Not seeing the forest for the trees: combination of path integration and landmark cues in human virtual navigation.

Introduction: In order to successfully move from place to place, our brain often combines sensory inputs from various sources by dynamically weighting spatial cues according to their reliability and relevance for a given task. Two of the most important cues in navigation are the spatial arrangement of landmarks in the environment, and the continuous path integration of travelled distances and changes in direction. Several studies have shown that Bayesian integration of cues provides a good explanation for navigation in environments dominated by small numbers of easily identifiable landmarks. However, it remains largely unclear how cues are combined in more complex environments. Methods: To investigate how humans process and combine landmarks and path integration in complex environments, we conducted a series of triangle completion experiments in virtual reality, in which we varied the number of landmarks from an open steppe to a dense forest, thus going beyond the spatially simple environments that have been studied in the past. We analysed spatial behaviour at both the population and individual level with linear regression models and developed a computational model, based on maximum likelihood estimation (MLE), to infer the underlying combination of cues. Results: Overall homing performance was optimal in an environment containing three landmarks arranged around the goal location. With more than three landmarks, individual differences between participants in the use of cues are striking. For some, the addition of landmarks does not worsen their performance, whereas for others it seems to impair their use of landmark information. Discussion: It appears that navigation success in complex environments depends on the ability to identify the correct clearing around the goal location, suggesting that some participants may not be able to see the forest for the trees.

The Clinical Impact of Access Site Selection for Successful Thrombolysis and Intervention in Acute Critical Lower Limb Ischaemia (RAD-ALI Registry).

Background: Acute limb ischaemia (ALI) is of great clinical importance due to its consequent serious complications and high comorbidity and mortality rates. The purpose of this study was to compare the acute success and complication rates of CDT performed via transradial, transbrachial, and transfemoral access sites in patients with acute lower limb vascular occlusion and to investigate the 1-year outcomes of CDT and MT for ALI. Methods: Between 2008 and 2019, 84 consecutive patients with ALI were treated with CDT in a large community hospital. Data were collected and retrospectively analysed. The primary ("safety") endpoints encompassed major adverse events (MAEs), major adverse limb events (MALEs), and the occurrence of complications related to the access site. Secondary ("efficacy") endpoints included both technical and clinical achievements, treatment success, fluoroscopy time, radiation dose, procedure time, and the crossover rate to an alternative puncture site. Results: CDT was started with radial (n = 17), brachial (n = 9), or femoral (n = 58) access. CDT was technically successful in 74/84 patients (88%), but additional MT and angioplasty and/or stent implantation was necessary in 17 (20.2%) and 45 cases (53.6%), respectively. Clinical success was achieved in 74/84 cases (88%). The mortality rate at 1 year was 14.3%. The cumulative incidence of MAEs and MALEs at 12 months was 50% and 40.5%, respectively. After conducting multivariate analysis, history of Rutherford stage IIB (hazard ratio [HR], 3.64; 95% confidence interval [CI], 1.58-8.41; p = 0.0025), occlusion of the external iliac artery (HR, 27.52; 95% CI, 2.83-267.33; p = 0.0043), being a case of clinically unsuccessful thrombolysis (HR, 7.72; 95% CI, 2.48-23.10; p = 0.0004), and the presence of diabetes mellitus (HR, 2.18; 95% CI, 1.01-4.71; p = 0.047) were independent predictors of a high MAE mortality rate at 12 months. For MALEs, statistically significant differences were detected with the variables history of Rutherford stage IIB (HR, 4.30; 95% CI, 1.99-9.31; p = 0.0002) and external iliac artery occlusion (HR, 31.27; 95% CI, 3.47-282.23; p = 0.0022). Conclusions: Based on the short-term results of CDT, acute limb ischaemia can be successfully, safely, and effectively treated with catheter-directed thrombolytic therapy with radial, brachial, or femoral access. However, radial access is associated with fewer access site complications. A history of Rutherford stage IIB, occlusion of external iliac artery, unsuccessful thrombolysis, and the presence of diabetes mellitus were independently associated with an increased risk of MAEs. A history of Rutherford stage IIB and external iliac artery occlusion are independent predictors of MALEs.

