What are the differences between mechanical and bioprosthetic replacement valves for tetralogy of Fallot (TOF)?

Updated: Nov 13, 2018
  • Author: Shabir Bhimji, MD, PhD; Chief Editor: Yasmine S Ali, MD, FACC, FACP, MSCI  more...
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Once the decision has been made to perform the surgery, the next step is to select the type of prosthetic valve. Because the right side of the heart and pulmonary artery vessels are a low-flow system, insertion of a mechanical prosthetic valve is associated with a very high risk of thrombosis. Patients will require lifelong anticoagulation, which also exposes them to a risk of bleeding in case of trauma. In addition, women who become pregnant may not be able to receive warfarin because of its teratogenic effects. [28]

Most often, surgeons implant a bioprosthetic valve, of which two types are available: human tissue (homografts) or animal tissue (bovine pericardium or porcine heart valve). Both types of  valves can be implanted as solo valves or as part of a conduit in the RVOT.

Although bioprosthetic valves eliminate the need for lifelong anticoagulation, they are not durable in young patients, which is a major concern. Most adults with tetralogy of Fallot are still young (second or third decade of life). In addition, nearly 40-55% of bioprosthetic valves fail within the first decade after implantation, almost guaranteeing that an otherwise healthy 30-40-year-old patient will need to undergo one or more open heart procedure(s) in the future, which also increases the risk of complications.

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