Including Aortic Valve Morphology in Computational Fluid Dynamics Simulations: Initial Findings and Application to Aortic Coarctation

Computational fluid dynamics (CFD) simulations quantifying thoracic aortic flow patterns have not included disturbances from the aortic valve (AoV). 80% of patients with aortic coarctation (CoA) have a bicuspid aortic valve (BAV) which may cause adverse flow patterns contributing to morbidity. Our objectives were to develop a method to account for the AoV in CFD simulations, and quantify its impact on local hemodynamics. The method developed facilitates segmentation of the AoV, spatiotemporal interpolation of segments, and anatomic positioning of segments at the CFD model inlet. The AoV was included in CFD model examples of a normal (tricuspid AoV) and a post-surgical CoA patient (BAV). Velocity, turbulent kinetic energy (TKE), time-averaged wall shear stress (TAWSS), and oscillatory shear index (OSI) results were compared to equivalent simulations using a plug inlet profile. The plug inlet greatly underestimated TKE for both examples. TAWSS differences extended throughout the thoracic aorta for the CoA BAV, but were limited to the arch for the normal example. OSI differences existed mainly in the ascending aorta for both cases. The impact of AoV can now be included with CFD simulations to identify regions of deleterious hemodynamics thereby advancing simulations of the thoracic aorta one step closer to reality

Aortic valve replacement in neonates and infants: An analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database

ObjectiveWe sought to describe early outcomes of aortic valve replacement in neonates and infants across a large multicenter cohort.MethodsNeonates and infants in the Society of Thoracic Surgeons Congenital Heart Surgery Database undergoing nontruncal aortic valve replacement with the Ross-Konno procedure, Ross procedure, or homograft replacement from 2000 to 2009 were included. Preoperative characteristics, operative data, and early outcomes are described.ResultsA total of 160 patients (43 neonates, 117 infants) from 47 centers were included. Society of Thoracic Surgeons–defined preoperative risk factors were present in 76 patients (48%) and were most prevalent in neonates (67%) and patients undergoing homograft aortic valve replacement (93%). Concomitant arch repair or mitral valve surgery was performed in 30 patients (19%) and 19 patients (12%), respectively. Postoperative mechanical circulatory support was used in 17 patients (11%). Overall in-hospital mortality was 18% and was highest for neonates (28%) and patients undergoing homograft aortic valve replacement (40%). Concomitant arch repair was associated with higher in-hospital mortality (33% vs 15%, P = .02), whereas concurrent mitral valve surgery was not (21% vs 18%, P = .73). Postoperative mechanical circulatory support was also associated with increased in-hospital mortality (65% vs 13%, P < .0001).ConclusionsNeonates and infants undergoing aortic valve replacement are a high-risk group, with hospital mortality comparable with some of the highest risk procedures in this age group. The requirement for arch repair or postoperative mechanical circulatory support was associated with an increased risk of death in this cohort

Human Genotyping and An Experimental Model Reveal NPR-C as A Possible Contributor to Morbidity In Coarctation Of The Aorta

Coarctation of the aorta (CoA) is a common congenital cardiovascular (CV) defect characterized by a stenosis of the descending thoracic aorta. Treatment exists, but many patients develop hypertension (HTN). Identifying the cause of HTN is challenging because of patient variability (e.g., age, follow-up duration, severity) and concurrent CV abnormalities. Our objective was to conduct RNA sequencing of aortic tissue from humans with CoA to identify a candidate gene for mechanistic studies of arterial dysfunction in a rabbit model of CoA devoid of the variability seen with humans. We present the first known evidence of natriuretic peptide receptor C (NPR-C; aka NPR3) downregulation in human aortic sections subjected to high blood pressure (BP) from CoA versus normal BP regions (validated to PCR). These changes in NPR-C, a gene associated with BP and proliferation, were replicated in the rabbit model of CoA. Artery segments from this model were used with human aortic endothelial cells to reveal the functional relevance of altered NPR-C activity. Results showed decreased intracellular calcium ([Ca2+]i) activity to C-type natriuretic peptide (CNP). Normal relaxation induced by CNP and atrial natriuretic peptide was impaired for aortic segments exposed to elevated BP from CoA. Inhibition of NPR-C (M372049) also impaired aortic relaxation and [Ca2+]i activity. Genotyping of NPR-Cvariants predicted to be damaging revealed that rs146301345 was enriched in our CoA patients, but sample size limited association with HTN. These results may ultimately be used to tailor treatment for CoA based on mechanical stimuli, genotyping, and/or changes in arterial function

Measurement of the t(t)over-bar production cross section in pp collisions at root s=7 TeV in dilepton final states containing a tau

The top quark pair production cross section is measured in dilepton events with one electron or muon, and one hadronically decaying tau lepton from the decay t (t) over bar -> (l nu(l))((sic)(h)nu((sic)))b (b) over bar, (l = e, mu). The data sample corresponds to an integrated luminosity of 2.0 fb(-1) for the electron channel and 2.2 fb(-1) for the muon channel, collected by the CMS detector at the LHC. This is the first measurement of the t (t) over bar cross section explicitly including tau leptons in proton- proton collisions at root s = 7 TeV. The measured value sigma(t (t) over bar) = 143 +/- 14(stat) +/- 22(syst) +/- 3(lumi) pb is consistent with the standard model predictions

Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

Peer reviewe

Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| &lt; 0.03 at 95% confidence level. [Figure not available: see fulltext.

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe