Pulmonary artery catheterization is a medical procedure used to measure pressures in the heart and lungs. A thin, flexible tube called a catheter is inserted through a vein, usually in the neck or groin, and guided into the pulmonary artery. This allows doctors to assess heart function and blood flow, helping diagnose conditions like heart failure or pulmonary hypertension. The procedure is typically performed in a hospital setting and may require local anesthesia. It provides valuable information about the heart's performance and can guide treatment decisions. Risks include infection, bleeding, and damage to blood vessels, but serious complications are rare.