Tissue Doppler imaging and NT-proBNP levels show the early impairment of ventricular function in patients with ß-thalassaemia major

Abstract

ß-thalassaemia major is a chronic haemolytic anaemia, and congestive heart failure (CHF) is the most common cause of death in this disease. N terminal pro B type natriuretic peptide (NT-proBNP) increases with the severity of CHF and predicts the prognosis. The aim of this study was to investigate the relation between left ventricular systolic and diastolic function determined by standard pulsed wave Doppler (PWD), tissue Doppler imaging (TDI) and NT-proBNP in patients with ß-thalassaemia major.

Thirty-four patients with ß-thalassaemia major and 34 healthy individuals were included in the study. Blood samples were taken for NT-proBNP. All patients and controls underwent echocardiographic examination.

All cardiac chambers were significantly increased in the patient group. Left and right ventricular (LV, RV) ejection fractions and all diastolic parameters were normal in the patients and controls.Tissue Doppler imaging (TDI) showed a significant decrease in LV and RV S_m velocities in patients compared to the controls. NT-proBNP levels were also significantly higher in the patient group. There was a negative correlation between serum NT-proBNP levels and LV S_m and RV S_m velocities in patients (r=-0.426, P=0.006 and r=-0.409, P=0.009, respectively). Linear regression analysis showed that LV S_m and RV S_m were independent predictors for NT-proBNP.

Our findings suggest that although iron overload in patients with ß-thalassaemia major impairs the systolic and diastolic functions of both ventricles, it impairs the systolic function earlier than diastolic function. Tissue Doppler imaging is an easy and reliable method in the early determination of ventricular dysfunction in these patients.

Key Words:

• tissue Doppler imaging
• ß-thalassaemia major
• NT-proBNP