Primary prevention of ischemic stroke: A statement for healthcare professionals from the Stroke Council of the American Heart Association.
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Biomedical subjects
Publications and source records attributed to L B Goldstein.
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BACKGROUND AND PURPOSE: The NIH Stroke Scale (NIHSS) and the Canadian Neurological Scale (CNS) have been reported to be useful for the retrospective assessment of initial stroke severity. However, unlike the CNS, the NIHSS requires detailed neurological assessments that may not be reflected in all patient records, potentially limiting its applicability. We assessed the reliability of the retrospective algorithms and the proportions of missing items for the NIHSS and CNS in stroke patients admitted to an academic medical center (AMC) and 2 community hospitals. METHODS: Randomly selected records of patients with ischemic stroke admitted to an AMC (n=20) and community hospitals with (CH1, n=19) and without (CH2, n=20) acute neurological consultative services were reviewed. NIHSS and CNS scores were assigned independently by 2 neurologists using published algorithms. Interrater reliability of the scores was determined with the intraclass correlation coefficient, and the numbers of missing items were tabulated. RESULTS: The intraclass correlation coefficient for NIHSS and CNS, respectively, were 0.93 (95% CI, 0.82 to 1.00) and 0.97 (95% CI, 0.90 to 1.00) for the AMC, 0.89 (95% CI, 0.75 to 1.00) and 0.88 (95%, 0.73 to 1.00) for the CH1, and 0.48 (95% CI, 0.26 to 0.70) and 0.78 (95% CI, 0.60 to 0.96) for the CH2. More NIHSS items were missing at the CH2 (62%) versus the AMC (27%) and the CH1 (23%, P:=0.0001). In comparison, 33%, 0%, and 8% of CNS items were missing from records from CH2, AMC, and CH1, respectively (P:=0.0001). CONCLUSIONS: The levels of interrater agreement were almost perfect for retrospectively assigned NIHSS and CNS scores for patients initially evaluated by a neurologist at both an AMC and a CH. Levels of agreement for the CNS were substantial at a CH2, but interrater agreement for the NIHSS was only moderate in this setting. The proportions of missing items are higher for the NIHSS than the CNS in each setting, particularly limiting its application in the hospital without acute neurological consultative services.
BACKGROUND AND PURPOSE: We sought to improve the reliability of the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification of stroke subtype for retrospective use in clinical, health services, and quality of care outcome studies. The TOAST investigators devised a series of 11 definitions to classify patients with ischemic stroke into 5 major etiologic/pathophysiological groupings. Interrater agreement was reported to be substantial in a series of patients who were independently assessed by pairs of physicians. However, the investigators cautioned that disagreements in subtype assignment remain despite the use of these explicit criteria and that trials should include measures to ensure the most uniform diagnosis possible. METHODS: In preparation for a study of outcomes and management practices for patients with ischemic stroke within Department of Veterans Affairs hospitals, 2 neurologists and 2 internists first retrospectively classified a series of 14 randomly selected stroke patients on the basis of the TOAST definitions to provide a baseline assessment of interrater agreement. A 2-phase process was then used to improve the reliability of subtype assignment. In the first phase, a computerized algorithm was developed to assign the TOAST diagnostic category. The reliability of the computerized algorithm was tested with a series of synthetic cases designed to provide data fitting each of the 11 definitions. In the second phase, critical disagreements in the data abstraction process were identified and remaining variability was reduced by the development of standardized procedures for retrieving relevant information from the medical record. RESULTS: The 4 physicians agreed in subtype diagnosis for only 2 of the 14 baseline cases (14%) using all 11 TOAST definitions and for 4 of the 14 cases (29%) when the classifications were collapsed into the 5 major etiologic/pathophysiological groupings (kappa=0.42; 95% CI, 0.32 to 0.53). There was 100% agreement between classifications generated by the computerized algorithm and the intended diagnostic groups for the 11 synthetic cases. The algorithm was then applied to the original 14 cases, and the diagnostic categorization was compared with each of the 4 physicians' baseline assignments. For the 5 collapsed subtypes, the algorithm-based and physician-assigned diagnoses disagreed for 29% to 50% of the cases, reflecting variation in the abstracted data and/or its interpretation. The use of an operations manual