Non-invasive measurement of cardiac output in children with repaired coarctation of the aorta using electrical cardiometry compared to transthoracic Doppler echocardiography

Abstract

Objective: To evaluate the equivalence of the ICON® electrical cardiometry (EC) haemodynamic monitor to measure cardiac output (CO) relative to transthoracic Doppler echocardiography (TTE) in paediatric patients with repaired coarctation of the aorta (CoA). Approach: A group of n = 28 CoA patients and n = 27 matched controls were enrolled. EC and TTE were performed synchronously on each participant and CO measurements compared using linear regression and Bland–Altman analysis. The CoA group was further subdivided into two groups, with n = 10 and without n = 18 increased left ventricular outflow tract velocity (iLVOTv) for comparison. Main results: CO measurements from EC and TTE in controls showed a strong correlation (R = 0.80, p < 0.001) and an acceptable percentage error (PE) of 28.1%. However, combining CoA and control groups revealed a moderate correlation (R = 0.57, p < 0.001) and a poor PE (44.2%). We suspected that the CO in a subset of CoA participants with iLVOTv was overestimated by TTE. Excluding the iLVOTv CoA participants improved the correlation (R = 0.77, p < 0.001) and resulted in an acceptable PE of 31.2%. Significance: CO measurements in paediatric CoA patients in the absence of iLVOTv are clinically equivalent between EC and TTE. The presence of iLVOTv may impact the accuracy of CO measurement by TTE, but not EC.