Update on pulmonary hypertension complicating chronic obstructive pulmonary disease

Pulmonary hypertension (PH) is the hemodynamic manifestation of various pathological processes that result in elevated pulmonary artery pressures (PAP). The National Institutes of Health Registry defined pulmonary arterial hypertension as the mean PAP of more than 25 mm Hg with a pulmonary capillary wedge pressure or left atrial pressure equal to or less than 15 mm Hg. This definition remains the currently accepted definition of PH that is used to define PH related to multiple clinical conditions including chronic obstructive pulmonary disease (COPD). The estimated US prevalence of COPD by the National Health Survey in 2002 in people aged >25 was 12.1 million. There is a lack of large population-based studies in COPD to document the correct prevalence of PH and outcome. The major cause of PH in COPD is hypoxemia leading to vascular remodeling. Echocardiogram is the initial screening tool of choice for PH. This simple noninvasive test can provide an estimate of right ventricular systolic and right atrial pressures. Right heart catheterization remains the gold standard to diagnose PH. It provides accurate measurement of mean PAP and pulmonary capillary wedge pressure. Oxygen therapy remains the cornerstone therapeutic for hypoxemia in COPD patients. Anecdotal reports suggest utility of PDE5-inhibitors and prostacyclin to treat COPD-related PH. Large randomized clinical trials are needed before the use of these drugs can be recommended.