Is Learning in Biological Neural Networks Based on Stochastic Gradient Descent? An Analysis Using Stochastic Processes

In recent years, there has been an intense debate about how learning in biological neural networks (BNNs) differs from learning in artificial neural networks. It is often argued that the updating of connections in the brain relies only on local information, and therefore a stochastic gradient-descent type optimization method cannot be used. In this article, we study a stochastic model for supervised learning in BNNs. We show that a (continuous) gradient step occurs approximately when each learning opportunity is processed by many local updates. This result suggests that stochastic gradient descent may indeed play a role in optimizing BNNs.

Comprehensive Venous Outflow Predicts Functional Outcomes in Patients with Acute Ischemic Stroke Treated by Thrombectomy

BACKGROUND AND PURPOSE

Cortical venous outflow has emerged as a robust measure of collateral blood flow in acute ischemic stroke. The addition of deep venous drainage to this assessment may provide valuable information to further guide the treatment of these patients.

MATERIALS AND METHODS

We performed a multicenter retrospective cohort study of patients with acute ischemic stroke treated by thrombectomy between January 2013 and January 2021. The internal cerebral veins were scored on a scale of 0-2. This metric was combined with existing cortical vein opacification scores to create a comprehensive venous outflow score from 0 to 8 and stratify patients as having favorable-versus-unfavorable comprehensive venous outflow. Outcome analyses were primarily conducted using the Mann-Whitney U and χ2 tests.

RESULTS

Six hundred seventy-eight patients met the inclusion criteria. Three hundred fifteen were stratified as having favorable comprehensive venous outflow (mean age, 73 years; range, 62-81 years; 170 men), and 363, as having unfavorable comprehensive venous outflow (mean age, 77 years; range, 67-85 years; 154 men). There were significantly higher rates of functional independence (mRS 0-2; 194/296 versus 37/352, 66% versus 11%, P < .001) and excellent reperfusion (TICI 2c/3; 166/313 versus 142/358, 53% versus 40%, P < .001) in patients with favorable comprehensive venous outflow. There was a significant increase in the association of mRS with the comprehensive venous outflow score compared with the cortical vein opacification score (-0.74 versus -0.67, P = .006).

CONCLUSIONS

A favorable comprehensive venous profile is strongly associated with functional independence and excellent postthrombectomy reperfusion. Future studies should focus on patients with venous outflow status that is discrepant with the eventual outcome.

Application of 89Zr-DFO*-immuno-PET to assess improved target engagement of a bispecific anti-amyloid-ß monoclonal antibody

PURPOSE

The recent conditional FDA approval of Aducanumab (Adu) for treating Alzheimer's disease (AD) and the continued discussions around that decision have increased interest in immunotherapy for AD and other brain diseases. Reliable techniques for brain imaging of antibodies may guide decision-making in the future but needs further development. In this study, we used ⁸⁹Zr-immuno-PET to evaluate the targeting and distribution of a bispecific brain-shuttle IgG based on Adu with transferrin receptor protein-1 (TfR1) shuttling mechanism, mAbAdu-scFab8D3, designated Adu-8D3, as a candidate theranostic for AD. We also validated the ⁸⁹Zr-immuno-PET platform as an enabling technology for developing new antibody-based theranostics for brain disorders.

METHODS

Adu, Adu-8D3, and the non-binding control construct B12-8D3 were modified with DFO*-NCS and radiolabeled with ⁸⁹Zr. APP/PS1 mice were injected with ⁸⁹Zr-labeled mAbs and imaged on days 3 and 7 by positron emission tomography (PET). Ex vivo biodistribution was performed on day 7, and ex vivo autoradiography and immunofluorescence staining were done on brain tissue to validate the PET imaging results and target engagement with amyloid-β plaques. Additionally, [⁸⁹Zr]Zr-DFO*-Adu-8D3 was evaluated in 3, 7, and 10-month-old APP/PS1 mice to test its potential in early stage disease.

RESULTS

A 7-fold higher brain uptake was observed for [⁸⁹Zr]Zr-DFO*-Adu-8D3 compared to [⁸⁹Zr]Zr-DFO*-Adu and a 2.7-fold higher uptake compared to [⁸⁹Zr]Zr-DFO*-B12-8D3 on day 7. Autoradiography and immunofluorescence of [⁸⁹Zr]Zr-DFO*-Adu-8D3 showed co-localization with amyloid plaques, which was not the case with the Adu and B12-8D3 conjugates. [⁸⁹Zr]Zr-DFO*-Adu-8D3 was able to detect low plaque load in 3-month-old APP/PS1 mice.

CONCLUSION

⁸⁹Zr-DFO*-immuno-PET revealed high and specific uptake of the bispecific Adu-8D3 in the brain and can be used for the early detection of Aβ plaque pathology. Here, we demonstrate that ⁸⁹Zr-DFO*-immuno-PET can be used to visualize and quantify brain uptake of mAbs and contribute to the evaluation of biological therapeutics for brain diseases.

Validation of a suite of ERP and QEEG biomarkers in a pre-competitive, industry-led study in subjects with schizophrenia and healthy volunteers

OBJECTIVE

Complexity and lack of standardization have mostly limited the use of event-related potentials (ERPs) and quantitative EEG (QEEG) biomarkers in drug development to small early phase trials. We present results from a clinical study on healthy volunteers (HV) and patients with schizophrenia (SZ) that assessed test-retest, group differences, variance, and correlation with functional assessments for ERP and QEEG measures collected at clinical and commercial trial sites with standardized instrumentation and methods, and analyzed through an automated data analysis pipeline.

METHODS

81 HV and 80 SZ were tested at one of four study sites. Subjects were administered two ERP/EEG testing sessions on separate visits. Sessions included a mismatch negativity paradigm, a 40 Hz auditory steady-state response paradigm, an eyes-closed resting state EEG, and an active auditory oddball paradigm. SZ subjects were also tested on the Brief Assessment of Cognition (BAC), Positive and Negative Syndrome Scale (PANSS), and Virtual Reality Functional Capacity Assessment Tool (VRFCAT).

RESULTS

Standardized ERP/EEG instrumentation and methods ensured few test failures. The automated data analysis pipeline allowed for near real-time analysis with no human intervention. Test-retest reliability was fair-to-excellent for most of the outcome measures. SZ subjects showed significant deficits in ERP and QEEG measures consistent with published academic literature. A subset of ERP and QEEG measures correlated with functional assessments administered to the SZ subjects.

