Author + information
- Received January 21, 1991
- Revision received April 24, 1991
- Accepted June 23, 1991
- Published online November 15, 1991.
- Frank A. Flachskampf, MD1,
- John P. O'Shea, MBBS,
- Brian P. Griffin, MBBS,
- Luis Guerrero, BS,
- Arthur E. Weyman, MD, FACC and
- James D. Thomas, MD, FACC∗,2
- ↵∗Address for reprints: James D. Thomas, MD, Zero Emerson Place, Suit 2F, Boston, Massachusetts 02114.
The magnitude and spatial distribution of normal leakage through mechanical prosthetic valves were studied in an in vitro model of mitral regurgitation. The effective regurgitant orifice was calculated from regurgitant rate at different transvalvular pressure differences and flow velocities. This effective orifice area was 0.6 to 2 mm2for three tilting disc prostheses (Medtronic-Hall sizes 21, 25 and 29) and 0.2 to 1.1 mm2for three bileaflet valves (St. Jude Medical sizes 21, 25 and 33).
In the single disc valves, Doppler color flow examination disclosed a prominent central regurgitant jet around the central hole for the strut, accompanied by minor leakage along the rim of the disc (central to peripheral jet area ratio 3.3 ± 1.2). The bileaflet prostheses showed a peculiar complex pattern: in planes parallel to the two disc axes, convergent peripherally arising jets were visualized, whereas in orthogonal planes several diverging jets were seen.
Mounting the disc and bileaflet valves on a water-filled tube allowed reproduction and interpretation of this pattern: for the bileaflet valve, the jets originated predominantly from valve ring protrusions that contained the axis hinge points and created a converging V pattern in planes parallel to the leaflets and a diverging V pattern in orthogonal planes.
Similar patterns were observed during transesophageal echocardiography in 20 patients with a normally functioning St. Jude prosthesis. In 10 patients with a Medtronic-Hall valve, a dominant central jet was observed with one or more smaller peripheral jets. The median central to peripheral jet area ratio was 5 to 1.
In summary, in two types of mechanical valve prostheses, effective leakage orifice areas are reported and criteria proposed for the differentiation of “physiologic” and pathologic regurgitation based on the spatial configuration of the jets.
↵1 Dr. Flachskampf was supported by a grant from the Deutsche Forschungsgemeinschaft, Bonn, Germany.
↵2 Dr. Thomas is supported by the Bayer Fund for Cardiovascular Research, New York, New York.
☆ This work was supported by Grant 13-532-867 from the American Heart Association, Massachusetts Affiliate, Inc., Needham, Massachusetts.
☆☆ This study was presented in part at the 39th Annual Meeting of the American College of Cardiology, March 18–22, 1990, New Orleans, Louisiana.
- Received January 21, 1991.
- Revision received April 24, 1991.
- Accepted June 23, 1991.