Ten-Year Outcome of Recanalization or Medical Therapy for Concomitant Chronic Total Occlusion After Myocardial Infarction.

BACKGROUND: The EXPLORE (Evaluating Xience and Left Ventricular Function in PCI on Occlusions After STEMI) trial was the first and only randomized trial investigating chronic total occlusion (CTO) percutaneous coronary intervention (PCI) early after primary PCI for ST-segment-elevation myocardial infarction, compared with medical therapy for the CTO. We performed a 10-year follow-up of EXPLORE to investigate long-term safety and clinical impact of CTO PCI after ST-segment-elevation myocardial infarction, compared with no-CTO PCI. METHODS AND RESULTS: In EXPLORE, 302 patients post-ST-segment-elevation myocardial infarction with concurrent CTO were randomized to CTO PCI within ≈1 week or no-CTO PCI. We performed an extended clinical follow-up for the primary end point of major adverse cardiac events, consisting of cardiovascular death, coronary artery bypass grafting, or myocardial infarction. Secondary end points included all-cause death, angina, and dyspnea. Median follow-up was 10 years (interquartile range, 8-11 years). The primary end point occurred in 25% of patients with CTO PCI and in 24% of patients with no-CTO PCI (hazard ratio [HR], 1.11 [95% CI, 0.70-1.76]). Cardiovascular mortality was higher in the CTO PCI group (HR, 2.09 [95% CI, 1.10-2.50]), but all-cause death was similar (HR, 1.53 [95% CI, 0.93-2.50]). Dyspnea relief was more frequent after CTO PCI (83% versus 65%, P=0.005), with no significant difference in angina. CONCLUSIONS: This 10-year follow-up of patients post-ST-segment-elevation myocardial infarction randomized to CTO PCI or no-CTO PCI demonstrated no clinical benefit of CTO PCI in major adverse cardiac events or overall mortality. However, CTO PCI was associated with a higher cardiovascular mortality compared with no-CTO PCI. Our long-term data support a careful weighing of effective symptom relief against an elevated cardiovascular mortality risk in CTO PCI decisions. REGISTRATION: URL: https://www.trialregister.nl; Unique identifier: NTR1108.

Finding the gap: neuromorphic motion-vision in dense environments.

Animals have evolved mechanisms to travel safely and efficiently within different habitats. On a journey in dense terrains animals avoid collisions and cross narrow passages while controlling an overall course. Multiple hypotheses target how animals solve challenges faced during such travel. Here we show that a single mechanism enables safe and efficient travel. We developed a robot inspired by insects. It has remarkable capabilities to travel in dense terrain, avoiding collisions, crossing gaps and selecting safe passages. These capabilities are accomplished by a neuromorphic network steering the robot toward regions of low apparent motion. Our system leverages knowledge about vision processing and obstacle avoidance in insects. Our results demonstrate how insects might safely travel through diverse habitats. We anticipate our system to be a working hypothesis to study insects' travels in dense terrains. Furthermore, it illustrates that we can design novel hardware systems by understanding the underlying mechanisms driving behaviour.

The Virtual Navigation Toolbox: Providing tools for virtual navigation experiments.

Spatial navigation research in humans increasingly relies on experiments using virtual reality (VR) tools, which allow for the creation of highly flexible, and immersive study environments, that can react to participant interaction in real time. Despite the popularity of VR, tools simplifying the creation and data management of such experiments are rare and often restricted to a specific scope-limiting usability and comparability. To overcome those limitations, we introduce the Virtual Navigation Toolbox (VNT), a collection of interchangeable and independent tools for the development of spatial navigation VR experiments using the popular Unity game engine. The VNT's features are packaged in loosely coupled and reusable modules, facilitating convenient implementation of diverse experimental designs. Here, we depict how the VNT fulfils feature requirements of different VR environments and experiments, guiding through the implementation and execution of a showcase study using the toolbox. The presented showcase study reveals that homing performance in a classic triangle completion task is invariant to translation velocity of the participant's avatar, but highly sensitive to the number of landmarks. The VNT is freely available under a creative commons license, and we invite researchers to contribute, extending and improving tools using the provided repository.

There is an urgent need to adopt a pull-flow logic for the supply of RBCs to meet patients' needs: A single center study.

