Compositionally Equivariant Representation Learning

Deep learning models often need sufficient supervision (i.e. labelled data) in order to be trained effectively. By contrast, humans can swiftly learn to identify important anatomy in medical images like MRI and CT scans, with minimal guidance. This recognition capability easily generalises to new images from different medical facilities and to new tasks in different settings. This rapid and generalisable learning ability is largely due to the compositional structure of image patterns in the human brain, which are not well represented in current medical models. In this paper, we study the utilisation of compositionality in learning more interpretable and generalisable representations for medical image segmentation. Overall, we propose that the underlying generative factors that are used to generate the medical images satisfy compositional equivariance property, where each factor is compositional (e.g. corresponds to human anatomy) and also equivariant to the task. Hence, a good representation that approximates well the ground truth factor has to be compositionally equivariant. By modelling the compositional representations with learnable von-Mises-Fisher (vMF) kernels, we explore how different design and learning biases can be used to enforce the representations to be more compositionally equivariant under un-, weakly-, and semi-supervised settings. Extensive results show that our methods achieve the best performance over several strong baselines on the task of semi-supervised domain-generalised medical image segmentation. Code will be made publicly available upon acceptance at https://github.com/vios-s.

The role of noise in denoising models for anomaly detection in medical images

Pathological brain lesions exhibit diverse appearance in brain images, in terms of intensity, texture, shape, size, and location. Comprehensive sets of data and annotations are difficult to acquire. Therefore, unsupervised anomaly detection approaches have been proposed using only normal data for training, with the aim of detecting outlier anomalous voxels at test time. Denoising methods, for instance classical denoising autoencoders (DAEs) and more recently emerging diffusion models, are a promising approach, however naive application of pixelwise noise leads to poor anomaly detection performance. We show that optimization of the spatial resolution and magnitude of the noise improves the performance of different model training regimes, with similar noise parameter adjustments giving good performance for both DAEs and diffusion models. Visual inspection of the reconstructions suggests that the training noise influences the trade-off between the extent of the detail that is reconstructed and the extent of erasure of anomalies, both of which contribute to better anomaly detection performance. We validate our findings on two real-world datasets (tumor detection in brain MRI and hemorrhage/ischemia/tumor detection in brain CT), showing good detection on diverse anomaly appearances. Overall, we find that a DAE trained with coarse noise is a fast and simple method that gives state-of-the-art accuracy. Diffusion models applied to anomaly detection are as yet in their infancy and provide a promising avenue for further research. Code for our DAE model and coarse noise is provided at: https://github.com/AntanasKascenas/DenoisingAE.

Adversarial counterfactual augmentation: application in Alzheimer's disease classification

Due to the limited availability of medical data, deep learning approaches for medical image analysis tend to generalise poorly to unseen data. Augmenting data during training with random transformations has been shown to help and became a ubiquitous technique for training neural networks. Here, we propose a novel adversarial counterfactual augmentation scheme that aims at finding the most effective synthesised images to improve downstream tasks, given a pre-trained generative model. Specifically, we construct an adversarial game where we update the input conditional factor of the generator and the downstream classifier with gradient backpropagation alternatively and iteratively. This can be viewed as finding the 'weakness' of the classifier and purposely forcing it to overcome its weakness via the generative model. To demonstrate the effectiveness of the proposed approach, we validate the method with the classification of Alzheimer's Disease (AD) as a downstream task. The pre-trained generative model synthesises brain images using age as conditional factor. Extensive experiments and ablation studies have been performed to show that the proposed approach improves classification performance and has potential to alleviate spurious correlations and catastrophic forgetting. Code: https://github.com/xiat0616/adversarial_counterfactual_augmentation.

Three dimensional modelling of mutant Kir2.1 channel PIP2 interactions help stratify arrhythmia severity in Andersen Tawil syndrome type 1

Background

Andersen-Tawil type 1 (ATS1) is associated with loss-of-function mutations in the inward rectifier potassium channel Kir2.1, which controls cardiac excitability and impulse conduction. Phosphatidylinositol-4,5-bisphosphate (PIP2) acts as an essential cofactor regulating the opening of Kir2.1 channels. Fifty percent of reported ATS1 mutations affect Kir2.1-PIP2 interactions, leading to ECG defects, ventricular arrhythmias and sudden cardiac death (SCD) by mechanisms that are poorly understood.

Purpose

To test the hypothesis that the degree of arrhythmogenic severity of ATS1 mutations disrupting PIP2-Kir2.1 binding may be predicted by the level of polarization of the mutant Kir2.1 channel pore.

Methods

We first used a statistical mean value approach to classify the 40 known arrhythmogenic ATS1 mutations impacting Kir2.1-PIP2 interaction (N=260 individuals) according to arrhythmogenic severity, ranging from SCD through ventricular bigeminy and QT prolongation. We then generated 3D in-silico atomic models of the wildtype channel and the 10 mutant channels with the most severe arrhythmic phenotype to assess the mechanism of the structural defects associated with Kir2.1-PIP2 disruption.

