Ductus aeriosus dependent blood flow is mandatory in all of the following congenital hea diseases EXCEPT:: (A) Truncus aeriosus, (B) Hypoplastic left hea syndrome, (C) TGA with Intact ventricular septum, (D) Obliterated aoic arch
Answer is A. - In Truncus aeriosus, both the aoa and pulmonary aery arise from a common large blood vessel. - So there is already complete mixing of systemic and pulmonary circulations; fuher mixing is not necessary. Hence it is ductus independent. - In all other given options, mixing of pulmonary systemic circulations is necessary to maintain relatively better oxygenation. Thus, dependent on ductus