eXiTCDSS: A framework for a workflow-based CBR for interventional Clinical Decision Support Systems and its application to TAVI

This work has been financed by the Spanish Government Commission Ministerio de Industria, Turismo y Comercio (MITyC) under the project PLAN AVANZA 2 labeled by Information Technology for European Advancement 2 (ITEA2). Also, this research project has been partially funded through the project labeled DPI2011-24929.International audienceClinical Decision Support System (CDSSs) should form an important part of the field of clinical knowledge management technologies through their capacity to support the clinical process and use of knowledge, including knowledge maintenance and continuous learning, from diagnosis and investigation through surgery, treatment and long-term care. The work presented shows a workflow-based CDSS designed to give case-specific assessment to clinicians during complex surgery or Minimally Invasive Surgery (MISs). Following a perioperative workflow, the designed software will use a Case-Based Reasoning (CBR) methodology to retrieve similar past cases from a case base to provide support at any particular point of the process. The graphical user interface allows easy navigation through the whole support progress, from the initial configuration steps to the final results organized as sets of experiments easily visualized in a user-friendly way. The eXiTCDSS tool is presented giving support to a recent complex minimally invasive surgery which is receiving growing attention lately, the Transcatheter Aortic Valve Implantation (TAVI). The results obtained are presented on a basis of a real TAVI case base of 82 patients operated at Rennes University Hospital

0081: Prevalence and determinants or right ventricular dysfunction in severe aortic stenosis

Introductionsystolic pulmonary artery pressure (sPAP) is a well known predictor of outcome in patients with valvular heart disease. In spite of this fact, limited data are available regarding the assessment of RV function in patients with aortic stenosis (AS).Aimof this study is therefore to evaluate the prevalence and the determinants of RV dysfunction in severe AS patientsMethods201 patients (mean age:79.7±8.7, male sex 55.5%) with severe AS underwent 2D echocardiography and speckle tracking echocardiography (STE) for the evaluation of left ventricular and RV function, aortic valve gradients and sPAP. A tricuspid annular plane systolic excursion (TAPSE) ≤17mm was used to define reduced RV ventricular function.ResultsRV function was impaired in 48 patients (24%). Patients with reduced TAPSE had an impaired LV ejection fraction (LVEF) (49.2±15.4 vs 57.9±10.9%, p<0.0001), significantly altered STE parameters (GLS: –10.3 ±3.9 vs –13.2±3.5%, GCS: –7.0±3. vs –10.4±4.9%, GRS: 18.7±11.6 vs 28.4±15.6, all p<0.001) and a higher sPAP (48.4±15.8 vs 40.9±12.7mmHg, p=0.002) with respecto to patients with a normal RV function. Correlates of a reduced TAPSE were: LVEF (β=0.35, p<0.0001), LV global longitudinal, circumferential and radial strain (β=–0.40, β=–0.40, β=0.37 respectively, all p<0.0001), LV indexed stroke volume (β=0.44, s<0.0001), lnNT-proBNP (β=–0.51, p<0.0001) and sPAP (β=–0.27, p<0.0001). At Kaplan-Meier survival curve, a TAPSE ≤17mm was associated with a reduced survival in patients with AS (Log Rank test, p=0.034).ConclusionsIn patients with severe AS, RV function impairment is frequent and is associated with a poor prognosis. The correlations of TAPSE highlight the RV-LV interdependence in AS patients. Further studies will clarify the real and independent prognostic value of RV function in severe AS patients and test for the RV reverse remodelling after treatment of the AS

Review of patient-specific simulations of transcatheter aortic valve implantation

International audienceTranscatheter Aortic Valve Implantation (TAVI) accounts for one of the most promising new cardiovascular procedures. This minimally invasive technique is still at its early stage and is constantly developing thanks to imaging techniques, computer science, biomechanics and technologies of prosthesis and delivery tools. As a result, patient-specific simulation can find an exciting playground in TAVI. It canexpress its potential by providing the clinicians with powerful decision support, offering great assistance in their workflow. Through a review of the current scientific field, we try to identify the challenges and future evolutions of patient-specific simulation for TAVI. This review article is an attempt to summarize and coordinate data scattered across the literature about patient-specific biomechanical simulation for TAVI

