Abstract: Objective To examine the correlation of the changes in the serum markers (C-reactive protein, endothelin-1,
interleukin-6, and brain natriuretic peptide) with chronic obstructive pulmonary disease (COPD) and pulmonary hypertension
secondary to COPD. Methods A total of 174 COPD patients with acute exacerbation, admitted between February 2011 and
February, 2013, were enrolled in this study, with 43 volunteers with normal pulmonary functions as controls. Pulmonary
arterial pressure was determined by Doppler echocardiograph, and the severities (mild, moderate and severe) of PH secondary
to COPD was evaluated. The levels of serum markers were determined using ELISA kits. Results The levels of serum markers
in patients with COPD was significantly elevated compared with those of the control subjects (P<0.05), and further increased in
patients with pulmonary hypertension secondary to COPD (P<0.05). A positive correlation was found between these serum
markers and pulmonary artery pressure in COPD patients with mild and moderate pulmonary hypertension. In patients with
severe pulmonary hypertension, only the serum level of brain natriuretic peptide continued to increase with pulmonary artery
pressure (P<0.05), and the other markers did not further increase. Conclusions Early and combined examination of these
serum markers in patients with COPD can help to identify pulmonary hypertension in early stage and estimate the severity of
pulmonary hypertension. Hemodynamic monitoring of the changes of these serum markers can be of important clinical value
in the treatment of pulmonary hypertension secondary to COPD and in evaluation of the prognosis of COPD.