Real-Life Response to Biologics in Severe Asthma with Nasal Polyposis: Insights from the Belgian Severe Asthma Registry.

BACKGROUND: Nasal polyposis (NP) is a comorbidity of type 2 severe asthma (SA) which could influence response to SA biologics. METHODS: We evaluated (super-) response in SA patients with (NP +) and without NP (NP-) enrolled in the Belgian Severe Asthma Registry (BSAR). RESULTS: 914 patients, of whom 31% NP + , were included. At enrollment, NP + patients had higher annual exacerbation rates, higher number of emergency room visits and more elevated type 2 biomarkers. In the longitudinal subanalysis of 104 patients, both groups had significant and similar asthma responses to asthma biologics, except for a greater increase in FEV1 in the NP + group. Super-response was achieved in 33 patients (32%), irrespective of NP status or type of biologic. CONCLUSION: In conclusion, both NP + and NP - patients had positive treatment responses, with some able to achieve super-response. In SA patients with NP, a greater FEV1 improvement as compared to SA patients without NP was observed.

STRUCTURE-FUNCTION IN SMOKERS : WHEN A SMALL AIRWAYS TEST REALLY REFLECTS THE SMALL AIRWAYS.

INTRODUCTION: If Multiple Breath Washout (MBW) derived acinar ventilation heterogeneity (Sacin) really represents peripheral units, the N2 phase-III of the first MBW exhalation should be curvilinear. This is due to the superposed effect of gas diffusion and convection resulting in an equilibration of N2 concentrations between neighbouring lung units throughout exhalation. We investigated this in smokers with CT-proven functional small airway disease. METHODS: Instantaneous N2slopes were computed over 40ms intervals throughout phase-III and normalized by mean phase-III N2 concentration. N2phase-III (concave) curvilinearity was quantified as the rate at which the instantaneous N2 slope decreases past the phase-II peak over a 1s interval; for a linear N2phase-III unaffected by diffusion, this rate would amount to 0L-1/s. N2phase-III curvilinearity was obtained on the experimental curves and on existing model simulations of N2curves from a normal peripheral lung model and one with missing terminal bronchioles (either 50% or 30% TB left). RESULTS: In forty-six smokers (66 (+8) years; 49 (+26) packyears) with CT-evidence of peripheral lung destruction, instantaneous N2 slope decrease was compared between those with (fSAD+fEmphys)>20% (-0.26+0.14(SD) L-1/s;n=24) and those with (fSAD+fEmphys)<20% (-0.16+0.12(SD)L-1/s;n=22) (P=0.014). Experimental values fell in the range predicted by a realistic peripheral lung model with progressive reduction of terminal bronchioles: values of instantaneous N2-slope decrease obtained from model simulations were -0.09L-1/s (normal lung;100%TB left), -0.17L-1/s (normal lung 50%TB left) and -0.29L-1/s (30%TB left). DISCUSSION : In smokers with CT-based evidence of functional small airways alterations, it is possible to demonstrate that Sacin really does represent the most peripheral airspaces.

Using the phase III slope of exhaled methane during a single breath DLCO test to assess ventilation heterogeneity.

BACKGROUND: The Phase III slope from a single breath nitrogen washout test provides information about ventilation heterogeneity (VH) in the lungs. PURPOSE: To determine if the Phase III slope from the exhaled tracer gas concentration during a standard, single breath DLCO test using rapid gas analysis provides similar information about VH. BASIC PROCEDURES: Retrospective analysis of clinical pulmonary function laboratory data including spirometry, lung volumes, and DLCO. The normalized Phase III slope from the exhaled CH4 concentration (SnCH4) was compared among different patterns of physiologic abnormality and with VA/TLC as an indicator of VH. MAIN FINDINGS: SnCH4 was the steepest in the group with "Obstruction and Low DLCO", with significant differences between this group and the "Normal", "Obstruction with Normal DLCO", "Mixed Obstruction and Restriction" and "Isolated Low DLCO" groups. SnCH4 was steeper in current and former smokers compared to non-smokers. Among the entire study sample, SnCH4 correlated with VA/TLC (Spearman rho = -0.56, p < 0.01) and remained a significant determinant of VA/TLC by regression modeling. PRINCIPAL CONCLUSIONS: The SnCH4 derived from a standard, single breath DLCO test using rapid gas analysis varied among distinct patterns of physiologic abnormalities and was associated with VA/TLC as a measure of VH.

