Assessing cardiac and liver iron overload in chronically transfused patients with sickle cell disease

Area of Science:

• Hematology
• Cardiology
• Radiology

Background:

• Transfusional iron overload is a significant complication for sickle cell disease (SCD) patients requiring frequent red blood cell transfusions.
• While iron-induced cardiomyopathy is common in other transfused populations, it is infrequently observed in SCD.

Purpose of the Study:

• To assess myocardial and hepatic siderosis in chronically transfused SCD patients using magnetic resonance imaging (MRI).
• To evaluate the correlation between long-term serum ferritin levels, spot-ferritin, and liver iron content (LIC) measured by MRI and liver biopsy.

Main Methods:

• Thirty-two SCD patients with transfusional iron overload underwent MRI for liver and cardiac iron assessment.
• Liver iron content was also measured via liver biopsy for comparison.
• Serum ferritin (mean and spot) and echocardiogram data were collected.

Main Results:

• Serum ferritin levels (long-term mean and spot) strongly correlated with liver iron content measured by MRI-R2* and liver biopsy.
• Liver iron content by MRI-R2* showed a strong positive correlation with liver biopsy results.
• Cardiac MRI-T2* showed a modest inverse correlation with liver iron content, but moderate to severe iron overload did not correlate with impaired cardiac function on echocardiograms or biomarkers.

Conclusions:

• Sickle cell disease patients with transfusional iron overload may not exhibit significant cardiac iron loading despite elevated liver iron and ferritin levels.
• Current monitoring and management strategies for iron overload in SCD may need re-evaluation given the observed dissociation between liver and cardiac iron.
• Further research is warranted to understand the mechanisms protecting the SCD heart from iron toxicity.