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Thorax 1989;44:396-401
Detection of pulmonary hypertension by Doppler
echocardiography of the inferior vena cava in chronic
airflow obstruction
J P LAABAN, B DIEBOLD, M LAFAY, J ROCHEMAURE, P PERONNEAU
From the Department of Pneumology and Intensive Care, Hotel-Dieu, and Unite Inserm 256, Broussais
Hospital, Paris, France
ABSTRACT Pulsed Doppler echocardiography of the inferior vena cava is an accurate method for the
diagnosis of tricuspid regurgitation and impaired right ventricular compliance, two features of
pulmonary hypertension. The purpose of this study was to assess the value of Doppler echocardiography of the inferior vena cava for the detection of pulmonary arterial hypertension in patients with
chronic obstructive lung disease. Pulsed Doppler echocardiography of the inferior vena cava and
right heart catheterisation were performed in 29 patients with severe chronic obstructive lung disease.
The mean pulmonary arterial pressure was 27 (10) mm Hg for the entire group; 62% of patients (18/
29) had pulmonary arterial hypertension (mean pulmonary arterial pressure > 20 mm Hg). An
adequate Doppler signal could be obtained in 25 of the 29 patients (86%). Pulsed Doppler
echocardiography of the inferior vena cava gave normal results in 10 patients and disclosed tricuspid
regurgitation in seven patients, impaired right ventricular compliance in seven patients, and both of
these abnormalities in one patient. An abnormal Doppler echocardiogram of the inferior vena cava
(tricuspid regurgitation or impaired right ventricular compliance, or both) predicted the presence of
pulmonary arterial hypertension with a sensitivity of 87% and a specificity of 80%. These results
suggest that pulsed Doppler echocardiography of the inferior vena cava may be a useful though
imperfect method of detecting pulmonary arterial hypertension in patients with chronic obstructive
lung disease.
Introduction
The presence of pulmonary arterial hypertension in
patients with chronic obstructive lung disease is
associated with a poor prognosis.' The survival rate of
such patients may be improved by long term
domiciliary oxygen therapy.2 Right heart catheterisation is the reference method for the diagnosis of
pulmonary arterial hypertension but this invasive
technique is not always well tolerated in patients with
chronic obstructive lung disease and cannot be
repeated frequently to detect pulmonary arterial
hypertension. There is a need for non-invasive methods to allow the accurate detection of pulmonary
Accepted 6 February 1989
Address for reprints: Dr J P Laaban, Department of Pneumology and
Intensive Care, Hotel-Dieu, I Place du Parvis Notre-Dame, 75181
Paris Cedex 04, France.
396
arterial hypertension in these patients. Electrocardiography3 and thallium-201 myocardial scintigraphy4
are limited by poor sensitivity, especially in patients
with moderate pulmonary arterial hypertension, and
right ventricular radionuclide angiography lacks
specificlity for detecting pulmonary arterial hypertension in patients with chronic obstructive lung disease.'
The value of echocardiography is very limited in these
patients because of the poor penetration of ultrasound
as a result of lung overinflation.67 Recently cardiac
continuous wave Doppler ultrasound has been used to
estimate the systolic pulmonary artery pressure from
the velocity of a tricuspid regurgitation jet in patients
with acquired and congenital heart diseases.8 In a high
percentage of patients, however, even those with
pulmonary arterial hypertension, the absence of
tricuspid regurgitation precludes the estimation of
pulmonary artery pressure.9
Pulsed Doppler recordings of inferior vena caval
blood flow offer an indirect approach to the assessment of right heart haemodynamics. They have been
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Detection ofpulmonary hypertension by Doppler echocardiography of the inferior vena cava
397
shown to be accurate for the diagnosis of tricuspid patients a suitable signal cannot be obtained within the
insufficiency'0" and impaired right ventricular com- inferior vena cava. In these circumstances the flow of a
pliance.'2 As these recordings are based on a subcostal suprahepatic vein may be recorded. The suprahepatic
view they could be of value in patients with chronic veins lie more superficially and their flow pattern has
obstructive lung disease, in whom parasternal views the same characteristics as that of the inferior vena
are difficult to achieve. The aim of this study was to cava. As these velocities vary with intrathoracic
evaluate the feasibility of this recording in patients pressures, in particular with respiration, the flowwith chronic obstructive lung disease, to analyse velocity tracings must be recorded during an open
changes in inferior vena caval blood flow, and to study glottis apnoea at the end of expiration.
the relation between these changes and pulmonary
ANALYSIS OF THE INFERIOR VENA CAVAL FLOW
hypertension.
