Incidenza, cause e predittori di reospedalizzazione in pazienti sottoposti ad impianto transcatetere di valvola aortica

La frequenza, le cause e i predittori di reospedalizzazione dopo impianto transcatetere di valvola aortica sono stati analizzati in una popolazione di 900 pazienti inclusi nel Bern TAVI Registry tra Agosto 2007 e Giugno 2014. Di 868 pazienti vivi alla dimissione, 221 (25.4%)hanno avuto almeno una nuova ospedalizzazione entro un anno dalla procedura. Rispetto ai pazienti non reospedalizzati, quelli reospedalizzati erano piu frequentemente di sesso maschile, con fibrillazione atriale e piu alti livelli di creatinina plasmatica. Il numero totale di reospedalizzazioni è stato 308, di cui il 46.1% per cause cardiovascolari; le cause non cardiovascolari erano rappresentate da interventi chirugici (11.7%), disturbi gastrointestinali (9.7%), cancro (4.9%), malattie respiratorie (4.6%) e mallatie renali croniche (2.6%). Il sesso maschile e l'insufficienza renale acuta (stadio 3 secondo i criteri VARC2) sono risultati predittori indipendenti di reospedalizzazione per tutte le cause; un pregresso infarto del miocardio e l'occorrenza di un sanguinamento maggiore nel periodo peri-procedurale erano associati con un piu alto rischio di reospedalizzazione per cause cardiovascolari. Il rischio di mortalità è risultato significativamente aumentato nei soggetti reospedalizzati

A parallel solver for reaction-diffusion systems in computational electrocardiology

In this work, a parallel three-dimensional solver for numerical simulations in computational electrocardiology is introduced and studied. The solver is based on the anisotropic Bidomain %(AB) cardiac model, consisting of a system of two degenerate parabolic reaction-diffusion equations describing the intra and extracellular potentials of the myocardial tissue. This model includes intramural fiber rotation and anisotropic conductivity coefficients that can be fully orthotropic or axially symmetric around the fiber direction. %In case of equal anisotropy ratio, this system reduces to The solver also includes the simpler anisotropic Monodomain model, consisting of only one reaction-diffusion equation. These cardiac models are coupled with a membrane model for the ionic currents, consisting of a system of ordinary differential equations that can vary from the simple FitzHugh-Nagumo (FHN) model to the more complex phase-I Luo-Rudy model (LR1). The solver employs structured isoparametric $Q_1$ finite elements in space and a semi-implicit adaptive method in time. Parallelization and portability are based on the PETSc parallel library. Large-scale computations with up to $O(10^7)$ unknowns have been run on parallel computers, simulating excitation and repolarization phenomena in three-dimensional domains

Modeling Ventricular Excitation : axial and orthotropic anisotropy effects on wavefronts and potentials.

By applying the eikonal approximation to the bidomain model of the cardiac tissue we investigate the influence of the axially isotropic and orthotropic conductivity tensors on the propagation of the excitation wave fronts and on the associated potential distribution and electrograms

Ocular manifestations in Gorlin-Goltz syndrome

Background: Gorlin-Goltz syndrome, also known as nevoid basal cell carcinoma syndrome, is a rare genetic disorder that is transmitted in an autosomal dominant manner with complete penetrance and variable expressivity. It is caused in 85% of the cases with a known etiology by pathogenic variants in the PTCH1 gene, and is characterized by a wide range of developmental abnormalities and a predisposition to multiple neoplasms. The manifestations are multiple and systemic and consist of basal cell carcinomas in various regions, odontogenic keratocistic tumors and skeletal anomalies, to name the most frequent. Despite the scarce medical literature on the topic, ocular involvement in this syndrome is frequent and at the level of various ocular structures. Our study focuses on the visual apparatus and its annexes in subjects with this syndrome, in order to better understand how this syndrome affects the ocular system, and to evaluate with greater accuracy and precision the nature of these manifestations in this group of patients. Results: Our study confirms the presence of the commonly cited ocular findings in the general literature regarding the syndrome [hypertelorism (45.5%), congenital cataract (18%), nystagmus (9%), colobomas (9%)] and highlights strabismus (63% of the patients), epiretinal membranes (36%) and myelinated optic nerve fiber layers (36%) as the most frequent ophthalmological findings in this group of patients. Conclusions: The presence of characteristic and frequent ocular signs in the Gorlin- Goltz syndrome could help with the diagnostic process in subjects suspected of having the syndrome who do not yet have a diagnosis. The ophthalmologist has a role as part of a multidisciplinary team in managing these patients. The ophthalmological follow-up that these patients require, can allow, if necessary, a timely therapy that could improve the visual prognosis of such patients

Treatment plan comparison in acute and chronic respiratory tract diseases : an observational study of doxophylline vs. theophylline

BACKGROUND: The main objective of this article is to estimate the global cost related to the use of the two drugs (associated drugs, specialist visits, hospital admissions, plasma drug monitoring). METHODS: The drug prescriptions were extracted from the Information System of the Pharmaceutical Prescriptions of the Marche Region for each ATC code in the years 2008-2012 and the number of patients per year and other outcomes measure were obtained. RESULTS: 13,574 patients were treated with theophylline and 19,426 patients with doxophylline. The number of patients treated was approximately 5,000 per year. Co-prescription with other drugs, use of corticosteroids, mean number of visits and hospital admissions (per 100 patients) were lower for doxophylline vs theophylline (1.55vs5.50, 0.3vs0.7, 2.05vs3.73 and 1.57vs3.3 respectively). The annual mean cost per patient was €187.4 for those treated with doxophylline and €513.5 for theophylline. CONCLUSIONS: In our study, doxophylline resulted to be associated with a reduction of the overall cost

