An implantable Fabry-Pérot pressure sensor fabricated on left ventricular assist device for heart failure

Abstract

Continuous flow left ventricular assist devices (LVADs) are commonly used as bridge-to-transplantation or destination therapy for heart failure patients. However, non-optimal pumping speeds can reduce the efficacy of circulatory support or cause dangerous ventricular arrhythmias. Optimal flow control for continuous flow LVADs has not been defined and calls for an implantable pressure sensor integrated with the LVAD for real-time feedback control of pump speed based on ventricular pressure. A MEMS pressure sensor prototype is designed, fabricated and seamlessly integrated with LVAD to enable real-time control, optimize its performance and reduce its risks. The pressure sensing mechanism is based on Fabry-Pérot interferometer principle. A biocompatible parylene diaphragm with a silicon mirror at the center is fabricated directly on the inlet shell of the LVAD to sense pressure changes. The sensitivity, range and response time of the pressure sensor are measured and validated to meet the requirements of LVAD pressure sensing.

Fiber-optic combined FPI/FBG sensors for monitoring of radiofrequency thermal ablation of liver tumors: ex vivo experiments

“…Several EFPI-based configurations have been recently presented [21][22][23][24][25][26][27][28]; in addition, EFPI-based medical devices are commercially available [29]. It is possible to combine an EFPI probe with a fiber Bragg grating (FBG) [30,31], acting as temperature sensor in proximity of the EFPI sensor, to provide a dual sensing with cross compensation; such configuration has been proposed in [26][27][28].…”

Management of ventricular arrhythmias in patients with ventricular assist devices

“…Moving forward, additional studies relating the clinical occurrence of ventricular arrhythmias to molecular and physiological shifts within the myocardium will be invaluable in better defining which mechanisms are most strongly implicated in the time-dependent risks of ventricular arrhythmias in VAD-supported hearts. Further device evolution, including inflow cannula modifications [19,63] and inlet pressure control systems that adjust rotor speeds and prevent suction [23,[64][65][66], may reduce the incidence of ventricular arrhythmias among VAD-supported patients. Prospective trials assessing the benefits of de-novo prophylactic ICD placement and the need to replace ICDs in patients free of post-VAD ventricular arrhythmias would be particularly welcome.…”

Review of fiber-optic pressure sensors for biomedical and biomechanical applications

“…139 Recently, another F-P sensor was successfully tested in vitro and proposed for continuous flow left ventricular assist devices (LVAD). 141 The F-P cavity consisted of a biocompatible parylene diaphragm and a silicon mirror fabricated directly on the inlet shell of the LVAD device. Sensor sensitivity (1 mmHg achieved by fringe counting; less than 0.1 mmHg with interpolation), linear range (up to 100 mmHg) and response time (1 ms; limited by the response time of the optical detector and the self-resonance frequency of the parylene-C membrane) meet the requirements of LVAD pressure-sensing systems.…”

“…Sensor sensitivity (1 mmHg achieved by fringe counting; less than 0.1 mmHg with interpolation), linear range (up to 100 mmHg) and response time (1 ms; limited by the response time of the optical detector and the self-resonance frequency of the parylene-C membrane) meet the requirements of LVAD pressure-sensing systems. 141 Nevertheless, further improvements are mandatory for animal and human testing. In this case, however, authors have pointed the necessary steps to accomplish it.…”

“…In this case, however, authors have pointed the necessary steps to accomplish it. 141 Several companies, such as FISO Technologies (Québec, Canada), Arrow International, Inc. and MAQUET Getinge Group (Rastatt, Germany), are providing F-P based sensors to monitor the arterial pressure during IAB pump therapy. FISO Technologies is recommending the fiber optic pressure (FOP)-MIV sensor (550 μm OD).…”