VELOCITY
Methods
PATIENTS
The present study included 29 consecutive patients
with chronic obstructive lung disease (20 of them men)
who were referred for right heart catheterisation. The
patients had either chronic bronchitis, characterised
by cough and sputum during at least three consecutive
months for each of two consecutive years, or
emphysema, characterised by dyspnoea with
radiological evidence of emphysema and functional
evidence of airways obstruction (FEV,/FVC < 55%).
Three patients had left heart disease also, cardiomyopathy in two and prior myocardial infarction
in one. No patient had rheumatic or congenital heart
disease. Atrial fibrillation was present in two patients.
The patients were in a stable condition during the
previous three weeks and at the time of the study.
The patients had a mean (SEM) age of 61 (I 1) years
and their forced expiratory volume in one second
(FEV,), as mean (SEM) % of predicted value, was 40
(21), forced vital capacity (FVC) 73 (15) (FEV,/FVC
ratio = 40 (14)), residual volume 142 (52), and total
lung capacity 98 (18); arterial oxygen tension (Pao2)
was 8 5 (1 5) kPa, arterial carbon dioxide tension
(Paco2) 5*7 (0.9) kPa. Seven of the 29 patients (24%)
had had right heart failure in the past and 18 (62%)
had had an episode of acute respiratory failure.
Inferior vena caval blood flow was also studied in 10
healthy subjects.
DOPPLER EXAMINATION TECHNIQUE
We used a pulsed Doppler velocimeter combined with
a two dimensional echocardiography (CGR Sonel
3OOOc-Dop 150). The emission frequency of the
transducer is 3 MHz. The depth of the sample volume
can be set from 3 to 15 cm according to the pulse
repetition rate.
The patient is placed in the supine position. The
transducer is located on the epigastric area. The
ultrasonic beam is oriented posteriorly and to the right
to visualise the inferior vena cava behind the liver.
Inferior vena caval flow is regulated by the heart and
by respiration, increasing during inspiration. In some
The normal inferior vena caval flow is away from the
transducer and corresponds to a negative wave. The
normal flow has three components'": a predominantly
negative systolic wave (s) due to atrial relaxation and
lowering of the ventricular floor, a negative diastolic
wave (d), which has a smaller amplitude and corresponds to the passive filling of the right ventricle, and a
positive flow reversal wave in late diastole, which is
due to atrial contraction and occurs immediately after
the P wave of the electrocardiogram. In the case of
atrial fibrillation, the relative amplitude of s is smaller
and the end diastolic reverse flow disappears. There is
a delay between the cardiac events recorded on the
electrocardiogram and the inferior vena caval flowvelocity owing to venous compliance.
In the case of mild tricuspid regurgitation the
amplitude of the antegrade systolic flow-velocity (s)
decreases. When tricuspid regurgitation is more
severe, the normal negative systolic wave is replaced
by a retrograde positive systolic wave'0 " (corresponding to the T wave of the ECG), which occurs either in
late systole (moderate tricuspid regurgitation) or
throughout systole (severe tricuspid regurgitation).
In the presence of impaired right ventricular compliance the normal negative diastolic wave is replaced
by a retrograde positive diastolic wave, which starts
before the P wave of the electrocardiogram with sinus
rhythm or before the QRS complex with atrial
fibrillation.'2 Impairment of right ventricular compliance was assessed subjectively as moderate or severe
according to the importance of the positive diastolic
flow.
CARDIAC CATHETERISATION
Right heart catheterisation was performed with a
Swan-Ganz catheter. The curve of pulmonary arterial
pressure was recorded during open glottis apnoea at
the end of expiration. Pulmonary arterial pressure was
averaged over five beats in sinus rhythm. In atrial
fibrillation beats with R-R intervals representative for
the mean heart rate were chosen. Pulmonary arterial
hypertension was defined as a mean pulmonary
arterial pressure above 20 mm Hg. Cardiac output (Q)
was measured by the thermodilution technique with
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398
injection of iced saline solution and a commercially
available computer (Edwards Laboratories COM 1).
