Impairments and prognostic factors for survival in patients with idiopathic pulmonary fibrosis

Adipokines in interstitial lung diseases

Interstitial lung diseases (ILD) are a heterogenic group of respiratory diseases with complex pathogenesis. A growing number of evidence suggests role of adipose tissue and it's hormones (adipokines) in pathogenesis of various disorders, including lung tissue diseases. The aim of this study was to assess the concentrations of selected adipokines and their receptors (apelin, adiponectin, chemerin, chemerin receptor - CMKLR1) in patients with IPF (idiopathic pulmonary fibrosis) and sarcoidosis in comparison to healthy controls. We found changes in adipokines concentrations in ILD. Adiponectin concentrations were higher in all respiratory diseases patients in comparison to healthy controls. Apelin concentration in ILD patients was higher then those in healthy subjects. The trend of chemerin and CMKLR1 concentrations were similar, with highest concentrations seen in sarcoidosis. The study shows a difference of adipokines concentrations between patients with ILD and healthy controls. Adipokines are a potential marker and therapeutic target in patients with IPF and sarcoidosis.

Impact of physical functional capacity on quality of life in patients with interstitial lung diseases

This study aimed to investigate the physical functioning predictors for health-related quality of life (HRQL) decline in patients with idiopathic interstitial fibrosis (IPF), sarcoidosis and other interstitial lung disease (ILD). The study enrolled 52 patients with ILD and 16 healthy individuals. Participants' HRQL was assessed using the 36-item Short-Form Health Survey questionnaire. Spirometry, physical performance, and daily physical activity (PA) were monitored. Patients with IPF showed significantly lower PA compared to patients with other ILD (p =0.002)and sarcoidosis (p =0.01). The type of disease aetiology had no significant effect on aerobic capacity, HRQL and fatigue. Patients with ILD showed significant greater fatigue, lower physical functioning and greater physical aspects scores compared to the control group (F=6.0; p=0.018; F=12.64; p=0.001, respectively). A significant positive correlation was observed between 6-minute walking distance (6MWD) and the physical domain of HRQL (r=0.35, p=0.012) and PA and the physical aspects of HRQL (r=0.37, p=0.007). This study revealed that the key predictors for HRQL decline were lower lung function, lower PA and physical performance.

Exercise Tolerance in Patients With Idiopathic Pulmonary Fibrosis, Effect of Supplemental Oxygen

Exercise tolerance in patients with idiopathic pulmonary fibrosis IPF is mainly limited by mechanical constrain of ventilation and high physiologic dead space. Oxygen enriched gas inhalation seems to increase ventilatory efficiency by reduction of dead space to tidal volume ratio (VD/VT) which probably mirrors improved pulmonary capillary flow and leads to longer physical tolerance at lower level of minute ventilation. The effect is noticeable at FIO2 that can be delivered in rehabilitation purposes or daily living activities.

Cardiorespiratory responses to muscle metaboreflex activation in fibrosing interstitial lung disease

New Findings

What is the central question of this study?

We determined whether sensory feedback from metabolically sensitive skeletal muscle afferents (metaboreflex) causes a greater ventilatory response and higher dyspnoea ratings in fibrosing interstitial lung disease (FILD).

What is the main finding and its importance?

Ventilatory responses and dyspnoea ratings during handgrip exercise and metaboreflex isolation were not different in FILD and control groups. Blood pressure and heart rate responses to handgrip were attenuated in FILD but not different to controls during metaboreflex isolation. These findings suggest that the muscle metaboreflex contribution to the respiratory response to exercise is not altered in FILD.

Abstract

Exercise limitation and dyspnoea are hallmarks of fibrosing interstitial lung disease (FILD); however, the physiological mechanisms are poorly understood. In other respiratory diseases, there is evidence that an augmented muscle metaboreflex may be implicated. We hypothesized that metaboreflex activation in FILD would result in elevated ventilation and dyspnoea ratings compared to healthy controls, due to augmented muscle metaboreflex. Sixteen FILD patients (three women, 69±14 years; mean±SD) and 16 age‐matched controls (four women, 67±7 years) were recruited. In a randomized cross‐over design, participants completed two min of rhythmic handgrip followed by either (i) two min of post‐exercise circulatory occlusion (PECO trial) to isolate muscle metaboreflex activation, or (ii) rested for four min (Control trial). Minute ventilation (V˙E; pneumotachometer), dyspnoea ratings (0–10 Borg scale), mean arterial pressure (MAP; finger photoplethysmography) and heart rate (HR; electrocardiogram) were measured. V˙E was higher in the FILD group at baseline and exercise increased V˙E similarly in both groups. V˙E remained elevated during PECO, but there was no between‐group difference in the magnitude of this response (ΔV˙E FILD 4.2 ± 2.5 L·min^–1 vs. controls 3.6 ± 2.4 L·min^–1, P = 0.596). At the end of PECO, dyspnoea ratings in FILD were similar to controls (1.0 ± 1.3 units vs. 0.5 ± 1.1 units). Exercise increased MAP and HR (P < 0.05) in both groups; however, responses were lower in FILD. Collectively, these findings suggest that there is not an augmented effect of the muscle metaboreflex on breathing and dyspnoea in FILD, but haemodynamic responses to handgrip are reduced relative to controls.

Cardiopulmonary exercise testing in interstitial lung diseases and the value of ventilatory efficiency

Interstitial lung diseases (ILDs) are diverse parenchymal pulmonary disorders, primarily characterised by alveolar and interstitial inflammation and/or fibrosis, and sharing pathophysiological similarities. Thus, patients generally harbour common respiratory symptoms, lung function abnormalities and modified exercise adaptation. The most usual and disabling complaint is exertional dyspnoea, frequently responsible for premature exercise interruption. Cardiopulmonary exercise testing (CPET) is increasingly used for the clinical assessment of patients with ILD. This is because exercise performance or dyspnoea on exertion cannot reliably be predicted by resting pulmonary function tests. CPET, therefore, provides an accurate evaluation of functional capacity on an individual basis. CPET can unmask anomalies in the integrated functions of the respiratory, cardiovascular, metabolic, peripheral muscle and neurosensory systems in ILDs. CPET uniquely provides an evaluation of all above aspects and can help clinicians shape ILD patient management. Preliminary evidence suggests that CPET may also generate valuable prognostic information in ILDs and can be used to shed light on the presence of associated pulmonary hypertension. This review aims to provide comprehensive and updated evidence concerning the clinical utility of CPET in ILD patients, with particular focus on the physiological and clinical value of ventilatory efficiency (V˙_E/V˙_CO2 ).

Prognostic value of 6-min walk stress echocardiography in patients with interstitial lung disease

BACKGROUND

The 6-min walk test (6MWT) provides prognostic information for patients with interstitial lung disease (ILD). Parameter determined by Doppler echocardiography after the 6MWT (6 MW stress echocardiography) is shown to be a predictor of future development of pulmonary hypertension in patients with connective tissue disease. However, the clinical utility of 6 MW stress echocardiography in predicting cardiopulmonary events in patients with ILD remains unknown. We examined whether parameters determined by 6 MW stress echocardiography independent predictors of adverse events in patients with ILD.