Reversible, electric-field induced magneto-tonic control of magnetism in mesoporous cobalt ferrite thin films

The magnetic properties of mesoporous cobalt ferrite films can be largely tuned by the application of an electric field using a liquid dielectric electrolyte. By applying a negative voltage, the cobalt ferrite becomes reduced, leading to an increase in saturation magnetization of 15% (M) and reduction in coercivity (H) between 5-28%, depending on the voltage applied (−10 V to −50 V). These changes are mainly non-volatile so after removal of −10 V M remains 12% higher (and H 5% smaller) than the pristine sample. All changes can then be reversed with a positive voltage to recover the initial properties even after the application of −50 V. Similar studies were done on analogous films without induced porosity and the effects were much smaller, underscoring the importance of nanoporosity in our system. The different mechanisms possibly responsible for the observed effects are discussed and we conclude that our observations are compatible with voltage-driven oxygen migration (i.e., the magneto-ionic effect)

Prolactin induces apoptosis of lactotropes in female rodents

Anterior pituitary cell turnover occurring during female sexual cycle is a poorly understood process that involves complex regulation of cell proliferation and apoptosis by multiple hormones. In rats, the prolactin (PRL) surge that occurs at proestrus coincides with the highest apoptotic rate. Since anterior pituitary cells express the prolactin receptor (PRLR), we aimed to address the actual role of PRL in the regulation of pituitary cell turnover in cycling females. We showed that acute hyperprolactinemia induced in ovariectomized rats using PRL injection or dopamine antagonist treatment rapidly increased apoptosis and decreased proliferation specifically of PRL producing cells (lactotropes), suggesting a direct regulation of these cell responses by PRL. To demonstrate that apoptosis naturally occurring at proestrus was regulated by transient elevation of endogenous PRL levels, we used PRLR-deficient female mice (PRLRKO) in which PRL signaling is totally abolished. According to our hypothesis, no increase in lactotrope apoptotic rate was observed at proestrus, which likely contributes to pituitary tumorigenesis observed in these animals. To decipher the molecular mechanisms underlying PRL effects, we explored the isoform-specific pattern of PRLR expression in cycling wild type females. This analysis revealed dramatic changes of long versus short PRLR ratio during the estrous cycle, which is particularly relevant since these isoforms exhibit distinct signaling properties. This pattern was markedly altered in a model of chronic PRLR signaling blockade involving transgenic mice expressing a pure PRLR antagonist (TGΔ1–9-G129R-hPRL), providing evidence that PRL regulates the expression of its own receptor in an isoform-specific manner. Taken together, these results demonstrate that i) the PRL surge occurring during proestrus is a major proapoptotic signal for lactotropes, and ii) partial or total deficiencies in PRLR signaling in the anterior pituitary may result in pituitary hyperplasia and eventual prolactinoma development, as observed in TGΔ1–9-G129R-hPRL and PRLRKO mice, respectively.Fil: Ferraris, Maria Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; Argentina; Argentina. Universidad de Buenos Aires; ArgentinaFil: Zarate, Sandra Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; Argentina; Argentina. Universidad de Buenos Aires; ArgentinaFil: Jaita, Gabriela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; Argentina; Argentina. Universidad de Buenos Aires; ArgentinaFil: Boutillon, Florencia. Universite Paris Sud; FranciaFil: Bernadet, Marie. Universite Paris Descartes; FranciaFil: Auffret, Julien. Universite Paris Sud; FranciaFil: Seilicovich, Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; Argentina; Argentina. Universidad de Buenos Aires; ArgentinaFil: Binart, Nadine. Universite Paris Sud; FranciaFil: Goffin, Vincent. Universite Paris Descartes; FranciaFil: Pisera, Daniel Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; Argentina; Argentina. Universidad de Buenos Aires; Argentin

