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Biomedical subjects

Lee H Schwamm

Publications and source records attributed to Lee H Schwamm.

At least 19 recordsLinked to original sources
PubMed2006

Guidelines for prevention of stroke in patients with ischemic stroke or transient ischemic attack: a statement for healthcare professionals from the American Heart Association/American Stroke Association Council on Stroke: co-sponsored by the Council on Cardiovascular Radiology and Intervention: the American Academy of Neurology affirms the value of this guideline.

The aim of this new 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 for the implementation of guidelines and their use in high-risk populations.

American Heart Association↗
PubMed2006

Risk factors for stroke after acute coronary syndromes in the Orbofiban in Patients with Unstable Coronary Syndromes--Thrombolysis In Myocardial Infarction (OPUS-TIMI) 16 study.

BACKGROUND: Previous reports have associated acute coronary syndromes (ACSs) with cerebrovascular disease but in general have not included long-term patient follow-up or have not analyzed ischemic and hemorrhagic cerebrovascular events separately. METHODS: We analyzed stroke outcomes from the OPUS-TIMI 16 study, a multicenter, randomized, placebo-controlled trial. Patients were randomized to aspirin plus either orbofiban or placebo and followed for up to 1 year. Cerebrovascular events were prospectively identified and classified by a committee of cardiologists and neurologists blinded to treatment assignment. RESULTS: During 10 months of follow-up, there were 150 (1.5%) patients with cerebrovascular events. Risk factors for ischemic stroke (n = 67) and transient ischemic attack (TIA) (n = 44) were age, prior ischemic stroke, history of hypertension, and increased heart rate. Prior ischemic stroke and history of hypertension were not risk factors for 30-day ischemic stroke or TIA. Risk factors for intracranial hemorrhage (ICH) (n = 14) were age, history of hypertension, history of TIA, and coronary angiography with evidence of coronary artery disease. Compared with placebo, treatment with orbofiban was associated with a nonsignificant increased risk of ischemic stroke or TIA (HR 1.15, 95% CI 0.76-1.74, P = .51) and ICH (HR 1.25, 95% CI 0.39-4.00, P = .70). CONCLUSIONS: The overall incidence of cerebrovascular events after ACS was highest in the first 30 days then declined; risk factors for cerebrovascular events may be different in the different periods. Orbofiban, despite no significant excess risk of ICH, was not effective in preventing ischemic stroke or TIA.

Aged↗
PubMed2006

Guidelines for prevention of stroke in patients with ischemic stroke or transient ischemic attack: a statement for healthcare professionals from the American Heart Association/American Stroke Association Council on Stroke: co-sponsored by the Council on Cardiovascular Radiology and Intervention: the American Academy of Neurology affirms the value of this guideline.

The aim of this new 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 for the implementation of guidelines and their use in high-risk populations.

Adult↗
PubMed2005

Poor outcomes in patients who do not receive intravenous tissue plasminogen activator because of mild or improving ischemic stroke.

BACKGROUND AND PURPOSE: Some patients with mild or improving ischemic stroke symptoms do not receive intravenous tissue plasminogen activator (tPA) because they look "too good to treat" (TGT); however, some have poor outcomes. METHODS: We retrospectively analyzed data from a prospective single-center study between 2002 and 2004. TGT patients were those arriving within 3 hours of symptom onset and not treated with intravenous tPA solely because of mild or improving symptoms. RESULTS: Of 128 patients presenting within 3 hours, 41 (34%) were not given tPA because of mild or improving stroke. Of the TGT patients, 11 of 41 (27%) died or were not discharged home because of neurological worsening (n=6) or persistent "mild" neurological deficit (n=5). No single variable at presentation was associated with death or lack of home discharge. There were 10 of 41 TGT patients (24%) who had > or =4-point improvement in National Institutes of Health Stroke Scale score before tPA decision; these patients were more likely to have subsequent neurological worsening (relative risk, 4.1, 95% CI, 1.1 to 15.4; P=0.05). CONCLUSIONS: A substantial minority of patients deemed too good for intravenous tPA were unable to be discharged home. A re-evaluation of the stroke severity criteria for tPA eligibility may be indicated.

Aged↗
PubMed2005

Transient ischemic attack with infarction: a unique syndrome?

