Assessment of Some Haemostatic Parameters in Sickle Cell Anaemia Subjects Resident in Rivers and Bayelsa States

Aim: The aim of this study was to assess some haemostatic parameters in sickle cell anaemia subjects in Rivers and Bayelsa States.

Study Design: This study is a cross-sectional observational study.

Place and Duration of Study: This study was carried out at the University of Port Harcourt Teaching Hospital, Rivers State, and the Federal Medical Centre, Yenagoa, Bayelsa State, between the months of February and August, 2020.

Methodology: A total of four hundred and fifty (450) subjects with age range of 1-50 years were randomly selected. There were about 200 registered patients (adults and children alike) at the sickle cell clinics of the University of Port Harcourt Teaching Hospital, and the Federal Medical Centre, Yenagoa, with an average of 4 new patients per month. The sample size was obtained using a prevalence of sickle cell anaemia of 2% and the sample size was calculated using Cochran sample size formula. Five milliliters (5ml) of venous blood sample was withdrawn from the peripheral vein in the upper limb of subjects using a standard venipuncture technique. The sample was rocked gently to mix and kept at room temperature and the haemostatic parameters (vWF, FVIII, D-dimer, L-arginine, fibrinogen, ADAMTS13) were assayed quantitatively with Bioassay Technozym kit using Microplate Reader (Labtech microplate auto ELISA plate reader, an IS0 13485:2003 CE and WHO compliance Co., Ltd. Shanghai International Holding Corp. GmbH; Europe) calibrated to a wavelength of 450 nm with strict adherence to the manufacturer's instructions, while PT and APTT were analysed with Fortress reagent and Uniscope SM801A Laboratory using water bath.Data management and statistical analyses were conducted using Statistical Analyses System SAS 9.4 (SAS Institute, Cary, North Carolina, USA) and p values less than .05were considered statistically significant.

Results: The results showed the mean comparison of haemostatic parameters in sickle cell anaemia and control subjects. The comparison of haemostatic parameters showed significant(p<.05) increasesand decreases inVaso-Occlusive Crisis (VOC) and steady state respectively compared with the control group. There was statistically significantreduction in the mean comparison of L-Arginine (p<.01) in VOC) condition than steady state in relation to the control group in our study population, while D-Dimer, ADAMTS13 were also significantly reduced statistically (p<.01) in VOC condition than steady state compared with the control group. However, the mean FVIII inhibitor, Fibrinogen, PT (INR) and APTT were significantly higher (p<.01) in VOC than steady state when compared to controls with normal haemoglobin (HbAA).Correlations of haemostaticparameters by sickle cell anaemia subjects’ condition showed more significant positive correlations in VOC than steady state.

Conclusion: This study showed a heightened hypercoagulability in Sickle Cell Snaemia(SCA)subjects, and further pave way for better understanding particularly the diagnostic variables underlying SCA, specific to each subject condition (steady state and VOC). Subjects with SCA, particularly during VOC, undergo significant haemostatic alterations that increase their risk of developing coagulation activation-related complications. Thus, though selected markers of coagulation were significantly different between the subject conditions, they were often significantly higher in the SCA.