Jonathan Chen, MD: A mechanical valve can be used to replace a damaged or diseased aortic or mitral valve. I'm Jonathan Chen, a surgeon in the Pediatric Heart Valve Center at Children's Hospital of Philadelphia. My team is one of the most experienced in the country in valve repair and replacement. To better understand mechanical valve replacement, let's first take a look at the anatomy of the heart. This is your heart. It has four chambers and four valves.

The upper chambers are the left atrium and the right atrium. The lower chambers are the left ventricle and the right ventricle. Before entering or leaving each chamber of the heart, blood passes through a valve. The mitral valve is between the chambers on the left side of the heart. The left atrium receives oxygen-rich blood from the lungs and pumps it through the mitral valve to the left ventricle.

The left ventricle then pumps the blood through the aortic valve and into the aorta, the largest artery in the body. Blood travels from the aorta to blood vessels throughout the body, delivering oxygen and nutrients. Heart valves are made of flaps of tissue called leaflets. The leaflets work like one way doors, opening to let blood move forward, and closing to keep blood from flowing backward. Watch how the leaflets move from another angle, opening to let blood move forward and closing to keep blood from flowing backward.

The leaflets are attached to a strong tissue called the annulus. The annulus helps maintain the shape of the valve. If a valve is diseased or damaged, it can be surgically removed and replaced with a mechanical valve. A mechanical valve is made of metal and plastic. A thick cloth surrounds the valve. Just like your child's heart valves, the leaflets in the mechanical valve open and close to keep blood flowing through your heart. The mechanical leaflets make a soft clicking noise as they open and close. You can hear it, if you have a mechanical valve. Patients adjust to the sound and are eventually able to ignore it. You might have heard of adults who have bioprosthetic valves, made of tissue from pigs or cows.

These valves have a high risk of becoming hard over time, in a process called calcification, causing these valves to last less than three to five years in children. During a mechanical valve replacement, your surgeon will remove the diseased or damaged valve and choose the right size replacement valve for your child.

The surgeon will suture the mechanical valve to the annulus using the sewing ring or cloth rim of the valve. At the Valve Center at Children's Hospital of Philadelphia, our team uses cutting edge imaging to view each patient's heart before surgery. This allows us to develop a highly personalized surgical plan based on your child's unique anatomy.

In babies and toddlers, a mechanical valve will need to be upsized as your child grows. While a teenager may only need one valve operation, a baby or toddler will likely need two or three re-operations over time. A mechanical valve has an increased risk of infection. It's important to tell your doctor if your child has a serious cut or lesion because they may need antibiotics to prevent infection from traveling to the heart.

It is possible for scar tissue, called pannus, to grow around the mechanical valve. Too much scar tissue can make it hard for the leaflets to move, requiring a replacement valve. Patients with mechanical valves must take daily blood thinners to prevent clotting on the valve. If a blood clot detaches from the valve and travels to another area of the body, this can be life-threatening. Blood thinning medication needs careful management.

Dosage must be monitored regularly, which can be done at home. When your child is facing heart valve surgery, we know there are difficult decisions to make. Our experts work together and with you, to make the best decisions for your child before, during, and after surgery.