Pulmonary hypertension secondary to chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is the most common cause of secondary pulmonary hypertension (PH). PH secondary to COPD is associated with a worse prognosis of the disease, a low quality of life, as well as with a higher exacerbation frequency, and consequently with an increase in the healthcare cost of COPD patients. Prevalence of PH in COPD patients is currently unknown. The most important mechanisms leading to PH are hypoxic vasoconstriction, pulmonary hyperinflation and endothelial dysfunction. PH should be suspected in COPD patients in the presence of severe dyspnoea, disproportionate from the decline in lung function, or of severe hypoxemia. Exercise induced PH is an independent predictor of the development of resting PH in patients with COPD. Echocardiography is the first screening method for PH in patients with COPD and it should be widely used, as it can also appreciate the cardiac consequences of PH, especially on the right ventricle. Given the high negative predictive value of the echocardiographic estimation of systolic pulmonary arterial pressure (sPAP) in the diagnosis of PH, the absence of a high sPAP excludes important PH and further unnecessary invasive evaluation. Right cardiac catheterization remains the "gold standard" method in assessing PH, but it is less accessible and cannot be used in routine evaluation of patients with COPD. PH secondary to COPD is usually mild, but a small proportion of patients have severe PH, with specific characteristics, worse prognosis and a specific therapeutic approach.