Correlation between Changes in Cardiac Iron and Hepatic Iron in Pediatric Patients with Thalassemia Major

Introduction. A prospective magnetic resonance imaging (MRI) study demonstrated a good control of myocardial iron overload (MIO) in terms of prevention and treatment in children with thalassemia major (TM).

The aim of the present study was to evaluate if changes in MIO were related to baseline hepatic iron or changes in hepatic iron overload (HIO).

Methods. We considered 68 TM patients enrolled in the MIOT (Myocardial Iron Overload in Thalassemia) project with less than 18 years at the first MRI scan and who performed a follow-up (FU) study at 18±3 months.

Myocardial and hepatic iron burdens were quantified by the T2* technique. The value of 20 ms was used as conservative normal value for the global T2* value. Liver T2* values were converted into liver iron concentration (LIC) values. A LIC<3 mg/g/dw indicated significant no HIO, between 3 and 7 mg/g/dw mild HIO, between 7 and 15 mg/g/dw moderate HIO, and ≥15 mg/g/dw severe HIO.

Results. Thirty-six patients were females and mean age at the time of the baseline MRI was 13.74±3.09 years. Baseline global heart T2* values were 29.72±11.21 ms and 16 (23.5%) patients showed significant baseline MIO.

The percentage changes in global heart T2* values per month in the whole patient population were 0.66±1.70 and they resulted significantly higher in the 16 patients with significant baseline MIO versus the patients with no baseline MIO (1.99±2.53% vs 0.25±1.09% ms; P=0.002).

Percentage changes in global heart T2* values per month were not influenced by initial MRI LIC values (R=0.048; P=0.695) (Figure 1A) and were comparable among the 4 groups of patients identified on the basis of baseline MRI LIC values (14 no HIO: 0.29±1.12% vs 21 mild HIO: 0.75±1.56% vs 15 moderate HIO: 0.82±2.03% vs 18 severe HIO: 0.71±2.00%; P=0.876).

Percentage changes in global heart T2* values per month were not associated to final MRI LIC values (R=-0.134; P=0.277) (Figure 1B).

The correlation between % changes in global heart T2* and MRI LIC values did not reach the statistical significance (R=-0.244; P=0.067) (Figure 1C).

In patients with baseline MIO no correlation was found between % changes in global heart T2* values per month and initial MRI LIC values (R=-0.325; P=0.219) or % changes in MRI LIC values per month (R=-0.353; P=0.180).

Conclusion. In pediatric TM patients changes in cardiac iron are not correlated to baseline MRI LIC values and changes in hepatic iron. So, our data seem not supporting the hypothesis for which it is necessary to clean the liver before removing iron from the heart.

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