Noninvasive cardiac output measurement is inaccurate in patients with severe aortic valve stenosis undergoing transcatheter aortic valve implantation.

Abstract

Background\nNoninvasive cardiac output (CO) measurement using ClearSight™ (Edwards Lifesciences, Irvine, CA, US) eliminates the need for intra-arterial catheter insertion. However, the accuracy and reliability of this system have not been evaluated in severe aortic valve stenosis (AS).\n\n\nMethods\nThirty patients who underwent elective transcatheter aortic valve implantation (TAVI) were prospectively enrolled in this study. CO was simultaneously measured twice before and twice after valve deployment, for a total of four times per patient, and compared between the ClearSight (COClearSight) system and CO from the pulmonary artery catheter (PAC) thermodilution (COTD) as reference. Bland-Altman analysis was used to compare the percentage error between the measurement methods.\n\n\nResults\nA total of 112 paired data points were obtained. The percentage error between COClearSight and COTD was 43.1%. The paired datasets were divided into the following groups according to the systemic vascular resistance index (SVRI): low (<1,200 dyne s/cm5/m2) and normal (1,200-3,000 dyne s/cm5/m2). The percentage errors were 49.1% and 44.7%, respectively. The discrepancy in CO (COTD and COClearSight) was not significantly correlated with SVRI (r = -0.06, P < 0.001). Polar plot analysis showed an angular concordance rate of 51.1%. The tracking ability of COClearSight after artificial valve deployment was below the acceptable trending ability cut-off (92%).\n\n\nConclusion\nThe accuracy of CO measurement and its trending ability measured from ClearSight were not acceptable in patients with severe AS undergoing TAVI. The ClearSight system is therefore not interchangeable with PAC thermodilution for determining CO.