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Accessory valve cusp as a cause of outflow tract obstruction in atrio-ventricular and ventriculo-arterial discordance
K F Lindenau1, D Olthoff, K Bock
1Leipzig Heart Center, Karl-Marx University of Leipzig, GDR.
Insights
Congenital corrected transposition of the great arteries can present rare surgical challenges. This case highlights an accessory valve cusp causing left-ventricular outflow tract obstruction, misdiagnosed as pulmonary stenosis.
Area of Science:
- Cardiology
- Pediatric Cardiology
- Congenital Heart Disease
Background:
- Congenital corrected transposition of the great arteries (ccTGA) involves complex cardiac anomalies.
- Surgical correction of ccTGA presents significant challenges due to associated defects.
- Left-ventricular outflow tract obstruction is a critical consideration in pediatric cardiac surgery.
Observation:
- An 8-year-old boy with ccTGA was preoperatively diagnosed with valvular pulmonary stenosis.
- Intraoperative findings revealed a normal pulmonary valve without stenosis.
- Dystopic valvular tissue, a monocuspid atrioventricular valve, was identified below the pulmonary valve in the morphological left ventricle.
Findings:
- The accessory valve cusp, attached to an accessory papillary muscle, caused hemodynamically significant subvalvular pulmonary stenosis.
- This abnormal valve cusp was distinct from the mitral valve.
- Resection of the accessory valve cusp resolved the obstruction without damaging normal cardiac structures.
Implications:
- This case underscores the potential for accessory valve cusps to cause left-ventricular outflow tract obstruction.
- Accurate preoperative diagnosis is crucial, as rare anomalies can mimic common conditions.
- Recognition of such accessory valvular tissue is vital for successful surgical management in complex congenital heart disease.
Abstract:
Congenital corrected transposition of the great arteries in which there is both an atrio-ventricular and a ventriculo-arterial discordance has surgical significance only in consequence of the associated cardiac anomalies. Their surgical correction is subject to multifarious problems. An exceedingly rare cause of a left-ventricular outflow tract obstruction erroneously interpreted preoperatively in an eight-year-old boy is reported. In an l-transposition with inversion of both ventricles, the diagnosis "valvular pulmonary stenosis" was made preoperatively. However, a normally arranged tricuspid pulmonary valve without stenosis was revealed intraoperatively. On the other hand, dystopic valvular tissue in the form of a monocuspid atrioventricular valve which was attached to an accessory papillary muscle with several tiny tendons was found below the pulmonary valve in the morphological left ventricle. The accessory valve cusp, which was the cause of the hemodynamically relevant subvalvular pulmonary stenosis, had no connection with the mitral valve. The abnormal valve cusp was resected without injuring the normal structures. The angiographic follow-up after one year no longer revealed any pressure gradient. This case report points out the possibility of an outflow tract obstruction caused by a complete accesory valve cusp.