Pericardial heart valves

Pericardial heart valves are a type of artificial heart valve used in heart valve surgery to replace diseased or dysfunctional heart valves. These valves are made from the pericardium, the membrane enclosing the heart. The pericardium of cows (bovine) or pigs (porcine) is often used in the construction of these valves due to its durability and biocompatibility. Pericardial heart valves are designed to mimic the function of natural heart valves, ensuring unidirectional blood flow through the heart's chambers.

History

The development of pericardial heart valves began in the mid-20th century, as a response to the limitations of mechanical heart valves and earlier versions of bioprosthetic heart valves. Mechanical valves, while durable, require patients to take lifelong anticoagulants to prevent blood clots. Early bioprosthetic valves, made from pig aortic valves, had better hemodynamics but were less durable. Pericardial valves were introduced to combine the durability of mechanical valves with the physiological benefits of bioprosthetic valves.

Design and Function

Pericardial heart valves are constructed by shaping and fixing the pericardial tissue onto a synthetic or metal frame. This frame is then sewn into the patient's heart during surgery. The design of these valves aims to reduce turbulence and wear on the tissue, extending the valve's lifespan and improving patient outcomes.

The function of pericardial heart valves is to facilitate the flow of blood in the correct direction through the heart, similar to the natural valves they replace. They open and close in response to the pressure changes within the heart's chambers during the cardiac cycle.

Advantages and Disadvantages

Advantages of pericardial heart valves include their resistance to calcification, which is a common cause of bioprosthetic valve failure. They also tend to have better hemodynamic performance, meaning they can handle blood flow more efficiently than other types of valves. This can lead to improved quality of life and reduced symptoms for patients.

However, pericardial heart valves are not without their disadvantages. They may still undergo structural deterioration over time, leading to potential valve failure and the need for replacement. Additionally, while the risk of blood clot formation is lower than with mechanical valves, it is not entirely eliminated.

Surgical Procedure

The replacement of a heart valve with a pericardial heart valve is performed under general anesthesia through open-heart surgery. The procedure involves making an incision in the chest, stopping the heart temporarily, and placing the patient on a cardiopulmonary bypass machine, which takes over the function of the heart and lungs during the surgery. The diseased valve is removed, and the pericardial valve is sewn into place.

Postoperative Care

After surgery, patients will require monitoring in the hospital to ensure the new valve is functioning properly. Long-term, patients may need to take medications to prevent infection (antibiotics) and, in some cases, medications to prevent blood clots. Regular follow-up appointments with a cardiologist are necessary to monitor the performance of the valve and the overall health of the heart.

Conclusion

Pericardial heart valves represent a significant advancement in the field of heart valve replacement, offering an option that combines the durability of mechanical valves with the physiological compatibility of bioprosthetic valves. While they are not without their challenges, these valves have improved the quality of life for many patients with heart valve disease.