Choosing the Right Valve Prosthesis

There are valve prostheses for each type of heart valve, i.e. four types of prostheses:

• Aortic prostheses: Aortic valve prostheses are used to repair the aortic valve at the junction between the heart and the aorta. The aorta is the main artery of the human body, carrying blood from the heart to all parts of the body, excluding the lungs.
• Mitral prostheses: These are used to repair or replace a patient’s native mitral valve. The mitral valve is one of the heart’s main valves, allowing blood to pass from the left atrium (which receives oxygenated blood from the lungs) to the left ventricle (which pumps blood to the aorta and vital organs).
• Pulmonary prostheses: Pulmonary valve prostheses are used to replace native pulmonary valves (congenital or acquired lesions) or damaged or defective prosthetic valves. The pulmonary valve transfers blood from the right ventricle to the pulmonary artery. It divides into two arteries to supply blood to both lungs.
• Tricuspid prostheses: Tricuspid valve prostheses are used to repair a defect in the tricuspid valve. It lies between the heart’s right atrium and right ventricle, opening when the atrium contracts and closing when the ventricle contracts.

Medtronic mitral or aortic bioprosthesis

There are two main types of valve prostheses: mechanical and bioprosthetic.

• Mechanical prostheses:
  • Advantages:
    • High reliability: These are the oldest prostheses, made from pyrolytic carbon and titanium. They are solid and offer excellent hemodynamics.
    • Increased durability: Mechanical prostheses last longer than bioprostheses.
  • Disadvantages:
    • Lifetime anticoagulant treatment required: These prostheses require lifelong anticoagulant treatment. Without this treatment, clots can form, posing a risk of embolism, particularly in the brain. Anticoagulant treatment is restrictive, as it requires regular monitoring of its efficacy. If the dosage is inadequate, the patient may be prone to hemorrhage if over-anticoagulated, or prone to cerebral, peripheral, or pulmonary embolism if under-anticoagulated.
• Bioprostheses:
  • Advantages:
    • Minimally invasive surgery: These prostheses are made of a part of animal tissue (porcine valve or bovine pericardium), which makes them more flexible and therefore implantable in minimally invasive surgery.
    • No anticoagulant treatment: These prostheses are more biocompatible and therefore do not require long-term anticoagulant treatment.
  • Disadvantages:
    • Less resistant: Bioprostheses need to be replaced, unlike mechanical models, which do not.
    • Limited durability: They have a more limited lifespan than mechanical prostheses, ranging from 10 to 15 years for mitral bioprostheses and 20 to 25 years for aortic bioprostheses. In children, they only last between 3 and 5 years and are therefore no longer used.

Abbott Vascular metallic aortic valve prosthesis

Here are the fixation methods suitable for the two main types of valve prosthesis mentioned in question 2.

• Mechanical prostheses: Mechanical prostheses are sutured prostheses (fixed with sutures), which means:
  • More extensive surgery is required to implant them, with longer procedural times (clamping, anesthesia) and hospital stays.
  • Lifelong anticoagulant treatment is needed immediately after the operation.
• Bioprostheses: The most recent models of bioprostheses use other fixation methods and are known as “sutureless”. They are fixed by a self-anchoring system, or mounted on a self-expanding stent or a balloon-expandable stent. These sutureless valves offer these advantages:
  • Minimally invasive surgery, because they are self-extending and installed by catheterization.
  • Taking anticoagulants is not required after the operation.

Today, new fixation methods are being studied for certain bioprostheses, such as a fixation model placed directly on a previously implanted bioprosthesis (for bioprosthesis replacements).

Here is some additional information to help you choose between mechanical and bioprosthetic valve prostheses.

• Mechanical prostheses:
  • Generally suitable for patients under 60 years of age (aortic valves) or under 65 years of age (mitral valves).
  • Generally suitable for patients under 40 years of age with an accelerated risk of structural deterioration of the heart valves.
• Bioprostheses:
  • Generally suitable for patients aged 65 to 70 and over due to the ratio of bioprosthesis lifespan to life expectancy.
  • Generally suitable for pregnant women and women of childbearing age, to avoid the teratogenic risks of anticoagulant treatment. It is also difficult to define the dosage of this treatment during pregnancy because of the variation in blood volume.
  • Generally suitable for patients already on anticoagulant treatments, to avoid changing dosages, or for patients unable to access regular anticoagulant treatment for economic, social, geographical, or other reasons.

Corcym sutureless aortic valve bioprosthesis