Scattered light mapping of protoplanetary disks

High-contrast scattered light observations have revealed the surface morphology of several dozens of protoplanetary disks at optical and near-infrared wavelengths. Inclined disks offer the opportunity to measure part of the phase function of the dust grains that reside in the disk surface which is essential for our understanding of protoplanetary dust properties and the early stages of planet formation. We aim to construct a method which takes into account how the flaring shape of the scattering surface of an (optically thick) protoplanetary disk projects onto the image plane of the observer. This allows us to map physical quantities (scattering radius and scattering angle) onto scattered light images and retrieve stellar irradiation corrected (r^2-scaled) images and dust phase functions. We apply the method on archival polarized intensity images of the protoplanetary disk around HD 100546 that were obtained with VLT/SPHERE in R'-band and VLT/NACO in H- and Ks-band. The brightest side of the r^2-scaled R'-band polarized intensity image of HD 100546 changes from the far to the near side of the disk when a flaring instead of a geometrically flat disk surface is used for the r^2-scaling. The decrease in polarized surface brightness in the scattering angle range of ~40-70 deg is likely a result of the dust phase function and degree of polarization which peak in different scattering angle regimes. The derived phase functions show part of a forward scattering peak which indicates that large, aggregate dust grains dominate the scattering opacity in the disk surface. Projection effects of a protoplanetary disk surface need to be taken into account to correctly interpret scattered light images. Applying the correct scaling for the correction of stellar irradiation is crucial for the interpretation of the images and the derivation of the dust properties in the disk surface layer.Comment: Accepted for publication in A&A, 6 pages, 3 figure

Between-centre differences in care for in-hospital cardiac arrest:a prospective cohort study

Abstract Background Survival after in-hospital cardiac arrest is poor, but current literature shows substantial heterogeneity in reported survival rates. This study aims to evaluate care for patients suffering in-hospital cardiac arrest (IHCA) in the Netherlands by assessing between-hospital heterogeneity in outcomes and to explain this heterogeneity stemming from differences in case-mix or differences in quality of care. Methods A prospective multicentre study was conducted comprising 14 centres. All IHCA patients were included. The adjusted variation in structure and process indicators of quality of care and outcomes (in-hospital mortality and cerebral performance category [CPC] scale) was assessed with mixed effects regression with centre as random intercept. Variation was quantified using the median odds ratio (MOR), representing the expected odds ratio for poor outcome between two randomly picked centres. Results After excluding centres with less than 10 inclusions (2 centres), 701 patients were included of whom, 218 (32%) survived to hospital discharge. The unadjusted and case-mix adjusted MOR for mortality was 1.19 and 1.05, respectively. The unadjusted and adjusted MOR for CPC score was 1.24 and 1.19, respectively. In hospitals where personnel received cardiopulmonary resuscitation (CPR) training twice per year, 183 (64.7%) versus 290 (71.4%) patients died or were in a vegetative state, and 59 (20.8%) versus 68 (16.7%) patients showed full recovery (p < 0.001). Conclusion In the Netherlands, survival after IHCA is relatively high and between-centre differences in outcomes are small. The existing differences in survival are mainly attributable to differences in case-mix. Variation in neurological outcome is less attributable to case-mix

Peripheral Artery Disease Patients May Benefit More from Aggressive Secondary Prevention than Aneurysm Patients to Improve Survival

BACKGROUND AND AIMS: Although it has become clear that aneurysmal and occlusive arterial disease represent two distinct etiologic entities, it is still unknown whether the two vascular pathologies are prognostically different. We aim to assess the long-term vital prognosis of patients with abdominal aortic aneurysmal disease (AAA) or peripheral artery disease (PAD), focusing on possible differences in survival, prognostic risk profiles and causes of death. METHODS: Patients undergoing elective surgery for isolated AAA or PAD between 2003 and 2011 were retrospectively included. Differences in postoperative survival were determined using Kaplan-Meier and Cox regression analysis. Prognostic risk profiles were also established with Cox regression analysis. RESULTS: 429 and 338 patients were included in the AAA and PAD groups, respectively. AAA patients were older (71.7 vs. 63.3 years, p < 0.001), yet overall survival following surgery did not differ (HR: 1.16, 95% CI: 0.87-1.54). Neither was type of vascular disease associated with postoperative cardiovascular nor cancer-related death. However, in comparison with age- and gender-matched general populations, cardiovascular mortality was higher in PAD than AAA patients (48.3% vs. 17.3%). Survival of AAA and PAD patients was negatively affected by age, history of cancer and renal insufficiency. Additional determinants in the PAD group were diabetes and ischemic heart disease. CONCLUSIONS: Long-term survival after surgery for PAD and AAA is similar. However, overall life expectancy is significantly worse among PAD patients. The contribution of cardiovascular disease towards mortality in PAD patients warrants more aggressive secondary prevention to reduce cardiovascular mortality and improve longevity

