An integrated stent-graft for noninvasive 4-dimensional aneurysm sac pressure monitoring after endovascular aortic aneurysm repair (EVAR): First in vivo results in a porcine model

Purpose In vivo testing of a prototypic stent-graft with an integrated network of pressure sensors covering the external surface of the implant and capable of wireless digital data transmission for non-invasive measurement of aneurysm sac pressure following endovascular aortic aneurysm repair (EVAR). Materials and Methods Based on a commercially available aortic stent-graft we constructed a prototype with silicon-based pressure sensors fitting into a standard 24 F delivery sheath. Digital data conversion is performed by an integrated microcontroller, energy and data transfer by inductive coupling. All microelectronic devices are integrated on the implant: No further procedural steps are necessary. The prototype was tested in 4 swine by placing the (mono-iliac) graft across the iliac trifurcation with at least one sensor at the level of the occluded branches and performing invasive reference pressure measurement in the occluded (contra-lateral) arterial lumen following graft placement. Results Graft placement was successful in all 4 animals, transcutaneous wireless energy and data transmission was successfully demonstrated. The experiments revealed good correlation of the pressure-data changes acquired by the sensor at the level of the iliac trifurcation to the reference measurement. Conclusion The non-invasive acquisition of a sac pressure profile after EVAR by integrating the detectors on the external surface of the stent-graft allows detecting a regional pressure elevation, as in early endoleakage, and is a practical and efficient option for continous and direct pressure monitoring. Further development and implementation into a product is aimed.