designed to guide data abstraction improved the reliability subtype assignment (kappa=0.54; 95% CI, 0.26 to 0.82). Critical disagreements in the abstracted data were identified, and the manual was revised accordingly. Reliability with the use of the 5 collapsed groupings then improved for both interrater (kappa=0.68; 95% CI, 0.44 to 0.91) and intrarater (kappa=0.74; 95% CI, 0.61 to 0.87) agreement. Examining each remaining disagreement revealed that half were due to ambiguities in the medical record and half were related to otherwise unexplained errors in data abstraction. CONCLUSIONS: Ischemic stroke subtype based on published TOAST classification criteria can be reliably assigned with the use of a computerized algorithm with data obtained through standardized medical record abstraction procedures. Some variability in stroke subtype classification will remain because of inconsistencies in the medical record and errors in data abstraction. This residual variability can be addressed by having 2 raters classify each case and then identifying and resolving the reason(s) for the disagreement.
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BACKGROUND: Patients with transient ischemic attack (TIA) or stroke frequently first contact their primary care physician rather than seeking care at a hospital emergency department. The purpose of the present study was to identify a group of patients seen by primary care physicians in an office setting for a first-ever TIA or stroke and characterize their evaluation and management. METHODS: Practice audit based on retrospective, structured medical record abstraction from 27 primary care medical practices in 2 geographically separate communities in the eastern United States. RESULTS: Ninety-five patients with a first-ever TIA and 81 with stroke were identified. Seventy-nine percent of those with TIA vs 88% with stroke were evaluated on the day their symptoms occurred (P =.12). Only 6% were admitted to a hospital for evaluation and treatment on the day of the index visit (2% TIA; 10% stroke; P =.03); only an additional 3% were admitted during the subsequent 30 days. Specialists were consulted for 45% of patients. A brain imaging study (computed tomography or magnetic resonance imaging) was ordered on the day of the index visit in 30% (23% TIA, 37% stroke; P =.04), regardless of whether the patient was referred to a specialist. Carotid ultrasound studies were obtained in 28% (40% TIA, 14% stroke; P<.001), electrocardiograms in 19% (18% TIA, 21% stroke; P =.60), and echocardiograms in 16% (19% TIA, 14% stroke; P =.34). Fewer than half of patients with a prior history of atrial fibrillation (n = 24) underwent anticoagulation when evaluated at the index visit. Thirty-two percent of patients (31% TIA, 33% stroke; P =.70) were not hospitalized and had no evaluations performed during the first month after presenting to a primary care physician with a first TIA or stroke. Of these patients, 59% had a change in antiplatelet therapy on the day of the index visit. CONCLUSIONS: Further primary care physician education regarding the importance of promptly and fully evaluating patients with TIA or stroke may be warranted, and barriers to implementation of established secondary stroke prevention strategies need to be carefully explored. Arch Intern Med. 2000;160:2941-2946
BACKGROUND: Most treatment of patients at risk for stroke is provided in the ambulatory setting. Although many studies have addressed the proportion of eligible patients with atrial fibrillation (AF) receiving warfarin sodium, few have addressed the quality of their anticoagulation management. OBJECTIVE: As a comprehensive assessment of quality, we analyzed the proportion of eligible patients receiving warfarin, the proportion of time their international normalized ratios (INRs) were within the target range, and, when an out-of-target range INR value occurred, the time until the next INR measurement was made. METHODS: Retrospective review of the medical records of 660 patients with AF managed by general internists and family practitioners in Rochester, NY, and the Research Triangle area of North Carolina. RESULTS: Only 34.7% of eligible patients with AF received warfarin. The INR values were out of the target range approximately half the time, and the response to these values was not always timely. For all the measures considered, both Rochester practices with access to an anticoagulation service had higher (albeit not ideal) quality of warfarin management than the remaining practices. CONCLUSIONS: We found significant deficiencies in the practice of warfarin management and suggestive evidence that anticoagulation services can partially ameliorate these deficiencies. More research is needed to describe the quality of anticoagulation management in typical practice and how this management can be improved.
