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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 5, September/October 2018
274
AFRICA
were chosen from inside the camps of people who were internally
displaced because of Darfur political conflict. Table 1 details
the features of the communities in Khartoum and Niyala (data
obtained from local authorities).
The study protocol conformed to the ethical guidelines of the
1975 Declaration of Helsinki and was approved by the research
ethics committee of the University of Khartoum. Approval was
obtained from the school health department of the Ministry of
Health as well as the school and camp authorities. Informed
consent forms were given to the children’s families and only those
who consented were screened.
A sample size of 3 000 subjects was calculated for each
site based on an estimated echo prevalence of 3%
10
and
non-respondent rate of 5%. In both study areas, all the primary
schools were listed. Fifteen schools were selected randomly in
Khartoum and eight in Niyala, Darfur, with equal numbers of
girls’ and boys’ schools. In both areas, school grades four to eight
were chosen (age 10 to 15 years). All the pupils were invited to
participate.
Two HHE machines (V scan, General Electric) were used. This
machine has a single probe with a frequency of 1.7 to 3.4 MHz.
It has storage capacity and a battery that lasts about 2.5 hours.
For the Khartoum study, four paediatric cardiology fellows
were trained in using the V scans based on the WHF guidelines,
with the exception of continuous-wave Doppler, which is not
available in the HHE.
6
Three views were used (parasternal
long-axis, four-chamber and four-chamber with aorta), all done
without and then with colour Doppler. The fellows took the
measurements and recorded abnormal echo studies for offline
review by another cardiologist.
For the Niyala, Darfur study, two medical officers were
trained in using the V scan. A simplified ‘one-view’ protocol
utilising the parasternal long-axis view was adopted following
the publication of an article that showed its high diagnostic
ability.
11
Four images were recorded, two without and two with
colour Doppler. All the studies were recorded and stored to be
reviewed offline by two paediatric cardiologists.
An abnormal result was defined by the modified WHF
criteria as follows:
•
Definite RHD:
–– If there is pathological regurgitation plus two morphologi-
cal criteria
–– If there is borderline disease of both mitral and aortic
valves
•
Pathological regurgitation is defined as:
–– mitral regurgitation (MR) jet ≥ 2 cm
–– aortic regurgitation (AR) jet ≥ 1 cm
•
Morphological criteria are defined as:
–– For the mitral valve: anterior mitral valve leaflet > 3 mm,
chordal thickening, restricted leaflet motion and excessive
leaflet tip motion in systole
–– For the aortic valve the morphological criteria include
irregular thickening, coaptation defect, restricted leaflet
motion and prolapse.
The main difference between this method and the original WHF
criteria is that we do not use continuous Doppler as the HHE
does not have this feature.
•
Borderline RHD:
–– Pathological regurgitation without morphological criteria
–– Two of the above morphological criteria without patho-
logical regurgitation.
School children with abnormal results were called through
their school administrators and the families were informed.
Transportation was arranged to the hospital where a standard
echo (SE) study was performed for each child. Echo machines
used for SE were the Esaote My Lab 50 in Khartoum and the
Mandray machine in Darfur.
Two paediatricians from Niyala Hospital were trained in
RHD prevention, according to the national guidelines.
12
Lectures
were integrated into the routine training activities of the primary
healthcare personnel. Posters and pamphlets were distributed to
the health workers. Local radio and television programmes were
provided with a promotional video.
13
Statistical analysis
Data were analysed using percentages. Bias-adjusted kappa =
2 (Agreement 1) was used to assess agreement between HHE
and SE. The same test was used to determine the inter-observer
variation on a randomly selected sample of 28 echo studies.
14
Data were analysed using Stata version 14.
15
Results
In Khartoum, 3 000 school children were screened using HHE.
Seven cases were found to have RHD, six were borderline and
one was definite (ratio of definite-to-borderline RHD of 0.16:1).
Using SE, two cases were found to have congenital heart disease
(partial atrioventricular septal defect in both), one had mitral
valve prolapse, one physiological MR and two were normal. One
was found to have definite RHD (pathological MR plus two
morphological criteria). The prevalence of RHD in Khartoum
was 0.3/1 000 children. The average time to complete the HHE
study was 10 minutes.
In Niyala, Darfur, due to technical problems with electricity
supply (see limitations), we managed to screen only 1 515 school
children. On reviewing the echo studies, 17 were excluded
because of inadequate imaging quality. Out of the remaining
1 498 studies, 59 cases were positive for RHD; 44 had definite
and 15 borderline RHD. The ratio of definite-to-borderline
RHD was 2.9:1. The average time to complete the echo study
was four minutes.
Table 1. Demographic features of the two sites
Demographic
features
Khartoum site
Niyala site
Location
Mayo area 9 km south of
Khartoum
Ottash and Deraig camps for
displaced people, 6 km south
of Niyala, South Darfur
Population
37 000
128 460
Average income
(US$/month)
66
30
Type of work
Marginal business
Seasonal farmers
Average number of
family members
11
10
Type of house
50% non-brick
100% non-brick
Piped water
Available
Not available
Electricity
Available
Not available
Number of health
facilities
20 units
6 units
Population/health
facility ratio
1 850:1
21 410:1