METHODS

Echocardiographic examinations were performed in 68 consecutively enrolled patients with ILD (age, 65 ± 10 years, 65% men). A pressure gradient of tricuspid regurgitation (TRPG) and pulmonary vascular resistance (PVRecho) calculated using the following formula [PVRecho = (peak velocity of TR × 10/time-velocity integral of right ventricular outflow (RVOT-VTI)) + 0.16] were measured at baseline and at post 6MWT. Data for parameters of pulmonary functional tests and for 6MWT were collected.

RESULTS

During a mean follow-up period of 22 ± 12 months, 22 patients experienced cardiopulmonary events. In univariate analysis, %VC, TRPG, PVRecho, TRPG post 6MWT, and PVRecho post 6MWT were significantly associated with cardiopulmonary events. Multivariate analysis using the Cox proportional hazards model indicated that %VC [hazard ratio (HR): 0.97, p = 0.009] and PVRecho post 6MWT (HR: 1.77, p = 0.004) were independent predictors of cardiopulmonary events in patients with ILD.

CONCLUSIONS

In addition to parameters of pulmonary function tests, increased PVRecho post 6MWT is a significant predictor of cardiopulmonary events in patients with ILD. A 6 MW stress echocardiography is useful in assessing the risk of adverse events in patients with ILD.

A role for cardiopulmonary exercise testing in detecting physiological changes underlying health status in Idiopathic pulmonary fibrosis: a feasibility study

Introduction

There is limited data available on the use of CPET as a predictive tool for disease outcomes in the setting of IPF. We investigated the feasibility of undertaking CPET and the relationship between CPET and quality of life measurements in a well-defined population of mild and moderate IPF patients.

Methods

A prospective, single-centre observational study.

Results

Thirty-two IPF patients (mild n = 23, moderate n = 9) participated in the study, n = 13 mild patients attended for repeat CPET testing at 12 months. At baseline, total K-BILD scores and total IPF-PROM scores significantly correlated with 6MWT distance, but not with baseline FVC % predicted, TLco % predicted, baseline or minimum SpO₂. VO₂ peak/kg at AT positively correlated with total scores, breathlessness/activity and chest domains of the K-BILD questionnaire (p < 0.05). VO₂ peak significantly correlated with total IPF PROM scores and wellbeing domains (p < 0.05), with a trend towards statistical significance for total IPF-PROM and VO₂ peak/kg at anaerobic threshold (p = 0.06).

There was a statistically significant reduction in FVC% predicted at 12 months follow up, although the mean absolute decline was < 10% (p < 0.05). During this period VO₂ peak significantly reduced (21.6 ml/kg/min ± 2.9 vs 19.1 ± 2.8; p = 0.017), with corresponding reductions in total K-BILD and breathlessness/activity domains that exceeded the MCID for responsiveness. Lower baseline VO₂ peak/kg at anaerobic threshold correlated with greater declines in total K-BILD scores (r =  − 0.62, 0.024) at 12 months. Whilst baseline FVC% predicted or TLco % predicted did not predict change in health status,

Conclusion

We have shown that it is feasible to undertake CPET in patients with mild to moderate IPF.

CPET measures of VO₂ peak correlated with both baseline and change in K-BILD measurements at 1 year, despite relatively stable standard lung function (declines of < 10% in FVC), suggesting its potential sensitivity to detect physiological changes underlying health status.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01520-8.

The prognostic value of cardiopulmonary exercise testing in interstitial lung disease: a systematic review

The heterogeneity of interstitial lung disease (ILD) results in prognostic uncertainty concerning end-of-life discussions and optimal timing for transplantation. Effective prognostic markers and prediction models are needed. Cardiopulmonary exercise testing (CPET) provides a comprehensive assessment of the physiological changes in the respiratory, cardiovascular and musculoskeletal systems in a controlled laboratory environment. It has shown promise as a prognostic factor for other chronic respiratory conditions. We sought to evaluate the prognostic value of CPET in predicting outcomes in longitudinal studies of ILD.

MEDLINE, Embase and the Cochrane Database of Systematic Reviews were used to identify studies reporting the prognostic value of CPET in predicting outcomes in longitudinal studies of ILD. Study quality was assessed using the Quality in Prognosis Study risk of bias tool.

Thirteen studies were included that reported the prognostic value of CPET in ILD. All studies reported at least one CPET parameter predicting clinical outcomes in ILD, with survival being the principal outcome assessed. Maximum oxygen consumption, reduced ventilatory efficiency and exercise-induced hypoxaemia were all reported to have prognostic value in ILD. Issues with study design (primarily due to inherent problems of retrospective studies, patient selection and presentation of numerous CPET parameters), insufficient adjustment for important confounders and inadequate statistical analyses limit the strength of the conclusions that can be drawn at this stage.

There is insufficient evidence to confirm the value of CPET in facilitating “real-world” clinical decisions in ILD. Additional prospective studies are required to validate the putative prognostic associations reported in previous studies in carefully phenotyped patient populations.

There is presently insufficient evidence to confirm the value of CPET in facilitating “real-world” clinical decisions in ILD. Additional prospective studies are required to validate the putative prognostic associations reported in previous studies.https://bit.ly/3dfp5kq

Cardiopulmonary Exercise Testing Allows Discrimination Between Idiopathic Non-specific Interstitial Pneumonia and Idiopathic Pulmonary Fibrosis in Mild to Moderate Stages of the Disease

It is unclear whether there are cardiopulmonary exercise testing (CPET) parameters which may indicate poor prognosis in the early course of fibrosing interstitial lung disease. 27 untreated consecutive subjects (13 idiopathic non-specific interstitial pneumonia (iNSIP), 14 idiopathic pulmonary fibrosis (IPF); 19 male; age 69 ± 10 years) were enrolled in this observational pilot study. Subjects underwent routine pulmonary function testing and CPET. Statistically, the t test and the Mann-Whitney-U test were applied in the presence of normal and non-normal distribution (according to Shapiro-Wilk), respectively. Analyzing the whole cohort, only mild functional impairments were determined. Comparison of iNSIP and IPF groups detected significant differences for the CPET parameters V'O₂Peak[%pred] (p = 0.011), V'O₂/kgPeak (p = 0.033), Watt[%pred] (p = 0.048), V'E/V'CO₂ (Rest: p = 0.016; AT: p = 0.011; Peak: p = 0.019; Slope: p = 0.040), V'E/V'O₂ (Rest: p = 0.033 AT: p = 0.014; Peak: p = 0.035). CPET parameters may indicate IPF-specific impairments even in mild disease. It may be hypothesized that these parameters are early biomarkers of poor prognosis.

