Pulmonary hypertension in COPD

Pulmonary hypertension (PH) commonly complicates COPD, with an estimated prevalence of 20-63%. Most PH in COPD is mild-to-moderate in severity, although a small proportion of patients develop PH "out of proportion" to their degree of airflow obstruction. The development of PH is associated with worsened functional status and decreased survival. The pathogenesis of COPD-associated PH is incompletely understood but is believed to result from a complex interplay of inflammation, endothelial dysfunction and vascular remodelling due to hypoxia and cigarette smoke, mechanical factors resulting from air-trapping, and host genetic factors. Physical examination, ECG and radiographic findings may be suggestive of PH but are nonspecific. Echocardiography is useful as a screening tool for PH but may over-or underestimate pulmonary pressures. Right heart catheterisation remains the gold standard for diagnosis. Treatment is focused on smoking cessation, optimal therapy of COPD and supplemental oxygen. There is interest in vasodilator therapy for COPD-associated PH, particularly for those with out-of-roportion PH; however, this approach requires further evaluation in clinical trials.