A reduction of left ventricular global longitudinal strain (LV GLS) assessed with speckle tracking echocardiography (STE) predicts myocardial fibrosis in transfusion dependent beta-thalassemia

Abstract

Funding Acknowledgements Type of funding sources: None. Background Cardiac involvement is common and the leading cause of death in transfusion dependent beta-thalassemia (TDT) patients. It is mainly related with cardiac iron overload and myocardial fibrosis, leading to a progressive cardiac damage which evolves towards a severe deterioration of systo-diastolic cardiac function. Moreover, myocardial fibrosis may not be directly related with the degree of cardiac iron deposition and it is associated with a high risk of cardiovascular complications. To date, Cardiac Magnetic Resonance (CMR) is the gold standard for the evaluation of iron overload with T2* sequences and for the detection of myocardial fibrosis with late gadolinium enhancement (LGE). However, CMR is not always feasible. Left Ventricular Global Longitudinal Strain (LV GLS) with Speckle Tracking Echocardiography (STE) is a non-invasive imaging tool, which may play a key role in the early recognition of subclinical myocardial damage and dysfunction (figure 1). This may help clinicians in guiding the diagnostic algorithm and the therapeutic approach. Purpose The aim of this study was the evaluation of the role of LV GLS with STE in the characterization of myocardial involvement in a population of TDT patients. Methods An observational, cross-sectional, monocentric study was conducted by the enrollment of 38 patients with TDT from the outpatient clinic of hematology of our hospital. Each patient underwent a thorough clinical evaluation including laboratory testing, transthoracic echocardiogram (TTE) with LV GLS-STE and contrast enhanced CMR with T2* technique and LGE sequences. A T2* value < 20 msec was set to define the presence of iron overload. Results The mean age of patients was 38 ± 10 years with a slight prevalence of female sex (53% vs 47% respectively). Cardiovascular risk factors were rarely present, the most common was arterial hypertension in about 12% of patients. The TTE pointed out a left ventricular ejection fraction within the normal range (mean value of 59 ± 5%). As regards LV GLS, the mean value was −19,8 ± 2,9%. Cardiac iron overload was observed in 18% of patients, while about 15% of patients had cardiac fibrosis. A mild clinical but not statistically significant difference was observed between LV GLS values in patients with cardiac iron overload as compared to patients without (−18,3 ± 2,3% vs −20,1 ± 3,0%; p value=0,147). A statistically significant difference was documented between LV GLS values in patient with cardiac fibrosis as compared to patient without LGE (−16.4 ± 1.7% vs −19,8 ± 2,4%; p value=0,004). A LV GLS cut-off value of −18,3% was found by the analysis of ROC curve with an AUC of 0,904 (95% CI: 0,798–1,000) (figure 2). Conclusions In a small population of TDT patients we observed that LV GLS with STE may be a promising tool in the early identification of cardiac damage to provide useful informations for diagnostic and therapeutic approach.