The Effect of Aortic Valve Replacement on the Coronary Perfusion - Computational Fluid-Structure Interactions Modeling and Analysis

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Transcatheter aortic valve implantation (TAVI) is an alternative treatment to conventional surgical aortic valve replacement for patients with aortic stenosis. Patients with severe aortic stenosis suffer also from diastolic dysfunction and reduced coronary flow (perfusion). The coronary perfusion depends on the pressure gradient between the myocardial tissue during diastole and the coronary origin located at the aortic root (sinuses of Valsalva), and thus subjected to changes in diastolic flow field near the closing valve`s leaflets. Coronary perfusion can be influenced by the valve size and design as well as diastolic time.

In this study, we examine the impact of replacement valve on the coronary perfusion and on the pressure changes in the aortic root. The numerical models include 2D computational fluid-structure interaction (FSI) simulation of the aortic root including the valve`s leaflets and coronary arteries, using the commercial finite-element package of ADINA.

The study considered healthy, stenosed and TAVI valves. Pressure and flow patterns were investigated for each model. It is found that aortic valve replacement leads to a significant improve in coronary flow as well as in the cardiac cycle time. This could be explained by the pressure changes in the sinus, aorta and coronary areas. The appearance time, size and location of a circular flow located on the leaflets tip and subsequently at the sinus area has a large outcome on the aortic, sinus, coronary pressure and flow.

The results may shed light on the dynamic mechanisms that improve coronary perfusion due to TAVI.