Transposition of the great vessels is incompatible with life unless there is also which associated defect?

Transposition of the great vessels is incompatible with life unless there is also which associated defect?

• A. There Is Also A Ventricular Septal Defect
• B. If The Foramen Ovale Closes At Birth
• C. If The Ductus Arteriosus Closes At Birth
• D. There Is Also A Pulmonary Stenosis

Answer: (A)

Transposition of the great vessels creates two parallel circuits, so survival depends on mixing between the systemic and pulmonary blood. A ventricular septal defect provides a direct pathway for mixing between the ventricles, allowing oxygenated blood from the left ventricle to reach the systemic circulation. This mixing is what keeps the neonate alive despite the abnormal great vessel connections. If mixing routes like the foramen ovale or the ductus arteriosus were to close, there would be little to no mixing and severe hypoxemia. Pulmonary stenosis can occur with transposition and may influence the balance of flows, but it does not universally provide the essential mixing that a ventricular septal defect does.

Transposition of the great vessels creates two parallel circuits, so survival depends on mixing between the systemic and pulmonary blood. A ventricular septal defect provides a direct pathway for mixing between the ventricles, allowing oxygenated blood from the left ventricle to reach the systemic circulation. This mixing is what keeps the neonate alive despite the abnormal great vessel connections. If mixing routes like the foramen ovale or the ductus arteriosus were to close, there would be little to no mixing and severe hypoxemia. Pulmonary stenosis can occur with transposition and may influence the balance of flows, but it does not universally provide the essential mixing that a ventricular septal defect does.