It is debated whether transient symptoms associated with infarction (TSI) are best considered a minor ischemic stroke, a subtype of transient ischemic attack (TIA), or a separate ischemic brain syndrome. We studied clinical and imaging features to establish similarities and differences among ischemic stroke, TIA without infarction, and TSI. Eighty-seven consecutive patients with TIA and 74 patients with ischemic stroke were studied. All underwent diffusion-weighted imaging on admission. Symptom duration and infarct volume were determined in each group. Thirty-six patients (41.3%) with TIA had acute infarct(s). Although TIA-related infarcts were smaller than those associated with ischemic stroke (mean, 0.7 vs 27.3 ml; p < 0.001), there was no lesion size threshold that distinguished ischemic stroke from TSI. In contrast, the symptom duration probability density curve was not broad, but instead peaked early with only a few patients having symptoms for longer than 200 minutes. The probability density function for symptom duration was similar between TIA with or without infarction. The in-hospital recurrent ischemic stroke and TIA rate was 19.4% in patients with TSI and 1.3% in those with ischemic stroke. TIA with infarction appears to have unique features separate from TIA without infarction and ischemic stroke. We propose identifying TSI as a separate clinical syndrome with distinct prognostic features.

Aged↗
PubMed2005

The evolving role of acute stroke imaging in intravenous thrombolytic therapy: patient selection and outcomes assessment.

In early trials of thrombolysis, unenhanced CT was used to exclude patients with brain hemorrhage or large infarctions but was insensitive to stroke pathophysiology or early signs of cerebral ischemia or infarction. Currently, CT angiography, CT perfusion, and MR imaging can provide information about stroke mechanisms and prognosis, quantify penumbral tissue, and support risk stratification and patient selection. This article reviews the role of neuroimaging in the original intravenous thrombolytic trials, current application of these technologies, and the potential future role of imaging to extend the time window for thrombolysis and to augment therapeutic success.

Acute Disease↗
PubMed2005

Arterial occlusion revealed by CT angiography predicts NIH stroke score and acute outcomes after IV tPA treatment.

BACKGROUND AND PURPOSE: The relationship between location of occlusion and clinical outcome is poorly understood in patients receiving intravenous tissue-type plasminogen activator (IV tPA). We postulated that acute stroke patients receiving IV tPA with patent vasculature or occult arterial occlusion by CT angiography (CTA) would have better outcomes and decreased hemorrhagic risk. METHODS: We identified 47 patients from our prospective stroke database who underwent CTA before treatment with IV tPA. Site of occlusion was categorized as M1 segment of the middle cerebral artery, M2 segment, multiple (either carotid, basilar, or both middle and anterior cerebral arteries), or absent (no occlusion proximal to M3). The effect of site of occlusion on National Institutes of Health Stroke Scale (NIHSS), early improvement (> or = 4-point improvement in NIHSS at 24 hours after treatment), intracranial hemorrhages, and modified Rankin scale (mRS) at 7 days was tested in a multivariate analysis. RESULTS: The location of occlusion correlated with initial NIHSS for multiple, M1, M2 and absent occlusions (median NIHSS scores were 18, 18, 15, 10, respectively) (P < .02, rank sum). Following adjustment for initial NIHSS, age, and time to treatment, the absence of occlusion remained associated with early improvement (OR 5.0, 95% CI 1.1-23.3; P = .04) and independence at day 7 (mRS < or = 2) (OR 6.8, 95% CI 1.3-34.6; P = .02). Overall prevalence of symptomatic hemorrhages was 6.4%. Patients without occlusion had no hemorrhages (0% versus 23.3%; P < .04). CONCLUSION: Among patients treated with tPA, those with patent vasculature or occult distal occlusion on CTA before treatment have lower NIHSS, better chances of early improvement and early independence with fewer hemorrhages.

Aged↗
PubMed2005

Hypoattenuation on CT angiographic source images predicts risk of intracerebral hemorrhage and outcome after intra-arterial reperfusion therapy.

BACKGROUND AND PURPOSE: Symptomatic hemorrhagic transformation (HT) is a significant complication of intravenous and catheter-based reperfusion. We hypothesized that the degree of vascular insufficiency, reflected as hypoattenuation on initial CT angiography (CTA) axial source images, is predictive of HT risk in stroke patients receiving intra-arterial reperfusion therapy. METHODS: We examined initial CTA source images and follow-up CT scans in 32 consecutive patients. Regions of interest were semiautomatically segmented and reviewed. Mean intensity was determined in the region of maximal hypoattenuation and in normal contralateral tissue, and the arithmetic difference (deltaHU) calculated. Receiver operator characteristic (ROC) curves and cross-validation were used to identify threshold deltaHU values. RESULTS: Thirteen patients had HT on follow-up CT (seven with parenchymal hematoma, six with hemorrhagic infarction). Patients with and those without HT did not differ in age, blood glucose level, lesion volume, or time to treatment or recanalization, though the former had a greater mean deltaHU (9.0 vs 6.3, P = .006). The ROC threshold at deltaHU > or = 8.1 was 69% sensitive and 90% specific for patients who developed HT (odds ratio = 19.1; 95% confidence interval: 2.9, 125; P = .002) and was predictive of poor clinical outcome (modified Rankin scale score > 2, P = .03). Neither HT in general nor parenchymal hematoma subtype was associated with poor outcome. CONCLUSION: The degree of hypoattenuation on initial CTA source images is a risk factor for HT and poor clinical outcome after intra-arterial reperfusion therapy. Prospective validation of this relationship in large populations may permit feasible real-time risk stratification.

