CARDIAC DIMENSIONS AND FUNCTIONAL PARAMETERS IN CHILDREN WITH HOMOZYGOUS SICKLE CELL DISEASE IN STEADY STATE AT THE OBAFEMI AWOLOWO UNIVERSITY TEACHING HOSPITALS COMPLEX , ILE –IFE

Abstract

Sickle cell anaemia (SCA) is the most common, severe and burdensome inherited disease
in Africa. Nigeria has the largest burden of SCA on the continent and in fact in the entire world.
In spite this, there are very few studies from this region on the effect of SCA on the heart, hence
this study. This study was a hospital-based, observational, descriptive, cross-sectional study.
Cardiac dimensions and functional parameters were determined by M-mode, 2
dimensional and Doppler echocardiography in 50 consecutive children aged 15 years and below
with sickle cell anaemia in steady state and compared with those of 50 age- and sex-matched
healthy controls with haemoglobin type AA (Hb AA).
Left ventricular (LV) end diastolic and systolic diameters of the subjects [mean (SD) =
4.33 (0.53) cm and 2.95 (0.42) cm] were significantly higher than those of the controls [mean
(SD) = 3.81 (0.41) cm and 2.61 (0.42) cm] (p < 0.001). There was a significant difference in the
interventricular septal diameter of both the subject and the control groups with that of the
subjects being larger [mean (SD) = 0.63 (0.17) cm and 0.54 (0.12) cm respectively] (p < 0.05).
Although, the mean left ventricular posterior wall diameter obtained in the subjects was
increased when compared with that obtained in the control group, the difference was not
statistically significant (p = 0.391).
There was a significant increase in the left ventricular mass and the left ventricular mass
indexed with height raised to the power of 2.7 of the subjects [mean (SD) = 84.73 (33.60) g and
53.55 (18.44) g/ m2.7 respectively] when compared with those of the control group [mean (SD) =
60.63 (22.35) g, and 32.59 (10.77) g/ m2.7 respectively] (p < 0.001).
The increase in cardiac dimensions was not restricted to the left ventricle. The left atrial
diameter and the aortic root diameter were significantly enlarged in the subjects [mean (SD) =3.29 (0.40) cm and 2.07 (0.32) cm respectively] when compared with the control group [mean
(SD) = 2.74 (0.39) cm and 1.93 (0.27) cm respectively] (p < 0.05).
Indices of LV systolic function i.e. fractional shortening (FS) and ejection fraction (EF)
were similar for both groups. The mean (SD) FS was 32.04 (6.44) percent for the subjects and
32.29 (5.66) percent for the controls (p = 0.835). The mean (SD) EF was 59.94 (9.19) percent for
the subjects and 60.86 (7.96) percent for the controls (p = 0.595).
The indices of LV diastolic function i.e. early mitral flow velocity (E wave) and late
mitral flow velocity (A wave) of the subject group [mean (SD) = 1.08 (0.18) m/ s and 0.58 (0.13)
m/s respectively] were significantly increased compared with the control group [mean (SD) =
0.94 (0.12) m/ s and 0.52 (0.07) m/ s respectively] (p < 0.001). However the E/ A ratio and
deceleration time were similar for both groups (p = 0.456 and p = 0.337 respectively).
The direct echocardiographic measurements in both groups correlated with age, (r > 0.5,
p < 0.001 in subjects and r > 0.4, p < 0.005 in controls). However, with the exception of the E
and A wave velocities of the control group (r = – 0.42, p = 0.002 and r = _ 0.36, p = 0.010
respectively), in which there was a significant negative correlation with age; all other functional
parameters did not show any significant relationship with age.
Linear regression analyses relating the body surface area with the various
echocardiographic parameters demonstrated a direct linear relationship between the aortic root,
the left atrial, septal and the left ventricular measurements, and the body surface area.
In conclusion, significant cardiac chamber enlargement was noted in the children with
sickle cell anaemia. In spite of this, systolic function of the left ventricle was normal. The
Doppler echocardiographic examination demonstrated that left ventricular diastolic filling
patterns are altered in the children with SCA and that these diastolic abnormalities are present
even in the absence of symptoms of heart failure. These abnormal patterns suggest intrinsic
myocardial abnormality in children with sickle cell anaemia and may prove to be early markers
of cardiac disease.

CARDIAC DIMENSIONS AND FUNCTIONAL PARAMETERS IN CHILDREN WITH HOMOZYGOUS SICKLE CELL DISEASE IN STEADY STATE AT THE OBAFEMI AWOLOWO UNIVERSITY TEACHING HOSPITALS COMPLEX , ILE –IFE