Results

Our cardiac lethality scoring stratifying Kir2.1 mutations according to arrhythmogenic severity was validated by three additional biostatical quantitative measures. On in-silico modelling, wildtype Kir2.1 channels without PIP2 binding had transmembrane and cytoplasmic pore radius of 1.5 and 3 Å, respectively. Kir2.1-PIP2 interactions increased transmembrane and cytoplasmic pore radius to 3 and 6 Å, respectively. All 10 Kir2.1 mutations had similar transmembrane and cytoplasmic pore radius of ∼1.0 and ∼3.0 Å, respectively. The most severe mutations yielded pore channels with highly polarized electrostatic forces. Remarkably, simulations showed a descending electrostatic pattern at the transmembrane region of PIP2 binding, where the more severe the mutation, the more positive that region was. Structural changes produced by mutations correlated with cardiac severity (R2=0.51; p<0.005) in that the most drastically altered protein structure correlated with the most severe arrhythmic phenotype.

Conclusions

Computer simulations of mutant Kir2.1 channel structure from the most arrhythmogenic to the least arrhythmogenic predict a gradual decrease in polarization of electrostatic forces along the Kir2.1 channel pore. The results reveal a novel mechanistic stratification of arrhythmogenic severity of ATS1 mutant Kir2.1 channel-PIP2 interactions and open new pathways for developing more personalized ATS1 patient therapies.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): La Caixa Banking Foundation under the project code HR18-00304Fundaciόn La Marato TV3: Ayudas a la investigaciόn en enfermedades raras 2020

Cardiac aging synthesis from cross-sectional data with conditional generative adversarial networks

Age has important implications for health, and understanding how age manifests in the human body is the first step for a potential intervention. This becomes especially important for cardiac health, since age is the main risk factor for development of cardiovascular disease. Data-driven modeling of age progression has been conducted successfully in diverse applications such as face or brain aging. While longitudinal data is the preferred option for training deep learning models, collecting such a dataset is usually very costly, especially in medical imaging. In this work, a conditional generative adversarial network is proposed to synthesize older and younger versions of a heart scan by using only cross-sectional data. We train our model with more than 14,000 different scans from the UK Biobank. The induced modifications focused mainly on the interventricular septum and the aorta, which is consistent with the existing literature in cardiac aging. We evaluate the results by measuring image quality, the mean absolute error for predicted age using a pre-trained regressor, and demonstrate the application of synthetic data for counter-balancing biased datasets. The results suggest that the proposed approach is able to model realistic changes in the heart using only cross-sectional data and that these data can be used to correct age bias in a dataset.

Causal machine learning for healthcare and precision medicine

Causal machine learning (CML) has experienced increasing popularity in healthcare. Beyond the inherent capabilities of adding domain knowledge into learning systems, CML provides a complete toolset for investigating how a system would react to an intervention (e.g. outcome given a treatment). Quantifying effects of interventions allows actionable decisions to be made while maintaining robustness in the presence of confounders. Here, we explore how causal inference can be incorporated into different aspects of clinical decision support systems by using recent advances in machine learning. Throughout this paper, we use Alzheimer's disease to create examples for illustrating how CML can be advantageous in clinical scenarios. Furthermore, we discuss important challenges present in healthcare applications such as processing high-dimensional and unstructured data, generalization to out-of-distribution samples and temporal relationships, that despite the great effort from the research community remain to be solved. Finally, we review lines of research within causal representation learning, causal discovery and causal reasoning which offer the potential towards addressing the aforementioned challenges.

Learning disentangled representations in the imaging domain

Disentangled representation learning has been proposed as an approach to learning general representations even in the absence of, or with limited, supervision. A good general representation can be fine-tuned for new target tasks using modest amounts of data, or used directly in unseen domains achieving remarkable performance in the corresponding task. This alleviation of the data and annotation requirements offers tantalising prospects for applications in computer vision and healthcare. In this tutorial paper, we motivate the need for disentangled representations, revisit key concepts, and describe practical building blocks and criteria for learning such representations. We survey applications in medical imaging emphasising choices made in exemplar key works, and then discuss links to computer vision applications. We conclude by presenting limitations, challenges, and opportunities.

Effects of concurrent training on cardiorespiratory fitness and body composition in adults with schizophrenia: CORTEX-SP study

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Spanish Ministry of Economy and Competitiveness “Fondo de Investigación Sanitaria del Insti-tuto de Salud Carlos III”

Background

Concurrent training (i.e. a combination of aerobic and resistance exercise in the same session) is emerging as a time-efficient exercise strategy for improving cardiorespiratory fitness and controlling body composition parameters.

Purpose

The purpose of this study was to determine the effectiveness of a concurrent exercise program on cardiorespiratory fitness and body composition in adults with schizophrenia (SP).

Methods

Participants (n=98, 20.4% women, 41.4±10.1 yr old) with SP were randomly assigned into an attention control group (usual care) or a supervised exercise group (concurrent training, 3 days/week). All variables were assessed pre- and post-intervention (20 weeks). For the assessment of cardiorespiratory fitness, a peak cardiopulmonary exercise test on a cycle ergometer and the Modified Shuttle Walk Test (MSWT) were used.

Results

Following the intervention, in the control group, there was a significant (P <0.05) increased in body mass (Δ = 2.54%), body mass index, BMI (Δ = 2.82%), waist circumference (Δ = 2.70%) and a decreased in MSWT (Δ = - 7.54%). However, in the exercise group, there was a significant (P<0.001) increased in first ventilatory threshold, VT1 (Δ = 28.69%), peak oxygen uptake, V̇O2peak (L∙min-1) (Δ = 19.58%), V̇O2peak (mL∙kg.1∙min-1) (Δ = 21.52%) and MSWT-distance (Δ = 11.43%), with no significant changes in body composition (P>0.05). When both groups were compared, body mass, and BMI was significantly (P<0.05) more reduced, and VT1, V̇O2peak, and MSWT more increased in the exercise group.

