Active optics system of the VLT Survey Telescope.

This paper describes the active optics system of the VLT Survey Telescope, the 2.6-m survey telescope designed for visible wavelengths of the European Southern Observatory at Cerro Paranal, in the Atacama desert. The telescope is characterized by a wide field of view (1.42 deg diameter), leading to tighter active optics than in conventional telescopes, in particular for the alignment requirements. We discuss the effects of typical error sources on the image quality and present the specific solutions adopted for wavefront sensing and correction of the aberrations, which are based on the shaping of a monolithic primary mirror and the positioning of the secondary in five degrees of freedom.

Treatment of right ventricular outflow tract dysfunction: a multimodality approach.

The right timing to replace the pulmonary valve in a patient with dysfunction of the right ventricular outflow tract is unknown. Both percutaneous pulmonary valve and surgical prosthesis are suitable options. In every patient, the right ventricle (RV) remodels and recovers differently after pulmonary replacement. Therefore, it is difficult to identify the best treatment option and to predict the long-term results. In the last few years, we focused our research on optimizing the characterization of these patients through advanced cardiovascular imaging in order to find possible variables, parameters, and reproducible measurements that can help us in the decision-making process. The aim of the present article is to present our ongoing research lines that focus on the characterization and optimal treatment approach to the dysfunction of the RVOT.

Calibrating the interaction matrix for the LINC-NIRVANA high layer wavefront sensor.

LINC-NIRVANA is a near-infrared Fizeau interferometric imager that will operate at the Large Binocular Telescope. In preparation for the commissioning of this instrument, we conducted experiments for calibrating the high-layer wavefront sensor of the layer-oriented multi-conjugate adaptive optics system. For calibrating the multi-pyramid wavefront sensor, four light sources were used to simulate guide stars. Using this setup, we developed the push-pull method for calibrating the interaction matrix. The benefits of this method over the traditional push-only method are quantified, and also the effects of varying the number of push-pull frames over which aberrations are averaged is reported. Finally, we discuss a method for measuring mis-conjugation between the deformable mirror and the wavefront sensor, and the proper positioning of the wavefront sensor detector with respect to the four pupil positions.

Removing static aberrations from the active optics system of a wide-field telescope.

The wavefront sensor in active and adaptive telescopes is usually not in the optical path toward the scientific detector. It may generate additional wavefront aberrations, which have to be separated from the errors due to the telescope optics. The aberrations that are not rotationally symmetric can be disentangled from the telescope aberrations by a series of measurements taken in the center of the field, with the wavefront sensor at different orientation angles with respect to the focal plane. This method has been applied at the VLT Survey Telescope on the ESO Paranal observatory.

First laboratory results with the LINC-NIRVANA high layer wavefront sensor.

In the field of adaptive optics, multi-conjugate adaptive optics (MCAO) can greatly increase the size of the corrected field of view (FoV) and also extend sky coverage. By applying layer oriented MCAO (LO-MCAO) [4], together with multiple guide stars (up to 20) and pyramid wavefront sensors [7], LINC-NIRVANA (L-N for short) [1] will provide two AO-corrected beams to a Fizeau interferometer to achieve 10 milliarcsecond angular resolution on the Large Binocular Telescope. This paper presents first laboratory results of the AO performance achieved with the high layer wavefront sensor (HWS). This sensor, together with its associated deformable mirror (a Xinetics-349), is being operated in one of the L-N laboratories. AO reference stars, spread across a 2 arc-minute FoV and with aberrations resulting from turbulence introduced at specific layers in the atmosphere, are simulated in this lab environment. This is achieved with the Multi-Atmosphere Phase screen and Stars (MAPS) [2] unit. From the wavefront data, the approximate residual wavefront error after correction has been calculated for different turbulent layer altitudes and wind speeds. Using a somewhat undersampled CCD, the FWHM of stars in the nearly 2 arc-minute FoV has also been measured. These test results demonstrate that the high layer wavefront sensor of LINC-NIRVANA will be able to achieve uniform AO correction across a large FoV.

