evidence is insufficient to determine if warfarin or aspirin is superior in preventing recurrent stroke or death, but minor bleeding is more frequent with warfarin. There is insufficient evidence to evaluate the efficacy of surgical or endovascular closure.Objectives1) To evaluate the risk of subsequent stroke or death in patients with a cryptogenic stroke and a patent foramen ovale (PFO), atrial septal aneurysm (ASA), or both. 2) To establish the optimal method of stroke prevention in this population of patients. MethodsMEDLINE, the Cochrane database of systematic reviews, key meeting abstracts from 1997 to 2002, and relevant reference lists were searched to select studies that prospectively collected outcome data in cryptogenic stroke patients with and without interatrial septal abnormalities. Studies were also selected that prospectively compared at least two treatment options. The quality of each study was graded (class I to IV) using a standard classification-of-evidence scheme for each question. Risk analyses were performed and data were pooled when appropriate. ResultsThe literature search generated 129 articles of which only four fulfilled the inclusion and exclusion criteria. Two studies were graded class I, one study was graded class II, and one study was graded class IV for prognosis. Pooled results of the two class I and one class II studies demonstrated no increased risk of subsequent stroke or death in patients with PFO compared to those without (RR = 0.95, 95% CI 0.62 to 1.44). One class I study found increased risk of recurrent stroke in patients with PFO and ASA (annual rate = 3.8% versus 1.05%, RR = 2.98, 95% CI 1.17 to 7.58) but not increased risk of a composite of stroke and death (annual rate = 3.8% versus 1.8%, RR = 2.10, 95% CI 0.86 to 5.06). Regarding therapy, one study was graded class II, one study class III, and two studies class IV. Among patients with cryptogenic stroke and PFO or ASA, there was no significant difference in stroke or death rate in warfarin-treated patients relative to aspirin-treated patients and the confidence intervals were unable to rule out a benefit of one drug over the other (annual rate = 4.7% versus 8.9%, RR = 0.53, 95% CI 0.18 to 1.58). Minor bleeding rates were higher in the cohort of patients who received warfarin (22.9/100 patient-years versus 8.66/100 patient-years, rate ratio = 2.64, p < 0.001). No studies compared medical therapy with surgical or endovascular closure. ConclusionPFO is not associated with increased risk of subsequent stroke or death among medically treated patients with cryptogenic stroke. However, both PFO and ASA possibly increase the risk of subsequent stroke (but not death) in medically treated patients younger than 55 years. In patients with a cryptogenic stroke and an atrial septal abnormality the evidence is insufficient to determine if warfarin or aspirin is superior in preventing recurrent stroke or death, but minor bleeding is more frequent with warfarin. There is insufficient evidence to evaluate the efficacy of surgical or endovascular closure.

Early Clinical and Radiological Predictors of Fatal Brain Swelling in Ischemic Stroke

BACKGROUND AND PURPOSE Early identification of acute stroke patients at risk of fatal brain swelling is necessary to facilitate implementation of aggressive therapies. Initial clinical, laboratory, and CT characteristics that may be used as selection criteria were analyzed to determine predictors of herniation and neurological death. METHODS Data from the placebo arm of the Lubeluzole-International-9 trial were reviewed to identify patients with fatal brain edema. Early clinical, laboratory, and radiographic parameters were evaluated in a case-control design. Initial CT scans were analyzed for early ischemic abnormalities by 2 blinded investigators. RESULTS Twenty-three patients died from brain swelling, with minimum baseline National Institutes of Health Stroke Scale (NIHSS) scores of 20 (n=12; mean, 23.2+/-1.8) with left and 15 (n=11; mean, 17.6+/-2.2) with right hemispheric infarctions (P=0. 0001). A sample of 112 subjects with comparably severe strokes, but who did not die from brain swelling, was selected from the remaining population according to the same NIHSS scores. Among clinical and laboratory characteristics, nausea/vomiting within 24 hours after onset (odds ratio [OR], 5.1; 95% CI, 1.7 to 15.3; P=0.003) and 12-hour systolic blood pressure >/=180 mm Hg (OR, 4.2; 95% CI, 1.4 to 12.9; P=0.01) were independently associated with fatal brain swelling. Among radiographic factors, only hypodensity of >50% of the middle cerebral artery territory on initial CT scan was an independent predictor (OR, 6.1; 95% CI, 2.3 to 16.6; P=0.0004). CONCLUSIONS Patients with baseline NIHSS score >/=20 with left or >/=15 with right hemispheric infarctions within 6 hours of symptom onset who also have nausea/vomiting or >50% middle cerebral artery territory hypodensity are at high risk for developing fatal brain swelling.

Early-onset stroke and vasculopathy associated with mutations in ADA2

BACKGROUND We observed a syndrome of intermittent fevers, early-onset lacunar strokes and other neurovascular manifestations, livedoid rash, hepatosplenomegaly, and systemic vasculopathy in three unrelated patients. We suspected a genetic cause because the disorder presented in early childhood. METHODS We performed whole-exome sequencing in the initial three patients and their unaffected parents and candidate-gene sequencing in three patients with a similar phenotype, as well as two young siblings with polyarteritis nodosa and one patient with small-vessel vasculitis. Enzyme assays, immunoblotting, immunohistochemical testing, flow cytometry, and cytokine profiling were performed on samples from the patients. To study protein function, we used morpholino-mediated knockdowns in zebrafish and short hairpin RNA knockdowns in U937 cells cultured with human dermal endothelial cells. RESULTS All nine patients carried recessively inherited mutations in CECR1 (cat eye syndrome chromosome region, candidate 1), encoding adenosine deaminase 2 (ADA2), that were predicted to be deleterious; these mutations were rare or absent in healthy controls. Six patients were compound heterozygous for eight CECR1 mutations, whereas the three patients with polyarteritis nodosa or small-vessel vasculitis were homozygous for the p.Gly47Arg mutation. Patients had a marked reduction in the levels of ADA2 and ADA2-specific enzyme activity in the blood. Skin, liver, and brain biopsies revealed vasculopathic changes characterized by compromised endothelial integrity, endothelial cellular activation, and inflammation. Knockdown of a zebrafish ADA2 homologue caused intracranial hemorrhages and neutropenia - phenotypes that were prevented by coinjection with nonmutated (but not with mutated) human CECR1. Monocytes from patients induced damage in cocultured endothelial-cell layers. CONCLUSIONS Loss-of-function mutations in CECR1 were associated with a spectrum of vascular and inflammatory phenotypes, ranging from early-onset recurrent stroke to systemic vasculopathy or vasculitis. (Funded by the National Institutes of Health Intramural Research Programs and others.).