Download View Abstract

BIVENTRICULAR CARDIAC FUNCTION IN SUB-SAHARAN AFRICANS WITH SICKLE CELL DISEASE
Adebayo C. Atanda1, Yahya Aliyu1, Oluwafunmilayo A. Atanda3, Aliyu Babadoko4, Aisha I. Mamman4,
Zakari Y. Aliyu2,4,5
1-Howard University Hospital, Washington DC, 2- Vascular Medicine Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda,
Maryland; 3- Queens Heart Institute, Rosedale, New York.; 4-Department of Hematology and Blood Transfusion, Ahmadu Bello University, Zaria, Nigeria; 5- Center
of Sickle Cell Disease and Department of Medicine, Howard University, Washington, DC;
BACKGROUND
Various papers on sickle cell disease (SCD) in the USA reveals cardiac dysfunction. However, the highest
burden of SCD is in sub Saharan Africa. Amidst this population, use of hydroxyurea, blood transfusion
and iron overload is extremely limited, allowing for a unique assessment of biventricular (BV) function.
METHOD
We evaluated 208 hydroxyurea naive consecutive SCD patients aged 10-52 years at steady state and 94
healthy non-matched controls who were studied in Nigeria in a cross-sectional manner. SCD patients
were required to have electrophoretic and or liquid chromatography documentation of major sickling
phenotypes. Control group was required to have non-sickling phenotype. Cardiac measurements were
performed with transthoracic echo (TTE) for both systolic and diastolic functions according to American
Society of Echocardiography guidelines.
RESULTS
Patients with SCD had significantly higher mean±SD values for tricuspid regurgitant jet velocity than did
the controls (2.1±0.6 vs. 1.8±0.5; p<0.001). 25% of SCD patients had elevated systolic pulmonary artery
pressure (PAP) as defined by jet velocity ≥2.5 m/s(estimated systolic PAP ≥30 mm Hg) compared to 7%
of controls (P<0.001). 4% had jet velocities ≥3.0 (estimated systolic PAP≥41) compared to 0%
controls.Compared to controls, SCD patients had significantly higher values of left ventricular (LV) size;
there was no qualitative evidence of systolic dysfunction, ejection fraction (EF) ≤0.5). In fact, the
patients had significant higher values of EF and E/A ratio. Within the SCD group, there was no clear
pattern of worsening diastolic function with increased TRV. Furthermore, E/A had a significant positive
relationship with jet velocity in bivariate analysis (R=0.20; P=0.013).
CONCLUSION
Overall, this shows that prevalence of pulmonary hypertension in Nigerian patients is independent of
concomitant LV systolic or diastolic dysfunction.
African SCD patients provide a unique population for evaluation of LV dysfunction from an
epidemiological and clinical perspective. We have established that while pulmonary hypertension is
prevalent in this population the biventricular functions are preserved in contrast to patients in the USA.