The haemodynamic and Doppler studies were performed within three days of each other, when the
subject was clinically stable and with treatment
unchanged. Cardiac catheterisation and the echo
Doppler study were performed with the subject
supine, at rest, and without sedation. The patients'
drugs were continued as usual.
The physician performing the catheterisation was
unaware of the results of the Doppler study. Analysis
of the inferior vena cava Doppler was made (1) by the
physician performing the Doppler examination, who
did not know the haemodynamic results, and (2) in a
blind manner by a second physician from the Doppler
traces alone.
Results
The results of the haemodynamic study are summarised in table 1. The mean (SD) value of mean
pulmonary arterial pressure for the entire group was
27 (10) mm Hg. Eighteen of the 29 patients (62%) had
pulmonary arterial hypertension as defined.
The results ofthe pulsed Doppler echography of the
inferior vena cava are summarised in table 2. There
was no discordance between the Doppler analyses of
the two physicians concerning the quality of traces, the
diagnosis of tricuspid regurgitation and impaired right
ventricular compliance, or the evaluation of the
severity of these conditions. The flow-velocity curves
of the inferior vena cava were inadequate for analysis
Table 1 Results ofhaemodynamic study (mean (SD)
values)
Patients with Patients without
PAH
PAH(n = 11)
All patients
(n = 29)
(n
PAP(mm Hg)
PAP, (mmHg)
PAP (mm Hg)
PWP(mm Hg)
RVPSP (mm Hg)
RVEDP (mm Hg)
(mm HS)
CI (1/min/m')
APR (dyn/s/cm- 5)
TPR (dyn/s/cm-')
27(10)
40(16)
=
18)
16(2)
24(4)
33(9)
49(11)
15(8)
8(2)
19(8)
11(5)
41(19)
5 (4)
6(4)
3-1(07)
278 (213)
434 (208)
9(3)
24(5)
3(3)
4(2)
3-5(1)
124 (22)
248 (43)
11(6)
48(13)
7(4)
7(4)
3(0-7)
353 (215)
540(188)
PAP-mean pulmonary artery pressure; PAP,-systolic pulmonary
PAPd-diastolic pulmonary artery pressure;
PWP-mean pulmonary wedge pressure; RVPSP-right ventricular
peak systolic pressure; RVEDP-right ventricular end diastolic
pressure; RAP-mean right atrial pressure; Cl-cardiac index (CI =
t/body surface area); 0-cardiac output (1/min); APR-pulmonary
Laaban, Diebold, Lafay, Rochemaure, Peronneau
Table 2 Results ofpulsed Doppler echography ofinferior
vena cava (numbers ofpatients)
Inadequate Doppler signal
Adequate Doppler signal
Doppler findings:
Normal
IRVC
TR
IRVC and TR
Patients
(n = 29)
Control subjects
(n = 10)
4/29 (14%)
25/29 (86%)
0
10/10 (100%)
10
7
10
0
0
0
7
1
IRVC-impaired right ventricular compliance; TR-tricuspid
regurgitation.
in four patients because of obesity in two cases and
impossible apnoea in one. In 25 of the 29 patients
(86%) the Doppler signal of the inferior vena cava was
adequate for analysis. It was normal in 10patients and
showed impaired right ventricular compliance in
seven, tricuspid regurgitation in seven, and both in one
patient. In all patients with impaired right ventricular
compliance, the impairment of right ventricular compliance was moderate. Tricuspid regurgitation was
mild in five patients and moderate in three.
