Developments in cardiovascular valve technology - Biomaterials and Devices for the Circulatory System - page 97

Table 4.2 Biological valve prostheses in past or present clinical use

Manufacturer or
anatomic source

Dates of
manufacture a

No. of
implants b Valve type

Homografts Aortic 1956-discontinued -

Dura mater 1971-1974 694

Heterografts Hancock 342 1969-1977 35 000

Medtronic 1970-present -

Tascon Bio 1984-1986 24

Edwards Lifesciences 1970-present c. 1 200 000

Pericardial Ionescu-Shiley 1976-discontinued -

Edwards Life Sciences 1981-present -

Carpentier-Edwards
Perimount

1981-present -

New biological
(in trials)

Sorin Stentless 1991-present -

ATS Equine 1991-present 800

a Specifi c dates of discontinuation are given if available; all other discontinued
products are labeled as such.
b Number of implants are given only if that information is available.

Barratt-Boyes in New Zealand implanted antibiotic-sterilized aortic
homografts. 56
The development of aortic homografts has always been challenged by the
logistics of procurement, sterilization, and storage. Early attempts at storage
utilizing deep-freezing damaged the leafl ets. The best method seemed to be
chemical sterilization with antibiotic solutions. 46 Despite the use of this type
of tissue preservation, Langley et al. reported that the valve failure rate
requiring re-operation was 3.3%/year. 57 Binet and Carpenter performed
the fi rst valve replacement with a porcine aortic prosthesis that had been
preserved in 4% formaldehyde. 58 Their successes generated considerable
interest and excitement in cardiac centers around the world. Unfortunately,
these xenografts did not live up to expectations, and valve failures started
to be noted by cardiac surgeons, who reported failure rates approaching
68%. The unacceptable failure rate of the formaldehyde-fi xed valves
prompted investigators to change the preservation medium to glutaralde-
hyde. 59 This chemical proved to be an excellent medium to preserve the
natural fl exibility and durability of the valves and at the same time sterilize
the tissue. In the 1970s Barratt-Boyes suggested fi xation at extremely low
barometric pressures, instead of a high pressure fi xation method. This modi-
fi cation improved the durability of the leafl ets by affording better preserva-
tion of the leafl et collagen structure. 60

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