Pulmonary artery catheterization is used to evaluate primary pulmonary hypertension. In the procedure, a thin, flexible tube called a Swan-Ganz catheter is usually inserted in one of the veins in the neck and threaded into the right ventricle and pulmonary artery. This is a common way to measure the pressure in the pulmonary artery and find out what treatment is appropriate. It's also used in critically ill patients to provide continuous monitoring of heart function. It is sometimes called Swan-Ganz catheterization.