BACKGROUND: Despite major demographic changes, several decisions and initiatives, among which Patient Blood Management, have led to a significant reduction in the transfusion of packed red blood cells (RBCs) in Belgium, as it has been observed in many countries. Unfortunately, not all blood groups were proportionately impacted and shortage in O D-negative RBCs is regularly or chronically observed. The goal of this study was to examine how to optimize the use and the supply of O D-negative blood in our academic hospital. METHODOLOGY: All blood transfusions performed at Cliniques universitaires Saint-Luc between January 1, 2019 and December 31, 2021 were reviewed. The blood group of the patients was compared with the blood group of the RBCs actually supplied and transfused. RESULTS: 49.823 RBCs transfusions were analyzed. The patients' needs didn't reflect those of a Caucasian population, with an increase of O (47.9%) and B (10.3%) for the ABO blood group, and a quite high proportion of R0r (8.6%) for the Rh blood group. Only two thirds of O D-negative RBCs were transfused to O rr or R0r patients. CONCLUSION: The application of PBM and the ethnic imbalance between blood donor and patient populations are two important risk factors for chronic shortages of O D-negative blood. To adapt blood component resources, it is essential to have a complete picture of the real needs of patients according to their blood group profile. Blood donor centers must adapt to the evolving needs of hospitals in order to plan future supplies in a "pull-flow" approach.

No-reflow after primary percutaneous coronary intervention in patients with ST-elevation myocardial infarction: an angiographic core laboratory analysis of the TOTAL Trial.

BACKGROUND: The optimal strategy to prevent no-reflow in ST-elevation myocardial infarction (STEMI) patients undergoing percutaneous coronary intervention (PCI) is unknown. AIMS: We aimed to examine the effect of thrombectomy on the outcome of no-reflow in key subgroups and the adverse clinical outcomes associated with no-reflow. METHODS: We performed a post hoc analysis of the TOTAL Trial, a randomised trial of 10,732 patients comparing thrombectomy versus PCI alone. This analysis utilised the angiographic data of 1,800 randomly selected patients. RESULTS: No-reflow was diagnosed in 196 of 1,800 eligible patients (10.9%). No-reflow occurred in 95/891 (10.7%) patients randomised to thrombectomy compared with 101/909 (11.1%) in the PCI-alone arm (odds ratio [OR] 0.95, 95% confidence interval [CI]: 0.71-1.28; p-value=0.76). In the subgroup of patients who underwent direct stenting, those randomised to thrombectomy compared with PCI alone experienced less no-reflow (19/371 [5.1%] vs 21/216 [9.7%], OR 0.50, 95% CI: 0.26-0.96). In patients who did not undergo direct stenting, there was no difference between the groups (64/504 [12.7%] vs 75/686 [10.9%)], OR 1.18, 95% CI: 0.82-1.69; interaction p-value=0.02). No-reflow patients had a significantly increased risk of experiencing the primary composite outcome (cardiovascular death, recurrent myocardial infarction, cardiogenic shock, or NYHA Class IV heart failure) at 1 year (adjusted hazard ratio 1.70, 95% CI: 1.13-2.56; p-value=0.01). CONCLUSIONS: In patients with STEMI treated by PCI, thrombectomy did not reduce no-reflow in all patients but may be synergistic with direct stenting. No-reflow is associated with increased adverse clinical outcomes.

The potential underlying mechanisms during learning flights.

Hymenopterans, such as bees and wasps, have long fascinated researchers with their sinuous movements at novel locations. These movements, such as loops, arcs, or zigzags, serve to help insects learn their surroundings at important locations. They also allow the insects to explore and orient themselves in their environment. After they gained experience with their environment, the insects fly along optimized paths guided by several guidance strategies, such as path integration, local homing, and route-following, forming a navigational toolkit. Whereas the experienced insects combine these strategies efficiently, the naive insects need to learn about their surroundings and tune the navigational toolkit. We will see that the structure of the movements performed during the learning flights leverages the robustness of certain strategies within a given scale to tune other strategies which are more efficient at a larger scale. Thus, an insect can explore its environment incrementally without risking not finding back essential locations.

