Exploring two innovative bioengineered solutions and their effectiveness in managing valvular heart disease.
Before proceeding, please note that this article does not constitute medical advice. If readers experience any unusual symptoms, it is advisable to seek professional medical guidance. The purpose of this article is purely informational and not persuasive.
The heart is an intricate and vital organ that sustains the lives of humans and many other organisms. Its role in blood transportation supports life as it circulates essential nutrients and oxygenates the body’s cells. Interestingly, without CPR, permanent brain damage could occur in less than ten minutes.
The heart’s structure is crucial to its function in efficiently pumping blood. Comprising four hollow chambers and four valves, almost like doors between chambers, arteries, and veins, the heart plays a vital role in facilitating blood circulation throughout the body while maintaining proper heart rate and blood pressure.
Heart valves are made of a specialized set of cells and have a differing number of leaflets (flaps that open and close) depending on their function. The heart’s four valves are listed below:
Tricuspid Valve (3 leaflets), transports blood from the right atrium (patient) to the right ventricle
Pulmonary Valve (3 leaflets), transports blood from the right ventricle to the pulmonary arteries
Mitral Valve (AKA Bicuspid, 2 leaflets), transports blood from the left atrium to the left ventricle
Aortic Valve (3 leaflets), transports blood from the left ventricle to the aorta, and the rest of the body
However, valves can deteriorate over time. Valvular heart disease (VHD) occurs when valve tissue becomes damaged, often impeding blood flow from one chamber to another. For instance, stenosis results from thickened valve tissue, reducing blood flow from one chamber to another. The accumulation of tissue damage can lead to long-term effects, including heart attacks and heart disease, as restricted blood flow elevates heart rate and blood pressure.
If the condition is not as severe as stenosis, surgical repair may often be an appropriate option. However, when the case surpasses surgical repair, using bioengineered artificial heart valves becomes imperative to replicate a healthy valve’s function and prolong the viability of the patient’s heart. Depending on the scenario, a patient can receive two types of valves:
Mechanical (Metal) Valve
Usually lasts for a lifetime
Made up mainly of carbon but also comprised of metal
Key advantage(s): Very durable and usually does not require surgery after implantation
Key disadvantage(s): Mechanical valves cause blood clotting, so they require anticoagulation, or the ingestion of a blood thinner (Coumadin/Warfarin) to avert blood clotting inside the heart. Finally, a slight clicking noise can be observed when the valve opens and closes
Anticoagulants worsen the management of any epithelial damage or superficial injuries. Bleeding may occur abnormally, so blood thinner monitoring is required to ensure the patient is in a healthy range.
2. Bioprosthetic (Biological) Valve
Tissue to create the valve comes from pigs or cows
Key advantage(s): Does not require anticoagulants since blood clotting does not occur
Key disadvantage(s): Wears out much easier compared to metal valves, and lasts around 10–20 years. Less effective than mechanical heart valves in promoting blood flow
Valve replacement does not usually require surgery: a catheter can be inserted and inflated to fit a new valve precisely into the previous valve’s zone
So, which is better? Well, it depends on the patient.
If you lead a less active lifestyle and are willing to undergo anticoagulant therapy and regular blood volume monitoring without concern for surgical procedures, then mechanical valves might be appropriate.
However, if you are active and prone to bruising, mechanical heart valves may not be the optimal choice since anticoagulants could thin your blood and lead to adverse health outcomes.
Age is a significant factor to consider in choosing the appropriate type of heart valve. For middle-aged patients, mechanical heart valves may be preferred, providing the advantage of not requiring further surgery for the remainder of their lives. In contrast, elderly patients may find bioprosthetic heart valves more suitable, as they typically last around 10 years, aligning better with their remaining lifespan and removing the need for blood thinner medication.
References:
HeartValveSurgery.com. (2023, October 27). Mechanical or Bioprosthetic Heart Valves: Which Is Best For You? [Video]. YouTube. https://www.youtube.com/watch?v=lVymPXiZRSw
Zero to Finals. (2018, November 30). Prosthetic Heart Valves: Visual Explanation for Students [Video]. YouTube. https://www.youtube.com/watch?v=4CaVrBv_Adg
David T. (2021). How to Decide Between a Bioprosthetic and Mechanical Valve. The Canadian journal of cardiology, 37(7), 1121–1123. https://doi.org/10.1016/j.cjca.2020.09.011