Valvular heart disease: Causes and risk factors

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Valvular heart disease is any cardiovascular disease process involving one or more of the four valves of the heart (the aortic and mitral valves on the left side of heart and the pulmonic and tricuspid valves on the right side of heart). These conditions occur largely as a consequence of ageing, but may also be the result of congenital (inborn) abnormalities or specific disease or physiologic processes including rheumatic heart disease and pregnancy. Anatomically, the valves are part of the dense connective tissue of the heart known as the cardiac skeleton and are responsible for the regulation of blood flow through the heart and great vessels. Valve failure or dysfunction can result in diminished heart functionality, though the particular consequences are dependent on the type and severity of valvular disease. Treatment of damaged valves may involve medication alone, but often involves surgical valve repair or replacement (insertion of an artificial heart valve).

Causes and risk factors

Calcific disease

Calcification of the leaflets of the aortic valve is a common with increasing age, but the mechanism is likely to be more related to increased lipoprotein deposits and inflammation than the "wear and tear" of advance age. Aortic stenosis due to calcification of tricuspid aortic valve with age comprises >50% of the disease. Aortic stenosis due to calcification of a bicuspid aortic valve comprises about 30-40% of the disease. Hypertension, diabetes mellitus, hypolipoproteinaemia and uraemia may speed up the process of valvular calcification.

Dysplasia

Heart valve dysplasia is an error in the development of any of the heart valves, and a common cause of congenital heart defects in humans as well as animals; tetralogy of Fallot is a congenital heart defect with four abnormalities, one of which is stenosis of the pulmonary valve. Epstein’s anomaly is an abnormality of the tricuspid valve, and its presence can lead to tricuspid valve regurgitation.  A bicuspid aortic valve is an aortic valve with only 2 cusps as opposed to the normal 3. It is present in about 0.5% to 2% of the general population, and causes increased calcification due to higher turbulent flow through the valve.

Connective tissue disorders

Marfan's Syndrome is a connective tissue disorder that can lead to chronic aortic or mitral regurgitation. Osteogenesis imperfecta is a disorder in formation of type I collagen and can also lead to chronic aortic regurgitation.

Inflammatory disorders

Inflammation of the heart valves due to any cause is called valvular endocarditis; this is usually due to bacterial infection but may also be due to cancer (marantic endocarditis), certain autoimmune conditions (Libman-Sacks endocarditis, seen in systemic lupus erythematosus) and hypereosinophilic syndrome (Loeffler endocarditis). Endocarditis of the valves can lead to regurgitation through that valve, which is seen in the tricuspid, mitral, and aortic valves. Certain medications have been associated with valvular heart disease, most prominently ergotamine derivatives pergolide and cabergoline.

Heart disease

Tricuspid regurgitation is usually secondary to right ventricular dilation which may be due to left ventricular failure (the most common cause), right ventricular infarction, and inferior myocardial infarction. Other causes of tricuspid regurgitation include carcinoid syndrome and myxomatous degeneration.

Media Contact:

John Mathews

Journal Manager

Current Trends in Cardiology

Email: cardiologyres@eclinicalsci.com