ABSTRACT
The respiratory system receives its blood supply from two distinct circulations, the bronchial and the pulmonary circulation. This circulation is at the origin of various pulmonary diseases. An overview of the normal pulmonary vascular physiology and the pathophysiology of common pulmonary vascular diseases such as pulmonary hypertension (PH), pulmonary embolism, pulmonary edema, and pulmonary arteriovenous malformations (PAVMs) are discussed in this chapter. The pulmonary circulation has many important secondary functions. The pulmonary circulation is a low-pressure system. Pulmonary arterial hypertension (PAH) is characterized by a progressive increase in resistance to blood flow engendered by the conjugated effects of vasoconstriction, pulmonary blood vessels remodeling, and in situ thrombosis. PH is a common complication of severe chronic respiratory diseases. In patients with PAH (group 1), the treatment will include general and supportive measures, such as diuretics and long-term oxygen therapy for hypoxemic patients.
