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L M Brass

Publications and source records attributed to L M Brass.

At least 37 records · Page 2Linked to original sources
PubMed2000

The stroke prognosis instrument II (SPI-II) : A clinical prediction instrument for patients with transient ischemia and nondisabling ischemic stroke.

BACKGROUND AND PURPOSE: In 1991 we developed the Stroke Prognosis Instrument (SPI-I) to stratify patients with transient ischemic attack or ischemic stroke by prognosis for stroke or death in 2 years. In this article we validate and improve SPI-I (creating SPI-II). METHODS: To validate SPI-I, we applied it to 4 test cohorts and calculated pooled outcome rates. To create SPI-II, we incorporated new predictive variables identified in 1 of the test cohorts and validated it in the other 3 cohorts. RESULTS: For SPI-I, pooled rates (all 4 test cohorts) of stroke or death within 2 years in risk groups I, II, and III were 9%, 17%, and 24%, respectively (P<0.01, log-rank test). SPI-II was created by adding congestive heart failure and prior stroke to SPI-I. Each patient's risk group was determined by the total score for 7 factors: congestive heart failure (3 points); diabetes (3 points); prior stroke (3 points); age >70 years (2 points); stroke for the index event (not transient ischemic attack) (2 points); hypertension (1 point); and coronary artery disease (1 point). Risk groups I, II, and III comprised patients with 0 to 3, 4 to 7, and 8 to 15 points, respectively. For SPI-I, pooled rates (3 cohorts excluding the SPI-II development cohort) of stroke or death within 2 years in risk groups I, II, and III were 9%, 17%, and 23%, respectively. For SPI-II, pooled rates were 10%, 19%, and 31%, respectively. In receiver operator characteristic analysis, the area under the curve was 0.59 (95% CI, 0.57 to 0.60) for SPI-I and 0.63 (95% CI, 0.62 to 0.65) for SPI-II, confirming the better performance of the latter. CONCLUSIONS: Compared with SPI-I, SPI-II achieves greater discrimination in outcome rates among risk groups. SPI-II is ready for use in research design and may have a role in patient counseling.

Aged↗
PubMed2000

Intracranial hemorrhage associated with thrombolytic therapy for elderly patients with acute myocardial infarction: results from the Cooperative Cardiovascular Project.

BACKGROUND AND PURPOSE: Intracranial hemorrhage is a serious complication of thrombolytic therapy for acute myocardial infarction, especially among the elderly, but little information exists on estimating risk. Better estimation of risk in individual patients may allow for withholding or using alternate therapies among those at highest risk. METHODS: To quantify the risk and identify predictors of intracranial hemorrhage associated with thrombolytic therapy, we performed a retrospective cohort study using data from medical charts. The study involved nearly all acute-care hospitals in the United States. All Medicare patients discharged with a principal diagnosis of acute myocardial infarction during a 9-month period in 1994 to 1995 were included. The main outcome measure was intracranial hemorrhage among those treated with thrombolytic therapy. RESULTS: The rate of intracranial hemorrhage was 1.43% (455 of 31 732). In a logistic model, age > or =75 years, female, black race, prior stroke, blood pressure > or =160 mm Hg, tissue plasminogen activator (versus other thrombolytic agent), excessive anticoagulation (international normalized ratio > or =4 or prothrombin time > or =24), and below median weight (< or =65 kg for women; < or =80 kg for men) were independent predictors. A risk stratification scale was developed on the basis of these factors: with none or 1 of the factors (n=6651), the rate of intracranial hemorrhage was 0.69%; with 2 factors (n=10 509), 1.02%; with 3 factors (n=9074), 1.63%; with 4 factors (n=4298), 2.49%; and with > or =5 factors (n=1071), 4. 11% (Mantel-Haenszel; P<0.001). CONCLUSIONS: The rate of intracranial hemorrhage in older patients after treatment with thrombolytic therapy exceeds 1%. Readily available factors can identify elderly patients with acute myocardial infarction at high and low risk for intracranial hemorrhage associated with thrombolytic therapy.

