Cardiovascular Journal of Africa: Vol 30 No 1 (January/February 2019)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 30, No 1, January/February 2019

AFRICA

Bernoulli’s equation then allows for the estimation of the RVSP,

taking into account right atrial pressure (RAP):

RVSP

TR MIG

RAP.

RAP is estimated from the inferior vena cava (IVC) calibre and

respiratory collapsibility (Table 1, Fig. 3B). In the absence of

pulmonary stenosis and acute right HF, the estimated RVSP is

assumed to equal the pulmonary artery systolic pressure.

To avoid errors in the measurement of RVSP, it is mandatory

to observe some conditions, including accurate measurement of

the IVC, avoiding measuring over-gained (shaggy) signals (Fig.

3A). If the heart rhythm is irregular, it is recommended that three

to five consecutive cycles be measured and the mean of these

cycles be recorded.

In patients with PH, Doppler echo also contributes to the

evaluation of the RV systolic function through measurement

of the tricuspid annular plane systolic excursion movement

(TAPSE). TAPSE represents the distance of systolic excursion of

the RV annular plane towards the apex. As shown in Fig. 3D, it is

obtained using an M-mode cursor passed through the tricuspid

lateral annulus in the four-chamber view and measuring the

amount of longitudinal displacement of the annulus at peak

systole.

In the PAPUCO registry,

Doppler echo findings showed that

left ventricular (LV) function was moderately impaired overall

(median LV ejection fraction 46%) (Fig. 3C). As expected,

RVSP was markedly elevated (median value 58 mmHg), with

concurrent moderate to severe right atrial (58%) and right

ventricular (55%) hypertrophy a common feature. Only one-third

of cases (

69; 33%) showed no evidence of right atrial or

ventricular enlargement. Overall, 78 patients (37%) presented

with a diagnosis of right HF based on TAPSE movement < 15

mm (Fig. 3D) plus one or more clinical signs of HF.

The LHD aetiology

of PH is suggested by (1) presence of

heart disease as suggested by a dilation in the cavities (Fig. 3E),

presence of heart valve disease or abnormal contractility, and (2)

arguments suggestive of an elevation of left ventricular filling

pressure, such as left atrial dilation (Fig. 3E) or a mitral Doppler

restrictive pattern (Fig. 3F). In the subgroup of patients with

PHLHD,

aetiologies were predominantly hypertensive HF with

reduced or preserved ejection fraction, dilated and peripartum

cardiomyopathy and rheumatic valvular heart disease. Left

atrium size and TAPSE were predictors of RVSP in these

patients, and RVSP predicted short-term hospitalisations but

not mortality.

We therefore recommend that an estimated RVSP greater

than 35 mmHg in SSA should warrant further evaluation for PH

in patients with suggestive PH in step 1 and/or 2 (Fig. 1). Finally,

Doppler echo can clearly help identify possible aetiologies

of PH, and particularly PHLHD (Table 2), anticipating the

contribution of other tests.

Step 4: other investigations

A careful selection of other tests can contribute to establishing

a diagnosis of PH in patients residing in low-income countries

such as SSA. The utilisation of these other investigations will

depend on both the results of the above initial tests and the

clinical context. Given the high burden of HIV/AIDS in the

region as well as its contribution in the PAPUCO registry

(22%), it is reasonable to screen all patients with PH for HIV.

Other tests, such as abdominal ultrasound, liver-function test,

high-resolution computerised tomography (CT), CT pulmonary

angiography, ventilation/perfusion lung scan, and electrophoresis

of haemoglobin will be guided by the clinical context. It is only

after these steps have been completed and once a definitive

diagnosis of PH has been reached and potential underlying

co-morbidities or causes identified, that classification within an

appropriate aetiological group must be considered (Fig. 4).

We acknowledge classification difficulties in SSA and other

low-income countries, especially in the absence of RHC and

Table 1. Estimation of right atrial pressure from inferior vena cava

calibre and respiratory collapsibility. Adapted from Beigel

et al

Estimated RAP (mmHg) IVC diameter (cm)

IVC collapse with

inspiration (sniff)

< 2.1

50%

< 2.1

< 50%

≥

2.1

50%

≥

2.1

< 50%

RAP, right atrial pressure; IVC, inferior vena cava.

Table 2. Possible causes of pulmonary hypertension identified by

echocardiography with relevance to sub-Saharan Africa

Predisposing conditions for pulmonary hypertension

• Valvular disease [mitral (aortic) stenosis/regurgitation, prosthetic valve

dysfunction]

• Left ventricular systolic dysfunction (including hypertensive heart failure,

dilated cardiomyopathy, peripartum cardiomyopathy, myocardial infarction)

• Left ventricular diastolic function (including ischaemic heart disease, hyper-

tensive heart disease, hypertrophic cardiomyopathy, Fabry’s disease, infiltra-

tive cardiomyopathies)

• Other obstructive lesions (coarctation, supravalvular aortic stenosis, sub-

aortic membrane, cor triatriatum)

• Congenital disease with shunt [atrial (ventricular) septal defect, coronary

fistula, patent ductus arteriosus, anomalous pulmonary venous return]

• Pulmonary embolus (thrombus in inferior vena cava, right-sided cardiac

chamber, or pulmonary artery; tricuspid or pulmonic valve vegetation)

• Pulmonary vein thrombosis/stenosis

Findings that suggest specific disease entity

• Left-sided valve changes (systemic lupus erythematous, anorexigen use)

• Intra-pulmonary shunts (hereditary haemorrhagic telangiectasia)

• Pericardial effusion (idiopathic pulmonary arterial hypertension, systemic

lupus erythematous, systemic sclerosis)

Group 3

PH due to lung

disease and/or

hypoxia.

e.g. COPD or

tuberculosis

Group 1

Pulmonary arterial

hypertension.

e.g. HIV-associated PH

Group 2

PH due to left heart disease.

e.g. mitral stenosis due to

rheumatic heart disease

Group 5

PH with unclear or

multifactorial mechanism.

e.g. endomyocardial fibrosis

Group 4

Chronic thromboembolic PH.

e.g. chronic pulmonary

embolism

Fig. 4.

World Health Organisation classification of pulmonary

hypertension with relevant examples for sub-Saharan

Africa.