Conclusion

A supervised concurrent exercise program in people with SP helps to maintain body composition values and leads to improvements in cardiorespiratory fitness levels. Exercise should be considered as a co-adjuvant program in the treatment of population with SP.

Characterization of open woodwind toneholes by the tube reversed method

Woodwind tonehole's linear behavior is characterized by two complex quantities: the series and shunt acoustic impedances. A method to determine experimentally these two quantities is presented for the case of open toneholes. It is based on two input impedance measurements. The method can be applied to clarinet-like instruments, and can be used for undercut toneholes as well as toneholes with pads above their output, under the condition that a symmetry axis exists. The robustness of the method proposed is explored numerically through the simulation of the experiment when considering geometrical and measurement uncertainties. Experimental results confirm the relevance of the method proposed to estimate the shunt impedance. Even the effect of small changes in the hole's geometry, such as those induced by undercutting, are characterized experimentally. The main effect of undercutting is shown to be a decrease in the tonehole's acoustic mass, in agreement with theoretical considerations based on the shape of the tonehole. Investigation on the effects of pads will be studied in a further work. Experimental results also reveal that losses in toneholes are significantly higher than those predicted by the theory. Therefore, the method is suitable for the experimental determination of the shunt impedance, but it is not convenient for the characterization of the series impedance.

The Patient, Investigator, Nurse, Carer Questionnaire (PINC-Q): a cross-sectional, retrospective, non-interventional study exploring the impact of less frequent medication administration with paliperidone palmitate 3-monthly as maintenance treatment for schizophrenia

BACKGROUND

To understand the implications of switching from paliperidone palmitate 1-monthly (PP1M) to paliperidone palmitate 3-monthly (PP3M) treatment of schizophrenia from the perspective of four key stakeholders: patients, physicians, nurses and carers.

METHODS

This was a cross-sectional, retrospective, non-interventional study comprising a one-time questionnaire (PINC-Q) for adult patients (aged ≥18 years) with schizophrenia (International Classification of Diseases; ICD-10) and their physician, nurse and carer. Questionnaires were developed in association with patient and carer advocacy groups (GAMIAN and EUFAMI) and following an advisory board formed of psychiatrists and nurses. The degree of alignment between stakeholders was also examined.

RESULTS

Responses were received from a total of 224 evaluable patients. For most patients (88.4%), responses were received from at least two other stakeholders. Patients were moderately ill with mild-to-moderate lack of insight and had received PP1M for a mean (standard deviation [SD]) of 23.9 (21.28) months before switching to PP3M (duration mean [SD] 12.8 [3.72] months). The most frequently reported reasons to switch from PP1M to PP3M were 'to live life as normally as possible' and 'patient convenience'. Over 79% of responses within each stakeholder group stated that PP3M helped the patients, with increased patient activity and social involvement, improved frequency and quality of physician-patient and nurse-patient communication and decreased perceived stigma.

CONCLUSIONS

The results of this study add to the increasing body of evidence supporting the benefits of PP3M in a population of patients with schizophrenia representative of real-world clinical practice.

OP0035 ASSESSMENT OF THE INTESTINAL PERMEABILITY IN PATIENTS WITH RHEUMATOID ARTHRITIS USING COLONIC TISSUES AND SERA

Background:

Patients with rheumatoid arthritis (RA) have an altered gut microbiota (dysbiosis) (1-3). This microbiota interacts with intestinal epithelium which can lead to an increased intestinal permeability, responsible for the passage of antigens and inflammatory molecules, and can therefore promote systemic inflammation. Gut microbiota tends to normalize with disease control (2), suggesting that systemic inflammation may directly influence the composition of microbiota and the gut barrier. It was shown in many inflammatory diseases that intestinal permeability is impaired, but to date there is very little data in RA.

Objectives:

In the present study, we evaluate the intestinal permeability in RA patients by analyzing tight junctions in colonic biopsies and serum markers.

Methods:

Colonic biopsies from 20 RA patients who underwent coloscopy for screening with normal histology were compared with those from 20 age and sex matched controls. ZO-1, occludin and claudin 2 junction proteins were evaluated by immunohistochemistry. The staining intensity was assessed by two blinded independent readers. The serum concentrations of LPS-binding protein (LBP), CD14s and zonulin were evaluated by ELISA in 25 patients naive of DMARDs, 41 patients before and after introduction of a DMARDs and 21 controls. Elevated zonulin in serum indicates an increase in intestinal permeability while LBP and CD14s indicate bacterial translocation.

Results:

ZO-1 expression was significantly lower in biopsies from patients with RA than controls (mean score ± SD of 1.6 ± 0.56 vs 2.0 ± 0.43; p = 0.01). Age, sex, disease duration and immunological status did not significantly influence the expression of colonic junction proteins. LBP and CD14s were higher in serum from RA patients naive of DMARDs than controls (p = 0.002 and p = 0.003). LBP, CD14s and zonulin levels significantly correlated with DAS28 (r = 0.61, p = 0.005; r = 0.51, p = 0.030 and r = 0.46, p = 0.049, respectively). After treatment, unlike non-responders, LBP and CD14s were significantly reduced in DMARD responders and variations in LBP and CD14s significantly correlated with changes in DAS28 (r = 0.46, p = 0.002 and r = 0, 33 and p = 0.030, respectively).

