An Integrated I2C Sensor Network for Transcatheter Heart Valves

Abstract

Transcathether aortic heart valve replacement (TAVR) is a widespread approach to treating patients with severe aortic stenosis. A TAVR implant is ideally positioned to access numerous clinically relevant signals including arterial blood pressure, pulse wave velocity, electrocardiogram (ECG), patient motion, heart rate, respiration, and blood oxygenation. Unlike medical devices such as pacemakers, TAVR implants are purely mechanical structures with no sensing capabilities. In this work, we address this unmet clinical need by incorporating an Inter-Integrated Circuit (I2C) sensor network within a TAVR stent frame and designing sensor modules that can physically connect to the network at various landing zones. To illustrate this approach, we designed and built a sensor circuit board populated with a commercial inertial measurement unit (IMU) that can detect clinically useful metrics including pulse wave velocity at the aortic root. We use two spatially separated accelerometers to measure pulse wave propagation time with a standard deviation of 140 μs, which translates to an uncertainty of the pulse wave velocity of +/-0.2 m/s. The sensor modules connect to a customized stent frame containing the necessary I2C conductors. Our data suggest that a fully instrumented TAVR paradigm is feasible using this frame design and modular sensor approach.