The DS-14 questionnaire: psychometric characteristics and utility in patients with obstructive sleep apnea.

Little is known about type D personality in patients with obstructive sleep apnea (OSA). The DS-14 questionnaire is the standard tool to assess this personality type, but it has not been properly validated in patients with OSA, nor has it been correlated with clinical features in these patients. PURPOSE: To determine the internal consistency and test-retest reliability of the DS-14 questionnaire, as well as the prevalence of type D personality in the overall OSA sample and subgroups. We assessed the influence of type D on perceived symptoms and its congruence with self-reported measures of personality, depression, fatigue, anxiety, quality of life, and quality of sleep. METHODS: Patients with OSA completed the DS-14 questionnaire, Big Five Inventory-2 questionnaire, Hospital Anxiety and Depression Scale, SF-36 Health Survey Questionnaire, Epworth Sleepiness Scale and Stanford Sleepiness Scale, Pittsburgh Sleep Quality Index and Insomnia Severity Index, Fatigue Assessment Scale, and Checklist Individual Strength. After 1 month, the DS-14 questionnaire was repeated. RESULTS: The overall prevalence of type D personality was 32%. Internal consistency (negative affectivity: α = 0.880, social inhibition: α = 0.851) and diagnostic test-retest reliability (kappa value = 0.664) of the DS-14 questionnaire were high. Significantly more symptoms of anxiety, depression, poor sleep quality, fatigue, and a worse health perception were found in OSA with type D. Neither OSA severity nor REM predominance altered these observations. CONCLUSION: The DS-14 questionnaire showed excellent psychometric properties in patients with OSA. The prevalence of type D personality in patients with OSA was higher than in the general population. The presence of type D personality was associated with higher symptom burden.

Real-world data on the efficacy and safety of tezacaftor-ivacaftor in adults living with cystic fibrosis homozygous for F508del and heterozygous for F508del and a residual function mutation.

BACKGROUND: To examine safety and efficacy of tezacaftor-ivacaftor (TEZ/IVA) in a real-life setting in adults living with cystic fibrosis. METHODS: A multicentre retrospective observational study, including adults living with cystic fibrosis (pwCF) eligible for TEZ/IVA, with assessments at baseline, 3 months (visit3mo) and 6 months (visit6mo) after start of treatment. Outcomes included change in FEV1, LCI, FeNO, CFQ-R, estimated number of annual acute exacerbations, BMI, dosage of pancreatic enzyme replacement therapy (PERT) and airway microbiology. We also assessed safety. RESULTS: Forty-eight adult pwCF (mean (±SD) age 33 (±12) years; mean FEV1 65 (±19) %P) were included. Three subgroups were identified: pwCF F/F CFTR modulator-naive (n = 28; 58%), pwCF F/F previously treated with lumacaftor-ivacaftor (n = 11; 23%) and pwCF F/RF (n = 9; 19%). Adverse events were described in 3 pwCF (6%) during the 6-month observation period (in one leading to treatment interruption). At visit3mo, FEV1 had improved in all subgroups. In the entire group, mean FEV1 had increased from 66 (±2.9) %P to 72 (±2.9) %P (p < 0.0001). Similarly, LCI improved by approximately one unit at visit3mo (p = 0.02). At visit6mo mean annual acute exacerbation rate decreased significantly (p = 0.02). Only in the CFQ-R social functioning domain score, a significant improvement was observed at visit6mo (p < 0.01). CONCLUSIONS: We showed that TEZ/IVA is safe, well tolerated and effective in terms of improvement of lung function, ventilation inhomogeneity, health-related social functioning, and reduction of estimated annual acute exacerbation rate, in adult pwCF F/F and F/RF. Results in this real-life study reflect those observed in RCTs.

