Direct visualisation of collateral ventilation in COPD with hyperpolarised gas MRI

Abstract Background Collateral ventilation has been proposed as a mechanism of compensation of respiratory function in obstructive lung diseases but observations of it in vivo are limited. The assessment of collateral ventilation with an imaging technique might help to gain insight into lung physiology and assist the planning of new bronchoscopic techniques for treating emphysema. Objective To obtain images of delayed ventilation that might be related to collateral ventilation over the period of a single breath-hold in patients with chronic obstructive pulmonary disease (COPD). Methods Time-resolved breath-hold hyperpolarised 3He MRI was used to obtain images of the progressive influx of polarised gas into initially non-ventilated defects. Results A time-series of images showed that 3He moves into lung regions which were initially non-ventilated. Ventilation defects with delayed filling were observed in 8 of the 10 patients scanned. Conclusions A method for direct imaging of delayed ventilation within a single breath-hold has been demonstrated in patients with COPD. Images of what is believed to be collateral ventilation and slow filling of peripheral airspaces due to increased flow resistance are presented. The technique provides 3D whole-lung coverage with sensitivity to regional information, and is non-invasive and non-ionising

Mild parenchymal lung disease and/or low diffusion capacity impacts survival and treatment response in patients diagnosed with idiopathic pulmonary arterial hypertension

There are limited published data defining survival and treatment response in patients with mild lung disease and/or reduced gas transfer who fulfil diagnostic criteria for idiopathic pulmonary arterial hypertension (IPAH). Patients diagnosed with IPAH between 2001–19 were identified in the ASPIRE registry. Using pre-specified criteria based on CT imaging and spirometry, patients with a diagnosis of IPAH and no lung disease were termed IPAHno-LD (n=303), and those with minor-mild emphysema or fibrosis were described as IPAHmild-LD (n=190). Survival was significantly better in IPAHno-LD than in IPAHmild-LD (1 and 5-year survival 95% and 70% versus 78% and 22% respectively, p<0.0001). In the combined group of IPAHno-LD and IPAHmild-LD, independent predictors of higher mortality were increasing age, lower DLCO, lower exercise capacity and a diagnosis of IPAHmild-LD (p all <0.05). Exercise capacity and quality of life improved (p both <0.0001) following treatment in patients with IPAHno-LD but not IPAHmild-LD. A proportion of patients with IPAHno-LD had a DLCO <45%; these patients had poorer survival than patients with DLCO ≥45% although demonstrated improved exercise capacity following treatment. The presence of even mild parenchymal lung disease in patients who would be classified as IPAH according to current recommendations has a significant adverse effect on outcomes. This phenotype can be identified using lung function testing and clinical CT reports. Patients with IPAH, no lung disease and severely reduced DLCO may represent a further distinct phenotype. These data suggest that RCTs of targeted therapies in patients with these phenotypes are required

Partial anomalous pulmonary venous drainage in patients presenting with suspected pulmonary hypertension: A series of 90 patients from the ASPIRE registry

Background and objective There are limited data regarding patients with PAPVD with suspected and diagnosed PH. Methods Patients with PAPVD presenting to a large PH referral centre during 2007–2017 were identified from the ASPIRE registry. Results Ninety patients with PAPVD were identified; this was newly diagnosed at our unit in 71 patients (78%), despite 69% of these having previously undergone CT. Sixty‐seven percent had a single right superior and 23% a single left superior anomalous vein. Patients with an SV‐ASD had a significantly larger RV area, pulmonary artery and L‐R shunt and a higher % predicted DLCO (all P  3 WU. Seven of these patients had isolated PAPVD, five of whom (8% of those patients with PH) had anomalous drainage of a single pulmonary vein. Conclusion Undiagnosed PAPVD with or without ASD may be present in patients with suspected PH; cross‐sectional imaging should therefore be specifically assessed whenever this diagnosis is considered. Radiological and physiological markers of L‐R shunt are higher in patients with an associated SV‐ASD. Although many patients with PAPVD and PH may have other potential causes of PH, a proportion of patients diagnosed with PAH have isolated PAPVD in the absence of other causative conditions

Identification of cardiac MRI thresholds for risk stratification in pulmonary arterial hypertension

Rationale: Pulmonary arterial hypertension (PAH) is a life-shortening condition. The European Society of Cardiology and European Respiratory Society and the REVEAL (North American Registry to Evaluate Early and Long-Term PAH Disease Management) risk score calculator (REVEAL 2.0) identify thresholds to predict 1-year mortality. Objectives: This study evaluates whether cardiac magnetic resonance imaging (MRI) thresholds can be identified and used to aid risk stratification and facilitate decision-making. Methods: Consecutive patients with PAH (n = 438) undergoing cardiac MRI were identified from the ASPIRE (Assessing the Spectrum of Pulmonary Hypertension Identified at a Referral Center) MRI database. Thresholds were identified from a discovery cohort and evaluated in a test cohort. Measurements and Main Results: A percentage-predicted right ventricular end-systolic volume index threshold of 227% or a left ventricular end-diastolic volume index of 58 ml/m2 identified patients at low (10%) risk of 1-year mortality. These metrics respectively identified 63% and 34% of patients as low risk. Right ventricular ejection fraction >54%, 37–54%, and <37% identified 21%, 43%, and 36% of patients at low, intermediate, and high risk, respectively, of 1-year mortality. At follow-up cardiac MRI, patients who improved to or were maintained in a low-risk group had a 1-year mortality <5%. Percentage-predicted right ventricular end-systolic volume index independently predicted outcome and, when used in conjunction with the REVEAL 2.0 risk score calculator or a modified French Pulmonary Hypertension Registry approach, improved risk stratification for 1-year mortality. Conclusions: Cardiac MRI can be used to risk stratify patients with PAH using a threshold approach. Percentage-predicted right ventricular end-systolic volume index can identify a high percentage of patients at low-risk of 1-year mortality and, when used in conjunction with current risk stratification approaches, can improve risk stratification. This study supports further evaluation of cardiac MRI in risk stratification in PAH

