Affiliation:
1. Medical University of Graz, Department of Internal Medicine, Division of Pulmonology and Ludwig Boltzmann Institute for Lung Vascular Research
2. Medical University of Graz, Diagnostic and Research Institute of Pathology
3. Medical University of Graz, Department of Radiology
4. Medical University of Graz, Institute for Medical Informatics, Statistics and Documentation
Abstract
Abstract
Background
Pulmonary hypertension (PH) is a frequent complication in COPD and it is associated with decreased exercise capacity and poor prognosis. We hypothesized that even in COPD patients without significant PH at rest, abnormal pulmonary hemodynamics during exercise affect exercise capacity.
Methods
Consecutive COPD patients with clinically indicated right heart catheterization and resting mean pulmonary arterial pressure (mPAP) < 25mmHg and age- and sex-matched controls without chronic lung disease who underwent clinical work-up including invasive hemodynamic assessment during exercise were retrospectively analyzed. Chi-square tests were used to evaluate differences between groups for categorical data and Fisher’s exact test or Mann-Whitney-U-tests for continuous variables. Associations were analyzed with Spearman rank correlation tests.
Results
We included n=26 COPD patients (female/male: 16/10, 66±11yr, FEV1: 56±25 %predicted) and n=26 matched controls (FEV1: 96±22 %predicted). At rest, COPD patients presented with slightly increased mPAP (21 (18-23) vs. 17 (14-20) mmHg, p=0.022), and pulmonary vascular resistance (PVR) (2.5 (1.9-3.0) vs. 1.9 (1.5-2.4) WU, p=0.020) as compared to controls. During exercise, COPD patients reached significantly higher mPAP (47 (40-52) vs. 38 (32-44) mmHg, p=0.015) and PVR (3.1 (2.2-3.7) vs. 1.7 (1.1-2.9) WU, p=0.028) values despite lower peak exercise level (50 (50-75) vs. 100 (75-125) Watt, p=0.002). The mPAP/cardiac output slope was increased in COPD vs. controls (6.9 (5.5-10.9) vs. 3.7 (2.4-7.4) mmHg/L/min, p=0.007) and negatively correlated with both peak oxygen uptake (r=-0.46, p=0.007) and 6-minute walk distance (r=-0.46, p=0.001).
Conclusion
Even in the absence of significant PH at rest, COPD patients reveal characteristic abnormalities in pulmonary hemodynamics during exercise, which may represent an important exercise-limiting factor.
Publisher
Research Square Platform LLC