Cardiac iron overload in sickle-cell disease

Area of Science:

• Hematology
• Cardiology
• Radiology

Background:

• Sickle cell disease (SCD) patients on chronic transfusions have lower myocardial iron overload (MIO) risk than thalassemia major (TM) patients, but cardioprotection is incomplete.
• Identifying risk factors for MIO in SCD is crucial for preventing cardiac complications.

Purpose of the Study:

• To present the clinical characteristics of SCD patients who developed MIO and identify potential risk factors for cardiac iron accumulation.

Main Methods:

• Cardiac, hepatic, and pancreatic iron overload were assessed using R2 and R2* magnetic resonance imaging (MRI) in 201 chronically transfused SCD patients.
• Clinical data, including transfusion history, chelation compliance, and laboratory markers, were analyzed for patients who developed MIO.

Main Results:

• Six SCD patients prospectively developed MIO, with most on chronic transfusion >11 years and poor chelation compliance (<50%).
• MIO onset correlated with reticulocyte and hemoglobin S percentages, serum ferritin >4600 ng/ml, and liver iron concentration >22 mg/g.
• Pancreatic R2* >100 Hz was observed in 5/6 patients with MIO, showing a proportional rise in cardiac iron. A higher liver iron threshold for MIO was noted compared to TM patients.

Conclusions:

• MIO occurs in a small subset of chronically transfused SCD patients, primarily associated with exceptionally poor iron control and prolonged transfusion duration.
• Factors like effective erythropoiesis may contribute to cardiac risk. Pancreas R2* MRI is a valuable screening tool for cardiac iron in SCD.