Clinical prediction model to identify vulnerable patients in ambulatory surgery: towards optimal medical decision-making

__Background:__ Ambulatory surgery patients are at risk of adverse psychological outcomes such as anxiety, aggression, fatigue, and depression. We developed and validated a clinical prediction model to identify patients who were vulnerable to these psychological outcome parameters. __Methods:__ We prospectively assessed 383 mixed ambulatory surgery patients for psychological vulnerability, defined as the presence of anxiety (state/trait), aggression (state/trait), fatigue, and depression seven days after surgery. Three psychological vulnerability categories were considered–i.e., none, one, or multiple poor scores, defined as a score exceeding one standard deviation above the mean for each single outcome according to normative data. The following determinants were assessed preoperatively: sociodemographic (age, sex, level of education, employment status, marital status, having children, religion, nationality), medical (heart rate and body mass index), and psychological variables (self-esteem and self-efficacy), in addition to anxiety, aggression, fatigue, and depression. A prediction model was constructed using ordinal polytomous logistic regression analysis, and bootstrapping was applied for internal validation. The ordinal c-index (ORC) quantified the discriminative ability of the model, in addition to measures for overall model performance (Nagelkerke’s R2). __Results:__ In this population, 137 (36%) patients were identified as being psychologically vulnerable after surgery for at least one of the psychological outcomes. The most parsimonious and optimal prediction model combined sociodemographic variables (level of education, having children, and nationality) with psychological variables (trait anxiety, state/trait aggression, fatigue, and depression). Model performance was promising: R2 = 30% and ORC = 0.76 after correction for optimism. __Conclusion:__ This study identified a substantial group of vulnerable patients in ambulatory surgery. The proposed clinical prediction model could allow healthcare professionals the opportunity to identify vulnerable patients in ambulatory surgery, although additional modification and validation are needed. (ClinicalTrials.gov number, NCT01441843)

Coronary Revascularization Induces a Shift From Cardiac Toward Noncardiac Mortality Without Improving Survival in Vascular Surgery Patient

OBJECTIVE: Although evidence has shown that ischemic heart disease (IHD) in vascular surgery patients has a negative impact on the prognosis after surgery, it is unclear whether directed treatment of IHD may influence cause-specific and overall mortality. The objective of this study was to determine the prognostic implication of coronary revascularization (CR) on overall and cause-specific mortality in vascular surgery patients. METHODS: Patients undergoing surgery for abdominal aortic aneurysm, carotid artery stenosis, or peripheral artery disease in a university hospital in The Netherlands between January 2003 and December 2011 were retrospectively included. Survival estimates were obtained by Kaplan-Meier and Cox regression analysis. RESULTS: A total of 1104 patients were included. Adjusted survival analyses showed that IHD significantly increased the risk of overall mortality (hazard ratio [HR], 1.50; 95% confidence interval, 1.21-1.87) and cardiovascular death (HR, 1.93; 95% confidence interval, 1.35-2.76). Compared with those without CR, patients previously undergoing CR had similar overall mortality (HR, 1.38 vs 1.62; P = .274) and cardiovascular mortality (HR, 1.83 vs 2.02; P = .656). Nonrevascularized IHD patients were more likely to die of IHD (6.9% vs 35.7%), whereas revascularized IHD patients more frequently died of cardiovascular causes unrelated to IHD (39.1% vs 64.3%; P = .018). CONCLUSIONS: This study confirms the significance of IHD for postoperative survival of vascular surgery patients. CR was associated with lower IHD-related death rates. However, it failed to provide an overall survival benefit because of an increased rate of cardiovascular mortality unrelated to IHD. Intensification of secondary prevention regimens may be required to prevent this shift toward non-IHD-related death and thereby improve life expectancy

Early sac shrinkage predicts a low risk of late complications after endovascular aortic aneurysm repair

