Chronic obstructive pulmonary disease (COPD) is most commonly caused by smoking.
Smoking causes inflammation and injury to the blood vessels in the lungs. This injury decreases the ability of the blood vessels to deliver enough oxygen to the rest of the body.
In patients who have COPD, pulmonary hypertension, or high blood pressure, can develop in the lungs because of this inflammation.
In these patients, airflow is decreased when they breathe in and out, which leads to shortness of breath, especially during exercise.
This decreased airflow also requires the right side of the heart to work harder to pump blood through narrowed arteries in the lungs, as in other patients who have pulmonary hypertension.
Although some treatments are available for COPD, none are approved for COPD associated with pulmonary hypertension, and oxygen therapy is usually required.