Drugs modulating the levels of specific central neurotransmitters may influence both the rate and amount of functional recovery after focal brain injuries such as stroke. Because such drugs may be effective long after brain injury, the "therapeutic window" may be widened beyond the first few hour after stroke and an entirely new avenue for pharmacological intervention may be possible. The impact of drugs affecting norepinephrine and gamma-aminobutyric acid have been among the most extensively studied in the laboratory, and preliminary clinical data suggest similar effects in humans.
Recent studies have suggested that the risk of stroke may be increased in patients with several novel predisposing conditions. Although some controversy remains, the evidence supporting an association between moderately elevated levels of homocysteine and stroke is fairly strong. Studies are in progress to determine whether treatment with folate in combination with vitamins B(6) and B(12) will reduce the risk of stroke in patients with increased serum homocysteine. Evidence is also being gathered that suggests that patients with chronic inflammation, as well as those with chronic or acute infection, are at elevated stroke risk. The therapeutic implications of these latter associations have not yet been explored.
Motor recovery after unilateral sensorimotor cortex ablation or sham-injury was measured in apolipoprotein E knockout and wild-type mice by testing their abilities to traverse a narrow beam. All mice trained without difficulty. Sham-operated mice performed perfectly regardless of genotype throughout testing. There was no difference in motor scores between lesioned apolipoprotein E knockout and wild-type mice on a first trial 24h after injury (P>0.05). There was a significant overall effect of lesion on motor performance (two-way repeated measures analysis of variance F(1,42)=304, P<0.0001), a significant time effect (F(17,714)=58, P<0.0001) and a lesion by time interaction (F(17,714)=58, P<0.0001). However, there was no effect of apolipoprotein E genotype group on recovery rate (i.e. there was no lesion group by genotype group by time interaction, F(17,714)=0.33, P=1.00) and no effect of genotype on the final level of motor performance 12 days after the lesion (Kruskal-Wallis H=5.79, P=0.12). These data suggest that motor recovery after unilateral injury to the sensorimotor cortex does not vary with apolipoprotein E genotype.
BACKGROUND/PURPOSE: The aim of this study was to determine the statewide availability of facilities and programs for stroke prevention and treatment to identify underserved regions and target educational efforts. METHODS: A single-page survey was mailed to the directors of each inpatient medical facility in North Carolina. Data collected included the availability of selected diagnostic tests, programs, and services. Facilities were categorized as providing basic (emergency department, brain CT, treatment with rtPA, transthoracic echocardiography, carotid ultrasonography, cerebral angiography, carotid endarterectomy) or advanced (basic services plus brain MRI, MR angiography, transesophageal echocardiography, transcranial Doppler ultrasonography, interventional radiology) services. The availability of other programs and services, including having a neurologist on staff, organized anticoagulation clinics, inpatient rehabilitative services, diffusion-weighted MRI, community awareness and rapid stroke identification programs, stroke teams, stroke acute care units or an equivalent, and the use of stroke-care maps, were also determined. RESULTS: Complete responses were obtained from all of the state's 125 inpatient medical facilities. Overall, 97% of the state's population resided in counties with a hospital providing at least some stroke prevention or treatment procedures or services. Full basic services were provided by 23 facilities located in 19 of the state's 100 counties and were available to 52% of the state's population based on county of residence; advanced services were provided by 8 facilities located in 7 counties and were available to 26% of the state's population based on county of residence. Stroke-care maps were used in 83% of basic or advanced centers versus 23% of other hospitals (P<0.001), stroke teams were organized in 48% versus 12% (P=0.001), stroke units or equivalents were available in 61% versus 9% (P<0.001), rapid patient identification programs were in place in 57% versus 9% (P<0.001), and community awareness programs were in place in 57% versus 21% (P=0.005). CONCLUSIONS: Only 52% of the state's population reside in counties with hospitals providing full basic services; by expanding these services to only 6 additional facilities and thereby encompassing the state's 50 most populous counties, this proportion would be increased to 84%. Services that may improve outcomes and reduce costs (eg, stroke teams, stroke units, care maps) are not widely used, even in centers with full basic capabilities. Targeting educational efforts to these centers could improve the overall level of stroke care for the majority of the state's population. The study serves as a model that can be applied to other states and regions.