CONCLUSIONS

With standardized instrumentation and methods, complex ERP/EEG testing sessions can be reliably performed at clinical and commercial trial sites to produce high-quality data in near real-time.

Long-term neurological intact survival and quality of life after refractory out-of-hospital cardiac arrest treated with rescue mechanical circulatory support

Background

Mechanical circulatory support (MCS) with either veno-arterial extracorporeal membrane oxygenation (V-A ECMO) or Impella has emerged as a rescue therapy for refractory out-of-hospital cardiac arrest (OHCA). However, only short-term outcome is specified and most studies do not report follow-up beyond six months. Long-term survival and quality of life in this high-risk population remains unknown.

Purpose

To determine long-term neurological intact survival and quality of life in patients with refractory OHCA treated with MCS.

Methods

This was an observational, single-centre study of OHCA-patients from January 2015 to December 2019. Patients treated with MCS for OHCA were compared with patients receiving conventional cardiopulmonary resuscitation (CPR). A follow-up of long-term survivors in the MCS group was conducted (&gt;1 year after arrest). This included health related quality of life questionaries (Short Form-36 [SF-36]) and assessment of neurological function with Cerebral Performance Category (CPC). Good neurological outcome was defined as CPC 1 and CPC 2.

Results

A total of 1015 with OHCA were included; 101 received MCS for refractory cardiac arrest. Among these V-A ECMO was deployed in 97 patients and Impella in 4 patients. The MCS group had significantly longer low-flow times compared to the conventional group (105 [IQR, 94–123] minutes versus 18 [IQR 10–39] minutes) and were more metabolically deranged upon arrival at hospital (Table 1). In patients receiving MCS, the hospital discharge rate was 27% and good neurological outcome was seen in 93% among patients discharged. At follow-up, 15 out of 21 long-term survivors participated. Median follow-up time was 4.8±1.6 (range 2.8–6.1 years). Mean age at follow-up was 61±7.3 years, 11 (73%) were men. Neurological outcome with CPC 1 was found in 12 patients (80%), with CPC 2 in 2 patients (13%), and with CPC 3 in 1 patient (7%). Two had improved neurological status from CPC 2 to CPC 1 since discharge. Mean scores of the SF-36 revealed an overall high level of psychical and mental health in long-term survivors (Figure 1).

Conclusion

Long-term survival with good neurological outcome was high in patients with refractory OHCA treated with MCS despite prolonged resuscitation and severe metabolic derangement. These patients may expect a reasonable quality of life after discharge.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Department of Cardiology, Aarhus University HospitalSnedkermester Sophus Jacobsen og hustru Astrid Jacobsens Fond

Extracorporeal cardiopulmonary resuscitation: a national study on the association between survival and biomarkers of hypoperfusion, inflammation, and organ failure

Background

In refractory out-of-hospital cardiac arrest (OHCA) with prolonged whole-body ischemia, global tissue injury proceeds even after establishment of circulation with extracorporeal cardiopulmonary resuscitation (ECPR).

Purpose

We aimed to investigate the role of biomarkers reflecting hypoperfusion, inflammation, and organ injury in prognostication of patients with refractory OHCA managed with ECPR.

Methods

This nationwide retrospective study included 226 adults with refractory OHCA managed with ECPR in Denmark (2011–2020). Biomarkers at admission and consecutively two days after ECPR initiation were retrieved. Odds ratio (OR) of 90-day survival were assessed by logistic regression analyses. Cut-off values were calculated from area under the curve (AUC) via the Youden index.

Results

Fifty-six patients (25%) survived to hospital discharge, all were still alive after 90-days and 91% had a favorable neurological status at discharge. Factors independently associated with 90-day survival were: male sex, shockable presenting rhythm, low flow time, platelets, pH, lactate, C-reactive protein, lactate dehydrogenase (LDH), alkaline phosphatase (ALP), and creatine kinase MB (CK-MB) level. Comparing the ability of standard predictive variables (age, sex, shockable presenting rhythm, witnessed arrest, and low flow time) and selected biomarkers (from multivariate analyses) in predicting 90-day survival, biomarkers day 2 after OHCA were significantly better than standard variables (AUC 0.79 vs. 0.56, p=0.01).

Conclusion

Biomarkers of hypoperfusion (low lactate and high pH), inflammation (high platelets and CRP), and organ failure (low LDH, ALP, and CK-MB) were independently associated with 90-day survival. Biomarkers on day 2 after OHCA (d-dimer, ALP, and CK-MB) were more predictive of 90-day survival than standard predictive variables.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Odense University Hospital's and Rigshospitalet's Common Research Foundation

Correlates of late-onset antipsychotic treatment resistance

Introduction

There is emerging evidence of heterogeneity within treatment-resistance schizophrenia (TRS), with some people not responding to antipsychotic treatment from illness onset and a smaller group becoming treatment-resistant after an initial response period. It has been suggested that these groups have different aetiologies. Few studies have investigated socio-demographic and clinical differences between early and late onset of TRS.

Objectives

This study aims to investigate socio-demographic and clinical correlates of late-onset of TRS.

Methods

Using data from the electronic health records of the South London and Maudsley, we identified a cohort of people with TRS. Regression analyses were conducted to identify correlates of the length of treatment to TRS. Analysed predictors include gender, age, ethnicity, positive symptoms severity, problems with activities of daily living, psychiatric comorbidities, involuntary hospitalisation and treatment with long-acting injectable antipsychotics.

Results

We observed a continuum of the length of treatment until TRS presentation. Having severe hallucinations and delusions at treatment start was associated shorter duration of treatment until the presentation of TRS.

Conclusions

Our findings do not support a clear cut categorisation between early and late TRS, based on length of treatment until treatment resistance onset. More severe positive symptoms predict earlier onset of treatment resistance.

Disclosure

DFdF, GKS, EF and IR have received research funding from Janssen and H. Lundbeck A/S. RDH and HS have received research funding from Roche, Pfizer, Janssen and Lundbeck. SES is employed on a grant held by Cardiff University from Takeda Pharmaceutical Comp

Healthcare cost variation in patients with heart failure: a nationwide study

OBJECTIVE

Heart failure (HF) imposes a major economic burden; however, the individual management for patients varies, potentially leading to large cost heterogeneity. The aim of this study was to investigate the spectrum of health cost by patients with HF and factors associated with high direct health cost.

