tailieunhanh - Ebook ASE's Comprehensive echocardiography textbook (2nd edition): Part 2

(BQ) Part 2 book "ASE's Comprehensive echocardiography textbook" presents the following contents: Aortic stenosis, aortic regurgitation, mitral stenosis, pulmonic regurgitation, prosthetic valves, mitral regurgitation, infective endocarditis, pericardial diseases,. | Section XV Aortic Stenosis 94 Aortic Stenosis Morphology Steven A. Goldstein MD CONGENITAL AORTIC STENOSIS Bicuspid Aortic Valve Congenital aortic valve malformation reflects a phenotypic continuum of unicuspid valve severe form bicuspid valve moderate form tricuspid valve normal but may be abnormal and the rare quadricuspid forms. Bicuspid aortic valves BAVs are the result of abnormal cusp formation during the complex developmental process. In most cases adjacent cusps fail to separate resulting in one larger conjoined cusp and a smaller one. Therefore BAV or bicommissural aortic valve has partial or complete fusion of two of the aortic valve leaflets with or without a central raphe resulting in partial or complete absence of a functional commissure between the fused The generally accepted prevalence of BAV in the general population is 1 to 2 making it the most common congenital heart defect. Information on the prevalence of BAV comes primarily from pathology Valvular aortic stenosis AS a chronic progressive disease usually develops over decades. Box lists the most common etiologies of valvular AS as illustrated in Figure . The majority of cases of AS are acquired and result from degenerative calcific changes in an anatomically normal trileaflet aortic valve that becomes gradually dysfunctional over time. Congenitally abnormal valves may be stenotic at birth but usually become dysfunctional during early adolescence or early adulthood. A congenitally bicuspid aortic valve is now the most common course of valvular AS in patients under the age of 65. Rheumatic AS is now much less common than in prior decades and is virtually always accompanied by mitral valve disease. Other forms of nonvalvular left ventricular outflow obstruction . discrete subvalve AS hypertrophic cardiomyopathy and supravalve AS are discussed in other chapters. The most reliable estimate of BAV prevalence is often considered to be the reported by Larson and