Pulmonic Stenosis Workup
- Author: Xiushui (Mike) Ren, MD; Chief Editor: Richard A Lange, MD, MBA more...
Plain Chest Radiography
A characteristic radiographic finding, even with mild valvular pulmonic stenosis (PS), is prominence of the main, right, or left pulmonary arteries caused by poststenotic dilatation.
The intrapulmonary vasculature usually appears normal, even in severe PS.
In critical PS, the pulmonary vasculature may appear decreased if significant right-to-left shunting occurs through a patent foramen ovale or atrial septal defect or if severe unilateral pulmonary artery branch obstruction is present.
The overall heart size usually is normal unless RV failure or tricuspid regurgitation develops.
A prominent right heart border suggesting right atrial enlargement may be present in as many as 50% of affected individuals.
Echocardiography provides a definitive confirmation of the diagnosis of PS. Both 2-dimensional and Doppler techniques should be used to comprehensively evaluate the pulmonic valve.
Using 2-dimensional imaging, thickening of the valves, characteristic doming of nondysplastic valves, and right ventricular (RV) hypertrophy can be noted readily (see image below). RV size and systolic function, right atrial (RA) size, and pulmonary artery dimensions can be quantified in most patients.
Color Doppler aids in both defining high velocity jets and localizing their origin. Pulsed waved Doppler (placed just proximal to the site of obstruction) and continuous wave Doppler are used to measure jet velocity, which can be converted to pressure gradient using the modified Bernoulli equation. Normally, no systolic gradient is present across the pulmonic valve. With PS, however, the RV systolic pressure increases and a pressure gradient occurs between the RV and pulmonary artery. Doppler studies of the stenotic valve can determine the severity of the gradient (see image below).
The pulmonary valve area of a healthy adult is 2.0 cm2/m2 of body surface area. Mild valvular PS is defined by a valve area larger than 1 cm2 and a transvalvular pressure gradient of less than 50 mm Hg. Moderately severe PS occurs if the valve area is 0.5-1.0 cm2, with a transvalvular pressure gradient between 50 and 75 mm Hg. Severe PS is defined by a valve area smaller than 0.5 cm2 and a transvalvular pressure gradient greater than 75 mm Hg.
RV hypertrophy with asymmetric septal hypertrophy may be present. In addition, restrictive physiology can be demonstrated by Doppler interrogations of tricuspid inflow, hepatic vein flow, and Doppler tissue imaging. A restrictive RV pattern is associated with worse RV systolic function and worse exercise tolerance.
Doppler evidence of right-sided pressures approaching or exceeding systemic pressures or a 2-dimensional echocardiogram demonstrating paradoxical septal motion during systole with reversal of the usual right convex curvature of the interventricular septum is an indication for therapeutic intervention (see image and video below).
Cardiac Catheterization and Pulmonary Angiography
Cardiac catheterization generally is not needed to verify the findings of noninvasive tests, except when a significant discrepancy is noted between clinical findings and echocardiographic findings. When performed, cardiac catheterization can diagnose PS by a pressure gradient from the pulmonary artery to the RV on "pull-back" of the pulmonary artery catheter. Cardiac catheterization may be useful in assessing the presence of concomitant congenital abnormalities.
In the case of isolated PPS, pulmonary angiography may be needed to establish the diagnosis.
The degree of (right) ventricular hypertrophy on the ECG is largely correlated directly with the severity of PS.
With mild PS, 50% of patients have a normal ECG tracing or only mild right-axis deviation.
With moderately severe PS, right-axis deviation and increased R-wave amplitude in V1 are seen.
Severe PS is associated with extreme right-axis deviation, a dominant R wave in AVR, and a prominent R wave (>20 mm) in V1.
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