Myocardial ischaemia in sickle cell anaemia: evaluation using a new scoring system

Background: Sickle cell anaemia (SCA) is associated with recurrent multi-organ ischaemia and infarction. Myocardial ischaemia (MI) and infarction are increasingly recognised as features of SCA. The prevalence and severity of MI in children with SCA is not known. Aim: To evaluate the usefulness of a new scoring system based on the standard surface electrocardiogram (ECG) in determining the prevalence and severity of MI in children with SCA. Method: MI prevalence and scores derived from standard surface ECGs of 35 children with SCA aged 3-18 years who presented consecutively during 38 episodes of vaso-occlusive crisis (VOC) were compared with those of 40 age-and sex-matched SCA patients in the steady state and 40 anaemic non-SCA patients. In SCA subjects with VOC, ECG was repeated approximately 1 week and 4-8 weeks post crisis and the respective MI scores were compared with their intra-crisis ECG and those of the two other groups. Results: Mean (SD) MI scores were significantly higher during vaso-occlusive crises [1.82 (0.20)] compared with the steady state [1.15 (0.15)] and non-SCA anaemic controls [1.13 (0.21)], p=0.017. SCA patients in crisis were 5.5 (1.20-13.99) times more likely to have MI compared with non-SCA anaemic controls (p=0.025). They were also 3.66 (1.05-12.74, p=0.042) and 7.58 (1.31-43.92, p=0.024) times more likely to have mild and significant MI, respectively. MI scores derived from the post-crisis ECGs were similar to those of steady-state SCA patients. Conclusion: ECG changes consistent with MI are common in children with SCA, especially during vaso-occlusive crises. Our proposed MI scoring system could be a useful screening tool for early detection of significant MI during crises, facilitating early institution of intervention. Further studies are needed to determine the specificity of the observed changes and to validate the proposed screening tool.