ABSTRACT 557

Abstract

Background and aims: Analysis of right ventricular function in patients with a left ventricular assist device (LVAD) is essential when establishing long-term prognosis and evaluating the indication for right ventricular support. Aims: The objective of the study was to compare measurement of cardiac output using the ultrasound cardiac output monitor (USCOM) with measurements obtained using chest ultrasound and a thermodilution catheter. Methods: We performed a prospective study of 2 pediatric patients with LVAD (EXCOR® and Levitronix®). Local Institutional Review Board waived the need for informed consent. For the initial validation, measurements obtained with USCOM (transducer towards the center of the cannula) were compared to those obtained with real EXCOR® flow (25-ml pump X HR [5 bpm]). Indexed cardiac output (iCO) obtained using the USCOM device with the transducer positioned for pulmonary valve flow acquisition was applied for further comparison with transthoracic echocardiography data (VTI x πr2 x HR) (EXCOR® patient) and thermodilution catheter data (Levitronix® patient). Measurements were made by 2 observers in order to compare the degree of interobserver correlation. Results: We obtained 88 measurements. The results from the initial validation were as follows: iCO USCOM 2.5 l/min/m2 (2–2.8) vs EXCOR® 3 l/min/m2 (p=0.4). The results from comparisons of the noninvasive techniques were as follows: 1) EXCOR® iCO USCOM vs echocardiography, 6.1 l/min/m2 (5.2–7.3) vs 6.5 (5.5–7.16) (p=0.9); 2) Levitronix® iCO USCOM vs thermodilution catheter, 3.8 l/min/m2 (2.8–4.3) vs 3 l/min/m2 (2.9–3.1) (p=1). Interobserver correlation was substantial (k=0.8). Conclusions: Measurement of cardiac output using USCOM provides reliable data compared with the real value of GC. Interobserver agreement is very high.