Periprocedural Direct Oral Anticoagulant Management: The RA-ACOD Prospective, Multicenter Real-World Registry.

Introduction There is scarce real-world experience regarding direct oral anticoagulants (DOACs) perioperative management. No study before has linked bridging therapy or DOAC-free time (pre-plus postoperative time without DOAC) with outcome. The aim of this study was to investigate real-world management and outcomes. Methods RA-ACOD is a prospective, observational, multicenter registry of adult patients on DOAC treatment requiring surgery. Primary outcomes were thrombotic and hemorrhagic complications. Follow-up was immediate postoperative (24-48 hours) and 30 days. Statistics were performed using a univariate and multivariate analysis. Data are presented as odds ratios (ORs [95% confidence interval]). Results From 26 Spanish hospitals, 901 patients were analyzed (53.5% major surgeries): 322 on apixaban, 304 on rivaroxaban, 267 on dabigatran, 8 on edoxaban. Fourteen (1.6%) patients suffered a thrombotic event, related to preoperative DOAC withdrawal (OR: 1.57 [1.03-2.4]) and DOAC-free time longer than 6 days (OR: 5.42 [1.18-26]). Minor bleeding events were described in 76 (8.4%) patients, with higher incidence for dabigatran (12.7%) versus other DOACs (6.6%). Major bleeding events occurred in 17 (1.9%) patients. Bridging therapy was used in 315 (35%) patients. It was associated with minor (OR: 2.57 [1.3-5.07]) and major (OR: 4.2 [1.4-12.3]) bleeding events, without decreasing thrombotic events. Conclusion This study offers real-world data on perioperative DOAC management and outcomes in a large prospective sample size to date with a high percentage of major surgery. Short-term preprocedural DOAC interruption depending on the drug, hemorrhagic risk, and renal function, without bridging therapy and a reduced DOAC-free time, seems the safest practice.

On the difficulties of present theoretical models to predict the oxidation state of atomic Au adsorbed on regular sites of CeO2(111).

The electronic structure and oxidation state of atomic Au adsorbed on a perfect CeO(2)(111) surface have been investigated in detail by means of periodic density functional theory-based calculations, using the LDA+U and GGA+U potentials for a broad range of U values, complemented with calculations employing the HSE06 hybrid functional. In addition, the effects of the lattice parameter a(0) and of the starting point for the geometry optimization have also been analyzed. From the present results we suggest that the oxidation state of single Au atoms on CeO(2)(111) predicted by LDA+U, GGA+U, and HSE06 density functional calculations is not conclusive and that the final picture strongly depends on the method chosen and on the construction of the surface model. In some cases we have been able to locate two well-defined states which are close in energy but with very different electronic structure and local geometries, one with Au fully oxidized and one with neutral Au. The energy difference between the two states is typically within the limits of the accuracy of the present exchange-correlation potentials, and therefore, a clear lowest-energy state cannot be identified. These results suggest the possibility of a dynamic distribution of Au(0) and Au(+) atomic species at the regular sites of the CeO(2)(111) surface.

V@Au12-: an improved novel catalyst for CO oxidation?

The catalytic properties toward CO combustion of an encapsulated cluster, V@Au12-, have been explored by means of plane-wave pseudopotential density-functional theory calculations. Single adsorption of both O2 and CO as well as coadsorption have been considered. The adsorption energy for the O2 molecule is about 0.3-0.4 eV which limits its use to low temperatures. However, in contrast to what happens for pure gold clusters, this system shows a remarkable capacity to bind a high number of oxygen molecules. Moreover, its icosahedral cluster is able to bind 12 CO molecules, since all of the gold atoms are available. The bond between the metal cluster and the oxygen molecule mainly arises from a charge transfer from the metal toward the pi(g) antibonding O2 orbitals, while in the case of CO molecule, the classical sigma-donation pi-back-donation mechanism is observed. Finally, no coadsorption effects are found when both molecules are adsorbed, the interaction properties between the cluster and the substrates remain basically unaltered.

Adsorption of Acetone onto MgO: Experimental and Theoretical Evidence for the Presence of a Surface Enolate.

A new band at 1640 cm-1 is revealed by diffuse reflectance FT-IR spectroscopy of acetone adsorbed on a MgO surface (shown schematically). On the grounds of ab initio quantum-mechanical calculations, this band is assigned to an adsorbed enolate species. This evidence proves the catalytic role of the metal oxide surface in the condensation reaction mechanism.