Biomedical subjects

Karen L Furie

Publications and source records attributed to Karen L Furie.

17 recordsLinked to original sources

PubMed2006

The changing risk factor profile of participants enrolled in a secondary stroke prevention trial: Vitamin intervention for stroke prevention.

OBJECTIVE: To determine if the stroke risk factor profile of participants in a large, multicenter secondary stroke prevention trial changed over the recruitment period. METHODS: The 3,680 participants in the Vitamin Intervention for Stroke Prevention (VISP) were categorized into four groups by enrollment date. Baseline patient characteristics and stroke risk factors were compared across groups. RESULTS: Hypertension and hypercholesterolemia management improved but prevalence of three major stroke risk factors did not change. Patients enrolled later had better Mini-Mental State and lower NIH Stroke Scale scores, higher multivitamin use, lower prevalence of cortical infarctions, cardiac symptoms and prior stroke, and lower serum creatinine levels. CONCLUSIONS: Those participants enrolled in the later recruitment periods had a different risk factor profile and risk factors were managed differently compared to those enrolled earlier.

Adult↗

PubMed2006

Bright and black blood imaging of the carotid bifurcation at 3.0T.

PURPOSE: The aim of this study was to evaluate our preliminary experience at 3.0 T with imaging of the carotid bifurcation in healthy and atherosclerotic subjects. Application at 3.0 T is motivated by the signal-to-noise gain for improving spatial resolution and reducing signal averaging requirements. MATERIALS AND METHODS: We utilized a dual phased array coil and applied 2D, 3D time of flight (TOF) and turbo spin echo (TSE) sequences with comparison of two lumen signal suppression methods for black blood (BB) TSE imaging including double inversion preparation (DIR) and spatial presaturation pulses. The signal-to-noise ratios (SNR) of healthy carotid vessel walls were compared in 2D and 3D BB TSE acquisitions. The bright and black blood multi-contrast exam was demonstrated for a complex carotid plaque. RESULTS: Contrast-to-noise (CNR) greater than 150 was achieved between the lumen and suppressed background for 3D TOF. For BB, both methods provided sufficient lumen signal suppression but slight residual flow artifacts remained at the bifurcation level. As expected 3D TSE images had higher SNR compared to 2D, but increased motion sensitivity is a significant issue for 3D at high field. For multi-contrast imaging of atherosclerotic plaque, fibrous, calcified and lipid components were resolved. The CNR ratio of fibrous (bright on PDW, T2W) and calcified (dark in T1W, T2W, PDW) plaque components was maximal in the T2W images. The 3D TOF angiogram indicating a 40% stenosis was complemented by 3D multi-planar reformat of BB images that displayed plaque extent. Detection of intimal thickening, the earliest change associated with atherosclerotic progression was observed in BB PDW images at 3.0 T. CONCLUSIONS: High SNR and CNR images have been demonstrated for the healthy and diseased carotid. Improvements in RF coils along with pulse sequence optimization, and evaluation of endogenous and exogenous contrast mechanisms will further enhance carotid imaging at 3.0T.

Adult↗

PubMed2006

Intra- and interreader reproducibility of magnetic resonance imaging for quantifying the lipid-rich necrotic core is improved with gadolinium contrast enhancement.

PURPOSE: To test the hypothesis that intra- and interreader reproducibility for measuring the lipid-rich necrotic core (LR-NC) size is significantly improved with gadolinium (Gd) contrast-enhanced magnetic resonance imaging (CEMRI) compared to non-CEMRI. MATERIALS AND METHODS: Thirty-seven individuals with >50% carotid artery stenosis underwent carotid MRI at 1.5T (pre- and postcontrast T1-weighted (T1W), T2-weighted (T2W), proton density-weighted (PDW), and three-dimensional time-of-flight (TOF) sequences). Two independent readers measured the mean area of the LR-NC from the precontrast images only, followed by a second measurement using the additional postcontrast images. One reader repeated the measurements after an interval of five months. Intra- and interreader reproducibility was analyzed by means of the intraclass correlation coefficient (ICC), coefficient of variation (CV), and standard deviation (SD). RESULTS: The CV decreased from 33.7% to 8.8% for intrareader measurements of the LR-NC, and from 33.5% to 17.6% for interreader measurements. The SD was significantly smaller with CEMRI than with non-CEMRI (P = 0.003 and P = 0.006, respectively). The ICC increased from 0.94 to 0.99 and from 0.85 to 0.93 for the intra- and interreader measurements, respectively. CONCLUSION: Reader reproducibility for in vivo MRI quantification of LR-NC size is significantly improved by the addition of Gd contrast in individuals with >50% carotid stenosis.

