Design and testing of Aortic test bench

Aortic valvular disease occurs when the valve between the aortic arch and the left ventricle fails to function effectively through an open and close mechanism in response to blood flow. A damaged aortic valve can be caused by aortic stenosis or aortic regurgitation. In aortic stenosis, the valve is constricted and does not fully open. This lowers or completely prevents blood flow from the left ventricle to the aorta and the rest of the body. While in aortic regurgitation permits part of the blood pumped out of the left ventricle to return. As the left ventricle works harder to maintain blood flowing through the aortic valve, it may expand and weaken. Cardiologists are eager to replace the damaged valve with a new one to address the essential issue of aortic valve failure, which can be completely invasive or less invasive, such as transcatheter aortic valve implementation, The valve replacement depends on using prosthetic or bioprosthetic valves taking into consideration the hemodynamic physiological characteristics like pressure and fluid flow. The aim of this thesis project is to design and testing of an aortic test bench for the evaluation of hemodynamic parameters of prosthetic valve of the left-sided part of the heart which in turn may be used as a guide for surgeons when replacing a damaged valve. The creation of revolutionary test benches for aortic valves resulted from the advent of new less invasive surgical procedures for heart valve implantation, as opposed to riskier open-heart surgery. The bench must meet the requirements for the ability to perform fluid dynamical and optical measurements at the aortic valve level. As a result, special materials and components are required for the bench's construction. Flat and clear plexiglass panels 2 are required to give optical access while doing optical tests. The material utilized to recreate these anatomical components is elastic, allowing the ventricle to contract and relax and the aorta to expand and rebound, much like the genuine ones. The construction of the test bench with anatomical components that are morphologically close to the genuine one might aid in obtaining a more realistic value for hemodynamic parameters, in terms of flow and pressure changes. The test takes into consideration pulsatile flow which represents blood flow in a normal cardiac cycle that passes through different compartments of the heart and the method to initiate it. For this purpose, a control system is designed and used as an engine to simulate the pulsatile flow of fluid passing through the left ventricle and aortic arch synthesized materials which are used in the realization of test bench creation. In this study, we employed a feedback linear actuator whose stroke activates the membrane of the piston pump, stimulating fluid flow via the developed system. The actuator feedback is determined by an external electromotive instrument's input signal. Both devices are equipped with a microcontroller device that takes input readings and processes them using its own software to translate analog data into physical actions. Measurement sensors including flow and pressure sensors are utilized to gather and record data from the left ventricle and aortic arch during the running of the designed bench. These recorded measurements are then captured by a data collecting system, which processes them through built-in software to display the values of studied parameters as a consequence of fluid flow during the operation of the created bench. Based on the results obtained by the measurement sensors for the pressure and flow readings during the test which are closely the physiological parameters during the cardiac cycle, the heart surgeon should be able to do the simulation immediately on the test bench before the valve implant on the patient to ensure that they satisfy all requirements in terms of the hemodynamic characteristics of the healthy valve.