Introduction

Sickle-thalassemia results from the combined heterozygosity for sickle-cell and β-thalassemia genes. This study evaluates myocardial and hepatic iron overload and cardiac function in Italian patients and explores their correlation with transfusions, age and sex.

Methods

Fifty-nine sickle-thalassemia patients (29 males, mean age 35.6±14.1 years), enrolled in the MIOT network underwent magnetic resonance imaging (MRI). T2* value for all 16 myocardial segments and global heart T2* value were calculated. Hepatic T2* value was converted into liver iron concentration (LIC). Cine images were acquired to quantify biventricular volumes and ejection fraction (EF).

Results

55 (93%) patients had all segmental T2* values normal (>20 ms). Of the 4 patients with abnormal segmental T2* values, all showed an heterogeneous myocardial iron overload (some segments with T2*>20 ms and other with T2*<20 ms) and only one had a global T2*<20 ms. The mean global heart T2* value was 34.4±6.2 ms. The mean LIC was 5.9±6.5 mg/g/dw and 30 patients (50.8%) had a pathological value (≥ 3 mg/g dw). There was a statistically significant positive correlation between global heart T2* and age but with poor linearity (R=0.368; P=0.004) and there was not a significant correlation between age and LIC.

Males and females had comparable global heart T2* values and LIC values.

Twenty patients were regularly transfused, 32 received sporadic transfusions while 7 were not transfused. The comparison among the three groups is shown in Table 1. We did not find significant differences in the global heart T2* value while patients regularly transfused had significantly higher LIC than sporadically transfused patients. Biventricular volumes indexed by body surface area and ejection fractions were comparable among the groups.

Table 1
TransfusionsP
No (N=7)Sporadic (N=32)Regular (N=20)
Global heart T2* (ms) 33.4±7.3 32.4±6.3 35.5±5.4 0.425 
Pts with global heart T2*<20 ms, N (%) 0 (0) 0 (0) 1 (5.0) 0.458 
MRI LIC (mg/g dw) 3.6±3.3 3.6±2.9 10.5±8.9 0.001 
Pts with MRI LIC ≥ 3 mg/g/dw , N (%) 3 (42.9) 11 (34.4) 16 (80.0) 0.004 
Left ventricular end-diastolic volume index (ml/m2) 93.3±40.6 93.8±23.8 90.4±15.9 0.910 
Left ventricular end-systolic volume index (ml/m2) 40.2±30.9 39.8±17.2 33.5±7.7 0.365 
Left ventricular mass index (g/m2) 66.5±12.5 61.7±14.8 61.2±22.6 0.709 
Left ventricular ejection fraction (%) 66.6±7.1 59.9±7.9 62.3±7.7 0.168 
Right ventricular end-diastolic volume index (ml/m2) 81.9±45.0 85.9±23.7 83.5±13.9 0.916 
Right ventricular end-systolic volume index (ml/m2) 36.2±13.1 34.9±14.7 29.4±7.7 0.249 
Right ventricular ejection fraction (%) 47.8±19.8 52.1±16.5 53.8±12.1 0.342 
TransfusionsP
No (N=7)Sporadic (N=32)Regular (N=20)
Global heart T2* (ms) 33.4±7.3 32.4±6.3 35.5±5.4 0.425 
Pts with global heart T2*<20 ms, N (%) 0 (0) 0 (0) 1 (5.0) 0.458 
MRI LIC (mg/g dw) 3.6±3.3 3.6±2.9 10.5±8.9 0.001 
Pts with MRI LIC ≥ 3 mg/g/dw , N (%) 3 (42.9) 11 (34.4) 16 (80.0) 0.004 
Left ventricular end-diastolic volume index (ml/m2) 93.3±40.6 93.8±23.8 90.4±15.9 0.910 
Left ventricular end-systolic volume index (ml/m2) 40.2±30.9 39.8±17.2 33.5±7.7 0.365 
Left ventricular mass index (g/m2) 66.5±12.5 61.7±14.8 61.2±22.6 0.709 
Left ventricular ejection fraction (%) 66.6±7.1 59.9±7.9 62.3±7.7 0.168 
Right ventricular end-diastolic volume index (ml/m2) 81.9±45.0 85.9±23.7 83.5±13.9 0.916 
Right ventricular end-systolic volume index (ml/m2) 36.2±13.1 34.9±14.7 29.4±7.7 0.249 
Right ventricular ejection fraction (%) 47.8±19.8 52.1±16.5 53.8±12.1 0.342 
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Conclusions

In respect of MIO, the sickle/thalassemia patients are similar to patients with homozygous SCD for which iron overloading is relatively rare. Hepatic iron overload may develop also in no regularly-transfused patients, maybe due to increased absorption of iron from the digestive tract, characteristic of both SCD and thalassemia intermedia patients. This finding underlines the importance to monitor by MRI also no regularly transfused sickle/thalassemia patients.

Disclosures:

No relevant conflicts of interest to declare.

Topics:
cardiac function, hemoglobin sickle thalassemia, iron overload, myocardium, magnetic resonance imaging, blood transfusion, iron, brachial plexus neuritis, thalassemia, thalassemia intermedia

Author notes

*

Asterisk with author names denotes non-ASH members.

© 2013 by The American Society of Hematology
2013
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