Myocardial iron overload in thalassaemia major. How early to check?

Area of Science:

• Cardiovascular Imaging
• Pediatric Hematology
• Magnetic Resonance Imaging

Background:

• Thalassaemia major (TM) patients face risks of iron overload, particularly in the heart.
• The optimal age for initiating Cardiovascular Magnetic Resonance (CMR) T2* screening for myocardial iron overload (MIO) in TM remains unclear.
• Early detection of MIO is crucial for preventing cardiac complications in pediatric TM patients.

Purpose of the Study:

• To evaluate the prevalence of MIO, cardiac function, and fibrosis in TM patients under 10 years old using CMR.
• To determine the earliest age at which MIO can be detected in pediatric TM patients.
• To inform guidelines for the timing of cardiac T2* screening in young TM patients.

Main Methods:

• Retrospective analysis of 35 TM patients (age 4.2–9.7 years) from the Myocardial Iron Overload in Thalassaemia network.
• Cardiac iron overload assessed using CMR T2* multislice multiecho technique.
• Biventricular function evaluated via cine imaging; myocardial fibrosis detected using late gadolinium enhancement.

Main Results:

• Nine patients had no MIO, while 22 showed heterogeneous MIO (T2* ≥20 ms).
• Two patients exhibited heterogeneous MIO (T2* <20 ms), and two had homogeneous MIO.
• No myocardial fibrosis was detected in any patient. The youngest patient with T2* <20 ms was 6 years old, with no heart dysfunction and <35g iron transfused.

Conclusions:

• Cardiac iron loading can occur earlier than previously recognized in pediatric TM patients.
• The first cardiac T2* assessment should be performed as early as feasible, ideally without sedation.
• Early screening is particularly important for patients with late chelation initiation or suspected poor compliance.