Education & Fellowships
Cardiothoracic Surgery Service
LAC+USC Medical Center Student Handout
Selecting A Cardiac Valvular Prosthesis
A cardiac valvular prosthesis can be either mechanical (metal) or biologic (xenograft) or from a cadaver (homograft). The advantage of a mechanical prosthesis is that it may last for a lifetime but requires anticoagulation and its possible complications. The benefit of utilising a bioprosthetic is that anticoagulation is not needed but at approximately 8-10 years the valve degenerates to the point where it must be replaced. The homograft which is a cryopreserved cadaver valve has good longevity and does not require anticoagulation but their availability and cost is its major limiting factor.
A Mechanical Prosthesis is utilized for children, adults 18-65 years old without a contraindication for anticoagulation.
- Coumadin anticoagulation is required to keep an INR from 2-3. IV heparin may be needed until the oral anticoagulation level is reached.
- This type of prosthesis should not be used in patients of childbearing age or in those who have a contraindication to anticoagulation (h/o GI bleeding, h/o CVA), it may be utilized in those who already have a requirement for anticoagulation (h/o PE, chronic atrial fibrillation).
- In case of poor anticoagulation and thrombosis of the valve, a catastrophic event will be the first signal - total hemodynamic collapse.
A Bioprosthetic is utilized in patients who have a contraindication to coumadin, women who wish to give birth to children, elderly, those whose life expectancy will not be long (cancer patients).
- The major problem is wear and tear, replacement may be needed in 5-10 years.
- Endocarditis will affect these valves like a native valve. The sterilization with antibiotics of a bioprosthetic is no easier than a mechanical valve.
- The destruction of these valves by endocarditis will result in progressive regurgitation and CHF.
New Valves: There are new porcine valves on the market for aortic valve replacement. Available are the StJude Medical Toronto stentless porcine valve and there is also the Medtronic Free Style valve. Both seem to have reliable outcomes for at least 6-7 years after implantation. It remains to be seen whether they will prove out well in the future. Anticoagulation is needed or recommended for 6 weeks.
Ross Procedure: Excision of the aortic valve, harvesting of the pulmonic valve and the right ventricular outflow tract and implanting it into the aortic position. The pulmonary valve is then replaced with a cadaver homograft. This is autologous tissue and there is also no need for anticoagulation. It is a good choice for young patients or children. More info...
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