Prevalence of pulmonary hypertension in sickle cell anaemia patients of a tertiary hospital in Nigeria

Abstract

Background:Sickle cell disease (SCD) is an inherited haemoglobinopathy characterised by recurrent organ hypoxia-reperfusion cycles which may result in repeated organ damage including the lungs and heart. In SCD, pulmonary hypertension is a known complication that may precede or complicate acute chest syndrome which is often fatal. This study seeks to know the prevalence of pulmonary hypertension and its relationship with clinical and laboratory parameters in sickle cell disease patients attending a tertiary hospital in Lagos.Materials and Methods:This was a case — control study involving patients with sickle cell disease recruited from adult sickle cell clinic of Lagos State University Teaching Hospital, Ikeja and HbAA controls matched for age and sex from a tertiary educational institution in Lagos. Both the patients and controls were subjected to echocardiography and pulmonary hypertension was deduced from their cardiac tricuspid regurgitant jet velocity. Other parameters measured were age, body mass index, full blood count, red cell indices, foetal haemoglobin, chest X-ray, liver function tests, lactate dehydrogenase and pulmonary function tests. Consenting patients were 56 HbSS in steady state and 28 HbAA controls matched for age and sex. Data was analysed using SPSS version 16.0.Results:The mean age of patients was 22 ± 6 years. In two 2 of 56 (3.6%) of the participants with sickle cell disease, the pulmonary artery pressure was > 25mmHg and there was significant difference in the mean of the pulmonary artery pressure of the control and that of the patients (P-value 0.013). Also, using the appropriate correlation tests, there was significant relationship between the pulmonary artery pressure and lactate dehydrogenase, aspartate transferase and haematocrit in patients with sickle cell disease.Conclusion:Sickle cell disease is an independent cause of pulmonary artery hypertension. Variation in cardiovascular reactions to recurrent hyperhaemolysis and hyperdynamic state in sickle cell disease may explain differences in the development of cardiac complications. Exploration of these reactions may reveal other therapeutic measures to prevent complications in sickle cell disease. Clinical assessment of adult patients with sickle cell disease should include echocardiography.

Pulmonary hypertension among 5 to 18 year old children with sickle cell anaemia in Nigeria

“…[ 19 , 20 ] Two Nigerian studies which included children and adults found a wide prevalence of 3.6% to 25%. [ 17 , 18 ] The Western Nigeria study [ 18 ] with prevalence of 3.6% had a small sample size which was about one-third that of the current study and this may have accounted for the low prevalence of PHT found in their cohort. These investigators also proposed that their cohort was highly selective and better motivated for regular care compared to the Northern Nigerian participants.…”

“…In a Western Nigeria study, the authors did not report PHT in any of their controls and there was also a significant difference between the mean peak TRV of the controls and that of SCD patients. [ 18 ] This significant difference in TRV values between SCD patients and controls as well as the very low prevalence of PHT among control subjects suggests a contributory effect of the haemoglobin genotype on the degree of tricuspid regurgitation velocity.…”

“…Elevated TRV was found in 2.3% of controls in the present study population which was lower than 7% noted in a Northern Nigerian study [ 17 ] but was higher than the Lagos, Nigeria study in which none of the controls had elevated TRV. [ 18 ] The control group in the Lagos study involved only patients with genotype AA as in the current study but the Northern Nigerian study involved patients with documented haemoglobin AA as well as AS genotypes. The contributory role of the sickle cell trait in the occurrence of PHT remains to be elucidated.…”

Management of Sickle Cell Disease: A Review for Physician Education in Nigeria (Sub-Saharan Africa)

“…Pulmonary arterial hypertension is defined by end systolic pressure in the right ventricle greater than 25 mmHg (normal is less than 15 mmHg). In a cohort of Nigerian SCD patients, 2 (3.6%) out of 56 met the criteria for pulmonary hypertension [ 125 ]. Tricuspid regurgitation jet velocity of >2.5 m/sec is associated with a high risk of pulmonary hypertension and is an independent risk factor for death [ 128 ].…”

Pulmonary hypertension in Nigerian adults with sickle cell anemia

“…The prevalence of 23.9% seen in this study is comparable to the findings of another study in Zaria (Northern Nigeria) by Aliyu et al20 who made use of peak TRV of ≥2.5 m/s as a criterion and found a prevalence of 25%. Dosunmu et al21 in a study in Lagos, Nigeria, got a much lower prevalence of 3.6%. This low prevalence may be possibly due to the lower age group of the study sample compared to the present study.…”