Using SpO2 Recovery Index after a 6-Minute Walk Test to Predict Respiratory-Related Events in Hospitalized Patients with Interstitial Pneumonia

Although the prognostic factors of interstitial pneumonia (IP) patients have been reported, IP has poor prognosis. Hospitalized patients with IP have severely impaired pulmonary diffusion capacity and prominent desaturation. We hypothesized that determining oxygen saturation recovery (SpO₂ recovery index) after the 6-minute walk test (6MWT) can provide additional prognostic information regarding rehospitalization for respiratory-related events. We evaluated 73 IP patients at our hospital for demographic characteristics, pulmonary function tests and 6MWT. The Kaplan–Meier method was used to estimate rehospitalisation for respiratory-related events using SpO₂ recovery index. Cox regression analysis revealed a relationship between SpO₂ recovery index and rehospitalisation. The optimum cutoff value of SpO₂ recovery index was 4% (sensitivity, 71.4%; specificity, 79.2%). SpO₂ recovery index was most closely related to pulmonary diffusion capacity (r = 0.684, P < 0.001). In a multivariable model, it was the strongest independent predictor of rehospitalisation for respiratory-related events (hazard ratio, 0.3; 95% confidence interval, 0.10–0.90; P = 0.032). In this study, we estimated pulmonary diffusion capacity using SpO₂ recovery index values obtained from 6MWT. A SpO₂ recovery index of <4% can be useful in predicting rehospitalisation for respiratory-related events.

Effect of pre-discharge cardiopulmonary fitness on outcomes in patients with ST-elevation myocardial infarction after percutaneous coronary intervention

BACKGROUND

The purpose of this study was to analyze cardiopulmonary fitness in Phase I cardiac rehabilitation on the prognosis of patients with ST-Elevation Myocardial Infarction (STEMI) after percutaneous coronary intervention (PCI).

METHODS

The study enrolled a total of 499 STEMI patients treated with PCI between January 2015 and December 2015. Patients were assigned to individualized exercise prescriptions (IEP) group and non-individualized exercise prescriptions (NIEP) group according to whether they accept or refuse individualized exercise prescriptions. We compared the incidence of major cardiovascular events between the two groups. IEP group were further divided into two subgroups based on prognosis status, namely good prognosis (GP) group and poor prognosis (PP) group. Key cardio-pulmonary exercise testing (CPX) variables that may affect the prognosis of patients were identified through comparison of the cardio-respiratory fitness (CRF).

RESULTS

There is no significant difference in the incidence of cardio-genetic death, re-hospitalization, heart failure, stroke, or atrial fibrillation between the IEP and the NIEP group. But the incidence of total major adverse cardiac events (MACE) was significantly lower in the IEP group than in the NIEP group (P = 0.039). The oxygen consumption (VO₂) at ventilation threshold (VT), minute CO₂ ventilation (E-VCO₂), margin of minute ventilation carbon dioxide production (△CO₂)_, rest partial pressure of end-tidal carbon dioxide(R-P_ETCO₂), exercise partial pressure of end-tidal carbon dioxide(E-P_ETCO₂) and margin of partial pressure of end-tidal carbon dioxide(△P_ETCO₂) were significantly higher in the GP subgroup than in the PP subgroup; and the slope for minute ventilation/carbon dioxide production (V_E/VCO₂) was significantly lower in GP subgroup than in PP subgroup (P = 0.010). The VO₂ at VT, V_E/VCO₂ slope, E-VCO₂, △CO₂, R-P_ETCO₂, E-P_ETCO₂ and margin of partial pressure of end-tidal carbon dioxide CO₂ (△P_ETCO₂) were predictive of adverse events. The VO₂ at VT was an independent risk factor for cardiovascular disease prognosis.

CONCLUSIONS

Individualized exercise prescription of Phase I cardiac rehabilitation reduced the incidence of cardiovascular events in patients with STEMI after PCI. VO₂ at VT is an independent risk factor for cardiovascular disease prognosis, and could be used as an important evaluating indicator for Phase I cardiac rehabilitation.

Comparing effectiveness of prognostic tests in idiopathic pulmonary fibrosis

Introduction: Idiopathic pulmonary fibrosis (IPF) is a debilitating and progressive fibrotic interstitial lung disease often resulting in death over several years. Prediction of disease course or survival remains of keen interest for clinicians and patients though a commonly used test or tool remain elusive. Areas covered: We undertook a comprehensive review of the published literature highlighting prognostic indicators and predictors of survival in IPF. Baseline and longitudinal clinical, functional, histopathologic, and radiologic findings have been extensively studied as prognostic predictors, both individually and in composite models. Recent approaches include automated quantifiable radiologic scoring, circulating biomarkers, and genetic polymorphisms or abnormalities. This review highlights individual and composite predictors and their relative utility in clinical practice and research studies. Expert opinion: There is a growing body of knowledge highlighting readily available individual and composite predictors of outcome, though none have come to the forefront for common clinical use. Recent advances include quantitative imaging analysis, circulating serologic markers, and genetic testing, which may be more standardized and less prone to lead-time bias or related complications and comorbidities.

The impact of combined cardiopulmonary exercise testing and SPECT myocardial perfusion imaging on downstream evaluation and management

OBJECTIVE

The diagnostic yield of combined cardiopulmonary exercise testing (CPET) and myocardial perfusion imaging (MPI) in patients referred for stress testing has received limited study.

METHODS

We evaluated consecutive patients who underwent combined CPET-MPI at a single tertiary referral center between 2011 and 2015. An abnormal CPET was defined as any of the following: reduced oxygen consumption, cardiac output impairment, or pulmonary impairment. Normal MPI was defined as the absence of resting or stress perfusion defect. The primary study outcome was change in clinical decision-making after CPET-MPI including management of pulmonary disease, management of deconditioning, heart failure management, and referral for cardiac catheterization. Outcomes of patients with normal and abnormal MPI were presented based on the specific CPET abnormality.

RESULTS

415 patients were included in the study. Of the 269 patients that had normal MPI, 206 (77%) had abnormal CPET. Patients with abnormal CPET and normal MPI, compared with patients that had normal CPET and normal MPI, were more frequently diagnosed with pulmonary disease (11.7% vs 3.2%, P = .04) and deconditioning (33.5% vs 17.4%, P = .01). Of the 146 patients that had abnormal MPI, 128 (88%) had abnormal CPET. Patients with abnormal CPET and abnormal MPI, compared with patients that had normal CPET and abnormal MPI, did not statistically differ with regard to the study outcome.

CONCLUSION

An abnormal CPET, if the MPI was normal, prompted further evaluation and led to management of pulmonary disease and deconditioning.

8-Foot-Up-and-Go Test is Associated with Hospitalizations and Mortality in Idiopathic Pulmonary Fibrosis: A Prospective Pilot Study

PURPOSE

To assess the prognostic value of the 8-foot-up-and-go test (8-FUGT) in pilot cohort of patients with idiopathic pulmonary fibrosis (IPF).

METHODS

Thirty-four patients with IPF (68 ± 8 years) underwent 8-FUGT at baseline and were followed for up to 40 months. Receiver operating characteristics and age-adjusted Cox hazard ratios (HR) were analyzed for 8-FUGT, hospitalizations, and mortality. Correlation coefficients were determined between 8-FUGT and other exercise tests.

