462 research outputs found

    Impact of asymmetric tethering on outcomes after edge-to-edge mitral valve repair for secondary mitral regurgitation

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    BACKGROUND The impact of postero-anterior and medio-lateral mitral valve (MV) tethering patterns on outcomes in patients undergoing transcatheter edge-to-edge repair (M-TEER) for secondary mitral regurgitation (SMR) is unknown. METHODS The ratio of the posterior to anterior MV leaflet angle (PLA/ALA) in MV segment 2 was defined as postero-anterior tethering asymmetry. Medio-lateral tethering asymmetry was assessed as the ratio of the medial (segment 3) to lateral (segment 1) MV tenting area. We used receiver-operating characteristics and a Cox regression model to identify cut-off values of asymmetric anteroposterior and medio-lateral tethering for prediction of 2~year all-cause mortality after TMVR. RESULTS Among 178 SMR patients, postero-anterior tethering was asymmetric in 67 patients (37.9%, PLA/ALA ratio > 1.54). Asymmetric medio-lateral tethering (tenting area ratio > 1.49) was observed in 49 patients (27.5%). M-TEER reduced MR to ≤ 2 + in 92.1% of patients; MR reduction was less effective in the presence of asymmetric postero-anterior tethering (p = 0.02). A multivariable Cox regression model identified both types of asymmetric MV tethering to be associated with increased all-cause 2-year mortality (postero-anterior tethering asymmetry: HR = 2.77, CI 1.43-5.38; medio-lateral tethering asymmetry: HR = 2.90, CI 1.54-5.45; p < 0.01). CONCLUSIONS Asymmetric postero-anterior and medio-lateral MV tethering patterns are associated with increased 2-year mortality in patients undergoing M-TEER for SMR. A detailed echocardiographic analysis of MV anatomy may help to identify patients who profit most from M-TEER

    The Milky Way like galaxy NGC 6384 and its nuclear star cluster at high NIR spatial resolution using LBT/ARGOS commissioning data

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    We analyse high spatial resolution near infra-red (NIR) imaging of NGC6384, a Milky Way like galaxy, using ARGOS commissioning data at the Large Binocular Telescope (LBT). ARGOS provides a stable PSFFWHM ⁣= ⁣0.2" ⁣ ⁣0.3"_{\rm FWHM}\!=\!0.2"\!-\!0.3" AO correction of the ground layer across the LUCI2 NIR camera 4 ⁣×44'\!\times4' field by using six laser guide stars (three per telescope) and a natural guide star for tip-tilt sensing and guiding. Enabled by this high spatial resolution we analyse the structure of the nuclear star cluster (NSC) and the central kiloparsec of NGC6384. We find via 2D modelling that the NSC (reff ⁣ ⁣10r_{\rm eff}\!\simeq\!10pc) is surrounded by a small (reff ⁣ ⁣100r_{\rm eff}\!\simeq\!100pc) and a larger Sersi\'c (reff ⁣ ⁣400r_{\rm eff}\!\simeq\!400pc), all embedded within the NGC\,6384 large-scale boxy/X-shaped bulge and disk. This proof-of-concept study shows that with the high spatial resolution achieved by ground-layer AO we can push such analysis to distances previously only accessible from space. SED-fitting to the NIR and optical HST photometry allowed to leverage the age-metallicity-extinction degeneracies and derive the effective NSC properties of an young to old population mass ratio of 8%8\% with M,old ⁣ ⁣3.5×107M{\cal M}_{\rm\star,old}\!\simeq\!3.5\times10^7M_\odot, Age$_{\rm old,\ young}\!=\!10.9\pm1.3Gyrand226MyrGyr and 226\,Myr \pm62\%,metallicity[M/H], metallicity [M/H]=\!-0.11\pm0.16and and 0.33\pm39\%dex,anddex, and E(B\!-\!V)\!=\!0.63$ and 1.44mag.Comment: 12 pages (+9 appendix), 11 figures, Accepted in MNRA

    Right ventricular function in transcatheter mitral and tricuspid valve edge-to-edge repair

