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Whitfield CA, Horsley A, Jensen OE, Horn FC, Collier GJ, Smith LJ, Wild JM. Model-based Bayesian inference of the ventilation distribution in patients with cystic fibrosis from multiple breath washout, with comparison to ventilation MRI. Respir Physiol Neurobiol 2022; 302:103919. [PMID: 35562095 DOI: 10.1016/j.resp.2022.103919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 04/06/2022] [Accepted: 05/05/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Indices of ventilation heterogeneity (VH) from multiple breath washout (MBW) have been shown to correlate well with VH indices derived from hyperpolarised gas ventilation MRI. Here we report the prediction of ventilation distributions from MBW data using a mathematical model, and the comparison of these predictions with imaging data. METHODS We developed computer simulations of the ventilation distribution in the lungs to model MBW measurement with 3 parameters: σV, determining the extent of VH; V0, the lung volume; and VD, the dead-space volume. These were inferred for each individual from supine MBW data recorded from 25 patients with cystic fibrosis (CF) using approximate Bayesian computation. The fitted models were used to predict the distribution of gas imaged by 3He ventilation MRI measurements collected from the same visit. RESULTS The MRI indices measured (I1/3, the fraction of pixels below one-third of the mean intensity and ICV, the coefficient of variation of pixel intensity) correlated strongly with those predicted by the MBW model fits (r=0.93,0.88 respectively). There was also good agreement between predicted and measured MRI indices (mean bias ± limits of agreement: I1/3:-0.003±0.118 and ICV:-0.004±0.298). Fitted model parameters were robust to truncation of MBW data. CONCLUSION We have shown that the ventilation distribution in the lung can be inferred from an MBW signal, and verified this using ventilation MRI. The Bayesian method employed extracts this information with fewer breath cycles than required for LCI, reducing acquisition time required, and gives uncertainty bounds, which are important for clinical decision making.
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Affiliation(s)
- Carl A Whitfield
- Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester, UK; Department of Mathematics, University of Manchester, Manchester, UK.
| | - Alexander Horsley
- Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester, UK
| | - Oliver E Jensen
- Department of Mathematics, University of Manchester, Manchester, UK
| | - Felix C Horn
- POLARIS, Imaging Sciences, Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, UK
| | - Guilhem J Collier
- POLARIS, Imaging Sciences, Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, UK
| | - Laurie J Smith
- POLARIS, Imaging Sciences, Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, UK
| | - Jim M Wild
- POLARIS, Imaging Sciences, Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, UK
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Rowe SM, Jones I, Dransfield MT, Haque N, Gleason S, Hayes KA, Kulmatycki K, Yates DP, Danahay H, Gosling M, Rowlands DJ, Grant SS. Efficacy and Safety of the CFTR Potentiator Icenticaftor (QBW251) in COPD: Results from a Phase 2 Randomized Trial. Int J Chron Obstruct Pulmon Dis 2020; 15:2399-2409. [PMID: 33116455 PMCID: PMC7547289 DOI: 10.2147/copd.s257474] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/15/2020] [Indexed: 12/30/2022] Open
Abstract
Rationale Excess mucus plays a key role in COPD pathogenesis. Cigarette smoke-induced cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction may contribute to disease pathogenesis by depleting airway surface liquid and reducing mucociliary transport; these defects can be corrected in vitro by potentiating CFTR. Objective To assess the efficacy of the CFTR potentiator icenticaftor in improving airflow obstruction in COPD patients with symptoms of chronic bronchitis. Methods In this double-blind, placebo-controlled study, COPD patients were randomized (2:1) to either icenticaftor 300 mg or placebo b.i.d. This non-confirmatory proof of concept study was powered for lung clearance index (LCI) and pre-bronchodilator FEV1, with an estimated sample size of 90 patients. The primary endpoint was change from baseline in LCI for icenticaftor versus placebo at Day 29; key secondary endpoints included change from baseline in pre- and post-bronchodilator FEV1 on Day 29. Key exploratory endpoints included change from baseline in sweat chloride, plasma fibrinogen levels, and sputum colonization. Results Ninety-two patients were randomized (icenticaftor, n=64; placebo, n=28). At Day 29, icenticaftor showed no improvement in change in LCI (treatment difference: 0.28 [19% probability of being better than placebo]), an improvement in pre-bronchodilator FEV1 (mean: 50 mL [84% probability]) and an improvement in post-bronchodilator FEV1 (mean: 63 mL [91% probability]) over placebo. Improvements in sweat chloride, fibrinogen and sputum bacterial colonization were also observed. Icenticaftor was safe and well tolerated. Conclusion The CFTR potentiator icenticaftor increased FEV1 versus placebo after 28 days and was associated with improvements in systemic inflammation and sputum bacterial colonization in COPD patients; no improvements in LCI with icenticaftor were observed.
