Utility of Dual-Energy Computed Tomography in lesion characterization and treatment planning for peripheral Chronic Total Occlusions: A comprehensive analysis of crossing difficulty.

PURPOSE: To investigate whether Dual-Energy Computed Tomography (DECT) could be useful in the lesion characterization and endovascular treatment planning of symptomatic patients with peripheral arterial disease (PAD) due to Chronic Total Occlusions (CTO). MATERIALS AND METHODS: Between 2018 and 2022, 60 symptomatic patients (52 male, age 71 years) with peripheral arterial CTO underwent DECT angiography before percutaneous endovascular treatment. Patients were classified, according to guidewire crossing difficulty into four categories, which were subsequently correlated with DECT values, including Dual Energy Index (DEI) and Effective Z (Zeff). DECT values were also corelated with crossing time. The crossing difficulty was further correlated with the Trans-Atlantic Inter-Society Consensus Document (TASC II) classification. RESULTS: Technical success, defined as perceived antegrade true lumen or subintimal crossing, was achieved in 76.7 %. Among the cases, 20 were deemed easy, 14 moderate, 12 hard and 14 were failed attempts. Statistical analysis revealed a significant correlation between DEI, Zeff values, and the crossing difficulty categories (p < 0.001). Additionally, there was also a correlation between crossing time and DECT values. However, no significant correlation was recorded between difficulty categories and TASC II classification. CONCLUSION: Pre-procedural DECT angiography provides valuable information for patient selection and planning of the revascularization strategy. Moreover, it is helpful in the selection of the appropriate PTA materials, based on the lesion characteristics. Further research should be invested in this important field, to determine the optimal treatment approach in patients suffering from PAD due to CTOs.

Multiple environmental stressors affect predation pressure in a tropical freshwater system.

Environmental change can alter predator-prey dynamics. However, studying predators in the context of co-occurring environmental stressors remains rare, especially under field conditions. Using in situ filming, we examined how multiple stressors, including temperature and turbidity, impact the distribution and behaviour of wild fish predators of Trinidadian guppies (Poecilia reticulata). The measured environmental variables accounted for 17.6% of variance in predator species composition. While predator species differed in their associations with environmental variables, the overall prevalence of predators was greatest in slow flowing, deeper, warmer and less turbid habitats. Moreover, these warmer and less turbid habitats were associated with earlier visits to the prey stimulus by predators, and more frequent predator visits and attacks. Our findings highlight the need to consider ecological complexity, such as co-occurring stressors, to better understand how environmental change affects predator-prey interactions.

Concomitant vascular and orthopedic trauma: 10 points to consider.

Although vascular injuries complicate only 1-2% of patients with orthopedic trauma, they may be encountered in a much higher rate of around 10 % in injuries around the knee and elbow joints following both fractures and dislocations. In case of vascular involvement, specific diagnostic and therapeutic challenges arise and there is a higher risk for significant morbidity (i.e. limb loss) or mortality. In the absence of randomized data, diagnostic and therapeutic algorithms are not always straightforward and clinical practice may be based on experience and local protocols rather than firm evidence. With this article we intend to review available literature regarding concomitant skeletal and vascular trauma in order to provide concise information and clear guidelines of when to operate with least investigations and when to go for a full spectrum of investigations in the absence of hard clinical signs. Additionally, other aspects concerning the manipulation of these patients are discussed, such as the indications of primary amputation, the potential role of endovascular techniques and the value of the Resuscitative Endovascular Balloon Occlusion of the Aorta. In summary, this scoping review summarizes current practices in the diagnostic and therapeutic management of patients with concomitant orthopedic and vascular injuries, discusses different treatment strategies and gives a practical perspective for implementation on every day practice.

Technical challenges during emergent endovascular aneurysm repair with the ALTO system.