Age Factors↗
PubMed1999

Stratified randomization for clinical trials.

Trialists argue about the usefulness of stratified randomization. For investigators designing trials and readers who use them, the argument has created uncertainty regarding the importance of stratification. In this paper, we review stratified randomization to summarize its purpose, indications, accomplishments, and alternatives. In order to identify research papers, we performed a Medline search for 1966-1997. The search yielded 33 articles that included original research on stratification or included stratification as the major focus. Additional resources included textbooks. Stratified randomization prevents imbalance between treatment groups for known factors that influence prognosis or treatment responsiveness. As a result, stratification may prevent type I error and improve power for small trials (<400 patients), but only when the stratification factors have a large effect on prognosis. Stratification has an important effect on sample size for active control equivalence trials, but not for superiority trials. Theoretical benefits include facilitation of subgroup analysis and interim analysis. The maximum desirable number of strata is unknown, but experts argue for keeping it small. Stratified randomization is important only for small trials in which treatment outcome may be affected by known clinical factors that have a large effect on prognosis, large trials when interim analyses are planned with small numbers of patients, and trials designed to show the equivalence of two therapies. Once the decision to stratify is made, investigators need to chose factors carefully and account for them in the analysis.

Bias↗
PubMed1998

Warfarin use following ischemic stroke among Medicare patients with atrial fibrillation.

BACKGROUND: Elderly patients with ischemic stroke and atrial fibrillation are at especially increased risk for recurrent stroke. Warfarin sodium is highly effective in reducing this risk. OBJECTIVE: To determine the use of warfarin among a population sample of elderly patients with atrial fibrillation hospitalized for ischemic stroke. METHODS: The Connecticut Peer Review Organization conducted a chart review of Medicare patients, aged 65 years or older, hospitalized in 1994 with a diagnosis of atrial fibrillation. Patients with a principal diagnosis of acute myocardial infarction or another indication for anticoagulation were excluded. RESULTS: Among 635 patients (402 women; 585 white; 218 > or =85 years old; 147 with a new diagnosis of atrial fibrillation), 334 had stroke as a principal diagnosis. Among those discharged alive after a stroke, only 147 (53%) of 278 were prescribed warfarin at discharge. Furthermore, among 130 (47%) of 278 patients not prescribed warfarin at discharge, 81 (62%) of 130 were also not prescribed aspirin. Increased potential benefit (additional vascular risk factors) was not associated with a higher rate of warfarin use. Low risk for anticoagulation (lack of risk factors for bleeding) was associated with a slightly higher rate of warfarin use. Among those with an increased risk of stroke and a low risk for bleeding (ideal candidates), 124 (62%) of 278 were discharged on a regimen of warfarin. CONCLUSION: Anticoagulation of elderly stroke patients with atrial fibrillation, even among ideal candidates, is underused. The increased use of warfarin among these patients represents an excellent opportunity for reducing the risk of recurrent stroke in this high-risk population.

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PubMed1998

Development of a test battery to identify older drivers at risk for self-reported adverse driving events.

OBJECTIVES: The purposes of this study were (1) to develop a battery of tests that assessed a wide range of functional abilities relevant to driving yet could be performed in a clinician's office and (2) to determine which of these tests were most closely associated with self-reported adverse driving events. DESIGN: A cohort study. SETTING: An urban community. PARTICIPANTS: Participants were drawn from the Project Safety cohort, a probability sample of noninstitutionalized older persons in New Haven, Connecticut, initiated in 1989. The current study included surviving, active drivers in the cohort (N=125). MEASURES: The test battery assessed visual, cognitive, and physical abilities potentially relevant to driving, and was administered in participants' homes by trained interviewers between October 1994 and July 1995. Outcome measures included the self-report of a crash, moving violation, or being stopped by police in any Project Safety interview since the inception of the cohort. Analyses compared performance on the elements of the test battery with participants' histories of adverse driving events. RESULTS: Of the 125 drivers, 50 (40%) had reported an adverse event in a mean period of 5.76 (+/-.25) years before the current interview. The elements of the test battery independently associated with a history of events, adjusting for driving frequency, included near visual acuity worse than 20/40 (adjusted odds ratio 11.90), limited neck rotation (OR 6.10), and poor performance on a test of visual attention, the number cancellation task (OR 3.00). The resulting regression equation yielded a sensitivity of 80%, a specificity of 55%, and an area under the curve of .75 by receiver operating characteristic analysis. CONCLUSION: These findings suggest it may be possible to identify individuals potentially at risk for self-reported adverse driving events using simple tests of functional ability. If validated, such an approach could be used to identify individuals who need a more detailed assessment of functional abilities to determine the severity and etiology of impairments, and their effect on driving performance, as well as possible interventions to correct or compensate for the impairments.

