Dual-Modality Volume Measurement Integrated on a Ventricular Assist Device

Area of Science:

• Biomedical Engineering
• Medical Devices
• Cardiovascular Technology

Background:

• Ventricular assist devices (VADs) are crucial for end-stage heart failure patients.
• Real-time volume monitoring is vital for personalized VAD therapy.
• Single-modality volume measurement requires frequent recalibration post-VAD implantation.

Purpose of the Study:

• To develop a robust, calibration-free ventricular volume measurement technique.
• To integrate ultrasound and electric impedance into a VAD cannula.
• To assess the accuracy and reliability of a dual-modality approach.

Main Methods:

• Integrated ultrasound and impedance sensors into an apical VAD cannula.
• Tested dual-modality system with silicon heart phantoms (140-420 mL) under physiological pressures.
• Compared dual-modality results with single-modality and standard calibrated measurements using cross-validation.

Main Results:

• The dual-modality approach achieved superior limits of agreement (-0.83 ± 1.54%).
• Ultrasound alone showed -13.88 ± 5.90% LOA, and impedance alone showed -43.45 ± 10.28% LOA.
• Dual-modality measurements were as accurate as standard calibrated methods.

Conclusions:

• Dual-modality ventricular volume measurement using ultrasound and impedance enhances robustness.
• This integrated approach eliminates the need for recalibration in VAD patients.
• Accurate ventricular volume measurement is achievable during the critical post-VAD implantation period, even with remodeling.