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Full Title: Effectiveness and Cost-Effectiveness of Echocardiography and Carotid Imaging in the Management of Stroke
View or download Summary/Report
Objectives: Considerable controversy exists over the appropriate use of imaging procedures to target stroke treatments, such as carotid endarterectomy (CEA) and anticoagulant therapy, to those most likely to benefit. This report discusses the effectiveness and cost-effectiveness of various imaging strategies for evaluating and managing new stroke patients: transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), carotid ultrasound (CUS), magnetic resonance imaging (MRA), and cerebral angiography.
Search Strategy: Literature databases searched included MEDLINE®, HealthSTAR, the Cochrane Controlled Trials Register, the Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effectiveness, and Health Technology Assessment.
Selection Criteria: Two investigators independently reviewed the retrieved abstracts for each key question using predetermined inclusion/exclusion criteria, then compared results. Differences were resolved through discussions between the reviewers. Specific exclusion criteria were applied to individual key questions.
Data Collection and Analysis: A review of 4,159 potentially relevant citations yielded 210 articles meeting eligibility criteria. Evidence tables summarize study quality and abstracted data, and where appropriate, results are synthesized by meta-analysis. Cost-effectiveness analyses are in the form of decision analyses.
Results and Conclusions:
- Echocardiography: Available evidence is insufficient to allow conclusions regarding whether and to what degree most echocardiographically identifiable lesions are associated with increased risk of future stroke. Moreover, insufficient data exist regarding the efficacy of treatment for reducing the risk of future stroke associated with intracardiac thrombus or other lesions identifiable with echocardiography. Under current estimates of echocardiographic accuracy and the prevalence of intracardiac thrombus, testing all stroke patients with echocardiography likely results in false positives at least as often as true positives. Assuming that anticoagulation reduces the risk of recurrent stroke from intracardiac thrombus by 33 percent over one year, both TEE and TTE cost over $290,000 per quality-adjusted life year (QALY) saved at thrombus prevalences of 5 percent or below. Cost-effectiveness ratios dropped below $50,000 per QALY if the relative risk reduction with anticoagulation was 86 percent and the prevalence of thrombus at least 6 percent. More information is needed on the risk of recurrent stroke among those with potential sources of cardioembolism, and the efficacy of anticoagulation in reducing that risk.
- Carotid Imaging: The accuracy of CUS appears to vary substantially across centers. MRA may be more accurate than CUS, but few high-quality studies have addressed its accuracy. The combination of CUS and MRA has high reported sensitivity, but all relevant studies to date have been affected by verification bias and were of fair to poor methodological quality. In cost-effectiveness analyses varying sensitivities and specificities of noninvasive tests over a wide range, all testing strategies cost at least $250,000 per QALY when the prevalence of severe (70-99 percent) stenosis was assumed to be 15 percent. However, two testing strategies—initial CUS with angiographic confirmation and CEA for those with severe stenosis, and MRA with direct referral to CEA for those with severe stenosis—had cost-effectiveness ratios below $75,000 per QALY when the prevalence of severe stenosis increased above 20 percent, and below $50,000 per QALY as the prevalence exceeded 25-30 percent. High-quality assessments of CUS, MRA, and cerebral angiography are needed to better inform clinical decisionmaking about the appropriate use of these imaging strategies.
Effectiveness and Cost-Effectiveness of Echocardiography and Carotid Imaging in the Management of Stroke
Evidence-based Practice Center: Oregon Health & Science University
Topic Nominator: American Academy of Neurology
Current as of July 2002