Pulmonary valve agenesis

Pulmonary valve agenesis (also known as absent pulmonary valve syndrome) is a rare congenital heart defect characterized by the complete or near-complete absence of the pulmonary valve leaflets. In most cases, this condition occurs in association with tetralogy of Fallot (known as tetralogy of Fallot with absent pulmonary valve), though it can rarely occur as an isolated finding. The absent or rudimentary valve leaflets result in both pulmonary stenosis (due to a dysplastic valve annulus) and severe pulmonary regurgitation (free backflow of blood from the pulmonary arteries into the right ventricle). A hallmark feature of this condition is massive aneurysmal dilation of the main and branch pulmonary arteries, which can compress the tracheobronchial tree and lead to significant airway obstruction. Key symptoms include respiratory distress, wheezing, recurrent respiratory infections, and cyanosis, which are often present from birth or early infancy. The airway compression caused by the dilated pulmonary arteries can be life-threatening, particularly in neonates and young infants, and is the primary determinant of clinical severity and prognosis. Cardiac symptoms include signs of right heart volume overload and, when associated with tetralogy of Fallot, a ventricular septal defect and right ventricular outflow tract obstruction. Some patients may also have an associated deletion of chromosome 22q11.2 (DiGeorge/velocardiofacial syndrome). Treatment is primarily surgical and typically involves open-heart surgery to close the ventricular septal defect (if present), relieve right ventricular outflow tract obstruction, insert a competent pulmonary valve (using a homograft or bioprosthetic valve), and reduce the size of the dilated pulmonary arteries (pulmonary arterioplasty) to relieve airway compression. The timing and approach to surgery depend on the severity of respiratory compromise. Outcomes have improved with advances in surgical techniques and perioperative care, though patients with severe neonatal airway obstruction continue to have a guarded prognosis. Long-term follow-up is essential, as re-intervention for pulmonary valve replacement or residual airway issues may be needed.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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