An assessment of the cost-effectiveness of magnetic resonance, including diffusion-weighted imaging, in patients with transient ischaemic attack and minor stroke: a systematic review, meta-analysis and economic evaluation

Abstract

BackgroundPatients with transient ischaemic attack (TIA) or minor stroke need rapid treatment of risk factors to prevent recurrent stroke. ABCD2 score or magnetic resonance diffusion-weighted brain imaging (MR DWI) may help assessment and treatment.ObjectivesIs MR with DWI cost-effective in stroke prevention compared with computed tomography (CT) brain scanning in all patients, in specific subgroups or as ‘one-stop’ brain-carotid imaging? What is the current UK availability of services for stroke prevention?Data sourcesPublished literature; stroke registries, audit and randomised clinical trials; national databases; survey of UK clinical and imaging services for stroke; expert opinion.Review methodsSystematic reviews and meta-analyses of published/unpublished data. Decision-analytic model of stroke prevention including on a 20-year time horizon including nine representative imaging scenarios.ResultsThe pooled recurrent stroke rate after TIA (53 studies, 30,558 patients) is 5.2% [95% confidence interval (CI) 3.9% to 5.9%] by 7 days, and 6.7% (5.2% to 8.7%) at 90 days. ABCD2 score does not identify patients with key stroke causes or identify mimics: 66% of specialist-diagnosed true TIAs and 35–41% of mimics had an ABCD2 score of ≥ 4; 20% of true TIAs with ABCD2 score of < 4 had key risk factors. MR DWI (45 studies, 9078 patients) showed an acute ischaemic lesion in 34.3% (95% CI 30.5% to 38.4%) of TIA, 69% of minor stroke patients, i.e. two-thirds of TIA patients are DWI negative. TIA mimics (16 studies, 14,542 patients) make up 40–45% of patients attending clinics. UK survey (45% response) showed most secondary prevention started prior to clinic, 85% of primary brain imaging was same-day CT; 51–54% of patients had MR, mostly additional to CT, on average 1 week later; 55% omitted blood-sensitive MR sequences. Compared with ‘CT scan all patients’ MR was more expensive and no more cost-effective, except for patients presenting at > 1 week after symptoms to diagnose haemorrhage; strategies that triaged patients with low ABCD2 scores for slow investigation or treated DWI-negative patients as non-TIA/minor stroke prevented fewer strokes and increased costs. ‘One-stop’ CT/MR angiographic-plus-brain imaging was not cost-effective.LimitationsData on sensitivity/specificity of MR in TIA/minor stroke, stroke costs, prognosis of TIA mimics and accuracy of ABCD2 score by non-specialists are sparse or absent; all analysis had substantial heterogeneity.ConclusionsMagnetic resonance with DWI is not cost-effective for secondary stroke prevention. MR was most helpful in patients presenting at > 1 week after symptoms if blood-sensitive sequences were used. ABCD2 score is unlikely to facilitate patient triage by non-stroke specialists. Rapid specialist assessment, CT brain scanning and identification of serious underlying stroke causes is the most cost-effective stroke prevention strategy.FundingThe National Institute for Health Research Health Technology Assessment programme.

Long-Term Effect of Participation in an Early Exercise and Education Program on Clinical Outcomes and Cost Implications, in Patients with TIA and Minor, Non-Disabling Stroke

“…The present study provides preliminary evidence that early exercise and education engagement could significantly reduce the economic burden associated with recurrent vascular events post-stroke/TIA [2]. This study has shown that the costs associated with hospital admissions were 141% higher in the usual care control group compared to those randomized to the exercise and education program.…”

“…Stroke is the second most common cause of death, the primary cause of dependency, creates a huge societal burden and costs billions to the global economy in health and social care costs [1,2]. A transient ischemic attack (TIA) is an ischaemic brain attack with focal cerebral or retinal symptoms that last under 24 hours, usually less than 1 hour [3].…”

“…A transient ischemic attack (TIA) is an ischaemic brain attack with focal cerebral or retinal symptoms that last under 24 hours, usually less than 1 hour [3]. Although patients with minor (non-disabling) stroke differ slightly from those with TIA as signs and symptoms last more than 24 hours, minor stroke patients are assessed and treated similarly to TIA patients to prevent a further disabling stroke, myocardial infarction or death [2,4,5].…”

“…2 The risk of stroke after TIA is between 3-10 % at 2 days, and 9-17 % at 90 days [2,[6][7][8][9], and this is placing an ever increasing burden on health care systems. Longitudinal cohort studies have shown that the risk of cardiovascular events remains high (≤ 44%) 10 years post-TIA or stroke [10,11].…”

Transient ischemic attack: management in the emergency department and impact of an outpatient neurovascular clinic

“…19 This has sparked a shift towards use of a tissue-based definition of TIA. However, timely access to MRI and expert interpretation is not always available, and MRI is not cost-effective compared to CT. 20 It also remains to be seen whether use of plasminogen activator in patients with recent prior clinical symptoms lasting <24 hours associated with small MRI lesions is safe and effective. For these reasons, a tissue-based definition of TIA has yet to be widely endorsed.…”