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| Objectives |
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At the completion of this chapter, the student will be able to:
- Understand normal and abnormal aortic valve anatomy
- Obtain TEE views to evaluate the aortic valve, LVOT and aortic root
- Evaluate the severity of aortic stenosis and regurgitation
- Discuss the etiology and progression of aortic stenosis and regurgitation
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| Introduction |
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Echocardiographic evaluation of the aortic valve involves the identification of the aortic valve anatomy, function, hemodynamics and secondary or associative conditions with aortic valve pathology. The qualitative and quantitative assessment of the aortic valve can indicate the severity of the disease process, the success of an aortic valve repair, the prediction of the performance of a valve replacement, and the diagnosis of complications from aortic valve repair or replacement. Transesophageal echocardiography has been shown to alter the Intraoperative plan in up to 13% of patients undergoing aortic valve repair. Assessment of associative conditions such as diastolic dysfunction or decreased compliance help with the fluid and inotropic therapy during the perioperative period. The diagnosis of occult aortic valve disease can reduce perioperative morbidity and mortality or for the need for reoperation.
This chapter discusses normal anatomy, basic techniques for grading of aortic stenosis and aortic regurgitation by jet size and pressure gradient. Advanced topics like aortic valve area by continuity equation and PISA and the surgical implications are discussed in detail in the Advanced Section of E-echocardiography.com. |
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| Normal Aortic Valve Anatomy |
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| The aortic valve is a key orienting structure for the echocardiographer during an intraoperative transesophageal echocardiography exam. Its distinctive 3 leaflet, inverted "Y" or Mercedes-Benz logo type structure provides a marker through which other cardiac structures can be determined. The aortic valve is the "roof" of the left ventricular outflow tract and is in continuity with the anterior mitral leaflet. Upon identifying the aortic valve, the examiner can easily identify the nearby perivalvular structures, especially in a patient with altered anatomy where standard views are not obtainable. |
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| Aortic Valve Cusps |
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| The aortic valve consists of three leaflets or cusps. Each cusp opens into a nearby out pouching called the Sinus of Valsalva. The sinuses of valsalva and the coronary cusps are named by the associated coronary artery ostia. The most anterior cusp, associated with the right coronary artery ostia, is called the right coronary cusp (RCC). The left cusp, which is associated with the left main coronary artery, is called the left coronary cusp (LCC). The remaining right posterior cusp, not associated with a coronary artery, is called the non-coronary cusp (NCC). The non-coronary cusp is associated with the interatrial septum. The tips of each cusp are slightly thickened and the contact point can be thickened and/or calcified. The contact point contains a discreet node called the Node of Arantii. The nodes of Arantii can be confused with pathology when examined echocardiographically. The cusps, during systole, extend into the sinus of valsalva but do not contact the sinus walls or the coronary ostia. The aortic valve cusps are suspended by a fibrous ring, the aortic annulus. |
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| Since the aortic valve is a trileaflet valve, the leaflets can fully open during blood ejection. A bileaflet valve cannot fully open during blood ejection. A bileaflet aortic valve will not be as efficient as a trileaflet aortic valve, and, therefore, will tend to fail earlier in life than a trileaflet valve. Quadricuspid aortic valves also exist. Quadricuspid valves are 4 equal sized leaflet aortic valves. Interestingly, quadricuspid valves tend to be associated with aortic regurgitation. |
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| Bileaflet Aortic Valve |
Quadricuspid Aortic Valve |
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| Aortic Valve Views |
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| Because the aortic valve lies close to the esophagus, high quality scans of the aortic valve are possible. The aortic valve lies in an oblique plane from the esophageal plane so longitudinal plane rotation is required to view the valve's long or short axis. The ASC/SCA standard views of the aortic valve are the midesophageal aortic valve short axis (ME AVSAX), the midesophageal aortic valve long axis (ME AVLAX), the transgastric aortic valve long axis (TG AVLAX), and the deep transgastric aortic valve long axis (DT AVLAX). These views allow for the 2D, Color Doppler, M Mode, Pulse Doppler, and Continuous Doppler interrogation of the aortic valve. |
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