Resistive and dynamic exercise stress testing in COPD and IPF candidates to lung transplantation: role of the pulmonary arterial stiffness

Background: Patients with advanced COPD and idiopathic pulmonary fibrosis (IPF) appear to have different pulmonary vascular disease. We phenotype hemodynamic profile in COPD and IPF candidates to lung transplantation (LTx) during resistive and dynamic exercise stress testing (EST) according to the pulmonary arterial stiffness (PAS). Methods: We studied 100 patients (p) awaiting LTx, 56 COPD (58±3 yrs 15F) and 44 IPF (58±7 yrs 22F). All p were submitted to RHC and intravascular ultrasound in medium-sized PAs. We assessed total pulmonary arterial resistance and capacitance (TPR, PAC), TAPSE/sPAP ratio, and local PAS (elastic modulus -EM-: diastolic lumen area×pulse pressure/(systolic-diastolic lumen area)) at rest and during a handgrip (HG) and cycle ergometry (CE). The lower peak of mixed venous oxygen saturation (pSvO2), the higher the circulatory EST limitation. Results: We analyzed all p who had PAOP <15 mmHg at rest and who presented similar respiratory function tests. ILD showed a higher PAS than COPD p (p<0.05) beyond PAP. However, COPD and IPF p reached a similar peak single-point mPAP-CO ratio during both EST. Table shows the hemodynamic profiles during both EST in each group. pSvO2 was associated with PAS and rest TAPSE/sPAP only in COPD p (Figure). Conclusion: PAS and TAPSE/sPAP of COPD p and RV impairment of IPF p would be associated with the circulatory reserve in candidates to LTx, respectively.