Perforating the GORE® CARDIOFORM septal occluder and atrial septal defect occluder to gain access to the left atrium.

OBJECTIVE: Perforate the expanded polytetrafluoroethylene membrane of the GORE® CARDIOFORM Septal Occluder (GSO) and GORE® CARDIOFORM ASD Occluder (GCA) after implantation. BACKGROUND: Percutaneous transseptal access to the left atrium is necessary for many structural and electrophysiological procedures. The potential need to access the left atrium may influence decision-making for patent foramen ovale or atrial septal defect closure. METHODS: Sixteen canines underwent implantation of equal number GSO or GCA devices. A transseptal crossing procedure was performed through the device 85 (±1) days postoccluder implantation. The crossing procedure was performed utilizing commercially available equipment: radiofrequency/SureFlex sheath and standard needle/Mullin's sheath. Progressive dilation of the perforation was performed to allow passage of a 12 French Mullin's sheath into the left atrium. RESULTS: Left atrial access was achieved in all cases. Postmortem analysis demonstrated passage through both occluder discs in all radiofrequency/SureFlex sheath cases (4 GSO, 4 GCA) and half of the standard needle/Mullin's sheath cases (3 GSO, 1 GCA). The remaining standard needle/Mullin's sheath cases demonstrated perforation through the right atrial disc but passage around the septal aspect of the left atrial disc, thus not perforating the left atrial disc. No acute embolic complications from the procedure were observed. CONCLUSIONS: Left atrial access may be achieved through the GSO or GCA devices after implantation and endothelialization. The combination of a radiofrequency needle and steerable sheath provides benefit over a standard needle and Mullin's sheath in accomplishing passage through both occluder discs.

BioMonitor 2 in-office setting insertion safety and feasibility evaluation with device functionality assessment: results from the prospective cohort BioInsight study.

BACKGROUND: Insertable cardiac monitors are utilized for the diagnosis of arrhythmias and traditionally have been inserted within hospitals. Recent code updates allow for reimbursement of office-based insertions; however, there is limited information regarding the resources and processes required to support in-office insertions. We sought to determine the safety and feasibility of in-office insertion of the BioMonitor 2 and better understand in-office procedures, including patient selection, pre-insertion protocols, resource availability, and staff support. METHODS: Patients meeting an indication for a rhythm monitor were prospectively enrolled into this single-arm, non-randomized trial. All patients underwent insertion in an office setting. Two follow-up visits at days 7 and 90 were required. Information on adverse events, device performance, office site preparations, and resource utilization were collected. RESULTS: Eighty-two patients were enrolled at six sites. Insertion was successful in all 77 patients with an attempt. Oral anticoagulation was stopped in 20.8% of patients and continued through insertion in 23.4%, while prophylactic antibiotics were infrequently utilized (37.7% of study participants). On average, the procedure required a surgeon plus two support staff and 35 min in an office room to complete the 8.4 min insertion procedure. The mean R-wave amplitude was 0.77 mV at insertion and 0.67 mV at 90-days with low noise burden (2.7%). There were no procedure related complications. Two adverse events were reported (event rate 2.7% [95% CI 0.3, 9.5%]). CONCLUSIONS: In-office insertion of the BioMonitor 2 is safe and feasible. Devices performed well with high R-wave amplitudes and low noise burden. These results further support shifting cardiac monitor insertions to office-based locations. TRIAL REGISTRATION: clinicaltrials.gov, NCT02756338. Registered 29 April 2016.

The promise of electrochemical impedance spectroscopy as novel technology for the management of patients with diabetes mellitus.

Self-monitoring of blood glucose is the standard of care in management of hyperglycemia among patients with diabetes mellitus. To increase the sensitivity and specificity of current devices, a novel method of detecting glucose using electrochemical impedance spectroscopy (EIS) technology is explored. The enzyme glucose oxidase (GOx) was fixed to gold electrodes and a sine wave of sweeping frequencies was induced using a wide range of concentrations of glucose. Each frequency in the impedance sweep was analyzed for the highest response and R-squared value. The frequency with both factors optimized is specific for the glucose-GOx binding interaction and was determined to be 1.17 kHz in purified solutions in both higher and lower ranges of glucose. The correlation between the impedance response and concentration at the low range of detection (0-100 mg dL(-1) of glucose) was determined to be 3.53 ohm/ln (mg dL(-1)) with an R-squared value of 0.90 with a 39 mg dL(-1) lower limit of detection. The same frequency of 1.17 kHz was verified in whole blood under the same glucose range. The above data confirm that EIS offers a new method of glucose detection as an alternative to current technology in use by patients. Additionally, the unique frequency response of individual markers allows for modulation of signals so that several other markers important in the management of diabetes could be measured with a single sensor.

