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at high vs. low pressure.
65
The study revealed a lower rate of structural valve
deterioration in the low pressure fi xation group. Patient age at implantation
proved to be another important determinant of valve durability; valve
deterioration was lower in patients over 65 years old.
Jamieson
et al.
66
reported on a series of 1823 CE supra-annular aortic
porcine implants with a 20 year follow-up. The overall actuarial survival was
28.8
2.0% at 20 years. The overall freedom
from structural valve deterioration in all age groups was 64% at 18 years,
but in patients
±
1.5% at 15 years and 6.8
±
≥
70 years of age was even higher, 95%, at 18 year
follow-up.
4.4.4 Medtronic Mosaic porcine bioprosthesis
The Medtronic Mosaic porcine bioprosthesis (Fig. 4.11) represents the third
generation of the Porcine Hancock Bioprosthesis, and evolved after mul-
tiple refi nements to improve its function and durability. The use of amino-
oleic acid, an anti-mineralization agent, and low pressure fi xation with
glutaraldehyde has helped to preserve the collagen structure of the leafl ets.
The valve is mounted on a fl exible homopolymer stent that decreases the
commissural stress during valve closure. The sewing ring for the aortic posi-
tion has a scalloped shape that facilitates supra-annular valve implantation.
Both the aortic and mitral Medtronic valves have lower profi les than the
older Hancock valve.
4.11
Medtronic Mosaic porcine prosthesis, the third generation of the
Hancock porcine tissue valve. Image presented with permission of
Medtronic, Inc., Minneapolis, MN, USA.
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