Hancock Aortic Tissue Valve

Hancock Aortic Tissue Valve is a type of bioprosthetic heart valve used in cardiac surgery to replace a diseased aortic valve. The valve is made from porcine (pig) heart valves, which are treated and fixed to prevent rejection by the human body. The Hancock valve was one of the first bioprosthetic valves introduced for clinical use and has played a significant role in the development of heart valve replacement therapies.

Development and History

The development of the Hancock Aortic Tissue Valve marked a significant advancement in cardiac surgery. Prior to the introduction of bioprosthetic valves, patients requiring aortic valve replacement had the option of mechanical valves, which come with a lifelong requirement for anticoagulation therapy. The Hancock valve, developed by the Hancock Laboratories in the late 1960s, offered an alternative that, for some patients, eliminated the need for anticoagulation therapy.

Design and Material

The Hancock Aortic Tissue Valve is designed to mimic the function of a natural heart valve. It is constructed from porcine aortic valves, which are chemically treated with glutaraldehyde to cross-link the proteins and reduce immunogenicity, making the valve more acceptable to the human immune system. The valve is then mounted on a flexible stent to facilitate implantation and ensure proper function within the heart.

Surgical Procedure

The replacement of the aortic valve with a Hancock Aortic Tissue Valve requires open-heart surgery. The procedure involves the removal of the diseased valve and the implantation of the bioprosthetic valve in its place. The surgery is performed under general anesthesia and requires the use of a cardiopulmonary bypass machine to maintain blood circulation during the operation.

Advantages and Disadvantages

The Hancock Aortic Tissue Valve offers several advantages over mechanical valves, including a reduced need for anticoagulation therapy, which lowers the risk of bleeding complications. Additionally, many patients prefer bioprosthetic valves for their more natural sound and feel. However, bioprosthetic valves, including the Hancock valve, tend to have a shorter lifespan than mechanical valves, often requiring replacement after 10 to 15 years due to structural valve deterioration.

Clinical Outcomes

Clinical studies have shown that the Hancock Aortic Tissue Valve provides good short- to medium-term outcomes for patients undergoing aortic valve replacement. The risk of thromboembolism is significantly lower compared to mechanical valves, but there is an increased risk of valve degeneration over time. Patient selection is crucial to optimize outcomes, with younger patients often advised to consider mechanical valves due to their longer lifespan.

Conclusion

The Hancock Aortic Tissue Valve represents a significant advancement in the field of cardiac surgery, offering patients an alternative to mechanical heart valves. While it has its limitations, particularly in terms of durability, its development has paved the way for further innovations in bioprosthetic valve technology.