Introduction
Pulmonary hypertension (PHTN) is a disease of small pulmonary arteries
characterized by a progressive increase in pulmonary vascular resistance
leading to right ventricular failure.
The World Health
Organization (WHO) defined a classification
for pulmonary
hypertension diagnosis , based on the cause of the disease. PHTN is
defined as a mean pulmonary artery pressure (mPAP) of 25 mm Hg at rest
in Right Heart cath (RHC). PHTN results in right ventricular (RV)
pressure overload, which ultimately leads to right-heart failure and
death(1,2). The gold standard for the diagnosis of PHTN is right heart
catheterization (1). Due to its invasive
character and lack of access to the required equipment, RHC cannot be
used as a routine screening method. (2,
3).
Echocardiography is an affordable technique and is widely used in
diagnosis of cardiac abnormalities in PHTN patients. It has been shown
that echocardiography has an acceptable accuracy in detecting mPAP and
thus can be used as a screening tool for PHTN in suspicious cases
(4). The current advancements in Doppler
echocardiography has made it more suitable for the assessment of mPAP
(4). The PAP can be determined based on
various echocardiographic parameters including pulmonic valvular
regurgitation, acceleration time of Pulsed-wave Doppler interrogation of
the RV outflow tract and systolic TR jet(which is used to estimate
systolic pulmonary artery pressure ,SPAP), too. SPAP is achieved only
based on TR jet. TR jet might result in inaccurate SPAP due to trivial
regurgitant jet, suboptimal continuous-wave, unclear jet envelope and
severe TR, where the peak velocity may not reflect the true RV–right
atrial pressure (RAP)gradient because of early equalization of RV
pressure and RAP. So, echocardiography was shown to underestimate or
overestimate SPAP compared to invasive methods
(5). Based on the limitations in the
methods for assessing the modalities for detecting PAP, other modalities
should be tested to identify PAP with an acceptable accuracy.
It was previously reported that flow velocity, waveform morphology of
middle hepatic vein (MHV) and inferior vena cava (IVC) were
significantly related to RA pressure (6).
The hepatic vein has a smaller angle compared to the IVC
(6). Therefore, echocardiographic
parameters pertaining to hepatic vein may serve as easy measures for
assessing right atrial (RA) pressure (3,
7). It was previously shown that chronic
pulmonary hypertension increases the sensitivity of HV systolic filling
fraction in detecting cardiac chamber dysfunction
(8, 9). The
aim of this study was to identify the proper hepatic vein Doppler
echocardiographic parameters in predicting PHTN.