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Affiliation(s)
- Steven M Rowe
- University of Alabama at Birmingham, Department of Medicine, Birmingham, AL, USA
| | - Ieuan Jones
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Mark T Dransfield
- University of Alabama at Birmingham, Department of Medicine, Birmingham, AL, USA
| | - Nazmul Haque
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Stephen Gleason
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Katy A Hayes
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | | | - Denise P Yates
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | | | - Martin Gosling
- Enterprise Therapeutics, Brighton, UK
- Sussex Drug Discovery Centre, University of Sussex, Brighton, UK
| | | | - Sarah S Grant
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
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Shaw M, Oppelaar MC, Jensen R, Stanojevic S, Davis SD, Retsch-Bogart G, Ratjen FA. The utility of moment ratios and abbreviated endpoints of the multiple breath washout test in preschool children with cystic fibrosis. Pediatr Pulmonol 2020; 55:649-653. [PMID: 31899855 DOI: 10.1002/ppul.24618] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/12/2019] [Indexed: 11/08/2022]
Abstract
BACKGROUND The multiple breath washout (MBW) test may be most useful in tracking disease progression over time to inform treatment decisions. In the clinical setting, alternative outcomes, which can be obtained quickly and easily, may facilitate interpretation of clinically relevant changes in lung function. METHODS In this secondary analysis of data from 78 cystic fibrosis (CF) and 72 healthy control (HC) subjects between the ages of 2.6 and 5.9 years, MBW was performed at enrollment, 1, 3, 6, 9, and 12 months, as well as during symptomatic visits using the Exhalyzer D (EcoMedics AG, Duernten, Switzerland). The lung clearance index, LCI2.5, was compared to moment ratios (M1 /M0 and M2 /M0 ) at the standard cutoff (1/40th of starting tracer gas concentration) as well as LCI5 and moment ratios at 1/20th of the starting concentration (M1 /M0 at LCI5 , and M2 /M0 at LCI5 ). RESULTS All outcomes were able to distinguish between health and disease. LCI5 reduced testing time by 40% and increased feasibility by more than 10%. The limits of biological reproducibility in healthy children were similar between LCI2.5 (15%), LCI5 (12%), M1 /M0 at LCI2.5 (14%), and M1 /M0 at LCI5 (12%), but markedly larger for M2 /M0 at LCI2.5 (30%) and M2 /M0 at LCI5 (25%). Each outcome deteriorated significantly with worsening pulmonary symptoms, the magnitude of deterioration was greatest for M2 /M0 . CONCLUSIONS In preschool children with CF, LCI5 was more feasible to obtain and track disease progression. The second moment ratio was most sensitive to pulmonary symptoms, but had the greatest variability both within and between subjects.
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Affiliation(s)
- Michelle Shaw
- Translational Medicine Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Martinus C Oppelaar
- Translational Medicine Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Paediatric Pulmonology, Radboud University Medical Center, Amalia Children's Hospital, Nijmegen, The Netherlands
| | - Renee Jensen
- Translational Medicine Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sanja Stanojevic
- Translational Medicine Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Stephanie D Davis
- Division of Pediatric Pulmonology, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - George Retsch-Bogart
- Division of Pediatric Pulmonology, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Felix A Ratjen
- Division of Respiratory Medicine, Department of Pediatrics, Hospital for Sick Children, Toronto, Ontario, Canada
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Poncin W, Lebecque P. [Lung clearance index in cystic fibrosis]. Rev Mal Respir 2019; 36:377-395. [PMID: 30686561 DOI: 10.1016/j.rmr.2018.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 03/28/2018] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Small airways' involvement in cystic fibrosis (CF) pulmonary disease is a very early event, which can progress sub-clinically and insidiously since it is poorly reflected by commonly used lung function tests. STATE OF ART Sensitive and discriminative tools are available to investigate small airways function. However their complexity and/or invasiveness has confined their use to research purposes and to some specialized research teams. By contrast, the multiple breath washout (MBW) test is more affordable and non-invasive. Lung clearance index (LCI), which is the most used derived parameter, is reproducible and much more sensitive than spirometry in detecting small airways disease. However, MBW is operator dependent. PERSPECTIVES The recent commercialization of devices assessing LCI launches MBW as a potential tool in routine clinical care, although its use currently remains mostly dedicated to research purposes. However, important differences in LCI between various equipment settings raise a number of theoretical questions. Specific algorithms should be refined and more transparent. Standardization of MBW is still an ongoing process. Whether other MBW derived indices can prove superior over LCI deserves further study. CONCLUSIONS In CF, LCI is now a well-established outcome in research settings to detect early lung function abnormalities and new treatment effects, especially in patients with mild lung disease. In these patients, LCI seems an attractive tool for clinicians too. Yet, further investigation is needed to define clinically significant changes in LCI and to which extent this index can be useful in guiding clinical decisions remains to be studied.
