In order to test whether dialyzer membrane biocompatibility influences systemic cardiovascular function, we treated 8 hemodialysis patients (4 men and 4 women, aged 24-73 years) with a low-biocompatible (cuprophane) and a high-biocompatible (polyacrylonitrile) membrane in a randomized double-blind crossover protocol using bicarbonate hemodialysis without ultrafiltration for the first 60 min and with ultrafiltration for the remaining treatment time. Left ventricular function and systemic hemodynamics were assessed noninvasively at baseline and during treatment by Doppler echocardiography combined with external subclavian artery pulse trace calibrated with oscillometrically measured brachial artery blood pressures. There was no significant difference in the cardiovascular response to the 2 membranes, neither during isolated hemodialysis nor when ultrafiltration was added. Mean arterial pressure increased 10% (p < 0.001) during isolated hemodialysis and returned to baseline levels with ultrafiltration. The cardiac index decreased 22 % (p < 0.001) during ultrafiltration, due to the greater decrease in left ventricular stroke index (30%, p < 0.001) than increase in heart rate (9%, p < 0.05). Total peripheral resistance increased 10% (p < 0.05) during isolated hemodialysis and a further 19% (p < 0.01) when ultrafiltration was added. Hence, profound cardiovascular alterations were observed during hemodialysis treatment; however, these changes were not related to the biocompatibility of the membranes.
A method for quantitative LV wall motion analysis based on 3-D reconstruction of the LV endocardial surface is presented. The reconstruction is based on a minimum of three transthoracic apical 2-D cineloops of the LV, digitally transferred from the ultrasound scanner to a computer. Images are obtained by rotating the transducer around the LV long axis. Endocardial borders are traced with an automatic edge detection algorithm with manual correction. These borders are used with a specially designed computer algorithm for reconstruction of LV cavity 3-D shape, and LV volumes, ejection fraction, and endocardial surface area can be determined. The end-diastolic and end-systolic endocardial surfaces are compared for analysis of regional wall motion. A threshold value is selected to discriminate between normal and abnormal wall motion. Regional wall motion abnormalities are displayed in a bull's eye plot, and the corresponding endocardial surface area is expressed in percent of the total endocardial area. Phase analysis is performed from reconstruction of the endocardial surface throughout the cardiac cycle, and displays regions with abnormal wall motion as being out of phase with LV volume variation. Thus, LV 3-D reconstruction performed by this method can be used for quantitative analysis of wall motion in several clinical situations, and due to the simplicity of processing the data, can be useful outside the research laboratory.
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