STUDY DESIGN

This was a nationwide, retrospective longitudinal study.

METHODS

Using Danish nationwide registries from 2012 to 2015, we identified all patients aged >18 years with a first-time diagnosis of HF. Total health costs were investigated using two perspectives-at index and during 3 years of follow-up. Patients were investigated by decile cost groups. A multivariable logistic regression was used to identify variables associated with being in the highest cost decile compared with the rest (90%).

RESULTS

A total of 11,170 patients with HF were included, and those in the highest cost decile (n = 1117, 10%) were younger (69 vs. 75 years), fewer were females (34% vs. 43%), and more were inpatients (83% vs. 70%) compared with the rest of the patients with HF (n = 10,053, 90%). Patients in the highest cost decile (10%) incurred a 30 times higher cost with a mean total health cost in index year of €86,607 compared with €2893 for patients in lowest cost decile (10%). The results were similar for 3 years aggregated (€139,473 vs. €4086), corresponding to a 34 times higher cost.

CONCLUSION

In patients with HF, a large total health cost heterogeneity exists with younger age, inpatient admittance, male sex, and comorbidities being associated with a higher likelihood of belonging to the highest cost group.

Mechanical circulatory support for refractory out-of-hospital cardiac arrest: a nationwide multicentre study

Background

Extracorporeal cardiopulmonary resuscitation (ECPR) has shown potential as a salvage therapy for patients with refractory out-of-hospital cardiac arrest (OHCA). Despite growing interest in and a growing body of literature on ECPR for refractory OHCA, robust evidence on patient eligibility is still lacking.

Purpose

To describe the survival, neurological outcome, and adherence to the national consensus with respect to use of ECPR for OHCA, and to identify factors associated with outcome.

Methods

Retrospective, observational cohort study of patients who underwent ECPR for OHCA at four cardiac arrest centres. Binary logistic regression and Kaplan-Meier survival curves were performed to assess association with 30-day mortality.

Results

A total of 259 patients receiving ECPR for OHCA between July 2011 and December 2020 were included in the study. Thirty-day survival was 26% and a good neurological outcome Cerebral Performance Category (CPC) 1–2 was observed in 94% of patients at discharge. Strict adherence to the national consensus showed a 30-day survival rate of 30%. Adding one or more of the following criteria to the national consensus: signs of life during cardiopulmonary resuscitation (CPR), pre-hospital low-flow &lt;100 minutes, pH &gt;6.8 and lactate &lt;15 mmol/L increased the survival rate to 48%, but would exclude 58% of the survivors from the current cohort. Logistic regression identified initial presenting rhythm with asystole (RR 1.36, 95% CI 1.18–1.57), pulseless electrical activity (PEA) (RR 1.20, 95% CI 1.03–1.41), initial pH &lt;6.8 (RR 1.28, 95% CI 1.12–1.46) and lactate levels &gt;15 mmol/L (RR 1.16, 95% CI 1.16–1.53) as factors associated with increased risk of 30-day mortality. Patients presenting signs of life during CPR had threefold higher survival rate than patients without signs of life (45% versus 13%, p&lt;0.001)

Conclusion

A high survival rate with a good neurological outcome was observed in this population of patients treated with ECPR for OHCA. Signs of life during CPR may aid the decision-making in the selection of appropriate candidates. Stringent patient selection for ECPR may produce higher survival rates but potentially withholds life-saving treatment in a significant proportion of survivors, why optimization of the selection criteria is still necessary.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): This work was supported by the Danish Heart Foundation [20-R142-A9498-22178]; and Health Research Foundation of Central Denmark Region [R64-A3178-B1349] Survival and adherence to consensusSigns of life during CPR

OP0072 SINGLE CELL SEQUENCING REVEALS CLONALLY EXPANDED CYTOTOXIC CD4+ T CELLS IN THE JOINTS OF ACPA+ RA PATIENTS

Background:

CD4+ T cells with cytotoxic functions (CD4+ CTL) have gained attention in recent years. Accumulating evidence supports their importance in defense against human viral infections such as CMV1, EBV2, dengue3, HIV4, 5 and SARS-CoV-26. Moreover, expansion of so called CD28null cytotoxic CD4+ T cells have been reported in the blood of patients with rheumatic diseases such as rheumatoid arthritis (RA)7, myositis8 and vasculitis9 as well as in cardiovascular diseases10.

Objectives:

Here, we aimed to investigate the presence and clonal expansion of CD4+ CTL in the peripheral blood (PB) and synovial fluid (SF) of RA patients using single cell technologies.

Methods:

We assessed the expression of cytotoxic effector molecules and transcription factors in CD4+ T cells in synovial fluid (n=21) and paired peripheral blood (n=16) from ACPA- and APCA+ RA patients by multi-parameter flow cytometry. We performed single cell sequencing, in combination with 5´ TCRab sequencing, on purified CD4+ T cells from the peripheral blood (PB) and synovial fluid (SF) of ACPA+ RA patients (n=7).

Results:

Flow cytometry experiments show that Granzyme-B+ Perforin-1+ CD4+ CTL are significantly increased in the SF of ACPA+ RA patients as compared to ACPA- RA patients (p=0.0072). The presence of CD4+ CTL could be confirmed by single cell sequencing in SF of each ACPA+ RA patient tested (n=7). Moreover, we found that the adhesion G-protein coupled receptor GPR56 is selectively expressed on the recently described peripheral helper (TPH) T-cell subset11 and associates with the expression of tissue resident memory markers LAG-3, CXCR6 and CD69. In blood, we confirmed a previous report12 showing that GPR56 delineates cytotoxic CD4+ T cells. Finally, expanded TCR clones expressing cytotoxic effector molecules were identified in synovial fluid of ACPA+ RA patients and, for some patients, in their corresponding peripheral blood.

Conclusion:

We identified GPR56 as a marker of TPH cells in SF of ACPA+ RA patients that associates with tissue residency receptors. The combination of single cell sequencing and multi-parameter flow cytometry highlights the importance of CD4+ CTL in ACPA+ RA and suggests a potential therapeutic target (Figure 1).