Right and left ventricular strain and strain rate in young adults before and after percutaneous atrial septal defect closure.

To evaluate acute change of right and left ventricle after percutaneous closure of isolated atrial septal defect (ASD) 21 adult patients (13 F; 8 M) aged 28 ± 9.5 range 18-49 years have been examined by echocardiography before and 24 hours after percutaneous closure of ASD. Twenty-one normal adult subjects, as control group were included. A MyLab25 echo machine equipped with a multifrequency 2.5-3.5 MHz transducer was used. Offline computer-based analysis for strain and SR were performed using XStrain software based on a feature tracking algorithm. All patients had ASD OS2 with right ventricular dilatation and diastolic areas were larger than in controls: P = 0.0158. Global right ventricular longitudinal strain was higher P = 0.0438. Twenty-four hours after ASD closure, right ventricular diastolic and systolic areas were significantly reduced. Right ventricular global longitudinal systolic strain decreased: P = 0.00016, as well as global right ventricular longitudinal SR -1.56/sec ± 0.57 vs. -1.28/sec ± 0.31, P = 0.02646. At the mean time left ventricular end diastolic volume and left ventricular cardiac output measured by two-dimensional echocardiography both increased significantly P = 0.002145 and 0.013409. Global circumferential strain at mitral level augmented significantly -20.3%± 4.64 vs. -25.39%± 5.22, P = 0.00003. Longitudinal strain of the right ventricle works as indicator of right ventricular function dependent on loading conditions while SR seems to be less dependent on it. Circumferential strain could be used as an indicator of left ventricular response to normalized loading conditions.

Surgical mitral valve replacement with the Melody valve in infants and children: the Italian experience.

AIMS: Paediatric patients with mitral valve (MV) disease have limited options for prosthetic MV replacement. Based on long experience with the stented bovine jugular vein graft (Melody valve) in the right ventricular outflow tract, we aimed to test the use of the Melody valve as a surgical implant in the mitral position in a small group of infants with congenital mitral disease. METHODS AND RESULTS: Eight patients, aged from 3 months to 6.2 years, with congenital MV dysplasia underwent Melody valve implantation in the mitral position between March 2014 and October 2015. Once sutured to the MV annulus, the Melody valve was expanded through a balloon catheter to achieve the best diameter (12-20 mm). Two patients needed ECMO assistance after traditional MV repair and a Melody valve was successfully implanted as possible bail-out. However, neither of them recovered from multi-organ failure and both died, in spite of the well-functioning Melody prosthesis. During follow-up, only one patient underwent catheter-based balloon expansion of the valve. CONCLUSIONS: The medium-term results of this procedure are encouraging. The Melody valve opens up the opportunity to carry out MV replacement in more children at an earlier time point, and it has potential to revolutionise the treatment of MV disease.

Partial abnormal drainage of superior and inferior caval veins into the left atrium: two case reports.

Abnormal connection of the right superior caval vein to the left atrium is an uncommon systemic vein drainage anomaly, with only a few cases reported among congenital heart disease (CHD), around 20 cases published in the medical literature. The inferior vena cava connection with the left atrium, also very rare, can appear directly or in heterotaxy. Clinical suspicion arises due to the presence of cyanosis in the absence of other specific clinical signs (without other associated CHD). We present the cases of two children with abnormal superior and inferior systemic venous return. The first case is an abnormal connection of right superior vena cava to the left atrium associated with persistent left superior vena cava draining into the right atrium through the coronary sinus. The second case is an interruption of the inferior vena cava with hemiazygos continuation, drained into the left superior vena cava, which drained into the left atrium. The diagnosis was imagistic - echocardiography and angiography. Surgical treatment solutions vary from one case to another, usually following anatomic correction. Hypoxia accompanied by cyanosis must bring into question the pathology of systemic venous drainage anomaly, after other common causes have been excluded. Surgery is indicated in all cases due to the risk associated with the presence of right-to-left shunt.

A case report of aorto-pulmonary window in an infant born to a diabetic mother.

