Myocardial tissue characterization and the role of chronic anemia in sickle cell cardiomyopathy

Abstract

To use cardiovascular magnetic resonance (CMR) techniques to examine possible causes for the left ventricular (LV) dilatation that occurs in sickle cell disease (SCD), including the effects of chronic anemia, iron-induced cardiomyopathy, and regional fibrosis due to sludge infarcts that occur during sickle crises. A total of 47 patients with sickle cell anemia were assessed for LV function and myocardial iron levels using CMR measurements; 30 of these were also assessed for regional fibrosis using late gadolinium-enhancement CMR. The LV function was compared to both normal controls and transfusion dependent non-iron-loaded (NIL) thalassemia major (TM) patients. Only one SCD patient had significant myocardial iron loading, and only two patients had regional fibrosis. There were significant differences in ventricular volumes of the sickle patients compared with both the normal controls and the NIL-TM population (P < 0.01). The LV changes seen in SCD are partly the result of a chronic anemia but there appears to be another contributory factor. This extra factor is not myocardial iron loading or regional fibrosis, although a homogenous fibrotic disorder affecting the left ventricle cannot be excluded.