OBJECTIVEIt is known that continuous glucose monitoring (CGM) systems can lower mean glucose compared with episodic self-monitoring of blood glucose. Implantable CGM systems may provide additional benefits. RESEARCH DESIGN AND METHODSWe studied the Eversense (Senseonics Inc.) implantable CGM sensor in 71 participants aged 18 years and older with type 1 and type 2 diabetes in a 180-day multinational, multicenter pivotal trial. Participants used the CGM system at home and in the clinic. CGM accuracy was assessed during eight in-clinic visits with the mean absolute relative difference (MARD) for venous reference glucose values >4.2 mmol/L as the primary end point. Secondary end points included Clarke Error Grid Analysis and alarm performance. The primary safety outcome was device-related serious adverse events. This trial is registered with ClinicalTrials .gov, number NCT02154126. RESULTSThe MARD value against reference glucose values >4.2 mmol/L was 11.1% (95% CI 10.5, 11.7). Clarke Error Grid Analysis showed 99.2% of samples in the clinically acceptable error zones A and B. Eighty-one percent of hypoglycemic events were detected by the CGM system within 30 min. No device-related serious adverse events occurred during the study. CONCLUSIONSOur results indicate the safety and accuracy of this new type of implantable CGM system and support it as an alternative for transcutaneous CGM.People with diabetes frequently use fingerstick capillary glucose measurements to guide their dosing decisions (1). Continuous glucose monitoring (CGM) systems can provide glucose data in real time and reduce the need for fingerstick testing (2). Additionally, people with diabetes can receive temporal information, trend information, and alarms for impending hypoglycemic and hyperglycemic events (2). When used regularly, CGM can effectively lower mean glucose compared with fingerstick glucose measurements only (3). Unfortunately, wear time of current transcutaneous CGM is low in some populations, which might partially be explained

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A continuous glucose monitoring (CGM) system consisting of a wireless, subcutaneously implantable glucose sensor and a body-worn transmitter is described and clinical performance over a 28 day implant period in 12 type 1 diabetic patients is reported. The implantable sensor is constructed of a fluorescent, boronic-acid based glucose indicating polymer coated onto a miniaturized, polymer-encased optical detection system. The external transmitter wirelessly communicates with and powers the sensor and contains Bluetooth capability for interfacing with a Smartphone application. The accuracy of 19 implanted sensors were evaluated over 28 days during 6 in-clinic sessions by comparing the CGM glucose values to venous blood glucose measurements taken every 15 min. Mean absolute relative difference (MARD) for all sensors was 11.6 ± 0.7%, and Clarke error grid analysis showed that 99% of paired data points were in the combined A and B zones.

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Background: Use of continuous glucose monitoring (CGM) systems is being rapidly adopted as standard of care for insulin-requiring patients with diabetes. The PROMISE study (NCT03808376) evaluated the accuracy and safety of the next-generation implantable Eversense CGM system for up to 180 days. Methods: This was a prospective multicenter study involving 181 subjects with diabetes at 8 USA sites. All subjects were inserted with a primary sensor. Ninety-six subjects had a second sensor, either an identical sensor or a modified sensor (sacrificial boronic acid [SBA]), inserted in their other arm (53 and 43 subjects, respectively). Accuracy was evaluated by comparing CGM to YSI 2300 glucose analyzer (Yellow Springs Instrument [YSI]) values during 10 clinic visits (day 1-180). Confirmed event detection rates, calibration stability, sensor survival, and serious adverse events (SAEs) were evaluated. Results: For primary sensors, the percent CGM readings within 20%/20% of YSI values was 92.9%; overall mean absolute relative difference (MARD) was 9.1%. The confirmed alert detection rate at 70 mg/dL was 93% and at 180 mg/dL was 99%. The median percentage of time for one calibration per day was 56%. Sixty-five percent of the primary sensors survived to 180 days. For the SBA sensors, the percent CGM readings within 20%/20% of YSI values was 93.9%; overall MARD was 8.5%. The confirmed alert detection rate at 70 mg/dL was 94% and at 180 mg/dL was 99%. The median percentage of time for one calibration per day was 63%. Ninety percent of the SBA sensors survived to 180 days. No device-or insertion/removal procedure-related SAEs were reported. Conclusion: These data show the next-generation Eversense CGM system had sustained accuracy and safety up to 180 days, with an improved calibration scheme and survival, using the primary or SBA sensors.

This paper reports a micromachined antenna stent (stentenna) that is integrated with implantable microsensors for wireless sensing of blood flow and pressure with no battery. A device that has 20-mm length and 3.5-mm diameter (after expansion) is fabricated from 50 pm thick stainless steel foil by using batch-compatible micro-electro-discharge machining. This is coupled to two micromachined capacitive pressure sensors of approximately 1.4x1.8x0.5 mm' dimensions. A 0.5-pm thick parylene layer provides electrical insulation. The integrated device is deployed inside a silicone mock artery with a standard angioplasty balloon. The planar structure is plastically deformed to a tubular shape, resulting in dual helical coils with 50-60 nH each. These L-C tanks are used to wirelessly probe pressures at two points along a channel for flow-rate detection.Fluidic experiments that emulate a blockage in the mock artery demonstrate that the resonant impedance and phase provided by the LC-tanks to a separate transmitting coil shift by 5-40 MHz over flow-rate change of 150-300 mL/min. Pressure sensitivity is 273 ppm/Torr, which is >lOOx higher than past results.

This paper presents a fully integrated battery-free sensing system that uses a two-site wireless pressure measurement for the detection of arterial stenosis. The remotely powered system uses a backscatter-modulated passive-telemetry interface and transmits sensor as well as reference information to an external system. The monolithic process used to realize the system integrates a 3 m BiCMOS circuit with silicon-on-glass absolute pressure sensors and an on-chip antenna. The wireless sensor interface consumes 340 W and uses capacitance-to-frequency conversion for readout of the vacuum-sealed pressure transducers. The integrated device has a 200 m profile and a volume of 2 mm 3 . The system can sense a reduction in flow of 13%, corresponding to a differential pressure of 3 mmHg.[1675]Index Terms-Implantable sensor, monolithic integration, on-chip antenna, pressure sensor, wireless telemetry.

This paper presents an integrated circuit (IC) that merges integrated optical and temperature transducers, optical interface circuitry, and a near-field communication (NFC)-enabled digital, wireless readout for a fully passive implantable sensor platform to measure glucose in people with diabetes. A flip-chip mounted LED and monolithically integrated photodiodes serve as the transduction front-end to enable fluorescence readout. A wide-range programmable transimpedance amplifier adapts the sensor signals to the input of an 11-bit analog-to-digital converter digitizing the measurements. Measurement readout is enabled by means of wireless backscatter modulation to a remote NFC reader. The system is able to resolve current levels of less than 10 pA with a single fluorescent measurement energy consumption of less than 1 μJ. The wireless IC is fabricated in a 0.6-μm-CMOS process and utilizes a 13.56-MHz-based ISO15693 for passive wireless readout through a NFC interface. The IC is utilized as the core interface to a fluorescent, glucose transducer to enable a fully implantable sensor-based continuous glucose monitoring system.