Tornado-Compatible Mechanical Aortic Valve Prosthesis: Experimental and Clinical Application of Tornado Technology

Currently used mechanical heart valve prostheses does not fully restore the function of the valve and require aggressive anticoagulation therapy. One of the reasons leading to the prostheses disfunction is neglecting of hydrodynamic compatibility with the blood flow pattern Studies of the hydrodynamic structure of the blood flow in the heart and aorta are being performed in the Bakulev Center for Cardiovascular surgery since 1992. It has been shown that blood flow, generated in the left ventricle corresponds to the structure of self-organizing tornado-like flows described by the exact solution of unsteady hydrodynamic equations for this class of flows, published in 1986. The previous attempts to adapt the geometry of prosthetic heart valve to the swirling blood flow were not successful since there were no any quantitative criteria of the flow structere. A new model of a mechanical aortic valve — Tornado-compatible valve (TCV) (patent RU 2434604 C1), has the lumen completely free from any kind of obstacles that could disrupt the flow pattern. The valve consists of a body and three cusps which profile is adopted both to the flow in Aorta, and to the flow in Sinuses when the valve is closed. The standard hydrodynamic testing of this valve has shown its significant advantage compared with other valve types. A special testing was developed using the original bench which generates the Tornado-like jet. For this a converging channel was worked out, which profile corresponds to the streamlines of Tornado-like flow, calculated from the exact solution. The resulted jet manifested all principal properties of Tornado: laminar “glass-transparent” jet without any visible perturbations in the flow core. Several valve types were testing using this bench. TCV did not affected the jet structure, and time of water flowing out. The valve was implanted in the pig without anticoagulant administration. According to echocardiography and coagulation control the valve function was satisfactory up to ten months of observation. In the autopsy the luminal surface of outflow part of the left ventricle, and the ascending aorta were free of thrombi and pannus formation. The clinical implantation in the patient with aortic stenosis was performed. The follow-up period is 4 years.