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Erschienen in:
26.05.2016 | Original Article
Opening–closing pattern of four pericardial prostheses: results from an in vitro study of leaflet kinematics
Erschienen in: Journal of Artificial Organs | Ausgabe 4/2016
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Pericardial and porcine stented aortic valves have different leaflet kinematics. To study the biomechanics of a prosthesis thoroughly, the in vitro setting is the most appropriate. The aim of our study was to find out whether the prosthesis design in which the pericardial sheet is outside the stent post might influence the opening and closing patterns of the leaflets. Four pericardial prostheses (Magna Ease [MG] 21, Trifecta [TRI] 21, Soprano-Armonia [SA] 20 and Mitroflow [MF] 23) that fitted aortic roots with a native annulus diameter of 2.1 cm were implanted and their leaflet kinematics was studied by a high-speed digital camera. In the opening phase, MG showed the shortest RVOT and the highest RVOVI, with values of 12 ± 2 and 209 ± 17 ms, respectively. The RVOT of MG was significantly shorter than that of MF (p < 0.01), but not than that of TRI (p = 0.286). Both TRI and SA showed similar opening patterns (TRI: RVOT of 15 ± 3 ms and RVOVI of 132 ± 25 ms; SA: 17 ± 2 ms and 126 ± 19 ms), without statistically significant difference. Conversely, MF showed the slowest profile, with an RVOT of 23 ± 3 ms and an RVOVI of 94 ± 8 ms (Table 1; Fig. 3). The opening/closing profile is not influenced by the position of the pericardial leaflets, but depends on other intrinsic structural characteristics related to the material used for the stent and leaflets. Moreover, the kinematics does not affect the valve performance.
Table 1
Kinematics and hydrodynamic results, reported as means and standard deviations, evaluated over the tested heart samples
TRI | SA | MG | MF | ANOVA | TRI versus SA | TRI versus MG | TRI versus MF | SA versus MG | SA versus MF | MG versus MF | |
|---|---|---|---|---|---|---|---|---|---|---|---|
p Value |
p Value |
p Value |
p Value |
p Value |
p Value |
p Value | |||||
ET (ms) | 1.0 | 1.0 | 1.0 | 1.0 | |||||||
RVOT (ms) | 15 ± 3 | 17 ± 2 | 12 ± 2 | 23 ± 3 |
<0.01
| 1.0 | 0.286 |
<0.01
|
0.03
|
<0.01
|
<0.01
|
SVCT (ms) | 247 ± 14 | 231 ± 15 | 256 ± 26 | 241 ± 11 | 0.170 | 0.463 | 0.853 | 0.931 | 0.213 | 1.0 | 1.0 |
RVCT (ms) | 35 ± 19 | 52 ± 13 | 32 ± 17 | 52 ± 4 | 0.07 | 0.474 | 1.0 | 0.494 | 0.236 | 1.0 | 0.247 |
TVCT (ms) | 283 ± 10 | 283 ± 19 | 289 ± 10 | 293 ± 11 | 0.584 | 1.00 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
RVOVI (ms−1) | 132 ± 25 | 126 ± 19 | 209 ± 17 | 94 ± 8 |
<0.01
| 0.959 |
<0.01
|
0.02
|
<0.01
| 0.07 |
<0.01
|
SVCVI (ms−1) | −0.9 ± 0.3 | −1.1 ± 0.4 | −0.57 ± 0.1 | −0.55 ± 0.1 |
<0.01
| 1.0 | 0.353 | 0.292 |
0.045
|
0.04
| 1.0 |
RVCVI (ms−1) | −16 ± 4 | −10 ± 2 | −18 ± 6 | −10 ± 1 |
<0.01
| 0.396 | 1.0 | 0.513 |
0.025
| 1.0 |
0.03
|
Δp (mmHg) | 6.7 ± 3.6 | 10.6 ± 5.5 | 15.2 ± 7.9 | 10.7 ± 6.1 |
<0.01
|
0.01
|
<0.01
|
0.01
|
0.04
| 1.0 |
<0.01
|
EOA (cm2) | 2.2 ± 1.2 | 1.7 ± 0.9 | 1.5 ± 0.8 | 1.7 ± 0.9 |
<0.01
|
0.03
|
<0.01
|
0.01
| 0.261 | 0.617 | 0.11 |
El % | 7.3 ± 1 | 11.9 ± 1 | 15.4 ± 2 | 11.8 ± 3 |
<0.01
|
<0.01
|
<0.01
|
<0.01
|
0.04
| 1.00 |
0.03
|
CO (L/min) | 3.1 ± 0.4 | 2.8 ± 0.5 | 3.1 ± 0.3 | 3.0 ± 0.5 | 0.534 | 0.282 | 0.792 | 0.702 | 0.106 | 0.552 | 0.559 |