Forest cover mask from historical topographic maps based on image processing

This study aimed to obtain accurate binary forest masks which might be directly used in analysis of land cover changes over large areas. A sequence of image processing operations was conceived, parameterized and tested using various topographic maps from mountain areas in Poland and Switzerland. First, the input maps were filtered and binarized by thresholding in Hue-Saturation-Value colour space. The second step consisted of a set of morphological image analysis procedures leading to final forest masks. The forest masks were then assessed and compared to manual forest boundary vectorization. The Polish topographical map published in the 1930s showed low accuracy which could be attributed to methods of cartographic presentation used and degradation of original colour prints. For maps published in the 1970s, the automated forest extraction performed very well, with accuracy exceeding 97%, comparable to accuracies of manual vectorization of the same maps performed by nontrained operators. With this method, we obtained a forest cover mask for the entire area of the Polish Carpathians, easily readable in any Geographic Information System software

: Gender differences in STEMI

International audienceBACKGROUND: Gender differences in presentation, management and outcome in patients with ST-segment elevation myocardial infarction (STEMI) have been reported. AIM: To determine whether female gender is associated with higher inhospital mortality. METHODS: Data from ORBI, a regional STEMI registry of 5 years' standing, were analysed. The main data on presentation, management, inhospital outcome and prescription at discharge were compared between genders. Various adjusted hazard ratios were then calculated for inhospital mortality (women versus men). RESULTS: The analysis included 5000 patients (mean age 62.6±13 years), with 1174 women (23.5%). Women were on average 8 years older than men, with more frequent co-morbidities. Median ischaemia time was 215 minutes (26 minutes longer in women; P<0.05). Reperfusion strategies in women less frequently involved fibrinolysis, coronary angiography, radial access and thrombo-aspiration. Female gender, especially in patients aged<60 years, was associated with poorer inhospital prognosis (including higher inhospital mortality: 9% vs. 4% in men; P<0.0001), and underutilization of recommended treatments at discharge. Moreover, excess female inhospital mortality was independent of presentation, revascularization time and reperfusion strategy (hazard ratio for women 1.33, 95% confidence interval 1.01-1.76; P=0.04). CONCLUSIONS: One in four patients admitted for STEMI was female, with significant differences in presentation. Female gender was associated with less-optimal treatment, both in the acute-phase and at discharge. Efforts should be made to reduce these differences, especially as female gender was independently associated with an elevated risk of inhospital mortality