Conclusion:

This work is one of the first to explore intestinal permeability in RA and to show altered tight junction in colonic tissue from RA. This increased intestinal permeability appears to be related to the systemic inflammation. Improving the gut microbiota through food or probiotics could enhance the effect of treatments by limiting this amplification loop of inflammation.

References:

[1]Horta-Baas G, Romero-Figueroa MDS, Montiel-Jarquin AJ, Pizano-Zarate ML, Garcia-Mena J, Ramirez-Duran N. Intestinal Dysbiosis and Rheumatoid Arthritis: A Link between Gut Microbiota and the Pathogenesis of Rheumatoid Arthritis. J Immunol Res. 2017;2017:4835189.

[2]Zhang X, Zhang D, Jia H, Feng Q, Wang D, Liang D, et al. The oral and gut microbiomes are perturbed in rheumatoid arthritis and partly normalized after treatment. Nat Med. 2015;21(8):895-905.

[3]Maeda Y, Kurakawa T, Umemoto E, Motooka D, Ito Y, Gotoh K, et al. Dysbiosis Contributes to Arthritis Development via Activation of Autoreactive T Cells in the Intestine. Arthritis Rheumatol. 2016;68(11):2646-61.

Disclosure of Interests:

Rachel Audo: None declared, Pauline Sanchez: None declared, Julie Mielle: None declared, Laurence Macia: None declared, Benjamin Rivière: None declared, Cédric Lukas: None declared, Bernard Combe: None declared, Jacques Morel: None declared, Claire Daien Speakers bureau: Pfizer roche chugai fresenius BMS msd Novartis galapagos, Consultant of: Abivax abbbvie BMS roche chugai, Grant/research support from: Pfizer, roche-chugai, fresenius, msd

11 Effect of breed type on production of bovine embryos: Experience in Paraguay

One of the parameters that has the most influence on invitro embryo production programs is the number of oocytes obtained in each follicular aspiration session (ovum pickup; OPU). A significant impact of the breed of the donor on this parameter has been reported. The objective of this work was to compare the parameters of an invitro embryo production program of cows of different breeds in Paraguay. A total of 4811 OPU sessions were performed between 2016 and 2019 in cows classified according to breed and type. Beef-type breeds: Nelore (Bos indicus): n=1569; Aberdeen Angus (Bos taurus): n=1276; and Brangus (Cross): n=182 OPU, and Gyr (Bos indicus): n=1086; dairy breeds: Holstein (Bos taurus): n=401, and Girolando (Cross): n=297. The oocytes were aspirated and transported to the same laboratory located in Asunción, Paraguay. The invitro embryo production protocol was similar in all types. Bull semen tested for IVF was used. The number of oocytes, percentage viability, and percentage embryo production were evaluated. Additionally, the mean and standard deviation of the variables were calculated to show the efficiency of the processes, according to the production aptitude of the donors (meat or milk) and the breed type (Bos indicus, Bos taurus, or crosses). Continuous data were analysed with ANOVA and Tukey’s post hoc comparisons. Categorical data were analysed using Chi-squared at a significance level of 0.05. In this work, the production aptitude had no significant effect over the studied variables. However, some significant differences were found considering the breed type of the oocyte donor cow, as shown in Table 1. When crosses with the pure breeds are compared with their crosses, we found that Brangus produced more pregnancies and a greater number of oocytes/OPU compared with Angus (P<0.05). When the same comparison was made between Girolando and Holstein, no significant differences were found. The results show that Bos indicus breeds and their crosses have a greater capacity to produce more oocytes and embryos and that Bos indicus and crossbreeds were more efficient in producing pregnancies (2-fold) per OPU session than Bos taurus breeds. Additionally, crossing with meat indicus breeds generates better quality embryos and increases efficiency in the system of embryo production. Table 1. Comparison of embryo production parameters Item Breed type Bos indicus Cross Bos taurus Oocytes/OPU (mean±SD) 29.8±2.7a 26.3±7.8a 14.6±1.4b Viable oocytes, % 64.7±3a 64.6±3.4a 60.1±3.1a Embryo produced/OPU, % 35.2±4.7a 32.8±9.4a 26.2±4a Embryo/OPU 6.9±1.7a 5.4±1.7a 2.3±0.4b Pregnancy rate, % 29.6±5.5a 33.1±6.3a 25.3±5a Pregnancies/OPU 2.1±0.9a 1.9±1a 0.6±0.2b a,bValues within a row different letters differ (P<0.05).

Effect of Paliperidone Palmitate 3-Month Formulation on Goal Attainment and Disability After 52 Weeks' Treatment in Patients with Clinically Stable Schizophrenia

PURPOSE

This pragmatic clinical study aimed to assess goal attainment among patients with schizophrenia treated with paliperidone palmitate 3-monthly (PP3M) and its relation to their level of disability, and whether patients achieved symptomatic remission at the study endpoint.

