Ct/cta may predict risk for recurrent stroke (printer-friendly)

CT/CTA May Predict Risk for Recurrent Stroke (printer-friendly) http://www.medscape.org/viewarticle/758910_print This article is a CME certified activity. To earn credit for this activity visit:
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CME Information
CME Released: 02/21/2012; Valid for credit through 02/21/2013
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This article is intended for primary care clinicians, neurologists, and other specialists caring for patients withtransient ischemic attack or minor stroke.
The goal of this activity is to provide medical news to primary care clinicians and other healthcare professionals inorder to enhance patient care.
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Upon completion of this activity, participants wil be able to: 1. Describe the ability of computed tomography and computed tomography angiographic imaging to predict recurrent stroke in patients with transient ischemic attack or minor stroke.
2. Compare the prediction of recurrent stroke with use of computed tomography and computed tomography angiographic imaging vs that of magnetic resonance diffusion-weighted imaging.
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CT/CTA May Predict Risk for Recurrent Stroke (printer-friendly) http://www.medscape.org/viewarticle/758910_print As an organization accredited by the ACCME, Medscape, LLC, requires everyone who is in a position to control thecontent of an education activity to disclose al relevant financial relationships with any commercial interest. TheACCME defines "relevant financial relationships" as financial relationships in any amount, occurring within the past12 months, including financial relationships of a spouse or life partner, that could create a conflict of interest.
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Author(s)
Fran Lowry
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Brande Nicole Martin, MA
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CME Author(s)
Laurie Barclay, MD
Freelance writer and reviewer, Medscape, LLC Disclosure: Laurie Barclay, MD, has disclosed no relevant financial relationships.
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Sarah Fleischman
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CT/CTA May Predict Risk for Recurrent Stroke CME
News Author: Fran Lowry
CME Author: Laurie Barclay, MD
CME Released: 02/21/2012; Valid for credit through 02/21/2013 After a transient ischemic attack (TIA) or minor stroke, the risk for recurrent stroke within 90 days is approximately CT/CTA May Predict Risk for Recurrent Stroke (printer-friendly) http://www.medscape.org/viewarticle/758910_print 10%. Most of these recurrent strokes occur within 48 hours of the TIA, indicating a need to identify the highest-riskpatients as soon as possible to begin early interventions.
Magnetic resonance imaging (MRI) can identify patients at high risk for a recurrent stroke, but it is often notavailable as an emergency procedure. If computed tomography (CT)/CT angiography (CTA) imaging is similarlyclinical y predictive, this strategy would be more widely applicable. The objectives of this study by Coutts andcol eagues were to determine whether CT/CTA could predict recurrent stroke in patients with TIA and minor stroke,and to compare the prediction of recurrent stroke with use of CT/CTA vs that of MRI diffusion-weighted imaging(DWI).
In centers that lack ready access to MRI, using CT/CTA to assess the intra- and extracranial vasculature soon aftera patient suffers a TIA or minor stroke is a viable way to predict risk for a future, more serious stroke, according tonew research.
"In many institutions, CTA is more readily available than MRI and physicians should access whichever technique ismore quickly available," Shelagh B. Coutts, MD, from the University of Calgary in Alberta, Canada, told MedscapeMedical News.
"CT/CTA can be used to triage patients with TIA and minor stroke," she said. "Patients with normal imaging can gohome. Others would need to be treated more aggressively, admitted to hospital, and so on. CT/CTA is as good atthis as MRI, which most patients don’t have access to. However, many emergency rooms have access to CT/CTA." The addition of CTA, which uses intravenous contrast media to assess the intracranial and extracranial vasculature,adds less than 5 minutes to a standard brain CT and can be safely completed in most patients, Dr. Coutts said.
The results from the prospective Canadian Assessment of Tomography for Childhood Head injury (CATCH) studywere presented here at the International Stroke Conference (ISC) 2012 and published simultaneously online in theFebruary 1 issue of Stroke.
Independent Predictor
An intracranial arterial occlusion identified by CTA is an independent predictor of poor outcome in patients withacute stroke and TIA. Also, large artery disease is readily identifiable on CTA and is the stroke mechanism with thehighest risk for early stroke recurrence.
