Aortic Stenosis

The function of the heart is to pump blood throughout our circulatory system, supplying oxygen and nutrients to our tissues and removing carbon dioxide and other waste products. To facilitate this process the heart has four chambers and four valves that control the flow of blood in and out of the heart. The heart valves stop blood from flowing back into the heart after it has been pumped out.

One of the four valves is called the aortic valve, which is situated at the top of the left ventricle and leads to the aorta (the major blood vessel that circulates oxygenated blood around your body). If aortic stenosis occurs, this means that the aortic valve cannot open fully, which leads to a restriction in blood flow and forces the heart to work harder to pump blood through.

What causes aortic stenosis?

There are three major causes of aortic stenosis:

• Congenital heart defect. The aortic valve consists of three tightly fitting, triangular-shaped flaps of tissue called cusps. Some children are born with an aortic valve that only has two cusps instead of three. On rare occasions, some people may be born with only one or up to four cusps. This may not cause problems until adulthood, at which time the valve may begin to narrow or leak and may need to be repaired or replaced.
• Calcium build-up on the valve. With age, heart valves may accumulate deposits of calcium which is a mineral found in your blood. As blood repeatedly flows over the aortic valve, deposits of calcium can build up on the valve’s cusps. These calcium deposits may never cause problems but in some people, they may result in stiffening the cusps of the aortic valve. This stiffening narrows the aortic valve which obstructs blood flow and forces the heart to work harder.
• Rheumatic fever. A complication of strep throat infection, rheumatic fever may result in scar tissue forming on the aortic valve which can lead to aortic stenosis. Scar tissue can also create a rough surface on which calcium deposits can collect, contributing to aortic stenosis later in life.

Signs and symptoms

Aortic stenosis ranges from mild to severe and symptoms generally develop when the narrowing of the valve is severe. Some people with aortic stenosis may not experience symptoms for many years. Signs and symptoms of aortic stenosis may include:

• Chest pain or tightness (angina)
• Feeling faint or fainting upon exertion
• Shortness of breath upon exertion
• Fatigue upon exertion
• Heart palpitations (sensations or a rapid, fluttering heart)

Diagnosis and treatment

Diagnosing aortic stenosis early is key to successful treatment. Unless treated, aortic stenosis can lead to major complications including heart failure, stroke, blood clots, bleeding, arrhythmias (heart rhythm abnormalities), infections that affect the heart and death.

Your consultant may carry out tests including auscultation (listening to your heart with a stethoscope) and echocardiogram (to assess the condition of the aortic valve and the way blood flows through your heart) to determine the type of treatment required.

There are two treatment options for aortic stenosis. Primarily, surgical aortic valve replacement (SAVR) which is an open-heart procedure where the surgeon removes the narrowed valve and replaces it. Alternatively, there is a less invasive procedure called transcatheter aortic valve implantation (TAVI). This enables replacement of the aortic valve without opening the chest.