Congenital Absence of the Pulmonary Valve and Dysfunction of Fetal Duct – Source of Wide Spec-Trum of Cardiovascular Pathology

Abstract

Goal: Congenital absent pulmonary valve with dysfunction and/or atypical ductus Botalli dysfunction (APV/DBD) may cause a wide spectrum of heart anomalies. The goal of this study is to describe the clinical appearance, present prenatal (fetal) and postnatal diagnostic methods, course, and outcome of this rare entity which is often overlooked. Methods and results: We present four patients, all with the entity manifested as an absent (dysfunctional) pulmonary valve with various stenosis and insufficiency degrees and as a pathological enlargement of MPA and RPA dilatation, with consecutive pathological impression on large airways and consequently respiratory insufficiency with lethal outcome as a possibility. In at least three patients there was also atypical pathology of DB, and wide spectrum of pathologic changes in the right cavities of the heart: RV hypertrophy, RA enlargement, non-compaction cardiomyopathy and tricuspid insufficiency. In two patients the defect was diagnosed in utero. In these two patients we followed the guidelines suggested in recent literature: 1. prenatal diagnosis as an imperative, 2. early cardiosurgical correction with implantation of valved RV-PA conduit, 3. plication of pulmonary artery or LeCompte manoeuvre in order to relieve the bronchial compression. Two patients died because of right ventricular failure or respiratory insufficiency due to airway compression. Deletion syndrome (22q11.2 or 18q deletions), mentioned in etiopathogenic consideration as a part of the conotruncal anomalies spectrum, was not determined in any of the patients. Surviving patients remain under constant supervision of pediatric cardiologists. Conclusion: Congenital pulmonary valve dysfunction and/or atypical DB dysfunction in fetal period are a possible cause of dysplasia of pulmonary valve with consequent stenosis and insufficiency, as well as a spectrum of anomalies in right cardiac cavities and valves. Prerequisite for successful treatment is early (prenatal) diagnosis of the syndrome, early cardiosurgical intervention (ductus ligation and valved conduit RV-PA implantation), and plication of aneurismatic dilated pulmonary arteries with the aim to relieve the airways of their compression. The spectrum of changes is better recognised if one considers the theoretical assumption about a possible disorder of migration of neuroectoderm into the mesenchymal substructure of the heart, same as with other conotruncal anomalies.