Background and purpose
For patients with acute ischaemic stroke due to large‐vessel occlusion, it has recently been shown that mechanical thrombectomy (MT) with stent retrievers is better than ...medical treatment alone. However, few hospitals can provide MT 24 h/day 365 days/year, and it remains unclear whether selected patients with acute stroke should be directly transferred to the nearest MT‐providing hospital to prevent treatment delays. Clinical scales such as Rapid Arterial Occlusion Evaluation (RACE) have been developed to predict large‐vessel occlusion at a pre‐hospital level, but their predictive value for MT is low. We propose new criteria to identify patients eligible for MT, with higher accuracy.
Methods
The Direct Referral to Endovascular Center criteria were defined based on a retrospective cohort of 317 patients admitted to a stroke center. The association of age, sex, RACE scale score and blood pressure with the likelihood of receiving MT were analyzed. Cut‐off points with the highest association were thereafter evaluated in a prospective cohort of 153 patients from nine stroke units comprising the Madrid Stroke Network.
Results
Patients with a RACE scale score ≥ 5, systolic blood pressure <190 mmHg and age <81 years showed a significantly higher probability of undergoing MT (odds ratio, 33.38; 95% confidence interval, 12–92.9). This outcome was confirmed in the prospective cohort, with 68% sensitivity, 84% specificity, 42% positive and 94% negative predictive values for MT, ruling out 83% of hemorrhagic strokes.
Conclusions
The Direct Referral to Endovascular Center criteria could be useful for identifying patients suitable for MT.
Dementia in hypopituitarism Villarejo, A.; Díaz-Guzman, J.; Bermejo-Pareja, F.
European journal of neurology,
06/2008, Letnik:
15, Številka:
6
Journal Article
Background and purpose
The existence of contraindications to intravenous thrombolysis (IVT) is considered a criterion for direct transfer of patients with suspected acute stroke to ...thrombectomy‐capable centers in the prehospital setting. Our aim was to assess the utility of this criterion in a setting where routing protocols are defined by the Madrid – Direct Referral to Endovascular Center (M‐DIRECT) prehospital scale.
Methods
This was a post hoc analysis of the M‐DIRECT study. Reported contraindications to IVT were retrospectively collected from emergency medical services reports and categorized into late window, anticoagulant treatment and other contraindications. Final diagnosis and treatment rates were compared between patients with and without reported IVT contraindications and according to anticoagulant treatment or late window categories.
Results
The M‐DIRECT study included 541 patients. Reported IVT contraindications were present in 227 (42.0%) patients. Regarding final diagnosis no significant differences were found between patients with or without reported IVT contraindications: ischaemic stroke (any) 65.6% vs. 62.1%, ischaemic stroke with large vessel occlusion (LVO) 32.2% vs. 28.3%, hemorrhagic stroke 15.4% vs. 15.6%, stroke mimic 18.9% vs. 22.3% respectively. Amongst patients with LVO, endovascular thrombectomy (EVT) was performed less often in the presence of IVT contraindications (56.2% vs. 74.2%). M‐DIRECT‐positive patients had higher rates of LVO and EVT compared with M‐DIRECT‐negative patients independent of reported IVT contraindications.
Conclusions
Reported IVT contraindications alone do not increase EVT likelihood and should not be considered to determine routing in urban stroke networks.
Resumen Aproximadamente, 1 de cada 4 ictus isquémicos es de origen cardioembólico. La fibrilación auricular no valvular representa el 50% de estos casos, seguida del infarto de miocardio, los trombos ...intraventriculares, las valvulopatías y una miscelánea de cardiopatías. La incidencia de cardiopatía embólica en la población podría estar en torno a 30 casos por 100.000 habitantes-año, y su prevalencia entre 5–10 casos por 1.000 personas de 65 o más años de edad. La mortalidad intrahospitalaria es elevada, y a los 5 años tan sólo 1 de cada 5 pacientes ha sobrevivido. La tasa de recurrencia de este tipo de ictus es aproximadamente del 12% a los 3 meses, más elevada que la de los ictus no cardioembólicos. La gravedad y discapacidad resultantes del ictus cardioembólico son importantes, mayores que las del no cardioembólico. La edad, los antecedentes de ictus o ataque isquémico transitorio previo, la hipertensión arterial, la diabetes y la insuficiencia cardíaca actúan en los ictus con fibrilación auricular como factores de riesgo añadido para futuras embolias, pudiendo alcanzar tasas de embolia de hasta más del 20% al año, por lo que su prevención y tratamiento son de suma importancia.
Context.
Most studies devoted to Herbig Ae/Be stars (HAeBes) assume solar metallicity. However, the stellar metallicity, M/H, is a fundamental parameter that can strongly differ depending on the ...source and may have important implications for planet formation. It has been proposed that the deficit of refractory elements observed in the surfaces of some HAeBes may be linked to the presence of cavities in their disks and is likely caused by Jovian planets that trap the metal-rich content.
Aims.
This work aims to provide a robust test on the previous proposal by analyzing the largest sample of HAeBes characterized by homogeneously derived M/H values and stellar and circumstellar properties.
