Global Myocardial Wall Thickness in Transfusion-Dependent Thalassemia: A Cross-Sectional MRI Analysis

<b>Background:</b> This retrospective cross-sectional study evaluated the association of the global wall thickness index (GTI), derived from cardiovascular magnetic resonance (CMR), with demographic, clinical, and imaging findings, as well as heart failure history in transfusion-dependent thalassemia (TDT) patients. <b>Methods:</b> We analyzed 1154 TDT patients (52.9% female, 37.46 ± 10.67 years) from the Extension-Myocardial Iron Overload in Thalassemia project and 167 healthy controls (54.5% female, 36.33 ± 15.78 years). The CMR protocol included the T2* technique for the assessment of iron overload, cine imaging for the assessment of left ventricular (LV) function and size, and late gadolinium enhancement (LGE) imaging for the detection of replacement myocardial fibrosis (in the subset of 366 patients who underwent contrast administration). GTI (in mm/m²) was calculated from LV mass and end-diastolic volume. <b>Results:</b> GTI discriminated TDT patients from controls better than the LV end-diastolic volume index. Among TDT patients, GTI was higher in males, in those with diabetes, and in those with severe myocardial iron overload (cardiac T2* < 10 ms), but was unrelated to age, hemoglobin and ferritin levels, splenectomy, hepatic and pancreatic T2* values, LV ejection fraction, and fibrosis. GTI showed a diagnostic performance comparable to global heart T2* and superior to LV ejection fraction in identifying patients with prior heart failure. <b>Conclusions:</b> GTI is elevated in TDT patients compared with healthy controls. Male sex and severe myocardial iron overload are key determinants of GTI in TDT. Increased GTI is linked to a history of heart failure, supporting its role as a complementary tool to conventional CMR indices.