Impact of pulmonary hypertension on exercise performance in patients with interstitial lung disease undergoing evaluation for lung transplantation

Abstract

Background and objective Pulmonary hypertension (PH) is a known complication in patients with interstitial lung disease (ILD). Cardiopulmonary exercise testing (CPET) is an essential tool for the assessment of patients with cardiac and pulmonary diseases due to its prognostic and therapeutic implications. Few studies have evaluated the relationship between CPET response and mean pulmonary artery pressures (mPAP) in interstitial lung disease (ILD). The purpose of the present study was to determine and compare the potential correlations between CPET, 6-minute talk test (6MWT), pulmonary function testing (PFT) and PH in patients with ILD being evaluated for lung transplantation. Methods The present study reviewed patients with ILD who received lung transplantations and had CPETs within two years before transplantation, right heart catheterizations, PFTs and 6MWTs within 4 months of CPET. Results A total of 72 patients with ILD were analyzed; 36% had PH. There were significant correlations between mPAP and CPET parameters in patients with PH; but mPAP had no impact on DLCO% or 6MWD. CPET parameters were able to detect differences between levels of severity of PH through the use of the ratio of minute ventilation to rate of carbon dioxide production (V̇E/V̇CO2) and the partial pressure of end-tidal carbon dioxide (PetCO2). Conclusions This is the first study that analyzes 6MWD, PFT and CPET in patients with ILD awaiting lung transplantation with and without PH. The present study demonstrates the significant impact of PH on exercise capacity and performance in patients with ILD awaiting lung transplantation.

Lung function in relation to six-minute walk test in pulmonary hypertension

“…Total lung capacity measurements obtained through the hilum dilution technique did not offer supplementary information. This is in accordance with previous studies where lung volume measurements offered minimal additional information [40][41][42]. In a study by Armstrong et al [40], the authors were unable to show any relationship between peak exercise capacity and lung volumes in patients suffering from interstitial pulmonary disease with or without pulmonary hypertension.…”

Pulmonary vascular and cardiac impairment in interstitial lung disease

“…Exercising ILD subjects with pulmonary hypertension (but not matched ILD subjects without pulmonary hypertension) showed significantly https://doi.org/10.1183/16000617.0053-2016pronounced ventilatory inefficiency (expressed as increased slope of minute ventilation to carbon dioxide output) both at the anaerobic threshold and during peak exercise [63]. Also, the ventilatory inefficiency in patients with ILD correlated with systolic PAP [59,60], predicted independently the presence of pulmonary hypertension [60], and associated strongly with dyspnoea and exercise limitation [59].…”

Frailty and maximal exercise capacity in adult lung transplant candidates

“…We also examined whether frailty was associated with a number of other measures of exercise performance found to be predictive of reduced exercise capacity and/or poor surgical outcomes in those with pulmonary disease, including: oxygen economy ( ${\dot{\mathrm{V}}\mathrm{normalO}}_2$/Work rate slope), heart rate-oxygen uptake relationship (HR/ ${\dot{\mathrm{V}}\mathrm{normalO}}_2$ slope), reduced breathing reserve, minute ventilation ( ${\dot{\mathrm{normalV}}}_{\mathrm{E}}$), oxygen saturation (SpO 2 ), ventilatory equivalent for carbon dioxide slope ( ${\dot{\mathrm{normalV}}}_{\mathrm{E}}$/ ${\dot{\mathrm{V}}\mathrm{normalCO}}_2$ slope), end tidal CO 2 (ETCO 2 mmHg), heart rate reserve (HRR) and systolic blood pressure (SBP) 5–9 .…”