Following a Folding Transition with Capillary Electrophoresis and Ion Mobility Spectrometry.

Ion mobility spectrometry (IMS) is increasingly used to describe solution-phase phenomena and has recently been used to establish the presence of multiple intermediates during the folding of a model polypeptide, polyproline. These observations, however, are made on gas-phase structures. Capillary electrophoresis (CE) is a complementary solution-phase technique, also based on the separation of charged species as a function of size and charge. Here, both ion mobility and capillary electrophoresis are used to follow the folding transition of a 13-mer polyproline peptide from the all-cis polyproline I (PPI) conformation to the all-trans polyproline II (PPII) conformation upon immersion in aqueous solvent. Synchronous folding processes are observed using both techniques. Eight conformers are observed using ion mobility. Although only five peaks are observed using capillary electrophoresis, these peaks can be modeled as sums of the observed IMS conformers; this is strong evidence that ion mobility is sampling solution-phase structures. CE measurements provide the first direct evidence that multiple folding intermediates are present in solution.

Clinical experience with the Bendit steerable microcatheter: a new paradigm for endovascular treatment.

BACKGROUND: Vessel tortuosity poses a challenge during endovascular treatment of neurovascular lesions. Bendit Technologies (Petah Tikva, Israel) has developed flexible, steerable microcatheters designed with unique bending and torquing capabilities. OBJECTIVE: To describe our first-in-human trial of Bendit21. METHODS: Bendit21 was used in our exploratory, prospective, multicenter, open-label, single-arm clinical study, and in two compassionate use cases. Procedures were conducted at four centers in Austria, Germany, Israel, and the United States between May 2021 and March 2022, in patients with neurovascular conditions. The primary endpoints were device-related safety events, successful navigation through the neurovasculature, and, when intended, successful delivery of contrast or therapy. RESULTS: Two patients with giant aneurysms were treated successfully under compassionate use approval. The clinical study included 25 patients (mean age: 63.4±11.8 years; 32.0% female). Fourteen patients (56.0%) had aneurysms, two had arteriovenous malformations/fistulas (8.0%), one had a stroke (4.0%), four (16.0%) had intracranial stenosis, and four (16.0%) had other conditions. Bendit21 was used without a guidewire in 12/25 (48.0%) procedures. Bendit21 was successfully navigated through the vasculature without delays or spasms in all cases (100%). Contrast was delivered as intended in 7/7 (100%) cases. Therapeutic devices were delivered successfully with Bendit as intended in 14/18 (77.8%) cases; four deficiencies occurred in three patients with aneurysms, in whom delivery of coils, an intrasaccular device, or a flow diverter was attempted. There were no device-related safety events or mortalities. CONCLUSIONS: Our initial clinical experience with the Bendit21 microcatheter demonstrates its usefulness in achieving technical success in patients with challenging neurovascular conditions.

What the Baby Formula and Medical Contrast Material Shortages Have in Common: Insights and Recommendations for Managing the Iodinated Contrast Media Shortage.

The impact of supply chain and supply chain logistics, including personnel directly and indirectly related to the movement of supplies, has come to light in a variety of industries since the global COVID-19 pandemic. Acutely, the experience with baby formula and iodinated contrast material exposes key vulnerabilities to supply chains. The rather sudden diminished availability of iodinated contrast material has forced health care systems to engage in more judicious use of product through catalyzing the adoption of behaviors that had been recommended and deemed reasonable prior to the shortage. The authors describe efforts at a large, academic safety net county health system to conserve iodinated contrast media by optimizing contrast media use in the CT department and changing ordering patterns of referring providers. Special attention is given to opportunities to conserve contrast material in cardiothoracic imaging, including low kV and dual-energy CT techniques. A values-based leadership philosophy and collaboration with key stakeholders facilitate effective response to the critical shortage and rapid deployment of iodinated contrast media conservation strategies. Last, while the single-supplier model is efficient and cost-effective, its application to critically necessary services such as health care must be questioned considering disruptions related to the COVID-19 pandemic. Keywords: CT, Intravenous Contrast Agents, CT-Spectral Imaging (Dual Energy) ©RSNA, 2022.

Does endovascular therapy change outcomes in nonagenarians with acute ischemic stroke?