Several studies have described the association between pre-gestational maternal diabetes and cardiac disease in the newborn. Infants of diabetic mothers have an increased incidence of congenital heart disease, reported between 3% and 6% compared to 0.8% of the general population. A particularly high prevalence of conotruncal defects has been recently described among congenital heart diseases. This group of malformations affects ventricular outflows, aorta, and pulmonary artery and shares a common embryogenic origin. They include persistence of the truncus arteriosus, transposition of great arteries, tetralogy of Fallot, interruption of the aortic arch, and double outlet right ventricle. Aorto-pulmonary window, a rare congenital heart disease belonging to conotruncal malformations, has never been previously described in association with maternal diabetes. We describe the case of a male infant born to a mother suffering from a poorly controlled type 1 diabetes during pregnancy. In the early postnatal life the infant showed respiratory distress, tachycardia, and failure to thrive. He was found to be affected by aorto-pulmonary window that required corrective surgical intervention. .

Echocardiographic assessment after surgical repair of tetralogy of fallot.

Surgical correction of tetralogy of Fallot is still one of the most frequently performed intervention in pediatric cardiac surgery, and in many cases, it is far from being a complete and definitive correction. It is rather an excellent palliation that solves the problem of cyanosis, but predisposes the patients to medical and surgical complications during follow-up. The decision-making process regarding the treatment of late sequel is among the most discussed topics in adult congenital cardiology. In post-operative Fallot patients, echocardiography is used as the first method of diagnostic imaging and currently allows both a qualitative observation of the anatomical alterations and a detailed quantification of right ventricular volumes and function, of the right ventricular outflow tract, and of the pulmonary valve and pulmonary arteries. The literature introduced many quantitative echocardiographic criteria useful for the understanding of the pathophysiological mechanisms involving the right ventricle and those have made much more objective any decision-making processes.

Role of imaging in interventions on structural heart disease.

Recent technological progresses have led to the development of new devices and procedures which have greatly improved the chance to effectively treat structural heart diseases in both children and adults. Interventional cardiology has been receiving fast and wide implementation as an effective alternative treatment to surgery for several congenital and acquired diseases. The advent of transcatheter valve implantation/repair techniques constitutes one of the main breakthroughs of the last decades. Such development and implementation is strictly related to a continuous progress in cardiac imaging as well. Indeed, multimodality cardiac imaging (such as X-ray, echocardiography, MRI, multidetector computed tomography) has become essential in providing accurate patient selection and in monitoring the interventional procedures in order to optimize the success rate and minimize the frequency of complications. The current article aims at reviewing the role of multimodality imaging for planning and guiding interventions in several structural heart diseases.

Covered-stent implantation to treat aortic coarctation.

Aortic coarctation comprises approximately 7% of all known congenital heart defects. Surgery and balloon angioplasty have been performed for many years but are associated with a significant incidence of recoarctation and aneurysm formation. Although bare-stent implantation decreases the incidence of recoarctation, the risk of aortic dissection or aneurysm formation is not eliminated. Described initially to treat patients with coexistent aneurysm of the aortic wall, we currently believe that covered-stent implantation for aortic coarctation should play a more important role. Our increasing experience from expanding their indication to deal with complications from previous interventions, associated defects or particular anatomical situations has led us to conclude that most of cases of aortic coarctation in adolescents and adults should be treated by the implantation of covered stents.

Layer-oriented simulation tool.

The Layer-Oriented Simulation Tool (LOST) is a numerical simulation code developed for analysis of the performance of multiconjugate adaptive optics modules following a layer-oriented approach. The LOST code computes the atmospheric layers in terms of phase screens and then propagates the phase delays introduced in the natural guide stars' wave fronts by using geometrical optics approximations. These wave fronts are combined in an optical or numerical way, including the effects of wave-front sensors on measurements in terms of phase noise. The LOST code is described, and two applications to layer-oriented modules are briefly presented. We have focus on the Multiconjugate adaptive optics demonstrator to be mounted upon the Very Large Telescope and on the Near-IR-Visible Adaptive Interferometer for Astronomy (NIRVANA) interferometric system to be installed on the combined focus of the Large Binocular Telescope.