INTRODUCTION: Ruptured abdominal aortic aneurysms (AAAs) pose an immediate threat for patient's life and endovascular repair (EVAR) is currently the preferred treatment modality in the presence of suitable anatomy. This is determined based on the requirements of each endograft as described in the instructions for use (IFU). The new ALTO system (Endologix, Irvin, CA, U.S.A.), can accommodate a great range of anatomies such as short necks and/or narrow access, but its unique design requires specific technical modifications during treatment of ruptured AAAs. AREAS COVERED: The standard double balloon technique has long been described and it is used to provide circulatory support during EVAR for ruptured AAA. While this technique is straightforward with the use of endografts with a traditional design, this would not be the case if one uses the ALTO system. In that case specific maneuvers would be required to treat AAA patients in an acute setting. EXPERT OPINION: The ALTO system although being able to treat AAAs with adverse anatomy, it may not be appropriate during treatment of ruptured AAA patients with profound hemodynamic instability. A careful evaluation of the individual's patient anatomy and hemodynamic condition is mandatory in order to decide the best endograft for each case.

A hemodynamic study of blood flow models on various stent graft configurations during aorto-iliac reconstruction.

PURPOSE: To compare the hemodynamic performance of three (Bottom Up non-ballet, Top-Down non-ballet, Top Down ballet) idealized stent graft configurations used during endovascular repair of abdominal aortic aneurysms, under the influence of various rheological models. METHODS: Ten rheological models are assumed and a commercial finite volume solver is employed for the simulation of blood flow under realistic boundary conditions. An appropriate mesh convergence study is performed and five hemodynamic variables are computed: the time average wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), endothelial cell activation potential (ECAP) and displacement force (DF) for all three configurations. RESULTS: The choice of blood flow model may affect results, but does not constitute a significant determinant on the overall performance of the assumed stent grafts. On the contrary, stent graft geometry has a major effect. Specifically, the Bottom Up non-ballet type is characterized by the least favorable performance presenting the lowest TAWSS and the highest OSI, RRT and ECAP values. On the other hand, the Top Down ballet type presents hemodynamic advantages yielding the highest TAWSS and lowest OSI, RRT and ECAP average values. Furthermore, the ballet type is characterized by the lowest DF, although differences observed are small and their clinical relevance uncertain. CONCLUSIONS: The effect of the assumed rheological model on the overall performance of the grafts is not significant. It is thus relatively safe to claim that it is the type of stent graft that determines its overall performance rather than the adopted blood flow model.

The impact of late pregnancy dating on the detection of fetal growth restriction at term.

INTRODUCTION: The inaccuracy of late pregnancy dating is often discussed, and the impact on diagnosis of fetal growth restriction is a concern. However, the magnitude and direction of this effect has not previously been demonstrated. In this study, we aimed to investigate the effect of late pregnancy dating by head circumference on the detection of late onset growth restriction, compared to first trimester crown-rump length dating. MATERIAL AND METHODS: This was a cohort study of 14 013 pregnancies receiving obstetric care at a tertiary center over a three-year period. Universal scans were performed at 12 weeks, including crown-rump length; at 20 weeks including fetal biometry; and at 36 weeks, where biometry, umbilical artery doppler and cerebroplacental ratio were used to determine the incidence of fetal growth restriction according to the Delphi consensus. For the entire cohort, the gestational age was first calculated using T1 dating; and was then recalculated using head circumference at 20 weeks (T2 dating); and at 36 weeks (T3 dating). The incidence of fetal growth restriction following T2 and T3 dating was compared to T1 dating using four-by-four sensitivity tables. RESULTS: When the cohort was redated from T1 to T2, the median gestation at delivery changed from 40 + 0 to 40 + 2 weeks (p < 0.001). When the cohort was redated from T1 to T3, the median gestation at delivery changed from 40 + 0 to 40 + 3 weeks (p < 0.001). T2 dating resulted in fetal growth restriction sensitivity of 80.2% with positive predictive value of 78.8% compared to T1 dating. T3 dating resulted in sensitivity of 8.6% and positive predictive value of 27.7%, respectively. The sensitivity of abnormal CPR remained high despite T2 and T3 redating; 98.0% and 89.4%, respectively. CONCLUSIONS: Although dating at 11-14 weeks is recommended, late pregnancy dating is sometimes inevitable, and this can prolong the estimated due date by an average of two to three days. One in five pregnancies which would be classified as growth restricted if the pregnancy was dated in the first trimester, will be reclassified as nongrowth restricted following dating at 20 weeks, whereas nine out of 10 pregnancies will be reclassified as non-growth restricted with 36-week dating.

