n- исчисление – реалистичная формализация класса переписывающих систем

Предложен новый формализм типизированного η-исчисления в качестве теоретической основы для по-строения специальных классов систем программирования на основе переписывающих правил. Форма-лизм использует упорядоченные неконфлюэнтные множества правил переписывания и взаимодействие с программным окружением, что позволяет расширить возможности программирования динамических приложений

Spinal arteriovenous shunts presenting as intracranial subarachnoid haemorrhage

Item does not contain fulltextBACKGROUND: In approximately 5% of patients with intracranial subarachnoid haemorrhage (SAH), the cause is another than a ruptured aneurysm or perimesencephalic haemorrhage. One of these causes is a spinal arteriovenous shunt (SAVS). The aim of this study was to investigate the characteristics of patients with SAVS who present with intracranial SAH without symptoms and signs suggesting a spinal cause. METHODS: We systematically reviewed the literature and searched the SAH database of the University Medical Center Utrecht, The Netherlands, for patients with SAVS presenting with intracranial SAH and studied the characteristics of patients with SAVS whose clinical presentation mimicked intracranial SAH caused by rupture of a saccular aneurysm. RESULTS: Thirty-five patients were identified after a review of the literature. In our SAH database, comprising 2142 patients included in the period 1985-2004, we found one patient (0.05%, 95 % CI 0.006- 0.3%). SAH due to SAVS occurred at any age (4-72 years). The SAVS was located at the craniocervical junction in 14 patients, at the cervical level in 11, and at the thoracolumbar level in the remaining 11 patients. The majority of patients (n = 26, 72%) had no disabling deficits at discharge or follow-up. CONCLUSION: Rupture of a SAVS presenting as intracranial SAH is rare and can occur at any age. The SAVS can be located not only at the craniocervical junction or cervical level but also in the thoracolumbar region. Most patients with SAVS presenting as intracranial SAH have a good recovery

Size of third and fourth ventricle in obstructive and communicating acute hydrocephalus after aneurysmal subarachnoid hemorrhage

In patients with acute hydrocephalus after aneurysmal subarachnoid haemorrhage (SAH), lumbar drainage is possible if the obstruction is in the subarachnoid space (communicating hydrocephalus). In case of intraventricular obstruction (obstructive hydrocephalus), ventricular drainage is the only option. A small fourth ventricle is often considered a sign of obstructive hydrocephalus. We investigated whether the absolute or relative size of the fourth ventricle can indeed distinguish between these two types of hydrocephalus. On CT-scans of 76 consecutive patients with acute headache but normal CT and CSF, we measured the cross-sectional surface of the third and fourth ventricle to obtain normal planimetric values. Subsequently we performed the same measurements on 117 consecutive SAH patients with acute hydrocephalus. These patients were divided according to the distribution of blood on CT-scan into three groups: mainly intraventricular blood (n = 15), mainly subarachnoid blood (n = 54) and both intraventricular and subarachnoid blood (n = 48). The size of the fourth ventricle exceeded the upper limit of normal in 2 of the 6 (33%) patients with intraventricular blood but without haematocephalus, and in 15 of the 54 (28%) patients with mainly subarachnoid blood. The mean ratio between the third and fourth ventricle was 1.45 (SD 0.66) in patients with intraventricular blood and 1.42 (SD 0.91) in those with mainly subarachnoid blood. Neither fourth ventricular size nor the ratio between the third and fourth ventricles discriminates between the two groups. A small fourth ventricle does not necessarily accompany obstructive hydrocephalus and is therefore not a contraindication for lumbar drainage

Secondary infarction in single or in multiple vascular territories: two different entities following subarachnoid hemorrhage?

The pathogenesis of secondary infarctions (SI) after aneurysmal subarachnoid hemorrhage (SAH) is poorly understood. To assess whether SI in single (SSI) or multiple (MSI) vascular territories represent different disease entities, we compared clinical profiles of patients with these patterns of SI. CT/MRI-examinations of 448 patients were reviewed for new infarctions within 28 days after SAH, and categorized into SSI or MSI. Only patients with adequate follow-up imaging excluding any new infarctions were included for analysis (269 patients). Procedure-related infarctions were excluded. Odds ratios (ORs) with corresponding 95% confidence intervals (CI) were calculated for patients with SSI or MSI versus patients without SI to analyze differences in demographic characteristics, vascular risk factors, disease-related characteristics and treatment modalities. Thirty-six patients had SSI, 53 MSI and 180 no SI. ORs in MSI-patients were >1.5 times higher compared with ORs in SSI-patients for multiple vascular risk factors [MSI:5.4 (2.3–13) versus SSI:1.2 (0.5–2.8)], poor clinical condition on admission [MSI:4.6 (2.4–8.9) versus SSI:2.4 (1.1–5.2)], initial loss of consciousness [MSI:2.6 (1.3–5.3) versus SSI:1.1 (0.5–2.3)] and large amounts of intraventricular blood [MSI:2.9 (1.4–5.8) versus SSI:1.5 (0.7–3.2)]. In multivariate analysis ORs remained higher in MSI for presence of multiple vascular risk factors [MSI:1.9 (1.2–2.9) versus SSI:1.1 (0.8–1.7)] and initial loss of consciousness [MSI:3.0 (1.0–8.9) versus SSI:1.6 (0.6–4.0)]. Our findings suggest that SSI and MSI after SAH are not distinct disease entities. MSI was related to the same characteristics as SSI but to a larger extent, specifically to the presence of multiple vascular risk factors, initial loss of consciousness, larger amounts of intraventricular blood, and poor clinical status on admission

