Assessing the Role of Tissue Doppler in the Detection of Myocardial Dysfunction in Patients with B-Thalassemia Major

Abstract

Thalassemia is a hereditary anemia characterized by anomalies in the synthesis of one or more of the globin chains of normal hemoglobin. Blood transfusion is lifesaving in these patients, but it can be increased the risk of viral infection and iron overload. Iron overload causes severe and permanent cardiac damage even more than untreated anemia including recurrent pericarditis, recurrent forms of heart block, ectopic ventricular beats, ventricular tachycardia, ventricular fibrillation, cardiomegaly, left ventricular (LV) dysfunction and finally heart failure resistant to any therapeutic measures. Tissue Doppler imaging can detect regional systolic and diastolic myocardial dysfunction earlier than global dysfunction in thalassemia patients. The main aim of this study was to assess the role of tissue Doppler in the detection of myocardial dysfunction secondary to iron overload in B-thalassemia major patients when compared to conventional echocardiography. This case control study included 30 thalassemia patients (23 males and 7 females) with mean of age 15.233± 4.415 years, selected among cases followed by the Hematology clinic of Ain Shams Faculty of Medicine Children Hospital. Consent was obtained from parents after explanation of the aim of the study. All patients were subjected to full history taking, full examination, laboratory investigations including mean serum ferritin levels in the last year, mean Hb level in the last year, ALT, AST, echocardiographic assessment and Pulsed wave Tissue Doppler Imaging. Patient group were well matching control group in their age and gender. No difference found between both group in their anthropometric measures. Results of the current study show that: • Fourteen patients (46.7%) were non pubertal and 16 (53.3%) were pubertal. • Nineteen patients (63.3%) had spleenectomy and 18 (60%) had enlarged liver. • Regarding laboratory data there was statistically significant lower Hb% and higher serum ferritin and ALT in study group compared to control group (p=0.000, 0.000 & 0.002 respectively) • Regarding diastolic function, 2 (6.7%) patients in the study group had abnormal diastolic functions by Echo and all control group had normal diastolic function and this difference was of no significance statistically (p=0.246). • Results of the current study show statistically significant higher LAD and LVEDD in study group compared to control group. Non statistically significant difference between study and control groups regarding all other ECHO findings was observed. • Results of the current study show statistically significant lower BLWS, BASS, BPSS, MLWS, MASS AND MPSS in study group compared to controls indicating lower systolic function in patients. Also results of the current study show higher BIWA, BPSA, MPWA and MASA in study group compared to controls indicating more diastolic dysfunction in patients. From results of the current study we can recommend routine follow up of serum ferritin in thalassemic patients to decrease complications of iron overload and routine cardiological examination for thalassemic patients even when asymptomatic for early prediction of any systolic or diastolic dysfunction.Tissue Doppler allows identifying left ventricular diastolic alterations in asymptomatic patients with thalassemia major and should be include to regular investigations.