Decision support for transcatheter aortic valve implantation

La sténose aortique serrée est la valvulopathie acquise de l’adulte la plus fréquente affectant jusqu’à 10% des octogénaires. Sa prise en charge percutanée est en plein essor et confronte les cliniciens à des problèmes nouveaux constituant un champ de recherche important. Notre travail s’inscrit dans le cadre des gestes médico-chirurgicaux assistés par ordinateur et vise à proposer des solutions d’aide à la décision basées sur l’assistance informatique. Cette Thèse est ainsi composée de 4 parties. Une première partie porte sur la problématique médicale dans laquelle s’inscrit le remplacement valvulaire aortique percutané (TAVI) ainsi que le contexte du TAVI en France et présente un article évaluant l’évolution des caractéristiques des patients et des procédures à l’échelle nationale entre 2010 et 2015 dans les registres nationaux FRANCE 2 et FRANCE TAVI. Ce premier chapitre identifie des problématiques médicales auxquelles les opérateurs sont confrontés au quotidien notamment la sélection optimale des candidats et la minimisation des complications de la procédure dans le contexte d’une réduction du profil de risque des patients traités. La seconde partie s’intéresse à l’étude de populations, par des méthodes statistiques classiques, pour établir des facteurs prédictifs de résultats du TAVI ou de survenue d’une complication donnée afin d’aider le clinicien dans sa planification de la procédure. Cette partie est articulée autour de 3 articles portant sur les facteurs prédictifs d’accidents vasculaires cérébraux, les troubles conductifs et les facteurs prédictifs de « mauvais résultats » après TAVI. Nous démontrons l’intérêt de ce type d’analyse qui resteront nécessaires à l’avenir mais abordons également leurs limites qui expliquent pourquoi d’autres pistes doivent être explorées pour stocker, trier, restituer les informations pertinentes à l’opérateur voire les augmenter pour faciliter ses décisions notamment en préopératoire.L’objet de la 3ème partie est d’aborder un système d’aide à la décision par ordinateur de type « case-based reasoning » (CBR) qui pourrait tirer bénéfice de l’identification de ces facteurs pronostiques et à terme les intégrer dans une interface globale et ergonomique d’aide à la décision. Nous avons travaillé dans le cadre du projet européen H2020 EurValve sur l’élaboration d’un CBR dont la problématique se concentre pour l’instant sur le choix optimal de la voie d’abord, du type et de la taille de prothèse. Notre travail s’est concentré sur une étape analytique de la conception de ce type de système portant sur l’étude et l’amélioration de la mesure de similarité utilisée pour rapprocher le cas à traiter (problème) de ses plus proches voisins (cas déjà traités et leur « solution » thérapeutique). Enfin, une dernière partie porte sur l’augmentation des informations disponibles pour l’aide à la décision en préopératoire par la simulation numérique spécifique patient. Après un état de l’art des méthodes utilisées dans le domaine du TAVI, nous avons travaillé à l’élaboration et au paramétrage d’un modèle de simulation de l’insertion du guide rigide dans le ventricule gauche (une étape de la procédure qui peut conditionner le positionnement de la prothèse et donc le résultat final). Afin de réaliser une première validation de cette simulation exploitant l’imagerie tomodensitométrique 3D préopératoire, l’approche proposée repose sur l’extraction de la région d’intérêt dans le volume 3D (segmentation) et sa mise en correspondance avec l’imagerie fluoroscopique 2D peropératoire par le biais d’un recalage 3D/2D. Nos travaux sur ces méthodes de traitement de l’image nécessaires à la mise en œuvre et la validation de notre stratégie de simulation sont discutés dans cette partie. Enfin nous présentons une application clinique potentielle du modèle de simulation portant sur l’influence de la forme du guide et de ses conditions d’insertion sur sa stabilité et les forces de pression s’exerçant sur le ventricule gaucheAortic stenosis represents the most frequent acquired valvular heart disease, affecting up to 10% of octogenarians. Transcatheter aortic valve implantation (TAVI) is booming and confronts clinicians with new issues that constitute a major field of research. Our work falls within the framework of computer-assisted medico-surgical interventions, and aims at proposing computer-assisted decision support systems. The present Thesis is composed of four parts. The first part focuses on the medical problematic surrounding TAVI, as well as the current French TAVI field on the basis of an article describing temporal trends in patients’ and procedural’s characteristics from 2010 to 2015 in the FRANCE 2 and FRANCE TAVI nationwide registries. This first part identifies medical issues that operators currently face, especially the optimal selection of TAVI candidates, and the reduction of procedural complications within the current trends towards treatment of patients with lower baseline surgical-risk profile. The second part deal with population-based studies, through standard statistical methods, to identify predictors of TAVI outcomes or selected procedural complications in order to facilitate procedural planning. Three articles compose this part. The first focuses on predictors of short-term cerebrovascular events post-TAVI, the second deals with conduction disturbances post-TAVI while the third aims at identifying predictors of global poor outcomes. We demonstrate the benefits of these analyses, which will remain necessary in the future, but also address their limitations, which support the use of new methods to store, sort, retrieve, and even augment relevant information to facilitate operators’ decision, especially at the pre-procedural step.The purpose of Part 3 is to address a case-based reasoning (CBR) decision-support system that could benefit from the identification of these prognostic factors and ultimately integrate them into a global and ergonomic interface for decision support. We have worked in the framework of the European project H2020 EurValve on the development of a CBR whose problematic is,for the time being, limited to the optimal choice of the approach, type and size of prosthesis. Our work focused on an analytical step in the design of this type of system dealing with the study and improvement of the similarity measure used to identify nearest neighbours (previously treated cases and their therapeutic "solution") of the current problem (case which clinicians are planning to treat). Finally, the last part focuses on increasing the information available for preoperative decision support through patient-specific numerical simulation. After a state of the art of the methods used in the field of TAVI, we worked on the elaboration and parameterization of a simulation model of the insertion of the stiff guidewire in the left ventricle (one of the first steps of the procedure that can condition the positioning of the prosthesis and thus the final result). In order to perform a first validation of this patient-specific simulation using preoperative 3D CT imaging, the proposed approach is based on the extraction of the region of interest in the 3D volume (segmentation) and its mapping to intraoperative 2D fluoroscopy through 3D / 2D registration. Our work on these image processing methods needed to implement and validate our simulation strategy is also discussed in this section. Finally, we present a potential clinical application of the simulation model regarding the influence of the shape of the guide and its insertion conditions on its stability and the pressure forces exerted on the left ventricle

