Anthony S. Kim

Global Variation in the Relative Burden of Stroke and Ischemic Heart Disease

Background— Although stroke and ischemic heart disease (IHD) have several well-established risk factors in common, the extent of global variation in the relative burdens of these forms of vascular disease and reasons for any observed variation are poorly understood. Methods and Results— We analyzed mortality and disability-adjusted life-year loss rates from stroke and IHD, as well as national estimates of vascular risk factors that have been developed by the World Health Organization Burden of Disease Program. National income data were derived from World Bank estimates. We used linear regression for univariable analysis and the Cuzick test for trends. Among 192 World Health Organization member countries, stroke mortality rates exceeded IHD rates in 74 countries (39%), and stroke disability-adjusted life-year loss rates exceeded IHD rates in 62 countries (32%). Stroke mortality ranged from 12.7% higher to 27.2% lower than IHD, and stroke disability-adjusted life-year loss rates ranged from 6.2% higher to 10.2% lower than IHD. Stroke burden was disproportionately higher in China, Africa, and South America, whereas IHD burden was higher in the Middle East, North America, Australia, and much of Europe. Lower national income was associated with higher relative mortality (P<0.001) and burden of disease (P=0.001) from stroke. Diabetes mellitus prevalence and mean serum cholesterol were each associated with greater relative burdens from IHD even after adjustment for national income. Conclusions— There is substantial global variation in the relative burden of stroke compared with IHD. The disproportionate burden from stroke for many lower-income countries suggests that distinct interventions may be required.

Addition of Brain Infarction to the ABCD2 Score (ABCD2I) A Collaborative Analysis of Unpublished Data on 4574 Patients

Background and Purpose— The ABCD system was developed to predict early stroke risk after transient ischemic attack. Incorporation of brain imaging findings has been suggested, but reports have used inconsistent methods and been underpowered. We therefore performed an international, multicenter collaborative study of the prognostic performance of the ABCD2 score and brain infarction on imaging to determine the optimal weighting of infarction in the score (ABCD2I). Methods— Twelve centers provided unpublished data on ABCD2 scores, presence of brain infarction on either diffusion-weighted imaging or CT, and follow-up in cohorts of patients with transient ischemic attack diagnosed by World Health Organization criteria. Optimal weighting of infarction in the ABCD2I score was determined using area under the receiver operating characteristic curve analyses and random effects meta-analysis. Results— Among 4574 patients with TIA, acute infarction was present in 884 (27.6%) of 3206 imaged with diffusion-weighted imaging and new or old infarction was present in 327 (23.9%) of 1368 imaged with CT. ABCD2 score and presence of infarction on diffusion-weighted imaging or CT were both independently predictive of stroke (n=145) at 7 days (after adjustment for ABCD2 score, OR for infarction=6.2, 95% CI=4.2 to 9.0, overall; 14.9, 7.4 to 30.2, for diffusion-weighted imaging; 4.2, 2.6 to 6.9, for CT; all P<0.001). Incorporation of infarction in the ABCD2I score improved predictive power with an optimal weighting of 3 points for infarction on CT or diffusion-weighted imaging. Pooled areas under the curve increased from 0.66 (0.53 to 0.78) for the ABCD2 score to 0.78 (0.72 to 0.85) for the ABCD2I score. Conclusions— In secondary care, incorporation of brain infarction into the ABCD system (ABCD2I score) improves prediction of stroke in the acute phase after transient ischemic attack.

Pax-6 regulates expression of SFRP-2 and Wnt-7b in the developing CNS.

Wnt signaling regulates a wide range of developmental processes such as proliferation, cell migration, axon guidance, and cell fate determination. In this report, we studied the expression of secreted frizzled related protein-2 (SFRP-2), which codes for a putative Wnt inhibitor, in the developing nervous system. SFRP-2 is expressed in several discrete neuroepithelial domains, including the diencephalon, the insertion of the eminentia thalami into the caudal telencephalon, and the pallial-subpallial boundary (PSB). We also noted that Wnt-7b expression was similar to SFRP-2 expression. Because many of these structures are disrupted in Pax-6 mutant mice, we examined SFRP-2 and Wnt-7b expression in the forebrains of Pax-6 Sey/Sey mice. We found that Pax-6 mutants lack SFRP-2 expression in the PSB and diencephalon. Interestingly, Pax-6 mutants also lack Wnt-7b expression in the PSB, but Wnt-7b expression in the diencephalon is preserved. Furthermore, in the spinal cord of Pax-6 mutants, SFRP-2 and Wnt-7b expression was greatly reduced. Our results suggest that by virtue of its apposition to Wnt-7b expression, SFRP-2 may modulate its function, particularly at boundaries such as the PSB, and that changes in Wnt signaling contribute to the phenotype of Pax-6 mutants.

