TCT-804 Outcomes of Trans-Carotid TAVR in a high-Volume Center

Background Although the preferred route for transcatheter aortic valve replacement is through the femoral artery, alternatives remain necessary for patients with obstructive iliofemoral disease. Our valve team has developed a large experience using the carotid artery as a primary alternative vascular access approach for transcatheter aortic valve replacement (TAVR). We aim to compare short-term outcomes by access route in a single-center, high-volume, transcarotid (TC) TAVR program. Methods All patients undergoing TAVR between September 2012 and September 2018 were included in the study. Baseline demographics and outcomes were obtained from data our institution submitted in compliance with TVT (Transcatheter Valve Therapy) reporting and are supplemented by individual chart review. Results Overall, 1,153 commercial TAVR procedures were completed during the study period. Of these, 976 (85%) were transfemoral (TF), 105 (9%) were TC, and 72 (6%) were other (53 transapical, 14 transaxillary, 5 transaortic). TF patients had lower Society of Thoracic Surgeons (STS) scores (6.0% vs. 7.1% vs. 8.3%), peripheral vascular disease (24% vs. 88% vs. 72%), and cerebral vascular disease (11% vs. 17% vs. 32%) compared with TC and other patients, respectively (p \u3c 0.001). Combined in-hospital and 30-day mortality was 2.6% for the TF cohort versus 3.8% for TC (p = 0.36) and 13.9% for other (p \u3c 0.001). The stroke rate at 30 days was 3.7% for TF versus 3.8% for TC and 4.2% for other access routes (p = 0.98) (Table). Conclusion TAVR can be safely performed from the TC access route at a high-volume center with similar in-hospital and 30-day mortality and stroke rates compared with TF patients. Mortality was significantly increased, however, in patients treated with other alternative access routes

Actinide covalency measured by pulsed electron paramagnetic resonance spectroscopy

Our knowledge of actinide chemical bonds lags far behind our understanding of the bonding regimes of any other series of elements. This is a major issue given the technological as well as fundamental importance of f-block elements. Some key chemical differences between actinides and lanthanides—and between different actinides—can be ascribed to minor differences in covalency, that is, the degree to which electrons are shared between the f-block element and coordinated ligands. Yet there are almost no direct measures of such covalency for actinides. Here we report the first pulsed electron paramagnetic resonance spectra of actinide compounds. We apply the hyperfine sublevel correlation technique to quantify the electron-spin density at ligand nuclei (via the weak hyperfine interactions) in molecular thorium(III) and uranium(III) species and therefore the extent of covalency. Such information will be important in developing our understanding of the chemical bonding, and therefore the reactivity, of actinides

Organometallic neptunium(III) complexes

Studies of transuranic organometallic complexes provide a particularly valuable insight into covalent contributions to the metal–ligand bonding, in which the subtle differences between the transuranium actinide ions and their lighter lanthanide counterparts are of fundamental importance for the effective remediation of nuclear waste. Unlike the organometallic chemistry of uranium, which has focused strongly on UIII and has seen some spectacular advances, that of the transuranics is significantly technically more challenging and has remained dormant. In the case of neptunium, it is limited mainly to NpIV. Here we report the synthesis of three new NpIII organometallic compounds and the characterization of their molecular and electronic structures. These studies suggest that NpIII complexes could act as single-molecule magnets, and that the lower oxidation state of NpII is chemically accessible. In comparison with lanthanide analogues, significant d- and f-electron contributions to key NpIII orbitals are observed, which shows that fundamental neptunium organometallic chemistry can provide new insights into the behaviour of f-elements