DOPPLER ECHOCARDIOGRAPHIC ASSESSMENT OF PULMONARY ARTERY PRESSURE IN CHILDREN WITH SICKLE CELL ANAEMIA IN STEADY STATE AND THEIR HEALTHY CONTROLS AT THE LAGOS STATE UNIVERSITY TEACHING HOSPITAL IKEJA

Abstract

Pulmonary artery hypertension (PAH) is a known complication of patients with sickle cell
disease (SCD). The prevalence of PAH has been reported to be high in children with SCD in
developed countries. The mortality rate of patients with SCD who develop PAH is said to be
40% at 24 to 40 months after diagnosis. In Sub-Saharan Africa, particularly Nigeria, where
the prevalence of SCD is high, with as many as six million Nigerians afflicted with the
disease, there is a dearth of data on the prevalence of PAH in children with SCD. PAH may
be a likely contributor to the unacceptably high mortality rate of children with SCD in Africa.
The aim of the study was to determine the pattern of pulmonary artery pressure in children
with sickle cell anaemia (SCA) aged one year to twelve years in steady state and their healthy
controls using Doppler echocardiography at the Lagos State University Teaching Hospital
(LASUTH), Ikeja.
The present study was analytical, comparative and cross sectional. It was carried out at
LASUTH over a period of seven months (31st August 2015 through 31st March 2016). A total
of 400 children, aged one to twelve years were recruited following parental consent and
assent. Two hundred children with sickle cell disease in steady state and 200 age and sex
matched children with haemoglobin genotype AA who served as controls were studied. All
subjects and controls had Doppler echocardiography performed on them by the author. Other
laboratory parameters (complete blood count and lactate dehydrogenase activity) were
obtained using standard techniques. PAH was defined as a pulmonary artery systolic pressure
of ≥ 30 mm Hg at rest derived from the tricuspid regurgitant velocity (TRV) measured from
Doppler echocardiography. This corresponds with TRV value of ≥ 2.5m/s.
The prevalence of PAH in children with SCA was 8% (n = 16). None of the controls had
PAH. The youngest subject with PAH was aged two years. The overall mean pulmonary
artery pressure of children with SCA was significantly higher than that of controls (18.54 ±
5.81 mm Hg vs. 13.76 ± 5.71 mm Hg, p = 0.00). The prevalence of PAH in children with
SCA demonstrated an increase in trend with age. There was a significant relationship
between PAH and reticulocytosis in children with SCA in steady state. (p= 0.020). There was
no significant relationship between PAH and the other measured laboratory indices
(haemoglobin concentration, white blood cell count, platelet count and lactate dehydrogenase
activity) in children with SCA in steady state. (p > 0.05).
In conclusion, the prevalence of PAH in children with SCA in steady state is high. This
complication was noticed as early as the second year of life. It is recommended that all
children with SCA should have periodic Doppler echocardiography for early detection of
PAH.

DOPPLER ECHOCARDIOGRAPHIC ASSESSMENT OF PULMONARY ARTERY PRESSURE IN CHILDREN WITH SICKLE CELL ANAEMIA IN STEADY STATE AND THEIR HEALTHY CONTROLS AT THE LAGOS STATE UNIVERSITY TEACHING HOSPITAL IKEJA