A variational Bayesian method for inverse problems with impulsive noise

We propose a novel numerical method for solving inverse problems subject to impulsive noises which possibly contain a large number of outliers. The approach is of Bayesian type, and it exploits a heavy-tailed t distribution for data noise to achieve robustness with respect to outliers. A hierarchical model with all hyper-parameters automatically determined from the given data is described. An algorithm of variational type by minimizing the Kullback-Leibler divergence between the true posteriori distribution and a separable approximation is developed. The numerical method is illustrated on several one- and two-dimensional linear and nonlinear inverse problems arising from heat conduction, including estimating boundary temperature, heat flux and heat transfer coefficient. The results show its robustness to outliers and the fast and steady convergence of the algorithm.Comment: 20 pages, to appear in J. Comput. Phy

Incorporating Inductances in Tissue-Scale Models of Cardiac Electrophysiology

In standard models of cardiac electrophysiology, including the bidomain and monodomain models, local perturbations can propagate at infinite speed. We address this unrealistic property by developing a hyperbolic bidomain model that is based on a generalization of Ohm's law with a Cattaneo-type model for the fluxes. Further, we obtain a hyperbolic monodomain model in the case that the intracellular and extracellular conductivity tensors have the same anisotropy ratio. In one spatial dimension, the hyperbolic monodomain model is equivalent to a cable model that includes axial inductances, and the relaxation times of the Cattaneo fluxes are strictly related to these inductances. A purely linear analysis shows that the inductances are negligible, but models of cardiac electrophysiology are highly nonlinear, and linear predictions may not capture the fully nonlinear dynamics. In fact, contrary to the linear analysis, we show that for simple nonlinear ionic models, an increase in conduction velocity is obtained for small and moderate values of the relaxation time. A similar behavior is also demonstrated with biophysically detailed ionic models. Using the Fenton-Karma model along with a low-order finite element spatial discretization, we numerically analyze differences between the standard monodomain model and the hyperbolic monodomain model. In a simple benchmark test, we show that the propagation of the action potential is strongly influenced by the alignment of the fibers with respect to the mesh in both the parabolic and hyperbolic models when using relatively coarse spatial discretizations. Accurate predictions of the conduction velocity require computational mesh spacings on the order of a single cardiac cell. We also compare the two formulations in the case of spiral break up and atrial fibrillation in an anatomically detailed model of the left atrium, and [...].Comment: 20 pages, 12 figure

The establishment of Central American migratory corridors and the biogeographic origins of seasonally dry tropical forests in Mexico

Biogeography and community ecology can mutually illuminate the formation of a regional species pool or biome. Here, we apply phylogenetic methods to a large and diverse plant clade, Malpighiaceae, to characterize the formation of its species pool in Mexico, and its occupancy of the seasonally dry tropical forest (SDTF) biome that occurs there. We find that the ~162 species of Mexican Malpighiaceae represent ~33 dispersals from South America beginning in the Eocene and continuing until the Pliocene (~46.4–3.8 Myr). Furthermore, dispersal rates between South America and Mexico show a significant six-fold increase during the mid-Miocene (~23.9 Myr). We hypothesize that this increase marked the availability of Central America as an important corridor for Neotropical plant migration. We additionally demonstrate that this high rate of dispersal contributed substantially more to the phylogenetic diversity of Malpighiaceae in Mexico than in situ diversification. Finally, we show that most lineages arrived in Mexico pre-adapted with regard to one key SDTF trait, total annual precipitation. In contrast, these lineages adapted to a second key trait, precipitation seasonality, in situ as mountain building in the region gave rise to the abiotic parameters of extant SDTF. The timing of this in situ adaptation to seasonal precipitation suggests that SDTF likely originated its modern characteristics by the late Oligocene, but was geographically more restricted until its expansion in the mid-Miocene. These results highlight the complex interplay of dispersal, adaptation, and in situ diversification in the formation of tropical biomes. Our results additionally demonstrate that these processes are not static, and their relevance can change markedly over evolutionary time. This has important implications for understanding the origin of SDTF in Mexico, but also for understanding the temporal and spatial origin of biomes and regional species pools more broadly

Isogeometric approximation of cardiac electrophysiology models on surfaces: An accuracy study with application to the human left atrium

We consider Isogeometric Analysis in the framework of the Galerkin method for the spatial approximation of cardiac electrophysiology models defined on NURBS surfaces; specifically, we perform a numerical comparison between basis functions of degree p ≥ 1 and globally C k -continuous, with k = 0 or p − 1, to find the most accurate approximation of a propagating front with the minimal number of degrees of freedom. We show that B-spline basis functions of degree p ≥ 1, which are C p−1 -continuous capture accurately the front velocity of the transmembrane potential even with moderately refined meshes; similarly, we show that, for accurate tracking of curved fronts, high-order continuous B-spline basis functions should be used. Finally, we apply Isogeometric Analysis to an idealized human left atrial geometry described by NURBS with physiologically sound fiber directions and anisotropic conductivity tensor to demonstrate that the numerical scheme retains its favorable approximation properties also in a more realistic setting

Ankle/brachial index to everyone.

In the last years significant attention has been paid in identifying markers of subclinical atherosclerosis or of increased cardiovascular risk. Method An abnormal ankle/brachial index (ABI) identifies patients affected by lower extremity peripheral arterial disease, and even more important, represents a powerful predictor of the development of future ischemic cardiovascular events. Conclusions In our opinion, ABI is a cardiovascular risk prediction tool with very desirable properties that might become a routine measurement in clinical practice