RESULTS

8-FUGT ≥ 6.9 s was found to be associated with hospitalization (sensitivity = 77%, specificity = 76%, p = 0.03) and mortality (sensitivity = 91%, specificity = 70% p = 0.008) in patients with IPF. Categorical models demonstrated that 8-FUGT ≥ 6.9 s was associated with 14.1- (p < 0.001) and 55.4-fold (p = 0.001) increased risks for hospitalization and mortality, respectively. In continuous models, for every 1-s slower performance in the 8-FUGT there were 54% [HR = 1.54, 95% CI (1.11-2.15) p = 0.01] increased risk for hospitalization and 94% [HR = 1.94, 95% CI (1.26-2.99) p = 0.003] increased risk for mortality. 8-FUGT was inversely related to 6-min walk distance (r = - 0.61), peak oxygen consumption (r = - 0.58), and peak work rate (r = - 0.72), all p < 0.001.

CONCLUSIONS

The 8-FUGT was strongly associated with hospitalizations and mortality in patients with IPF, as well as correlated with established prognostic markers. These novel findings suggest a prognostic value of the 8-FUGT for risk stratification, referral to pulmonary rehabilitation, and considering listing for lung transplantation. 8-FUGT is an inexpensive and practical tool that has prospective for implementation in clinical and research settings in IPF. Future prospective studies should evaluate the effect of changes in 8-FUGT on clinical outcomes.

TRIAL REGISTRATION

NCT01499745, Clinicaltrials.gov.

A randomized cross-over trial on the direct effects of oxygen supplementation therapy using different devices on cycle endurance in hypoxemic patients with Interstitial Lung Disease

Background

In patients with interstitial lung disease (ILD) a cardinal feature is exercise intolerance, often associated with significant dyspnea and severe hypoxemia. Supplemental oxygen therapy may be offered during exercise. The Oxymizer is a nasal cannula with an incorporated reservoir with the potential to deliver higher oxygen doses to the patient.

Objective

The primary aim was to investigate the effect of supplemental oxygen delivered via Oxymizer compared to a conventional nasal cannula (CNC) in patients with ILD during constant work rate tests (CWRT). Secondary aim was to evaluate effects on oxygen saturation (SpO₂), dyspnea and heart rate at isotime.

Methods

In this randomized crossover study 24 ILD patients established on long-term oxygen treatment were included. Patients performed four cycling CWRT at 70% of their peak work rate; twice with the Oxymizer and twice with the CNC.

Results

Twenty-one patients finished all CWRTs (age 60 ± 10.9 years, VC 55.4 ± 23.0%predicted). Cycle endurance time was significantly higher while using the Oxymizer compared to CNC (718 ± 485 vs. 680 ± 579 seconds, p = 0.02), and SpO₂ at isotime was significantly higher while using the Oxymizer (85.5 ± 6.7 vs. 82.8± 7.2, p = 0.01). Fifteen of the 21 (71%) patients cycled longer with the Oxymizer. There were no significant differences for dyspnea and heart rate.

Conclusions

Supplemental oxygen provided by the Oxymizer significantly, but modestly, improved cycle endurance time and SpO₂ at isotime in ILD patients compared to CNC.

Safety of exertional desaturation in idiopathic pulmonary fibrosis: An electrocardiography study

INTRODUCTION

Exertional desaturation is a cardinal manifestation of idiopathic pulmonary fibrosis (IPF) which raises concerns for serious complications.

OBJECTIVES

To evaluate the safety of clinically significant desaturation (CSD) during exercise and to assess whether abnormal electrocardiographic (ECG) changes are associated with mortality and hospitalizations in patients with IPF.

METHODS

Thirty-four IPF patients (68 ± 8 years, 35% women) underwent maximal cycle cardiopulmonary exercise testing (CPET) using 12-lead ECG and pulse oximetry (SpO₂ ) and were followed up to 40 months. CSD was considered as SpO₂ <95% or decline from baseline ≥5%. The level of agreement between abnormal ECG changes and CSD was evaluated. Risks for mortality and hospitalizations were assessed in relation to abnormal ECG changes.

RESULTS

All patients completed CPET without adverse events or life-threating ECG changes. Comparing rest to exercise conditions, the prevalence of mild ventricular arrhythmia rose from 3% to 18% (P = .025) and CSD rose from 21% to 79% (P < .001). There was no agreement between the prevalence of arrhythmia and CSD during exercise (kappa = -.065, χ²  = .72, P = .40). A trend for lower prevalence was observed in ST-T segment deviation during exercise. Resting and exercise ECG abnormalities were not associated with mortality or hospitalizations during the follow-up.

CONCLUSIONS

CSD during CPET was not associated with ventricular arrhythmias, ischemia, or complications in patients with IPF. These findings suggest that CPET is generally a safe procedure for IPF, although carefully monitoring for signs and symptoms including ECG is strongly recommended. Additional research is warranted to confirm these results.

Validity of Ultrasound Lung Comets for Assessment of the Severity of Interstitial Pneumonia

OBJECTIVES

Ultrasound (US) lung comets are often observed in patients with interstitial lung disease or congestive heart failure, but few studies have explored the clinical importance of US lung comets in patients with the former condition. We explored whether the US lung comet number could be used to assess the severity of interstitial pneumonia.

METHODS

Forty stable patients with interstitial pneumonia were examined. Lung comets evident on transthoracic US imaging in 12 selected regions of the posterior chest wall were analyzed. We defined lung comets accompanied by thickened and irregular pleural lines as interstitial US lung comets; these predominated in patients with interstitial pneumonia. The total number of interstitial US lung comets was correlated with the data from chest high-resolution computed tomography, pulmonary function tests, serologic tests, and the 6-minute walk test.

RESULTS

The 40 patients included 16 with idiopathic pulmonary fibrosis and 24 with nonspecific interstitial pneumonia. Thirty-four patients had interstitial US lung comets, which were more common in the lower than the upper lung area. Good correlations were evident between the lung comet number and the extent of the reticular pattern on chest high-resolution computed tomography (r = 0.710; P < .01), predicted forced vital capacity (r = -0.614; P < .01), and lung diffusion capacity for carbon monoxide (r = -0.577; P < .01). Notably, the lung comet number had a strong negative correlation with the percutaneous oxygen saturation level after the 6-minute walk test (r = -0.751; P < .01).

CONCLUSIONS

The number of interstitial US lung comets evident on transthoracic US imaging may be a valuable marker of disease severity in patients with interstitial pneumonia.

Prognostic Role of Cardiopulmonary Exercise Testing in Clinical Practice

Risk stratification is a mainstay in the care of cardiac and pulmonary disorders, as the identification of adverse outcomes helps provide measures to improve survival and quality of life. The cardiopulmonary exercise test is a useful prognostic tool in the clinical evaluation of several pathological conditions, such as heart diseases, respiratory disorders, and pulmonary hypertension. If not contraindicated, a cardiopulmonary exercise test should always be performed and integrated with clinical, laboratory, and hemodynamic parameters to better stratify patient risk. In heart failure, the cardiopulmonary exercise test is important in all the stages of patient management, from diagnosis to risk assessment. Different exercise variables have been advocated as prognostic indicators in this condition, including peak oxygen uptake, ventilatory efficiency, respiratory patterns, and identification of the anaerobic threshold. The prognostic role of the cardiopulmonary exercise test in heart failure is amplified when included in multiparametric risk stratification methodology, currently considered the best method to assess patient outcome. In respiratory disorders and in pulmonary hypertension, cardiopulmonary exercise test parameters, focusing on ventilatory performance during exercise, may help evaluate the risk of adverse events. Finally, the cardiopulmonary exercise test may help define the presence of coexisting cardiac and respiratory disorders, a combination that leads to increased rates of disability and mortality.

