Stroke volume determination using transcardiopulmonary thermodilution and arterial pulse contour analysis in severe aortic valve disease

PURPOSE: Transcardiopulmonary thermodilution (TPTD, SVTD) as well as calibrated (SVPC CAL) and uncalibrated (SVPC UNCAL) arterial pulse contour analysis (PC) are increasingly promoted as less-invasive technologies to measure stroke volume (SV) but their reliability in aortic valve disease was unknown. The objective of this prospective study was to investigate the validity of three less-invasive techniques to assess SV in conditions involving aortic stenosis (AS) and valvuloplasty-induced aortic insufficiency (AI) compared with transesophageal echocardiography.

METHODS: In 18 patients undergoing transcatheter aortic valve implantation, SVTD and SVPC CAL were determined using a central pressure signal via the brachial artery and SVPC UNCAL using a peripheral radial signal.

RESULTS: In aortic valve dysfunction TPTD achieved adequate reproducibility (concordance correlation coefficient (CCC): AS 0.84; AI 0.82) and agreement (percentage error (PE): AS 26.3 %; AI 26.2 %) with the reference technique. In severe AS, SVPC CAL (PE 25.7 %; CCC 0.85) but not SVPC UNCAL (PE 50.4 %; CCC 0.38) was reliable. Neither calibrated nor uncalibrated PC (SVPC CAL: PE 51.5 %; CCC 0.49; SVPC UNCAL: PE 61.9 %; CCC 0.22) was valid in AI. Trending ability to hemodynamic changes, quantified by the ΔSV vector and the angle θ, was acceptable for each measurement modality.

CONCLUSIONS: Transcardiopulmonary thermodilution is valid in aortic valve dysfunction. Calibration of PC substantially improves reliability in aortic valve disease. Calibrated PC is valid in severe AS. Valvuloplasty-induced AI seriously confounds PC measurements. In uncalibrated PC approaches, the relative SV trend is superior to single absolute values.