Persistent Pulmonary Hypertension of the Newborn (PPHN)
Echocardiographic Images

 

Reviewed by Carl Kuschel and Jon Skinner
April
2002
Clinical Guidelines Back Newborn Services Home Page
Tricuspid Regurgitation Ductal Flow TVP/RVET and RPEP/RVET Atrial Shunting
Other Shunts Cardiac Function and Output References

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Estimation of Pulmonary Artery Pressure (PAP) is an important aspect of the diagnosis and treatment of Persistent Pulmonary Hypertension of the Newborn (PPHN).  There are a number of echocardiographic indicators which help to directly or indirectly measure PAP.

Tricuspid Regurgitation

RV pressure = RA pressure + (4 x (TR jet velocity)2).

Click on the thumbnail images to see a larger image
PPHN - 4 Chamber BW.jpg (175473 bytes)
  • The image to the left demonstrates an apical 4-chamber view of the heart.
  • The chambers and valves are labelled (LA Left Atrium, MV Mitral Valve, LV Left Ventricle, IVS Interventricular septum, RA Right Atrium, TV Tricuspid Valve, RV Right Ventricle).  The green wedge shape is the outline of the colour Doppler field seen in the next image.
PPHN - TR colour.jpg (177198 bytes)
  • In this image, colour Doppler has been applied.
  • The TR jet is seen as the blue-yellow streak heading upwards away from the tricuspid valve.
PPHN - TR Doppler.jpg (294909 bytes)
  • In this image, Doppler interrogation has been applied to determine the velocity of the TR jet.
    • The velocity is in the region of 2.9 m/sec, giving a gradient across the tricuspid valve of 34mmHg.  This indicates that that PAP is at least 34mmHg above RA pressure.  The RA pressure is generally assumed to be 5-10mmHg in ventilated infants.
  • It is important to know the systemic blood pressure to determine whether PAP is above systemic BP.

Ductal Flow

PPHN - bidirectional PDA flow.jpg (199362 bytes)
  • This baby had severe PPHN (with RV pressures calculated to be 74mmHg above RA pressure), although his requirement for ventilatory support was minimal.  The Doppler gate is in the PDA.  Left-to-right flow (above the line) and right-to-left (below the line) are seen.

TPV/RVET Ratio and RPEP/RVET Ratio

Atrial Shunting

Other Shunts

Click on the thumbnail image to see a larger image
PPHN - VSD shunt.jpg (118656 bytes)
  • Other shunts can be used to estimate RV pressure.
  • The image to the left demonstrates a subcostal view of the heart focusing on the interventricular septum.  This baby did not have a duct, nor any evidence of tricuspid regurgitation from which to estimate RV pressure.  However, he was found to have a small VSD (seen as the reddish shape in the middle of the "wedge").  The redness of the image demonstrates left-to-right flow through the small VSD at the point in time that the image was taken.
    • Doppler interrogation of the flow through the VSD demonstrated pure left-to-right flow, and the peak velocity was 2.2 m/sec.  This indicated that the peak LV pressure was at least 19 mmHg above RV pressure.

Cardiac Function and Output

PPHN - TAPVD  Parasternal.jpg (110788 bytes)

PPHN - TAPVD Apical.jpg (55679 bytes)

Click on the images to the left to see larger images
  • TAPVD can be missed when assessing infants with presumed PPHN. The top images on the left are taken in the parasternal long axis view.  The RV is anterior to the LV.  The ascending aorta is labelled as AO.  The RV is enlarged and the LV is underfilled and "squashed".  This is common in severe PPHN.
  • However, the lower image shows the apical 4-chamber view.  The RA and RV are grossly dilated, the LV is small, and another structure - the pulmonary venous chamber, PVC,  - is seen (usually not as obviously as in this image).
    • The PVC represents the confluence of the abnormal pulmonary veins draining into the systemic venous circulation (which can be at the level of portal vein, coronary sinus, RA directly, or to an ascending vertical vein and then innominate vein).
  • Demonstration of a left-to-right shunt at atrial level essentially excludes TAPVD

References

1

Skinner J, Alverson D, Hunter S (eds).  Echocardiography for the neonatologist.  Churchill Livingstone 2000.