PATIENTS AND METHODS

Goal attainment was assessed as a secondary endpoint using Goal Attainment Scaling (GAS) within a 52-week, prospective, single-arm, non-randomized, open-label, international, multicenter study evaluating the impact of transitioning stable patients with schizophrenia from paliperidone palmitate 1-monthly (PP1M) to PP3M. Additional exploratory analyses were performed to investigate the relationship between disability and functioning as measured by the World Health Organization Disability Assessment Schedule (WHODAS), Version 2.0, symptomatic remission, and goal attainment.

RESULTS

Overall, 305 patients were enrolled, of whom 281 (92.1%) provided GAS data at baseline. Of these, 160 achieved symptomatic remission at the last observation carried forward (LOCF) endpoint. The most common category of goals was "self" related, of which work-related was most frequent. Two-thirds of patients (67.7%) achieved at least one goal at the LOCF endpoint. Goal achievement was positively associated with lower baseline symptoms and symptomatic remission at LOCF endpoint, and with lower WHODAS scores at baseline and LOCF endpoint and greater WHODAS score improvements from baseline. Age, duration of disease, and duration of PP1M treatment before the switch did not impact goal setting and goal attainment. The proportion of patients with remunerated work status increased by 11.3% at LOCF endpoint.

CONCLUSION

The results of this secondary endpoint analysis indicate that continued treatment of patients with schizophrenia with PP3M following stabilization with PP1M may facilitate attainment of patients' personal goals and reduce disability, especially, but not exclusively, in patients with symptomatic remission achieved at LOCF.

129Magnetic resonance predictors of ventricular tachycardia recurrence after radiofrequency substrate ablation: septal and transmural channels

 

Ventricular tachycardia (VT) substrate-based ablation has become a gold standard in patients with structural heart disease. Success of VT ablation is related with mortality reduction.

Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) is a powerful technique to assess substrate of VT. Myocardial fibrosis is electrically inert (Core) but it is surrounded by a ‘‘border-zone (BZ)’’ where normal cardiomyocytes intermingle with dense bundles of fibrosis. Slow impulse conduction in the BZ allows for the re-entry circuits leading to VT. Both the presence and extent of LGE have been associated with VT and SCD risk. LGE-CMR tissue characterization can be depicted as pixel signal intensity (PSI) maps and can guide VT ablation.

The aim of this study was to analyze possible VT recurrence predictors in a long term follow-up of patients that underwent VT ablation (endo and/or epicardial) related with LGE-CMR PSI maps.

We analyzed 234 consecutive patients (age: 63.2 ± 14 years, follow-up: 3.14 years ±1.8) undergoing VT ablation with scar-dechannelling technique at a single center from 2013 to 2018.  110 patients underwent a preprocedural LGE-CMR, and in 94 patients (85,5%) a CMR-aided ablation using the PSI maps was performed.

All LGE-CMR images were semi-automatically processed using a dedicated software. PSI-based algorithm was applied to characterize the hyperenhanced area as core or BZ, using fixed threshold of the maximum intensity. A LV 3D shell was obtained and were imported into the navigation system. In the PSI maps, heterogenous tissue channels were defined as a continuous corridor of BZ surrounded by scar core or an anatomic barrier that connects 2 areas of healthy tissue.

Results

Overall recurrence of VT was 41.8 %. There was ICD shock reduction, from 43,6% to a 28,2% (ICD shocks before ablation 2,23 ± 7,32, after: 1,10 ± 2,92).

Left ventricle mass predicted significantly VT recurrence (Mean 168,3 ± 53,3 vs 152,3 ± 46,4 g, HR 1,02 [1,01-1,02], p < 0.001). LGE distribuition was predictive of VT recurrence when a more than 40% of the interventricular septum was involved (62,5% vs 37,8%; HR 1,6 [1,01-1,02]; p = 0,044). No differences in recurrence were found among the patterns of LGE distribution (transmural/epicardial/subendocardial or peculiar segments localizations). The amount of BZ and the total amont of Core + BZ was related with VT recurrence (BZ 26,6 ± 13,9 vs 19,56 ± 9,69 g, HR 1,03 [1,01-1,06], p = 0,012; total Core + BZ 37,1 ± 18,2 vs 29,0 ± 16,3 g, HR 1,02 [1,00-1,04], p = 0,033). Finally VT recurrence was higher in patients with channels with transmural path (66,7% vs 31,4%, HR 3,25 [1,70-6,23], p < 0,001) or midmural channels (54,3% vs 27,6%, HR 2,49 [1,21–5,13], p = 0,013).

CMR-aided scar dechanneling is a helpful and feasible technique which could identify patients with high risk of VT recurrence. High left ventricular mass, septal LGE distribution, transmural and midmural heterogeneous tissue channels were predictive factors of post ablation VT recurrence.

Abstract Figure. VTchannel & heterogeoneus tissue channel

Tolerability and safety of dimethyl fumarate in relapsing multiple sclerosis: a prospective observational multicenter study in a real-life Spanish population

BACKGROUND

Dimethyl fumarate (DMF) tolerability and safety in multiple sclerosis (MS) has been analyzed in randomized clinical trials. Real-life studies are needed to assess possible harms of this therapy in a wider MS population.

OBJECTIVE

To evaluate DMF tolerability, safety and persistence in MS in a real-world setting.

METHODS

We conducted a multicenter prospective study of patients who started DMF, attended in 16 public hospitals of Spain. A specific database was elaborated to collect data on most frequent adverse events (AE). Regression models were used to analyze the effect of demographic and clinical characteristics on risk of AEs and DMF discontinuation.

