Benchtop Pulse Wave Velocity Measurement From Spatial Wavelength Rather Than Pulse Arrival Time: Feasibility Studies

Arterial stiffness is a significant predictor of cardiovascular disease, commonly assessed using pulse wave velocity (PWV). Traditional PWV measurement methods, such as time-of-flight, become unreliable in highly reflective systems due to the presence of standing waves and measurement noise, complicating accurate determination of wave arrival times. To address these limitations, we developed and validated a spatial wavelength-based PWV measurement approach. Our objective was to evaluate the capability of this method in nonbiological systems and compare its performance directly to standard methods. Experimental measurements were conducted using latex tubes in a benchtop pulsatile flow system across multiple frequencies (20-47 Hz). High-speed video analysis tracked spatial diameter changes, allowing identification of the spatial wavelength. Computational fluid-structure interaction (FSI) simulations, replicating experimental conditions, provided validation. Measuring PWV via spatial wavelength showed consistent accuracy when compared to traditional methods (phase-slope, peak-slope, and pressure arrival time), remaining within 12% error relative to theoretical predictions derived from the Moens-Korteweg equation. Spatial wavelength-based calculation has practical limitations, including reduced reliability near resonant frequencies and the requirement for at least one full wavelength within the length of measured region, constraining clinical usability. This method can be used in laboratory conditions at higher frequencies, potentially allowing quantification of how vascular implants and prosthetics could alter arterial wall dynamics.