Pediatric Aortic Valve Insufficiency Workup

Several imaging studies can be performed to diagnose and assess the severity and impact of aortic valve insufficiency, including plain-film radiography, angiographic studies, echocardiography, radionuclide imaging, and nuclear MRI imaging. Cardiac MRI has become the imaging study of choice for the evaluation of aortic insufficiency in children.

• Plain-film radiography

  • Perform plain-film radiographic studies to evaluate the duration and severity of insufficiency and to look for a possible etiology.

    • Evaluate cardiac size to assess the duration and severity of aortic valve insufficiency.

    • Evaluate left ventricular (LV) function.

    • Assess increases in the long axis and transverse diameter of the heart.

    • Assess possible aortic valve calcification.

    • Assess the size of aortic root.

    • Look for aneurysms.

    • Look for linear calcifications.

  • Radiographic findings may provide clues to the possible etiology.

    • Cardiac enlargement can indicate chronicity of aortic valve insufficiency.

    • LV enlargement in the long axis with displacement of the point of maximal impulse laterally and inferiorly can occur with chronic aortic valve insufficiency.

    • Aortic valve calcification can occur with combined aortic and mitral regurgitation, but this is not likely in patients with pure aortic valve insufficiency.

    • Left atrial enlargement despite good left heart function can suggest a mitral insufficiency instead of aortic valve insufficiency.

    • Dilation of the aortic root and ascending aorta can indicate disease of the aortic root (eg, cystic medial necrosis, Marfan syndrome, aortic annular ectasia).

    • Linear calcifications in the ascending aorta suggest disease of the ascending aorta (eg, syphilis).

• Angiographic studies

  • Results may provide clues for differentiating acute aortic valve insufficiency from chronic aortic valve insufficiency.

  • Look for LV end-diastolic volume.

  • Look for thickness of LV wall.

  • In acute aortic valve insufficiency, no significant increase in LV end-diastolic volume occurs initially, but, eventually, the LV wall thickens and the end-diastolic LV volume increases.

• Echocardiography

  • Look for the etiology of aortic valve insufficiency and assess the need for surgical intervention.

  • Look for the following:

    • Thickening of the valve cusps

    • Morphology of the commissures, presence of a raphe

    • Cusp prolapse

    • Detached or flailing valve cusps

    • Vegetations

    • Aortic root dilatation

    • LV wall thickness

    • LV end-diastolic dimension

    • LV end-systolic dimension

    • LV shortening fraction

    • LV end-systolic wall stress–velocity of circumferential fiber shortening (Vcfc) relationship

  • Echocardiographic findings specific to acute severe aortic valve insufficiency include the following:

    • The mitral valve opens late and closes early.

    • The LV functions at the steep portion of the pressure-volume curve.

    • LV end-diastolic volume is only slightly increased.

    • The shortening fraction is normal to low.

  • Echocardiographic findings specific to chronic severe aortic valve insufficiency include the following ^[3] :

    • The mitral valve opens early and closes late.

    • The LV functions at the flattened portion of the pressure-volume curve.

    • LV end-diastolic volume and pressure are increased.

    • Left heart wall motion is increased.

    • Aortic valve opens early when aortic and LV pressures equalize.

  • Echocardiographic findings in acute and chronic aortic valve insufficiency include diastolic high-frequency fluttering of the anterior leaflet of the mitral valve in aortic valve insufficiency.

    • Suggestive of aortic regurgitation (AR) and caused by regurgitant flow

    • Not observed when mitral valve is rigid

    • Can occur in mild and severe aortic valve insufficiency

  • Doppler echocardiography with color flow is one of the most accurate and sensitive noninvasive imaging studies in aortic valve insufficiency.

    • Measures the velocity of regurgitant jet and can therefore be informative about the difference between the aortic and ventricular diastolic pressures

    • Measures the rate of decrease in the velocity of regurgitant jet in the LV

    • Measures the size of defect in the aorta, through which the regurgitant flow passes

    • Can compare the velocity of regurgitant flow in the aortic, mitral, and pulmonic valves

• Radionuclide imaging: This modality is very expensive but is an accurate noninvasive evaluation of aortic valve insufficiency. It can be useful and assist with the following:

  • Determination of fraction of regurgitation

  • Ratio of LV–to–right ventricular stroke volume

  • Differential diagnosis of mitral, pulmonic, or tricuspid regurgitation

  • Serial studies to help identify evolving LV failure

  • Measurement of regurgitant volume

  • Measurement of end-systolic and end-diastolic volume of LV

• Cardiac MRI

  • Cardiac MRI has become an important modality in the evaluation of aortic insufficiency in children. Recent advances such as faster scanning techniques, higher spatial resolution, avoidance of ionizing radiation, lack of reliance on contrast material, and the ability to obtain functional imaging have made it an emerging noninvasive diagnostic tool with great potential in children.

  • The ability to obtain clear images that reveal the anatomy and structure of the aortic valve, allowing for evaluation of valve competence, is beneficial.

  • Evaluation of the ventricular structure and function is indicated to assess the degree of functional impairment of the LV as a result of aortic insufficiency.

  • Differential diagnosis of mitral, pulmonary, or tricuspid regurgitation can be assessed.

  • Serial studies help identify evolving LV failure.

  • Evaluation of shunting and shunt physiology is possible.

  • Cardiac MRI can be used as a primary tool or in conjunction with echocardiography to provide additional information on structures that are difficult to evaluate using an echocardiographic method (eg, the right heart).

See the list below:

• Electrocardiography in acute aortic valve insufficiency

  • Prolongation of the PR interval

  • Nonspecific T-wave changes

  • Nonspecific ST-segment changes

  • Possible left axis deviation caused by left heart failure

  • No left axis deviation despite left heart failure (Depending on the duration and severity of insufficiency, LV hypertrophy may result in left axis deviation.)

• Electrocardiography in chronic aortic valve insufficiency

  • LV hypertrophy

  • LV volume overload

  • Increased end-diastolic volume in the LV

  • Progression to LV conduction defect with sufficient hypertrophy and volume overload

  • Eventual LV dysfunction

  • LV failure

• Initial presentation in chronic aortic valve insufficiency

  • Definite LV hypertrophy showing as left axis deviation

  • Prominent Q waves in lead I, aVL, and anterior leads

  • Small R wave in V₁ lead

  • Possible peak T waves in left precordial leads

• Progression of chronic aortic valve insufficiency

  • Increasing amplitude of QRS complex with continued LV hypertrophy

  • T waves become inverted

  • ST-segment depression

  • Possible PR interval increase (may suggest inflammatory process responsible for aortic valve insufficiency)

See the list below:

• Cardiac catheterization and angiography

  • Aid in decisions regarding surgical treatment

  • Accurate measurement of the magnitude of regurgitation and the status of LV function

  • Evaluation of the condition of the coronary arterial bed