An Implantable Intravascular Pressure Sensor for a Ventricular Assist Device

Area of Science:

• Biomedical Engineering
• Medical Devices
• Sensor Technology

Background:

• Ventricular assist devices (VADs) require precise hemodynamic monitoring.
• Existing pressure sensors may have limitations in size, biocompatibility, or continuous monitoring capabilities.

Purpose of the Study:

• To develop and validate an intravascular micro-electro-mechanical system (MEMS) pressure sensor for direct hemodynamic measurement in VADs.
• To assess the sensor's biocompatibility, stability, and performance in vitro and in vivo.

Main Methods:

• Utilized a ceramic thick film process for bio- and hemo-compatible packaging of a sub-millimeter piezoresistive sensor.
• Applied polydimethylsiloxane (PDMS) and parylene-C coatings to the sensor.
• Developed a low-power, small-form-factor electronic circuit for signal conditioning and read-out.
• Conducted extensive in vitro testing with saline solution and in vivo validation in a female sheep model.

Main Results:

• The packaged sensor achieved a compact size (2.6 mm x 3.6 mm x 1.8 mm) with low power consumption (<14.5 mW).
• Demonstrated temperature-independent sensitivity (12 μV/V/mmHg) and excellent in vitro stability (drift <0.05 mmHg/day).
• Successfully recorded arterial pressure waveforms in vivo, validating its use for continuous blood pressure monitoring.

Conclusions:

• A novel, small, intravascular MEMS pressure sensor has been successfully developed and validated for VAD applications.
• The sensor provides continuous, accurate blood pressure monitoring at VAD inflow and outflow sites.
• This technology holds promise for improved VAD management and patient outcomes.