While bi-leaflet mechanical heart valves have been in development for many years, significant room for improvement remains in their non-physiological hemodynamics, as their current performance is still damaging to red blood cells.
One proposed improvement for MHVs is to increase their ovality. They are currently manufactured to be circular but by slightly increasing their ovality, their shape can closely match the natural shape of heart valve annuli. Another area for improvement is in the leaflet shape, current designs rely on two semicircular leaflets that extend directly through the center of the valve’s lumen. This results in undesirable hemodynamics and the shear stresses induced require the constant use of anticoagulants to prevent fatal thrombus formation.
The animation above depicts a mechanical heart valve designed right here in the Heart Valve Performance Laboratory, the Apex Valve. The unique shape of the leaflets allows them to open against the inner surface of the housing, providing an unmatched effective orifice area and unobstructed flow through the center of the valve’s lumen.
In the image to the left, a comparison can be seen of the valve in the open position and of the housing with no leaflets in place. This demonstrates how significant the opening of the valve is with the leaflets moving entirely out of the path of blood flow.
The Apex Valve is currently undergoing in vitro testing and is anticipated to be applicable for both the aortic and pulmonary positions; it is also being assessed for potential pediatric applications as well.