Enhanced Hypercoagulability in Sickle Cell Anaemia Patients with Chronic Leg Ulcers

Abstract

Sickle Cell Anaemia (SCA) is associated with a hypercoagulable state resulting in a predisposition to venous thromboembolism. With improvements in the quality of care, more patients with SCA survive into adulthood with an associated increase in the frequency of end-organ damage and chronic complications such as chronic leg ulcers (CLUs). These ulcers rarely occur in the first decade of life and are recurrent, painful, and slow-to-heal. This study tested the hypothesis that coagulation is enhanced in SCA patients with CLU. 145 participants (50 SCA with CLU, 50 SCA without CLU, and 45 with haemoglobin AA) were assessed to determine their coagulation profile using selected tests of coagulation. The SCA with the CLU group had the lowest mean haemoglobin (Hb) concentration. SCA patients with and without CLUs had elevated mean platelet counts, shorter mean aPTT, and marginally prolonged mean PT  compared to HbAA patients. SCA with CLUs patients had a significantly shortened aPTT than those without CLUs ( $p$  = 0.035) and HbAA ( $p$  = 0.009). There were significant differences in the mean PT between SCA with CLUs patients and HbAA ( $p$  = 0.017); SCA without CLU and HbAA ( $p$  = 0.014). SCA with and without CLUs patients had higher mean D-dimer levels compared to HbAA. There was a negative correlation between Hb concentration and duration of CLU (r = -0.331, $p$  = 0.021). In conclusion, our study demonstrates a heightened hypercoagulability in SCA patients with CLUs. We did not test for platelet activation, and it is not clear what role, if any, the enhanced hypercoagulability plays in the pathogenesis of CLUs in SCA. It will be useful to ascertain if antiplatelet agents or/and anticoagulants quicken the healing of CLUs in SCA patients.