Getting the Most out of Spirometry: A Tool to Guide Dry Powder Inhaler Use.

BACKGROUND: Dry powder inhaler (DPI) use requires sufficient peak inspiratory flow over the DPI internal resistance (PIFR). OBJECTIVES: We examined whether spirometric peak inspiratory flow (PIFspiro) could serve to predict PIFR in patients with obstructive lung disease. METHOD: Thirty healthy nonsmokers and 140 stable outpatients (70 COPD, 70 asthma) performed spirometry according to the 2019 ERS/ATS spirometry update, yielding PIFspiro. Using a PIFR measurement device with varying orifices, all subjects' PIFR values were recorded for 5 predefined resistance levels, characterized by 5 orifice cross sections (SR). A test group including all healthy subjects, 30 of the asthma, and 30 of the COPD patients was used to establish the relationship between PIFR and both PIFspiro and SR by multiple regression. A validation group including the remaining 40 asthma and 40 COPD patients, served to verify whether their predicted PIFR value corresponded to the measured PIFR for each resistance level. RESULTS: The asthma (FEV1 = 78 ± 17 [SD] %pred) and COPD (FEV1 = 46 ± 17 [SD] %pred) patients under study had varying airway obstruction. In the test group, PIFR could be predicted by ln[PIFspiro] (p < 0.0001), SR (p < 0.0001), and SR2 (p = 0.006), with an adjusted R2 = 0.71. In the validation group, estimated PIFR did not significantly differ from measured PIFR (p > 0.05 for the 5 resistance levels). CONCLUSIONS: We propose a simple method to predict PIFR for a range of common DPI resistances, based on the device characteristics and on the patient's characteristics reflected in PIFspiro. As such, routine spirometry can serve to estimate a patient's specific PIFR without the need for additional testing.

Nitrogen-based lung clearance index: a valid physiological biomarker for the clinic.

Multiple breath washout (MBW) testing is increasingly used as a physiological measurement in the clinic, due in part to the availability of commercial equipment and reference values for MBW indices. Commercial N2 washout devices are usually based on indirect measurement of N2 concentration (CN2), by directly measuring either molar mass and O2 and CO2, or molar mass and CO2. We aim to elucidate the role of two potential pitfalls associated with N2-MBW testing that could override its physiological content: indirect N2 measurement and blood-solubility of N2. We performed MBW in 12 healthy adult subjects using a commercial device (MBWindirect) with simultaneous direct gas concentration measurements by mass spectrometry (MBWdirect) and compared CN2 between MBWdirect and MBWindirect. We also measured argon concentration during the same washouts to verify the maximal effect gas solubility can have on N2-based functional residual capacity (FRC) and lung clearance index (LCI). Continuous N2 concentration traces were very similar for MBWindirect and MBWdirect, resulting in comparable breath-by-breath washout plots of expired concentration and in no significant differences in FRCN2, LCIN2, Scond, and Sacin between the two methods. Argon washouts were slightly slower than N2 washouts, as expected for a less diffusive and more soluble gas. Finally, comparison between LCIN2 and LCIAr indicates that the maximum impact from blood-tissue represents less than half a LCI unit in normal subjects. In conclusion, we have demonstrated by direct measurement of N2 and twice as soluble argon, that indirect N2 measurement can be safely used as a meaningful physiological measurement.NEW & NOTEWORTHY The physiological content of N2 multibreath washout testing has been questioned due to N2 indirect measurement accuracy and N2 blood solubility. With direct measurement of N2 and twice as soluble argon, we show that these effects are largely outweighed by ease of use.

Lung Restriction in Patients With Breast Cancer After Hypofractionated and Conventional Radiation Therapy: A 10-Year Follow-up.

