Nonsymmetric leaflet motion of St. Jude Medical mitral valves simulated with a computer-controlled hydraulic mock circulator.

Since the introduction of high-performance prosthetic heart valves, particularly bileaflet valves and monoleaflet valves with larger opening angles, we have observed in vivo complex leaflet motion which has not been experimentally confirmed yet. We developed a computer-controlled hydraulic mock circulator to study the motion of in vivo leaflets. A high speed CCD camera recorded the valve movement. In the mitral position, a standard St. Jude Medical valve was tilted to be horizontal or vertical. The test valve was driven with single- or double-peaked flow. The flow rate was set to 5.0 L/min at 70 bpm with a systole/diastole ratio of 0.3. We found the following results: independent of valve orientation, the valve showed a nonsymmetric leaflet motion; the valve showed unpredictable leaflet position during decreasing flow or absence of flow; and the disc closed temporarily at the lower inflow rate between the 2 flow peaks.