Valve Replacements

Tissue Valves

An homograft is obtained from cadavers and may either be aortic or pulmonary valve tissue. It is sterilised and thus is non viable. It degenerates with time and will not grow.
An autograft is obtained from within the patients own heart. An example is the Ross operation where the pulmonary valve is removed and placed in the aortic position. A homograft is used to restore RV to PA continuity.
A xenograft is obtained from another species. The commonest organism used is the pig. The valve is removed form the pig heart and place on a stent which is sewn into the heart. An example is the Hancock valve.

All tissue valves deteriorate with time and become both stenotic and regurgitant as part of the process of rejection of any foreign body. They may also become too small due to patient growth. When this has a significant haemodynamic effect upon the heart they are replaced. They are usually easily seen on CXR as over time they calcify.

Mechanical Valves

The commonest implanted valve is “St Jude’s”. This is made from carbon (and is thus radio-lucent). It has two tilting leaflets with a low profile and thus resistance to flow. It may be used in either the mitral or aortic positions. Anticoagulation with warfarin is necessary.

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Tissue Valves

Mechanical Valves

This page was last edited 14/2/2004

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