Aortic Valve Anatomy

Aortic Valve OutlineAortic Valve Anatomy2D Views of the Aortic Valve2D Evaluation of the Aortic Valve - Part 12D Evaluation of the Aortic Valve - Part 22D Evaluation of the Aortic Valve - Part 33D Evalutation of the Aortic Valve2D and M Mode Evaluation of the Aortic ValveColor Doppler Evaluation of the Aortic Valve - Part 1Color Doppler Evaluation of the Aortic Valve - Part 2Doppler Evaluation of the Aortic Valve ApparatusCauses and Natural History of Aortic Stenosis2D/3D Aortic Stenosis EvaluationAortic Valve Area by Continuity EquationAortic Valve Area by PISAAVA by Gorlin and Aortic Valve GradientsAortic Valve Area by Velocity Ratio and Dobutamine InfusionSubaortic Stenosis EvaluationAortic Stenosis Coexisting DiseasesDetermination of Aortic Stenosis SeverityCardiovascular Response to Aortic Stenosis and the Timing of AVRAortic Regurgitation Causes and Natural History2D Evaluation of Aortic Regurgitation3D Evaluation of Aortic RegurgitationPulse Wave Doppler Evaluation of Aortic RegurgitationRegurgitant Volume/Fraction and Effective Regurgitant OrificeColor Doppler Evaluation of Aortic Regurgitation - Part 1Color Doppler Evaluation of Aortic Regurgitation - Part 2Aortic Regurgitation SeverityIndications for Aortic Valve ReplacementTranscatheter Aortic Valve ImplantationSummaryCME and Self Assessment Exams
Objectives

At the completion of this chapter, the student will be able to:
  1. Understand normal and abnormal aortic valve anatomy
  2. Obtain TEE views to evaluate the aortic valve, LVOT and aortic root
  3. Evaluate the severity of aortic stenosis and regurgitation
  4. Discuss the etiology and progression of aortic stenosis and regurgitation
Introduction

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.
Normal Aortic Valve Anatomy

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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Base of the Heart

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Aortic Valve Short Axis Systole
Aortic Valve Short Axis Diastole 		ME AVSAX 2D Zoom
Aortic Valve Cusps

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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Cusps Nodes of Arantii SOV/Annulus LAX Image Nodes of Arantii

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.

Bileaflet Aortic Valve Quadricuspid Aortic Valve
Aortic Root and Left Ventricular Outflow Tract

The aortic valve is a component of the aortic root . The aortic valve can be affected by, and in turn, affect the aortic root. The aortic root consists of the aortic valve (aortic valve cusps and aortic valve annulus), the Sinuses of Valsalva (SOV), the sinotubular junction (STJ)(junction of the sinus of valsalva and ascending aorta), and the ascending aorta. The aortic root's narrowest point is the aortic valve annulus, out pouches at the level of the sinuses of valsalva, narrows to the sinotubular junction and enlarges at the level of the ascending aorta . Proximal to the aortic valve is the left ventricular outflow tract (LVOT).


For the aortic valve to function normally, proper orientation and dimensions must be maintained. Normal orientation includes a ratio of LVOT:Sinus of Valsalva Height:Sinotubular Junction Width. Derangement of these ratio's gives an indication of the pathology causing aortic regurgitation.

Structure Size (range)(cm )
LVOT 2.0 (1.8-2.2 cm)
Aortic Valve Annulus (AVAn) 1.9 (1.4-2.6 cm)
Sinus of Valsalva (SOV) 2.8 (2.1-3.5 cm)
Sinotubular Junction (STJ) 2.4 (1.7-3.4 cm)
Ascending Aorta (Asc Aorta) 2.6 (2.1-3.4cm)


LVOT: AV : STJ Dimensions Mathew and Ayoub.