The most common causes of heart valve disease are degenerative congenital defects and infections. However, age-related changes and certain autoimmune diseases, such as lupus, Graves' disease, and Hashimoto's thyroiditis, have also been associated with heart valve disease.
Congenital Defects and Heart Valve Disease
Congenital defects are most often associated with aortic or pulmonary valve disease. In patients with congenital defects, the heart valves may be the wrong size or the leaflets of the valve are misshapen or not properly attached. In bicuspid aortic valve disease, the valve has only two leaflets instead of the normal three.
Types of congenital defects associated with heart valve disease include:
Pulmonary valve stenosis - a narrowing of the pulmonary valve that restricts blood flow from the right ventricle into the pulmonary artery. This can range from mild to severe and, with the exception of a heart murmur, is often asymptomatic.
Bicuspid aortic valve disease - a congenital disease that causes the aortic valve to have only two leaflets instead of three seen in the tricuspid. This causes the valve to be stiff or to leak.
Marfan syndrome - a genetic connective tissue disorder that affects the body's main arteries and may cause the aorta to stretch and grow weak. This condition is called aortic dilation or aortic aneurysm and may require the repair or replacement of the aortic heart valve.
Infections and Heart Valve Disease
Two types of infections are commonly associated with heart valve disease, rheumatic fever and infective endocarditis. In these cases, heart valve disease occurs when the infection travels to the heart and damages the inner surface, which includes the heart valves.
Rheumatic fever is caused by an untreated streptococcus pyogenes infection, such as strep throat. When the body tries to fight the strep infection it can damage or scar the heart valves, typically the aortic or mitral valves. Symptoms of heart valve damage often don't appear for many years. Heart valve disease due to rheumatic fever mainly affects older people who had strep infections before antibiotics were available as well as people from developing countries.
Infective endocarditis is usually the result of bacteria - such as staphylococcus aureus and enterococcus - or other infectious substances that enter the bloodstream intravenously or through breaks in the skin and gums and infect the inner surface of the heart. This rare and sometimes life-threatening infection can damage the heart and worsen the condition of individuals with preexisting heart conditions.
Other Conditions
Heart valve disease can also be caused by age-related disorders, such as an increase in calcium or other deposits in the heart, or other conditions and risk factors.
Conditions and risk factors sometimes related to heart valve disease include:
Carcinoid syndrome, which occurs when a carcinoid tumor secretes chemicals into the bloodstream
Uncommon metabolic disorder, such as Fabry disease and hyperlipidemia
The combined use of fenfluramine and phentermine ("Fen-Phen"), a prescription weight-loss supplement in frequent use between 1995 and 1997
Radiation therapy to the chest area, typically in the treatment of cancer