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

<jats:title>Summary</jats:title><jats:p>The age at which it is necessary to start Cardiovascular Magnetic Resonance (<jats:styled-content style="fixed-case">CMR</jats:styled-content>) T2* screening in thalassaemia major (<jats:styled-content style="fixed-case">TM</jats:styled-content>) is still uncertain. To clarify this point, we evaluated the prevalence of myocardial iron overload (<jats:styled-content style="fixed-case">MIO</jats:styled-content>), function and fibrosis by <jats:styled-content style="fixed-case">CMR</jats:styled-content> in <jats:styled-content style="fixed-case">TM</jats:styled-content> patients younger than 10 years. We retrospectively selected 35 <jats:styled-content style="fixed-case">TM</jats:styled-content> patients enrolled in the Myocardial Iron Overload in Thalassaemia network. <jats:styled-content style="fixed-case">MIO</jats:styled-content> was measured by T2* multislice multiecho technique. Biventricular function parameters were evaluated by cine images. To detect myocardial fibrosis, late gadolinium enhancement images were acquired. Patients’ age ranged from 4·2 to 9·7 years. All scans were performed without sedation. Nine patients showed no <jats:styled-content style="fixed-case">MIO</jats:styled-content>, 22 patients had heterogeneous <jats:styled-content style="fixed-case">MIO</jats:styled-content> with a T2* global value ≥20 ms; two patients had heterogeneous <jats:styled-content style="fixed-case">MIO</jats:styled-content> with a T2* global value &lt;20 ms and two patients showed homogeneous <jats:styled-content style="fixed-case">MIO</jats:styled-content>. No patient showed myocardial fibrosis. Among the patients with heart T2*&lt;20 ms, the youngest was 6 years old, none showed heart dysfunction and the iron transfused was &lt;35 g in all cases. Cardiac iron loading can occur much earlier than previously described. The first cardiac T2* assessment should be performed as early as feasible without sedation, especially if chelation is started late or if poor compliance is suspected.</jats:p>

section_content: It is still controversy in thalassemia major (TM) if Cardiovascular Magnetic Resonance (CMR) T2* screening should be initiated before the 10 years. To answer this question, we studied retrospectively the prevalence of cardiac iron and function and myocardial fibrosis by CMR in a consistent cohort of TM patients younger than 10 years.
section_name: Background

section_content: From the 2171 patients enrolled in the MIOT (Myocardial Iron Overload in Thalassemia) network, we retrospectively selected the 35 TM patients aged less than 10 years who had undergone at least one MRI scan. Myocardial iron overload (MIO) was measured by T2* multislice multiecho technique. Biventricular function parameters were quantitatively evaluated in a standard way by cine images. To detect myocardial fibrosis, late gadolinium enhancement images were acquired.
section_name: Methods

section_content: Patients' age ranged from 4. 2 to 9. 7 years. All MRI scans were performed without sedation. Nine patients (25. 7%) showed no myocardial iron overload (MIO), 22 patients (62. 9%) showed an heterogeneous MIO with a T2* global value ≥ 20 ms; 2 patients (5. 7%) showed an heterogeneous MIO and a T2* global value < 20 ms and 2 patients (5. 7%) had a homogeneous MIO (Figure 1 ). Biventricular function parameters were assessed only in 28/35 patients (80%), because for 7 patients a short MRI protocol was chosen to avoid sedation. LV dysfunction (EF < 54%) was found in one patient (male, 7-year old, treated with deferoxamine and showing an heterogeneous myocardial iron overload with a global T2* value = 31. 1 ms). No patient showed RV dysfunction. Finally, 14 patients completed the MRI protocol with acquisition of the LGE images and none of them showed myocardial fibrosis. Table 1 reports the data of the 4 patients (3 males and 1 female) with significant myocardial iron overload (global heart T2* < 20 ms). The youngest patient was 6 years old, all patient showed no heart dysfunction and in all the iron transfused was less than 35 g.
section_name: Results

section_content: The first cardiac T2* assessment should be performed as early as possible without sedation and it is mandatory whenever poor compliance is suspected or if chelation has been started late.
section_name: Conclusions

section_content: The MIOT project receives "no-profit support" from industrial sponsorships (Chiesi Farmaceutici S. p. A. and ApoPharma Inc. ). This study was also supported by: "Ministero della Salute, fondi ex art. 12 D. Lgs. 502/92 e s. m. i., ricerca sanitaria finalizzata anno 2006" and "Fondazione L. Giambrone".
section_name: Funding

section_name: Authors' details