Difficult pulmonary artery catheterization in a patient with persistent left superior vena cava.

A persistent left superior vena cava is an uncommon congenital abnormality. It arises when the left anterior cardinal vein fails to regress during the embryonic period. Although such patients are usually asymptomatic, they may have associated cardiovascular abnormalities. The anaesthetist may encounter difficulty in the insertion of pulmonary artery catheters. Other implications in the management of these patients in the operating theatre or intensive care unit are discussed.