Aneurysmal and clinical characteristics as risk factors for intracerebral haematoma from aneurysmal rupture

Intracerebral haematoma (ICH) occurs in one-third of patients with aneurysmal subarachnoid haemorrhage (SAH) and is associated with poor prognosis. Identification of risk factors for ICH from aneurysmal rupture may help in balancing risks of treatment of unruptured aneurysms. We assessed potential clinical and aneurysmal risk factors for ICH from aneurysmal rupture. In all 310 SAH patients admitted to our service between 2005 and 2007, we compared clinical risk factors (gender, age, smoking, hypertension, history of SAH and family history) of patients with and without an ICH. From the latest admitted, 50 patients with and 50 without ICH, we compared the location, shape and direction of blood flow of the aneurysms on CT-angiography. Relative risks (RRs) of ICH were 1.2 (95% confidence interval, CI):0.7–1.8) for males, 1.0 (95%CI:0.7–1.4) for age ≥55 year, 1.0 (95%CI:0.6–1.6) for smoking, 0.9 (95%CI:0.5–1.5) for hypertension, 0.6 (95%CI:0.1–3.8) for history of SAH and 0.5 (95%CI:0.2–1.3) for family history of SAH. RRs of ICH were 1.8 (95%CI:1.2–2.5) for MCA aneurysms, 0.5 (95%CI:0.3–1.0) for ICA aneurysms, 0.4 (95%CI:0.1–1.3) for posterior circulation aneurysms, and 0.7 (95%CI:0.3–1.3) for multilobed aneurysms. The RRs of other aneurysmal characteristics varied between 0.9 and 1.2. Patients with MCA aneurysms are at a higher risk of developing ICH. The other aneurysmal or clinical factors have no or only minor influence on the risk of ICH after rupture and are, therefore, not helpful in deciding on treatment of unruptured aneurysms

Algorithmic statistics: forty years later

Algorithmic statistics has two different (and almost orthogonal) motivations. From the philosophical point of view, it tries to formalize how the statistics works and why some statistical models are better than others. After this notion of a "good model" is introduced, a natural question arises: it is possible that for some piece of data there is no good model? If yes, how often these bad ("non-stochastic") data appear "in real life"? Another, more technical motivation comes from algorithmic information theory. In this theory a notion of complexity of a finite object (=amount of information in this object) is introduced; it assigns to every object some number, called its algorithmic complexity (or Kolmogorov complexity). Algorithmic statistic provides a more fine-grained classification: for each finite object some curve is defined that characterizes its behavior. It turns out that several different definitions give (approximately) the same curve. In this survey we try to provide an exposition of the main results in the field (including full proofs for the most important ones), as well as some historical comments. We assume that the reader is familiar with the main notions of algorithmic information (Kolmogorov complexity) theory.Comment: Missing proofs adde

Effect of weekend admission on in-hospital mortality and functional outcomes for patients with acute subarachnoid haemorrhage (SAH)

BACKGROUND: Aneurysmal subarachnoid haemorrhage (aSAH) is an acute cerebrovascular event with high socioeconomic impact as it tends to affect younger patients. The recent NCEPOD study looking into management of aSAH has recommended that neurovascular units in the United Kingdom should aim to secure cerebral aneurysms within 48 h and that delays because of weekend admissions can increase the mortality and morbidity attributed to aSAH. METHOD: We used data from a prospective audit of aSAH patients admitted between January 2009 and December 2011. The baseline demographic and clinical features of the weekend and weekday groups were compared using the chi-squared test and T-test. Cox proportional hazards models (Proc Phreg in SAS) were used to calculate the adjusted overall hazard of in-hospital death associated with admission on weekend, adjusting for age, sex, baseline WFNS grade, type of treatment received and time from scan to treatment. Sliding dichotomy analysis was used to estimate the difference in outcomes after SAH at 3 months in weekend and weekday admissions. RESULTS: Those admitted on weekends had a significantly higher scan to treatment time (83.05 ± 83.4 h vs 40.4 ± 53.4 h, P < 0.0001) and admission to treatment (71.59 ± 79.8 h vs 27.5 ± 44.3 h, P < 0.0001) time. After adjustments for adjusted for relevant covariates weekend admission was statistically significantly associated with excess in-hospital mortality (HR = 2.1, CL [1.13–4.0], P = 0.01). After adjustments for all the baseline covariates, the sliding dichotomy analysis did not show effects of weekend admission on long-term outcomes on the good, intermediate and worst prognostic bands. CONCLUSIONS: This study provides important data showing excess in-hospital mortality of patients with SAH on weekend admissions served by the United Kingdom’s National Health Service.; However, there were no effects of weekend admission on long-term outcomes. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00701-016-2746-z) contains supplementary material, which is available to authorized users

Angiopoietin-1 is associated with cerebral vasospasm and delayed cerebral ischemia in subarachnoid hemorrhage

<p>Abstract</p> <p>Background</p> <p>Angiopoietin-1 (Ang-1) and -2 (Ang-2) are keyplayers in the regulation of endothelial homeostasis and vascular proliferation. Angiopoietins may play an important role in the pathophysiology of cerebral vasospasm (CVS). Ang-1 and Ang-2 have not been investigated in this regard so far.</p> <p>Methods</p> <p>20 patients with subarachnoid hemorrhage (SAH) and 20 healthy controls (HC) were included in this prospective study. Blood samples were collected from days 1 to 7 and every other day thereafter. Ang-1 and Ang-2 were measured in serum samples using commercially available enzyme-linked immunosorbent assay. Transcranial Doppler sonography was performed to monitor the occurrence of cerebral vasospasm.</p> <p>Results</p> <p>SAH patients showed a significant drop of Ang-1 levels on day 2 and 3 post SAH compared to baseline and HC. Patients, who developed Doppler sonographic CVS, showed significantly lower levels of Ang-1 with a sustained decrease in contrast to patients without Doppler sonographic CVS, whose Ang-1 levels recovered in the later course of the disease. In patients developing cerebral ischemia attributable to vasospasm significantly lower Ang-1 levels have already been observed on the day of admission. Differences of Ang-2 between SAH patients and HC or patients with and without Doppler sonographic CVS were not statistically significant.</p> <p>Conclusions</p> <p>Ang-1, but not Ang-2, is significantly altered in patients suffering from SAH and especially in those experiencing CVS and cerebral ischemia. The loss of vascular integrity, regulated by Ang-1, might be in part responsible for the development of cerebral vasospasm and subsequent cerebral ischemia.</p