In the current study, 510 patients with TIA and minor stroke underwent CT of the brain and CTA of the circle of Wil isand neck within 24 hours of symptom onset, and then had an MRI. Their median age was 69 years (range, 27 - 99years).
The 90-day risk for recurrent stroke was assessed using standard clinical variables, including the age, bloodpressure, clinical features, duration, diabetes (ABCD2) score. In addition, patients whose CT scans showed acuteischemia, or whose CT/CTA scans showed intracranial or extracranial vessel occlusion or stenosis of 50% or moreipsilateral to the ischemic brain tissue, were defined as being at high risk for future stroke, as were patients whowere DWI positive on MRI.
There were 36 recurrent strokes (7.1%; 95% confidence interval [CI], 5.0% - 9.6%), which occurred a median of 1day (interquartile range [IQR], 7.5 days) after the first TIA.
Delays With MRI
The median time to CTA from symptom onset was 5.5 hours (IQR, 6.4 hours), whereas the time to MRI was CT/CTA May Predict Risk for Recurrent Stroke (printer-friendly) http://www.medscape.org/viewarticle/758910_print considerably longer, at 17.5 hours (IQR, 12 hours).
Predictors of recurrent stroke were symptoms that were ongoing when patients were first assessed (hazard ratio[HR], 2.2; 95% CI, 1.02 - 4.9), CT/CTA abnormalities (HR, 4.0; 95% CI, 2.0 - 8.5), and DWI-positivity (HR, 2.2; 95%CI, 1.05 - 4.7). However, in the multivariable analysis, only CT/CTA abnormalities predicted recurrent stroke.
The study showed that CT/CTA and DWI MRI were not significantly different in predicting recurrent stroke. ForCT/CTA, the sensitivity was 67%, the specificity was 68%, the positive predictive value (PPV) was 14%, and thenegative predictive value (NPV) was 96%.
For DWI MRI, the sensitivity was 75%, the specificity was 43%, the PPV was 9%, and the NPV was 96%.
The discriminative value in predicting recurrent stroke for CT/CTA was 0.67 (95% CI, 0.59 - 0.76) and for MRI, itwas 0.59 (95% CI, 0.52 - 0.67; P = .09).
Based on these results, Dr. Coutts and her group feel that using CT/CTA has the potential to benefit many peopleworldwide.
"We are trying to change the guidelines so that CTA is the standard of care for patients with high-risk TIA and minorstroke," she said.
Different Paradigms
Medscape Medical News invited Jose Bil er, MD, chairman of neurology at Loyola University Stritch School ofMedicine, Chicago, Il inois, and a spokesperson for the American Academy of Neurology, to comment on this study.
Dr. Bil er said he found it "intriguing" that the investigators were able to obtain CT/CTA much faster than an MRI attheir institution. "That appears to be the reality in Canada, but it may not necessarily apply to hospitals in the US,"he noted. "Everybody has different paradigms in evaluating these patients." What CT/CTA does not reveal is the morphology of the plaque. This would be important to know, he said.
"I think this is a very wel -conducted study, but one caveat I have is that some 15% of their patients had diabetes,"he noted. "We don’t know how many of these patients were getting oral antidiabetic agents like metformin. We try toavoid the administration of iodine contrast in those patients because of the risk of lactic acidosis.
"It would also be important to know their race and ethnicity because we know that African Americans have moreintracranial than extracranial disease, and the same is true among Asians, but we lack that data," he said.
The risk of radiation is another factor that should not be ignored, "especial y if you are planning repeat studies," Dr.
Bil er said.
"When the risk of stroke in the early hours of a TIA can be quantified by the ABCD2 score I think that the real way oflooking at these patients wil be to supplement the ABCD2 score with other characteristics that come from imaging,whatever paradigm you want to use," he added. Options would include CT/CTA, MRI, magnetic resonanceangiography, or even ultrasound with the addition of biomarkers of ongoing inflammation such as C-reactive protein.
