Adamson, Teagan

AbstractObjectivePerforate the expanded polytetrafluoroethylene membrane of the GORE® CARDIOFORM Septal Occluder (GSO) and GORE® CARDIOFORM ASD Occluder (GCA) after implantation.BackgroundPercutaneous 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.MethodsSixteen 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.ResultsLeft 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.ConclusionsLeft 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.

Background: 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. Methods: 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. Results: 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%. Conclusions: 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.

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; R 2 = .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.