A STUDY OF D-DIMER AND SOME FIBRINOLYTIC PROTEINS IN PATIENTS WITH SICKLE CELL ANAEMIA IN STEADY STATE AND IN VASO OCCLUSIVE CRISIS AT LAGOS UNIVERSITY TEACHING HOSPITAL (LUTH)

Abstract

AIMS/BACKGROUND OF STUDY
Sickle cell anaemia has been described as a hypercoagulable state. A number of
coagulation abnormalities as well as abnormalities in fibrinolysis have been described in
this disorder.
However, whether the activation of blood coagulation and fibrinolysis is contributory to
vaso-occlusive crisis is unknown and therefore the predictive value of these coagulant
and fibrinolytic proteins in determining the onset of vaso-occlusive crisis has not been
documented.

This study therefore aims to determine the plasma concentration of some fibrinolytic
proteins (D-dimer, Plaminogen, Tissue Plasminogen Activator) and coagulant
proteins;(Fibrinogen and Fibrinopeptide A) in sickle cell anaemia patients in both steady
state and in vaso-occlusive crisis for the purpose of determining their clinical value in
assessing and/or predicting the onset of vaso-occlusive.

Study Design: This is a two –arm cross-sectional descriptive study conducted on sickle
cell anaemia patients in steady states (Arm 1) and in vaso-occlusive crises (Arm 2)
attending the Adult and Paediatrics Haematology Out-Patient Clinics as well as the
Emergency Unit of Lagos University Teaching Hospital.

Materials and Methods: Eighty (80) subjects who satisfied the inclusion criteria were
recruited into the study. Of these, 25 were sickle cell anaemia subjects in steady state
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(Arm 1), 25 in Vaso-occlusive crises (Arm 2) and the rest (30) were HbAA controls.
Plasma D-dimer, plasminogen, tissue plasminogen activator, fibrinogen and
fibrinopeptide A were determined on EDTA samples of all subjects using ELISA test
kits.
Full blood counts, Red cell indices and prothrombin time and Activated partial
thromboplastin time test were also determined.

Result: There was no significant difference in plasma D-dimer concentration between
subjects in VOC (45.92 ± 37.29ng/ml) and steady state (51.72 ± 34.12ng/ml) P = 0.589.
No significant difference was also observed in the Mean D-dimer concentration between
controls (37.25 ± 34.85ng/ml) and subject in VOC and steady state P = 0.425 and 0.175
respectively.
Similar findings were observed for plasma plasminogen, Tissue plasminogen activator
and fibrinogen.

However, there was a significant difference in plasma FPA concentration between sickle
cell anaemia subjects in steady state (449.67 ± 310.01ng/ml) compared with HbAA
controls (163.52 ± 86.26ng/ml), P = 0.001.

Also, a significant difference was observed between subjects in VOC (680.99 ±
411.37ng/ml) compared with Hb AA controls. P= 008.
In addition, with established 95% confidence interval of FPA in HbSS in VOC (503.09
858.87ng/ml) the sensitivity and specificity of this assay (FPA) greater than 503ng/ml as
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a predictor of VOC was 68.4% and 65% respectively. The PPI and NPI were 56.5% and
76% respectively.

Prothrombin time test was significantly prolonged in steady state subjects (17.74 ± 1.31s)
compared with controls (16.46 ± 0.95s) P = 0.000. The prolongation of PT observed in
steady state did not occur in VOC. There was no significant difference between PT in
controls and VOC (16.31 ± 0.81), P = 0.591. The APPT was significantly prolonged in
both steady state (47.76 ± 4.80s) and VOC subjects (52.24 ± 5.34s) compared with
controls (37.75 ± 1.41s). P = 0.000 in every case.

Conclusion: Fibrinolysis is not significantly increased in sickle cell anaemia either in the
steady state or during VOC.
Fibrinopeptide A assay appears to be of value in the assessment of VOC in sickle cell
anaemia.