Ventilatory response to exercise in cardiopulmonary disease: the role of chemosensitivity and dead space

The lungs and heart are irrevocably linked in their oxygen (O₂) and carbon dioxide (CO₂) transport functions. Functional impairment of the lungs often affects heart function and vice versa The steepness with which ventilation (V'_E) rises with respect to CO₂ production (V'_CO2 ) (i.e. the V'_E/V'_CO2 slope) is a measure of ventilatory efficiency and can be used to identify an abnormal ventilatory response to exercise. The V'_E/V'_CO2 slope is a prognostic marker in several chronic cardiopulmonary diseases independent of other exercise-related variables such as peak O₂ uptake (V'_O2 ). The V'_E/V'_CO2 slope is determined by two factors: 1) the arterial CO₂ partial pressure (P_aCO2 ) during exercise and 2) the fraction of the tidal volume (V_T) that goes to dead space (V_D) (i.e. the physiological dead space ratio (V_D/V_T)). An altered P_aCO2 set-point and chemosensitivity are present in many cardiopulmonary diseases, which influence V'_E/V'_CO2 by affecting P_aCO2 Increased ventilation-perfusion heterogeneity, causing inefficient gas exchange, also contributes to the abnormal V'_E/V'_CO2 observed in cardiopulmonary diseases by increasing V_D/V_T During cardiopulmonary exercise testing, the P_aCO2 during exercise is often not measured and V_D/V_T is only estimated by taking into account the end-tidal CO₂ partial pressure (P_ETCO2 ); however, P_aCO2 is not accurately estimated from P_ETCO2 in patients with cardiopulmonary disease. Measuring arterial gases (P_aO2 and P_aCO2 ) before and during exercise provides information on the real (and not "estimated") V_D/V_T coupled with a true measure of gas exchange efficiency such as the difference between alveolar and arterial O₂ partial pressure and the difference between arterial and end-tidal CO₂ partial pressure during exercise.

Exertional dyspnoea in interstitial lung diseases: the clinical utility of cardiopulmonary exercise testing

Interstitial lung diseases (ILDs) represent a heterogeneous group of pathologies characterised by alveolar and interstitial damage, pulmonary inflammation (usually associated with fibrosis), decreased lung function and impaired gas exchange, which can be attributed to either a known or an unknown aetiology. Dyspnoea is one of the most common and disabling symptoms in patients with ILD, significantly impacting quality of life. The mechanisms causing dyspnoea are complex and not yet fully understood. However, it is recognised that dyspnoea occurs when there is an imbalance between the central respiratory efferent drive and the response of the respiratory musculature. The respiratory derangement observed in ILD patients at rest is even more evident during exercise. Pathophysiological mechanisms responsible for exertional dyspnoea and reduced exercise tolerance include altered respiratory mechanics, impaired gas exchange, cardiovascular abnormalities and peripheral muscle dysfunction.

This review describes the respiratory physiology of ILD, both at rest and during exercise, and aims to provide comprehensive and updated evidence on the clinical utility of the cardiopulmonary exercise test in the assessment and management of these pathological entities. In addition, the role of exercise training and pulmonary rehabilitation programmes in the ILD population is addressed.

A Systematic Review of the Role of Dysfunctional Wound Healing in the Pathogenesis and Treatment of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive interstitial lung disorder showcasing an interaction between genetic predisposition and environmental risks. This usually involves the coaction of a mixture of cell types associated with abnormal wound healing, leading to structural distortion and loss of gas exchange function. IPF bears fatal prognosis due to respiratory failure, revealing a median survival of approximately 2 to 3 years. This review showcases the ongoing progress in understanding the complex pathophysiology of IPF and it highlights the latest potential clinical treatments. In IPF, various components of the immune system, particularly clotting cascade and shortened telomeres, are highly involved in disease pathobiology and progression. This review also illustrates two US Food and Drug Administration (FDA)-approved drugs, nintedanib (OFEV, Boehringer Ingelheim, Ingelheim am Rhein, Germany) and pirfenidone (Esbriet, Roche, Basel, Switzerland), that slow IPF progression, but unfortunately neither drug can reverse the course of the disease. Although the mechanisms underlying IPF remain poorly understood, this review unveils the past and current advances that encourage the detection of new IPF pathogenic pathways and the development of effective treatment methods for the near future.

Use of exercise testing in the evaluation of interventional efficacy: an official ERS statement

This document reviews 1) the measurement properties of commonly used exercise tests in patients with chronic respiratory diseases and 2) published studies on their utilty and/or evaluation obtained from MEDLINE and Cochrane Library searches between 1990 and March 2015.

Exercise tests are reliable and consistently responsive to rehabilitative and pharmacological interventions. Thresholds for clinically important changes in performance are available for several tests. In pulmonary arterial hypertension, the 6-min walk test (6MWT), peak oxygen uptake and ventilation/carbon dioxide output indices appear to be the variables most responsive to vasodilators. While bronchodilators do not always show clinically relevant effects in chronic obstructive pulmonary disease, high-intensity constant work-rate (endurance) tests (CWRET) are considerably more responsive than incremental exercise tests and 6MWTs. High-intensity CWRETs need to be standardised to reduce interindividual variability. Additional physiological information and responsiveness can be obtained from isotime measurements, particularly of inspiratory capacity and dyspnoea. Less evidence is available for the endurance shuttle walk test. Although the incremental shuttle walk test and 6MWT are reliable and less expensive than cardiopulmonary exercise testing, two repetitions are needed at baseline. All exercise tests are safe when recommended precautions are followed, with evidence suggesting that no test is safer than others.

Principles of rehabilitation and reactivation: interstitial lung disease, sarcoidosis and rheumatoid disease with respiratory involvement

The interstitial lung diseases (ILDs) are characterised by dyspnoea on exertion, exercise-induced hypoxaemia, reduced skeletal muscle function and exercise intolerance. Evidence from nine randomised controlled trials shows that pulmonary rehabilitation improves exercise capacity, dyspnoea and quality of life in ILD, with moderately large effect sizes from 0.59 to 0.68. Participants with idiopathic pulmonary fibrosis, the most common and most progressive of the ILDs, achieve benefits in exercise capacity and quality of life that are of equal magnitude to those seen in other ILDs, with effect sizes from 0.59 to 0.75. Whole body exercise training is a core component of pulmonary rehabilitation for ILD. The standard exercise prescription used for other chronic lung diseases is effective in ILD, including 8 weeks of training with at least two supervised sessions per week and at least 30 min of aerobic training per session. However, the unique presentation and underlying pathophysiology of ILD may require modifications of the exercise prescription for individual patients. Those with connective tissue disease may present with joint pain and stiffness that require modification of the standard exercise prescription, including reduction in weight-bearing exercise. Some patients with severe disease may present with distressing dyspnoea that limits the intensity or progression of training. Because exercise-induced hypoxaemia is common in ILD and more severe than seen in other chronic lung diseases, pulmonary rehabilitation should be provided in a setting where supplemental oxygen therapy is available. Pulmonary rehabilitation programs offer the opportunity to address other critical aspects of ILD care, including management of comorbidities, symptoms and mood.