BACKGROUND: Hypercoagulable states are a recognized, albeit uncommon, etiology of ischemic stroke. It is unclear how often the results of specialized coagulation tests affect management. Using data compiled from a systematic review of available studies, we employed quantitative methodology to assess the diagnostic yield of coagulation tests for identification of coagulopathies in ischemic stroke patients. SUMMARY OF REVIEW: We performed a MEDLINE search to identify controlled studies published during 1966-1999 that reported the prevalence of deficiencies of protein C, protein S, antithrombin III, plasminogen, activated protein C resistance (APCR)/factor V Leiden mutation (FVL), anticardiolipin antibodies (ACL), or lupus anticoagulant (LA) in patients with ischemic stroke. The cumulative prevalence rates (pretest probabilities) and positive likelihood ratios for all studies and for those including only patients aged </=50 years were used to calculate posttest probabilities for each coagulopathy, reflecting diagnostic yield. The cumulative pretest probabilities of coagulation defects in ischemic stroke patients are as follows: LA, 3% (8% for those aged </=50 years); ACL, 17% (21% for those aged </=50 years); APCR/FVL, 7% (11% for those aged </=50 years); and prothrombin mutation, 4.5% (5.7% for those aged </=50 years). The posttest probabilities of ACL, LA, and APCR increased with increasing pretest probability, the specificity of the tests, and features of the patients' history and clinical presentation. CONCLUSIONS: The pretest probabilities of coagulation defects in ischemic stroke patients are low. The diagnostic yield of coagulation tests may be increased by using tests with the highest specificities and by targeting patients with clinical or historical features that increase pretest probability. Consideration of these data might lead to more rational ordering of tests and an associated cost savings.
Hypertension is a major risk factor for stroke and many patients with acute stroke have elevated blood pressures. The management of hypertension in the setting of acute ischaemic stroke remains a source of confusion and controversy. Lowering blood pressure in this setting may be hazardous because of impaired cerebral autoregulation. Treatment may be considered in patients who are otherwise candidates for thrombolytic therapy, patients who have severe hypertension or patients who have specific concomitant medical conditions including acute myocardial infarction, aortic dissection, hypertensive encephalopathy, or severe left ventricular failure. In choosing an agent for acute treatment, drugs that can produce a precipitous decline in blood pressure (e.g. sublingual calcium antagonists) should be avoided. Drugs with the capacity to dilate cerebral vessels should be used with caution as they have the potential to increase intracranial pressure. Long term management of hypertension in poststroke patients is often required. The potential for certain classes of drugs (e.g. alpha2-adrenergic receptor agonists and alpha1-adrenergic receptor antagonists) to impair the recovery process should be considered when choosing an antihypertensive for treatment of these patients.
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The practice of evidence-based medicine requires the interpretation and use of best evidence from a variety of potential sources as it may apply to an individual patient. There are three critical steps in the practice of evidence-based medicine. First, high quality data from randomized controlled trials, cohort studies, epidemiological research and other sources must be obtained. These results must then be effectively disseminated to health care providers. Finally, medical professionals must implement appropriate changes in their practices. However, available data suggest that there is a gap between physicians' existing stroke prevention and treatment practices and those supported by the results of clinical trials and other studies. New strategies such as the use of computerized decision support systems are being developed, but their impact on process of care, costs, and patient outcomes must be rigorously evaluated.
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