Economic analysis of endovascular repair versus surveillance for patients with small abdominal aortic aneurysms

BackgroundThe Positive Impact of EndoVascular Options for Treating Aneurysms Early (PIVOTAL) trial enrolled individuals with small (4.0- to 5.0-cm diameter) abdominal aortic aneurysms (AAA) and reported no difference in rupture or aneurysm-related death for patients who received early endovascular repair (EVAR) vs surveillance with serial imaging studies. We evaluated resource use, medical cost, and quality of life outcomes associated with the PIVOTAL treatment strategies.MethodsThis prospective economic and quality of life study was conducted within a randomized trial, with PIVOTAL sites participating in the quality of life (n = 67) and economic (n = 63) studies. The PIVOTAL trial randomized 728 patients (366 early EVAR and 362 surveillance). We used information from 701 quality of life (351 early EVAR and 350 surveillance) and 614 economic (314 early EVAR and 300 surveillance) study participants enrolled in the PIVOTAL trial. The main outcome measures were total medical costs and the aneurysm repair rate at 48 months.ResultsAfter 6 months, the rate of aneurysm repair was 96 vs 10 per 100 patients in the early EVAR and surveillance groups, respectively (difference, 86; 95% confidence interval [CI], 82-90; P < .0001), and total medical costs were greater in the early EVAR group ($33,471 vs$5520; difference, $27,951; 95$25,156-$30,746; P < .0001). In months 7 through 48, however, the rate of aneurysm repair was 54 per 100 patients in the surveillance group, and total medical costs were higher for patients in the surveillance vs the early EVAR group ($40,592 vs $15,197; difference,$25,394; 95% CI, $15,184-$35,605; P < .0001). At 48 months' follow-up, early EVAR patients had greater cumulative use of AAA repair (97 vs 64 per 100 patients; difference, 34; 95% CI, 21-46; P < .0001), but there was no difference in total medical costs ($48,669 vs$46,112; difference, $2557; 95$8043 to $13,156; P = .64). After discounting at 3$47,765 vs $43,532; difference, 4232; 95$5561 to $14,025; P = .40). There were no treatment-related differences in quality of life at 24 months.ConclusionsA treatment strategy involving early repair of smaller AAA with EVAR is associated with no difference in total medical costs at 48 months vs surveillance with serial imaging studies. Longer follow-up is required to determine whether the late medical cost increases observed for surveillance will persist beyond 48 months

The Santa Fe Light Cone Simulation Project: II. The Prospects for Direct Detection of the WHIM with SZE Surveys

Detection of the Warm-Hot Intergalactic Medium (WHIM) using Sunyaev-Zeldovich effect (SZE) surveys is an intriguing possibility, and one that may allow observers to quantify the amount of "missing baryons" in the WHIM phase. We estimate the necessary sensitivity for detecting low density WHIM gas with the South Pole Telescope (SPT) and Planck Surveyor for a synthetic 100 square degree sky survey. This survey is generated from a very large, high dynamic range adaptive mesh refinement cosmological simulation performed with the Enzo code. We find that for a modest increase in the SPT survey sensitivity (a factor of 2-4), the WHIM gas makes a detectable contribution to the integrated sky signal. For a Planck-like satellite, similar detections are possible with a more significant increase in sensitivity (a factor of 8-10). We point out that for the WHIM gas, the kinematic SZE signal can sometimes dominate the thermal SZE where the thermal SZE decrement is maximal (150 GHz), and that using the combination of the two increases the chance of WHIM detection using SZE surveys. However, we find no evidence of unique features in the thermal SZE angular power spectrum that may aid in its detection. Interestingly, there are differences in the power spectrum of the kinematic SZE, which may not allow us to detect the WHIM directly, but could be an important contaminant in cosmological analyses of the kSZE-derived velocity field. Corrections derived from numerical simulations may be necessary to account for this contamination.Comment: 9 pages, submitted to Astrophysical Journa

The UCSD shortness of breath questionnaire has longitudinal construct validity in idiopathic pulmonary fibrosis

SummaryBackgroundIdiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease that often causes disabling dyspnea. In IPF and other lung diseases, patient-reported outcomes (PROs)—questionnaires designed to gather information from the patient's perspective—can determine whether therapies affect dyspnea or other outcomes meaningful to patients. Before a PRO can be used confidently as an outcome measure in a longitudinal trial, studies must demonstrate the PRO's ability to capture change over time in the target population. Our goal in this study was to examine whether the UCSD Shortness of Breath Questionnaire does so in patients with IPF.MethodsWe used data from the Sildenafil Trial of Exercise Performance in Idiopathic Pulmonary Fibrosis (STEP-IPF) to perform analyses that examined associations between UCSD scores and five external measures (anchors) at baseline and over time. Anchors included the Activity domain from St. George's Respiratory Questionnaire (SGRQ-A), the Physical Functioning domain from the SF-36 (SF36-PF), forced vital capacity (FVC), diffusing capacity of the lung for carbon monoxide (DLCO), and distance walked during a timed walk test (6MWD). Linear regression models were used to examine relationships between UCSD scores and anchors over time.ResultsAt baseline, UCSD scores were weakly correlated with percent predicted FVC (−0.21, p = 0.005) and percent predicted DLCO (−0.20, p = 0.008), moderately correlated with 6MWD (−0.39, p < 0.0001) and strongly correlated with SGRQ-A (0.79, p < 0.0001) and SF36-PF (−0.72, p < 0.0001). Change over time in UCSD scores was associated with change in FVC (estimate = 2.54, standard error [SE] = 1.23, p = 0.04), SGRQ-A (estimate = 7.94, SE = 1.11, p < 0.0001), SF36-PF (estimate = 6.00, SE = 1.13, p < 0.0001), and 6MWD (estimate = 4.23, SE = 1.18, p = 0.0004) but not DLCO (estimate = 0.33, SE = 1.33, p = 0.80).ConclusionsThese results support the validity of the UCSD to assess change in dyspnea over time in patients with IPF

The Properties of X-ray Cold Fronts in a Statistical Sample of Simulated Galaxy Clusters

We examine the incidence of cold fronts in a large sample of galaxy clusters extracted from a (512h^-1 Mpc) hydrodynamic/N-body cosmological simulation with adiabatic gas physics computed with the Enzo adaptive mesh refinement code. This simulation contains a sample of roughly 4000 galaxy clusters with M > 10^14 M_sun at z=0. For each simulated galaxy cluster, we have created mock 0.3-8.0 keV X-ray observations and spectroscopic-like temperature maps. We have searched these maps with a new automated algorithm to identify the presence of cold fronts in projection. Using a threshold of a minimum of 10 cold front pixels in our images, corresponding to a total comoving length L_cf > 156h^-1 kpc, we find that roughly 10-12% of all projections in a mass-limited sample would be classified as cold front clusters. Interestingly, the fraction of clusters with extended cold front features in our synthetic maps of a mass-limited sample trends only weakly with redshift out to z=1.0. However, when using different selection functions, including a simulated flux limit, the trending with redshift changes significantly. The likelihood of finding cold fronts in the simulated clusters in our sample is a strong function of cluster mass. In clusters with M>7.5x10^14 M_sun the cold front fraction is 40-50%. We also show that the presence of cold fronts is strongly correlated with disturbed morphology as measured by quantitative structure measures. Finally, we find that the incidence of cold fronts in the simulated cluster images is strongly dependent on baryonic physics.Comment: 16 pages, 21 figures, Accepted to Ap

The Ground State of a Two-Dimensional Electron Liquid in a Weak Magnetic Field

We study the ground state of a clean two-dimensional electron liquid in a weak magnetic field where $N \gg 1$ lower Landau levels are completely filled and the upper level is partially filled. It is shown that the electrons at the upper Landau level form domains with filling factor equal to one and zero. The domains alternate with a spatial period of the order of the cyclotron radius, which is much larger than the interparticle distance at the upper Landau level. The one-particle density of states, which can be probed by tunneling experiments, is shown to have a pseudogap linearly dependent on the magnetic field in the limit of large $N$.Comment: REVTeX, 21 pages + 12 figures in PostScript. Uses amsfonts.sty, multicol.sty, and psfig.st

