A bifrequent passive sensor system for measurement of the pulse wave velocity in a stent

Abstract

In-stent restenosis (ISR) is a frequent complication after stent implantation. Recently, a passive sensor system for integration into a stent has been presented, which is designed to detect an ISR early by measuring the local pulse wave velocity (PWV). This system is based on two pressure sensitive transponders, the resonance frequency of which hits the frequency of a magnetic field generated by an externally applied transceiver coil during a pulse cycle. This method is limited in applicability by the largest PWV it can measure. In this contribution a modified sensor system is investigated, which operates at two separate frequencies for each transponder. It has been shown that this modification solves the problem of limited PWV measurement range. Additionally, the previously developed model was shown to be valid for bifrequent operation. Furthermore, the influence of the system parameters on measurement precision have been investigated and verified in simulations.

Future of Smart Cardiovascular Implants

“…Several studies [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ] have all attempted to find reliable ways of diagnosing ISR by integrating additional components onto the stent. Due to restenosis, there is a local increase in pressure within the stent and this can be detected by a pressure sensor.…”

“…The stent (inductor) and sensor (capacitor) combination is inductively coupled to an external coil, and the phase-dip is measured. Schachtele [ 44 ] modified this approach by integrating two pressure sensitive transponders at either ends of the stent. The delay between resonances of the two transponders is used to calculate the local pulse wave velocity.…”