In clinical practice, diagnosis and treatment of valvular heart disease are challenging for several reasons. Individual practitioners have less experience with valve disease compared with more prevalent conditions such as coronary disease, heart failure, hypertension, and atrial fibrillation. Few controlled clinical trials in patients with valvular heart disease have been published, so guidelines are largely based on clinical experience and expert opinion. In addition, our understanding of the pathophysiological responses to valve dysfunction is incomplete, and our knowledge of the basic mechanisms of disease in the valve leaflets is rudimentary.
The prevalence of different types of valvular heart disease continues to change worldwide as prevention of rheumatic fever results in fewer cases of rheumatic heart disease while, at the same time, increased longevity results in more cases of age-related calcific valve disease. Valve disease now is classified more accurately as primary or secondary. Primary valve dysfunction is due to a congenital anatomic abnormality such as a bicuspid aortic valve or to a disease process that affects the valve leaflets such as calcific aortic stenosis or myxomatous mitral valve disease. In contrast, secondary valve dysfunction is characterized by relatively normal valve leaflets with dysfunction due to alterations in valve geometry, as in, for example, mitral regurgitation in patients with ischemic disease or a cardiomyopathy. Treatment of secondary valve dysfunction is directed at treatment of the underlying disease process, whereas treatment of primary valve dysfunction is largely limited to watchful waiting with optimization of the timing of surgical or percutaneous intervention.
Noninvasive approaches to diagnosis of valvular heart disease, however, have transformed our understanding of the natural history of these conditions with the recognition that dysfunction can progress rapidly in some patients and that adverse clinical outcomes occur over a relatively wide range of hemodynamic severity. In addition, studies on human valve tissue and experimental models offer the hope that medical approaches to prevention of disease progression in primary valve disease may be possible in the future.
Many excellent review articles are available addressing the pathophysiology and clinical management of the most common types of valvular heart disease, specifically calcific aortic valve stenosis and myxomatous mitral valve regurgitation. There also have been recent reviews on aortic regurgitation, rheumatic valve disease, the bicuspid aortic valve, and congenital valvular heart disease. However, many other issues relevant to clinical decision making in adults with valvular heart disease have received less attention.
The goal of the series Valvular Heart Disease is to review the clinical implications of the basic pathobiology of valve disease and to provide a comprehensive review of several difficult management problems. The first 2 articles will focus on mitral valve biology and the left ventricular response to mitral regurgitation. The next series of articles will discuss the clinical utility of cardiovascular magnetic resonance imaging for evaluation and quantification of valve disease, selection of the optimal prosthetic valve, and the timing and indications for surgical intervention in adults with infective endocarditis. The clinical impact and management of right-sided valve disease also will be discussed. Finally, the importance of recognition, prompt treatment, and optimization of the surgical approach in adults with acute valvular regurgitation will be reviewed. The hope is that this series of articles will both stimulate further research in these areas and provide a concise and up-to-date review for the clinician.