Shoaling behaviour in response to turbidity in three-spined sticklebacks.

Many fresh and coastal waters are becoming increasingly turbid because of human activities, which may disrupt the visually mediated behaviours of aquatic organisms. Shoaling fish typically depend on vision to maintain collective behaviour, which has a range of benefits including protection from predators, enhanced foraging efficiency and access to mates. Previous studies of the effects of turbidity on shoaling behaviour have focussed on changes to nearest neighbour distance and average group-level behaviours. Here, we investigated whether and how experimental shoals of three-spined sticklebacks (Gasterosteus aculeatus) in clear (<10 Nephelometric Turbidity Units [NTU]) and turbid (~35 NTU) conditions differed in five local-level behaviours of individuals (nearest and furthest neighbour distance, heading difference with nearest neighbour, bearing angle to nearest neighbour and swimming speed). These variables are important for the emergent group-level properties of shoaling behaviour. We found an indirect effect of turbidity on nearest neighbour distances driven by a reduction in swimming speed, and a direct effect of turbidity which increased variability in furthest neighbour distances. In contrast, the alignment and relative position of individuals was not significantly altered in turbid compared to clear conditions. Overall, our results suggest that the shoals were usually robust to adverse effects of turbidity on collective behaviour, but group cohesion was occasionally lost during periods of instability.

Retroperitoneal Soft Tissue Sarcoma: Emerging Therapeutic Strategies.

Retroperitoneal soft tissue sarcoma (RPS) is a rare and heterogenous disease for which surgery is the cornerstone of treatment. However, the local recurrence rate is much higher than in soft tissue sarcoma of the extremities since wide resection is usually unfeasible in RPS due to its large size, indistinct tumour borders, anatomical constraints and the thinness of the overlying peritoneum. Local recurrence is the leading cause of death for low-grade RPS, whereas high-grade tumours are prone to distant metastases. In recent decades, the role of emerging therapeutic strategies, such as more extended surgery and (neo)adjuvant treatments to improve oncological outcome in primary localised RPS, has been extensively investigated. In this review, the recent data on the evolving multidisciplinary management of primary localised RPS are comprehensively discussed. The heterogeneity of RPS, with their different histological subtypes and biological behaviour, renders a standard therapeutic 'one-size-fits-all' approach inappropriate, and treatment should be modified according to histological type and malignancy grade. There is sufficient evidence that frontline extended surgery with compartmental resection including all ipsilateral retroperitoneal fat and liberal en bloc resection of adjacent organs and structures, even if they are not macroscopically involved, increases local tumour control in low-grade sarcoma and liposarcoma, but not in leiomyosarcoma for which complete macroscopic resection seems sufficient. Additionally, preoperative radiotherapy is not indicated for all RPSs, but seems to be beneficial in well-differentiated liposarcoma and grade I/II dedifferentiated liposarcoma, and probably in solitary fibrous tumour. Whether neoadjuvant chemotherapy is of benefit in high-grade RPS remains unclear from retrospective data and is subject of the ongoing randomised STRASS 2 trial, from which the results are eagerly awaited. Personalised, histology-tailored multimodality treatment is promising and will likely further evolve as our understanding of the molecular and genetic characteristics within RPS improves.

Systematic Review and Meta-Analysis of the Effect of Anticoagulation on Outcomes After Endovascular Aneurysm Repair.

