MATERIAL AND METHODS
Ethics committee approval was obtained in accordance with the Helsinki declaration. A total of 39 patients with BTM and 39 age and gender matched healthy children (control group) were enrolled in the study. Exclusion criteria were children with other chronic hemolytic anemia, cardiovascular diseases, congenital heart diseases, diabetes mellitus, hypertension and previously known renal diseases. Patients with hepatic diseases were also excluded.
Medical histories of all patients were recorded and physical examinations were performed. Complete blood count, reticulocytic count, serum ferritin and iron level, liver, renal function tests, plasma ADMA and endocan and proBNP. Cardiac examination results by a pediatric cardiologist were tested on all children in both patient and control groups. Beta globin chain gene mutation analysis and treatment regimens of patient group recorded. Circulating endocan and ADMA were determined with commercially available ELISA (enzyme-linked immunosorbent assay) kits (Wuhan USCN Business Co., Ltd., China.)
Echocardiographic investigations were performed in the Pediatric Cardiology Department of Konya Training and Research Hospital using General Electric Vivid S60 (General Electric Medical Systems, Horten, Norway) with 5.0 MHz transducers in our pediatric cardiology echocardiography laboratory by the same observer. A full echocardiography including conventional Doppler, color images, and M-mode measurements was performed. Echocardiograms were recorded on a flash drive for repeated evaluation. All measurements were performed according to the American Society of Echocardiography. Patients with any congenital or acquired heart disease identified on echocardiography were excluded from the study group.
Ejection fraction and fractional shortening of the left ventricle (LV), interventricular septum diastolic diameter, left ventricular end-systolic and end- diastolic diameter (LVESD and LVEDD), and left ventricular posterior wall diastolic thickness were measured from 2-dimensional- guided M-mode echocardiographic tracings. End-diastolic and end-systolic volumes were also used to calculate EF by Simpson biplane method from the apical 4- and 2-chamber views. The pulse-wave Doppler echocardiographic parameters were as follows: early (E) and late (A) mitral diastolic velocities. Tissue Doppler velocities were obtained from 3 locations; the sample vol- ume was positioned on the lateral aspect of each atrioventricular valve annulus and on the basal portion of interventricular septum. Peak early diastolic myocardial (e’), peak atrial systolic (a’), and peak systolic (s’) myocardial velocities were measured using this technique.
Patients older than 8 years were also evaluated with cardiac T2 * MR imaging in Department of Radiology by a pediatric radiologist. All MR scans were performed on a 1.5 T Magnetom Aera MR scanner (Siemens, Germany) using a 4-channel anterior phased array coilat single center. A transverse slice through the center of the liver was imaged using a multi-echo single breath-hold gradient echo T2* sequence with a range of echo times (TE 0.90-15.0 ms). Analysis was performed on a computer using Thalassemia - Tools software (a CMRtools plug-in; Cardiovascular Imaging Solutions, London, UK). Patients with a cardiac T2 * value of 15-20 ms and mild iron overload were grouped as mild, those with 8-14 ms as moderate, and those with <8 ms as severe.