The effects of abdominal compartment hypertension after open and endovascular repair of a ruptured abdominal aortic aneurysm

ObjectiveThis study assessed if emergency endovascular repair (eEVR) reduces the increase in intra-abdominal compartment pressure and host inflammatory response in patients with ruptured abdominal aortic aneurysm (AAA).MethodsThirty patients with ruptured AAA were prospectively recruited. Patients were offered eEVR or emergency conventional open repair (eOR) depending on anatomic suitability. Intra-abdominal pressure was measured postoperatively, at 2 and 6 hours, and then daily for 5 days. Organ dysfunction was assessed preoperatively by calculating the Hardman score. Multiple organ dysfunction syndrome, systemic inflammatory response syndrome, and lung injury scores were calculated regularly postoperatively. Hematologic analyses included serum urea and electrolytes, liver function indices, and C-reactive protein. Urine was analyzed for the albumin-creatinine ratio.ResultsFourteen patients (12 men; mean age, 72.2 ± 6.2 years) underwent eEVR, and 16 (14 men; mean age, 71.4 ± 7.0 years) had eOR. Intra-abdominal pressure was significantly higher in the eOR cohort compared with the eEVR group. The eEVR patients had significantly less blood loss (P < .001) and transfused (P < .001) and total intraoperative intravenous fluid infusion (P = .001). The eOR group demonstrated a greater risk of organ dysfunction, with a higher systemic inflammatory response syndrome score at day 5 (P = .005) and higher lung injury scores at days 1 and 3 (P = .02 and P = .02) compared with eEVR. A significant correlation was observed between intra-abdominal pressure and the volume of blood lost and transfused, amount of fluid given, systemic inflammatory response syndrome score, multiple organ dysfunction score, lung injury score, and the length of stay in the intensive care unit and hospital.ConclusionThese results suggest that eEVR of ruptured AAA is less stressful and is associated with less intra-abdominal hypertension and host inflammatory response compared with eOR

Hamiltonian thermodynamics of a Lovelock black hole

We consider the Hamiltonian dynamics and thermodynamics of spherically symmetric spacetimes within a one-parameter family of five-dimensional Lovelock theories. We adopt boundary conditions that make every classical solution part of a black hole exterior, with the spacelike hypersurfaces extending from the horizon bifurcation three-sphere to a timelike boundary with fixed intrinsic metric. The constraints are simplified by a Kucha\v{r}-type canonical transformation, and the theory is reduced to its true dynamical degrees of freedom. After quantization, the trace of the analytically continued Lorentzian time evolution operator is interpreted as the partition function of a thermodynamical canonical ensemble. Whenever the partition function is dominated by a Euclidean black hole solution, the entropy is given by the Lovelock analogue of the Bekenstein-Hawking entropy; in particular, in the low temperature limit the system exhibits a dominant classical solution that has no counterpart in Einstein's theory. The asymptotically flat space limit of the partition function does not exist. The results indicate qualitative robustness of the thermodynamics of five-dimensional Einstein theory upon the addition of a nontrivial Lovelock term.Comment: 22 pages, REVTeX v3.

Suprarenal fixation of endovascular aortic stent grafts: assessment of medium-term to long-term renal function by analysis of juxtarenal stent morphology.

Objective: The effect of supra-renal stent fixation during endovascular aortic aneurysm repair (EVAR) on renal function remains unclear. Using a unique validated 3D intraluminal imaging technique, we analysed the effect of suprarenal stent position relative to renal artery orifices and its medium to long term effects on renal function.Methods: Thirty-four consecutive patients from a single institution were studied following EVAR using the Zenith endograft system from September 1999 to March 2002. The precise locations of the uncovered supra-renal stent struts were assessed by a virtual endoscopic imaging technique. Anatomical and quantitative categorisation of patients was made according to the configuration of uncovered stent struts across the renal artery ostia (RAO). The anatomical subgroups were defined as struts located centrally or peripherally across both RAO. The quantitative subgroups were defined as RAO crossed by multiple struts, a solitary strut or no struts. The subgroups were compared for their renal function as assessed by temporal measurements of serum creatinine concentration and creatinine clearance, and renal parenchymal perfusion defects as assessed using contrast-enhanced computerised tomography (CT).Results: Mean follow-up was 52.7 months. Separate subgroup analysis for both anatomical and quantitative configurations did not demonstrate any significant difference in renal function between the different strut permutations (p&gt;0.05). Follow-up imaging confirmed one case of renal infarction secondary to an occluded accessory renal artery, although, this patient had normal creatinine levels.Conclusion: RAO coverage by supra-renal uncovered stents does not appear to have a significant effect on renal function as evaluated by creatinine measurements in patients with normal pre-operative renal function

Absolute conservation law for black holes

In all 2d theories of gravity a conservation law connects the (space-time dependent) mass aspect function at all times and all radii with an integral of the matter fields. It depends on an arbitrary constant which may be interpreted as determining the initial value together with the initial values for the matter field. We discuss this for spherically reduced Einstein-gravity in a diagonal metric and in a Bondi-Sachs metric using the first order formulation of spherically reduced gravity, which allows easy and direct fixations of any type of gauge. The relation of our conserved quantity to the ADM and Bondi mass is investigated. Further possible applications (ideal fluid, black holes in higher dimensions or AdS spacetimes etc.) are straightforward generalizations.Comment: LaTex, 17 pages, final version, to appear in Phys. Rev.