RESULTS

We collected data of 886 patients (2681 patients/years-exposition) with median 39.5 (IQR 23, 51.5) months on DMF exposure; 25.3% were treatment naïve and 74.7% switched to DMF from other disease-modifying therapies. DMF was discontinued in 29.9% of patients, in 13.2% due to AEs and in 13.5% to inefficacy. AEs were experienced by 71.2%, being flushing the most frequent (44.1%), 5.4% developed grade III lymphopenia, without cases of grade IV. Females showed a higher risk of flushing and gastroenteric symptoms (OR 1.49, p = 0.011; OR 1.69, p = 0.001, respectively); lymphopenia was associated with older age (OR 1.04, p < 0.001), and a higher EDSS with lymphopenia (OR 1.10, p = 0.035) and DMF withdrawal (HR 1.43, p = 0.012). No safety problems were reported.

CONCLUSIONS

Our findings confirm good tolerability and safety of DMF in real-world setting and suggest that women have an increased risk of AEs and higher baseline disability involves greater risk of drug discontinuation.

MON-385 Malignant Pheochromocytoma/Paraganglioma Syndrome during Pregnancy: Clinical Case Report, a Therapeutic Challenge

Background: Arterial hypertension due to endocrine disease is 3% of secondary causes, being more frequent in the young. Excess of mineralocorticoids, catecholamines and glucocorticoids is potentially curable with the appropriate treatment. Pheochromocytoma/Paraganglioma syndrome is 0.2 to 0.6% of the cause. Clinical Case: 27 year old woman with previously known left pheochromocytoma, treated with laparoscopic adrenalectomy in 2010, with biochemical tests, ruling out new lesions and being able to stop antihypertensive treatment. In 2017, a twenty week old pregnancy was stopped due to elevated arterial pressure. The patient consults in December 2017 with a 15th week old pregnancy, complaining of catecholaminergic symptoms and a hypertensive crisis in the emergency range. Initial treatment was labetalol with partial control of symptoms. Normetanephrines in plasma were elevated (2298 pg/mL, NR: < 180pg/mL). During follow up additional antihypertensive management was required with prazosin, clonidine and nifedipine achieving adequate control of hypertension, without complete control of symptoms. A Non contrasted MRI of the abdomen was performed where a retroperitoneal ganglionar conglomerate of 96mm around the aorta was documented. Additional finding were a cervical adenopathy in a computed tomography (CT) and a lytic bone in T7 and right ribcage, pulmonary nodule of 12mm in the lingula without other lesions in lung. Bone scintigraphy confirmed bone lesions, which made the diagnosis of malignant pheochromocytoma paranglioma syndrome (PPS). Cytoreductive surgery followed the management, for biochemical, clinical control and overall increase in survival. During the surgery dissection of the abdominal mass from the aorta to the iliac artery bifurcation, left nephrectomy and splenectomy were required. Obstetric ultrasonography found fetal suffering which led to an obstetric curettage. Pathology reports intermediate cells in an organoid pattern compatible with neuroendocrine neoplasia. Inmunohistochemistry with positivity for chromogranin, synaptophysin, inhibin and S100. AE1/AE3 showed focal positivity in neoplasic cells. Calretinin and MELAN-A were negative. These results confirmed the diagnostic suspicion of paraganglioma. Knowing the autosomal dominant inheritance pattern and variable expression, in the context of malignant PPS genetic studies were performed for the succinate dehydrogenase B and D, von hippler lindau and fumarate hidratase. Clinical evolution was satisfactory with decrease in the number and dosage of antihypertensives, control of arterial hypertension and a reduction in catecholaminergic symptoms. Conclusion: This is the first case of malignant PPS during pregnancy. Clinical control of the disease was obtained, with decrease in antihypertensive and control of symptoms. Unfortunately with a fetal loss during the treatment of the patient

