Our heart has four valves: tricuspid, mitral, aortic and pulmonary. These valves act like one-way doors to help the blood flow in one direction. When one (or more) of these valves become narrow and stiff, it does not open completely, and blood cannot flow freely through it. Blood leaks back to the previous chamber, and the heart cannot push the enough blood forward to the next chamber to maintain blood flow. Together, these problems lower the ability of the heart to pump blood efficiently and can lead to heart valve disease. Heart valve disease affects approximately 2.5% of adults in the U. S. and millions of people worldwide.
What is heart valve disease?
Heart valve disease can develop for several reasons, including aging, inflammation of the heart’s lining (called endocarditis), autoimmune diseases, conditions we’re born with and other types of heart disease. The symptoms of heart valve disease may appear quickly or can progress slowly over time and can include irregular beating of the heart, shortness of breath, chest pain, dizziness or fainting.
How is heart valve disease treated?
Medications can help manage heart valve disease. But when it progresses to a severe stage, treatment options often become limited, and a surgeon may need to repair or replace the diseased valve.
Heart valve replacement
Depending on the age of the person and how advanced their heart valve disease is, a replacement valve could be either mechanical or bioprosthetic. Bioprosthetic heart valves are generally made from the tissue surrounding the heart of a cow (bovine)or aortic valves of a pig (porcine). These tissues are rich in collagen—a connective tissue that provides structure—and unlike mechanical valves, people who have bioprosthetic valves don’t need to take anticoagulant or blood thinner medications for the rest of their lives. However, bioprosthetic valves are under constant mechanical stress while opening and closing. Blood clots and calcium deposits can form in and around them over time. They can also become inflamed and wear out.
Creating a better valve
Scientists can use different compounds or chemicals to change the surface of the biomaterials that replacement valves are made of. This can change its chemical and biological properties, helping it interact more effectively with the body. Although many compounds have been investigated for this purpose, researchers have not been able to find a specific compound that can fully overcome the limitations of bioprosthetic valves.
My current research focuses on evaluating different compounds and using them to modify the surface of the bovine tissues. My goal is to find a specific compound and find the best conditions for making it compatible with blood, helping endothelial cells attach, and reducing inflammation and calcification. Ultimately, this could help make bioprosthetic heart valves last longer. This research may help identify new ways to develop heart valves that work well with the body while resisting the processes that can cause them to fail.
Sachin Aryal, PhD, is a T32 Postdoctoral Fellow at the Abramson Research Center at the Children’s Hospital of Philadelphia. His research focuses on developing strategies to enhance the hemocompatibility and biocompatibility of bovine pericardium for use in bioprosthetic heart valve applications.