Wireless blood pressure monitoring with a novel implantable device: long-term in vivo results.
OBJECTIVE
Devices constantly tracking the blood pressure (BP) of hypertensive patients are highly desired to facilitate effective patient management and to reduce hospitalization. We report on experiences gathered in a pilot study that was designed to evaluate the prototype of a newly developed, minimally invasive implantable sensor system for long-term BP monitoring.


METHODS
The device was implanted in the femoral artery (FA) of 12 sheep via standard FA catheterization under fluoroscopic control. Accuracy of the recorded blood pressure was determined by comparison with a reference catheter, which was positioned in the contralateral FA immediately after implantation. Regular follow-up included angiography, computed tomography (CT), and control of functionality and position of the BP sensor. Animals were euthanized after 6 months. FA segments with in situ pressure sensor underwent macroscopic and histopathologic examinations.


RESULTS
All implantations of the novel sensor device in the FA were successful and uneventful. High-quality BP recordings were documented. Bland-Altman plots indicate very good agreement. Comparison with measurements taken from the reference sensor revealed mean differences and standard deviations of -0.56 ± 0.85, 0.29 ± 1.44, and 0.85 ± 2.27 mmHg (diastolic, systolic, and pulse pressure, respectively) after exclusion of one outlier. CT uncovered deficiencies in cable stability that were addressed in a redesign. No thrombus formation, necrosis, or apoptosis were detected.


CONCLUSIONS
The pilot study proved the technical feasibility of wireless BP measurement in the FA via a novel miniature sensor device.
Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz-Institute, RWTH Aachen University, Pauwelsstraße 20, 52074, Aachen, Germany, nina.cleven@rwth-aachen.de.
Nina J
NJ
Cleven
Peter
P
Isfort
Tobias
T
Penzkofer
Anna
A
Woitok
Benita
B
Hermanns-Sachweh
Ulrich
U
Steinseifer
Thomas
T
Schmitz-Rode
D000792:Angiography; D000818:Animals; D018660:Blood Pressure Monitoring, Ambulatory / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D005263:Femoral Artery; D005471:Fluoroscopy; D008904:Miniaturization; D012756:Sheep; D013686:Telemetry