BACKGROUND: Ischemic strokes can be devastating for elderly patients, and randomized control trials of mechanical thrombectomy have shown encouraging results. We present the first analysis of clinical outcomes in nonagenarians with acute ischemic stroke treated with best medical therapy compared to endovascular revascularization therapy. METHODS: A retrospective analysis was performed on 42 patients 90 years or older who were treated for acute ischemic stroke. Modified Rankin scores were calculated immediately post-injury, at discharge, and at 30 days and 90 days following discharge. Student's t-test and Wald tests were performed to evaluate whether endovascular treatment was associated with modified Rankin Score improvement at discharge, 30 days, or 90 days after discharge. RESULTS: Follow-up data were available for 32/42 (76%) and 20/42 (48%) patients at 30 and 90 days after discharge, respectively. 8/9 (89%) patients who underwent endovascular treatment reached Thrombolysis in Cerebral Infarction scale 2b or better with no procedural complications. 12/42 (29%) patients, including four who underwent endovascular treatment, were discharged to hospice or deceased. No significant differences in modified Rankin Score improvement were observed between the endovascular and medical management groups at discharge (p = 0.96), at 30 days (p = 0.63), or at 90 days (p = 0.96). CONCLUSIONS: Our analysis shows that revascularization therapy is a safe treatment, but it was not associated with improved functional status in nonagenarians with acute ischemic stroke. Endovascular therapy shows promise, and larger prospective studies are necessary to assess the benefits of revascularization therapy in the elderly population.

The evidentiary basis of vertebral augmentation: a 2019 update.

No aspect of neurointerventional practice has been associated with as longstanding contention and debate as to its effectiveness as has vertebroplasty (VP). Four blinded randomized controlled trials published since 2009 have demonstrated conflicting results regarding a conferred benefit in pain reduction and functional improvement for patients who undergo VP for osteoporotic vertebral compression fractures. Significant heterogeneity exists between each of these trials, which has resulted in difficulty for interventionalists and surgeons to translate the trial findings into routine clinical practice. In addition, patients and their families are ever more enlightened and enabled via the internet and social media to review both medical literature and websites. Without the proper background and context, their decisions may be lacking appropriate and necessary scientific discussion. This review article summarizes the randomized controlled trial data to date, with particular focus on the aforementioned four blinded studies. We will also evaluate the profound impact of the decrease in vertebral augmentation utilization on short- and long-term patient morbidity and mortality using available national and administrative datasets from both within the USA and internationally. We also consider future trial design to help evaluate this procedure and determine its role in modern neurointerventional practice.

Analysis of vertebral augmentation practice patterns: a 2016 update.

OBJECTIVE: To evaluate procedure utilization patterns for vertebroplasty and kyphoplasty in the US Medicare population from 2004 to 2014. METHODS: The analysis was performed using the Centers for Medicare and Medicaid Services database of specialty utilization files for the fee for service (FFS) Medicare population. RESULTS: The FFS Medicare population increased by 28% with an annual increase of 2.5% from 2004 to 2014. Utilization of vertebroplasty procedures decreased by 63% with an average annual decrease of 9.5% from 2004 to 2014 per 100 000 FFS Medicare beneficiaries. During the same time period, kyphoplasty procedures decreased by a total of 10%, with an average annual decrease of 1.3%. For augmentation generally (combined vertebroplasty/kyphoplasty data) there was thus an overall decrease in the rate per 100 000 Medicare population of 32% from 2004 to 2014, with an average annual decrease of 4.8%. The majority of vertebroplasty procedures were performed by radiologists whereas the majority of kyphoplasties were performed by orthopedic surgeons and neurosurgeons. CONCLUSIONS: There has been a significant decline in vertebroplasty and kyphoplasty procedures in the FFS Medicare population between 2004 and 2014.

Hydrogel-coated coils for the treatment of cerebral aneurysms: preliminary results.

OBJECT: The authors present a retrospective analysis of their initial experience with the recently developed MicroVention HydroCoil to treat patients with cerebral aneurysms. Unlike the bare metal coils initially available for endovascular treatment of aneurysms, HydroCoils have a layer of hydrogel polymer surrounding a platinum metallic core. The hydrogel polymer expands soon after making contact with blood. The expanded hydrogel polymer provides increased volumetric filling compared with bare metal coils and offers a more biocompatible surface, as demonstrated in animal models. METHODS: Over a 17-month period, the authors used HydroCoils to treat 30 patients with 33 aneurysms. All patients had been treated at least 6 months prior to data analysis. Initial treatment results as well as records of clinical and angiographic follow up were reviewed. Six-month posttreatment angiograms were available for 25 patients. CONCLUSIONS: The HydroCoils were implanted with few complications. On angiographic follow up, a clearly defined radiolucent separation of the coils from the parent artery was noted in many of the aneurysms treated. The authors have not previously observed angiographically demonstrated lucencies separating the coils from the parent artery. This frequent, but not consistent, appearance on follow-up angiograms obtained in this study indicates that HydroCoils support significant neointimal formation across the neck of treated aneurysms. The preliminary results indicate that HydroCoils can be used safely and effectively to treat aneurysms and that these devices may allow for improved aneurysm filling.