Cost Effectiveness of Interhospital Transfer for Mechanical Thrombectomy of Acute Large Vessel Occlusion Stroke: Role of Predicted Recanalization Rates.

BACKGROUND: Emergency interhospital transfer of patients with stroke with large vessel occlusion to a comprehensive stroke center for mechanical thrombectomy is resource-intensive and can be logistically challenging. Imaging markers may identify patients in whom intravenous thrombolysis (IVT) alone is likely to result in thrombus resolution, potentially rendering interhospital transfers unnecessary. Here, we investigate how predicted probabilities to achieve IVT-mediated recanalization affect cost-effectiveness estimates of interhospital transfer. METHODS: We performed a health economic analysis comparing emergency interhospital transfer of patients with acute large vessel occlusion stroke after administration of IVT with a scenario in which patients also receive IVT but remain at the primary hospital. Results were stratified by clinical parameters, treatment delays, and the predicted probability to achieve IVT-mediated recanalization. Estimated 3-month outcomes were combined with a long-term probabilistic model to yield quality-adjusted life years (QALYs) and costs. Uncertainty was quantified in probabilistic sensitivity analyses. RESULTS: Depending on input parameters, marginal costs of interhospital transfer ranged from USD -61 366 (cost saving) to USD +20 443 and additional QALYs gained from 0.1 to 3.0, yielding incremental cost-effectiveness ratios of

Assessment of thrombus length in acute ischemic stroke by post-contrast magnetic resonance angiography.

OBJECTIVES: Post-contrast magnetic resonance angiography (PC-MRA) enables visualization of vessel segments distal to an intra-arterial thrombus in acute ischemic stroke. We hypothesized that PC-MRA also allows clot length measurement in different intracranial vessels. METHODS: Patients with MRI-confirmed ischemic stroke and intracranial artery occlusion within 24 hours of symptom onset were prospectively evaluated. PC-MRA was added to a standard stroke MRI protocol. Thrombus length was measured on thick slab maximum intensity projection images. Clinical outcome at hospital discharge was assessed by modified Rankin Scale (mRS). RESULTS: Thirty-four patients (median age 72 years) presenting with a median National Institutes of Health Stroke Scale score of 11 and a median onset to imaging time of 116 min were included. PC-MRA enabled precise depiction of proximal and distal terminus of the thrombus in 31 patients (91%), whereas in three patients (9%) PC-MRA presented a partial occlusion. Median thrombus length in patients with complete occlusion was 9.9 mm. In patients with poor outcome (mRS ≥3) median thrombus length was significantly longer than in those with good outcome (mRS ≤2;P=0.011). CONCLUSIONS: PC-MRA demonstrates intra-arterial thrombus length at different vessel occlusion sites. Longer thrombus length is associated with poor clinical outcome. CLINICAL TRIAL REGISTRATION: NCT02077582; Results.

How does sex affect the care dependency risk one year after stroke? A study based on claims data from a German health insurance fund.

OBJECTIVES: The study explores the association between sex and care dependency risk one year after stroke. METHODS: The study uses claims data from a German statutory health insurance fund. Patients were included if they received a diagnosis of ischemic or hemorrhagic stroke between 1 January and 31 December 2007 and if they survived for one year after stroke and were not dependent on care before the event (n = 1851). Data were collected over a one-year period. Care dependency was defined as needing substantial assistance in activities of daily living for a period of at least six months. Geriatric conditions covered ICD-10 symptom complexes that characterize geriatric patients (e.g. urinary incontinence, cognitive deficits, depression). Multivariate regression analyses were performed. RESULTS: One year after the stroke event, women required nursing care significantly more often than men (31.2% vs. 21.3%; odds ratio for need of assistance: 1.67; 95% CI: 1.36-2.07). Adjusted for age, the odds ratio decreased by 65.7% to 1.23 (n.s.). Adjusted for geriatric conditions, the odds ratio decreased further and did not remain significant (adjusted OR: 1.18 (CI: 0.90-1.53). DISCUSSION: It may be assumed that women have a higher risk of becoming care-dependent after stroke than men because they are older and suffer more often from geriatric conditions such as urinary incontinence at onset of stroke. Preventive strategies should therefore focus on geriatric conditions in order to reduce the post-stroke care dependency risk for women.

Stroke and myocardial infarction: a comparative systematic evaluation of gender-specific analysis, funding and authorship patterns in cardiovascular research.

BACKGROUND: Major gender differences exist in cardiovascular diseases and lead to different outcomes in women and men. However, attention and incorporation of sex-/gender-specific research might vary among disciplines. We therefore conducted a systematic review comparing publication characteristics and trends between stroke and myocardial infarction (MI) with respect to sex- and gender-related aspects. METHODS: A systematic literature search was performed in PubMed to identify gender-/sex-related articles published for stroke and MI between 1977 and 2008. A specifically designed text mining program was used, and all literature was rated by two independent investigators. Publications were classified according to type of research performed, publication year, funding, geographical location, and gender of first and last authors. RESULTS: 962 articles were retrieved and limited to 405 (42%) gender-relevant publications; 131 on stroke and 274 on MI. Type of performed research differed, especially in disease management, which received little attention (17%) in stroke, while representing the major focus in MI (40%). In both areas, clinical presentation received little attention (3 and 5%). Although publications progressively increased in both fields, an 8- to 10-year time gap emerged for stroke compared to MI. Last authors in both areas were predominantly men, but female last authorship is increasing more significantly over time in the field of stroke. Research on sex and gender differences in MI and stroke is largely underfunded, particularly by the EU. CONCLUSIONS: The data demonstrate how sex-/gender-specific research differs between specialties, most likely due to the diverse interest, funding opportunities and authorship distributions identified.