Feasibility of Commercially Marketed Health Devices for Potential Clinical Application.

Concerns have been raised regarding the lack of validation on consumer-marketed health-monitoring devices. An investigation to characterize current health monitoring devices was carried out in the laboratory using widely accepted clinical and industry criteria. In total, 16 unique devices were examined. These devices were assessed according to their sensing modalities: step count, blood pressure, body temperature, electrocardiogram, blood oxygen saturation, and respiratory rate. Devices were tested at rest and immediately following exercise. Our results revealed that only four devices meet target requirements for accuracy. The AliveCor, a portable ECG monitor, accurately detected the heart rate for 87% of all recordings. To meet the target criterion for accuracy, the heart rate must be within ± 5 beats/minute or 10% of the standard measurement, whichever is lower. The Withings Pulse Ox, the Tinké, and the Santamedical SM-110 measured blood oxygen saturation with 2.1, 2.6, and 1.4 root-mean-square (rms) error, respectively. For blood oxygen saturation, the device should demonstrate rms error of < 3%. However, the Withings Pulse Ox and the Tinké failed to meet the accuracy criteria for their alternative biosensing capabilities: step count and respiratory rate, respectively. We conclude that the use of consumer-marketed health-monitoring devices for clinical or medical purposes should be undertaken with caution, especially in the absence of FDA or comparable clearance.

Detection of 1,5-Anhydroglucitol by Electrochemical Impedance Spectroscopy.

Multiple markers are used to assess glycemic control in patients with diabetes mellitus (DM). New technology that permits simultaneous detection of multiple biomarkers combined with those used at the point of care indicative of glycemic control, including glycemic variability determined from 1,5-anhydroglucitol measurement, could provide better management and further insight into the disease. This platform was based on previous research involving glucose detection and uses electrochemical impedance spectroscopy to detect a range of 1,5-anhydroglucitol concentrations at an optimal binding frequency. The enzyme pyranose oxidase was fixed to gold electrodes while a sine wave of sweeping frequencies was induced in purified solutions and in variable presence of whole blood. The optimal binding frequency for the detection of 1,5-anhydroglucitol was found to be 3.71 kHz. The impedance response compared to the concentration of target present was found to have a logarithmic slope of 7.04 with an R-squared value of 0.96. This response includes 2 experimental sets, a single test of a low concentration range and a high concentration range with 5 replicates. The relative standard deviation of the high range varied from 28% to 27% from lowest to highest concentrations. Best detection in complex solutions was found in lower blood concentrations of 0.5% and 1%, but maintained relatively high accuracy in concentrations 5% and 10%. The sensor platform was successfully evaluated at a high dynamic range of 1,5-AG in purified solutions. In the presence of whole blood, lowest percentages yielded the best results indicating that filtering interferents may be necessary in final device architecture.

A Disposable Tear Glucose Biosensor-Part 4: Preliminary Animal Model Study Assessing Efficacy, Safety, and Feasibility.

OBJECTIVE: A prototype tear glucose (TG) sensor was tested in New Zealand white rabbits to assess eye irritation, blood glucose (BG) and TG lag time, and correlation with BG. METHODS: A total of 4 animals were used. Eye irritation was monitored by Lissamine green dye and analyzed using image analysis software. Lag time was correlated with an oral glucose load while recording TG and BG readings. Correlation between TG and BG were plotted against one another to form a correlation diagram, using a Yellow Springs Instrument (YSI) and self-monitoring of blood glucose as the reference measurements. Finally, TG levels were calculated using analytically derived expressions. RESULTS: From repeated testing carried over the course of 12 months, little to no eye irritation was detected. TG fluctuations over time visually appeared to trace the same pattern as BG with an average lag times of 13 minutes. TG levels calculated from the device current measurements ranged from 4 to 20 mg/dL and correlated linearly with BG levels of 75-160 mg/dL (TG = 0.1723 BG = 7.9448 mg/dL; R2 = .7544). CONCLUSION: The first steps were taken toward preliminary development of a sensor for self-monitoring of tear glucose (SMTG). No conjunctival irritation in any of the animals was noted. Lag time between TG and BG was found to be noticeable, but a quantitative modeling to correlate lag time in this study is unnecessary. Measured currents from the sensors and the calculated TG showed promising correlation to BG levels. Previous analytical bench marking showed BG and TG levels consistent with other literature.