Arteries↗

PubMed2006

Homocyst(e)ine and stroke.

Homocyst(e)ine elevation is associated with a two- to threefold fold increased risk of ischemic stroke. Although most commonly associated with large-artery atherosclerosis and venous thrombosis, hyperhomocysteinemia may contribute to stroke by other mechanisms as well. Levels of homocysteine are determined by genetic regulation of the enzymes involved in homocyst(e)ine metabolism and by levels of the vitamin cofactors (folate, B (6), and B (12)) associated with those reactions. Emerging evidence suggests that genetic variation within this pathway, such as the methyleneterahydrofolate reductase and cystathionine beta-synthase and nicotinamide N-methyltransferase genes, increases the risk of ischemic stroke. The introduction of grain folate fortification in 1998 has reduced homocyst(e)ine concentrations in the U.S. population. However, it is important to screen for vitamin B (12) deficiency and be cognizant that vitamin B (6) levels may be low in the elderly and in individuals with inflammatory disorders. The Vitamin Intervention in Stroke Prevention study failed to prove that high-dose supplementation with folate, B (6), and B (12) reduced the risk of recurrent stroke or myocardial infarction at 2 years; however, there is an ongoing clinical trial evaluating the potential benefit of vitamin supplementation.

Clinical Trials as Topic↗

PubMed2006

Vulnerable plaque detection by 3.0 tesla magnetic resonance imaging.

RATIONALE AND OBJECTIVES: A clinical case report is presented on a 76-year-old man who volunteered for a 3.0 T magnetic resonance (MR) carotid protocol. The subject was referred for carotid endarterectomy and histology was performed on the ex vivo specimen and compared with the in vivo images. METHODS: The 3.0 and 1.5 T (obtained for comparison) MR protocol consisted of 2-dimensional (2D) and 3-dimensional (3D) multicontrast bright and black blood imaging for detecting the lumen and vessel wall. RESULTS: The combination of multicontrast black blood transverse images and the 3D time of flight transverse images provided visualization of a narrowed internal carotid artery lumen 4 mm above of the bifurcation and the presence of a complex atherosclerotic plaque containing a large lipid pool, calcification, and intact fibrous cap. Quantitative comparisons including vessel lumen and plaque area, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were obtained for 1.5 and 3.0 T image data. Plaque composition was verified with histology. Macrophages were also detected in the shoulders of the plaque as demonstrated by CD68 staining and corresponded with a small hyperintense area in the T2W images at 3.0 T, but not observed in comparable 1.5 T images. CONCLUSIONS: High field 3.0 T multicontrast MRI of atherosclerotic plaque has been validated with histology comparison and provides improved detection of complex atherosclerotic plaque with increased SNR and CNR compared with 1.5 T. Further studies validating contrast mechanisms of plaque at 3.0 T are required, but atherosclerotic plaque imaging has clear benefit from application at the higher magnetic field strength.

Aged↗

PubMed2006

Ask the doctor. For the last few years, I have been experiencing what I think are mini-strokes. The first time it happened, I lost the sight in one eye for about a minutes. Sometimes the vision in both eyes gets blurred for a few minutes. A few weeks ago I could not think of the word "battery" while talking with a friend. Otherwise, I am a healthy 77-year-old who exercises, isn't overweight, and doesn't smoke. My doctor hasn't suggested any tests of courses of action. Can you?

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Aged↗

PubMed2005

Dose-related association of MTHFR 677T allele with risk of ischemic stroke: evidence from a cumulative meta-analysis.

BACKGROUND: Data are conflicting concerning ischemic stroke risk associated with a common polymorphism in the gene encoding 5,10-methylenetetrahydrofolate reductase (MTHFR 677C-->T), which predisposes to hyperhomocystinemia in vivo. METHODS: We performed a systematic review and meta-analysis of published relevant literature. We included cohort, case-control, or cross-sectional studies reporting the frequencies of heterozygous (CT) and homozygous (TT) genotypes in (a) all stroke/TIA (overall group) and (b) imaging-proven ischemic stroke (best-phenotyped group). RESULTS: Among 14 870 subjects, the pooled estimated risk of stroke/TIA associated with the 677T allele increased in a dose-dependent manner (T allele pooled OR 1.17, 95%CI 1.09 to 1.26, TT genotype pooled OR 1.37, 95%CI 1.15 to 1.64). An almost-identical relationship was observed when the analysis was restricted to imaging-proven ischemic stroke (T allele pooled OR 1.18, 95%CI 1.09 to 1.29, TT genotype pooled OR 1.48, 95%CI 1.22 to 1.8). CONCLUSIONS: A graded increase in ischemic stroke risk with increasing MTHFR 677T allele dose was observed, suggesting an influence of this polymorphism as a genetic stroke risk factor and supporting other evidence indicating a causal relationship between elevated homocysteine and stroke.

