Articles from Stroke

Link to journal online
Earnshaw, Stephanie R. PhD; Jackson, Dan MSc; Farkouh, Ray PhD; Schwamm, Lee MD;
Cost-Effectiveness of Patient Selection Using Penumbral-Based MRI for Intravenous Thrombolysis.
Stroke. 40(5):1710-1720, May 2009.
Abstract
Background and Purpose-: Better selection of patients for intravenous recombinant tissue plasminogen activator (IV tPA) treatment may improve clinical outcomes. We examined the cost-effectiveness of adding penumbral-based MRI to usual computed tomography (CT)-based methods to identify patients for IV tPA treatment.Methods-: A decision-analytic model estimated the lifetime costs and outcomes associated with penumbral-based MRI selection in a patient population similar to that enrolled in the IV tPA clinical trials. Inputs were obtained from published literature, clinical trial data, claims databases, and expert opinion. Outcomes included cost per life-year saved and cost per quality-adjusted life-year (QALY) gained. Costs and outcomes were discounted at 3% annually. Sensitivity analyses were conducted.Results-: The addition of penumbral-based MRI selection increased total cost by $103 over the patient's remaining lifetime. Penumbral-based MRI selection resulted in favorable outcomes (modified Rankin Scale <=1) more often than CT-based selection (36.66% versus 35.06%) with an incremental cost per life year of $1840 and an incremental cost per QALY of $1004. Multivariate sensitivity analysis predicted cost-effectiveness (<=$50 000 per QALY) in 99.7% of simulation runs.Conclusions-: Selecting ischemic stroke patients for IV tPA treatment using penumbral-based MRI after routine CT may increase overall acute care costs, but the benefit is large enough to make this highly cost-effective. This economic analysis lends further support to the consideration of a paradigm shift in acute stroke evaluation

Kidwell, Chelsea S. MD; Lees, Kennedy R. MD; Muir, Keith W. MD; Chen, Christopher et al
Results of the MRI Substudy of the Intravenous Magnesium Efficacy in Stroke Trial.
Stroke. 40(5):1704-1709, May 2009.
Abstract
Background and Purpose-: Although magnesium is neuroprotective in animal stroke models, no clinical benefit was confirmed in the Intravenous Magnesium Efficacy in Stroke (IMAGES) trial of acute stroke patients. The Magnetic Resonance in IMAGES (MR IMAGES) substudy investigated the effects of magnesium on the imaging surrogate outcome of infarct growth.Methods-: IMAGES trial patients in participating centers were randomized to receive either intravenous magnesium or placebo within 12 hours of stroke onset. Infarct growth was defined as volume difference between baseline diffusion-weighted imaging and day 90 fluid-attenuated inversion recovery image lesions. Patients who died were imputed the largest infarct growth observed.Results-: Among the 90 patients included in the primary analysis, there was no difference in infarct growth (median absolute growth, P=0.639; median percentage growth, P=0.616; proportion with any growth, P=0.212) between the 46 treated with magnesium and 44 with placebo. Infarct growth correlated with NIHSS score change from baseline to day 90. There was a trend showing baseline serum glucose correlated with infarct growth with magnesium treatment, but not in the placebo group. The mismatch frequency was reduced from 73% to 47% by increasing the mismatch threshold from >20% to >100% of core volume.Conclusions-: Infarct growth, confirmed here as a surrogate for clinical progression, was similar between magnesium and placebo treatment, paralleling the main IMAGES trial clinical outcomes. Glucose was a covariate for infarct growth with magnesium treatment. A more stringent mismatch threshold to define penumbra more appropriately would have excluded half of the patients in this 12-hour time window stroke study.

Heiss, Wolf-Dieter MD; Sorensen, A Gregory MD;
Advances in Imaging
Source
Stroke. 40(5):e313-e314, May 2009.