Noninvasive Evaluation of Cardiac Chamber Pressures Using Subharmonic-Aided Pressure Estimation With Definity Microbubbles

BACKGROUND Noninvasive and accurate assessment of intracardiac pressures has remained an elusive goal of noninvasive cardiac imaging. OBJECTIVES The purpose of this study was to investigate if errors in intracardiac pressures obtained noninvasively using contrast microbubbles and the subharmonic-aided pressure estimation (SHAPE) technique are < 5 mm Hg. METHODS In a nonrandomized institutional review board-approved clinical trial (NCT03243942), patients scheduled for a left-sided and/or right-sided heart catheterization procedure and providing written informed consent were included. A standard-of-care catheterization procedure was performed advancing clinically used pressure catheters into the left and/or right ventricles and/or the aorta. After pressure catheter placement, patients received an infusion of Definity microbubbles (n = 56; 2 vials diluted in 50 mL of saline; infusion rate: 4-10 mL/min) (Lantheus Medical Imaging). Then SHAPE data was acquired using a validated interface developed on a SonixTablet scanner (BK Medical Systems) synchronously with the pressure catheter data. A conversion factor (mm Hg/dB) was derived from SHAPE data and measurements with a SphygmoCor XCEL PWA device (ATCOR Medical) and was combined with SHAPE data from the left and/or the right ventricles to obtain clinically relevant systolic and diastolic ventricular pressures. RESULTS The mean value of absolute errors for left ventricular minimum and end diastolic pressures were 2.9 +/- 2.0 and 1.7 +/- 1.2 mm Hg (n =26), respectively, and for right ventricular systolic pressures was 2.2 +/- 1.5 mm Hg (n = 11). Two adverse events occurred during Definity infusion; both were resolved. CONCLUSIONS These results indicate that the SHAPE technique with Definity microbubbles is encouragingly efficacious for obtaining intracardiac pressures noninvasively and accurately. (Noninvasive, Subharmonic Intra-Cardiac Pressure NCT03243942) (J Am Coll Cardiol Img 2023;16:224-235) (c) 2023 by the American College of Cardiology Foundation.

Automated summary

This study investigates the accuracy of noninvasive intracardiac pressure assessment using contrast microbubbles and the subharmonic-aided pressure estimation (SHAPE) technique. The results show that SHAPE technique with contrast microbubbles is efficacious for obtaining intracardiac pressures noninvasively and accurately.