R-wave amplitude changes with posture and physical activity over time in an insertable cardiac monitor.

Background: Insertable cardiac monitors (ICMs) are accepted tools in cardiac arrhythmia management. Consistent R-wave amplitude (RWA) is essential for optimal detection. Objectives: Assess RWAs with posture/activities at insertion and at 30 days. Methods: Participants (n = 90) with Confirm Rx™ ICM had RWAs measured in different postures (supine, right-side [RS], left-side [LS], sitting, and standing) and defined physical activities (including isometric push [IPUSH] and pull) at 2 time points. ICMs were inserted in 45° to sternum and parasternal orientations. Results: There were significant reductions at insertion with RS, LS, sitting, or standing vs supine (reference position) (all P < .05). At 30 days, significant changes only occurred with LS and sitting (P < .05). Sex had an effect on RWAs, with females having significant variability at insertion (supine vs RS, LS, sitting, standing, and IPUSH; all P < .05). Males showed large RWA interpatient variabilities but minimal differences between positions vs supine. At 30 days, RS, LS, and sitting positions remained significant for females (P < .05), while in males RWAs were higher than at insertion for most postures and activities. The orientation 45° to sternum had consistently higher RWAs vs parasternal orientation at both time points (P < .0001). In females, ICM orientation had no significant effect on RWAs; however, in males the 45° to sternum produced higher RWAs. ICM movement from the insertion site showed no correlation with RWA changes. Conclusion: The mean RWAs were higher at 30 days with less interparticipant and interpostural variability; males had higher RWAs compared to females; 45° to sternum orientation had higher RWAs; and ICM migration from the insertion site did not affect RWAs.

Usability and Robustness of the Wixela Inhub Dry Powder Inhaler.

Background: Wixela Inhub is a generic version of Advair Diskus recently approved by the U.S. Food and Drug Administration. The Inhub inhaler delivers fluticasone propionate (FP)/salmeterol in a dry powder formulation. The goals of our studies were to demonstrate that the Inhub inhaler can be used by representative end users and confirm the robustness of the Inhub inhaler. Methods: Study 1: A nondosing usability assessment, the device orientation study, confirmed that intended users (represented by patients diagnosed with asthma or chronic obstructive pulmonary disease [COPD] who were naive to dry powder inhalers and current Advair Diskus users) could use the Inhub inhaler safely and effectively. Subjects were provided with an Inhub inhaler in commercial packaging, including instructions for use, and were asked to undertake three dose simulations using the inhaler. Subjects were encouraged to interact with this new drug delivery device as they would at home. Subjects were not provided with training on the use of the device. Subjects were observed interacting with the Inhub inhaler, and those who currently use Diskus were also observed interacting with the Diskus to determine whether their mental model of the use of Diskus impacted their interaction with the Inhub device, this assessment was not a primary outcome of the study. Study 2: This is an open-label clinical study to confirm the robustness of the Inhub inhaler after at home patient use. Subjects diagnosed with asthma or COPD were provided Inhub inhaler training and subsequently self-administered 3 weeks of twice daily doses of Wixela Inhub 250 µg FP/50 µg salmeterol in the home environment. The Inhub inhalers were returned to the investigator after ∼3 weeks of outpatient use for in vitro tests on the drug remaining in each inhaler. Results: Study 1 enrolled 110 subjects, and all completed the study. Most subjects (100/110) held the Inhub inhaler in the correct orientation and of those who did not, 9 still achieved a peak inhalation flow rate of ≥30 L/min and a total inhaled volume of ≥1 L, thus meeting the requirements of the study success criteria. In Study 2, 111 pediatric, adult, and elderly subjects with asthma or COPD received the study drug. After ∼3 weeks of outpatient use of the Inhub inhaler by subjects, comprehensive in vitro testing demonstrated that the FP and salmeterol pharmaceutical performance in the Inhub inhaler was preserved. Conclusions: The majority of subjects demonstrated safe and effective use of the Inhub inhaler. In vitro testing and inspections confirmed the robustness of the Inhub inhaler after outpatient use. Clinical trial registration number: NCT02474017.

Impact of Insertion Technique and Iliac Artery Anatomy on Fenestrated Endovascular Aneurysm Repair.

Purpose: To develop a mechanically realistic aortoiliac model to evaluate anatomic variables associated with stent-graft rotation and to assess common deployment techniques that may contribute to rotation. Materials and Methods: Idealized aortoiliac geometries were constructed either through direct 3-dimensional (3D) printing (rigid) or through casting with polyvinyl alcohol using 3D-printed molds (flexible). Flexible model bending rigidity was controlled by altering wall thickness. Three flexible patient-specific models were also created based on the preoperative computed tomography angiograms. Zenith infrarenal and fenestrated devices were used in this study. The models were pressurized to 100 mm Hg with normal saline. Deployments were performed under fluoroscopy at 37°C. Rotation was calculated by tracking the change in position of gold markers affixed to the devices. Results: In the rigid idealized models, stent-graft rotation increased with increasing torsion; torsion levels of 1.6, 2.6, and 3.6 mm-1 had mean rotations of 5.2°±0.03°, 11.2°±4.8°, and 27.6°±13.0°, respectively (p<0.001). In the flexible models, the highest rotation (58°±3.0°) was observed in models with high torsion and high rigidity (7.5 mm-1 net torsion and 254 N·m2 flexural rigidity). No rotation was observed in the absence of torsion. Applying torque to the device during insertion significantly increased stent-graft rotation by an average of 28° across all levels of torsion (p<0.01). Multiple device insertions prior to deployment did not change the observed device rotation. The patient-specific models accurately predicted the degree of rotation seen intraoperatively to within 5°. Conclusion: Insertion technique plays an important role in the degree of stent-graft rotation during deployment. Our model suggests that in vivo correction of device orientation can increase the observed rotation and supports the concept of fully removing the device, adjusting the orientation, and subsequently reinserting. Additionally, increasing iliac artery torsion in the presence of increased vessel rigidity results in stent-graft rotation.