In 25 patients we were able to compare the results of
the pulsed Doppler echography of the inferior vena
cava with the haemodynamic data (table 3). Among
the 15 patients with pulmonary arterial hypertension
the results of the Doppler study were abnormal in 13
patients, showing impaired right ventricular compliance or tricuspid regurgitation or both. The inferior
vena caval flow-velocity tracings were also abnormal
in two of the 10 patients without pulmonary arterial
hypertension. The sensitivity of pulsed Doppler
echocardiography of the inferior vena cava for the
diagnosis of pulmonary arterial hypertension (mean
pulmonary arterial pressure > 20 mm Hg) therefore
was 87% and the specificity 80%. The positive predictive value was 87% and the negative predictive value
80%. The true sensitivity for detecting pulmonary
arterial hypertension for the whole group, including
the patients where a satisfactory trace was not
obtained, was 72% and the true specificity 82%.
Table 3 Comparison ofpulsed Doppler echography ofthe
inferior vena cava and haemodynamicfindings in the 25
patients with chronic obstructive lung disease who had an
adequate Doppler signal (numbers ofpatients)
artery pressure;
arterial resistance (APR =
pulmonary resistance (TPR
hypertension.
_PAP
x
PAP
=
PWP
x
80); TPR-total
80); PAH-pulmonary artery
Impaired right ventricular
Normal inferior vena compliance and/or
cavalflow-velocity tricuspid regurgitation
P > 20mm Hg
(n= 15)
2(13%)
PAP < 20 mm Hg
=
(n 10)
8(80%)
Sgnificant difference (p < 0-01, x2 test).
PAP-mean pulmonary artery pressure.
13(87%)*
2(20%)*
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Detection ofpulmonary hypertension by Doppler echocardiography of the inferior vena cava
399
is
scintigraphy
myocardial
of
thallium-201
There were two false positive findings. In the first value
case moderate impaired right ventricular compliance limited by the low sensitivity (65%) of the method in
was observed in only two complexes. In the second patients with moderate pulmonary arterial hypertencase very mild tricuspid regurgitation was recorded. In sion.'
The rationale for studying inferior vena caval blood
one of the two patients with false negative findings, the
mean pulmonary arterial pressure was only 21 flow was that this vessel is easily visualised in most
patients with chronic obstructive lung disease with a
mm Hg.
In the 10 healthy subjects the flow pattern of the subcostal view and that inferior vena caval blood flow
depends directly on right heart haemodynamics.
inferior vena cava was normal.
Diebold et al,' using pulsed Doppler echocardiography of the inferior vena cava in 70 patients, mainly
Discussion
with valvular diseases, undergoing selective right
Right ventricular dysfunction as a result of pulmonary ventricular angiography, showed that the method had
arterial hypertension is a common complication of a sensitivity of 89% and a specificity of 100% for the
chronic obstructive lung disease.'3 The presence of diagnosis of tricuspid regurgitation. If only moderate
pulmonary arterial hypertension has an important to severe tricuspid regurgitation was considered, the
prognostic value'4 as well as therapeutic implications sensitivity and specificity were both 100%. This Dopfor this disease. Patients with chronic obstructive lung pler method also allows the extent of tricuspid regurdisease and pulmonary arterial hypertension may gitation to be quantified. Flow in the superior vena
benefit from oxygen therapy.2 Vasodilator treatment cava may be used to detect tricuspid regurgitation20
in patients with chronic obstructive lung disease may but the reported sensitivity and specificity are lower
have beneficial haemodynamic effects when adminis- than those reported for inferior vena caval blood flow
tered acutely. 5 The success of long term vasodilator studies. Diebold et al 1 found a sensitivity of 90% and
treatment has not been proved but may depend on the a specificity of 100% for Doppler echocardiography of
early detection of pulmonary arterial hypertension.'6 the inferior vena cava for detecting impaired right
Most patients with chronic obstructive lung disease ventricular compliance in cases of pericardial effusion.
The flow-velocity curve of the inferior vena cava
when clinically stable have mild to moderate pulmonary arterial hypertension with mean pulmonary artery was adequate for analysis in 25 of the 29 patients in our
pressures ranging from 20 to 35 mm Hg.'4 The fact series (86%), despite the fact that all had severe
that pulmonary hypertension is relatively mild is one chronic obstructive lung disease. The Doppler detecof the main difficulties encountered in the non-invasive tion of tricuspid regurgitation or impaired right
diagnosis of pulmonary arterial hypertension in ventricular compliance or both allowed the prediction
chronic obstructive lung disease.'7 There is a need of pulmonary arterial hypertension in our patients
therefore for a sensitive and reliable non-invasive with a sensitivity of 87% and a specificity of 80%.
