Impact of pulmonary artery pressure on exercise function in severe COPD.
BACKGROUND
Although pulmonary hypertension commonly complicates COPD, the functional consequences of increased pulmonary artery pressures in patients with this condition remain poorly defined.


METHODS
We conducted a cross-sectional analysis of a cohort of 362 patients with severe COPD who were evaluated for lung transplantation. Patients with pulmonary hemodynamics measured by cardiac catheterization and available 6-min walk test results were included. The association of mean pulmonary artery pressure (mPAP) with pulmonary function, echocardiographic variables, and 6-min walk distance was assessed.


RESULTS
The prevalence of pulmonary hypertension (mPAP, > 25 mm Hg; pulmonary artery occlusion pressure [PAOP], < 16 mm Hg) was 23% (95% confidence interval, 19 to 27%). In bivariate analysis, higher mPAP was associated with lower FVC and FEV(1), higher Pco(2) and lower Po(2) in arterial blood, and more right heart dysfunction. Multivariate analysis demonstrated that higher mPAP was associated with shorter distance walked in 6 min, even after adjustment for age, gender, race, height, weight, FEV(1), and PAOP (-11 m for every 5 mm Hg rise in mPAP; 95% confidence interval, -21 to -0.7; p = 0.04).


CONCLUSIONS
Higher pulmonary artery pressures are associated with reduced exercise function in patients with severe COPD, even after controlling for demographics, anthropomorphics, severity of airflow obstruction, and PAOP. Whether treatments aimed at lowering pulmonary artery pressures may improve clinical outcomes in COPD, however, remains unknown.
Sims
Michael W
MW
Pulmonary, Allergy, and Critical Care Division, Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA; Airways Biology Initiative, Department of Medicine, and the Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA. Electronic address: michael.sims@uphs.upenn.edu.
Margolis
David J
DJ
Airways Biology Initiative, Department of Medicine, and the Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA.
Localio
A Russell
AR
Airways Biology Initiative, Department of Medicine, and the Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA.
Panettieri
Reynold A
RA
Pulmonary, Allergy, and Critical Care Division, Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA.
Kawut
Steven M
SM
Pulmonary, Allergy, and Critical Care Division, Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA; Airways Biology Initiative, Department of Medicine, and the Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA.
Christie
Jason D
JD
Pulmonary, Allergy, and Critical Care Division, Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA; Airways Biology Initiative, Department of Medicine, and the Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA.