Valvular heart disease: the influence of changing etiology on nosology

The many changes in classification of cardiovascular disease during the twentieth century reflect changing etiology of diseases, clinical comprehension and technological advances. In particular, the etiology of valvular heart disease has changed dramatically in the last five decades. The significant reduction of acute rheumatic fever and its sequelae, and the recognition of non-rheumatic causes of valvular disease are responsible for the metamorphosis in the etiology of valvular disorders. Valvular heart disease can be classified as follows: 1) Heritable-congenital causes of valvular heart disease e.g., floppy mitral valve with mitral valve prolapse, bicuspid aortic valve, and the Marfan syndrome; 2) Inflammatory-immunologic causes such as rheumatic fever, acquired immune deficiency syndrome, endocardial proliferative disorders, and antiphospolipid syndrome; 3) Myocardial dysfunction-ischemic cardiomyopathy, dilated or hypertrophic cardiomyopathy-resulting in valvular heart disease; 4) Diseases and disorders of other organs as causes of valvular heart disease, e.g., chronic renal failure and carcinoid heart disease; 5) Valvular heart disease related to aging: calcific aortic stenosis and mitral annular calcification; 6) Valvular disease following interventions such as valvuloplasty, valve reconstructive surgery and valve replacement; and 7) Valvular disease related to drugs and physical agents, such as chronic ergotamine use, radiation therapy and trauma. In clinical practice the most common causes of mitral regurgitation are floppy mitral valve with mitral valve prolapse, ischemic heart disease, dilated cardiomyopathy and mitral annular calcification, while the most common cause of mitral stenosis is rheumatic fever. The most common causes of isolated aortic regurgitation are bicuspid aortic valve and floppy aortic valve, while the most common causes of isolated aortic stenosis are related to the bicuspid aortic valve and the development of calcific senile aortic stenosis. The most common causes of tricuspid regurgitation are dilated cardiomyopathy, ischemic cardiomyopathy, floppy tricuspid valve with tricuspid valve prolapse and infectious endocarditis. Combined mitral and tricuspid regurgitation occur with heritable connective tissue disorders, dilated or ischemic cardiomyopathy, while the most common cause of mitral stenosis plus aortic regurgitation is rheumatic fever. Statistics obtained from cardiac surgery and necropsy may underestimate the true incidence of certain valvular diseases by selection bias. This is particularly so with valvular disease associated with significant ventricular dysfunction, or in the elderly who may not be surgical candidates, or in cases where the valvular disease is not severe enough to require surgical intervention. Recent advances in hemodynamic and imaging technology allow clinicians to define valvular structure and function and to accurately classify valvular heart disease in clinical practice.