Anomalous tunneling conductances of a spin singlet \nu=2/3 edge states: Interplay of Zeeman splitting and Long Range Coulomb Interaction

The point contact tunneling conductance between edges of the spin singlet $\nu=2/3,\hat{K}=(3/3/0)$ quantum Hall states is studied both in the quasiparticle tunneling picture and in the electron tunneling picture. Due to the interplay of Zeeman splitting and the long range Coulomb interaction between edges of opposite chirality novel spin excitations emerge, and their effect is characterized by anomalous exponents of the charge and spin tunneling conductances in various temperature ranges. Depending on the kinds of scatterings at the point contact and the tunneling mechanism the anomalous interaction in spin sector may enhance or suppress the tunneling conductances. The effects of novel spin excitation are also relevant to the recent NMR experiments on quantum Hall edges.Comment: Revtex File, 7 pages: To be published in Physical Reviews

SDSS J092455.87+021924.9: an Interesting Gravitationally Lensed Quasar from the Sloan Digital Sky Survey

We report the discovery of a new gravitationally lensed quasar from the Sloan Digital Sky Survey, SDSS J092455.87+021924.9 (SDSS J0924+0219). This object was selected from among known SDSS quasars by an algorithm that was designed to select another known SDSS lensed quasar (SDSS 1226-0006A,B). Five separate components, three of which are unresolved, are identified in photometric follow-up observations obtained with the Magellan Consortium's 6.5m Walter Baade telescope at Las Campanas Observatory. Two of the unresolved components (designated A and B) are confirmed to be quasars with z=1.524; the velocity difference is less than 100 km sec^{-1} according to spectra taken with the W. M. Keck Observatory's Keck II telescope on Mauna Kea. A third stellar component, designated C, has the colors of a quasar with redshift similar to components A and B. The maximum separation of the point sources is 1.78". The other two sources, designated G and D, are resolved. Component G appears to be the best candidate for the lensing galaxy. Although component D is near the expected position of the fourth lensed component in a four image lens system, its properties are not consistent with being the image of a quasar at z~1.5. Nevertheless, the identical redshifts of components A and B and the presence of component C strongly suggest that this object is a gravitational lens. Our observations support the idea that a foreground object reddens the fourth lensed component and that another unmodeled effect (such as micro- or milli-lensing) demagnificates it, but we cannot rule out the possibility that SDSS0924+0219 is an example of the relatively rare class of ``three component'' lens systems.Comment: 24 pages, 6 figures, accepted by A

Quantum-Hall Quantum-Bits

Bilayer quantum Hall systems can form collective states in which electrons exhibit spontaneous interlayer phase coherence. We discuss the possibility of using bilayer quantum dot many-electron states with this property to create two-level systems that have potential advantages as quantum bits.Comment: 4 pages, 4 figures included, version to appear in Phys. Rev. B (Rapid Communications

The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey : cosmological implications of the full shape of the clustering wedges in the data release 10 and 11 galaxy samples

We explore the cosmological implications of the angle-averaged correlation function, ξ(s), and the clustering wedges, ξ⊥(s) and ξ∥(s), of the LOWZ and CMASS galaxy samples from Data Releases 10 and 11 of the Sloan Digital Sky Survey III (SDSS-III) Baryon Oscillation Spectroscopic Survey. Our results show no significant evidence for a deviation from the standard Λ cold dark matter model. The combination of the information from our clustering measurements with recent data from the cosmic microwave background is sufficient to constrain the curvature of the Universe to Ωk = 0.0010 ± 0.0029, the total neutrino mass to ∑mν < 0.23 eV (95 per cent confidence level), the effective number of relativistic species to Neff = 3.31 ± 0.27 and the dark energy equation of state to wDE = −1.051 ± 0.076. These limits are further improved by adding information from Type Ia supernovae and baryon acoustic oscillations from other samples. In particular, this data set combination is completely consistent with a time-independent dark energy equation of state, in which case we find wDE = −1.024 ± 0.052. We explore the constraints on the growth rate of cosmic structures assuming f(z) = Ωm(z)γ and obtain γ = 0.69 ± 0.15, consistent with the predictions of general relativity of γ = 0.55.Publisher PDFPeer reviewe