Superficial temporal artery access for carotid artery stenting: A case report.

Percutaneous intervention of patients who suffer from generalized vascular disease is often a great challenge due to the limited accessibility of the access gates. We discuss the case of a 66-year-old man who presented with critical right internal carotid artery (ICA) stenosis after previous hospitalization due to stroke. In addition to arteria lusoria, the patient had known bilateral femoral amputation, occlusion of the left ICA and significant three-vessel coronary artery disease. After unsuccessful common carotid artery (CCA) cannulation from the right distal radial artery access, we successfully performed the diagnostic angiography and the planned right ICA-CCA intervention using superficial temporal artery (STA) puncture. We showed that STA access can be used as an alternative and additional access site for diagnostic carotid artery angiography and intervention when standard access sites alone are insufficient.

Radial and ulnar approach for carotid artery stenting with Roadsaver™ double layer micromesh stent: Early and long-term follow-up.

AIMS: We aimed to evaluate the feasibility and safety of carotid artery stenting (CAS) with a newly designed double-layer micromesh stent using wrist approach in patients with significant carotid disease. MATERIALS AND METHODS: Between January 2016 and December 2021, 105 patients undergoing CAS with Roadsaver™ stent were enrolled in a single center prospective study. Follow-up assessments included neurological exams, duplex ultrasound (DUS), and 12-lead ECG. The primary endpoint was the 30-day composite rate of stroke, death, and myocardial infarction. Secondary endpoints included procedure success, access site complications, device success, target lesion revascularization, and in-stent restenosis evaluated with DUS. Long-term outcomes up to 72 months of follow-up were assessed in all eligible patients. RESULTS: The study population was predominantly male (69.5%) with a median age of 68 ± 8 years. Patients were symptomatic in 80% of the cases, and 35% fulfilled the high-risk criteria for surgical endarterectomy. The right internal carotid artery was the target artery in 56 (53.4%), and the left in 49 (46.6%) of the cases. All procedures were successfully completed from the right wrist, with right radial access in 94 (89.5%) cases and ulnar artery access with previous radial artery occlusion in 11 (10.5%) cases. All patients were treated successfully with the study device. The primary endpoint was met with a 30-day major adverse event rate of 0.9% (1/105). Up to 72 months of follow-up (median 30 ± 20 months) there were no strokes, neurological deaths, or target lesion revascularization of the treated lesion. Doppler ultrasound examination revealed nonsignificant in-stent restenosis in two asymptomatic patients. There was no hand ischemia detected in any patient. CONCLUSION: Results from this study demonstrate the radial and ulnar access for CAS with double layer micromesh Roadsaver™ stent is safe and feasible and associated with favorable early and long-term follow-up.

Distal Radial Artery Access for Recanalization of Radial Artery Occlusion and Repeat Intervention: A Single Center Experience.

Background: Once occluded, the radial artery becomes unsuitable for repeat interventions and obligates the need for alternative vascular access, such as the femoral approach, which is not encouraged by current guidelines. With the dissemination of distal radial access (DRA), which allows the cannulation of the artery in its distal segment and which remains patent even in the case of radial artery occlusion (RAO), the option to perform angioplasty at this level becomes feasible. Methods: Thirty patients with RAO were enrolled in this pilot study. Recanalization was performed through DRA using hydrophilic guidewires. The feasibility endpoint was procedural success, namely the successful RAO recanalization, the efficacy endpoint was patency of the artery at 30 days, and the safety endpoint was the absence of periprocedural vascular major complications or major adverse cardiac and cerebrovascular events. Results: The mean age of the patients was 63 ± 11 years, and 15 patients (50%) were men. Most patients had asymptomatic RAO (n = 28, 93.3%), and only two (6.6%) reported numbness in their hands. The most common indication for the procedure was PCI (19, 63.2%). Total procedural time was 41 ± 22 min, while the amount of contrast used was 140 ± 28 mL. Procedural success was 100% (n = 30). Moreover, there were no major vascular complications (0%); only two small hematomas were described (10%) and one had an angiographically visible perforation (3%). One case of periprocedural stroke was reported (3%), with onset immediately after the procedure and recovering 24 h later. Twenty-seven radial arteries (90%) remained patent at the one-month follow-up. Conclusions: RAO recanalization is feasible and safe, and by using dedicated hydrophilic guidewires, the success rate is high without significantly increasing procedural time or the amount of used contrast.

