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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 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.
- 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.
- Fig. 5: Food and Drug Administration clinical trial from September 1, 2000 updated through July 1, 2001 (2.8 year mean follow-up).
- 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.
- Figs. 7-10: References available from On-X Life Technologies, Inc.