Status Update and Interim Results from the Asymptomatic Carotid Surgery Trial-2 (ACST-2)

Objectives: ACST-2 is currently the largest trial ever conducted to compare carotid artery stenting (CAS) with carotid endarterectomy (CEA) in patients with severe asymptomatic carotid stenosis requiring revascularization. Methods: Patients are entered into ACST-2 when revascularization is felt to be clearly indicated, when CEA and CAS are both possible, but where there is substantial uncertainty as to which is most appropriate. Trial surgeons and interventionalists are expected to use their usual techniques and CE-approved devices. We report baseline characteristics and blinded combined interim results for 30-day mortality and major morbidity for 986 patients in the ongoing trial up to September 2012. Results: A total of 986 patients (687 men, 299 women), mean age 68.7 years (SD ± 8.1) were randomized equally to CEA or CAS. Most (96%) had ipsilateral stenosis of 70-99% (median 80%) with contralateral stenoses of 50-99% in 30% and contralateral occlusion in 8%. Patients were on appropriate medical treatment. For 691 patients undergoing intervention with at least 1-month follow-up and Rankin scoring at 6 months for any stroke, the overall serious cardiovascular event rate of periprocedural (within 30 days) disabling stroke, fatal myocardial infarction, and death at 30 days was 1.0%. Conclusions: Early ACST-2 results suggest contemporary carotid intervention for asymptomatic stenosis has a low risk of serious morbidity and mortality, on par with other recent trials. The trial continues to recruit, to monitor periprocedural events and all types of stroke, aiming to randomize up to 5,000 patients to determine any differential outcomes between interventions. Clinical trial: ISRCTN21144362. © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved

Second asymptomatic carotid surgery trial (ACST-2): a randomised comparison of carotid artery stenting versus carotid endarterectomy

Background: Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence. Methods: ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362. Findings: Between Jan 15, 2008, and Dec 31, 2020, 3625 patients in 130 centres were randomly allocated, 1811 to CAS and 1814 to CEA, with good compliance, good medical therapy and a mean 5 years of follow-up. Overall, 1% had disabling stroke or death procedurally (15 allocated to CAS and 18 to CEA) and 2% had non-disabling procedural stroke (48 allocated to CAS and 29 to CEA). Kaplan-Meier estimates of 5-year non-procedural stroke were 2·5% in each group for fatal or disabling stroke, and 5·3% with CAS versus 4·5% with CEA for any stroke (rate ratio [RR] 1·16, 95% CI 0·86–1·57; p=0·33). Combining RRs for any non-procedural stroke in all CAS versus CEA trials, the RR was similar in symptomatic and asymptomatic patients (overall RR 1·11, 95% CI 0·91–1·32; p=0·21). Interpretation: Serious complications are similarly uncommon after competent CAS and CEA, and the long-term effects of these two carotid artery procedures on fatal or disabling stroke are comparable. Funding: UK Medical Research Council and Health Technology Assessment Programme

Bidirectional Influences of Information-Sampling and Concept Learning

Contemporary models of categorization typically tend to sidestep the problem of how information is initially encoded during decision-making. Instead, a focus of this work has been to investigate how, through selective attention, stimulus representations are “contorted” such that behaviourally-relevant dimensions are accentuated (or “stretched”), and representations of irrelevant dimensions are ignored (or “compressed”). In high-dimensional real-world environments, it is computationally infeasible to sample all available information, and human decision-makers selectively sample information from sources expected to provide relevant information. To address these and other shortcomings, we develop an active sampling model, Sampling Emergent Attention (SEA), which sequentially and strategically samples information sources until the expected cost of information exceeds the expected benefit. The model specifies the interplay of two components, one involved in determining the expected utility of different information sources and the other in representing knowledge and beliefs about the environment. These two components interact such that knowledge of the world guides information sampling, and what is sampled updates knowledge. Like human decision-makers, the model displays strategic sampling behaviour, such as terminating information search when sufficient information has been sampled and adaptively adjusting the search path in response to previously sampled information. The model also shows human-like failure modes. For example, when information exploitation is prioritized over exploration, the bidirectional influences between information-sampling and learning can lead to the development of beliefs that systematically differ from reality