Accidents, Traffic↗
PubMed1998

Risk factors for stroke and type of stroke in persons with isolated systolic hypertension. Systolic Hypertension in the Elderly Program Cooperative Research Group.

BACKGROUND AND PURPOSE: We sought to determine risk factors for stroke and stroke type in persons with isolated systolic hypertension (ISH). METHODS: We performed proportional hazards analyses of data from the Systolic Hypertension in the Elderly Program, a double-blind, randomized, placebo-controlled trial of 4736 persons aged > or =60 years with ISH (systolic blood pressure, 160 to 219 mm Hg; diastolic blood pressure, <90 mm Hg). One treatment group received chlorthalidone (12.5 to 25 mg/d) with step-up to atenolol (25.0 to 50.0 mg/d) or reserpine (0.05 to 0.10 mg/d), if needed. The other treatment group received matching placebo. The main outcome measures were stroke, stroke or transient ischemic attack [TIA], and stroke types: ischemic (including lacunar, atherosclerotic, and embolic) and hemorrhagic. RESULTS: During an average follow-up of 4.5 years, 384 strokes or TIAs and 262 strokes (including 217 ischemic, 66 lacunar, 26 atherosclerotic, and 25 embolic strokes) were documented. In multivariate analyses, placebo treatment, older age, smoking, history of diabetes, higher systolic blood pressure, lower HDL cholesterol, and ECG abnormality were significantly associated (P<0.05) with increased incidence of stroke or TIA, stroke, or ischemic stroke. Greater lacunar stroke risk was significantly related to placebo treatment, older age, history of diabetes (relative risk [RR] = 3.03; 95% confidence interval [CI], 1.70 to 5.40), and smoking (RR = 3.04; 95% CI, 1.73 to 5.37). Greater atherosclerotic and embolic stroke risk were significantly related to presence of carotid bruit (RR = 5.75; 95% CI, 2.50 to 13.24) and older age (RR = 1.65 per 5 years; 95% CI, 1.25 to 2.18), respectively. CONCLUSIONS: In older persons with ISH, history of diabetes and smoking are important risk factors for lacunar stroke, whereas carotid bruit and age are important risk factors for atherosclerotic and embolic stroke, respectively.

Aged↗
PubMed1997

Warfarin use among patients with atrial fibrillation.