Cardiorespiratory responses to 6-minute walk test in interstitial lung disease: not always a submaximal test

BACKGROUND

The 6-minute walk test (6 MWT) is used to measure exercise capacity and assess prognosis in interstitial lung disease (ILD). Although the 6 MWT is usually considered to be a test of submaximal exercise capacity in ILD, the physiological load imposed by this test is not well described and 6 MWT outcomes are poorly understood. This study aimed to compare cardiorespiratory responses to 6 MWT and cardiopulmonary exercise test (CPET) in people with ILD.

METHODS

47 participants with ILD (27 idiopathic pulmonary fibrosis (IPF), mean age 71 (SD 12) years, diffusing capacity for carbon monoxide (TLCO) 49(15) %predicted) undertook CPET and 6 MWT on the same day in random order. Oxygen uptake (VO(2)), ventilation (VE) and carbon dioxide production (VCO2) were assessed during each test using a portable metabolic cart.

RESULTS

The VO(2)peak during the 6 MWT was lower than during CPET (1.17(0.27) vs 1.30(0.37) L.min-1, p = 0.001), representing an average of 94% (range 62-135%) of CPET VO(2)peak. Achieving a higher percentage of CPET VO(2)peak on 6 MWT was associated with lower TLCO %predicted (r = -0.43, p = 0.003) and more desaturation during walking (r = -0.46, p = 0.01). The VEpeak and VCO(2)peak were significantly lower during 6 MWT than CPET (p < 0.05). However, participants desaturated more during the 6 MWT (86(6)% vs 89(4)%, p < 0.001). The degree of desaturation was not affected by the percent of peak VO2 achieved during the 6 MWT. Responses were similar in the subgroup with IPF.

CONCLUSIONS

On average, the 6 MWT elicits a high but submaximal oxygen uptake in people with ILD. However the physiological load varies between individuals, with higher peak VO2 in those with more severe disease that may match or exceed that achieved on CPET. The 6 MWT is not always a test of submaximal exercise capacity in people with ILD.

Idiopathic pulmonary fibrosis and coronary artery disease

Idiopathic pulmonary fibrosis (IPF) is defined as a chronic fibrosing interstitial disease of unknown cause, limited to the lungs, and associated with the histopathologic and/or radiologic pattern of usual interstitial pneumonia (UIP); it generally progresses into respiratory failure and death. Although progression of the disease is the most common cause of death, there are increasing reports of its association with other pathologies has been reported: e.g., IPF patients seem more susceptible to cardiovascular diseases. Therefore, other pathologies might also influence the natural course. In this paper, we describe a case of IPF and coronary artery disease (CAD). We emphasize the importance of cardiopulmonary exercise test (CPET) as a useful procedure to monitor disease progression in IPF patients. We also stress the importance of a careful analysis of variables measured for an accurate interpretation of the clinical picture and an improvement of the clinical management of patients. Moreover, we suggest that a careful assessment of CPET parameters may additionally help in the early detection of high cardiovascular ischemic risk.

Influence of radiological emphysema on lung function test in idiopathic pulmonary fibrosis

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is one of the most frequent interstitial lung disease. Emphysema can be associated with IPF as described in the «Combined pulmonary fibrosis and emphysema» syndrome.

AIM

The primary endpoint of this retrospective cohort study was to evaluate the impact of the association of IPF and emphysema on lung function tests parameters (FVC, TLC, FEV1, FEV1/FVC and DLCO). The secondary endpoint was to assess the impact of the associated radiological emphysema on lung function parameters used in the du Bois prognostic score recently developed by Ron du Bois et al.

METHOD

We retrospectively reviewed the medical files of 98 patients with lung fibrosis who were followed in our University Hospital with access to pharmacological studies and lung transplantation from 1981 to 2011. Fifty six patients were considered for analysis. The collected data included gender, age, smoking history and respiratory hospitalizations. We also analysed their pulmonary functional parameters along with radiological characteristics, in particular the presence of emphysema which was assessed on thoracic high resolution CT scan. The du Bois score was retrospectively calculated from these data.

RESULTS

TLC and FVC at diagnosis were significantly higher in the IPF-E group compared to the IPF group (respectively 86.6 ± 17.2% pv versus 72.0 ± 15.0% pv; p: 0.004 and 86.8 ± 18.4% pv versus 72.6 ± 20.6% pv; p: 0.020). The [Formula: see text] used in the calculation of the du Bois prognostic score was significantly higher in the IPF-E group. By cons, [Formula: see text] was not statistically different between the two groups.

CONCLUSION

Radiological emphysema associated with IPF had an impact on pulmonary function tests. Despite this difference, the du Bois score was not statistically different between these two groups. Nevertheless, after one year of follow up, the patients with emphysema were in a subclass with a lower mortality rate than those without emphysema.

Impaired chronotropic response to 6-min walk test and reduced survival in interstitial lung disease

BACKGROUND

Reduced chronotropic response to maximal exercise has been associated with poor survival in people without respiratory disease. The contribution of chronotropic response to exercise limitation and survival in interstitial lung disease (ILD) is not well defined. This study investigated the relationships between chronotropic response during 6-min walk test, exercise capacity and survival in ILD.

METHODS

Eligible participants had ILD, were ambulant and free of heart failure and beta blocker therapy. Chronotropic response during the 6-min walk test was defined as peak heart rate (HR) minus resting HR. Survival was recorded at four years.

RESULTS

Sixty-two participants (40 idiopathic pulmonary fibrosis) were included, with mean (SD) TLCO 50(18)% predicted and 6-min walk distance (6MWD) 377 (127) metres. A smaller chronotropic response was associated with reduced 6MWD (r = 0.65, p < 0.001). Independent predictors of 6MWD were chronotropic response, peak oxygen uptake on cardiopulmonary exercise test; right ventricular systolic pressure on echocardiogram; and age. This model explained 83% of the variance in 6MWD, with 24% of the variance attributable to chronotropic response. A chronotropic response during 6-min walk test of less than 20 beats per minute was an independent predictor of death at four years (odds ratio 10.71, 95% confidence interval 2.67-42.94) in a model that also included oxygen desaturation and forced vital capacity.

CONCLUSIONS

Impaired chronotropic response to 6-min walk test is associated with reduced 6MWD and reduced survival in ILD, independent of physical fitness and pulmonary hypertension. Investigation of the mechanisms underlying attenuated HR response to exercise in ILD is warranted.

The diagnosis of idiopathic pulmonary fibrosis and its complications

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a devastating, progressive condition with a median survival of 2.8 - 4 years from diagnosis. Clinicians confronted with a patient with fibrosing lung disease need to be reliably able to distinguish IPF from other diffuse parenchymal lung diseases. Furthermore, they need to be able to gauge prognosis, evaluate timing of interventions including referral for transplant, assess reliably the effectiveness of treatment and be able to detect rapidly the development of disease complications.

