Absent pulmonary valve is a rare defect in which the pulmonary valve is either missing or poorly formed. The pulmonary valve allows oxygen-poor blood to travel from the heart to the lungs. When the pulmonary valve is missing, the branch pulmonary arteries are very enlarged and press down on the airways in the lung, causing breathing problems.
Review Date 2/23/2022
Updated by: Thomas S. Metkus, MD, Assistant Professor of Medicine and Surgery, Johns Hopkins University School of Medicine, Baltimore, MD. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.