Aide à la décision pour le remplacement valvulaire aortique percutané

Aortic stenosis represents the most frequent acquired valvular heart disease, affecting up to 10% of octogenarians. Transcatheter aortic valve implantation (TAVI) is booming and confronts clinicians with new issues that constitute a major field of research. Our work falls within the framework of computer-assisted medico-surgical interventions, and aims at proposing computer-assisted decision support systems. The present Thesis is composed of four parts. The first part focuses on the medical problematic surrounding TAVI, as well as the current French TAVI field on the basis of an article describing temporal trends in patients’ and procedural’s characteristics from 2010 to 2015 in the FRANCE 2 and FRANCE TAVI nationwide registries. This first part identifies medical issues that operators currently face, especially the optimal selection of TAVI candidates, and the reduction of procedural complications within the current trends towards treatment of patients with lower baseline surgical-risk profile. The second part deal with population-based studies, through standard statistical methods, to identify predictors of TAVI outcomes or selected procedural complications in order to facilitate procedural planning. Three articles compose this part. The first focuses on predictors of short-term cerebrovascular events post-TAVI, the second deals with conduction disturbances post-TAVI while the third aims at identifying predictors of global poor outcomes. We demonstrate the benefits of these analyses, which will remain necessary in the future, but also address their limitations, which support the use of new methods to store, sort, retrieve, and even augment relevant information to facilitate operators’ decision, especially at the pre-procedural step.The purpose of Part 3 is to address a case-based reasoning (CBR) decision-support system that could benefit from the identification of these prognostic factors and ultimately integrate them into a global and ergonomic interface for decision support. We have worked in the framework of the European project H2020 EurValve on the development of a CBR whose problematic is,for the time being, limited to the optimal choice of the approach, type and size of prosthesis. Our work focused on an analytical step in the design of this type of system dealing with the study and improvement of the similarity measure used to identify nearest neighbours (previously treated cases and their therapeutic "solution") of the current problem (case which clinicians are planning to treat). Finally, the last part focuses on increasing the information available for preoperative decision support through patient-specific numerical simulation. After a state of the art of the methods used in the field of TAVI, we worked on the elaboration and parameterization of a simulation model of the insertion of the stiff guidewire in the left ventricle (one of the first steps of the procedure that can condition the positioning of the prosthesis and thus the final result). In order to perform a first validation of this patient-specific simulation using preoperative 3D CT imaging, the proposed approach is based on the extraction of the region of interest in the 3D volume (segmentation) and its mapping to intraoperative 2D fluoroscopy through 3D / 2D registration. Our work on these image processing methods needed to implement and validate our simulation strategy is also discussed in this section. Finally, we present a potential clinical application of the simulation model regarding the influence of the shape of the guide and its insertion conditions on its stability and the pressure forces exerted on the left ventricle.La sténose aortique serrée est la valvulopathie acquise de l’adulte la plus fréquente affectant jusqu’à 10% des octogénaires. Sa prise en charge percutanée est en plein essor et confronte les cliniciens à des problèmes