Συσχέτιση και συνεκτίμηση US δεικτών καρδιακής λειτουργίας με MRI μετρήσεις εναπόθεσης σιδήρου στην καρδιά ασθενών με μεσογειακή αναιμία ; Correlation and co-estimation of US indices of cardiac function with MRI measurements of iron deposition in the heart of patients with thalassemia

Background and objectives: Despite advances in survival in patients with thalassemia major (TM) the most common cause of death is cardiac disease. Regular cardiac follow-up is imperative in order to identify and reverse pathology. Cardiac Magnetic Resonance (CMR) and Echocardiography (US) are applied in parallel to TM patients for cardiac evaluation and ongoing monitoring. Moreover cardiac iron load can be indirectly quantified by CMR’s T2*. However CMR accessibility is limited, whereas US is relatively inexpensive and readily available. The objectives were to find US parameters that may be useful for predicting cardiac iron and to assess the accuracy and reliability of the two methods, with a particular focus on routine US application. Design and methods: We correlated a number of parameters derived from US to CMR’s T2* score in 142 TM patients and compared common volumetric measurements between the two techniques Results: All patients with decreased left ventricular (LV) shortening fraction (LVSF ? 30%) had cardiac iron overload (T2* ? 15 ms). After removing these patients from the analysis, the total diameter index (Tdi) >5.57 cm/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%, 20.5% 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 severe load from those with none to moderate cardiac iron load, with specificity of 91%, 98.5%, and 98.5%, respectively, but again with low sensitivity. In addition while comparing the common volumetric parameters between CMR and US (Teichholz's M-mode formula) we found that the correlation for the ejection fraction (EF) was acceptable (r=0.60) without a statistically significant difference (p=0.37) and the Bland & Altman plot range was narrow (25.8%) Interpretation and conclusions: US parameters for cardiac iron overload ...