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    Since transcatheter edge-to-edge repair (TEER) has become a valuable therapy in the treatment of both, mitral (MR) and tricuspid regurgitation (TR), the question of optimized patient selection has gained growing importance. After years of attributing rather little attention to the right ventricle (RV) and its function in the setting of valvular heart failure, this neglect has recently changed. The present review sought to summarize anatomy and function of the RV in a clinical context and aimed at presenting the current knowledge on how the RV influences outcomes after TEER for atrioventricular regurgitation. The anatomy of the RV is determined by its unique shape, which necessitates to use three-dimensional imaging methods for detailed and comprehensive characterization. Complex parameters such as RV to pulmonary artery coupling (RVPAc) have been developed to combine information of RV function and afterload which is primary determined by the pulmonary vasculature and LV filling pressure. Beyond that, TR, which is closely related to RV function also plays an important role in the setting of TEER. While mitral valve transcatheter edge-to-edge repair (M-TEER) leads to reduction of concomitant TR in some patients, the prognostic value of TR in the setting of M-TEER remains unclear. Overall, this review summarizes the current state of knowledge of the outstanding role of RV function and associated TR in the setting of TEER and outlines the unsolved questions associated with right-sided heart failure

    Prevalence of donor-transmitted atherosclerosis—Clinical utility of intracoronary ultrasound early after heart transplantation. A single-center study

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    AbstractIntroductionCoronary allograft vasculopathy (CAV) is one of the main factors limiting long-term survival following orthotopic heart transplantation (HTx). Whether or not and, if so, how donor-transmitted atherosclerosis (DCA) affects the post-transplant course of the allograft recipient is still unclear. Conventional coronary angiography is a moderately accurate technique for DCA detection as it will reveal only the more gross morphological lesions. By contrast, intravascular ultrasound (IVUS) has been shown to be a much more sensitive technique for CAV and DCA detection. In our study we sought to determine the prevalence of DCA in our HTx patient population and identify main risk factors of DCA based on donor characteristics.Patients and methodsWe performed a retrospective analysis of data of 119 patients (92 men, 27 women) undergoing transplantation in our center from August 2006 through September 2012, who had survived their first post-transplant month and had coronary angiography and IVUS.ResultsDCA was present in 39 patients, and not documented in 80 patients. The main risk factors for DCA included donor age, cigarette smoking, and hypertension; the other parameters were not shown to be statistically significant. In-hospital mortality was low in both groups (DCA positive and DCA negative), with one patient dying in either group. One-year mortality rates post-HTx were likewise almost identical in both groups (15.4% and 15% in DCA positive and negative, respectively).ConclusionThe prevalence of DCA in our patients was 32.8%, with major risk factors for DCA including donor age, cigarette smoking, and hypertension. As age seems to be the strongest predictor, coronary angiography should be a routine examination in individuals aged over 40 years; the examination should be considered in younger individuals with a cluster of several of risk factors. The 1-year survival in this selected patient population was identical in both groups, the implication being that the diagnosis of DCA had no effect on 1-year survival post-HTx

    Hybrid Surgery for Severe Mitral Valve Calcification: Limitations and Caveats for an Open Transcatheter Approach

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    Background and Objectives: Mitral stenosis with extensive mitral annular calcification (MAC) remains surgically challenging in respect to clinical outcome. Prolonged surgery time with imminent ventricular rupture and systolic anterior motion can be considered as a complex of causal factors. The aim of our alternative hybrid approach was to reduce the risk of annual rupture and paravalvular leaks and to avoid obstruction of the outflow tract. A review of the current literature was also carried out. Materials and Methods: Six female patients (mean age 76 +/- 9 years) with severe mitral valve stenosis and severely calcified annulus underwent an open implantation of an Edwards Sapien 3 prosthesis on cardiopulmonary bypass. Our hybrid approach involved resection of the anterior mitral leaflet, placement of anchor sutures and the deployment of a balloon expanded prosthesis under visual control. Concomitant procedures were carried out in three patients. Results: The mean duration of cross-clamping was 95 +/- 31 min and cardiopulmonary bypass was 137 +/- 60 min. The perioperative TEE showed in three patients an inconspicuous, heart valve-typical gradient on all implanted prostheses and a clinically irrelevant paravalvular leakage occurred in the anterior annulus. In the left ventricular outflow tract, mild to moderately elevated gradients were recorded. No adverse cerebrovascular events and pacemaker implantations were observed. All but one patient survived to discharge. Survival at one year was 83.3%. Conclusions: This off label implantation of the Edwards Sapien 3 prosthesis may be considered as a suitable bail-out approach for patients at high-risk for mitral valve surgery or deemed inoperable due to extensive MAC