Background Aneurysm shrinkage has been proposed as a marker of successful endovascular aneurysm repair (EVAR). Patients with early postoperative shrinkage may experience fewer subsequent complications, and consequently require less intensive surveillance. Methods Patients undergoing EVAR from 2000 to 2011 at three vascular centres (in 2 countries), who had two imaging examinations (postoperative and after 6-18 months), were included. Maximum diameter, complications and secondary interventions during follow-up were registered. Patients were categorized according to early sac dynamics. The primary endpoint was freedom from late complications. Secondary endpoints were freedom from secondary intervention, postimplant rupture and direct (type I/III) endoleaks. Results Some 597 EVARs (71·1 per cent of all EVARs) were included. No shrinkage was observed in 284 patients (47·6 per cent), moderate shrinkage (5-9 mm) in 142 (23·8 per cent) and major shrinkage (at least 10 mm) in 171 patients (28·6 per cent). Four years after the index imaging, the rate of freedom from complications was 84·3 (95 per cent confidence interval 78·7 to 89·8), 88·1 (80·6 to 95·5) and 94·4 (90·1 to 98·7) per cent respectively. No shrinkage was an independent risk factor for late complications compared with major shrinkage (hazard ratio (HR) 3·11; P < 0·001). Moderate compared with major shrinkage (HR 2·10; P = 0·022), early postoperative complications (HR 3·34; P < 0·001) and increasing abdominal aortic aneurysm baseline diameter (HR 1·02; P = 0·001) were also risk factors for late complications. Freedom from secondary interventions and direct endoleaks was greater for patients with major sac shrinkage. Conclusion Early change in aneurysm sac diameter is a strong predictor of late complications after EVAR. Patients with major sac shrinkage have a very low risk of complications for up to 5 years. This parameter may be used to tailor postoperative surveillance. Towards personalized surveillanc

Exploring dust around HD142527 down to 0.025" / 4au using SPHERE/ZIMPOL

We have observed the protoplanetary disk of the well-known young Herbig star HD 142527 using ZIMPOL Polarimetric Differential Imaging with the VBB (Very Broad Band, ~600-900nm) filter. We obtained two datasets in May 2015 and March 2016. Our data allow us to explore dust scattering around the star down to a radius of ~0.025" (~4au). The well-known outer disk is clearly detected, at higher resolution than before, and shows previously unknown sub-structures, including spirals going inwards into the cavity. Close to the star, dust scattering is detected at high signal-to-noise ratio, but it is unclear whether the signal represents the inner disk, which has been linked to the two prominent local minima in the scattering of the outer disk, interpreted as shadows. An interpretation of an inclined inner disk combined with a dust halo is compatible with both our and previous observations, but other arrangements of the dust cannot be ruled out. Dust scattering is also present within the large gap between ~30 and ~140au. The comparison of the two datasets suggests rapid evolution of the inner regions of the disk, potentially driven by the interaction with the close-in M-dwarf companion, around which no polarimetric signal is detected.Comment: 11 pages, 7 figures, accepted for publication in A

Immediate postoperative high-sensitivity troponin T concentrations and long-term patient-reported

BACKGROUND: Myocardial injury after noncardiac surgery is associated with mortality and major adverse postoperative cardiovascular events. The effect of postoperative troponin concentrations on patient-reported health-related quality of life (HRQoL) is unknown. OBJECTIVE: The study examined the association between immediate postoperative troponin concentrations and self-reported HRQoL 1 year after surgery. DESIGN: Prospective cohort study. SETTING: Single-centre tertiary care hospital in the Netherlands between July 2012 and 2015. PATIENTS: Patients aged at least 60 years undergoing moderate and major noncardiac surgery.None. MAIN OUTCOME MEASURES: HRQoL total score was assessed with the EuroQol five-dimensional questionnaire. Tobit regression analysis was used to determine the association between postoperative troponin concentrations and 1-year HRQoL. Peak high-sensitivity troponin T values were divided into four categories: less than 14, 14 to 49, 50 to 149 and at least 150 ng l. RESULTS: A total of 3085 patients with troponin measurements were included. 2634 (85.4%) patients were alive at 1-year follow-up of whom 1297 (49.2%) returned a completed questionnaire. The median score for HRQoL was 0.82 (0.85, 0.81, 0.77 and 0.71 per increasing troponin category). Multivariable analysis revealed betas of -0.06 [95% confidence interval (CI) -0.09 to -0.02], -0.11 (95% CI -0.18 to -0.04) and -0.18 (95% CI -0.29 to -0.07) for troponin levels of 14 to 49, 50 to 149 and at least 150 ng l when compared with values less than 14 ng l. Other independent predictors for lower HRQoL were chronic obstructive pulmonary disease, female sex, peripheral arterial disease and increasing age. CONCLUSION: Higher levels of postoperative troponin measured immediately after surgery were independently associated with lower self-reported HRQoL total score at 1-year follow-up