Possible criticisms of our methods need to be
screening tool for detecting moderate degrees of
pulmonary arterial hypertension in patients with considered. Firstly, the Doppler and haemodynamic
studies were not simultaneous, though the delay
chronic obstructive lung disease.
Several methods can be used to detect pulmonary between the two examinations was always less than
arterial hypertension in chronic obstructive lung dis- three days and there was no change in clinical
ease. The ECG criteria of right ventricular hypertro- condition or in treatment between the two studies;
phy3 have high specificity ( > 90%) but low sensitivity secondly, this Doppler method does not allow a direct
(<50%). The chest radiographic assessment of the diagnosis of pulmonary arterial hypertension but
diameter of the right descending pulmonary artery is detects its effects on the right ventricle-that is,
limited by low sensitivity (68%) and specificity (65%) tricuspid regurgitation and impaired right ventricular
in detecting moderate pulmonary arterial hyperten- compliance, which we assume to be related to right
sion.'6 M mode echocardiographic assessment of pul- ventricular dilatation and hypertrophy respectively;
monary arterial hypertension is limited by poor visual- thirdly, Doppler echocardiography of the inferior
isation of the right cardiac structures in most patients vena cava does not allow a quantitative evaluation of
with chronic obstructive lung disease.67 The feasibility pulmonary arterial hypertension or an estimation of
of two dimensional echocardiography is also low in its severity because the flow abnormalities (tricuspid
these patients,'8 but may be increased by combining regurgitation and impaired right ventricular comapical and subcostal four chamber views.'9 Radionu- pliance) were only mild or moderate in the patients
clide angiography in patients with pulmonary arterial with pulmonary arterial hypertension.
Several recent studies have shown that cardiac
hypertension shows a decrease in the right ventricular
ejection fraction but this method has poor specificity continuous wave Doppler ultrasound allows predic(55%) in chronic obstructive lung disease.5 The clinical tion of systolic pulmonary arterial pressure from the
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400
peak velocity of a tricuspid regurgitation jet.89 The
presence of cardiac Doppler detected tricuspid regurgitation, however, cannot be used to predict pulmonary arterial hypertension because it is observed in
many patients with normal pulmonary arterial pressure9 and it is often absent in patients with moderate
pulmonary arterial hypertension.8 In many patients
the absence of Doppler detected tricuspid regurgitation precludes a quantitative estimation of pulmonary
arterial pressure. Finally, poor conditions for
ultrasound transmission may be a serious limitation of
this method, which has not yet been validated in
patients with chronic obstructive lung disease: for
example, Peacock et al2' were unable to obtain an
adequate Doppler signal with this technique in 10 of 15
patients with chronic obstructive lung disease. It has
been recently shown that pulsed Doppler echocardiography of the pulmonary arterial trunk may be
useful for evaluating mean pulmonary arterial pressure in patients with chronic obstructive lung disease22
but the high value ofthe standard error ofthe estimate
precludes an accurate estimation of mean pulmonary
arterial pressure in a given patient.9
In conclusion, the echo Doppler of the inferior vena
cava showed abnormalities-that is, tricuspid regurgitation and impaired right ventricular compliancein a high percentage of patients with chronic obstructive lung disease and pulmonary arterial hypertension.
Our data suggest that this non-invasive method, which
is technically feasible in most patients with chronic
obstructive lung disease, could be of value in the
detection of pulmonary arterial hypertension in these
patients. Further studies, including large numbers of
patients with a wide range of severity of pulmonary
disease and pulmonary arterial hypertension, are
needed to determine the real value of this method.
This work was supported in part by a grant from the
Caisse Nationale d'Assurance Maladie des
Travailleurs Salaries.
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Detection of pulmonary
hypertension by Doppler
echocardiography of the inferior
vena cava in chronic airflow
obstruction.
J P Laaban, B Diebold, M Lafay, J Rochemaure and
P Peronneau
Thorax 1989 44: 396-401
doi: 10.1136/thx.44.5.396
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