References:

[1]Casazza J. P. et al., J Exp Med2006,203 (13), 2865-77.

[2]Landais E. et al., Blood2004,103 (4), 1408-16.

[3]Kurane I. et al. J Exp Med1989,170 (3), 763-75.

[4]Appay V. et al. J Immunol2002,168 (11), 5954-8.

[5]Juno J. A. et al. Front Immunol2017,8, 19.

[6]Meckiff B. J. et al. Cell2020,183 (5), 1340-1353 e16.

[7]Schmidt D. et al. J Clin Invest1996,97 (9), 2027-37.

[8]Fasth A. E. et al. J Immunol2009,183 (7), 4792-9.

[9]Moosig F. et al. Clin Exp Immunol1998,114 (1), 113-8.

[10]Sato K. et al. J Exp Med2006,203 (1), 239-50.

[11]Rao D. A., et al. Nature2017,542 (7639), 110-114.

[12]Peng Y. M. et al. J Leukoc Biol2011,90 (4), 735-40.

Acknowledgements:

We thank the patients who donated samples and the medical staff at the Rheumatology Clinic of Karolinska University Hospital. Julia Boström, Gloria Rostvall, and Susana Hernandez Machado are acknowledged for organizing the sampling, storage, and administration of biomaterial. This study is supported by grants from Dr. Margaretha Nilssons, the Nanna Svartz, the Ulla and Gustaf af Ugglas foundations and the Swedish association against rheumatism.

Disclosure of Interests:

Alexandra Argyriou: None declared, Marc H Wadsworth II Employee of: Pfizer, Inc, Cambridge, MA 02139, United States, Adrian Lendvai: None declared, Stephen Christensen Employee of: Pfizer, Inc, Cambridge, MA 02139, United States, Aase Hensvold: None declared, Christina Gerstner: None declared, Kellie Kravarik Employee of: Pfizer, Inc, Cambridge, MA 02139, United States, Aaron Winkler Employee of: Pfizer, Inc, Cambridge, MA 02139, United States, Vivianne Malmström: None declared, Karine Chemin: None declared

Tissue at Risk and Ischemic Core Estimation Using Deep Learning in Acute Stroke

BACKGROUND AND PURPOSE

In acute stroke patients with large vessel occlusions, it would be helpful to be able to predict the difference in the size and location of the final infarct based on the outcome of reperfusion therapy. Our aim was to demonstrate the value of deep learning-based tissue at risk and ischemic core estimation. We trained deep learning models using a baseline MR image in 3 multicenter trials.

MATERIALS AND METHODS

Patients with acute ischemic stroke from 3 multicenter trials were identified and grouped into minimal (≤20%), partial (20%-80%), and major (≥80%) reperfusion status based on 4- to 24-hour follow-up MR imaging if available or into unknown status if not. Attention-gated convolutional neural networks were trained with admission imaging as input and the final infarct as ground truth. We explored 3 approaches: 1) separate: train 2 independent models with patients with minimal and major reperfusion; 2) pretraining: develop a single model using patients with partial and unknown reperfusion, then fine-tune it to create 2 separate models for minimal and major reperfusion; and 3) thresholding: use the current clinical method relying on apparent diffusion coefficient and time-to-maximum of the residue function maps. Models were evaluated using area under the curve, the Dice score coefficient, and lesion volume difference.

RESULTS

Two hundred thirty-seven patients were included (minimal, major, partial, and unknown reperfusion: n = 52, 80, 57, and 48, respectively). The pretraining approach achieved the highest median Dice score coefficient (tissue at risk = 0.60, interquartile range, 0.43-0.70; core = 0.57, interquartile range, 0.30-0.69). This was higher than the separate approach (tissue at risk = 0.55; interquartile range, 0.41-0.69; P = .01; core = 0.49; interquartile range, 0.35-0.66; P = .04) or thresholding (tissue at risk = 0.56; interquartile range, 0.42-0.65; P = .008; core = 0.46; interquartile range, 0.16-0.54; P < .001).

CONCLUSIONS

Deep learning models with fine-tuning lead to better performance for predicting tissue at risk and ischemic core, outperforming conventional thresholding methods.

High prevalence of comorbidities and use of concomitant medication in treated people living with HIV in Germany - results of the BESIDE study

Due to demographic changes in people living with HIV (PLHIV), physicians are challenged with age-related comorbidities and their management. In the absence of comprehensive data collection, the burden of comorbidities and co-medication in addition to antiretroviral therapy (ART) remains unclear for the German real-world setting. BESIDE was an observational, cross-sectional study evaluating the prevalence of comorbidities and use of co-medication in treated PLHIV. Regional distribution of study centers (n = 20), consecutive patient recruitment, and age-stratified sampling in alignment with national epidemiologic data aimed to ensure a representative sample (n = 453). The overall prevalence of comorbidities was 91.2%; 31.6% of patients had ≥4 comorbidities. The most common diagnoses were vitamin D deficiency (29.1%), depressive episode (27.8%), arterial hypertension (16.3%), and hypercholesterolemia (10.8%). 83.7% of patients were on co-medication; 21.2% taking ≥4 medications. The most common medications or supplements were vitamins (31.6%), anti-inflammatory agents (16.1%), renin-angiotensin system agents (12.1%), acid suppressants (11.7%), lipid modifying agents (10.8%); 1.3% of patients were on co-medication that should not be co-administered with ART, 41.5% on co-medication with potential for drug-drug interactions. The prevalence of comorbidities and use of co-medication among treated PLHIV in Germany is consistently high and increases across age groups, illustrating the complexity of HIV care involving appropriate ART selection.

A versatile Johansson-type tender x-ray emission spectrometer

We present a high energy resolution x-ray spectrometer for the tender x-ray regime (1.6-5.0 keV) that was designed and operated at Stanford Synchrotron Radiation Lightsource. The instrument is developed on a Rowland geometry (500 mm of radius) using cylindrically bent Johansson analyzers and a position sensitive detector. By placing the sample inside the Rowland circle, the spectrometer operates in an energy-dispersive mode with a subnatural line-width energy resolution (∼0.32 eV at 2400 eV), even when an extended incident x-ray beam is used across a wide range of diffraction angles (∼30° to 65°). The spectrometer is enclosed in a vacuum chamber, and a sample chamber with independent ambient conditions is introduced to enable a versatile and fast-access sample environment (e.g., solid/gas/liquid samples, in situ cells, and radioactive materials). The design, capabilities, and performance are presented and discussed.