The study was supported by the Canadian Institute of Health Research (CIHR) and a Pfizer Cardiovascularresearch award. Dr. Coutts has received salary support from the Alberta-Innovates-Health solutions and the Heartand Stroke Foundation of Canada’s Distinguished Clinician Scientist award supported in partnership with the CIHR,Institute of Circulatory and Respiratory Health, and AstraZeneca Canada, Inc. Dr. Bil er is a spokesperson for the CT/CTA May Predict Risk for Recurrent Stroke (printer-friendly) http://www.medscape.org/viewarticle/758910_print International Stroke Conference (ISC) 2012: Abstract 2282. Presented February 1, 2012.
Stroke. Published online February 1, 2012. Abstract The study sample consisted of 510 consecutive patients with TIA or minor stroke who underwent CT/CTAand subsequent MRI.
The enrol ment criterion for TIA events was motor or speech symptoms and not isolated sensory symptoms.
The investigators determined the risk for recurrent stroke within 90 days using standard clinical variables andpredefined imaging abnormalities.
For the CT/CTA, these abnormalities were acute ischemia on CT and/or intracranial or extracranial occlusionor stenosis of at least 50%.
Abnormal MRI results were defined as DWI positivity.
Recurrent stroke occurred in 36 patients (7.1%; 95% CI, 5.0 - 9.6).
Median time to the event was 1 day (IQR, 7.5).
From symptom onset to CTA, median time was 5.5 hours (IQR, 6.4 hours); for MRI, it was 17.5 hours (IQR,12 hours).
Factors predicting recurrent stroke were ongoing symptoms at first assessment (HR, 2.2; 95% CI, 1.02 - 4.9),CT/CTA abnormalities (HR, 4.0; 95% CI, 2.0 - 8.5), and DWI positivity (HR, 2.2; 95% CI, 1.05 - 4.7).
However, only CT/CTA abnormalities predicted recurrent stroke in the multivariable analysis.
Extracranial carotid disease was not a major predictor of recurrent stroke, which the investigators suggestwas because of early definitive treatment.
CT/CTA and MRI did not differ significantly in their discriminative value in predicting recurrent stroke, basedon a secondary analysis (0.67; 95% CI, 0.59 - 0.76 vs 0.59; 95% CI, 0.52 - 0.67; P = .09).
On the basis of these findings, the investigators concluded that early assessment of the intracranial andextracranial vasculature using CT/CTA predicts recurrent stroke and clinical outcome in patients withtransient ischemic attack and minor stroke.
The investigators also noted that CTA is more readily available than MRI in many institutions and thatclinicians should use whichever technique is more quickly available at their institution.
Limitations of this study include inability to extrapolate the findings to transient sensory events andimputation of the DWI MRI result.
In patients with TIA or minor stroke, early assessment of the intracranial and extracranial vasculature usingCT/CTA predicts recurrent stroke and clinical outcome, based on a prospective study.
CT/CTA and MRI were similar in their ability to predict recurrent stroke. The investigators suggest that CTA ismore readily available than MRI in many institutions and that clinicians use whichever technique is morequickly available at their institution.
To receive AMA PRA Category 1 Credit™, you must receive a minimum score of 70% on the post-test.
According to the prospective CATCH study by Coutts and col eagues, which of the fol owingstatements about the ability of CT/CTA to predict recurrent stroke in patients with TIA and minorstroke is not correct? On univariate analysis, the HR for recurrent stroke was 4.0 for CT/CTA abnormalitiesOnly CT/CTA abnormalities predicted recurrent stroke in multivariable analysisCT/CTA abnormalities were defined as acute ischemia on CT and/or intracranial or CT/CTA May Predict Risk for Recurrent Stroke (printer-friendly) http://www.medscape.org/viewarticle/758910_print extracranial occlusion or stenosis of at least 50% Extracranial carotid disease was a major predictor of recurrent stroke Your patient is a 68-year-old white man presenting to the emergency room with motor symptomssuggesting TIA. According to the prospective CATCH study by Coutts and col eagues, which of thefol owing statements about using CT/CTA or MRI DWI to predict recurrent stroke is most likelycorrect? Emergency MRI is more readily available than emergency CT/CTA in most institutionsCT/CTA is significantly better than MRI in predicting recurrent strokeMRI is significantly better than CT/CTA in predicting recurrent strokeClinicians should use whichever technique is more quickly available at their institution This article is a CME certified activity. To earn credit for this activity visit:
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