University of Milano-Bicocca

About: University of Milano-Bicocca is a education organization based out in Milan, Italy. It is known for research contribution in the topics: Population & Blood pressure. The organization has 8972 authors who have published 22322 publications receiving 620484 citations. The organization is also known as: Università degli Studi di Milano-Bicocca & Universita degli Studi di Milano-Bicocca.

The Prompt-afterglow Connection in Gamma-ray Bursts: a Comprehensive Statistical Analysis of Swift X-ray Light-curves

Abstract: We present a comprehensive statistical analysis of Swift X-ray light-curves of Gamma- Ray Bursts (GRBs) collecting data from more than 650 GRBs discovered by Swift and other facilities. The unprecedented sample size allows us to constrain the rest-frame X-ray properties of GRBs from a statistical perspective, with particular reference to intrinsic time scales and the energetics of the different light-curve phases in a common rest-frame 0.3-30 keV energy band. Temporal variability episodes are also studied and their properties constrained. Two fundamental questions drive this effort: i) Does the X-ray emission retain any kind of "memory" of the prompt γ-ray phase? ii) Where is the dividing line between long and short GRB X-ray properties? We show that short GRBs decay faster, are less luminous and less energetic than long GRBs in the X-rays, but are interestingly characterized by similar intrinsic absorption. We furthermore reveal the existence of a number of statistically significant relations that link the X-ray to prompt γ-ray parameters in long GRBs; short GRBs are outliers of the majority of these 2-parameter relations. However and more importantly, we report on the existence of a universal 3-parameter scaling that links the X-ray and the γ-ray energy to the prompt spectral peak energy of both long and short GRBs: E(sub X,iso)∝ E(sup 1.00+/-0.06)(sub γ,iso) /E(sup 0.60+/-0.10)(sub pk).

Prediction of right ventricular failure after ventricular assist device implant: systematic review and meta-analysis of observational studies

Abstract: Right ventricular failure (RVF) after left ventricular assist device (LVAD) implantation is associated with increased morbidity and mortality, but the identification of LVAD candidates at risk for RVF remains challenging. We undertook a systematic review and meta-analysis of observational studies of risk factors associated with RVF after LVAD implant. Thirty-six studies published between 1 January 1995 and 30 April 2015, comprising 995 RVF patients out of a pooled final population of 4428 patients, were identified. Meta-analysed prevalence of post-LVAD RVF was 35%. A need for mechanical ventilation [odds ratio (OR) 2.99], or continuous renal replacement therapy (CRRT; OR 4.61, area under the curve 0.78, specificity 0.91) were the clinical variables with the highest effect size (ES) in predicting RVF. International normalized ratio [INR; standardized mean difference (SMD) 0.49] and N-terminal pro-brain natriuretic peptide (NT-proBNP) (SMD 0.52) were the biochemical markers that best discriminated between RVF and No-RVF populations, though NT-proBNP was highly heterogeneous. Right ventricular stroke work index (RVSWI) and central venous pressure (CVP) (SMD -0.58 and 0.47, respectively) were the haemodynamic measures with the highest ES in identifying patients at risk of post-LVAD RVF; CVP was particularly useful in risk stratifying patients undergoing continuous-flow LVAD implant (SMD 0.59, P < 0.001, I2 = 20.9%). Finally, pre-implant moderate to severe right ventricular (RV) dysfunction, as assessed qualitatively (OR 2.82), or a greater RV/LV diameter ratio (SMD 0.51) were the standard echocardiographic measurements with the highest ES in comparing RVF with No-RVF patients. Longitudinal systolic strain of the RV free wall had the highest ES (SMD 0.73) but also the greatest heterogeneity (I2 = 74%) and was thus only marginally significant (P = 0.05). Patients on ventilatory support or CRRT are at high risk for post-LVAD RVF, similarly to patients with slightly increased INR, high NT-proBNP or leukocytosis. High CVP, low RVSWI, an enlarged right ventricle with concomitant low RV strain also identify patients at higher risk.