The efficacy of tissue Doppler imaging in predicting myocardial iron load in patients with beta-thalassemia major: correlation with T2* cardiovascular magnetic resonance

Abstract

Tissue Doppler imaging (TDI) can detect myocardial dysfunction related to iron load in patients with beta-thalassemia major (TM). We aimed to assess the efficacy of pulsed-wave TDI (PW-TDI) in predicting myocardial iron load in patients with TM using T2* magnetic resonance (MR) as the gold-standard non-invasive diagnostic test. 33 asymptomatic TM patients, mean aged 18 +/- 6 years (6-31) with normal left ventricular (LV) global systolic function were evaluated by conventional echocardiography and PW-TDI. Results were compared with 20 age and sex-matched controls. TDI measures included myocardial systolic (Sm), early (Em) and late (Am) diastolic velocities at basal and middle segments of septal and lateral LV wall. Myocardial iron deposition were measured in 29/33 patients by T2* MR. TM patients were also subgrouped according to those with iron load (T2* <or= 20 ms) and those without (T2* > 20 ms). Mean T2* was 12.3 +/- 7.8 ms (4-31.3). Abnormal myocardial iron load (T2* < 20 ms) was found in 25/29 (86%) patients. The following TDI measures were lower in patients than in controls: basal septal Em (P < 0.001) and Am (P < 0.05), mid-septal Am (P < 0.05), mid-lateral LV wall Sm (P < 0.05) and Am (P < 0.05). Regional myocardial dysfunction were more prominent in patients with T2* <or= 20 ms. Mid-septal Sm and Em significantly correlated with mid-septal T2*(r = 0.44, P = 0.023 and r = 0.54, P = 0.004, respectively). The PW-TDI parameters and the cut-off values for predicting presence of myocardial iron load were determined. PW-TDI technique was found both sensitive and specific in predicting presence of myocardial iron load in TM patients with normal LV global systolic function. Therefore, it can be used for screening of TM patients.

The relationship between myocardial t2* and left ventricular volumetric and functional parameters in thalassemia major patients

“…In those studies, a significant increase in the LV diameters (LV end-diastolic diameter and LV end-systolic diameter) was detected in thalassemia patients relative to the normal control group (26,27). Our findings are in accordance with these studies.…”

“…We detected an inverse correlation between the myocardial T2* value and both LVESVi and LVEDVi. The increase in the left ventricular volume or diameter in these patients is mainly attributed to the high cardiac output state secondary to chronic anemia (26). The increase in the left ventricular end-systolic volume has been previously considered a precursor of subclinical left ventricular dysfunction (28).…”

Iron overload in polytransfused patients without heart failure is associated with subclinical alterations of systolic left ventricular function using cardiovascular magnetic resonance tagging

“…Also in the literature, reports on diastolic dysfunction in patients with iron overload are conflicting. Indeed some studies using echocardiography [21,22,24,31,32], reported alterations of E/A ratio and E/e'ratios in multiple transfused patients when iron overload by T2* was present. On the other hand, Leonardi et al [16] reported, similar to our findings, poor correlation between various diastolic parameters by echocardiography and T2* measurement by CMR in patients with iron overload.…”

The relation of color m-mode flow propagation with cardiac iron load in patients with thalassemia major

“…Although some of these studies have demonstrated a significant correlation (25)(26)(27), others have not (11,28). The main limitation of TDI parameters is their dependence on heart rate.…”