SAT-582 Autoimmune Hepatitis Presenting with Graves Disease

Graves disease, the most common cause of hyperthyroidism in the world has an incidence peak between 30 and 50 years of age. It is more frequent in women that in men with a ratio of 5:1. The typical presentation is thyrotoxicosis, goiter and opthalmopathy. The most specific laboratory finding is the activating autoantibodies directed against the thyrotropin receptor, present in up to 98% of untreated patients. Considering the autoimmune nature of the disease, it is not uncommon that patients with the disease present with other autoimmune identities. We present a 22 year old woman diagnosed with Graves disease two years previous, taking methimazole irregularly for 1.5 years. Iodine treatment was given with previous suspension of methimazole a week before. Three days before Iodine she presents jaundice and malaise and comes into the emergency room. Laboratory studies showed transaminases that reached a maximum level of AST 1601U/L (NV: 12-38U/L) ALT 1407U/L (NV: 7-41), total bilirubin of 34.4mg/dl (NV: 0.3-1.3mg/dl) with a conjugated bilirubin of 29.9mg/dl (NV: 0.1-0.4mg/dl) and alkaline phosphatase of 762U/L (NV: 33-96U/L), TSH 0.015 mUI/L T4L 90 pmol/L, abdominal ultrasound showed cholecystitis without cholelithiasis or enlargement of the bile duct and markers of viral hepatitis were negative. A liver biopsy was performed due to hepatocellular injury that reported chronic severe inflammatory infiltrate and acute portal with focal interfase lesion with plasmocytes. Mild fibrous expansion of portal spaces compatible with chronic active hepatitis of probable autoimmune etiology. The autoimmune labs reports showed IgG 2146mg/dl, Antinuclear antibodies negative, Anti smooth muscle antibodies negativa and anti mitochondrial antibodies that were positive. In this case the diagnosis of autoimmune hepatitis and primary biliary cirrhosis was made considering an overlap disease in the context of hyperthyroidism. Patients with Graves disease can have other autoimmune diseases such as autoimmune hepatitis which should be actively searched as a differential diagnosis. Other hepatic diseases such as viral hepatitis, drug induced hepatitis or deposit disease should be ruled out. Smith, T; Hegedüs, L. Review Article: Graves` Disease. N Engl J Med 2016;375:1552-65. Menconi, F; Marcocci, C; Marinò, M. Review: Diagnosis and Classification of Graves` disease. Autoimmun Rev (2014), http://dx.doi.org/10.1016/j.autrev.2014.01.013. Teufel, A; Weinmann, A; Kahaly, G; et all. Concurrent Autoimmune diseases in patients with Autoimmune hepatitis. J Clin Gastroenterol 2010;44:208-213. Wang, R; Tan, J; Zhang, G; et all. Risk factors of hepatic dysfunction in patients with Graves´ hyperthyroidism and the efficacy of 131iodine treatment. Medicine (2017) 96:5. Jhee, J; Kim, H; Kang, W; et all. A case of autoimmune hepatitis combined with graves disease. Korean J Gastroenterol; 2015; 65, 48-51.

SAT-580 Tocilizumab Improvement in a Patient with Corticosteroid Resistant Thyroid Orbitopathy: Report of a Case

Thyroid orbithopathy is an autoimmune disorder being the most frequent extrathyroideal manifestation. It can present before or even years after hyperthyroidism, although occasionally in nonhyperthyroid patients. The severe form has been described in 5% of the presentations. Treatment begins with smoking cessation, and maintenance of euthyroidism. The active forms are treated with systemic glucocorticoids however there is a 20% of nonresponder. Tocilizumab has been effectively used in corticosteroid resistant ophthalmopathy. There are reports of other treatments used such as rituximab with conflicting results which is why we decided to use tocilizumab. 1,2. We present two cases: a 59 year old woman with ophthalmopathy and hyperthyroidism treated since 2017 with tocilizumab. At the moment of receiving the medication they were euthyroid with severe orbitopathy measured by a clinical activity score of 6 refractory to systemic steroid treatment with previous use of six grams without disease control. We considered biological therapy after surgical decompression with tocilizumab at a dose of 8 mg per kilogram every four weeks during four months. The patient changed from a CAS of 6 to a CAS of 1 having an associated improvement in quality of life. A second woman of 55 years was started after receiving 6 grams of methylprednisolone without any improvement of the CAS. She started with a CAS of 6 and is currently at 3 with the third dose of tocilizumab.Tocilizumab is a humanized monoclonal immunoglobulin G1 antibody to the interleukin 6 receptor that has been used in rheumatoid arthritis. The pathophysiology starts with autoreactive B cells that recognize de TSH receptor as an autoantigen and secrete interleukin 6 amongst others that stimulate fibroblasts with the rest of the cascade. A reduction of proptosis with a mean of 3.92mm, 83% showed improvement in visual motility, 53.8% had resolution of diplopia, improvement of CAS up to 27 months without severe adverse effects reported. Some type of improvement has been reported in some series in 100% of patients. 2 Bibliography Stan, M; Garity, J; Carranza, B; et all. Randomized Controlled Trial of Rituximab in Patients With Graves Orbitopathy. J Clin Endocrinol Metab 100(2015): 432-411. Perez, J; Alvarez, A; Gomez E. Treatment of active corticosteroid resistant graves orbitophaty. Ophthalmic Plast Reconstr Surg 2014;30:162-167. Wiersinga, W. Advances in treatment of active, moderate to severe graves ophthlamopathy. Lanced Diabetes and Endocrinol 2016:1-9. Russel, D; Wagner, L; Seiff, S. Toxiclizumab as a steroid sparing agent for the treatment of Graves orbitopathy. American Journal of Ophthlamology Case Reports 7(2017)146-148.

Micro and Nanostructured Materials for the Development of Optical Fibre Sensors

The measurement of chemical and biomedical parameters can take advantage of the features exclusively offered by optical fibre: passive nature, electromagnetic immunity and chemical stability are some of the most relevant ones. The small dimensions of the fibre generally require that the sensing material be loaded into a supporting matrix whose morphology is adjusted at a nanometric scale. Thanks to the advances in nanotechnology new deposition methods have been developed: they allow reagents from different chemical nature to be embedded into films with a thickness always below a few microns that also show a relevant aspect ratio to ensure a high transduction interface. This review reveals some of the main techniques that are currently been employed to develop this kind of sensors, describing in detail both the resulting supporting matrices as well as the sensing materials used. The main objective is to offer a general view of the state of the art to expose the main challenges and chances that this technology is facing currently.

Does Hypoxic Response Mediate Primary Resistance to Sunitinib in Untreated Locally Advanced Breast Cancer?