Single-nucleotide polymorphisms for matrix metalloprotease-1 can affect perimysial strength and intramuscular fat content but not growth rate of cattle

Context Single-nucleotide polymorphisms (SNPs) in the gene coding for matrix metalloprotease-1 (MMP-1) are known to affect the level of intramuscular fat found in cattle. As well as a signalling molecule affecting adipogenesis, MMP-1 is a major collagenase involved in the turnover of connective tissue. Aims The aim of the work was to assess whether SNPs in the gene for MMP-1 may affect the mechanical properties of intramuscular connective tissue, and therefore meat texture. Methods Allelic frequencies of three SNPs for MMP-1 were determined in a group of black Aberdeen Angus cattle whose growth characteristics had been traced for 450 days before slaughter. Associations between the alleles of each of the three SNPs and growth rate, killing out percentage, half-carcass weight, intramuscular fat content, cooking loss, strength of perimysium in cooked M. semitendinosus and Warner–Bratzler peak force of cooked M. longissimus dorsi were studied. Key results None of the SNPs studied had any effect on growth curves, and only one SNP (ss77831914) showed differences in half-carcass weight between alleles. Carcass yield and killing out percentage showed a small difference between alleles of ss7783924. No effects were found on the Warner–Bratzler peak force of M. longissimus dorsi cooked to 70°C. Two SNPs (ss77831914 and ss77831924) showed significant differences between alleles in the raw strength of perimysium in M. semitendinosus and the amount of intramuscular fat. Conclusions Commonly occurring SNPs of the major collagenase MMP-1 can affect the strength of intramuscular connective tissue as well as intramuscular fat content. Although these differences in connective tissue strength do not influence Warner–Bratzler measures of toughness at a cooking temperature of 70°C, they may contribute to differences in toughness in low-temperature, long-time cooking. Implications Because none of the SNPs had effects on the growth curves of the cattle studied, selection of animals with the relevant alleles of SNPs ss77831914 ss77831924 could be used to produce more tender meat without affecting carcass yield.

P3812The economic burden of heart failure in Denmark from 1998 to 2016

Background

Heart failure (HF) imposes a large burden on the individual as well as society and the aim of this study was to investigate the economic burden attributed to direct and indirect costs of patients with HF before, at, and after time of diagnosis.

Methods

Using Danish nationwide registries we identified all patients >18 years with a first-time diagnosis of HF from 1998–2016 and matched them 1:1 with a control group from the background population on age, gender, marital status, and educational level. The economic analysis of the total costs after diagnosis was based on direct costs including hospitalization, procedures, medication, and indirect costs including social welfare and lost productivity to estimate the annual cost of HF.

Results

We included a total of 176,067 HF patients with a median age of 76 years, and 55% were male. Patients with HF incurred an average of €17,039 in sum of total annual direct (€11,926) and indirect (€5,113) health-care costs peaking at year of diagnosis compared to €5,936 in the control group with the majorityattributable to inpatient admissions. The total annual net costs including social transfer after index HF were €11,957 higher in patients with HF compared to controls and the economic consequences increased markedly 2 years prior to the diagnosis of HF (Figure 1).

Conclusion

Patients with HF impose significantly higher total annual health-care costs compared to a matched control group with findings evident more than 2 years prior to HF diagnosis

Acknowledgement/Funding

Novartis

Alberta Stroke Program Early CT Score Versus Computed Tomographic Perfusion to Predict Functional Outcome After Successful Reperfusion in Acute Ischemic Stroke

Background and Purpose- We aimed to compare the ability of conventional Alberta Stroke Program Early CT Score (ASPECTS), automated ASPECTS, and ischemic core volume on computed tomographic perfusion to predict clinical outcome in ischemic stroke because of large vessel occlusion ≤18 hours after symptom onset. Methods- We selected patients with acute ischemic stroke from the CRISP study (Computed Tomographic Perfusion to Predict Response to Recanalization in Ischemic Stroke Project) with successful reperfusion (modified treatment in cerebral ischemia score 2b or 3). We used e-ASPECTS software to calculate automated ASPECTS and RAPID software to estimate ischemic core volumes. We studied associations between these imaging characteristics and good outcome (modified Rankin Scale score, 0-2) or poor outcome (modified Rankin Scale score, 4-6) in univariable and multivariable analysis, after adjustment for relevant clinical confounders. Results- We included 156 patients. Conventional and automated ASPECTS was not associated with good or poor outcome in univariable analysis ( P=nonsignificant for all). Automated ASPECTS was associated with good outcome in multivariable analysis ( P=0.02) but not with poor outcome. Ischemic core volume was associated with good ( P<0.01) and poor outcome ( P=0.04) in univariable and multivariable analysis ( P=0.03 and P=0.02, respectively). Computed tomographic perfusion predicted good outcome with an area under the curve of 0.62 (95% CI, 0.53-0.71) and optimal cutoff core volume of 15 mL. Conclusions- Ischemic core volume assessed on computed tomographic perfusion is a predictor of clinical outcome among patients in whom endovascular reperfusion is achieved ≤18 hours after symptom onset. In this population, conventional or automated ASPECTS did not predict outcome.

Intensive care doctors' preferences for arterial oxygen tension levels in mechanically ventilated patients

BACKGROUND

Oxygen is liberally administered in intensive care units (ICUs). Nevertheless, ICU doctors' preferences for supplementing oxygen are inadequately described. The aim was to identify ICU doctors' preferences for arterial oxygenation levels in mechanically ventilated adult ICU patients.

METHODS

In April to August 2016, an online multiple-choice 17-part-questionnaire was distributed to 1080 ICU doctors in seven Northern European countries. Repeated reminder e-mails were sent. The study ended in October 2016.