PURPOSE: Our objective was to investigate whether patients who receive anticoagulation therapy have different outcomes after endovascular aneurysm repair (EVAR) from those who do not. MATERIALS AND METHODS: We conducted a systematic review of studies that compared outcomes of EVAR in patients who were on therapeutic anticoagulation vs those who were not. We developed and reported the review in accordance with the PRISMA guidelines with a registered protocol (CRD42022375894). The Ovid interface was used to search Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica Database (EMBASE), and Cochrane Central Register of Controlled Trials (CENTRAL) up to November 2022. The quality of studies was assessed with the Newcastle-Ottawa Scale (NOS) (maximum score=9), and the evidence was appraised with the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework. The hazard ratio (HR) and 95% confidence interval (CI) was the effect estimate in time-to-event meta-analyses, calculated using the inverse-variance statistical method and random-effects models. RESULTS: Sixteen studies qualified for inclusion reporting a total of 35 739 individuals. Anticoagulated patients had a statistically significantly higher hazard of death (HR=1.93, 95% CI=1.03-3.63), endoleak (HR=2.13, 95% CI=1.55-2.93), reintervention (HR=1.79, 95% CI=1.27-2.52), and aneurysm sac expansion (HR=2.72, 95% CI=1.57-4.72) than patients not receiving anticoagulation therapy. The median score on the NOS was 7 (range=4-9). The certainty of evidence was very low for mortality and reintervention and low for endoleak and sac expansion. CONCLUSIONS: Anticoagulation is a poor prognostic factor after standard EVAR and should be considered in decision-making, consent processes, and surveillance strategies. CLINICAL IMPACT: The number of individuals who take anticoagulation treatment has been rapidly increasing over the recent years. We aimed to investigate the effect of such treatment on outcomes after endovascular aneurysm repair (EVAR). Anticoagulated patients were found to have increased mortality, endoleak, and reintervention rates after EVAR compared to their non-anticoagulated counterparts. Anticoagulation therapy has a prognostic role in EVAR and should be considered in decision making and EVAR surveillance. Anticoagulated patients need to be informed of the higher failure rates of EVAR, and intensified surveillance strategies may need to be implemented in this patient cohort.

Comparison of the Haemodynamic Performance of Various Treatment Options for Aorto-Iliac Occlusive Disease.

Introduction: Several surgical and endovascular techniques are used during the treatment of aorto-iliac occlusive disease. Aortobifemoral bypass (AoBFB) is the standard of care, but other options such as axillobifemoral (AxBFB) bypass, aorto-iliac kissing stents (KS), and covered endovascular reconstruction of aortic bifurcation (CERAB) are also available. This study aimed to perform a computational comparison of these four modalities to investigate their haemodynamic performance. Report: Eight patient specific anatomies were analysed, with each of the abovementioned techniques used to treat two anatomies. The CT angiograms were segmented from the renal (or axillary) to common femoral arteries and the 3D geometries were exported. A commercial finite volume solver was implemented for numerical simulations. Outcomes that were assessed were pressure drop (ΔP) between the inlet and the outlet for every configuration and haemodynamic indices of Time Average Wall Shear Stress (TAWSS), Oscillatory Shear Index (OSI), and Relative Residence Time (RRT) as markers of a thrombogenic environment. The results indicate that maximum ΔP was observed at peak systole for all models, with values ranging between 12 mmHg and 21 mmHg for the AoBFB, 64 mmHg and 96 mmHg for the AxBFB, 31 mmHg and 46 mmHg for the KS, and 43 mmHg and 46 mmHg for the CERAB configuration. TAWSS, OSI, and RRT varied among different configurations, mostly presenting values well above thrombogenic thresholds. Regarding RRT, the percentage of total surface area presenting such values is 2.5%, 3.2%, 2%, and 4.3% for the AoBFB, AxBFB, KS, and CERAB configurations, respectively. Discussion: Computational modelling indicates a favourable haemodynamic performance of AoBFB compared with the other configurations. This leads to a smaller pressure drop and sconsequently a higher pressure in the outlet of the conduit, which is the perfusion pressure of the limb. Notably, lower patency rates of the latter modalities cannot be explained based on haemodynamic indices.