nouveaux constituant un champ de recherche important. Notre travail s’inscrit dans le cadre des gestes médico-chirurgicaux assistés par ordinateur et vise à proposer des solutions d’aide à la décision basées sur l’assistance informatique. Cette Thèse est ainsi composée de 4 parties. Une première partie porte sur la problématique médicale dans laquelle s’inscrit le remplacement valvulaire aortique percutané (TAVI) ainsi que le contexte du TAVI en France et présente un article évaluant l’évolution des caractéristiques des patients et des procédures à l’échelle nationale entre 2010 et 2015 dans les registres nationaux FRANCE 2 et FRANCE TAVI. Ce premier chapitre identifie des problématiques médicales auxquelles les opérateurs sont confrontés au quotidien notamment la sélection optimale des candidats et la minimisation des complications de la procédure dans le contexte d’une réduction du profil de risque des patients traités. La seconde partie s’intéresse à l’étude de populations, par des méthodes statistiques classiques, pour établir des facteurs prédictifs de résultats du TAVI ou de survenue d’une complication donnée afin d’aider le clinicien dans sa planification de la procédure. Cette partie est articulée autour de 3 articles portant sur les facteurs prédictifs d’accidents vasculaires cérébraux, les troubles conductifs et les facteurs prédictifs de « mauvais résultats » après TAVI. Nous démontrons l’intérêt de ce type d’analyse qui resteront nécessaires à l’avenir mais abordons également leurs limites qui expliquent pourquoi d’autres pistes doivent être explorées pour stocker, trier, restituer les informations pertinentes à l’opérateur voire les augmenter pour faciliter ses décisions notamment en préopératoire.L’objet de la 3ème partie est d’aborder un système d’aide à la décision par ordinateur de type « case-based reasoning » (CBR) qui pourrait tirer bénéfice de l’identification de ces facteurs pronostiques et à terme les intégrer dans une interface globale et ergonomique d’aide à la décision. Nous avons travaillé dans le cadre du projet européen H2020 EurValve sur l’élaboration d’un CBR dont la problématique se concentre pour l’instant sur le choix optimal de la voie d’abord, du type et de la taille de prothèse. Notre travail s’est concentré sur une étape analytique de la conception de ce type de système portant sur l’étude et l’amélioration de la mesure de similarité utilisée pour rapprocher le cas à traiter (problème) de ses plus proches voisins (cas déjà traités et leur « solution » thérapeutique). Enfin, une dernière partie porte sur l’augmentation des informations disponibles pour l’aide à la décision en préopératoire par la simulation numérique spécifique patient. Après un état de l’art des méthodes utilisées dans le domaine du TAVI, nous avons travaillé à l’élaboration et au paramétrage d’un modèle de simulation de l’insertion du guide rigide dans le ventricule gauche (une étape de la procédure qui peut conditionner le positionnement de la prothèse et donc le résultat final). Afin de réaliser une première validation de cette simulation exploitant l’imagerie tomodensitométrique 3D préopératoire, l’approche proposée repose sur l’extraction de la région d’intérêt dans le volume 3D (segmentation) et sa mise en correspondance avec l’imagerie fluoroscopique 2D peropératoire par le biais d’un recalage 3D/2D. Nos travaux sur ces méthodes de traitement de l’image nécessaires à la mise en œuvre et la validation de notre stratégie de simulation sont discutés dans cette partie. Enfin nous présentons une application clinique potentielle du modèle de simulation portant sur l’influence de la forme du guide et de ses conditions d’insertion sur sa stabilité et les forces de pression s’exerçant sur le ventricule gauch

Right Ventricular–Pulmonary Artery Coupling After Transcatheter Aortic Valve Replacement: Closer to Optimal Prognosis Assessment?

International audience[No abstract available