Methods.
The spectra of 67 HAeBes, along with their well-known properties drawn from our previous work, have been collected from the ESO Science Archive Facility. Their M/H values were derived based on the comparison with Kurucz synthetic models. Statistical analyses were carried out with the aim to test the potential relation between M/H and the Meeus group I sources, with spectral energy distributions (SEDs) associated with the presence of cavities potentially carved by giant planets. We critically analyzed the eventual link between M/H, the SED groups, and the presence of such planets.
Results.
Our statistical study robustly confirms that group I sources tend to have a lower M/H (typically ~ −0.10) than that of group II HAeBes (~ +0.14). A similar analysis involving SED-based transitional disks, with infrared excess only at wavelengths of ≥2.2 µm, does not reveal such a relation with M/H. This result indicates that not all processes capable of creating holes in the inner dust disks end up having an effect on the stellar abundances. The spatial distributions of group I and II sources are similar, at least within the available range of distances to the galactic centre and the galactic plane, for which the observed M/H differences are not driven by environmental effects. In addition, group I sources tend to have stronger (sub-) mm continuum emission presumably related to the presence of giant planets. Indeed, literature results indicate that disk substructures probably associated with the presence of giant planets are up to ten times more frequent in group I HAeBes than in group II. Finally, along with the metallicities derived for the whole sample, surface gravities and projected rotational velocities are additional outcomes reported in this work.
Conclusions.
We provide indirect evidence to suggest that giant planets are more frequent around group I/low M/H stars than around the rest of the HAeBes. However, a direct test of the previous hypothesis requires multiple detections of forming planets in their disks. Such detections have so far been limited to the candidate around the metal depleted (M/H = −0.35 ± −0.25) group I HAeBe star AB Aur, which is consistent with our findings.
Background: Few longitudinal studies have verified the clinical diagnosis of dementia based on clinical examinations. We evaluated the consistency of the clinical diagnosis of dementia over a period ...of 3 years of follow-up in a population-based, cohort study of older people in central Spain. Methods: Individuals (N = 5278) were evaluated at baseline (1994-1995) and at follow-up (1997-1998). The evaluation included a screening questionnaire for dementia and a neurological assessment. Results: Dementia screening consisted of a 37-item version of the Mini-Mental State Examination (MMSE) and the Pfeffer Functional Activities Questionnaire (FAQ). Study neurologists investigated those participants who screened positively (N = 713) as well as 843 who had screened negatively to test the sensitivity of the screening instruments or because they had a positive screening for other chronic neurological diseases. We detected 295 patients among those who screened positive and 13 among those who screened negatively. Three years follow-up evaluation demonstrated 14 diagnostic errors at baseline (4.5%) leading to a final number of 306 patients with dementia. The corrected prevalence of dementia was 5.8% (95% confidence interval CI 5.2-6.5). Conclusions: The diagnosis of dementia was highly accurate in this population-based, Spanish cohort study, and our prevalence figures agree with other European surveys. Given the high cost and difficulties of population rescreening and its relatively low yield, we conclude that a single 2-phase investigation (screening followed by clinical examination) provides accurate information for most population-based prevalence studies of dementia.
Our aim was to assess prevalence rates of cerebrovascular disease (CVD; stroke and transient ischemic attacks) according to age and gender in three populations in central Spain using data from the ...Neurological Disorders in Central Spain (NEDICES) study, a population-based survey of elderly participants.
Individuals from one suburban municipality of Greater Madrid (Las Margaritas neighborhood, Getafe), one urban district of Madrid (Lista) and one rural site (Arévalo county, Avila) were evaluated at baseline (n = 5,278). The evaluation included a screening questionnaire and a neurological assessment when possible. We used point prevalence with a reference date of May 1, 1994.
Of the 5,278 subjects, there were 186 prevalent stroke cases and 71 cases of transient ischemic attacks. Prevalence rates, adjusted to the standard European populations, were 4.9% for CVD (95% confidence interval CI = 4.3-5.4), 3.4% for stroke (95% CI = 2.9-3.9) and 1.3% for transient ischemic attacks (95% CI = 1.0-1.6) in the total population. Age-specific prevalence rates of CVD, stroke and transient ischemic attacks increased exponentially with advancing age. The prevalence rates of CVD, stroke and transient ischemic attacks were higher for men than for women. Prevalence figures were higher in the suburban area of Margaritas compared to the rural region.
In this study, the prevalence of stroke and transient ischemic attacks were higher in men and in urban areas. Central Spain would be a medium stroke prevalence zone.
Context.
Herbig Ae/Be stars (HAeBes) have so far been studied based on relatively small samples that are scattered throughout the sky. Their fundamental stellar and circumstellar parameters and ...statistical properties were derived with heterogeneous approaches before
Gaia
.
Aims.
Our main goal is to contribute to the study of HAeBes from the largest sample of such sources to date, for which stellar and circumstellar properties have been determined homogeneously from the analysis of the spectral energy distributions (SEDs) and
Gaia
EDR3 parallaxes and photometry.