OBJECTIVE/METHOD

This paper provides an overview of currently available diagnostic tests for IPF and its complications and evaluates the possible future role of candidate biomarkers in the diagnosis and assessment of patients with IPF. A literature search was performed for papers evaluating diagnostic tests in the diagnosis of IPF and its complications.

CONCLUSION

Computed tomography combined with clinical data is sufficient for diagnosing IPF in approximately two-thirds of patients with the condition. For the remaining patients, histological assessment is important in achieving a precise diagnosis. Serial measurements of carbon monoxide diffusing capacity and forced vital capacity provide the best prognostic indicator in IPF. Potential biomarkers for diagnosing IPF include KL-6, MMP1 and MMP7. Brain naturetic peptide shows promise as a non-invasive screening tool for the diagnosis of IPF-associated pulmonary hypertension.

Cardiopulmonary exercise testing in lung transplantation: a review

There has been an increase in lung transplantation in the USA. Lung allocation is guided by the lung allocation score (LAS), which takes into account one measure of exercise capacity, the 6-minute walk test (6MWT). There is a paucity of data regarding the role and value of cardiopulmonary stress test (CPET) in the evaluation of lung transplant recipients while on the transplant waiting list and after lung transplantation. While clearly there is a need for further prospective investigation, the available literature strongly suggests a potential role for CPET in the setting of lung transplant.

Predictive properties of different multidimensional staging systems in patients with chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) is considered to be a respiratory disease with systemic manifestations. Some multidimensional staging systems, not based solely on the level of airflow limitation, have been developed; however, these systems have rarely been compared.

Methods

We previously recruited 150 male outpatients with COPD for an analysis of factors related to mortality. For this report, we examined the discriminative and prognostic predictive properties of three COPD multidimensional measurements. These indices were the modified BODE (mBODE), which includes body mass index, airflow obstruction, dyspnea, and exercise capacity; the ADO, composed of age, dyspnea, and airflow obstruction; and the modified DOSE (mDOSE), comprising dyspnea, airflow obstruction, smoking status, and exacerbation frequency.

Results

Among these indices, the frequency distribution of the mBODE index was the most widely and normally distributed. Univariate Cox proportional hazards analyses revealed that the scores on three indices were significantly predictive of 5-year mortality of COPD (P < 0.001). The scores on the mBODE and ADO indices were more significantly predictive of mortality than forced expiratory volume in 1 second, the Medical Research Council dyspnea score, and the St. George’s Respiratory Questionnaire total score. However, peak oxygen uptake on progressive cycle ergometry was more significantly related to mortality than the scores on the three indices (P < 0.0001).

Conclusion

The multidimensional staging systems using the mBODE, ADO, and mDOSE indices were significant predictors of mortality in COPD patients, although exercise capacity had a more significant relationship with mortality than those indices. The mBODE index was superior to the others for its discriminative property. Further discussion of the definition of disease severity is necessary to promote concrete multidimensional staging systems as a new disease severity index in guidelines for the management of COPD.

Medical Research Council dyspnea scale does not relate to fibroblast foci profusion in IPF

BACKGROUND

In Idiopathic pulmonary fibrosis (IPF) irreversibly progressive fibrosing parenchymal damage, leads to defects in mechanics and gas exchange, manifesting with disabling exertional dyspnea. Previous studies have shown a relationship between fibroblast foci (FF) profusion and severity and survival and a relationship between dyspnea grade and severity and outcome. We hypothesized a relationship between Medical Research Council (MRC) dyspnea scale with FF, and a relationship between FF and functional parameters and survival.

METHODS

We retrospectively reviewed 24 histologically documented IPF patients. Profusion of FF was semiquantitatively evaluated by two scores, Brompton and Michigan. Survival analysis was performed by fitting Cox regression models to examine the relationship of the two scores with survival and the non-parametric Spearman correlation coefficient was calculated to describe the relationships of FF scores with dyspnea scores and functional parameters.

RESULTS

No statistically significant correlation between FF scores and the MRC scores was observed (p = 0.96 and p = 0.508 respectively). No significant correlation between FF scores and survival (p = 0.438 and p = 0.861 respectively) or any functional parameter was observed.

CONCLUSIONS

The lack of relationship between the MRC dyspnea scale and the FF might relate to the fact that dyspnea in IPF better reflects the overall of lung damage and its related consequences on mechanics and gas exchange whereas FF, one of its histological hallmarks, may not reflect its entire histology derangement also constrained by the geographically limited sampled tissue. This might be also valid for the observed lack of association between FF and survival or functional parameters.

[Prognostic value of clinical exercise testing in idiopathic pulmonary fibrosis]

Current guidelines for referring patients with idiopathic pulmonary fibrosis (IPF) for lung transplantation, based on resting parameters, are insufficient to predict 3-year mortality. The aim of this study was to determine the prognostic value of cardio-pulmonary exercise testing (CPET) in patients with IPF. A multicentre retrospective study of 3-year outcome was made on 63 adult patients with IPF who underwent CPET with blood gas analysis. Demographic data, resting pulmonary function and CPET parameters were collected to perform a univariate survival analysis. To estimate prognosis at 3 years, a multivariate logistic regression analysis by Kaplan-Meier curves and log-rank tests was performed. Forty-four patients (70%) were alive without lung transplant at the end of the 3-year follow-up: 19 patients (30%) were dead (n=14) or transplanted (n=5). Univariate analysis indicated that: at rest lower TLC, FVC, DLCO and PaCO(2), higher alveolo-arterial gradient for oxygen [P(A-a)O(2)] and pH; at ventilatory threshold (VT) higher VE/VO(2) and VE/VCO(2) and at peak exercise higher VE/VO(2) and VE/VCO(2), higher pH and ΔP(A-a)O(2)/ΔVO(2) (mmHg/L), lower VO(2) peak, PaO(2) and VO(2)/FC were associated with a significantly lower survival at 3 years. The multivariate logistic regression analysis showed that CPT (<65%) and VE/VO(2) at VT (>45) were independently associated with a lower survival at 3 years. Restriction and hyperventilation at ventilatory threshold are major prognostic factors in the course of IPF. CPET with blood gas analysis may have a prognostic value in these patients and initial evaluation of these parameters can help to predict disease progression.

Cardiopulmonary exercise testing: relevant but underused

Cardiopulmonary exercise testing (CPX) is a relatively old technology, but has sustained relevance for many primary care clinical scenarios in which it is, ironically, rarely considered. Advancing computer technology has made CPX easier to administer and interpret at a time when our aging population is more prone to comorbidities and higher prevalence of nonspecific symptoms of exercise intolerance and dyspnea, for which CPX is particularly useful diagnostically and prognostically. These discrepancies in application are compounded by patterns in which CPX is often administered and interpreted by cardiology, pulmonary, or exercise specialists who limit their assessments to the priorities of their own discipline, thereby missing opportunities to distinguish symptom origins. When used properly, CPX enables the physician to assess fitness and uncover cardiopulmonary issues at earlier phases of work-up, which would therefore be especially useful for primary care physicians. In this article, we provide an overview of CPX principles and testing logistics, as well as some of the clinical contexts in which it can enhance patient care.

