THE DIAGNOSTIC VALUE OF PULSED WAVE TISSUE DOPPLER IMAGING IN ASYMPTOMATIC BETA- THALASSEMIA MAJOR CHILDREN AND YOUNG ADULTS ; RELATION TO CHEMICAL BIOMARKERS OF LEFT VENTRICULAR FUNCTION AND IRON OVERLOAD .

摘要

Background : Cardiac iron toxicity is the leading cause of death among β-halassaemia major (TM) patients. Once heart failure becomes overt , it will be difficult to reverse . Objectives : To investigate non overt cardiac dysfunctions in TM patients using pulsed wave Tissue Doppler Imaging (TD I) and its relation to the iron overload and brain natruritic peptide (BNP). Methods : Thorough clinical , conventional echo and pulsed wave TDI parameters were compared between asymtomatic 25 β-TM patients and 20 age and gender matched individuals. Serum ferritin and plasma BNP levels were assayed by ELISA . Results : TM patients had significant higher mitral inflow early diastolic (E) wave and non significant other conventional echo parameters. Pulsed wave TDI revealed systolic and diastolic dysfunctions in the form of significant higher isovolumetric contraction time (ICT) , ejection time ( E T) and isovolumetric relaxation time (IRT) with significantly lower mitral annulus early diastolic velocity E` (12.07 ±2.06 vs 15.04±2.65 ,P= 0.003) in patients compared to controls. Plasma BNP was higher in patients compared to the controls. Plasma BNP and serum ferritin had significant correlation with each other and with pulsed wave conventional and TDI indices of systolic and diastolic functions. Patients with E/E` ≥ 8 had significant higher serum ferritin and plasma BNP levels compared to those with E/E` ratio < 8 without difference in Hb levels . Conclusion : Pulsed wave TDI is an important diagnostic tool for latent cardiac dysfunction in iron loaded TM patients and is related to iron overload and BNP .