Aortic stenosis (AS) in adults is a chronic, progressive disease that develops - usually over decades - due to calcification of a normal trileaflet or congenital bicuspid valve. The active disease process shares many similarities with atherosclerosis, including lipid accumulation, inflammation, and calcification. Once initiated, progressive leaflet calcification and fibrosis leads to reduced leaflet motion, a reduction in effective valve area, and obstruction of left ventricular (LV) outflow. Once the predominant form of the disease, rheumatic AS is much less common today and is invariably accompanied by mitral valve disease. A congenital malformation of the valve now is the more common cause of congenital-related AS in young adults. Although AS is best described as a disease continuum, there is no single value that defines severity. The new 2006 update of the American College of Cardiology/American Heart Association (ACC/AHA) Guidelines for the Management of Patients with Valvular Heart Disease grades AS severity on the basis of a variety of hemodynamic and natural history data (Slide 1) using definitions of aortic jet velocity mean pressure gradient, and valve area. The natural history of AS in the adult consists of a prolonged latent period during which morbidity and mortality are very low. Therapeutic decisions, particularly those related to corrective surgery, are based largely on the presence or absence of symptoms. Asymptomatic patients have a low risk of mortality, but this risk increases dramatically once symptoms appear. Even patients with severe AS have a much better event-free survival when they remain asymptomatic versus those with symptoms (Slide 2). Consequently, aortic valve replacement (AVR) is appropriate with even mild symptoms, regardless of the absolute valve area (or transvalvular pressure gradient). Angina, syncope, and heart failure are the classic symptoms of AS; however, most prospectively followed patients present with more subtle symptoms, such as decreased exercise tolerance or dyspnea on exertion. Adding to the clinical challenge is the number of patients who decrease their activity level below their symptom threshold - a careful history comparing current and last year's activity levels is needed to recognize that these patients, in fact, are symptomatic. A table and graph is presented. Because of marked individual variability in the rate of lesion and hemodynamic progression, it is not possible to predict the rate of progression in an individual patient. For this reason, regular clinical follow-up is mandatory in all patients with asymptomatic mild to moderate AS. Progression to AS may occur in patients with aortic sclerosis, defined as irregular valve thickening without obstruction to LV outflow. Aortic sclerosis is present in about 25% of adults more than 65 years of age and is associated with age, sex, hypertension, smoking, serum low-density lipoprotein, lipoprotein(a) levels, and diabetes mellitus. In the Cardiovascular Health Study, the presence of aortic sclerosis on echocardiography in subjects without known coronary disease was also associated with adverse clinical outcome, with an approximately 50% increased risk of myocardial infarction and cardiovascular death compared with subjects with a normal aortic valve.
|Original language||English (US)|
|Number of pages||6|
|Journal||ACC Cardiosource Review Journal|
|State||Published - Jul 1 2006|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine