Introduction: Opening and closing characteristics differ between porcine and pericardial valve
substitutes. The following in vitro study investigates, how these differences affect
hemodynamic performance and leaflet movements in different simulated clinical situations.
Methods: Edwards Perimount Magna (n=5) and Medtronic Mosaic Ultra (n=5) aortic valves (23mm
diameter) were investigated in a pulse duplicator. Leaflet kinematics were visualized
with a high-speed camera (3000 frames/s) at normal cardiac output (CO) (5 l/min, 70
beats/min (BPM), in an exercise state (CO 8 l/min, 150 BPM) and a low output situation
(CO 2.5 l/min, 130 BPM).
Results: Table 1 summarizes the results. Transvalvular pressure gradients were lower, but
closure volume significantly larger for pericardial valves leading to an equivalent
total energy loss. Leaflet opening and closing times were shorter for porcine valves
especially with low stroke volume.
|
|
Perimount
|
Mosaic
|
Perimount
|
Mosaic
|
Perimount
|
Mosaic
|
|
|
70 BPM, 5l/min
|
150 BPM, 8l/min
|
130 BPM, 2.5l/min
|
|
Gradient (mmHg)
|
10.7±1.2
|
14.3±1.1
|
8.5±1.3
|
11±1.2
|
2.4±0.5
|
3.4±0.4
|
|
Closure Volume (% of stroke volume)
|
7.2±1.4
|
1.8±0.4
|
5.3±1.2
|
1.3±0.2
|
13±3
|
5.7±1.2
|
|
Total Energy Loss (%)
|
8.9±1.4
|
9.0±1.5
|
8.0±1.3
|
8.2±1.2
|
7.7±1.2
|
6.7±1.3
|
|
Opening Time (msec)
|
48±10
|
27±6
|
38±11
|
27±5
|
54±12
|
30±8
|
|
Closure Time (msec)
|
111±12
|
74±10
|
68±11
|
48±8
|
86±15
|
53±9
|
Conclusion: Perimount Magna pericardial valves demonstrated lower transvalvular pressure gradients
compared to the Mosaic porcine prosthesis. However, opening and closure was prolonged
in the pericardial valves leading to an increase in closing volume especially in the
hemodynamically critical low output situation with a small stroke volume.