BACKGROUND

The antiangiogenic drug sunitinib has never been evaluated as single agent in untreated breast cancer patients.

OBJECTIVE

We aimed to characterize the activity of sunitinib, alone and with docetaxel, in untreated locally advanced or operable breast cancer and to uncover the mechanisms of response.

METHOD

Patients were treated with an upfront window of sunitinib followed by four cycles of sunitinib plus docetaxel. Response, resistance and toxicity were evaluated according to standard clinical parameters, magnetic resonance imaging, positron emission tomography, standard pathology characterization, molecular pathology and gene expression profiling.

RESULTS

Twelve patients were included. We detected primary resistance to sunitinib in the upfront window in untreated breast cancer, as evidenced by four non-responding patients. At surgery, five patients had viable tumor in the breast and axilla, four had viable tumor cells in the breast alone and three were taken off study and thus not evaluated, due to unacceptable toxicity. Early functional imaging was useful in predicting response. There were no clinical complete responses. Comparison of tumor gene expression profiling data between early responders and non-responders allowed us to identify the up-regulation of VEGF and angiogenic pathways in non-responders. Specifically, in tumors resistant to single-agent sunitinib we detected a transcriptional response to hypoxia characterized by over-expression of several HIF1α target genes.

CONCLUSION

In this report of single-agent sunitinib treatment in untreated localized breast cancer patients, we found evidence of primary resistance to sunitinib, likely mediated by up-regulation of hypoxia responsive genes.

Malformaciones congénitas del oído externo y medio en pacientes de la Cátedra de Otorrinolaringología, Facultad de Ciencias Médicas, Universidad Nacional de Asunción, Paraguay

Introducción: Los recién nacidos tienen una alta incidencia de deformidades del oído, causadas por las interacciones de una serie de factores. La ubicación, los síntomas clínicos, los hallazgos de imágenes y un alto índice de sospecha ayudan al diagnóstico de las malformaciones del oído. Las estructuras del oído medio y del externo proceden del primer y del segundo arcos branquiales. Como las mismas se encuentran relacionadas ya desde su origen, así también lo pueden estar sus alteraciones. Objetivo: El presente trabajo se realizó para conocer la frecuencia de las malformaciones congénitas del oído en nuestro medio y, además, con el objetivo de que sea una base para futuras investigaciones sobre el tema. Metodología: Estudio observacional descriptivo transverso, con muestreo no probabilístico de casos consecutivos, llevado a cabo en la Cátedra y Servicio de Otorrinolaringología de la Facultad de Ciencias Médicas, Universidad Nacional de Asunción, en junio de 2017. Se analizaron 5781 historias clínicas de pacientes que consultaron a la Unidad de Otología, entre enero 2006 a mayo 2017. Las variables exploradas fueron: edad (en años cumplidos), sexo (masculino, femenino), motivo de consulta y diagnóstico. Los datos fueron analizados utilizando estadística descriptiva.  Resultados: Se encontró una frecuencia de 1,07% de malformaciones congénitas del oído externo y medio, lo que representa un total de 63 pacientes. De los 63 pacientes con malformaciones congénitas, el 52% era del sexo femenino (33 pacientes), con edades comprendidas entre 1 y 70 años (media: 26,42). El diagnóstico más prevalente fue el de fistula auris (33%). Los motivos de consultas más frecuentes fueron la tumoración cervical (32%) y la hipoacusia (25%). Discusión: Resulta importante tanto para el pediatra como para el otorrinolaringólogo lograr identificar precozmente las malformaciones congénitas del oído, para así poder instaurar terapéuticas oportunas y acertadas, que mejoren ampliamente la calidad de vida de los pacientes. Palabras clave: Malformaciones congénitas; Oído externo; Oído medio

Poorly Differentiated Medullary Phenotype Predicts Poor Survival in Early Lymph Node-Negative Gastro-Esophageal Adenocarcinomas

BACKGROUND

5-year survival rate in patients with early adenocarcinoma of the gastro-esophageal junction or stomach (AGE/S) in Caucasian patients is reported to be 60-80%. We aimed to identify prognostic markers for patients with UICC-I without lymph-node involvement (N0).

METHODS

Clinical data and tissue specimen from patients with AGE/S stage UICC-I-N0, treated by surgery only, were collected retrospectively. Tumor size, lymphatic vessel or vein invasion, grading, classification systems (WHO, Lauren, Ming), expression of BAX, BCL-2, CDX2, Cyclin E, E-cadherin, Ki-67, TP53, TP21, SHH, Survivin, HIF1A, TROP2 and mismatch repair deficiency were analyzed using tissue microarrays and correlated with overall and tumor related survival.

RESULTS

129 patients (48 female) with a mean follow-up of 129.1 months were identified. 5-year overall survival was 83.9%, 5-year tumor related survival was 95.1%. Poorly differentiated medullary cancer subtypes (p<0.001) and positive vein invasion (p<0.001) were identified as risk factors for decreased overall-and tumor related survival. Ki-67 (p = 0.012) and TP53 mutation (p = 0.044) were the only immunohistochemical markers associated with worse overall survival but did not reach significance for decreased tumor related survival.

CONCLUSION

In the presented study patients with AGE/S in stage UICC-I-N0 had a better prognosis as previously reported for Caucasian patients. Poorly differentiated medullary subtype was associated with reduced survival and should be considered when studying prognosis in these patients.