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

Impact of HRCT pattern on six-minute walk test in patients with interstitial lung disease-An observational study

Background

Forced vital capacity (FVC) and six-minute walk distance (6MWD) are robust markers in interstitial lung diseases (ILD) to assess severity and prognosis. It is unknown whether high-resolution computed tomography pattern has any independent effect on the exercise capacity in ILD. We compared six-minute walk test (6MWT) parameters between usual interstitial pneumonia (UIP) and non-UIP ILD after adjusting for FVC.

Methods

Data from a tertiary care ILD clinic were retrospectively analysed. Based on HRCT, patients were classified as UIP and non-UIP. 6MWT parameters and FVC were recorded for enrolled patients. 6MWD, distance-saturation product (DSP) and exertional desaturation were compared between UIP and non-UIP, using analysis of covariance (ANCOVA), with per cent predicted FVC as covariate. Patients were grouped as mild (≥70%), moderate (51%-69%) and severe (≤50%) based on FVC severity.

Results

Out of 169 patients enrolled, only patients with all three data points: spirometry, 6MWT and HRCT were included in the analysis (n = 139). UIP group comprised 56 (40.3%), while non-UIP group had 83 (59.7%) patients. More females and lesser smokers were present in non-UIP group. Mean predicted FVC% was similar between the two HRCT groups (P = 0.611) and had a statistically significant, though very weak to weak correlation with 6MWT parameters {6MWD (r = 0.138); pred 6MWD% (r = 0.170); desaturation (r = -0.227); DSP index (r = 0.166)}. Analysis of covariance showed no statistically significant difference in the 6MWT parameters between UIP and non-UIP groups for similar FVC levels.

Conclusion

For a similar level of lung function, exercise capacity was similar for patients with UIP and non-UIP pattern ILD.

Value of Cardiopulmonary Exercise Testing in Prognostic Assessment of Patients with Interstitial Lung Diseases

BACKGROUND

Interstitial lung disease (ILD) is associated with high rates of comorbidities and non-infectious lung disease mortality. Against this background, we aimed to evaluate the prognostic capacity of lung function and cardiopulmonary exercise testing (CPET) in patients with ILD.

MATERIALS AND METHODS

A total of 183 patients with diverse ILD entities were included in this monocentric analysis. Prediction models were determined using Cox regression models with age, sex, body mass index (BMI), and all parameters from pulmonary function testing and CPET. Kaplan-Meier curves were plotted for selected variables.

RESULTS

The median follow-up period was 3.0 ± 2.5 years. Arterial hypertension (57%) and pulmonary hypertension (38%) were the leading comorbidities. The Charlson comorbidity index score was 2 ± 2 points. The 3-year and 5-year survival rates were 68% and 50%, respectively. VO₂peak (mL/kg/min or %pred.) was identified as a significant prognostic parameter in patients with ILD. The cut-off value for discriminating mortality was 61%.

CONCLUSION

The present analyses consistently revealed the high prognostic power of VO₂peak %pred. and other parameters evaluating breathing efficacy (VÉ/VCO₂ @AT und VÉ/VCO₂ slope) in ILD patients. VO₂peak %pred., in contrast to the established prognostic values FVC %pred., DLCO/KCO %pred., and GAP, showed an even higher prognostic ability in all statistical models.

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 ).

Feasibility of cardiopulmonary exercise testing in interstitial lung disease: the PETFIB study

Introduction

Cardiopulmonary exercise testing (CPET) provides a series of biomarkers, such as peak oxygen uptake, which could assess the development of disease status in interstitial lung disease (ILD). However, despite use in research and clinical settings, the feasibility of CPET in this patient group has yet to be established.

Methods

Twenty-six patients with ILD (19 male) were recruited to this study. Following screening for contraindications to maximal exercise, participants underwent an incremental CPET to volitional exhaustion. Feasibility of CPET was assessed by the implementation, practicality, acceptability and demand, thus providing clinical-driven and patient-driven information on this testing procedure.

Results

Of the 26 recruited participants, 24 successfully completed at least one CPET, with 67/78 prospective tests being completed. Contraindications included hypertension, low resting oxygen saturation and recent pulmonary embolism. Of the CPETs undertaken, 63% successfully reached volitional exhaustion, with 31% being terminated early by clinicians due to excessive desaturation. Quantitative and qualitative feedback from participants revealed a positive experience of CPET and desire for it to be included as a future monitoring tool.

Conclusion

CPET is feasible in patients with ILD. Identification of common clinical contraindications, and understanding of patient perspectives will allow for effective design of future studies utilising CPET as a monitoring procedure.