Selection of Bifurcated Grafts' Dimensions during Aorto-Iliac Vascular Reconstruction Based on Their Hemodynamic Performance.

During the vascular surgical reconstruction of aorto-iliac occlusive/aneurysmal disease, bifurcated grafts are used where vascular surgeons intra-operatively select the size and the relative lengths of the parent and daughter portions of the graft. Currently, clinical practice regarding the selection of the most favorable geometric configuration of the graft is an understudied research subject: decisions are solely based on the clinical experience of the operating surgeon. This manuscript aims to evaluate the hemodynamic performance of various diameters, D, of bifurcated aortic grafts and relate those with proximal/distal part length ratios (the angle φ between the limbs is used as a surrogate marker of the main body-to-limb length ratio) in order to provide insights regarding the effects of different geometries on the hemodynamic environment. To this end, a computationally intensive set of simulations is conducted, and the resulting data are analyzed with modern statistical regression tools. A negative curvilinear relationship of TAWSS with both φ and D is recorded. It is shown that the angle between limbs is a more important predictor for the variability of TAWSS, while the graft's diameter is an important determinant for the variability of OSI. Large percentages of the total graft area with TAWSS < 0.4 Pa, which correspond to thrombogenic stimulating environments, are only observed for large values of φ and D > 20 mm. This variable ranges from 10% (for the smallest values of φ and D) to 55% (for the largest φ and D values). Our findings suggest that grafts with the smallest possible angle between the limbs (i.e., smallest parent-to-daughter length ratio) present the most favorable hemodynamic performance, yielding the smallest percentage of total graft area under thrombogenic simulating environments. Similarly, grafts with the smallest acceptable diameter should be preferred for the same reason. Especially, grafts with diameters greater than 20 mm should be avoided, given the abrupt increase in estimated thrombogenic areas.

Virtual prey with Lévy motion are preferentially attacked by predatory fish.

Of widespread interest in animal behavior and ecology is how animals search their environment for resources, and whether these search strategies are optimal. However, movement also affects predation risk through effects on encounter rates, the conspicuousness of prey, and the success of attacks. Here, we use predatory fish attacking a simulation of virtual prey to test whether predation risk is associated with movement behavior. Despite often being demonstrated to be a more efficient strategy for finding resources such as food, we find that prey displaying Lévy motion are twice as likely to be targeted by predators than prey utilizing Brownian motion. This can be explained by the predators, at the moment of the attack, preferentially targeting prey that were moving with straighter trajectories rather than prey that were turning more. Our results emphasize that costs of predation risk need to be considered alongside the foraging benefits when comparing different movement strategies.

Temperature and turbidity interact synergistically to alter anti-predator behaviour in the Trinidadian guppy.

Due to climate change, freshwater habitats are facing increasing temperatures and more extreme weather that disrupts water flow. Together with eutrophication and sedimentation from farming, quarrying and urbanization, freshwaters are becoming more turbid as well as warmer. Predators and prey need to be able to respond to one another adaptively, yet how changes in temperature and turbidity interact to affect predator-prey behaviour remains unexplored. Using a fully factorial design, we tested the combined effects of increased temperature and turbidity on the behaviour of guppy shoals (Poecilia reticulata) in the presence of one of their natural cichlid predators, the blue acara (Andinoacara pulcher). Our results demonstrate that the prey and predator were in closest proximity in warmer, turbid water, with an interaction between these stressors showing a greater than additive effect. There was also an interaction between the stressors in the inter-individual distances between the prey, where shoal cohesion increased with temperature in clear water, but decreased when temperature increased in turbid water. The closer proximity to predators and reduction in shoaling in turbid, warmer water may increase the risk of predation for the guppy, suggesting that the combined effects of elevated temperature and turbidity may favour predators rather than prey.

Systematic Review With Meta-Analysis of Endovascular Versus Open Repair of Abdominal Aortic Aneurysm Repair in the Young.