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Affiliation(s)
- W Poncin
- Pôle de pneumologie, ORL et dermatologie, université Catholique de Louvain, institut de recherche expérimentale et clinique (IREC), 1200 Bruxelles, Belgique; Service de médecine physique et réadaptation, cliniques universitaires Saint-Luc, 1200 Bruxelles, Belgique.
| | - P Lebecque
- Pneumologie pédiatrique & centre de référence pour la mucoviscidose, cliniques universitaires Saint-Luc, 1200 Bruxelles, Belgique
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Lung Clearance Index and Quantitative Computed Tomography of Post-Infectious Bronchiolitis Obliterans in Infants. Sci Rep 2017; 7:15128. [PMID: 29123150 PMCID: PMC5680196 DOI: 10.1038/s41598-017-15330-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 09/19/2017] [Indexed: 11/12/2022] Open
Abstract
Post-infectious bronchiolitis obliterans (BO) could be diagnosed via spirometry and chest computed tomography (CT); however, these tests are limited in infants. We aimed to evaluate the utility of lung clearance index (LCI) and air-trapping lung volume from chest CT in infants. This prospective study included 20 infants (mean age, 10.9 ± 6.3 months) diagnosed with post-infectious BO between 2009 and 2016. All subjects underwent multiple breath washout tests. For quantitative analysis of chest CT, the mean lung area attenuation value was used as an individual cutoff to determine the air-trapping lung volume. The mean cutoff lung attenuation value was −659 Hounsfield units, the mean total lung volume was 265 ml, and the mean air-trapping lung volume percentage was 22.9%. Functional residual capacity correlated with total lung volume and normal attenuation lung volume (p < 0.02). LCI (p < 0.02) and moment ratio (MR) 1 (p < 0.05) correlated with the air-trapping lung volume percentage. The concordance indices of LCI (0.659, p = 0.025) and MR1 (0.642, p = 0.046) were significantly correlated with the air-trapping lung volume percentage from CT. LCI and quantitative air-trapping lung volume from chest CT are feasible, complimentary tools for assessing infants with post-infectious BO.
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Tonga KO, Robinson PD, Farah CS, King GG, Thamrin C. In vitro and in vivo functional residual capacity comparisons between multiple-breath nitrogen washout devices. ERJ Open Res 2017; 3:00011-2017. [PMID: 29204436 PMCID: PMC5703358 DOI: 10.1183/23120541.00011-2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 06/23/2017] [Indexed: 11/25/2022] Open
Abstract
Functional residual capacity (FRC) accuracy is essential for deriving multiple-breath nitrogen washout (MBNW) indices, and is the basis for device validation. Few studies have compared existing MBNW devices. We evaluated in vitro and in vivo FRC using two commercial MBNW devices, the Exhalyzer D (EM) and the EasyOne Pro LAB (ndd), and an in-house device (Woolcock in-house device, WIMR). FRC measurements were performed using a novel syringe-based lung model and in adults (20 healthy and nine with asthma), followed by plethysmography (FRCpleth). The data were analysed using device-specific software. Following the results seen with ndd, we also compared its standard clinical software (ndd v.2.00) with a recent upgrade (ndd v.2.01). WIMR and EM fulfilled formal in vitro FRC validation recommendations (>95% of FRC within 5% of known volume). Ndd v.2.00 underestimated in vitro FRC by >20%. Reanalysis using ndd v.2.01 reduced this to 11%, with 36% of measurements ≤5%. In vivo differences from FRCpleth (mean±sd) were 4.4±13.1%, 3.3±11.8%, −20.6±11% (p<0.0001) and −10.5±10.9% (p=0.005) using WIMR, EM, ndd v.2.00 and ndd v.2.01, respectively. Direct device comparison highlighted important differences in measurement accuracy. FRC discrepancies between devices were larger in vivo, compared to in vitro results; however, the pattern of difference was similar. These results represent progress in ongoing standardisation efforts. Multiple-breath washout devices are not yet comparablehttp://ow.ly/bB7b30eAs0c
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Affiliation(s)
- Katrina O Tonga
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia.,Dept of Respiratory Medicine, Concord Hospital, Sydney, Australia
| | - Paul D Robinson
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, Australia
| | - Claude S Farah
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Concord Hospital, Sydney, Australia
| | - Greg G King
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia.,Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, Australia
| | - Cindy Thamrin
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia
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