Chance of aneurysm in patients suspected of SAH who have a ‘negative’ CT scan but a ‘positive’ lumbar puncture

In patients with sudden severe headache and a negative computed tomography (CT) scan, a lumbar puncture (LP) is performed to rule in or out a subarachnoid haemorrhage (SAH), but this procedure is under debate. In a hospital-based series of 30 patients with sudden headache, a negative CT scan but a positive LP (defined as detection of bilirubin >0.05 at wavelength 458 nm), we studied the chance of harbouring an aneurysm and the clinical outcome. Aneurysms were found in none of both patients who presented within 3 days, in 8 of the 18 (44%) who presented within 4–7 days and in 5 of the 10 (50%) who presented within 8–14 days. Of the 13 patients with an aneurysm, 3 (23%) had poor outcome. In patients who present late after sudden headache, the yield in terms of aneurysms is high in those who have a positive lumbar puncture. In patients with an aneurysm as cause of the positive lumbar puncture, outcome is in the same range as in SAH patients admitted in good clinical condition

Apixaban versus no anticoagulation after anticoagulation-associated intracerebral haemorrhage in patients with atrial fibrillation in the Netherlands (APACHE-AF):a randomised, open-label, phase 2 trial

Background In patients with atrial fibrillation who survive an anticoagulation-associated intracerebral haemorrhage, a decision must be made as to whether restarting or permanently avoiding anticoagulation is the best long-term strategy to prevent recurrent stroke and other vascular events. In APACHE-AF, we aimed to estimate the rates of non-fatal stroke or vascular death in such patients when treated with apixaban compared with when anticoagulation was avoided, to inform the design of a larger trial. Methods APACHE-AF was a prospective, randomised, open-label, phase 2 trial with masked endpoint assessment, done at 16 hospitals in the Netherlands. Patients who survived intracerebral haemorrhage while treated with anticoagulation for atrial fibrillation were eligible for inclusion 7-90 days after the haemorrhage. Participants also had a CHA2DS2-VASc score of at least 2 and a score on the modified Rankin scale (mRS) of 4 or less. Participants were randomly assigned (1:1) to receive oral apixaban (5 mg twice daily or a reduced dose of 2.5 mg twice daily) or to avoid anticoagulation (oral antiplatelet agents could be prescribed at the discretion of the treating physician) by a central computerised randomisation system, stratified by the intention to start or withhold antiplatelet therapy in participants randomised to avoiding anticoagulation, and minimised for age and intracerebral haemorrhage location. The primary outcome was a composite of non-fatal stroke or vascular death, whichever came first, during a minimum follow-up of 6 months, analysed using Cox proportional hazards modelling in the intention-to-treat population. APACHE-AF is registered with ClinicalTrials.gov (NCT02565693) and the Netherlands Trial Register (NL4395), and the trial is closed to enrolment at all participating sites. Findings Between Jan 15, 2015, and July 6, 2020, we recruited 101 patients (median age 78 years [IQR 73-83]; 55 [54%] were men and 46 [46%] were women; 100 [99%] were White and one [1%] was Black) a median of 46 days (IQR 21-74) after intracerebral haemorrhage. 50 were assigned to apixaban and 51 to avoid anticoagulation (of whom 26 [51%] started antiplatelet therapy). None were lost to follow-up. Over a median follow-up of 1.9 years (IQR 1.0-3.1; 222 person-years), non-fatal stroke or vascular death occurred in 13 (26%) participants allocated to apixaban (annual event rate 12.6% [95% CI 6.7-21.5]) and in 12 (24%) allocated to avoid anticoagulation (11.9% [95% CI 6.2-20.8]; adjusted hazard ratio 1.05 [95% CI 0.48-2.31]; p=0.90). Serious adverse events that were not outcome events occurred in 29 (58%) of 50 participants assigned to apixaban and 29 (57%) of 51 assigned to avoid anticoagulation. Interpretation Patients with atrial fibrillation who had an intracerebral haemorrhage while taking anticoagulants have a high subsequent annual risk of non-fatal stroke or vascular death, whether allocated to apixaban or to avoid anticoagulation. Our data underline the need for randomised controlled trials large enough to allow identification of subgroups in whom restarting anticoagulation might be either beneficial or hazardous. Copyright (C) 2021 Elsevier Ltd. All rights reserved

Multidisciplinary Consensus on Assessment of Unruptured Intracranial Aneurysms Proposal of an International Research Group

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