Hemodynamics On-X Valve Hemodynamic Data Hemodynamic Principles


Low Gradients

The On-X valve's hemodynamic performance is one of the very best among valve prostheses, particularly in smaller sizes. Table 1 compares the mean pressure gradients and maximum body surface area of the On-X valve size 19 with other competitors' valves fitting a 19mm annulus.

Table 1. Hemodynamic Performance1-8

19 mm Annulus Gradient (mmHg) EOA* (cm2) GOA** (cm2) BSA*** (m)
On-X Valve 8.3 1.5 2.0 1.76
SJM Regent 9.7 1.6 1.96 1.88
ATS 16/19 20.2 1.2 1.25 1.41
CMI Supra-annular 21 16.2 1.3 1.46 1.53
Medtronic Advantage 19 16.0 1.0 not available 1.18
Medtronic Freestyle 12.0 1.1 not available 1.29
Edwards Perimount 22 0.82 not available 0.96
*Effective Orifice Area
**Geometric Orifice Area (leaflets in place)
***Body Surface Area (accommodated without patient mismatch, based on 0.85 EOA index)


Intra-Annular Flared Walls Preserve – Hemodynamic Benefit

The On-X valve hemodynamics benefit extend beyond outstanding gradients. While many valves vacate the annulus to increase orifice area, the On-X valve extends through the annulus, protecting against ingrowth to preserve the full geometric orifice area of the valve over time.

The Thrill is Gone!

With On-X aortic valves, surgeons report an absence of a “thrill” within the aorta of implanted patients.

What Thrill?

Following implantation of an aortic valve prosthesis and removal of the cross-clamp, many surgeons pause to palpate the patient's aorta. This habit provides a tactile confirmation that the implanted valve is functioning properly. With bileaflet mechanical valves, surgeons report that they characteristically feel an unnatural “thrill” (vibration) in the aorta.

The absence of thrill with On-X valves is a further indication that efforts to reduce turbulence have met with success. On-X valves are designed to emulate the natural flow of the native valve with hemodynamic features like the inlet flare, thinner orifice walls, natural length and fully opening leaflets.

Best Overall Performance

The evolutionary new shape of the On-X valve is defined by sound fluid dynamic principles that reduce turbulence, pressure gradients and hemolysis. No other valve provides such comprehensive benefit to the patient's well-being.

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