Incremental Shuttle Walking Test Distance and Autonomic Dysfunction Predict Survival in Pulmonary Arterial Hypertension

Background To ensure effective monitoring of pulmonary arterial hypertension (PAH), a simple, reliable assessment of exercise capacity applicable over a range of disease severity is needed. The aim of this study was to assess the ability of the incremental shuttle walk test (ISWT) to correlate with disease severity, measure sensitivity to change, and predict survival in PAH. Methods We enrolled 418 treatment-naïve patients with PAH with baseline ISWT within 3 months of cardiac catheterization. Clinical validity and prognostic value of ISWT distance were assessed at baseline and 1 year. Results ISWT distance was found to correlate at baseline with World Health Organization functional class, Borg score, and hemodynamics without a ceiling effect (all p 18 beats/min, highest SBP, change in SBP, and 3-minute SBP ratio) were significant predictors of survival (all p < 0.05). Conclusions In patients with PAH, the ISWT is simple to perform, allows assessment of maximal exercise capacity, is sensitive to treatment effect, predicts outcome, and has no ceiling effect. Also, measures of autonomic function made post-exercise predict survival in PAH

The use of sewage treatment works as foraging sites by insectivorous bats

Sewage treatment works with percolating filter beds are known to provide profitable foraging areas for insectivorous birds due to their association with high macroinvertebrate densities. Fly larvae developing on filter beds at sewage treatment works may similarly provide a valuable resource for foraging bats. Over the last two decades, however, there has been a decline in filter beds towards a system of “activated sludge”. Insects and bat activity were surveyed at 30 sites in Scotland employing these two different types of sewage treatment in order to assess the possible implications of these changes for foraging bats. Bat activity (number of passes) recorded from broad-band bat detectors was quantified at three points within each site. The biomass of aerial insects, sampled over the same period as the detector surveys, was measured using a suction trap. The biomass of insects and activity of Pipistrellus spp. was significantly higher at filter beds than at activated sludge sites. In addition, whilst foraging activity of Pipistrellus spp. at filter beds was comparable to that of adjacent “good” foraging habitat, foraging at activated sludge sites was considerably lower. This study indicates the high potential value of an anthropogenic process to foraging bats, particularly in a landscape where their insect prey has undergone a marked decline, and suggests that the current preference for activated sludge systems is likely to reduce the value of treatment works as foraging sites for bats

Maximal exercise testing using the incremental shuttle walking test can be used to risk stratify patients with pulmonary arterial hypertension

Rationale: Exercise capacity predicts mortality in pulmonary arterial hypertension but limited data exist on the routine use of maximal exercise testing. Objectives: This study evaluates a simple to perform maximal test, the incremental shuttle walking test, and its utility in risk stratification in pulmonary arterial hypertension (PAH). Methods: Consecutive patients with pulmonary hypertension were identified from the ASPIRE registry (2001-2018). Thresholds for levels of risk were identified at baseline, tested at follow-up and incorporation into current risk stratification approaches assessed. Results: Of 4524 treatment-naïve patients with pulmonary hypertension who underwent maximal exercise testing 1,847 patients had PAH. A step-wise reduction in one-year-mortality was seen between levels 1 (≤30m; 32% mortality) and 7 (340-420m; 1% mortality) with no mortality for levels 8-12 (≥430m) in idiopathic and connective tissue disease related PAH. Thresholds derived at baseline of ≤180m (>10%; high-risk), 190-330m (5-10%; intermediate-risk) and ≥340m (<5%; low-risk of one-year mortality) were applied at follow-up and also accurately identified levels of risk. Thresholds were incorporated into the REVEAL 2.0 risk score calculator and French low-risk approach to risk stratification and distinct categories of risk remained. Conclusion: We have demonstrated that maximal exercise testing in PAH stratifies mortality-risk at baseline and follow-up. This study highlights the potential value of the incremental shuttle walking test as an alternative to the 6-minute-walk-test, combining some of the advantages of maximal exercise testing whilst maintaining the simplicity of a simple to perform field test

Measurement of the cross section for isolated-photon plus jet production in pp collisions at √s=13 TeV using the ATLAS detector

The dynamics of isolated-photon production in association with a jet in proton–proton collisions at a centre-of-mass energy of 13 TeV are studied with the ATLAS detector at the LHC using a dataset with an integrated luminosity of 3.2 fb−1. Photons are required to have transverse energies above 125 GeV. Jets are identified using the anti- algorithm with radius parameter and required to have transverse momenta above 100 GeV. Measurements of isolated-photon plus jet cross sections are presented as functions of the leading-photon transverse energy, the leading-jet transverse momentum, the azimuthal angular separation between the photon and the jet, the photon–jet invariant mass and the scattering angle in the photon–jet centre-of-mass system. Tree-level plus parton-shower predictions from Sherpa and Pythia as well as next-to-leading-order QCD predictions from Jetphox and Sherpa are compared to the measurements