PURPOSE: Previous studies in patients with breast cancer have shown acute radiation therapy-induced reductions of pulmonary diffusing capacity, essentially owing to lung volume restriction. We aimed to assess the long-term effect of 2 radiation therapy regimens, which differed in terms of radiation technique and dose fractionation, on lung function. METHODS AND MATERIALS: From a randomized controlled trial comparing conventional 3-dimensional conformal radiation therapy (CR) and hypofractionated tomotherapy (TT), 84 patients with breast cancer (age at inclusion 54 ± 10 [standard deviation] years) could be assessed at baseline, after 3 months, and after 1, 2, 3, and 10 years. Measurements included forced vital capacity, total lung capacity (TLC), and diffusing capacity (TLco). RESULTS: Radiation therapy-induced lung function changes over 10 years (Δ) were similar for both treatment arms, and in a patient subgroup with negligible history of respiratory disease or smoking (n = 57) these averaged: Δ forced vital capacity = -13 (± 9) percent predicted; ΔTLco = -14 (± 12) percent predicted; and ΔTLC = -11 (± 9) percent predicted. The only significant correlation was between V20 (lung volume exposed to dose exceeding 20 Gy) and ΔTLco (rho = -0.36; P = .007). In this subgroup, as well as in the entire patient cohort, the incurred pulmonary restriction in terms of TLC and TLco showed a greater decline at 3 months for CR versus TT. However, at 10 years, no significant difference could be detected between CR and TT (P = .9 for TLC and P = .2 for TLco in the entire patient cohort). Of the patients with normal TLC and TLco at baseline (ie, above lower limits of normal), respectively 94% and 96% were still normal 10 years later. CONCLUSIONS: In women with breast cancer, conventional 3-dimensional conformal radiation therapy and hypofractionated tomotherapy induce similar restrictive lung patterns during the course of a 10-year period, despite some treatment-dependent differences in the first 3 months. The large majority of women with normal lung function at baseline maintained a normal lung function status 10 years after radiation therapy, irrespective of treatment arm.

In asthma positive phase III slopes can result from structural heterogeneity of the bronchial tree.

We have previously identified bronchial generations 5-7 as the locus of maximum contribution to the convective portion of the phase III slope in computed tomography (CT)-based lung models of patients with asthma. In the present study, we examined how phase III slope is generated locally, by specifically interrogating at individual branch points, the necessary condition for a phase III slope to occur: some degree of convective flow sequencing between any two daughter branches that have a heterogeneity in gas washout concentration between them. Flow sequencing at individual branch points showed a wide range of values, including branch points where flow sequencing was such that phase III slopes were negative locally. Yet, the net effect in the 24 bronchial trees that we studied was that flow sequencing between pairs of less and better ventilated units most frequently drove positive phase III slopes in generations 5-7. By investigating the link of local flow sequencing between any two daughter branches to the corresponding heterogeneity of mechanical lung properties, heterogeneity of compliance was seen to be a major determinant of flow sequencing. In these bronchial structures, compliance heterogeneity was essentially brought about by volume asymmetry resulting from terminating pathways within the three-dimensional (3-D) confines of the lung contours. We conclude that the serial and parallel combination of lung mechanical properties at individual branch points in an asymmetrical branching network generates flow sequencing in mid-range conductive airways, leading to a positive at-mouth phase III slope.NEW & NOTEWORTHY Conceptually, the simplest way to obtain a sloping phase III during a washout exhalation is when there is convective flow sequencing between two lung units, such that the better ventilated unit contributes relatively more to exhaled flow at the beginning of phase III in the exhalation. Here, we show how compliance heterogeneity across the serial and parallel arrangement of branch points in bronchial trees of patients with asthma leads to flow sequencing, and thus phase III slopes of positive sign at the patient's mouth.

Not a wild goose chase: long-lasting MRSA negative status following eradication therapy for chronic MRSA infection in patients with cystic fibrosis.

OBJECTIVES: Prevalence of MRSA in patients with CF has risen over the past decades, and chronic infection with MRSA is associated with worse outcome in this patient group. METHODS: This retrospective observational study investigated long-term eradication rate in pediatric and adult CF patients with chronic MRSA infection, using a 6-month eradication regimen containing 2 oral antibiotics, combined with topical decolonisation measures. Respiratory tract cultures were performed at least every three months, from the first MRSA-positive culture onwards. RESULTS: A total of 24 patients with chronic MRSA infection were identified from our CF patient registry, of which 13 patients underwent an eradication attempt. The regimen consisted of 2 oral antibiotics: a combination of rifampicin, fusidic acid, clindamycin and co-trimoxazol, based on the sensitivity pattern of the MRSA strain. At the end of the study period (median 8.2 years), 12 out of 13 patients (92%) were MRSA negative. None of the patients interrupted treatment due to side-effects. CONCLUSIONS: Eradication of chronic MRSA infection is feasible, well-tolerated and highly successful, and can offer a long-lasting MRSA-negative status, obviating the need for patient segregation.

Peripheral lung effect of elexacaftor/tezacaftor/ivacaftor in adult cystic fibrosis.

Despite being an important patient group, adult cystic fibrosis patients with an FEV1 below 40%predicted have been excluded from clinical trials with elexacaftor/tezacaftor/ivacaftor. We conducted a real-life 3 months follow-up study in 14 adult CF patients (median FEV1 34%predicted) demonstrating significant treatment effects in terms of FEV1 (an increase of 12%predicted at 4 weeks, remaining stable thereafter). Corresponding decreases in lung clearance index LCI (by 31%predicted, down from baseline 247%predicted) and ventilation heterogeneity in the acinar compartment (Sacin) (by 411%predicted, down from baseline 798%predicted) suggest a distinct peripheral lung effect. One patient had intermittent treatment interruptions because of drug-induced liver injury. Our real-life data confirm that treatment with elexacaftor/tezacaftor/ivacaftor is effective in severely obstructive patients, and this is the first study to show time evolution of ventilation distribution improvement, pointing to the peripheral lung as the main site of treatment effect.

Fractal analysis reveals functional unit of ventilation in the lung.

Ventilation is inhomogeneous in the lungs across species. It has been hypothesized that ventilation inhomogeneity is largely determined by the design of the airway branching network. Because exchange of gases at the alveolar barrier is more efficient when gas concentrations are evenly distributed at subacinar length scales, it is assumed that a 'functional unit' of ventilation exists within the lung periphery, where gas concentration becomes uniform. On the other hand, because the morphology of pulmonary airways and alveoli, and the distribution of inhaled fluorescent particles show self-similar fractal properties over a wide range of length scales, it has been predicted that fractal dimension of ventilation approaches unity within an internally homogeneous functional unit of ventilation. However, the existence of such a functional unit has never been demonstrated experimentally due to lack of in situ gas concentration measurements of sufficient spatial resolution in the periphery of a complex bifurcating network. Here, using energy-subtractive synchrotron radiation tomography, we measured the distribution of an inert gas (Xe) in the in vivo rabbit lung during Xe wash-in breathing manoeuvres. The effects of convective flow rate, diffusion and cardiac motion were also assessed. Fractal analysis of resulting gas concentration and tissue density maps revealed that fractal dimension was always smaller for Xe than for tissue density, and that only for the gas, a length scale existed where fractal dimension approached unity. The length scale where this occurred was seen to correspond to that of a rabbit acinus, the terminal structure comprising only alveolated airways. KEY POINTS: Gas ventilation is inhomogeneous in the lung of many species. However, it is not known down to what length scales this inhomogeneity persists. It is generally assumed that ventilation becomes homogeneous at subacinar length scales, beyond the spatial resolution of commonly available imaging techniques, hence this has not been demonstrated experimentally. Here we measured the distribution of inhaled Xe gas in the rabbit lung using synchrotron radiation energy-subtractive imaging and used fractal analysis to show that ventilation becomes internally uniform within regions about the size of rabbit lung acini.