Proof of Concept: Measuring Aortic Annulus Resistance by Means of Pressure-Volume Curves During Balloon Inflation to Guide Transcatheter Aortic Valve Implantation

This study assessed the basic working principle to measure aortic annulus resistance during balloon inflation for transcatheter aortic valve implantation (TAVI), by acquisition of pressure-volume curve for a guided semi-automatic implantation. A modular bench-system was used which allows the incremental inflation of valvuloplasty balloons by means of a stepper-motor driven linear axis with simultaneous recording of the pressure changes inside the system. Different porcine aortic xenografts were assessed by use of a non-compliant valvuloplasty balloon. In a second step transcatheter aortic stents were implanted inside target sized xenografts. The recorded pressure volume-curves showed that the system can accurately differentiate between different xenografts and assess the quality of the tissue rendering real-time analysis of pressure-volume curves during balloon-inflation possible, which has the potential to optimize the implantation procedure by direct adaptation to the patient specific anatomy and characteristics. Further investigations and development are warranted

Objektorientiert-modellbasierte Charakterisierung, Überwachung und Regelung des technisch unterstützen Herz-Kreislauf-Systems

This thesis focusses on methods that allow direct use of object-oriented modelling within model-based control concepts. Object-oriented modelling has so far been used primarily in simulation. However, the benefits of object-oriented modeling can also simplify and speed up the design process of model-based control methods. The cardiovascular system, which is technically supported by a blood pump, is considered as the focus of application of these methods. Considering current trends of increasing digitization and networking in medicine, various approaches are conceived within the work, which expand the treatment options of technical heart support, as well as make them safer and more efficient. To implement the methods in practice, a research platform consisting of various software and hardware components was developed within this thesis. The research platform constitutes an animal experimental based prototype of a highly digitized and networked surgical or intensive care treatment environment and allows for the simple online application of higher control strategies. In addition, a comprehensive experimental database was set up for the automated evaluation of large amounts of data. In various clinically relevant application examples, the methods are examined in simulation as well as in vivo. The applications cover various aspects of characterization, monitoring and control of the technically supported cardiovascular system. In addition, the thesis also includes the design and initial evaluation of a conceptually new heart assist device

A Hybrid Mock Circulation for Control Algorithms of Ventricular Assist Devices

This paper deals with the design, simulation and control of a new lightweight hybrid Mock-Loop (MCL) concept. The proof of concept is evaluated by two simulation approaches. First, the design parameters are chosen by an optimal control problem. Second, a cascading controller structure is evaluated in a simulation. Both show that with a suitable range of the design parameter the new lightweight concept can be used as a MCL. To validate these findings, further investigations with the MCL under realistic test conditions are required