Pulmonary Hypertension

Table of content (clickable):

Abnormal PA pressure defined (> 3 months of age):

Important resources:

Pre-capillary pulmonary hypertension official definition by catheterization (Pulmonary Arterial Hypertension) - click here for reference:

From: Changes in systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR) during gestation. (Lakshminrusimha and Saugstad, 2016).

Tricuspid regurgitation jet velocity gradient

During systole, tricuspid valve is closed (prevents backflow in RA)

As RV pressure starts rising and RV dilates, the annulus dilates and coaptation of valve becomes less competent. TR appears: blood flow from high pressure RV to low pressure RA generates a velocity of low.

Simplified Bernoulli equation tells you that :

TR obtained from the PLAX view and estimating RV-RA gradient of 33.6 mmHg - Providing an estimate of RV peak systolic pressure at 39 mmHg

TR obtained from the Apical view and estimating RV-RA gradient of 92 mmHg - Providing an estimate of RV peak systolic pressure at 97 mmHg (assuming RA pressure at 5 mmHg - likely underestimated in the context of RV failure leading to increased RA pressure)

Significant RV failure and dilation in the context of severe pulmonary hypertension.

As pressure rises on RV side (or pressure decreases on LV side), it can become iso-systemic (same as pressure on the LV compartment) or supra-systemic (higher pressure than on RV side).

Because there is a shared wall:

Isosystemic (>2/3 systemic) = Flat Interventricular septum at peak of contraction - D-Shape LV

Supra-systemic = Bowing septum into the LV cavity

With persistent increased afterload, RV hypertrophies and dilate

Case of acute pulmonary hypertension of the newborn (PPHN):

Parasternal long axis indicating underfilled LV (from low pulmonary vascular flow) and dilated RV outflow tract.

Sweep in parasternal short axis indicating almost pancaking of left ventricle. RV is dilated and septum is bowing at times in systole into the LV cavity at mid-papillary level.  LV is underfilled due to the persistence of increased pulmonary vascular resistance.

RV function is preserved despite increased pulmonary afterload. TR appears (mild) due to RV strain. 

RV peak systolic pressure is estimated using the TR jet peak velocity. RV-RA gradient of 58 mmHg (based on modified Bernouilli equation; 4 x 3.81 x 3.81). Assuming a RA pressure of about 5 mmHg, estimated peak systolic RV pressure of 63 mmHg. Assuming normal cardiac anatomy, systolic Pulmonary Arterial Pressure estimated at 63 mmhg. This patient had a systolic blood pressure (systemic) of 45 mmHg. Hence, supra-systemic pulmonary pressures. 

LV end-systolic eccentricity index as a way to quantify septal deformation

Eccentricity index (RV-LV Interaction: D1/D2) (Normal < 1.23)

RV/LV ratio (marker of RV dilation: D3/D2) (Normal < 1.00)


Jone JG, Ivy D, Frontiers in Pediatrics - November 2014 , Volume 2, Article 124

Nagiub M, Echocardiography 2015;32:819–833

The following image is from the above article. The article outlines:

From King ME et al. Circulation 1983. - "Marked exaggeration of this configurational change occurred in patients with right ventricular systolic hypertension (right ventricular systolic pressure greater than 50% systemic pressure), with progressive loss of curvature from end-diastole (0.45 ± 0.05) to end-systole (0.19 ± 0.06)."

RV-LV crosstalk

Pulmonary insufficiency - CW-Doppler

Same concept as TR

Diastolic pulm pressure (DPAP) estimated from pulm regurgitation jet from velocity of end-diastolic PI velocity

DPAP =  4 (end-diastolic PI velocity)2 + estimated RA pressure*

mPAP = 4 (early diastolic PI velocity)2 + estimated RA pressure*

*estimated RA pressure = RV end-diastolic pressure

PAAT/RVET - Pulmonary artery acceleration time / Right ventricular ejection time

From: Steven A. Goldstein MD; Echo in Pulmonary HTN, ASE - Georgetown University Medical Center MedStar Heart Institute

PV stenosis suspected if mean gradient ≥ 4 mmHg on echo

Right to left patent ductus arteriosus in the context of supra-systemic pulmonary pressure.

Other example of right to left PDA here.

CW-Doppler of the Right to Left PDA - Peak systolic gradient indicates that the PA pressure is 46 mmHg above the aortic pressure.

RV-LV cross-talk - Inter-Atrial shunt:

•LA-RA assessment of PFO/Atrial shunting reflects end-diastolic pressure relationships (influenced by MR-TR)

•With severe PH – RV diastolic dysfunction, increased RV end-diastolic pressures and bidirectional, eventually R to L shunt (and retrograde flow in hepatic veins with diastolic dysfunction).

Ventricular Septal Defect: 

Common Pulmonary Vasodilators:

New avenues under investigation for pulmonary arterial vasodilation

Acute vasoreactivity testing from PHA (Click here)

"Interpretation/Positive test: The 2009 ACC/AHA and 2015 ESC/ERS guidelines define a positive study based on a reduction in the mean pulmonary artery pressure of at least 10 mmHg to an absolute mean PA pressure of less than 40 mm Hg with a stable or improved cardiac output. Patients should have normal oxygen saturation prior to starting inhaled nitric oxide so that one can assess the true response on pulmonary vascular tone and not response to improved oxygenation."

"Acute vasoreactivity testing in children is undertaken to assess the response of the pulmonary vascular bed to pulmonary specific vasodilators. Similarly, the current practice in children with IPAH or familial PAH (isolated PVHD) is to use AVT to define the likelihood of response to long-term treatment with CCB therapy and for prognosis. There are 2 definitions of responders to AVT in IPAH or isolated PHVD, including 1) a decrease in mPAP of at least 10 mmHg to below 40 mmHg with a normal or increased increase in cardiac output; and 2) a decrease in mean PAP = 20% and increase or no change in CI and decrease or no change in PVR:SVR. AVT in children with PH associated with congenital heart disease (CHD) is undertaken to assess if the PVR will decrease sufficiently for surgical repair to be undertaken in borderline cases. In general, positive AVT for borderline cases with post tricuspid shunts is defined as decreases in PVRI to < 6-8 WUm2 or PVR:SVR <0.3. However, AVT is only one measure used to define operability and the whole clinical picture, the age of the patient and the type of lesion need to be taken into consideration. AVT may be studied with iNO (20–80 ppm), 100% oxygen, inhaled or intravenous PgI2 analogues, intravenous adenosine or sildenafil."

Apitz C, Hansmann G, Schranz D. Hemodynamic assessment and acute pulmonary vasoreactivity testing in the evaluation of children with pulmonary vascular disease. Expert consensus statement on the diagnosis and treatment of paediatric pulmonary hypertension. The European Paediatric Pulmonary Vascular Disease Network, endorsed by ISHLT and DGPK. Heart. 2016 May;102 Suppl 2:ii23-9. doi: 10.1136/heartjnl-2014-307340. PMID: 27053694. 

From this important resource here: https://heart.bmj.com/content/102/Suppl_2/ii23 :


Interesting article on Treprostinil pharmacokinetic review: https://pubmed.ncbi.nlm.nih.gov/27286723/ 

PPHNet individual membership form

March 27, 2023: You can now become an individual member to the Pediatric Pulmonary Hypertension Network (PPHNet). The membership form is attached here. You can also access it via the QR code or via the direct link here.

27 mars 2023: Vous pouvez maintenant devenir membre individuel du Pediatric Pulmonary Hypertension Network (PPHNet). Le formulaire d'adhésion est joint ici. Vous pouvez également y accéder via le code QR ou via le lien direct ici.

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