The future of aerobic exercise testing in clinical practice: is it the ultimate vital sign?

The four traditional vital signs: resting heart rate, blood pressure, respiratory rate and body temperature, serve as the cornerstone of a physical examination. Other assessments such as pain have been proposed as additional vital signs. To this point however, there has been limited consideration for aerobic exercise assessment as a vital sign. A wealth of literature demonstrating the prognostic, diagnostic and interventional value of the aerobic exercise assessment now exists, supporting its use in numerous clinical scenarios. Moreover, the assessment of the aerobic exercise response allows for the manifestation of physiologic abnormalities that are not readily apparent during the collection of resting data. This review will provide evidence supporting the assertion that the aerobic exercise assessment may be afforded vital sign status in future clinical practice.

Clinical and functional outcomes in Middle Eastern patients with idiopathic pulmonary fibrosis

BACKGROUND

Baseline clinical and physiological variables have been described as relevant predictors of survival among patients with idiopathic pulmonary fibrosis (IPF). However, substantial heterogeneity in both survival time and mortality has been observed with many of these predictive factors. The incidence and mortality rates of IPF vary from country to country, with race potentially contributing to such variations.

OBJECTIVE

We sought to describe baseline clinical features to determine their predictive value among Middle Eastern patients diagnosed with IPF.

METHODS

We retrospectively examined 61 patients diagnosed with IPF at a university hospital in Riyadh, Saudi Arabia.

RESULTS

At presentation, most patients exhibited either dyspnea or cough. The median survival time for all patients was 92 months. Diminished survival was significantly associated with finger clubbing (P = 0.01). Factors not influencing survival were age, gender, percent predicted forced vital capacity, percent predicted forced expiratory volume in 1 s, percent predicted total lung capacity, percent predicted diffusion capacity of the lung for carbon monoxide and resting oxygen saturation.

CONCLUSIONS

Finger clubbing is a significant predictive variable and was associated with a 5-fold increase in mortality. Other baseline demographic characteristics as well as pulmonary function tests were not predictive of prognosis in Middle Eastern patients with IPF. It appears that IPF patients of Middle Eastern descent have a longer median survival curve compared to other races.

MRC chronic Dyspnea Scale: Relationships with cardiopulmonary exercise testing and 6-minute walk test in idiopathic pulmonary fibrosis patients: a prospective study

Background

Exertional dyspnea is the most prominent and disabling feature in idiopathic pulmonary fibrosis (IPF). The Medical Research Chronic (MRC) chronic dyspnea score as well as physiological measurements obtained during cardiopulmonary exercise testing (CPET) and the 6-minute walk test (6MWT) are shown to provide information on the severity and survival of disease.

Methods

We prospectively recruited IPF patients and examined the relationship between the MRC score and either CPET or 6MWT parameters known to reflect physiologic derangements limiting exercise capacity in IPF patients

Results

Twenty-five patients with IPF were included in the study. Significant correlations were found between the MRC score and the distance (r = -.781, p < 0.001), the SPO₂ at the initiation and the end (r = -.542, p = 0.005 and r = -.713, p < 0.001 respectively) and the desaturation index (r = .634, p = 0.001) for the 6MWT; the MRC score and VO₂ peak/kg (r = -.731, p < 0.001), SPO₂ at peak exercise (r = -. 682, p < 0.001), VE/VCO₂ slope (r = .731, p < 0.001), VE/VCO₂ at AT (r = .630, p = 0.002) and the Borg scale at peak exercise (r = .50, p = 0.01) for the CPET. In multiple logistic regression analysis, the only variable independently related to the MRC is the distance walked at the 6MWT.

Conclusion

In this population of IPF patients a good correlation was found between the MRC chronic dyspnoea score and physiological parameters obtained during maximal and submaximal exercise testing known to reflect ventilatory impairment and exercise limitation as well as disease severity and survival. This finding is described for the first time in the literature in this group of patients as far as we know and could explain why a simple chronic dyspnea score provides reliable prognostic information on IPF.

Paraquat (PQ)-induced pulmonary fibrosis increases exercise metabolic cost, reducing aerobic performance in rats

Rats exposed to the quaternary herbicide paraquat (PQ) exhibit oxidative stress and lung injury. In the present study, we investigated the effect of multiple exposures to PQ on aerobic performance during progressive exercise on a treadmill in rats. PQ was dissolved in saline (SAL) (10 mg/ml) and administered intraperitoneally 7 mg/kg body wt to Wistar rats (n = 5) once a week for one month. Control rats received SAL (0.7 ml/kg body wt., intraperitoneally, n = 5) over the same time period. The animals were submitted to aerobic evaluation on a treadmill using a progressive protocol until fatigue prior to the administration of the first dose of PQ or SAL and repeated at 1 week and 40 days following the last dose of the herbicide. Twenty-four hours after the last performance tests, the animals were sacrificed, lungs removed and divided in two groups: PQ and SAL for histopathological analysis. The animals exposed to PQ exhibited decrease in aerobic performance and mechanical efficiency (ME) as well as increase in oxygen consumption during exercise in comparison to the controls forty days after the last dose of PQ. Lung histologic changes included atelectasis, interstitial edema, and inflammation cells in PQ group. The collagen system fibers, fraction area of alveolar collapse and influx of polymorphonuclear (PMN) cells in lung parenchyma were higher in PQ compared to SAL. In conclusion, multiple exposures to PQ induce pulmonary fibrosis, reduce the aerobic performance and mechanical efficiency and increase the metabolic cost of exercise in rats.

Exercise limitation in interstitial lung disease - mechanisms, significance and therapeutic options

Exercise limitation is a cardinal feature of the interstitial lung diseases and is frequently associated with marked dyspnoea on exertion. People with interstitial lung disease exhibit a rapid, shallow breathing pattern during exercise that worsens as disease progresses. Despite this, ventilatory mechanics are not the major limitation to exercise in most patients, with impaired gas exchange and circulatory limitation playing a more important role. Peripheral and respiratory muscle dysfunction may also contribute to impaired exercise tolerance, either due to systemic manifestations of the underlying disease, treatment side-effects or deconditioning. Measures of exercise capacity or desaturation obtained from maximal and submaximal exercise tests are good predictors of survival in patients with idiopathic pulmonary fibrosis. However, to date few pharmaceutical treatments have affected exercise outcomes despite improvements in other important clinical markers. Supplemental oxygen acutely improves exercise capacity in interstitial lung disease and is recommended for hypoxic patients, although quality of life or survival benefits have not yet been demonstrated. Exercise training improves walking capacity and dyspnoea in short-term trials and is useful to maximize functional capacity. The role of exercise testing in the routine management of patients with interstitial lung disease is not clearly defined. However, given the poor prognosis in patients with idiopathic pulmonary fibrosis and the marked variation in clinical course, assessment of exercise capacity may provide useful information for both clinicians and patients when evaluating the risks and benefits of new treatments. The extent of resting or exercise-induced hypoxia in patients with interstitial lung disease may influence the selection of an appropriate exercise test, and oxygen administration should be standardized on repeat testing.