Development and validation of the Ex-Care BR model: a multicentre initiative for identifying Brazilian surgical patients at risk of 30-day in-hospital mortality.

BACKGROUND: Surgical risk stratification is crucial for enhancing perioperative assistance and allocating resources efficiently. However, existing models may not capture the complexity of surgical care in Brazil. Using data from various healthcare settings nationwide, we developed a new risk model for 30-day in-hospital mortality (the Ex-Care BR model). METHODS: A retrospective cohort study was conducted in 10 hospitals from different geographic regions in Brazil. Data were analysed using multilevel logistic regression models. Model performance was assessed using the area under the receiver operating characteristic curve (AUROC), Brier score, and calibration plots. Derivation and validation cohorts were randomly assigned. RESULTS: A total of 107,372 patients were included, and 30-day in-hospital mortality was 2.1% (n=2261). The final risk model comprised four predictors related to the patient and surgery (age, ASA physical status classification, surgical urgency, and surgical size), and the random effect related to hospitals. The model showed excellent discrimination (AUROC=0.93, 95% confidence interval [CI], 0.93-0.94), calibration, and overall performance (Brier score=0.017) in the derivation cohort (n=75,094). Similar results were observed in the validation cohort (n=32,278) (AUROC=0.93, 95% CI, 0.92-0.93). CONCLUSIONS: The Ex-Care BR is the first model to consider regional and organisational peculiarities of the Brazilian surgical scene, in addition to patient and surgical factors. It is particularly useful for identifying high-risk surgical patients in situations demanding efficient allocation of limited resources. However, a thorough exploration of mortality variations among hospitals is essential for a comprehensive understanding of risk. CLINICAL TRIAL REGISTRATION: NCT05796024.

Endovascular treatment of mycotic aneurysms: An update meta-analysis.

INTRODUCTION: Intracranial mycotic or infectious aneurysms result from the infection of arterial walls, most caused by bacterial or fungal organisms. These infections can weaken the arterial wall, leading to the formation of an aneurysm, a localized dilation, or a bulge. The management can be conservative mainly based on antibiotics or invasive methods such as clipping or endovascular treatment. PURPOSE: We performed a systematic review and meta-analysis of the current literature on endovascular treatment of mycotic aneurysms, analyzing the safety and efficacy associated with this procedure. METHODS: We systematically searched on PUBMED, Cochrane Library, Embase, and Web of Science databases. Our search strategy was carefully crafted to conduct a thorough investigation of the topic, utilizing a comprehensive combination of relevant keywords. This meta-analysis included all studies that reported endovascular treatment of mycotic aneurysms. To minimize the risk of bias, studies with fewer than four patients, studies where the main outcome was not found, and studies with no clear differentiation between microsurgical and endovascular treatment were excluded. RESULTS: In a comprehensive analysis of 134 patients, it was observed that all except one patient received antibiotics as part of their treatment. Among the patients, 56% (a total of 51 out of 90 patients) underwent cardiac surgery. Additionally, three patients required a craniotomy following endovascular treatment. 12 patients experienced morbidity related to the procedures performed, indicating complications arising from the interventions. Furthermore, four aneurysms experienced rebleeding while treatment. A pooled analysis of the endovascular treatment of the mycotic aneurysm revealed a good level of technical success, achieving a 100% success rate in 12 out of 14 studies (97-100%; CI 95%; I2 = 0%), as illustrated in Fig. 2. Similarly, the aneurysm occlusion rate demonstrated a notable efficacy, with a success rate of 97% observed in 12 out of 14 studies (97-100%; CI 95%; I2 = 0%), as depicted in Fig. 3. CONCLUSION: The results strongly support the efficacy of endovascular treatment in achieving technical success, complete aneurysm occlusion, and favorable neurological outcomes. Additionally, the notably low incidence of complications and procedure-related mortality reaffirms the safety and benefits associated with this intervention.

Nematic superconducting state in iron pnictide superconductors.

Nematic order often breaks the tetragonal symmetry of iron-based superconductors. It arises from regular structural transition or electronic instability in the normal phase. Here, we report the observation of a nematic superconducting state, by measuring the angular dependence of the in-plane and out-of-plane magnetoresistivity of Ba0.5K0.5Fe2As2 single crystals. We find large twofold oscillations in the vicinity of the superconducting transition, when the direction of applied magnetic field is rotated within the basal plane. To avoid the influences from sample geometry or current flow direction, the sample was designed as Corbino-shape for in-plane and mesa-shape for out-of-plane measurements. Theoretical analysis shows that the nematic superconductivity arises from the weak mixture of the quasi-degenerate s-wave and d-wave components of the superconducting condensate, most probably induced by a weak anisotropy of stresses inherent to single crystals.

Local destruction of superconductivity by non-magnetic impurities in mesoscopic iron-based superconductors.

The determination of the pairing symmetry is one of the most crucial issues for the iron-based superconductors, for which various scenarios are discussed controversially. Non-magnetic impurity substitution is one of the most promising approaches to address the issue, because the pair-breaking mechanism from the non-magnetic impurities should be different for various models. Previous substitution experiments demonstrated that the non-magnetic zinc can suppress the superconductivity of various iron-based superconductors. Here we demonstrate the local destruction of superconductivity by non-magnetic zinc impurities in Ba0.5K0.5Fe2As2 by exploring phase-slip phenomena in a mesoscopic structure with 119 × 102 nm(2) cross-section. The impurities suppress superconductivity in a three-dimensional 'Swiss cheese'-like pattern with in-plane and out-of-plane characteristic lengths slightly below ∼1.34 nm. This causes the superconducting order parameter to vary along abundant narrow channels with effective cross-section of a few square nanometres. The local destruction of superconductivity can be related to Cooper pair breaking by non-magnetic impurities.

Method for the solution of the nucleation problem in arbitrary mesoscopic superconductors: theory and application.

We present a method for finding the condensate distribution at the nucleation of superconductivity for arbitrary polygons. The method is based on conformal mapping of the analytical solution of the linearized Ginzburg-Landau problem for the disk and uses the superconducting gauge for the magnetic potential proposed earlier. As a demonstration of the method's accuracy, we calculate the distribution of the order parameter in regular polygons and compare the obtained solutions with available numerical results. As an example of an irregular polygon, we consider a deformed hexagon and prove that its calculation with the proposed method requires the same level of computational efforts as the regular ones. Finally, we extend the method over samples with arbitrary smooth boundaries. With this, we have made simulations for an experimental sample. They have shown perfect agreement with experimental data.