Distal vs Conventional Radial Access for Coronary Angiography and/or Intervention: A Meta-Analysis of Randomized Trials.

BACKGROUND: Emerging evidence from randomized clinical trials (RCTs) comparing distal radial access (DRA) with conventional radial access (RA) is available. OBJECTIVES: The aim of this study was to provide a quantitative appraisal of the effects of DRA) vs conventional RA for coronary angiography with or without intervention. METHODS: The PubMed, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov databases were searched for RCT comparing DRA vs conventional RA for coronary angiography and/or intervention. Data were pooled by meta-analysis using a random-effects model. The primary endpoint was radial artery occlusion (RAO) at the longest available follow-up. RESULTS: Fourteen studies enrolling 6,208 participants were included. Compared with conventional RA, DRA was associated with a significant lower risk of RAO, either detected at latest follow-up (risk ratio [RR]: 0.36; 95% CI: 0.23-0.56; P < 0.001; number needed to treat [NNT] = 30) or in-hospital (RR: 0.32; 95% CI: 0.19-0.53; P < 0.001; NNT = 28), as well as EASY (Early Discharge After Transradial Stenting of Coronary Arteries) ≥II hematoma (RR: 0.51; 95% CI: 0.27-0.96; P = 0.04; NNT = 107). By contrast, DRA was associated with a higher risk of access site crossover (RR: 3.08; 95% CI: 1.88-5.06; P < 0.001; NNT = 12), a longer time for radial puncture (standardized mean difference [SMD]: 3.56; 95% CI: 0.96-6.16; P < 0.001), a longer time for sheath insertion (SMD: 0.37; 95% CI: 0.16-0.58; P < 0.001), and a higher number of puncture attempts (SMD: 0.59, 95% CI: 0.48-0.69; P < 0.001). CONCLUSIONS: Compared with conventional RA, DRA is associated with lower risks of RAO and EASY ≥II hematoma but requires longer time for radial artery cannulation and sheath insertion, more puncture attempts, and a higher access site crossover.

Effects on Mortality and Major Bleeding of Radial Versus Femoral Artery Access for Coronary Angiography or Percutaneous Coronary Intervention: Meta-Analysis of Individual Patient Data From 7 Multicenter Randomized Clinical Trials.

BACKGROUND: In some randomized clinical trials, transradial access (TRA) compared with transfemoral access (TFA) was associated with lower mortality in patients with coronary artery disease undergoing invasive management. We analyzed the effects of TRA versus TFA across multicenter randomized clinical trials and whether these associations are modified by patient or procedural characteristics. METHODS: We performed an individual patient data meta-analysis of multicenter randomized clinical trials comparing TRA with TFA among patients undergoing coronary angiography with or without percutaneous coronary intervention. The primary outcome was all-cause mortality and the co-primary outcome was major bleeding at 30 days. The primary analysis was conducted by 1-stage mixed-effects models on the basis of the intention-to-treat cohort. The effect of access site on mortality and major bleeding was assessed further by multivariable analysis. The relationship among access site, bleeding, and mortality was investigated by natural effect model mediation analysis with multivariable adjustment. RESULTS: A total of 21 600 patients (10 775 TRA, 10 825 TFA) from 7 randomized clinical trials were included. The median age was 63.9 years, 31.9% were women, 95% presented with acute coronary syndrome, and 75.2% underwent percutaneous coronary intervention. All-cause mortality (1.6% versus 2.1%; hazard ratio, 0.77 [95% CI, 0.63-0.95]; P=0.012) and major bleeding (1.5% versus 2.7%; odds ratio, 0.55 [95% CI, 0.45-0.67]; P<0.001) were lower with TRA. Subgroup analyses for mortality showed consistent results, except for baseline hemoglobin level (Pinteraction=0.003), indicating that the benefit of TRA was substantial in patients with moderate or severe anemia, whereas it was not significant in patients with milder or no baseline anemia. After adjustment, TRA remained associated with 24% and 51% relative risk reduction of all-cause mortality and major bleeding, respectively. A mediation analysis showed that the benefit of TRA on mortality was only partially driven by major bleeding prevention and ancillary mechanisms are required to fully explain the causal association. CONCLUSIONS: TRA is associated with lower all-cause mortality and major bleeding at 30 days compared with TFA. The effect on mortality was driven by patients with anemia. The reduction in major bleeding only partially explains the mortality benefit. REGISTRATION: URL: https://www.crd.york.ac.uk/prospero; Unique identifier: CRD42018109664.