    Stealth Galaxies in the Halo of the Milky Way

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    We predict that there is a population of low-luminosity dwarf galaxies orbiting within the halo of the Milky Way that have surface brightnesses low enough to have escaped detection in star-count surveys. The overall count of stealth galaxies is sensitive to the presence (or lack) of a low-mass threshold in galaxy formation. These systems have luminosities and stellar velocity dispersions that are similar to those of known ultrafaint dwarf galaxies but they have more extended stellar distributions (half light radii greater than about 100 pc) because they inhabit dark subhalos that are slightly less massive than their higher surface brightness counterparts. As a result, the typical peak surface brightness is fainter than 30 mag per square arcsec. One implication is that the inferred common mass scale for Milky Way dwarfs may be an artifact of selection bias. If there is no sharp threshold in galaxy formation at low halo mass, then ultrafaint galaxies like Segue 1 represent the high-mass, early forming tail of a much larger population of objects that could number in the hundreds and have typical peak circular velocities of about 8 km/s and masses within 300 pc of about 5 million solar masses. Alternatively, if we impose a low-mass threshold in galaxy formation in order to explain the unexpectedly high densities of the ultrafaint dwarfs, then we expect only a handful of stealth galaxies in the halo of the Milky Way. A complete census of these objects will require deeper sky surveys, 30m-class follow-up telescopes, and more refined methods to identify extended, self-bound groupings of stars in the halo.Comment: 12 pages, 7 figures, accepted by ApJ. Several crucial references added and the discussion has been expanded. Conclusions are unchanged

    Effect of fruiting-related genes on the formation of volatile organic compounds in the mushroom Schizophyllum commune

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    In fungi, little is known about connections between volatile organic compound (VOC) formation and developmental stages that are amongst others triggered by fruiting-related genes (FRGs). We analysed the volatilomes of Schizophyllum commune during different developmental stages in a variety of FRG-deletion strains and wild-type strains. The deletion strains Δtea1Δtea1, Δwc-2Δwc-2 and Δhom2Δhom2 were unable to develop fruiting bodies, and Δfst4Δfst4 formed only rudimentary fruiting body structures. Early developmental stages of these strains were dominated by esters, including methyl 2-methylbutanoate, ethyl 2-methylbutanoate, isobutyl 2-methylpropionate, and 2-methylbutyl acetate, of which the last three were not found in the headspace (HS) of the wild-type samples. Compared to the wild type, in the HS of hom2con samples, that are able to form fruiting bodies, methyl 2-methylbutanoate was the most abundant substance at early stages (68–81% of the total peak area). In contrast to fruiting body forming strains, Δtea1Δtea1, Δwc-2Δwc-2, Δhom2Δhom2 and Δfst4Δfst4 showed less sesquiterpenes in the HS. However, the sesquiterpenes found in the HS of FRG-deletion strains, namely, (E)-nerolidol, δ-cadinene, L-calamenene, α-bisabolol and β-bisabolene, were not present in hom2con or wild-type strains that mainly formed fruiting bodies and barely mycelium. Several sesquiterpenes, including α-guaiene, chamigrene and γ-gurjunene, were only found in presence of fruiting bodies. Our results show remarkable connections between FRGs, fruiting body development and VOC production in S. commune, especially counting for sesquiterpenes. Future studies are needed to reveal whether FRGs directly regulates VOC formation or indirectly by changing the phenotype

    Multi-Element Abundance Measurements from Medium-Resolution Spectra. III. Metallicity Distributions of Milky Way Dwarf Satellite Galaxies

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    We present metallicity distribution functions (MDFs) for the central regions of eight dwarf satellite galaxies of the Milky Way: Fornax, Leo I and II, Sculptor, Sextans, Draco, Canes Venatici I, and Ursa Minor. We use the published catalog of abundance measurements from the previous paper in this series. The measurements are based on spectral synthesis of iron absorption lines. For each MDF, we determine maximum likelihood fits for Leaky Box, Pre-Enriched, and Extra Gas (wherein the gas supply available for star formation increases before it decreases to zero) analytic models of chemical evolution. Although the models are too simplistic to describe any MDF in detail, a Leaky Box starting from zero metallicity gas fits none of the galaxies except Canes Venatici I well. The MDFs of some galaxies, particularly the more luminous ones, strongly prefer the Extra Gas Model to the other models. Only for Canes Venatici I does the Pre-Enriched Model fit significantly better than the Extra Gas Model. The best-fit effective yields of the less luminous half of our galaxy sample do not exceed 0.02 Z_sun, indicating that gas outflow is important in the chemical evolution of the less luminous galaxies. We surmise that the ratio of the importance of gas infall to gas outflow increases with galaxy luminosity. Strong correlations of average [Fe/H] and metallicity spread with luminosity support this hypothesis.Comment: 17 pages, 5 figures; accepted for publication in ApJ; minor corrections in v3; corrected typographical errors in Tables 1 and 3 in v
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