BACKGROUND AND PURPOSE: Warfarin reduces the rate of stroke among patients with atrial fibrillation. We sought to determine warfarin use within a population sample of elderly patients with atrial fibrillation. METHODS: The Connecticut Peer Review Organization conducted a chart review of Medicare patients aged > or = 65 years with a history of atrial fibrillation before a hospitalization during the first 6 months of 1994. RESULTS: Among 488 patients (308 women; 457 white; 173 aged > or = 85 years), 38% (184/488) had a relative contraindication to anticoagulation (history of bleeding, dementia, alcohol use, falls, cancer, or the need for nonsteroidal anti-inflammatory drugs). Among the remaining patients (with known atrial fibrillation, but without a contraindication), only 38% (117/304) had been prescribed warfarin. Of those not prescribed warfarin, 63% (117/187) were also not taking aspirin. There were 272 patients with at least one additional vascular risk factor and no contraindication to anticoagulation. Among these patients at moderate to high risk for stroke, anticoagulation had been prescribed in 40% (109/272). Overal, among those not prescribed warfarin, 58% (95/163) were not taking aspirin. Patients admitted with a stroke were more likely to be significantly underanticoagulated (with international normalized ratio < 1.5) (43.5% versus 20.9% for those without stroke; P < .005). Anticoagulation was most effective for those with an international normalized ratio > or = 2.0. CONCLUSIONS: Warfarin anticoagulation with atrial fibrillation, even among "ideal" candidates, appears dramatically underutilized. In addition, among those prescribed warfarin, patients are often undertreated. Increased warfarin use among patients with atrial fibrillation represents an excellent opportunity for stroke prevention in the elderly.

Aged↗
PubMed1996

Intracranial hemorrhage associated with cocaine abuse: a prospective autopsy study.

OBJECTIVES: To determine the incidence of cocaine abuse in cases of fatal intracranial hemorrhage and to examine potential pathophysiologic mechanisms. DESIGN: Prospective clinical, autopsy, and toxicologic evaluation of all cases of fatal non-traumatic intracranial hemorrhage examined during 1 year (April 11, 1989 to April 10, 1990) at the Connecticut Office of the Chief Medical Examiner. Autopsy examination included exhaustive histologic evaluation of cerebral vessels and parenchyma for vasculitis and other vasculopathies. RESULTS: Ten of 17 (59%) of all non-traumatic intracranial hemorrhages were associated with a positive toxicology for cocaine. Seven (70%) of these were parenchymal hemorrhages, and the remaining three (30%) were subarachnoid hemorrhages (ruptured berry aneurysms). No vasculitis or other vasculopathy was identified. CONCLUSIONS: These findings implicate cocaine use as a significant risk factor for fatal brain hemorrhage and may explain, in part, the increased incidence of hemorrhagic stroke in some drug-using cohorts. The lack of specific pathologic findings suggests that cocaine-associated intracranial hemorrhages are a consequence of the pharmacodynamic effect of cocaine and not a cocaine-induced vasculopathy.

Adult↗
PubMed1996

Importance of cerebrovascular disease in studies of myocardial infarction.

BACKGROUND AND PURPOSE: Myocardial infarction and stroke are both predominantly manifestations of atherosclerosis, yet stroke is commonly ignored in prognostic studies and therapeutic trials of ischemic heart disease. Our objective was to assess, in a community setting, the relative importance of stroke among patients at high risk for myocardial infarction. METHODS: We analyzed 1985 survey data from the National Academy of Science Twin Registry of white male veterans. To minimize confounding by genetic and environmental factors, we restricted our analysis to the rates of stroke and myocardial infarction among monozygotic twins counted as individuals or as twin pairs. RESULTS: Among 2764 monozygotic twins aged 58 to 68 years, the overall rate of myocardial infarction was 10% and stroke 3.1%. Among 2632 individual monozygotic twins (95%) with complete responses, the rate of stroke among men with a history of myocardial infarction was 7.5% (17/228) compared with 2.4% (58/2404) among those without myocardial infarction (odds ratio = 3.3, chi square 2 = 19.1, P<.001). A strong association between stroke and myocardial infarction was also found when the data were analyzed for twin pairs (chi square 2 = 135, P<.0005). CONCLUSIONS: Our results suggest that stroke, in addition to myocardial infarction, should be considered as an outcome in clinical investigations of ischemic heart disease.

Aged↗
PubMed1995

SPECT imaging of stroke.

