Edmund A. Bermudez, MD, MPH
Two-Dimensional Assessment Doppler Assessment Calculation of Aortic Valve Area Assessment of Stenosis Severity Low-Gradient Aortic Stenosis Pitfalls Conclusion Suggested Reading introduction
Transthoracic echocardiography has largely replaced cardiac catheterization as the primary modality for the hemodynamic assessment of valvular heart disease. A comprehensive evaluation of valve structure, function, and hemodynamics is possible through a carefully performed transthoracic study. In the case of aortic stenosis, echocardiography is used to define the initial severity of disease, etiology, and monitor its progression through serial follow up studies. Evaluation of aortic stenosis would be incomplete without a comprehensive examination of overall left ventricular function and estimation of pulmonary artery pressures. Transthoracic echocardio-graphy, therefore, can provide important information about the initial diagnosis, management, and follow-up of adult patients with native aortic valve stenosis.
When considering the etiology of aortic stenosis, it is important to consider the age and the demographics of the patient (Fig. 1). Rheumatic valvular disease, once the most common form of aortic stenosis, is less common today in developed countries. Commissural fusion is a hallmark of this disease and often presents with concomitant mitral stenosis (Fig. 2; please see companion DVD for corresponding video). Less commonly, the commissures may fuse eccentrically, producing a de facto bicuspid valve. In this case, differentiation from a congenitally bicuspid valve can be difficult.
Calcific degeneration is currently the most common form of aortic stenosis in the developed world. It generally presents later in adult life and is sometimes called senile calcific degeneration (Fig. 3). Commissural fusion can occur, but is not a hallmark of this disease process. Calcification is visualized as "echo bright" reflectivity of the valve leaflets and the aortic root.
Congenital bicuspid aortic valves may calcify and thicken over time, eventually producing stenotic lesions that present earlier than other common causes of adult aortic valvular stenosis (Fig. 1). When observed in the parasternal short-axis view, bicuspid aortic valves exhibit either a vertical or a horizontal commissural orientation in the parasternal short-axis view. In the vertical orientation, commissures are in the anterior and posterior position with a right and left cusp. In the horizontal orientation, commissures are in the right and left positions, with anterior and posterior cusps. Raphes are commonly seen in both of these orientations (Fig. 4).
From: Contemporary Cardiology: Essential Echocardiography: A Practical Handbook With DVD Edited by: S. D. Solomon © Humana Press, Totowa, NJ
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