BMFPs, a versatile therapeutic tool for redirecting a preexisting Epstein-Barr virus antibody response toward defined target cells.

Industrial production of therapeutic monoclonal antibodies is mostly performed in eukaryotic-based systems, allowing posttranslational modifications mandatory for their functional activity. The resulting elevated product cost limits therapy access to some patients. To address this limitation, we conceptualized a novel immunotherapeutic approach to redirect a preexisting polyclonal antibody response against Epstein-Barr virus (EBV) toward defined target cells. We engineered and expressed in bacteria bimodular fusion proteins (BMFPs) comprising an Fc-deficient binding moiety targeting an antigen expressed at the surface of a target cell, fused to the EBV-P18 antigen, which recruits circulating endogenous anti-P18 IgG in EBV+ individuals. Opsonization of BMFP-coated targets efficiently triggered antibody-mediated clearing effector mechanisms. When assessed in a P18-primed mouse tumor model, therapy performed with an anti-huCD20 BMFP significantly led to increased survival and total cancer remission in some animals. These results indicate that BMFPs could represent potent and useful therapeutic molecules to treat a number of diseases.

Bumblebees display characteristics of active vision during robust obstacle avoidance flight.

Insects are remarkable flyers and capable of navigating through highly cluttered environments. We tracked the head and thorax of bumblebees freely flying in a tunnel containing vertically oriented obstacles to uncover the sensorimotor strategies used for obstacle detection and collision avoidance. Bumblebees presented all the characteristics of active vision during flight by stabilizing their head relative to the external environment and maintained close alignment between their gaze and flightpath. Head stabilization increased motion contrast of nearby features against the background to enable obstacle detection. As bees approached obstacles, they appeared to modulate avoidance responses based on the relative retinal expansion velocity (RREV) of obstacles and their maximum evasion acceleration was linearly related to RREVmax. Finally, bees prevented collisions through rapid roll manoeuvres implemented by their thorax. Overall, the combination of visuo-motor strategies of bumblebees highlights elegant solutions developed by insects for visually guided flight through cluttered environments.

Distal Radial Secondary Access for Transcatheter Aortic Valve Implantation: The Minimalistic Approach.

BACKGROUND: Although not yet recommended by the guidelines, distal radial access, a new site for cardiovascular interventions, has been rapidly acknowledged and adopted by many centers due to its high rate of success, safety and fewer complications. We present our experience using secondary distal radial access during transcatheter aortic valve implantation (TAVI), proposing a new, even more minimal approach. METHODS: As of November 2020, a systematic distal radial approach as secondary access site for TAVI was adopted in our center. Primary endpoints were technical success and major adverse events (MAEs). Secondary endpoints: the access site complication rate, hemodynamic and clinical results of the intervention, procedural related factors, crossover rate to the femoral access site, and hospitalization duration (in days). RESULTS: From November 2020, 41 patients underwent TAVI using this strategy. Patients had a mean age of 76 ± 11.2 years, 41% were male. Six (14.63%) patients received a balloon-expandable valve and 35 (85.37%) received a self-expandable valve. TAVI was successful in all cases. No complications occurred due to transradial access. Puncture success, defined as completed sheath placement was maximum (N = 41/41,100%) and emergent transfemoral secondary access was not required in any case. Primary transfemoral vascular access site complications occurred in 7 cases (17%) of which 4 (13.63%) were resolved through distal radial access: one occlusion, two flow-limiting stenoses and four perforations of the common femoral artery. There were no additional major vascular complications at 30 days. Overall MACE rate was 2.4%. CONCLUSION: The use of the distal radial approach for secondary access in TAVI is safe, feasible and has several advantages over old access sites.