Single-photon emission computed tomography (SPECT) is a helpful tool for the management of stroke patients. Brain perfusion SPECT can help differentiate an ischemic event from peri-ictal phenomena such as Todd's paresis. Initial data suggest that SPECT may be useful in prognosticating the likelihood of an early stroke after a transient ischemic attack and in distinguishing lacunar from cortical stroke. After an acute stroke, early SPECT depicts the area of ischemia with greater accuracy than either computed tomography or magnetic resonance imaging. When the perfusion defect is large, the likelihood of hemorrhagic complications or herniation increases. Reperfusion of an arterial territory after thrombolysis can be documented more conveniently with SPECT than with angiography. SPECT before and after the injection of acetazolamide has been used to assess the vascular reserve in patients with severe stenosis of the proximal vessels of the cerebrovascular tree. Combined with transcranial Doppler studies, SPECT is used to document ischemia after subarachnoid hemorrhage. It has also been used to assess the effect of arterial ligation intended to treat arteriovenous malformations or aneurysms on brain perfusion and to evaluate ischemia secondary to pressure from an intracranial hemorrhage.

Brain Ischemia↗
PubMed1995

Clinical correlates of proton magnetic resonance spectroscopy findings after acute cerebral infarction.

BACKGROUND AND PURPOSE: We sought to determine whether lactate and N-acetyl signals measured by proton magnetic resonance spectroscopy (MRS) in the first days after stroke correlate with clinical measures of disability and functional outcome. METHODS: One-dimensional spectroscopic imaging was performed after stroke on 32 patients using a 2.1-T magnet. The Toronto Stroke Scale score at the time of the MRS study and the Barthel Index score at hospital discharge were determined from patient records. Lesion volume was estimated by a tracing algorithm from the scout magnetic resonance image obtained as part of the MRS study. The scaled lactate and N-acetyl signals from the voxel having the highest measured lactate were used to predict the clinical variables and lesion volume, as well as relative perfusion within the lesion, in those patients who underwent single-photon emission computed tomography (SPECT) blood flow imaging, using a multiple regression analysis. The correlation of lesion volume with the clinical variables was also evaluated. RESULTS: Lesion lactate signal was correlated with the Toronto Stroke Scale score, Barthel Index score, lesion volume, and SPECT score, all at P < .01. The N-acetyl level correlated with the Barthel Index score and lesion volume at P < .05. Lesion volume was also strongly correlated with the clinical variables (P < .0001). CONCLUSIONS: This is the first study to document the clinical predictive value of proton MRS measurements in patients after stroke. The association with functional outcome is stronger for lactate than for N-acetyl. Spectroscopic assessment of the metabolic status of cerebral tissues shortly after infarction may have significant clinical utility.

Acetates↗
PubMed1995

Sex differences in the management of patients hospitalized with ischemic cerebrovascular disease.

BACKGROUND AND PURPOSE: Previous studies suggest that the management of coronary artery disease differs for women compared with men. We examined this issue for ischemic cerebrovascular disease. METHODS: We reviewed the use of angiography and carotid endarterectomy among patients discharged from Connecticut hospitals during 6 years over the past decade. Crude and age-adjusted rates of angiography and endarterectomy were determined for each sex. RESULTS: Among 22,582 female and 19,729 male patients discharged, the rate of cerebral angiography was 11.8% for men and 7.2% for women; the age-adjusted odds ratio was 0.77 (95% confidence interval [CI], 0.72 to 0.82). The rate of endarterectomy was 10.6% for men and 5.7% for women; the age-adjusted odds ratio was 0.67 (95% CI, 0.62 to 0.72). The distribution of cerebrovascular disease type differed by sex, however, with carotid artery disease representing a larger proportion of men (12.2% [2415/19,729]) than women (6.9% [1554/22,582]) (chi 2 = 355.8, P < .0001). When restricted to this diagnosis, no sex differences exist (odds ratio for angiography, 1.00 [95% CI, 0.87 to 1.14] and for endarterectomy, 0.93 [95% CI, 0.81 to 1.07]). CONCLUSIONS: Overall, women hospitalized for ischemic cerebrovascular disease undergo fewer angiograms and are less likely to have carotid endarterectomy than men. These differences are not found when analysis is restricted to subjects with carotid disease and suggest that part of the difference in management may be due to biological differences between men and women.

Aged↗