Adult↗

PubMed2005

An evidence-based causative classification system for acute ischemic stroke.

Regular, evidence-based assignment of patients to etiologic stroke categories is essential to enable valid comparison among studies. We designed an algorithm (SSS-TOAST) that incorporated recent advances in stroke imaging and epidemiology to identify the most probable TOAST category in the presence of evidence for multiple mechanisms. Based on the weight of evidence, each TOAST subtype was subdivided into 3 subcategories as "evident", "probable", or "possible". Classification into the subcategories was determined via predefined specific clinical and imaging criteria. These criteria included published risks of ischemic stroke from various mechanisms and published reports of the strength of associations between clinical and imaging features and particular stroke mechanisms. Two neurologists independently assessed 50 consecutively admitted patients with acute ischemic stroke through reviews of abstracted data from medical records. The number of patients classified as "undetermined-unclassified" per the original TOAST system decreased from 38-40% to 4% using the SSS-TOAST system. The kappa value for inter-examiner reliability was 0.78 and 0.90 for the original TOAST and SSS-TOAST respectively. The SSS-TOAST system successfully classifies patients with acute ischemic stroke into determined etiologic categories without sacrificing reliability. The SSS-TOAST is a dynamic algorithm that can accommodate modifications as new epidemiological data accumulate and diagnostic techniques advance.

Adult↗

PubMed2004

Mechanisms of hemorrhagic transformation after tissue plasminogen activator reperfusion therapy for ischemic stroke.

Reperfusion therapy with tissue plasminogen activator (tPA) is a rational therapy for acute ischemic stroke. Properly titrated use of tPA improves clinical outcomes. However, there is also an associated risk of hemorrhagic transformation after tPA therapy. Emerging data now suggest that some of these potentially neurotoxic side effects of tPA may be due to its signaling actions in the neurovascular unit. Besides its intended role in clot lysis, tPA is also an extracellular protease and signaling molecule in brain. tPA mediates matrix remodeling during brain development and plasticity. By interacting with the NMDA-type glutamate receptor, tPA may amplify potentially excitotoxic calcium currents. At selected concentrations, tPA may be vasoactive. Finally, by augmenting matrix metalloproteinase (MMP) dysregulation after stroke, tPA may degrade extracellular matrix integrity and increase risks of neurovascular cell death, blood-brain barrier leakage, edema, and hemorrhage. Understanding these pleiotropic actions of tPA may reveal new therapeutic opportunities for combination stroke therapy.

Animals↗

PubMed2004

Preventing a second stroke in the young.

In the United States, more than 220,000 adults under the age of 45 have had a stroke. Secondary stroke prevention is critical in this population because of the potential impact of a second stroke on productivity and future quality of life. In addition to conventional stroke risk factors, younger patients have special risk factors inherent to genetic and environmental elements, such as the use of illicit drugs and cardiac abnormalities; in women, risk factors include pregnancy, migraine, and the use of oral contraceptives.

Adult↗

PubMed2003

Increased pelvic vein thrombi in cryptogenic stroke: results of the Paradoxical Emboli from Large Veins in Ischemic Stroke (PELVIS) study.

BACKGROUND AND PURPOSE: Cryptogenic stroke is associated with an increased prevalence of patent foramen ovale. The Paradoxical Emboli From Large Veins in Ischemic Stroke (PELVIS) study hypothesized that patients with cryptogenic stroke have an increased prevalence of pelvic deep venous thrombosis (DVT). METHODS: At 5 sites, patients 18 to 60 years of age received an MRI venogram (MRV) of the pelvis within 72 hours of new symptom onset. Clinical data were then determined. Radiologists blinded to clinical data later read the scans. RESULTS: The 95 patients who met entry criteria were scanned. Their mean+/-SD age was 46+/-10 years, and time from stroke onset to pelvic MRV scan was 49+/-16 hours. Compared with those with stroke of determined origin (n=49), patients with cryptogenic stroke (n=46) were significantly younger, had a higher prevalence of patent foramen ovale (61% versus 19%), and had less atherosclerosis risk factors. Cryptogenic patients had more MRV scans with a high probability for pelvic DVT (20%) than patients with stroke of determined origin (4%, P<0.03), with most having an appearance of a chronic DVT. CONCLUSIONS: In this study of young stroke patients evaluated early after stroke, patients with cryptogenic stroke showed differences in several clinical features compared with patients with stroke of determined origin, including increased prevalence of pelvic DVT. The results require confirmation but suggest that paradoxical embolus from the pelvic veins may be the cause of stroke in a subset of patients classified as having cryptogenic stroke.

