Pulmonary Hypertension Associated with Chronic Obstructive Pulmonary Diseases

Chronic obstructive lung diseases and so-called cor pulmonale have traditionally been connected by the link of pulmonary hypertension (PH). The concept that right ventricular hypertrophy is attributed to the afterload of the right ventricle, i.e., attributable to PH, has not been challenged and clinicians continue to attempt to explain cor pulmonale as a consequence of chronic PH. Both pulmonary parenchyma disease and primary vascular disease can lead to cor pulmonale. Among the obstructive lung diseases, chronic obstructive pulmonary disease (COPD)/emphysema has been recognized as the most common cause of PH in countries where smoking, but not schistosomiasis, is endemic. Until recently, clinical investigators conceptually associated PH in the setting of COPD/emphysema with chronic hypoxia. Pulmonary angiograms documented the extent of vascular involvement and vascular loss in patients with emphysema. Chronic oxygen supplemen­tation therapy was introduced into clinical management of COPD patients on the basis of the finding that oxygen treatment increased survival and that improved survival was associated with a small reduction in mean pulmonary artery pressure at rest. This chapter discusses the pathogenic mechanisms, diagnostic and therapeutic approaches for pulmonary hypertension associated with chronic obstructive pulmonary diseases.