Cardiac Disease in Egyptian Thalassemia Major and Sickle Cell Disease Adolescents in relation to Vitamin D Status Using Echocardiogram & Ultrafast Magnetic Resonance Imaging

Abstract

Abstract Background Cardiovascular complications are well recognized in patients with β-thalassemia major (β-TM) and sickle cell disease (SCD). Vitamin D deficiency is prevalent in patients with transfusion-dependent thalassemia and there is an association between vitamin D deficiency and both left ventricular function and iron overload in thalassemia. However, the relationship between vitamin D and cardiac iron is not well studied in Egypt and the role of vitamin D in cardiac disease in SCD and β-TM needs to be assessed. Aim To assess vitamin D status in children and adolescents with SCD and β-TM in relation to cardiac complications using echocardiography and cardiac magnetic resonance (CMR) T2*. Methods Forty-one patients with SCD and 35 patients with β-TM without symptomatic cardiac disease were studied stressing on history of splenectomy and transfusion history. Markers of hemolysis, serum ferritin and vitamin D levels were measured. Liver iron concentration (LIC) was assessed by magnetic resonance imaging (MRI). Screening for cardiovascular abnormalities was performed by the non-invasive Doppler echocardiography and CMR was used to assess myocardial iron overload. Results Echocardiography showed that cardiac functions were significantly impaired in β-TM patients compared with SCD while the frequency of pulmonary hypertension risk (elevated TRV ≥2.5 m/sec) was consistent between both β-TM and SCD groups. Cardiac T2* (which reflects cardiac iron overload) was significantly lower while myocardial iron concentration (MIC) was significantly higher in β -TM patients compared with SCD group. Vitamin D levels were decreased in both SCD and β-TM patients than control levels; however, SCD patients had significantly lower vitamin D levels. Low vitamin D levels were significantly associated withincreased risk of pulmonary hypertension in the SCD group while In β-TM group, vitamin D levels were significantly lower in patients with cardiac disease and those with serum ferritin levels ≥ 2500 µg/L. A significant evidence of diastolic dysfunction was found in SCD and β-TM patients who had low serum vitamin D level < 20 ng/mL. Vitamin D levels were negatively correlated to serum ferritin and LIC while positively correlated to cardiac T2*. Conclusion Low vitamin D levels were associated with cardiopulmonary dysfunction in adolescents with SCD and β-TM. Vitamin D deficiency in those patients was linked to cardiac iron overload leading to iron induced cardiomyopathy. Proper chelation therapy is mandatory to improve cardiac disease, iron overload and consequently, vitamin D status in β-TM patients.