Adolescent↗

PubMed2003

Low vitamin B6 but not homocyst(e)ine is associated with increased risk of stroke and transient ischemic attack in the era of folic acid grain fortification.

BACKGROUND AND PURPOSE: The introduction of cereal grain folic acid fortification in 1998 has reduced homocyst(e)ine (tHcy) concentrations in the US population. We performed a case-control study to determine the risk of stroke and transient ischemic attack (TIA) associated with tHcy and low vitamin status in a postfortification US sample. METHODS: Consecutive cases with new ischemic stroke/TIA were compared with matched controls. Fasting tHcy, folate, pyridoxal 5'-phosphate (PLP), B12, and MTHFR 677C-->T genotype were measured. RESULTS: Mean PLP was significantly lower in cases than controls (39.97 versus 84.1 nmol/L, P<0.0001). After stroke risk factors were controlled for, a strong independent association was present between stroke/TIA and low PLP (adjusted odds ratio [OR], 4.6; 95% CI, 1.4 to 15.1; P<0.001) but not elevated tHcy (OR, 0.92; 95% CI, 0.4 to 2.1). CONCLUSIONS: Low B6 but not tHcy was strongly associated with cerebrovascular disease in this postfortification, folate-replete sample.

Case-Control Studies↗

PubMed2003

Functional recovery following rehabilitation after hemorrhagic and ischemic stroke.

OBJECTIVES: To quantify recovery after rehabilitation therapy and to identify factors that predicted functional outcome in survivors of intracerebral hemorrhage (ICH) compared with cerebral infarction. DESIGN: Retrospective study of consecutive ICH and cerebral infarction admissions to a rehabilitation hospital over a 4-year period. SETTING: Free-standing urban rehabilitation hospital. PARTICIPANTS: A total of 1064 cases met the inclusion criteria (545 women, 519 men; 871 with cerebral infarction, 193 with ICH). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Functional status was measured using the FIM trade mark instrument, recorded at admission and discharge. Recovery was quantified by the change in FIM total score (DeltaFIM total score). Outcome measures were total discharge FIM score and DeltaFIM total score. Univariate and multivariate analyses were performed. RESULTS: Total admission FIM score was higher in patients with cerebral infarction than in patients with ICH (59 vs 51, P=.0001). No difference in total discharge FIM score was present. Patients with ICH made a significantly greater recovery than those with cerebral infarction (DeltaFIM total score, 28 vs 23.3; P=.002). On multivariate analysis, younger age, longer length of stay, and admission FIM cognitive subscore independently predicted total discharge FIM and DeltaFIM total score. The severity of disability at admission, indicated by total admission FIM score, independently predicted total discharge FIM score, but not DeltaFIM total score. The ICH patients with the most severely disabling strokes had significantly greater recovery than cerebral infarction patients with stroke of similar severity. CONCLUSIONS: The patients with ICH had greater functional impairment than the cerebral infarction patients at admission, but made greater gains. Patients with the most severely disabling ICH improved more than those with cerebral infarction of comparable severity. Initial severity of disability, age, and duration of therapy best predicted functional outcome after rehabilitation.

Activities of Daily Living↗

PubMed2003

Family member knowledge and expectations for functional recovery after stroke.

OBJECTIVE: To assess the stroke knowledge and expectations for recovery among the family members of stroke patients in an acute rehabilitation hospital. DESIGN: Survey study of 50 family members of stroke patients undergoing inpatient rehabilitation at a single urban rehabilitation hospital. RESULTS: Sixty percent of participants were able to identify whether their family member had sustained a cerebral hemorrhage or infarct; 48% were able to identify at least one treatment provided to their family member for his or her stroke. The average length of stay predicted by participants closely matched the average patient length of stay. Participants tended to overestimate the functional abilities of their family member with a stroke, both on initial assessment and discharge. This overestimation was more substantial for discharge functional ability than for initial assessment. Participants were able to predict discharge location with substantial accuracy (82% agreement, kappa = 0.41). CONCLUSIONS: The knowledge of stroke etiology and functional outcome of family members of individuals undergoing rehabilitation after stroke shows significant limitations. Participants' ability to predict functional outcome on discharge was worse than their knowledge of current functional status. Participant predictions of length of stay and discharge disposition were areas of relative strength. Further efforts are needed to enhance the knowledge level of family members of patients undergoing rehabilitation after stroke.