PURPOSE: The purpose of this study was to investigate which treatment method for abdominal aortic aneurysm (AAA), endovascular or open repair, has better outcomes in young patients. MATERIALS AND METHODS: A systematic review was conducted to identify observational studies or randomized controlled trials (RCTs) that compared endovascular and open repair of intact AAA in young patients. MEDLINE, EMBASE, and CENTRAL were searched up to March 2022 using the Ovid interface. The risk of bias was assessed with the Newcastle-Ottawa scale (NOS), with a maximum score of 9, or version 2 of the Cochrane risk of bias tool. The certainty of evidence was assessed with the GRADE framework. Primary outcomes were perioperative, overall, and aneurysm-related mortality. Secondary outcomes were reintervention, hospital length of stay, and perioperative complications. Effect measures in syntheses were the odds ratio (OR), risk difference (RD), mean difference (MD), or hazard ratio (HR) and were calculated with the Mantel-Haenszel or inverse variance statistical method and random-effects models. RESULTS: Fifteen observational studies and 1 RCT were included, reporting a total of 48 976 young patients. Definitions of young ranged from 60 to 70 years. The median score on the NOS was 8 (range: 4-9), and the RCT was judged to be high risk of bias. The perioperative mortality was lower after EVAR (RD: -0.01, 95% CI: -0.02 to -0.00), but the overall and aneurysm-related mortality was not significantly different between EVAR and open repair (HR: 1.38, 95% CI: 0.81 to 2.33; HR: 4.68, 95% CI: 0.71 to 31.04, respectively), as was the hazard of reintervention (HR: 1.50, 95% CI: 0.88 to 2.56). The hospital length of stay was shorter after EVAR (MD: -4.44 days, 95% CI: -4.79 to -4.09), and the odds of cardiac (OR: 0.22, 95% CI: 0.13 to 0.35), respiratory (OR: 0.17, 95% CI: 0.11 to 0.26), and bleeding complications were lower after EVAR (OR: 0.26, 95% CI: 0.11 to 0.64). The level of evidence was low or very low. CONCLUSION: Patient preferences and perspectives should be considered during shared decision-making process considering the available evidence. EVAR may be considered in young and fit patients with a suitable anatomy. PROTOCOL REGISTRATION: PROSPERO, CRD42022325051. CLINICAL IMPACT: Uncertainty surrounds the optimal treatment strategy for abdominal aortic aneurysm in young patients. Meta-analysis of some 48,976 young patients showed that endovascular aneurysm repair (EVAR) has a lower perioperative mortality and morbidity and a shorter hospital and intensive care unit stay than open surgical repair, but the overall and aneurysm-related mortality in the short to medium term are not significantly different between EVAR and open repair. EVAR can be considered in young patients.

Long-Term Muscular Atrophy and Weakness Following Cessation of Botulinum Toxin Type A Injections in the Flexor Digitorum Muscle of Musicians with Focal Hand Dystonia.

The present study assessed muscular atrophy and weakness of the flexor digitorum superficialis (FDS) and profundus (FDP) muscle as possible long-term side effects of botulinum toxin (BoNT) injections in hand dystonia patients after the termination of their treatment. For the assessment of both parameters, a group of 12 musicians diagnosed with focal hand dystonia was compared with a group of 12 healthy matched musicians. The minimum and maximum times since the last injection across patients were 0.5 to 3.5 years, respectively. The thickness and strength of the FDS and FDP were assessed via ultrasonography and a strength measurement device. Group differences were estimated through the calculation of the symmetry index between the dominant and non-dominant hand. The results revealed that compared to the control group, thickness and flexion strength of the injected FDS and FDP were decreased by 10.6% ± 5.3% (95% CI) and 12.5% ± 6.4% (95% CI), respectively, in the patient group. The amount of weakness and atrophy was predicted significantly by the total amount of BoNT injected throughout the entire treatment period. In contrast, the time after the last injection did not predict the amount of strength and muscle mass recovery after the cessation of the treatment. The current study revealed that even up to 3.5 years after the termination of BoNT injections, long-term side effects such as weakness and atrophy can still be observed. We suggest that the total BoNT dose should remain as small as possible to reduce long-lasting side effects to the minimum. Although side effects differ significantly among patients, a potential full recovery of atrophy and weakness after the cessation of BoNT treatment might be observed after periods longer than 3.5 years.

