Subject-specific simulation for non-invasive assessment of aortic coarctation: Towards a translational approach

We present a multi-scale CFD-based study conducted in a cohort of 11 patients with coarctation of the aorta (CoA). The study explores the potential for implementation of a workflow using non-invasive routinely collected medical imaging data and clinical measurements to provide a more detailed insight into local aortic haemodynamics in order to support clinical decision making. Our approach is multi-scale, using a reduced-order model (1D/0D) and an optimization process for the personalization of patient-specific boundary conditions and aortic vessel wall parameters from non-invasive measurements, to inform a more complex model (3D/0D) representing 3D aortic patient-specific anatomy. The reliability of the modelling approach is investigated by comparing 3D/0D model pressure drop estimation with measured peak gradients recorded during diagnostic cardiac catheterization and 2D PC-MRI flow rate measurements in the descending aorta. The current study demonstrated that the proposed approach requires low levels of user interaction, making it suitable for the clinical setting. The agreement between computed blood pressure drop and catheter measurements is 10 ± 8 mmHg at the coarctation site. The comparison between CFD derived and catheter measured pressure gradients indicated that the model has to be improved, suggesting the use of time varying pressure waveforms to further optimize the tuning process and modelling assumptions

The impact of trisomy 21 on treatment modalities and outcome in adults with congenital heart disease in Switzerland.

Trisomy 21 (T21) is associated in 40-45% of cases with heart defects, most commonly shunt lesions. These defects, if not repaired, can lead to irreversible shunt-induced pulmonary hypertension (i.e. Eisenmenger syndrome [ES]). In ES patients, intracardiac repair is no longer possible, but selective pulmonary vasodilators may increase exercise capacity and improve prognosis. This study aimed to estimate the prevalence of cardiac defects and ES in adult T21 patients and to assess the impact of T21 on treatment modalities and outcome in ES patients. A questionnaire was sent to 6906 Swiss physicians inviting them to indicate the number of adults with T21 under their care (survey report). We also analyzed all adults with ES (with and without T21) included in the Swiss Adult Congenital HEart disease Registry (SACHER) and studied the impact of T21 on the use of selective pulmonary vasodilators and survival. In the survey, 348 physicians cared for 695 adult T21 patients. Overall, 24% of T21 survey patients were known to have a cardiac defect, one in four with a defect had developed ES and 13% of those with ES were on specific pulmonary vasodilators. In SACHER, ES was present in 2% of adults with congenital heart disease and selective pulmonary vasodilators were used in 68% of ES patients with T21. In SACHER, survival during follow-up was worse with higher nt-proBNP levels (hazard ratio [HR] = 1.15 per 1000 units, 95% confidence interval [CI] = 1.02-1.29) and lower left ventricular ejection fraction (HR = 1.07 per percent decrease, 95% CI = 1.01-1.13). Age at inclusion and T21 did not affect survival. The prevalence of cardiac defects in adults with T21 in Switzerland is half the prevalence in children. T21 is over-represented among adults with ES. Raised awareness of the therapeutic options for T21 patients with ES is warranted

Swiss Adult Congenital HEart disease Registry (SACHER) - rationale, design and first results.

In 2013, a prospective registry for adults with congenital heart disease (CHD) was established in Switzerland, providing detailed data on disease characteristics and outcomes: Swiss Adult Congenital HEart disease Registry (SACHER). Its aim is to improve the knowledge base of outcomes in adults with CHD. The registry design and baseline patient characteristics are reported. All patients with structural congenital heart defects or hereditary aortopathies, followed-up at dedicated adult CHD clinics, are asked to participate in SACHER. Data of participants are pseudonymised and collected in an electronic, web-based, database (secuTrial®). Collected data include detailed diagnosis, type of repair procedures, previous complications and adverse outcomes during follow-up. From May 2014 to December 2016, 2836 patients (54% male, mean age 34 ± 14 years), with a wide variety of congenital heart lesions, have been enrolled into SACHER. Most prevalent were valve lesions (25%), followed by shunt lesions (22%), cyanotic and other complex congenital heart disease (16%), diseases affecting the right heart, i.e., tetralogy of Fallot or Ebstein anomaly (15%), and diseases of the left ventricular outflow tract (13%); 337 patients (12%) had concomitant congenital syndromes. The majority had undergone previous repair procedures (71%), 47% of those had one or more reinterventions. SACHER collects multicentre data on adults with CHD. Its structure enables prospective data analysis to assess detailed, lesion-specific outcomes with the aim to finally improve long-term outcomes

Cardiac Implantable Electronic Device-Related Infection Due to Granulicatella adiacens.

Cardiac implantable electronic device-related infection is clinically challenging. Curative treatment commonly includes system removal. A case caused by Granulicatella adiacens occurred in a 32-year-old woman. Clinical course, literature review, and biofilm investigations enabled successful antibiotic management without system removal

Use of Spatial Information and Search Strategies in a Water Maze Analog in Drosophila melanogaster

Learning the spatial organization of the environment is crucial to fitness in most animal species. Understanding proximate and ultimate factors underpinning spatial memory is thus a major goal in the study of animal behavior. Despite considerable interest in various aspects of its behavior and biology, the model species Drosophila melanogaster lacks a standardized apparatus to investigate spatial learning and memory. We propose here a novel apparatus, the heat maze, conceptually based on the Morris water maze used in rodents. Using the heat maze, we demonstrate that D. melanogaster flies are able to use either proximal or distal visual cues to increase their performance in navigating to a safe zone. We also show that flies are actively using the orientation of distal visual cues when relevant in targeting the safe zone, i.e., Drosophila display spatial learning. Parameter-based classification of search strategies demonstrated the progressive use of spatially precise search strategies during learning. We discuss the opportunity to unravel the mechanistic and evolutionary bases of spatial learning in Drosophila using the heat maze

A role for the cell-wall protein silacidin in cell size of the diatom Thalassiosira pseudonana

Diatoms contribute 20% of global primary production and form the basis of many marine food webs. Although their species diversity correlates with broad diversity in cell size, there is also an intraspecific cell-size plasticity due to sexual reproduction and varying environmental conditions. However, despite the ecological significance of the diatom cell size for food-web structure and global biogeochemical cycles, our knowledge about genes underpinning the size of diatom cells remains elusive. Here, a combination of reverse genetics, experimental evolution and comparative RNA8 sequencing analyses enabled us to identify a previously unknown genetic control of cell size in the diatom Thalassiosira pseudonana. In particular, the targeted deregulation of the expression of the cell-wall protein silacidin caused a significant increase in valve diameter. Remarkably, the natural downregulation of the silacidin gene transcript due to experimental evolution under low temperature also correlated with cell-size increase. Our data give first evidence for a genetically controlled regulation of cell size in Thalassiosira pseudonana and possibly other centric diatoms as they also encode the silacidin gene in their genomes