Background and objective: Heart iron load (cardiac Fe) can be indirectly quantified by cardiac magnetic resonance (CMR) T2*. CMR accessibility is limited, whereas echocardiography (Echo) is relatively inexpensive and readily available. The objective was to find Echo parameters that may be useful for predicting cardiac Fe.
Design and methods: We compared a number of parameters derived from Echo to cardiac Fe in 142 thalassaemia major patients who had undergone a CMR study.
Results: All patients with decreased left ventricular (LV) function had cardiac Fe. After removing those patients from the analysis, the total diameter index (Tdi) >5.57 cms/m2, left atrial diameter index >2.41 cm/m2, and the diastolic parameter E/A > 1.96 were highly specific (91.4%, 97.1% and 96.9% respectively) but had low sensitivity (31.8%, 20.45% and 21.8%) in predicting iron load. A right ventricular index >1.47 cm/m2, LV systolic index >2.26 cm/m2 or Tdi >6.26 cm/m2 discriminated between patients with no, or mild to moderate cardiac Fe from those with heavy load, with specificity of 91%, 98.5%, and 98.5%, respectively, but with low sensitivity.
Interpretation and conclusions: Echo parameters for cardiac Fe prediction have restricted value, whereas CMR is essential to assess cardiac Fe. However, patients with decreased LV systolic function should be considered a priori as having cardiac Fe, and chelation therapy should be intensified. This also applies to patients who have the above-described Echo criterion values, even if CMR is not available. Once a patient is found by CMR to have cardiac Fe, then the above Echo criterion values may be useful for ongoing monitoring.