Aged↗
PubMed2004

ASPECTS on CTA source images versus unenhanced CT: added value in predicting final infarct extent and clinical outcome.

BACKGROUND AND PURPOSE: The Alberta Stroke Program Early CT Score (ASPECTS) is a grading system to assess ischemic changes on CT in acute ischemic stroke. CT angiography-source images (CTA-SI) predict final infarct volume. We examined whether the final infarct ASPECTS and clinical outcome were more related to acute CTA-SI ASPECTS than to the acute noncontrast CT (NCCT) ASPECTS. METHODS: ASPECTS was assigned by 2 raters on the acute NCCT, CTA-SI, and follow-up imaging. The mean baseline ASPECTS of acute NCCT and CTA-SI was compared with the follow-up ASPECTS. Rate ratios (RRs) were used to quantify the relationship between the dichotomized baseline ASPECTS (categorized as 0 to 7 versus 8 to 10) and favorable patient outcome. RESULTS: Thirty-nine patients were recruited. Proximal occlusion (internal carotid artery or middle cerebral artery) was seen in 62%, M2 occlusion in 18%, and no occlusion was seen in 20% of patients. The median time between symptom onset and imaging was 1.9 (1.2 to 2.5) hours. There was a significantly larger difference of 1.4 between the mean baseline NCCT and CTA-SI ASPECTS in patients who had more ischemic changes (follow-up ASPECTS=0 to 3) than a difference of 0.6 in patients who had near-to-normal CT scans (follow-up ASPECTS=8 to 10). The rate of favorable outcome for acute NCCT ASPECTS of 8 to 10 was 51.8% versus 25.0% for 0 to 7 (RR, 2.1, 95% CI: 0.7 to 5.9, P=0.12). For acute CTA-SI ASPECTS of 8 to 10, the rate of favorable outcome was 58.8% versus 31.8% for 0 to 7 (RR, 1.8, 95% CI: 0.9 to 3.8, P=0.09). CONCLUSIONS: CTA-SI ASPECTS provides added information in the prediction of final infarct size.

Aged↗
PubMed2004

Diffusion-weighted MR imaging in closed head injury: high correlation with initial glasgow coma scale score and score on modified Rankin scale at discharge.

PURPOSE: To determine whether diffusion-weighted magnetic resonance (MR) imaging findings and conventional MR imaging findings correlate with initial Glasgow Coma Scale score and score on modified Rankin scale at discharge. MATERIALS AND METHODS: Twenty-six patients (18 male and eight female patients; mean age, 25.2 years; age range, 4-72 years) with diffuse axonal injury were examined with diffusion-weighted MR imaging and with fluid-attenuated inversion recovery, T2-weighted fast spin-echo, and T2*-weighted gradient-echo sequences. All images were evaluated by two neuroradiologists in consensus. Tissue volume with trauma-related signal-intensity abnormality on images from each sequence, number of lesions for each sequence, number of lesions for all sequences, and number of lesions with reduced apparent diffusion coefficient were correlated with scores on Glasgow Coma Scale and modified Rankin scale. Involvement of brainstem, deep gray matter, and corpus callosum were also correlated with clinical scores. Spearman rank correlation coefficients (r) were calculated. RESULTS: The strongest correlation was between signal-intensity abnormality volume on diffusion-weighted images and modified Rankin score (r = 0.772, P <.001). The strength of this correlation did not improve when only volume of lesions with decreased apparent diffusion coefficient was considered. For lesion number, the strongest correlation was between lesion number on images acquired with all sequences and modified Rankin score (r = 0.662, P <.001). For lesion location, the strongest correlation was between lesion location in the corpus callosum and modified Rankin score (r = 0.513, P =.007). CONCLUSION: Volume of lesions on diffusion-weighted MR images provides the strongest correlation with a score of subacute on modified Rankin scale at discharge. Total lesion number also correlates well with modified Rankin score. In future, diffusion-weighted images may be useful in determining treatment strategies for acute head injury.

Adolescent↗