Haemodynamic responses to exercise in patients with COPD

Area of Science:

• Cardiology
• Pulmonology
• Respiratory Medicine

Background:

• Pulmonary hypertension (PH) is a serious complication of chronic obstructive pulmonary disease (COPD).
• Left ventricular dysfunction and comorbidities were excluded to isolate PH in COPD patients.
• Understanding haemodynamic responses during exercise is crucial for managing COPD-related PH.

Purpose of the Study:

• To determine the prevalence of pre-capillary PH in COPD outpatients.
• To characterize the haemodynamic vascular responses to physical exercise in COPD patients.
• To evaluate the definition of exercise-induced PH in COPD.

Main Methods:

• 98 COPD outpatients underwent right heart catheterisation at rest and during supine exercise.
• Measured parameters included mean pulmonary artery pressure (Ppa), pulmonary capillary wedge pressure (Ppcw), and cardiac output (CO).
• Calculated pulmonary vascular resistance (PVR) and pulmonary artery compliance (PAC); defined PH at rest as mean Ppa ≥25 mmHg and Ppcw <15 mmHg.

Main Results:

• PH prevalence increased with COPD severity (5% in GOLD II, 27% in GOLD III, 53% in GOLD IV).
• Exercise-induced Ppa increase did not differ between PH and non-PH groups.
• Non-PH COPD patients exhibited abnormal haemodynamics (increased PVR, reduced PAC, steeper Ppa/CO and Ppa/W slopes) similar to the PH group.

Conclusions:

• Exercise reveals abnormal haemodynamic responses in the majority of COPD patients, irrespective of resting PH status.
• The definition of exercise-induced PH in COPD should prioritize pressure-flow relationships (slopes of Ppa/CO and Ppa/W) over absolute Ppa values.