RESULTS

The response rate was 63%. When evaluating oxygenation 52% of respondents rated arterial oxygen tension (PaO₂ ) the most important parameter; 24% a combination of PaO₂ and arterial oxygen saturation (SaO₂ ); and 23% preferred SaO₂ . Increasing, decreasing or not changing a default fraction of inspired oxygen of 0.50 showed preferences for a PaO₂ around 8 kPa in patients with chronic obstructive pulmonary disease, a PaO₂ around 10 kPa in patients with healthy lungs, acute respiratory distress syndrome or sepsis, and a PaO₂ around 12 kPa in patients with cardiac or cerebral ischaemia. Eighty per cent would accept a PaO₂ of 8 kPa or lower and 77% would accept a PaO₂ of 12 kPa or higher in a clinical trial of oxygenation targets.

CONCLUSION

Intensive care unit doctors preferred PaO₂ to SaO₂ in monitoring oxygen treatment when peripheral oxygen saturation was not included in the question. The identification of PaO₂ as the preferred target and the thorough clarification of preferences are important when ascertaining optimal oxygenation targets. In particular when designing future clinical trials of higher vs lower oxygenation targets in ICU patients.

Reviewing research priorities in weed ecology, evolution and management: a horizon scan

Weedy plants pose a major threat to food security, biodiversity, ecosystem services and consequently to human health and wellbeing. However, many currently used weed management approaches are increasingly unsustainable. To address this knowledge and practice gap, in June 2014, 35 weed and invasion ecologists, weed scientists, evolutionary biologists and social scientists convened a workshop to explore current and future perspectives and approaches in weed ecology and management. A horizon scanning exercise ranked a list of 124 pre-submitted questions to identify a priority list of 30 questions. These questions are discussed under seven themed headings that represent areas for renewed and emerging focus for the disciplines of weed research and practice. The themed areas considered the need for transdisciplinarity, increased adoption of integrated weed management and agroecological approaches, better understanding of weed evolution, climate change, weed invasiveness and finally, disciplinary challenges for weed science. Almost all the challenges identified rested on the need for continued efforts to diversify and integrate agroecological, socio-economic and technological approaches in weed management. These challenges are not newly conceived, though their continued prominence as research priorities highlights an ongoing intransigence that must be addressed through a more system-oriented and transdisciplinary research agenda that seeks an embedded integration of public and private research approaches. This horizon scanning exercise thus set out the building blocks needed for future weed management research and practice; however, the challenge ahead is to identify effective ways in which sufficient research and implementation efforts can be directed towards these needs.

Out-of-hours intensive care unit admission and 90-day mortality: a Danish nationwide cohort study

BACKGROUND

Mortality rates in critically ill adult patients admitted to the intensive care unit (ICU) remains high, and numerous patient- and disease-related adverse prognostic factors have been identified. In recent years, studies in a variety of emergency conditions suggested that outcome is dependent on the time of hospital admission. The importance of out-of-hours admission to the ICU has been sparsely evaluated and with ambiguous findings. We assessed the association between out-of-hours (16:00 to 07:00) and weekend admission to the ICU, respectively, and 90-day mortality in a nationwide cohort.

METHODS

We included all Danish adult patients admitted to the ICU between 1 January 2011 and 30 June 2014, with an ICU stay > 24 h. The crude and adjusted association between out-of-hours and weekend admission and 90-day mortality was assessed (odds ratio (ORs) with 95% confidence intervals (CI)).

RESULTS

A total of 44,797 patients were included, 53.3% were admitted out-of-hours, and 22.6% during weekends. Median age was 67 years (interquartile range (IQR) 55-76), and median SAPS II was 42 (IQR 30-54). Patients admitted in-hours vs. out-of-hours displayed a 90-day mortality rate of 41.0% vs. 44.2%. The adjusted association (OR with 95% CI) between out-of-hours admission and 90-day mortality was 1.07 (1.02-1.11), and the adjusted association (OR with 95% CI) between weekend admission and 90-day mortality was 1.10 (1.05-1.15).

CONCLUSION

This nationwide study suggests that critically ill adult patients admitted to the ICU during weekends and out-of-hours, and with an ICU stay > 24 h are at slightly increased risk of mortality.

High efficacy of sofosbuvir/velpatasvir and impact of baseline resistance-associated substitutions in hepatitis C genotype 3 infection

BACKGROUND

Twelve weeks of the pangenotypic direct-acting antiviral (DAA) combination sofosbuvir/velpatasvir (SOF/VEL) was highly efficient in patients with hepatitis C virus (HCV) genotype 3 (GT3) infection in the ASTRAL-3 approval study. However, presence of resistance-associated substitutions (RASs) in the HCV nonstructural protein 5A (NS5A) was associated with lower treatment response.

AIM

To assess the efficacy and safety of SOF/VEL ± ribavirin (RBV) and the impact of NS5A RASs and RBV use on treatment outcome in HCV GT3 infection in a real-world setting.

METHODS

In this multicentre cohort study, GT3 patients from ten treatment centres across Germany were included. Sustained virological response was assessed 12 weeks after end-of-treatment (SVR12) in modified intention-to-treat (mITT) and per-protocol analysis (PP). NS5A RASs were tested by population-based sequencing.

RESULTS

A total of 293 GT3 patients were included. The median age was 48 years, 70% were male, 25.3% were cirrhotic, 9.2% were HCV/HIV co-infected and 21.8% were treatment-experienced, including 4.1% with DAA experience. Baseline NS5A RASs (Y93H, A30K, L31M) were detected in 11.2%. RBV was added in 5% of noncirrhotic and 58.9% of cirrhotic patients, respectively. SVR12 rates for SOF/VEL±RBV were 95.9% (mITT) and 99.5% (PP), respectively. Only 1 virological relapse occurred in a cirrhotic patient previously treated with SOF/RBV. No treatment-related major adverse events occurred.

CONCLUSION

Twelve weeks of SOL/VEL±RBV was safe and highly efficient in HCV GT3 across a diverse patient population. Baseline NS5A RASs were rarely observed and presence did not seem to impact SVR, regardless of the use of RBV.

Attitudes of physicians towards the care of critically ill elderly patients - a European survey

BACKGROUND

Very elderly patients are one of the fastest growing population in ICUs worldwide. There are lots of controversies regarding admission, discharge of critically ill elderly patients, and also on treatment intensity during the ICU stay. As a consequence, practices vary considerably from one ICU to another. In that perspective, we collected opinions of experienced ICU physicians across Europe on statements focusing on patients older than 80.

