Results:
Distribution of gender and age were similar in both groups (p>0.05). Ferritin levels were significantly high in the study group (p<0.001). Conventional echocardiographic and pulsed-wave Doppler studies were similar between the two groups (Table I). Systolic and diastolic functions in TD were found significantly more impaired in thalassemia patients compared to the healthy subjects (Table II).
The mean serum ferritin level in the study group was found 2242.3±2174.2 (109-9843) ng/ml. Neither with TD nor T2*MRI measurements were correlated with serum ferritin levels in thalassemia patient.
The mean T2*MRI score was 187.±7.7 (7.3-29.8) ms in the study group. The patients were stratified into two subgroups according to iron load; Group 1: those with iron overload (T2*MRI<20ms) and group 2: those without iron overload (T2*MRI ≥20ms). There were twenty-one (63.6%; 21/33) and twelve (36.4%;12/33) patients in groups 1, and 2, respectively. Serum ferritin levels were similar in both subgroups. Of the TD measurements, only MPI-septal measurement was significantly worsened in myocardial iron overload group (MPI-septal; 0.47±0.09 in group 1 versus 0.38±0.07 in group 2, p<0.01). There was negative correlation between MPI-septal and T2*MRI measurements (r:-0.343, p=0.05, Figure 2). The cut-off level of MPI septal in showing iron overload was found 0.37 ms of which the sensitivity and specificity were found 58.3% and 90.48%, in respectively. The decrease in T2*MRI scores in iron overload group caused longer duration in ET-septal values measured by TD (r:-0.507, p=0,019).
Tissue Doppler measurements in thalassemia patients with no myocardial iron overload were separately compared with the controls. Of the velocity measurements (Am,Em,Sm); only Sm velocity obtained from the left ventricular wall was found significantly different (Sm-LV 10.2±1.5cm/ms in thalassemia patients versus 12.4±1.9 cm/ms in the controls, p<0.005, data not shown). Although the time intervals and MPI on the measured interventricular septum were found normal, they were significantly impaired on the lateral wall of left and right ventricles (Table III). Of the septal measurements, only IVA-septal was found more impaired in non-iron overloaded thalassemia patients (p<0.05, Table III).