Evaluation of Intracardiac Pressures Using Subharmonic-aided Pressure Estimation with Sonazoid Microbubbles

Area of Science:

• Cardiovascular Imaging and Diagnostics
• Ultrasound Contrast Agents
• Hemodynamic Monitoring

Background:

• Accurate measurement of right ventricular (RV) systolic and left ventricular (LV) diastolic pressures is crucial for diagnosing and managing cardiovascular diseases.
• Current methods often rely on invasive cardiac catheterization, which carries inherent risks and limitations.
• Noninvasive techniques are sought to provide safer and more accessible hemodynamic assessments.

Purpose of the Study:

• To evaluate the feasibility of the subharmonic-aided pressure estimation (SHAPE) technique for noninvasively determining RV systolic and LV diastolic pressures.
• To assess the accuracy of SHAPE using Sonazoid microbubbles compared to standard cardiac catheterization methods.

Main Methods:

• A prospective clinical trial enrolled patients undergoing left and/or right heart catheterization.
• Sonazoid microbubbles were administered intravenously, and SHAPE data were acquired synchronously with invasive pressure measurements (fluid-filled and solid-state catheters).
• A conversion factor derived from cuff-based pressure and aortic subharmonic signals was used to translate SHAPE signals into pressure values.

Main Results:

• The SHAPE technique demonstrated mean errors of 1.6 mm Hg ± 1.5 for RV systolic pressure and 8.4 mm Hg ± 6.2 for LV minimum diastolic pressure compared to fluid-filled catheters.
• Errors for LV end-diastolic pressure were 7.4 mm Hg ± 5.7 (vs. fluid-filled) and 6.8 mm Hg ± 3.3 (vs. solid-state).
• The SHAPE technique showed potential for clinically relevant pressure measurements, with P-values indicating statistical significance or near-significance for most comparisons.

Conclusions:

• The SHAPE technique, when used with Sonazoid microbubbles, shows potential for noninvasive estimation of RV systolic and LV diastolic pressures.
• This noninvasive approach may offer a valuable alternative to invasive cardiac catheterization for hemodynamic assessment.
• Further validation and clinical implementation are warranted to establish its role in cardiovascular diagnostics.