METHODS

We sent an online questionnaire to the coordinator ICU physician of all participating ICUs of an recent European, observational study of Very old critically Ill Patients (VIP1 study). This questionnaire contained 12 statements about admission, triage, treatment and discharge of patients older than 80.

RESULTS

We received answers from 162 ICUs (52% of VIP1-study) spanning 20 different European countries. There were major disagreements between ICUs. Responders disagree that: there is clear evidence that ICU admission is beneficial (37%); seeking relatives' opinion is mandatory (17%); written triage guidelines must be available either at the hospital or ICU level (20%); level of care should be reduced (25%); a consultation of a geriatrician should be sought (34%) and a geriatrician should be part of the post-ICU trail (11%). The percentage of disagreement varies between statements and European regions.

CONCLUSION

There are major differences in the attitude of European ICU physicians on the admission, triage and treatment policies of patients older than 80 emphasizing the lack of consensus and poor level of evidence for most of the statements and outlining the need for future interventional studies.

Improving handover between the transport team and neonatal intensive care unit staff in neonatal transports using the plan-do-study-act tool

OBJECTIVES

The aim was to achieve 100% effective handover from the critical care transport team to the neonatal intensive care unit (NICU) medical team.

STUDY DESIGN

All patients transferred from referring hospitals by the critical care transport team to the Level IV NICU were included. Data for each infant was collected prospectively. The percentage of transported patients for which medical team and nursing handover occurred was recorded. A quality improvement project was launched using the Plan-Do-Study-Act (PDSA) tool. We implemented several processes including call from the transport team before arrival and the completion of a transfer of care form on arrival to the NICU. The process measures and the outcome measure of completion of handover were monitored. Run charts of process measures and the outcome measure were analyzed.

RESULTS

Completion of medical handover increased from 95% (baseline) to 100% after 3 PDSA cycles and this has been maintained for 18 consecutive months.

CONCLUSION

Medical handover from the critical care transport team to the NICU medical staff has been achieved and sustained for all neonatal transports.

Real-world experience with the all-oral, interferon-free regimen of ombitasvir/paritaprevir/ritonavir and dasabuvir for the treatment of chronic hepatitis C virus infection in the German Hepatitis C Registry

Real-world studies are relevant to complement clinical trials on novel antiviral therapies against chronic hepatitis C; however, clinical practice data are currently limited. This study investigated effectiveness and safety of ombitasvir/paritaprevir/ritonavir (OBV/PTV/r)±dasabuvir (DSV)±ribavirin (RBV) for treatment of HCV genotype (GT) 1 and GT4 infection in a large real-world cohort. The German Hepatitis C Registry is an observational cohort study prospectively collecting clinical practice data on direct-acting antiviral therapies. Patients with GT1/4 infection treated with OBV/PTV/r±DSV±RBV were analysed. Effectiveness was assessed by sustained virologic response in 558 patients who reached post-treatment week 12 (SVR12). Safety is reported in 1017 patients who initiated treatment. Of the patients, 892 (88%) had GT1 and 125 (12%) had GT4 infection. Prior treatment experience and cirrhosis were reported in 598 (59%) and 228 (22%) patients, respectively. Overall, SVR12 (mITT) was 96% (486/505) in GT1- and 100% (53/53) in GT4 patients. SVR12 rates were high across subgroups including patients with cirrhosis (95%, 123/129), patients with moderate to severe renal impairment (100%, 34/34), and subgroups excluded from registrational trials like patients ≥70 years (96%, 64/67) and failures to prior protease inhibitor treatment (96%, 46/48). Adverse events (AEs) and serious AEs were reported in 52% (525/1017) and 2% (21/1017) of patients, respectively, and led to treatment discontinuation in 1.5% (15/1017) of patients. OBV/PTV/r±DSV±RBV was effective and generally well tolerated for treatment of HCV infection in clinical practice.

Extracorporeal cardiopulmonary resuscitation after out-of-hospital cardiac arrest in a Danish health region

BACKGROUND

Extracorporeal Cardiopulmonary Resuscitation (ECPR) has emerged as a feasible rescue therapy for refractory, normothermic out-of-hospital cardiac arrest (OHCA). Reported survival rates vary and comparison between studies is hampered by heterogeneous study populations, differences in bystander intervention and in pre-hospital emergency service organisation. We aimed to describe the first experiences, treatment details, complications and outcome with ECPR for OHCA in a Danish health region.

METHODS

Retrospective study of adult patients admitted at Aarhus University Hospital, Denmark between 1 January 2011 and 1 July 2015 with witnessed, refractory, normothermic OHCA treated with ECPR. OHCA was managed with pre-hospital advanced airway management and mechanical chest compression during transport. Relevant pre-hospital and in-hospital data were collected with special focus on low-flow time and ECPR duration. Survival to hospital discharge with Cerebral Performance Category (CPC) of 1 and 2 at hospital discharge was the primary endpoint.

RESULTS

Twenty-one patients were included. Median pre-hospital low-flow time was 54 min [range 5-100] and median total low-flow time was 121 min [range 55-192]. Seven patients survived (33%). Survivors had a CPC score of 1 or 2 at hospital discharge. Five survivors had a shockable initial rhythm. In all survivors coronary occlusion was the presumed cause of cardiac arrest.

CONCLUSION

Extracorporeal cardiopulmonary resuscitation is feasible as a rescue therapy in normothermic refractory OHCA in highly selected patients. Low-flow time was longer than previously reported. Survival with favourable neurological outcome is possible despite prolonged low-flow duration.

Abstract WMP16: Relative Dwi Signal Intensity as a Predictor of Stroke Onset Time Compared to the Visual DWI/FLAIR Mismatch

Introduction: The DWI/FLAIR mismatch has been proposed as an imaging pattern to predict stroke onset before 4.5h in patients with unknown time of symptom duration. Limitations of the DWI/FLAIR mismatch include the additional imaging time required to obtain FLAIR, difficulty of assessment in patients with severe white matter disease, poor interrater agreement, and motion sensitivity of longer MRI sequences. We hypothesised that automated analysis of DWI imaging would be at least as accurate to predict stroke onset before 4.5h.