Does the Routine Skin-Only Closure in Ruptured Abdominal Aortic Aneurysm Repair Safely Diminish Abdominal Compartment Syndrome? A Hypothesis Generating Retrospective Study.

BACKGROUND: Abdominal compartment syndrome (ACS) often complicates ruptured abdominal aortic aneurysm (rAAA) repair. We report results with routine skin-only abdominal wound closure after rAAA surgical repair. METHODS: This was a single-center retrospective study including consecutive patients undergoing rAAA surgical repair for the duration of 7 years. Skin-only closure was routinely performed, and if possible, secondary abdominal closure was performed during the same admission. Demographic information, preoperative hemodynamic condition, and perioperative information (ACS, mortality, rate of abdominal closure, and postoperative outcomes) were collected. RESULTS: During the study period, 93 rAAAs were recorded. Ten patients were too frail to undergo repair or refused treatment. Eighty-three patients underwent immediate surgical repair. The mean age was 72.4 ± 10.5 years, and the vast majority were male (82:1). Preoperative systolic blood pressure <90 mm Hg was recorded in 31 patients. Intraoperative mortality was recorded in nine cases. Overall in-hospital mortality was 34.9% (29/83). Primary fascial closure was performed in five patients, while skin-only closure was performed in 69. ACS was recorded in two cases in whom skin sutures were removed and negative pressure wound treatment was applied. Secondary fascial closure was feasible in 30 patients during the same admission. Among 37 patients not undergoing fascial closure, 18 died and 19 survived and were discharged with a planned ventral hernia repair. Median length of intensive care unit and hospital stay were 5 (1-24) and 13 (8-35) days, respectively. After a mean follow-up of 21 months, telephone contact was possible with 14/19 patients who left the hospital with an abdominal hernia. Three reported hernia-related complications mandating surgical repair, while in 11, this was well tolerated. CONCLUSION: Routine skin-only closure during rAAA surgical repair results in low rates of ACS at the expense of a high rate of patients being discharged with a planned ventral hernia which, however, seems to be well tolerated by the majority of patients.

Increased water temperature and turbidity act independently to alter social behavior in guppies (Poecilia reticulata).

Changes in environmental conditions can shift the costs and benefits of aggregation or interfere with the sensory perception of near neighbors. This affects group cohesion with potential impacts on the benefits of collective behavior such as reduced predation risk. Organisms are rarely exposed to one stressor in isolation, yet there are only a few studies exploring the interactions between multiple stressors and their effects on social behavior. Here, we tested the effects of increased water temperature and turbidity on refuge use and three measures of aggregation in guppies (Poecilia reticulata), increasing temperature and turbidity in isolation or in combination. When stressors were elevated in isolation, the distribution of fish within the arena as measured by the index of dispersion became more aggregated at higher temperatures but less aggregated when turbidity was increased. Another measure of cohesion at the global scale, the mean inter-individual distance, also indicated that fish were less aggregated in turbid water. This is likely due to turbidity acting as a visual constraint, as there was no evidence of a change in risk perception as refuge use was not affected by turbidity. Fish decreased refuge use and were closer to their nearest neighbor at higher temperatures. However, the nearest neighbor distance was not affected by turbidity, suggesting that local-scale interactions can be robust to the moderate increase in turbidity used here (5 NTU) compared with other studies that show a decline in shoal cohesion at higher turbidity (>100 NTU). We did not observe any significant interaction terms between the two stressors, indicating no synergistic or antagonistic effects. Our study suggests that the effects of environmental stressors on social behavior may be unpredictable and dependent on the metric used to measure cohesion, highlighting the need for mechanistic studies to link behavior to the physiology and sensory effects of environmental stressors.