A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / compression of the right atrium and ventricle yet their LV function is within normal range. In the setting of normal LV function, symptomatic PE could potentially be the result of right heart compression causing right heart strain. Emphasis should therefore be placed on analyzing the presence and degree of right heart strain in patients with symptomatic pectus excavatum. When assessing for a correlation between the HI, CI, DI, or CCI together and independently with cardiopulmonary impairment, no significant relationships were identified. While it would be highly advantageous for a PE severity index to correlate with objective physiologic impairment, our data suggest that the currently defined indices fail to do so. Data confirming such a correlation would provide a means to measure both the severity of deformity and changes in functional disability in patients with PE. We aim to analyze the correlation between the HI and three new indices with cardiopulmonary impairment using the cardiopulmonary exercise test (CPET). In this study we evaluated the correlation of the Haller, correction, depression, and cardiac compression indices with functional cardiopulmonary impairment using preoperative cardiopulmonary exercise test (CPET) data. We hypothesize that the correction and cardiac compression indices will be strongly correlated with physiologic impairment in patients with PE, thus providing a novel means to measure functional disability as a function of disease severity. Study Design This is a retrospective study of 71 children between the ages of birth and 18 years of age who underwent evaluation for corrective surgery for pectus excavatum between 2010 and 2016 at Phoenix Children’s Hospital. Our final sample underwent preoperative computed tomography (CT) or MRI scan results as well as cardiopulmonary exercise testing. For each patient, the HI, CI, DI, and CCI were independently assessed using the PACS System by a single rater. Preoperative functional capacity was determined by measurement of peak oxygen consumption (VO2max reported as percent predicted) and stroke volume (a surrogate for cardiac output) which was assessed via the O2 pulse (VO2max/heart rate) reported as percent predicted. The possible values range from zero to 100% of the predicted value. Assessments Halller Index Correction Index Depression Index Cardiac Compression Index Correction, Depression, Cardiac Compression and Haller Indices Fail to Correlate with Cardiopulmonary Impairment in Pectus Excavatum Abstract Results Background: Pectus excavatum (PE) affects 1 in every 300 to 1,000 live births with a male to female ratio of 5:1, making it the most common congenital chest wall deformity in children. The standard for determining disease severity has become the Haller Index, which has been shown to poorly correlate with physiologic impairment. Recently, more novel indices have been introduced in an effort to more effectively represent disease burden. We aim to analyze the correlation between these indices and cardiopulmonary impairment in patients with PE using chest CT/ MRI as well as preoperative cardiopulmonary exercise testing data. Conclusions: We found that when assessing for a correlation between the HI, CI, DI, or CCI together and independently with cardiopulmonary impairment, both the linear and multiple regression models failed to identify a statistically significant relationship. While it would be highly advantageous for a PE severity index to correlate with objective physiologic impairment, our data suggest that the currently defined indices fail to do so.

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L’assistance ventriculaire constitue une voie thérapeutique prometteuse de l’insuffisance cardiaque terminale. En dépit des progrès, notamment dans le développement des assistances de type shunt ventriculo-aortique, les écueils relatifs à l’encombrement, à l’alimentation et/ou aux interactions avec le sang de ces dispositifs limitent leur application clinique. Récemment, le concept de Compression Cardiaque Directe (DCC) apparaît comme une piste prometteuse en palliant les difficultés sus-citées. Dans ce travail de thèse, nous avons mis l’accent sur la conception et le test de faisabilité d’une solution de Compression Cardiaque Directe de type mécanique et entièrement implantable appelée l’Exosquelette Cardiaque. Notre travail expérimental a porté, dans un premier temps, sur la conception assistée par ordinateur et sur la modélisation numérique permettant ainsi d’optimiser et de prédire (i) les interactions tissus myocardiques/dispositifs et (ii) les pressions ventriculaires générées. Ensuite, un prototype fonctionnel a été réalisé par fabrication additive (titane, polymères) en s’appuyant sur les données issues de la modélisation et en respectant les contraintes énergétiques, mécaniques et architecturales anatomiques. Enfin, nous avons conduit une phase d’évaluation du potentiel de ce dispositif original sur un modèle de cœur ex vivo. Nous avons pu concevoir et valider un modèle numérique fondé sur le principe des éléments finis. Ce modèle à la fois simple et robuste, a permis de simuler (i) l’impact des points de fixation du dispositif sur le tissu cardiaque, (ii) l’efficacité de la compression externe sur la genèse des pressions intraventriculaires et (iii) l’influence de la compression mécanique externe sur le tissu cardiaque. Le prototype issu de ce travail de thèse a pu produire des résultats prometteurs concernant (i) la restauration physiologique de la pression intraventriculaire, (ii) la consommation énergétique suffisamment basse et (iii) le design compatible avec les contraintes anatomiques thoracique. L’ensemble de ces résultats esquissent la possibilité d’une implantation totale de l’Exosquelette Cardiaque chez le patient / Ventricular assistance is a promising therapeutic pathway for terminal chronic heart failure. Notwithstanding the progress made for the development of aorto-ventricular shunt pump among other things, the difficulties relatives to footprint, power supply and/or blood-device interactions are somehow limiting their clinical applications. Recently, direct cardiac compression (DCC) was suggested as a promising lead to overcome the difficulties mentioned above. In this work, we focused on the design and the feasibility of an implantable and mechanical Direct Cardiac Compression device called: The Cardiac Exosqueleton. Our experimental work used Computer Assisted Design (CAD) and numerical modeling to optimize and predict (i) tissue-device interactions and (ii) pressure generation inside ventricular cavities. Then, a functional prototype was realized by additive manufacturing (titanium, polymer) with the help of modeling data and with respect to the anatomical, mechanical and energetical limitations. Finally, we conducted an evaluation of the ability of our device on both in vitro setup and ex vivo heart. We were able to conceive and validate a numerical model based on finite element techniques. This simple yet robust model allowed us to study (i) the impact of suture fixation of a device at the apex of the heart, (ii) the influence of the direct cardiac compression on intracardiac pressures and (iii) overall and local tissue stress in the myocardium. Our prototype showed promising results concerning (i) the restoration of physiological intraventricular pressures, (ii) a low energy consumption and (iii) a shape that is compatible with the thoracic anatomical constraints. All of these results allow us to envision a total implantation of the cardiac exoskeleton into the patient