Purpose: We investigated myocardial iron overload (MIO), biventricular parameters and myocardial fibrosis assessed by cardiovascular magnetic resonance (CMR) in a large cohort of thalassemia intermedia (TI) patients categorized in different transfusional regimens. This survey is particularly significant considering the debate on the opportunity to transfuse the TI patients.

Methods: We studied retrospectively 252 adult TI patients (119 females, 39±10 yrs) enrolled in the MIOT Network. MIO was assessed by a multislice multiecho T2* approach. Cine sequences were obtained to quantify biventricular function parameters. Myocardial fibrosis was evaluated by late gadolinium enhancement (LGE) acquisitions.

Results: 188 patients showed no MIO in any segment, 56 had an heterogeneous MIO (52 with a global heart T2*<20 ms), and 8 showed an homogeneous MIO.

Left ventricular (LV) and right ventricular (RV) dilatations were present in the 45% and in the 19% of cases, respectively. LV dysfunction was present in the 18.0% of the cases while RV dysfunction in the 3.63%. LV hypertrophy was found in the 8.7% of cases.

Myocardial fibrosis was found in the 22.9% of the patients and was associated with LV dysfunction (P=0.001) and hypertrophy (P=0.038).

48 patients were no transfused, 66 sporadically transfused and 138 regularly transfused. The 3 group were significantly different for the LV volume and mass indexes, the cardiac output and the myocardial fibrosis (Table).

Conclusions: Heart iron was not absent in TI and the majority of the patients showed an heterogeneous distribution. A consistent number of the TI patients had the stigmata of the high cardiac output state cardiomyopathy and myocardial fibrosis seems to be related to the high cardiac output state. The signs of the high cardiac output state were controlled in the regular transfused patients. Conversely, the regular transfusions seem to be started too late for preventing myocardial fibrosis.