Extravascular Blood Pressure Monitoring with Circumferential vs. Radial Artificial Aortic Baroreceptors

Area of Science:

• Biomedical Engineering
• Cardiovascular Physiology
• Sensor Technology

Background:

• Aortic baroreceptors are crucial for cardiovascular autoregulation, sensing blood pressure changes via vascular wall stretch.
• Existing blood pressure monitoring methods have limitations, necessitating novel approaches inspired by natural mechanisms.

Purpose of the Study:

• To develop and evaluate artificial aortic baroreceptors (AABs) that replicate the stretch-based pressure sensing of natural baroreceptors.
• To assess the performance of two AAB designs, one for circumferential and one for radial sensitivity, in monitoring aortic blood pressure.

Main Methods:

• Two AABs, C-AAB and R-AAB, were created using MEMS pressure sensors and silicone probes integrated into a synthetic aorta.
• Performance metrics including linearity, sensitivity, hysteresis, and accuracy were evaluated across a physiological pressure range (0-180 mmHg).
• Aortic blood pressure waveforms were monitored in a synthetic aorta under controlled conditions.

Main Results:

• The R-AAB exhibited a linear response, while the C-AAB showed a quadratic response to pressure changes.
• The C-AAB demonstrated significantly higher sensitivity (ten-fold) and lower error (0.91 mmHg RMSE) compared to the R-AAB (0.093 mmHg sensitivity, 1.6 mmHg RMSE).
• Both AABs accurately monitored physiological blood pressure waveforms, with C-AAB showing superior performance.

Conclusions:

• The developed AABs successfully mimic natural aortic baroreceptors' blood pressure sensing capabilities.
• The C-AAB's superior sensitivity suggests natural baroreceptors may be more sensitive to circumferential stretch.
• These AABs offer potential for advanced in-vitro and in-vivo cardiovascular and blood pressure monitoring applications.