Adult↗

PubMed2003

Patient knowledge and expectations for functional recovery after stroke.

OBJECTIVE: Understanding the causes and outcomes of stroke is important for stroke survivors and may affect their success in rehabilitation and their risk of recurrent stroke; therefore, this study was performed to assess the knowledge and expectation of functional recovery in stroke patients undergoing acute inpatient rehabilitation. DESIGN: Survey study of 50 consecutive stroke patients undergoing inpatient rehabilitation at a single urban rehabilitation hospital. RESULTS: Forty-six percent of participants were able to correctly identify whether they had sustained a cerebral infarct or hemorrhage. Rehabilitation length of stay was, on average, 1 wk longer than anticipated by patients. Patients overestimated their functional abilities on initial assessment and at discharge compared with staff assessments, with some improvement in accuracy for discharge predictions. Ninety-four percent of participants expected to be discharged home, and most achieved this goal. Although no participant anticipated discharge to a nursing home, 10% of patients were discharged to this location. CONCLUSIONS: Knowledge of stroke and its treatment was limited, and expectations for recovery tended to exceed actual accomplishments. There are significant areas of opportunity for enhanced educational efforts for stroke patients undergoing inpatient rehabilitation.

Activities of Daily Living↗

PubMed2003

Stroke: Effect of implementing an evaluation and treatment protocol compliant with NINDS recommendations.

PURPOSE: To evaluate--relative to routine clinical practice--the potential cost-effectiveness of implementing a strategy compliant with National Institute of Neurological Disorders and Stroke (NINDS) recommendations for care of patients presenting with signs and symptoms of acute ischemic stroke. MATERIALS AND METHODS: A discrete-event simulation model of the process of stroke care from symptom onset through administration of tissue plasminogen activator (tPA) was constructed. A literature review was performed to determine process times, performance of computed tomography (CT), health outcomes, and cost estimates. The following were compared: (a) a "base-case" strategy determined on the basis of findings in the literature and (b) a NINDS-compliant strategy (ie, evaluation by emergency physician in less than 10 minutes, interpretation of CT scans within 45 minutes, and administration of tPA within 1 hour after presentation). Strategies were compared with regard to cost and effectiveness. Sensitivity analyses were performed for all relevant cost, timing, and resource parameters. Outcomes of concern were quality-adjusted life years and number of patients treated within a 3-hour therapeutic window. RESULTS: The NINDS-compliant strategy resulted in an average quality-adjusted life years value of 3.64, versus 3.63 for the base case, at an approximate cost of 434 US dollars per patient. The NINDS-compliant strategy increased the proportion of treatable patients from 1.4% to 3.7% and remained cost-effective for expenditures of up to 450 US dollars per patient. Assuming base-case parameters are used, increasing the number of CT scanners from two to eight raised the proportion of treatable patients to 1.5%. Increasing the number of available neurologists from four to eight raised the proportion to 1.44%. Reducing the time from stroke onset to emergency department arrival by 30 minutes raised the proportion to up to 7.7%. CONCLUSION: Applying NINDS recommendations is potentially cost-effective, although reducing the time from stroke onset to emergency department arrival may be even more so.

Clinical Protocols↗

PubMed2002

'Footprints' of transient ischemic attacks: a diffusion-weighted MRI study.

OBJECTIVE: Diffusion-weighted imaging (DWI) conveys temporal as well as anatomic information about brain infarction, and is therefore well suited to identify ischemic injury that has occurred simultaneously, or closely linked in time, with a transient ischemic attack (TIA). We aimed to determine the proportion and clinical characteristics of patients with TIA who harbor infarction(s) on DWI. METHODS: Using T(2)-weighted imaging (T(2)-WI), fast fluid attenuated inversion recovery (FLAIR), and DWI, we studied 57 consecutive patients presenting with acute focal neurologic symptoms lasting less than 24 h. RESULTS: A hyperintense DWI lesion was identified in a vascular territory appropriate to the symptoms in 27 patients (47%). Lesions judged to be clinically appropriate on T(2)-WI and FLAIR overlapped with a DWI lesion in 41 and 48% of patients, respectively. Independent predictors of infarction on DWI were previous nonstereotypic TIAs, presentation with motor symptoms, and identified stroke mechanism. CONCLUSION: DWI establishes that recent infarction occurs in almost half of patients with the clinical syndrome of TIA and this subgroup is more likely to harbor an underlying cardiac or cerebrovascular abnormality.

Aged↗