Methods.
Multiwavelength photometry was compiled for 209 bona fide HAeBes for which
Gaia
EDR3 distances were estimated. Using the Virtual Observatory SED Analyser (VOSA), photospheric models were fit to the optical SEDs to derive stellar parameters, and the excesses at infrared (IR) and longer wavelengths were characterized to derive several circumstellar properties. A statistical analysis was carried out to show the potential use of such a large dataset.
Results.
The stellar temperature, luminosity, radius, mass, and age were derived for each star based on optical photometry. In addition, their IR SEDs were classified according to two different schemes, and their mass accretion rates, disk masses, and the sizes of the inner dust holes were also estimated uniformly. The initial mass function fits the stellar mass distribution of the sample within 2 <
M
*
∕
M
⊙
< 12. In this aspect, the sample is therefore representative of the HAeBe regime and can be used for statistical purposes when it is taken into account that the boundaries are not well probed. Our statistical study does not reveal any connection between the SED shape from the Meeus et al. (2001, A&A, 365, 476) classification and the presence of transitional disks, which are identified here based on the SEDs that show an IR excess starting at the K band or longer wavelengths. In contrast, only ~28% of the HAeBes have transitional disks, and the related dust disk holes are more frequent in HBes than in HAes (~34% vs. 15%). The relatively small inner disk holes and old stellar ages estimated for most transitional HAes indicate that photoevaporation cannot be the main mechanism driving disk dissipation in these sources. In contrast, the inner disk holes and ages of most transitional HBes are consistent with the photoevaporation scenario, although these results alone do not unambiguously discard other disk dissipation mechanisms.
Conclusions.
The complete dataset is available online through a Virtual Observatory-compliant archive, representing the most recent reference for statistical studies on the HAeBe regime. VOSA is a complementary tool for the future characterization of newly identified HAeBes.
Approximately one in four ischemic strokes is of cardioembolic origin. Non-valvular atrial fibrillation accounts for 50% of these cases, followed by myocardial infarction, intraventricular thrombus, ...valvular heart disease and a miscellany of causes. The incidence of embolic heart disease in the population could be about 30 cases per 100,000 inhabitants per year, and its prevalence between 5 and 10 cases per 1,000 persons aged 65 years or older. Hospital mortality is high, and 5-year survival is only one out of every five patients. The recurrence rate of this type of stroke is about 12% at 3 months, higher than that of non-cardioembolic stroke. The severity of cardioembolic strokes and the resulting disability are greater than with non-cardioembolic stroke. Age, a history of stroke or transient ischemic attack, hypertension, diabetes and heart failure play a role in stroke with atrial fibrillation as additional risk factors for future embolisms. Stroke rates can reach over 20% per year and therefore the prevention and treatment of these events are of paramount importance.
Context.
It has been hypothesized that the location of Herbig Ae/Be stars (HAeBes) within the empirical relation between the inner disk radius (
r
in
), inferred from
K
-band interferometry, and the ...stellar luminosity (
L
*
), is related to the presence of the innermost gas, the disk-to-star accretion mechanism, the dust disk properties inferred from the spectral energy distributions (SEDs), or a combination of these effects. However, no general observational confirmation has been provided to date.
Aims.
This work aims to test whether the previously proposed hypotheses do, in fact, serve as a general explanation for the distribution of HAeBes in the size–luminosity diagram.
Methods.
GRAVITY/VLTI spectro-interferometric observations at ~2.2 μm have been obtained for five HBes representing two extreme cases concerning the presence of innermost gas and accretion modes. V590 Mon, PDS 281, and HD 94509 show no excess in the near-ultraviolet, Balmer region of the spectra (Δ
D
B
), indicative of a negligible amount of inner gas and disk-to-star accretion, whereas DG Cir and HD 141926 show such strong Δ
D
B
values that cannot be reproduced from magnetospheric accretion, but probably come from the alternative boundary layer mechanism. In turn, the sample includes three Group I and two Group II stars based on the Meeus et al. SED classification scheme. Additional data for these and all HAeBes resolved through
K
-band interferometry have been compiled from the literature and updated using
Gaia
EDR3 distances, almost doubling previous samples used to analyze the size–luminosity relation.
Results.
We find no general trend linking the presence of gas inside the dust destruction radius or the accretion mechanism with the location of HAeBes in the size–luminosity diagram. Similarly, our data do not support the more recent hypothesis linking such a location and the SED groups. Underlying trends are present and must be taken into account when interpreting the size–luminosity correlation. In particular, it cannot be statistically ruled out that this correlation is affected by dependencies of both
L
*
and
r
in
on the wide range of distances to the sources. Still, it is argued that the size–luminosity correlation is most likely to be physically relevant in spite of the previous statistical warning concerning dependencies on distance.
Conclusions.
Different observational approaches have been used to test the main scenarios proposed to explain the scatter of locations of HAeBes in the size–luminosity diagram. However, none of these scenarios have been confirmed as a fitting general explanation and this issue remains an open question.
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