Hamiltonian thermodynamics of the Reissner-Nordstr\"om-anti-de Sitter black hole

We consider the Hamiltonian dynamics and thermodynamics of spherically symmetric Einstein-Maxwell spacetimes with a negative cosmological constant. We impose boundary conditions that enforce every classical solution to be an exterior region of a Reissner-Nordstr\"om-anti-de Sitter black hole with a nondegenerate Killing horizon, with the spacelike hypersurfaces extending from the horizon bifurcation two-sphere to the asymptotically anti-de Sitter infinity. The constraints are simplified by a canonical transformation, which generalizes that given by Kucha\v{r} in the spherically symmetric vacuum Einstein theory, and the theory is reduced to its true dynamical degrees of freedom. After quantization, the grand partition function of a thermodynamical grand canonical ensemble is obtained by analytically continuing the Lorentzian time evolution operator to imaginary time and taking the trace. A~similar analysis under slightly modified boundary conditions leads to the partition function of a thermodynamical canonical ensemble. The thermodynamics in each ensemble is analyzed, and the conditions that the (grand) partition function be dominated by a classical Euclidean black hole solution are found. When these conditions are satisfied, we recover in particular the Bekenstein-Hawking entropy. The limit of a vanishing cosmological constant is briefly discussed. (This paper is dedicated to Karel Kucha\v{r} on the occasion of his sixtieth birthday.)Comment: 34 pages, REVTeX v3.0. (Minor corrections and presentational revisions; added references.

Reduced phase space formalism for spherically symmetric geometry with a massive dust shell

We perform a Hamiltonian reduction of spherically symmetric Einstein gravity with a thin dust shell of positive rest mass. Three spatial topologies are considered: Euclidean (R^3), Kruskal (S^2 x R), and the spatial topology of a diametrically identified Kruskal (RP^3 - {a point at infinity}). For the Kruskal and RP^3 topologies the reduced phase space is four-dimensional, with one canonical pair associated with the shell and the other with the geometry; the latter pair disappears if one prescribes the value of the Schwarzschild mass at an asymptopia or at a throat. For the Euclidean topology the reduced phase space is necessarily two-dimensional, with only the canonical pair associated with the shell surviving. A time-reparametrization on a two-dimensional phase space is introduced and used to bring the shell Hamiltonians to a simpler (and known) form associated with the proper time of the shell. An alternative reparametrization yields a square-root Hamiltonian that generalizes the Hamiltonian of a test shell in Minkowski space with respect to Minkowski time. Quantization is briefly discussed. The discrete mass spectrum that characterizes natural minisuperspace quantizations of vacuum wormholes and RP^3-geons appears to persist as the geometrical part of the mass spectrum when the additional matter degree of freedom is added.Comment: 36 pages, REVTeX v3.1 with amsfonts. (References updated; minor typos corrected.

The Atacama Cosmology Telescope: Cosmological parameters from three seasons of data

We present constraints on cosmological and astrophysical parameters from high-resolution microwave background maps at 148 GHz and 218 GHz made by the Atacama Cosmology Telescope (ACT) in three seasons of observations from 2008 to 2010. A model of primary cosmological and secondary foreground parameters is fit to the map power spectra and lensing deflection power spectrum, including contributions from both the thermal Sunyaev-Zeldovich (tSZ) effect and the kinematic Sunyaev-Zeldovich (kSZ) effect, Poisson and correlated anisotropy from unresolved infrared sources, radio sources, and the correlation between the tSZ effect and infrared sources. The power ell^2 C_ell/2pi of the thermal SZ power spectrum at 148 GHz is measured to be 3.4 +\- 1.4 muK^2 at ell=3000, while the corresponding amplitude of the kinematic SZ power spectrum has a 95% confidence level upper limit of 8.6 muK^2. Combining ACT power spectra with the WMAP 7-year temperature and polarization power spectra, we find excellent consistency with the LCDM model. We constrain the number of effective relativistic degrees of freedom in the early universe to be Neff=2.79 +\- 0.56, in agreement with the canonical value of Neff=3.046 for three massless neutrinos. We constrain the sum of the neutrino masses to be Sigma m_nu < 0.39 eV at 95% confidence when combining ACT and WMAP 7-year data with BAO and Hubble constant measurements. We constrain the amount of primordial helium to be Yp = 0.225 +\- 0.034, and measure no variation in the fine structure constant alpha since recombination, with alpha/alpha0 = 1.004 +/- 0.005. We also find no evidence for any running of the scalar spectral index, dns/dlnk = -0.004 +\- 0.012.Comment: 26 pages, 22 figures. This paper is a companion to Das et al. (2013) and Dunkley et al. (2013). Matches published JCAP versio