Hemodynamic Data


On-X Valve Echo Presentation


On-X valve data from MCRI Application to United States Food & Drug Administration for Premarket Approval (P000037), September 1, 2000 updated to July 1, 2001. (301 patients, 838 pt-yrs):


Aortic Echocardiography

Peak Gradient








Aortic Figure 1. Peak gradients are an important consideration for active patients. The peak gradient values early and late (>1 year postoperation) are shown here.

Mean Gradient








Aortic Figure 2. Mean gradients for patients at rest are 11.6 for the 19 mm valve early and decreasing to single digit values late.









Aortic Figure 3. The effective orifice areas rise from 1.5 cm 2 for the size 19 valve to near 3 cm 2 for the larger sizes.









Aortic Figure 4. The superior hemodynamics of the On-X valve results in a substantial decrease in left ventricular mass.








Aortic Figure 5. The indexed EOA (effective orifice area divided by body surface area) is about 0.9 for the 19mm valve and increases with valve size.








Aortic Figure 6. This chart shows that the On-X aortic valve can support a substantially larger person than other brand valves of the same size.


Mitral Echocardiography


Mitral Peak Gradiant Comparison








Mitral Figures 7 and 8. Among different brands and sizes of mitral valves, the mean and peak gradients are indistinguishable in magnitude even though the orifice areas are substantially different. In other words, the gradients are independent of the orifice area.

Mitral Mean Gradiant








Mitral Figure 8.

Mitral Effective Oriface Area








Mitral Figure 9. It can be seen here that, like the mean and peak gradients, the effective orifice area is independent of valve size.

Geometric Orifice Area Comparison








Mitral Figure 10. The above data compared with the geometric orifice area (GOA) shown here lead to an interesting conclusion. As shown above, the mean and peak gradients and the EOA are essentially independent of the geometric orifice area. The smallest of the compared valves has a GOA equivalent to an On-X valve size 21. The conclusion is that with mitral valves, pressure losses are controlled not by valve size but by other physiological limitations.


  1. Figs. 1-4: Chambers John C, Ely John L. Early and Late Echocardiographic Performance of the On-X AorticValve, presented at “Advances in Cardiac Surgery 2001” in San Diego, CA, May 5, 2001.
  2. Fig. 5: Food and Drug Administration clinical trial from September 1, 2000 updated through July 1, 2001 (2.8 year mean follow-up).
  3. Fig. 6: 1 PMA Summary of Safety and Effectiveness, Food and Drug Administration, May 30, 2001. 2 Chafizadeh R, et al. Doppler Echocardiography assessment of the St. Jude Medical Prosthetic Valve in the aortic position using the continuity equation. Circulation 1991;83:213-223. 3 PMA Summary of Safety and Effectiveness, Food and Drug Administration, September 29, 1993. 4 PMA Summary of Safety and Effectiveness, Food and Drug Administration, October 13, 2000.
  4. Figs. 7-10: References available from On-X Life Technologies, Inc.

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