Clinical Outcomes of Transplanted Modified Bone Marrow–Derived Mesenchymal Stem Cells in Stroke: A Phase 1/2a Study

Background and Purpose— Preclinical data suggest that cell-based therapies have the potential to improve stroke outcomes. Methods— Eighteen patients with stable, chronic stroke were enrolled in a 2-year, open-label, single-arm study to evaluate the safety and clinical outcomes of surgical transplantation of modified bone marrow–derived mesenchymal stem cells (SB623). Results— All patients in the safety population (N=18) experienced at least 1 treatment-emergent adverse event. Six patients experienced 6 serious treatment-emergent adverse events; 2 were probably or definitely related to surgical procedure; none were related to cell treatment. All serious treatment-emergent adverse events resolved without sequelae. There were no dose-limiting toxicities or deaths. Sixteen patients completed 12 months of follow-up at the time of this analysis. Significant improvement from baseline (mean) was reported for: (1) European Stroke Scale: mean increase 6.88 (95% confidence interval, 3.5–10.3; P<0.001), (2) National Institutes of Health Stroke Scale: mean decrease 2.00 (95% confidence interval, −2.7 to −1.3; P<0.001), (3) Fugl-Meyer total score: mean increase 19.20 (95% confidence interval, 11.4–27.0; P<0.001), and (4) Fugl-Meyer motor function total score: mean increase 11.40 (95% confidence interval, 4.6–18.2; P<0.001). No changes were observed in modified Rankin Scale. The area of magnetic resonance T2 fluid-attenuated inversion recovery signal change in the ipsilateral cortex 1 week after implantation significantly correlated with clinical improvement at 12 months (P<0.001 for European Stroke Scale). Conclusions— In this interim report, SB623 cells were safe and associated with improvement in clinical outcome end points at 12 months. Clinical Trial Registration— URL: https://www.clinicaltrials.gov. Unique identifier: NCT01287936.

Early stroke risk and ABCD2 score performance in tissue- vs time-defined TIA A multicenter study

Objectives: Stroke risk immediately after TIA defined by time-based criteria is high, and prognostic scores (ABCD2 and ABCD3-I) have been developed to assist management. The American Stroke Association has proposed changing the criteria for the distinction between TIA and stroke from time-based to tissue-based. Research using these definitions is lacking. In a multicenter observational cohort study, we have investigated prognosis and performance of the ABCD2 score in TIA, subcategorized as tissue-positive or tissue-negative on diffusion-weighted imaging (DWI) or CT imaging according to the newly proposed criteria. Methods: Twelve centers provided data on ABCD2 scores, DWI or CT brain imaging, and follow-up in cohorts of patients with TIA diagnosed by time-based criteria. Stroke rates at 7 and 90 days were studied in relation to tissue-positive or tissue-negative subcategorization, according to the presence or absence of brain infarction. The predictive power of the ABCD2 score was determined using area under receiver operator characteristic curve (AUC) analyses. Results: A total of 4,574 patients were included. Among DWI patients (n = 3,206), recurrent stroke rates at 7 days were 7.1%(95% confidence interval 5.5–9.1) after tissue-positive and 0.4% (0.2–0.7) after tissue-negative events (p diff < 0.0001). Corresponding rates in CT-imaged patients were 12.8% (9.3–17.4) and 3.0% (2.0–4.2), respectively (p diff < 0.0001). The ABCD2 score had predictive value in tissue-positive and tissue-negative events (AUC = 0.68 [95% confidence interval 0.63–0.73] and 0.73 [0.67–0.80], respectively; p sig < 0.0001 for both results, p diff = 0.17). Tissue-positive events with low ABCD2 scores and tissue-negative events with high ABCD2 scores had similar stroke risks, especially after a 90-day follow-up. Conclusions: Our findings support the concept of a tissue-based definition of TIA and stroke, at least on prognostic grounds.

Wnt receptors and Wnt inhibitors are expressed in gradients in the developing telencephalon.

The caudomedial margin of the medial pallium, known as the cortical hem, expresses several Wnt genes that have been shown to be crucial for cortical development. We examined the expression of members of the Frizzled (mFz) family of Wnt receptors and the Secreted Frizzled Related Protein (SFRP) family of Wnt inhibitors during telencephalic development. We found that mFz-5 and mFz-8 are specifically expressed in the neocortical neuroepithelium and excluded from the hippocampal neuroepithelium in early telencephalic development, whereas mFz-9 and mFz-10 have expression domains confined to the medial pallium. In addition, SFRP-1 and SFRP-3 are expressed in opposing anterolateral to caudomedial gradients within the telencephalic ventricular zone throughout corticogenesis.

Cost-Effectiveness of Dabigatran Compared With Warfarin for Stroke Prevention in Patients With Atrial Fibrillation and Prior Stroke or Transient Ischemic Attack

Background and Purpose— The cost-effectiveness of dabigatran for stroke prevention in patients with atrial fibrillation and prior stroke or transient ischemic attack has not been directly assessed. Methods— A Markov decision model was constructed using data from the Randomized Evaluation of Long-Term Therapy (RE-LY) trial, other trials of warfarin therapy for atrial fibrillation, and the published cost of dabigatran. We compared the cost and quality-adjusted life expectancy associated with 150 mg dabigatran twice daily versus warfarin therapy targeted to an international normalized ratio of 2 to 3. The target population was a cohort of patients aged ≥70 years with nonvalvular atrial fibrillation, prior stroke or transient ischemic attack, and no contraindication to anticoagulation. Results— In the base case, dabigatran was associated with 4.27 quality-adjusted life-years compared with 3.91 quality-adjusted life-years with warfarin. Dabigatran provided 0.36 additional quality-adjusted life-years at a cost of

Cost-effectiveness of apixaban vs warfarin for secondary stroke prevention in atrial fibrillation

9000, yielding an incremental cost-effectiveness ratio of

Application of the ABCD2 Score to Identify Cerebrovascular Causes of Dizziness in the Emergency Department

25 000. In sensitivity analyses, the cost-effectiveness of dabigatran was inversely related to the quality of international normalized ratio control achieved with warfarin therapy. In Monte Carlo analysis, dabigatran was cost-effective in 57% of simulations using a threshold of

Risk of Vascular Events in Emergency Department Patients Discharged Home With Diagnosis of Dizziness or Vertigo

50 000 per quality-adjusted life-year and 78% of simulations using a threshold of