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If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.
What are mechanical heart valves?
Your heart is one of the hardest working muscles in the body—it is responsible for pumping oxygen-rich blood throughout the body and bringing oxygen-poor blood back to the lungs for an oxygen refill. For this reason, your heart has four chambers (left atrium, right atrium, left ventricle, right ventricle) and four one-way valves. These valves guide the flow of blood through the heart and prevent blood from moving backward.
- Tricuspid valve: maintains the flow from the right atrium into the right ventricle
- Pulmonary valve: maintains the flow from the right ventricle into the pulmonary artery (the artery that takes blood to the lungs to get reoxygenated)
- Mitral valve: maintains the flow from the left atrium into the left ventricle
- Aortic valve: maintains the flow from the left ventricle into the aorta (largest artery leaving the heart)
Sometimes the heart valves can malfunction—this called valvular heart disease (VHD). VHD most commonly affects the aortic and mitral valves. There are three main ways that your heart valves can malfunction:
- Regurgitation (or insufficiency): In regurgitation, the valve does not close properly, and blood leaks backward. Types include mitral regurgitation and aortic regurgitation.
- Stenosis: Stenosis occurs when the valve leaflets are either fused or too stiff to open entirely. This makes the opening more narrow and decreases blood flow. Types include mitral stenosis and aortic stenosis.
- Atresia: Atresia is the least common of these three and is the result of a poorly developed heart valve that does not have an opening for blood to flow through. It presents at birth and is a type of congenital heart defect.
Valvular heart disease is often treated initially with medications and lifestyle modifications. Unfortunately, some people’s valvular malfunction worsens to the point that they need to have surgery to either repair or replace the damaged heart valve. This decision involves a discussion with your healthcare provider regarding the severity of your valve disease, whether you need heart surgery for other reasons, and your overall health. A heart valve is repaired rather than replaced whenever possible. Unfortunately, heart valve repair is more challenging, and not all valves can be repaired. Once the decision is made to undergo heart valve replacement, you and your team of healthcare providers will discuss which type of prosthetic heart valve is the best option for you. This is a shared decision because it can have lifelong implications. Heart valve replacement involves removing the dysfunctional valve and replacing it with either a mechanical valve or a biological valve.
Mechanical valves are usually made from titanium or carbon and are designed to mimic the original valve. They can be used for aortic valve or mitral valve replacement (Harris, 2015). Most mechanical valves come in one of two shapes: monoleaflet or bileaflet. The monoleaflet valves have a single disk that tilts to open, an example of which is the Medtronic Hall valve (Gaasch, 2019). The bileaflet valves (e.g., St. Jude Medical, Carbomedics, and On-X valves) have two discs that can open on hinges (Gaasch, 2019). Mechanical valves are long-lasting (usually 20–30 years) and may last the rest of your lifetime (Tillquist, 2011). That being said, people with mechanical heart valves need to take lifelong blood-thinning medications (like warfarin) because the valves provide a place for blood clots to form (Harris, 2015). For this reason, most cardiologists do not recommend mechanical heart valves in women of child-bearing age, people prone to falls, or those at high risk for bleeding (Harris, 2015).
Mechanical valves are recommended for certain people based on patient preference, the ability to take blood thinners, other medical conditions you may have, among other factors. In general, younger patients (less than 55 years old) often opt for the mechanical valve because of how long it lasts. As mentioned, you also need to be healthy enough to take lifelong anticoagulation (blood-thinning) medications.
Potential risks of mechanical valves
The main downside of mechanical heart valves is the need for lifelong anticoagulation. The movement of blood through the valve activates platelets and increases the risk of a blood clot forming. You, therefore, need the blood-thinners (Tillquist, 2011). While anticoagulants help you by decreasing the chance of clots, they also make it more likely that you are going to have abnormal bleeding. Also, the chance of bleeding goes up as you age; people over age 60 with mechanical valves on anticoagulation are almost seven times more likely to bleed than a similar patient who is younger than 60 years old (Tillquist, 2011). In addition to the risks of blood clots or bleeding, there is a risk that the valve can become infected, which is called endocarditis. People with mechanical heart valves require close follow up of their anticoagulation therapy.
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Other heart valve options
If you are not a candidate for (or do not want to have) a mechanical heart valve, there are other options, namely biological valves. One option is a donor heart valve that comes from a human donor. These are rarely used and are reserved for people who are suffering from a heart condition called infective endocarditis. More commonly, bioprosthetic valves (tissue valves) are the option of choice. Bioprosthetic valves usually come from bovine (cow) or porcine (pig) tissue. They typically last about 10–20 years, so not as long as mechanical valves (Tillquist, 2011). Since they don’t last as long, there is a higher chance that you will need a reoperation to replace the tissue valve. This is one reason that bioprosthetic valves are often more appealing to older people or people with a shorter life expectancy. However, the upside is that bioprosthetic valves have a lower chance of forming blood clots, so you don’t have to take lifelong blood-thinners. This makes bioprosthetic valves a good option for people who are not able to take anticoagulants or who are at a high risk of bleeding. Some people may be candidates for a transcatheter aortic valve replacement (TAVR) with a biologic valve; this procedure allows the surgeon to replace the aortic valve through a flexible tube (catheter) rather than a large chest incision.
For some people, despite taking their medications and adopting the recommended lifestyle changes, their valvular heart disease continues to progress, and the only remaining option is heart valve surgery. Talk with your cardiologist (heart specialist) about your options for valve replacement. By discussing the risks and benefits, you can make an informed decision that will impact your long-term health.
- Gaasch, W. H. & Suri, R. M. (2019, April 12). UpToDate. Prosthetic Valve Types. Retrieved Feb. 4, 2020 from https://www.uptodate.com/contents/choice-of-prosthetic-heart-valve-for-surgical-aortic-or-mitral-valve-replacement#H2441809857
- Harris, C., Croce, B., & Cao, C. (2015). Tissue and mechanical heart valves. Annals of Cardiothoracic Surgery, 4(4), 399. doi: 10.3978/j.issn.2225-319X.2015.07.01. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/26309855
- Tillquist, M. N. & Maddox, T. M. (2011). Cardiac crossroads: deciding between mechanical or bioprosthetic heart valve replacement. Patient Preference and Adherence, 5, 91–99. doi: 10.2147/ppa.s16420. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/21448466
Dr. Mike is a licensed physician and the Director, Medical Content & Education at Ro.