Battery-less implantable sensor for real-time intrasac pressure monitoring in EVAR-treated AAAs

To develop and bench-validate a fully passive, wireless implantable pressure monitoring system (WIPS) for on-demand assessment of intra-sac pressure in patients with endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms. WIPS includes a flexible 15 mm × 145 mm implant integrating four pressure sensors (MS5839), an RFID tag (ST25DV04KC), and an ultra-low-power microcontroller (STM32L011). The device is powered wirelessly via 13.56 MHz RFID, enabling pressure measurements at configurable resolutions without need for batteries. Data is stored locally and retrieved via an external Reader (RD520). Benchtop tests evaluated power consumption, telemetry range, and sensor linearity in air, heated saline, and a biologically representative meat model. Uniform 1 μm and 2 μm Parylene C coatings were applied intentionally, as two predefined thickness conditions, to evaluate biocompatibility without compromising sensor performance. Total power consumption remained below 4 mW across all oversampling ratios (OSRs). In free air, reliable telemetry was achieved up to 24 cm at 6 W Reader output. Heated mineral water reduced the optimal distance to 16 cm, and physiological saline limited it to 4 cm. In the Meat Model, a fixed 18 cm tissue path yielded 100% link reliability for OSR ≤ 1024 at 5 W. Parylene C coatings did not alter pressure linearity or hysteresis. The strip is compatible with a 20 F delivery sheath, suggesting compatibility with standard EVAR catheters. WIPS combines low power consumption, deep-tissue wireless telemetry, and catheter-based deliverability, addressing longstanding limitations in implantable EVAR surveillance tools. These benchtop findings support feasibility for future in vivo testing in large animal models to validate long-term safety and clinical integration. • Abdominal Aortic Aneurysm (AAA) has a high rupture risk if untreated • Wireless pressure monitoring could enhance post-EVAR surveillance and reduce reliance on costly imaging • Fully passive, battery-less wireless sensor enables real-time intrasac pressure monitoring in EVAR-treated AAAs • Optimized RFID matching network achieves reliable read range through tissue-mimicking media • In vitro and ex vivo tests demonstrate accurate pressure tracking and sensor stability