2.2 Conventional Echocardiography
Blood pressure, heart rate, and BSA measurements of all the individuals were recorded before the examination. Echocardiography was performed by an experienced cardiologist during the recovery period post-HD. Subjects were in the left lateral decubitus position, aspirated calmly, and connected with synchronous electrocardiogram. The measurements were carried out using the echocardiography machine (Vivid E95; GE Healthcare, Horten, Norway) and a 5S (3.5-5Mhz) probe.
Images included 2D, M-mode, pulsed-, and continuous-wave Doppler in addition to Tissue Doppler Imaging (TDI) were obtained from the standard parasternal and apical positions according to the guidelines of the American Society of Echocardiography (ASE). Zoomed LA were obtained in 4-and 2-chamber views at high frame rates (60-80 frames/sec), and three consecutive cardiac cycles were stored. LAV (maximum[max], maximum[min]), 2D LAEF were measured by biplane Simpson’s method. LA diameter, including antero-posterior diameter (LAD1), medial-later diameter (LAD2), and superior-inferior diameter (LAD3) were measured from left ventricular long axis and apical 4 chamber. Left ventricle end diastolic dimensions (LVEDd), interventricular septum diastolic thickness (IVST), posterior wall diastolic thickness (PWT) and LVEF were measured by M-mode method.
Left ventricle diastolic function was assessed: Peak E and A velocity were measured by pulsed-wave doppler at the mitral leaflet tips in the apical 4-chamber view, and the E/A ratio was calculated. TDI velocities early diastole (e’) were recorded with the sample volume placed on the septal and lateral mitral annulus, and E/e’ was calculated. Pulmonary capillary wedge pressure (ePCWP) was calculated according to the following formula: ePCWP = 1.25(E/E’) + 1.9[5]. Pulmonary artery systolic pressure(PASP) was estimated with the Bernoulli equation formula: 4xTRv2 + RAP, where v is the peak tricuspid regurgitation velocity, measured by continuous-wave Doppler, added to the estimated right atrium pressure, which was calculated based on inferior vena cava (IVC) diameter and the extent of its collapse during inspiration. [6]