Correcting saturation effects of the arterial input function in dynamic susceptibility contrast-enhanced MRI: a Monte Carlo simulation.

To prevent systematic errors in quantitative brain perfusion studies using dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI), a reliable determination of the arterial input function (AIF) is essential. We propose a novel algorithm for correcting distortions of the AIF caused by saturation of the peak amplitude and discuss its relevance for longitudinal studies. The algorithm is based on the assumption that the AIF can be separated into a reliable part at low contrast agent concentrations and an unreliable part at high concentrations. This unreliable part is reconstructed, applying a theoretical framework based on a transport-diffusion theory and using the bolus-shape in the tissue. A validation of the correction scheme is tested by a Monte Carlo simulation. The input of the simulation was a wide range of perfusion, and the main aim was to compare this input to the determined perfusion parameters. Another input of the simulation was an AIF template derived from in vivo measurements. The distortions of this template was modeled via a Rician distribution for image intensities. As for a real DSC-MRI experiment, the simulation returned the AIF and the tracer concentration-dependent signal in the tissue. The novel correction scheme was tested by deriving perfusion parameters from the simulated data for the corrected and the uncorrected case. For this analysis, a common truncated singular value decomposition approach was applied. We find that the saturation effect caused by Rician-distributed noise leads to an overestimation of regional cerebral blood flow and regional cerebral blood volume, as compared to the input parameter. The aberration can be amplified by a decreasing signal-to-noise ratio (SNR) or an increasing tracer concentration. We also find that the overestimation can be successfully eliminated by the proposed saturation-correction scheme. In summary, the correction scheme will allow DSC-MRI to be expanded towards higher tracer concentrations and lower SNR and will help to increase the measurement to measurement reproducibility for longitudinal studies.

The impact of atrial fibrillation on the cost of stroke: the berlin acute stroke study.

OBJECTIVES: Atrial fibrillation (AF) is an important risk factor for stroke. The primary purpose of this study was to determine the resource use for patients admitted to hospital with acute stroke and to calculate stroke-related direct costs, stratifying the results according to the presence of AF as a risk factor. METHODS: Data from 558 consecutive patients hospitalized with confirmed acute stroke between August 2000 and July 2001 were analyzed as part of the Berlin Acute Stroke Study. Sociodemographic variables were assessed by direct interview, while hospital data were derived from patient medical records. Patients or their carers completed a follow-up questionnaire about resource utilization and absenteeism from work during the 12-month period after hospital admission. RESULTS: Out of the 367 patients with follow-up data and ECG findings, 71 (19%) had AF. Patients with AF were generally older, more likely to be female, and had more severe strokes compared with those without AF. Mean direct costs per patient were significantly higher in those with AF-related strokes (EURO 11,799 vs EURO 8817 for non-AF-related strokes; P < 0.001). After adjustment for confounding factors, direct costs were comparable in the two groups, except for acute hospitalization costs, which remained significantly higher in the group with AF (P < 0.05). CONCLUSION: Medical care for stroke patients with AF is associated with higher costs compared with those without AF; this is explained mainly by confounding factors and driven essentially by a significant difference in acute hospitalization costs.

The use of the 12-item short-form health status instrument in a longitudinal study of patients with stroke and transient ischaemic attack.

The 36-item short-form health survey (SF-36) is one of the most commonly used health status instruments in patients with cerebrovascular disease. However, responsiveness to change in health-related quality of life (HRQoL) has not yet been assessed for the SF-36 and its shortened version, the SF-12. The main objective of the present study was to determine responsiveness to change of the SF-12 in patients with cerebrovascular disease. Patients with stroke/transient ischaemic attack (TIA) were included at admission to one of four participating hospitals. HRQoL was assessed with the Physical (PCS-12) and Mental (MCS-12) Component Summary scales at baseline (referring to the status prior to the event) and after 12 months. Responsiveness to change was determined with the standardized response mean (SRM) and classified as small (SRM 0.20-0.49), moderate (0.50-0.79) or large (> or =0.80). A total of 558 patients were included [55% men, mean age 65 (SD, 13) years; 45% women, mean age 69 (SD, 14) years]. Indications for admission were stroke (74%) and TIA (26%). In patients with stroke, SRMs were small for the PCS-12 [SRM 0.49; absolute change -5.9 (SD, 12)] and moderate for the MCS-12 [SRM 0.52; absolute change -6.6 (SD, 13)]. In patients with TIA, SRMs were below 0.2 for the PCS-12 [absolute change -0.7 (SD, 11)] and small for the MCS-12 [SRM 0.34; absolute change -3.7 (SD, 11)]. SRMs increased with stroke severity as indicated by the NIHSS score. The SF-12 summary scales showed a small to moderate responsiveness to change in patients after stroke. Responsiveness to change was higher in patients with increased symptom severity.