Methods: Data from the Axis 2 trial were used and patients were included in whom a DWI lesion was detected by automated software (RAPID). The visual DWI/FLAIR mismatch was rated in accordance with the criteria of the ongoing WAKE-UP trial. For every patient the relative DWI (rDWI) was calculated in a voxel based manner as the ratio of the diffusion intensity in that voxel and the median diffusion intensity of a sphere with radius 15 mm around the homologue voxel in the contralateral hemisphere. The mean and standard deviation (SD) of the rDWI was obtained in the DWI lesion. Receiver operating curves (ROC) and corresponding area under the curves (AUC) for predicting the 4.5h time-window were determined.

Results: We included 200 patients. In 8 patients (4%) the visual DWI/FLAIR rating was hampered due to either extensive white matter disease or poor quality of FLAIR imaging. The DWI/FLAIR mismatch had an AUC of 0.66 to predict stroke onset before 4.5h vs an AUC of 0.71 for rDWI SD (p for difference=0.4). The optimal rDWI SD threshold for predicting stroke ≤ 4.5h was 0.23. Using this threshold, stroke onset was accurately predicted in 73% of patients vs 65% accuracy with the visual DWI/FLAIR mismatch (p for difference=0.1). (table 1)

Conclusion: Our results suggest that rDWI may have advantages over the visual DWI/FLAIR mismatch for predicting the time of stroke onset. rDWI provides an accurate and objective assessment with the potential for fully automated processing.

Chronic hepatitis C patients prior to broad access to interferon-free treatments in Germany

In 2014, the first interferon-free treatment options for chronic Hepatitis C (CHC) became available in Europe introducing a new era of highly effective and well tolerated oral treatment options for CHC. The data from the cross-sectional study CURRENT-C highlights the epidemiological characteristics of patients with CHC in Germany. During the period that the study was conducted, the approval of the combination drugs for the treatment of CHC was imminent.Between June and November 2014, 1471 CHC-patients not receiving anti-HCV treatment were included nationwide in 40 German centers specializing in viral hepatitis. The mean age was 52.4 years with 41.2 % of the patients being female. Presumed route of infection in male patients was most frequently drug use (46.2 %) and blood products in females (22.8 %). The route of infection was unknown in 28.2 % of male and 43.1 % of female patients. Compared to male patients, female patients were older (55.6 vs. 50.1 years) and longer diagnosed with HCV (18 vs. 15 years). First language of the patients was most frequently German (72.2 %), followed by Russian (14.2 %), and Polish (2.9 %). HCV genotype (GT) 1 was found in 73.8 % (1a 29.0 %, 1b 38.4 %), GT2 in 3.5 %, GT3 in 18.3 %, GT4 in 4.2 %, GT5 in 0.2 %, and GT6 in 0.3 %. Liver cirrhosis was diagnosed in 15.7 % of the patients (17.1 % male, 13.7 % female). 43.2 % of the patients had already received HCV treatment, most frequently dual therapy with pegIFN + RBV (75.8 %) or triple therapy with telaprevir or boceprevir (20.3 %). Compared to treatment-naïve patients, pretreated HCV patients were older (55.1 vs. 50.3 years) and more frequently had liver cirrhosis as clinical diagnosis (22.2 % vs. 10.8 %). Patients scheduled for HCV treatment within the next 3 months had higher rates of pre-treatment (49.4 % vs. 37.0 %), and liver cirrhosis (21.4 % vs. 10.0 %).Compared to epidemiological data of Hüppe et al. 1 from 2003 to 2006, Klass et al. 2 stated in 2012 in a comparable setting that the German CHC population were older and had more advanced liver disease. The current data seem to support this ongoing trend towards more difficult to treat patients with an urgent need for new treatment options.

No Benefit in Seeing a Dark Future?

Abstract. In their article, Lang, Weiss, Gerstorf, & Wagner, (2013) use the adult life span sample of the national German Socio-Economic Panel (GSOEP) to explore functional outcomes of life satisfaction with regard to hazards of mortality. Their findings suggest that “being overly optimistic [in] predicting a better future than actually observed was associated with […] a great risk of mortality within the following decade.” In this short paper, we analyze the same data set using the same model, but, in addition to the self-rated health status in the starting year included in the model by Lang et al. (2013) , we furthermore control for the self-rated health at the target year. With this modification, it turns out that the accuracy of anticipated future life satisfaction has no significant effect on mortality. Two additional analyses underpin this finding.

The antinociceptive efficacy of buprenorphine administered through the drinking water of rats

Postoperative pain management in laboratory animals is important for animal welfare and required under law in many countries. Frequent injection of analgesics to rodents after surgery is stressful for the animals and labour-intensive for animal care personnel. An alternative dosing scheme such as administration of analgesics in the drinking water would be desirable. However, the efficacy of a chronic oral analgesic treatment via this route has not yet been documented. This study investigated the antinociceptive efficacy of buprenorphine administered ad libitum via the drinking water of laboratory rats. The antinociceptive efficacy of buprenorphine in drinking water was compared with repeated subcutaneous injections. A comparison was also made between buprenorphine in drinking water and the combination of one single subcutaneous injection of buprenorphine followed by buprenorphine in drinking water. Antinociception was assessed by use of an analgesiometric model measuring the rats' latency time to withdrawal from a noxious heat stimulus applied to the plantar surface of the paw. Results revealed that buprenorphine in drinking water (0.056 mg/mL) induced significant increases in paw withdrawal latency times during a three-day period of administration with a maximal effect at 39 h after the start of buprenorphine administration. One single injection of buprenorphine (0.1 mg/kg s.c.) followed by buprenorphine in the drinking water (0.056 mg/mL) induced an earlier onset of antinociception than buprenorphine in drinking water alone. In contrast, buprenorphine (0.1 mg/kg s.c.) injected every 8 h over a period of three days did not result in significant increases in paw withdrawal latency times. In conclusion, our results suggest that one single subcutaneous injection of buprenorphine followed by buprenorphine in drinking water may be a viable treatment option for the relief of pain in laboratory rats, but at the doses used in this study in pain-free rats it was associated with a decrease in water intake and some behavioural changes.

Phase-Type Distributions and Optimal Stopping for Autoregressive Processes

Autoregressive processes are intensively studied in statistics and other fields of applied stochastics. For many applications, the overshoot and the threshold time are of special interest. When the upward innovations are in the class of phase-type distributions, we determine the joint distribution of these two quantities and apply this result to problems of optimal stopping. Using a principle of continuous fit, this leads to explicit solutions.