Using C-14, C-13, O-18 and O-17 isotopic variations to provide insights into the high northern latitude surface CO inventory

Measurements of the complete isotopic composition of atmospheric CO ((CO)-C-13, (CO)-C-14, (CO)-O-17, (CO)-O-18) have been carried out at the high northern latitude stations Spitsbergen, Norway, and Alert, Canada. The annual changes of the isotope signatures reflect the seasonally varying contributions from the individual CO sources and the OH sink. Short-term variability is small at the remote sampling locations. Nevertheless, the interannual variability is considerable, in particular for the summer minimum. The most prominent event was a strong increase in CO in 1998 that persisted for several months. Using the isotope signatures it is possible to clearly identify extraordinarily strong biomass burning during that season as the cause for this large-scale CO anomaly. In 1997, on the other hand, biomass burning emissions were very low, leading to an unusually low summer minimum and corresponding isotope signatures. The results underscore that monitoring of CO and its isotopic composition at remote high latitude stations is a valuable tool to better understand long- term variations of CO that are representative for the whole high northern latitude region

Using C-14, C-13, O-18 and O-17 isotopic variations to provide insights into the high northern latitude surface CO inventory

Measurements of the complete isotopic composition of atmospheric CO ((CO)-C-13, (CO)-C-14, (CO)-O-17, (CO)-O-18) have been carried out at the high northern latitude stations Spitsbergen, Norway, and Alert, Canada. The annual changes of the isotope signatures reflect the seasonally varying contributions from the individual CO sources and the OH sink. Short-term variability is small at the remote sampling locations. Nevertheless, the interannual variability is considerable, in particular for the summer minimum. The most prominent event was a strong increase in CO in 1998 that persisted for several months. Using the isotope signatures it is possible to clearly identify extraordinarily strong biomass burning during that season as the cause for this large-scale CO anomaly. In 1997, on the other hand, biomass burning emissions were very low, leading to an unusually low summer minimum and corresponding isotope signatures. The results underscore that monitoring of CO and its isotopic composition at remote high latitude stations is a valuable tool to better understand long- term variations of CO that are representative for the whole high northern latitude region

Tele-Untethered: Telemedicine Without Waiting Rooms

Background and objectivesTelemedicine bridges the gap between care needs and provider availability. The value of telemedicine can be eclipsed by long wait times, especially if patients are stuck in virtual waiting rooms. UCSD Tele-Untethered allows patients to join visits without waiting in virtual waiting rooms. Tele-Untethered uses a text-to-video link to improve clinic flow, decrease virtual waiting room reliance, improve throughput, and potentially improve satisfaction.MethodsThis institutional review board (IRB)-approved quality improvement pilot (IRB #210364QI) included patients seen in a single vascular neurology clinic, within the pilot period, if they had a smartphone/cell phone, and agreed to participate in a flexible approach to telehealth visits. Standard work was disseminated (patient instructions, scripting, and workflows). Patients provided a cell phone number to receive a text link when the provider was ready to see them. Metrics included demographics, volumes, visit rates, percentage seen early/late, time savings, and satisfaction surveys.ResultsOver 2.5 months, 22 patients were scheduled. Of those arriving, 76% were "Tele-Untethered" and 24% were "Standard Telemedicine." Text-for-video link was used for 94% of Tele-Untethered. Fifty-five percent were seen early. There was a 55-minute-per-session time savings.ConclusionThis UCSD Tele-Untethered pilot benefitted patients by allowing scheduling flexibility while not being tied to a "virtual waiting room." It benefited providers as it allowed them to see patients in order/not tied to exact times, improved throughput, and saved time. Even modest time savings for busy providers, coupled with Lean workflows, can provide critical value. High Tele-Untethered uptake and use of verbal check-in highlight that patients expect flexibility and ease of use. As our initial UCSD Tele-Untethered successes included patient flexibility and time savings for patients and providers, it can serve as a model as enterprises strive for optimal care and improved satisfaction. Expansion to other clinic settings is underway with a mantra of "UCSD Tele-Untethered: Your provider can see you now.