A nineteen-month-old girl was taken up for patent ductus arteriosus (PDA) device closure. A diagnostic catheter from the right femoral venous access entered the superior vena cava (SVC), through the azygos vein suggesting interruption of inferior vena caval with azygos continuity. Therefore, the PDA device was closed from the right jugular venous access. However, a postprocedure echocardiogram (echo) showed a patent inferior vena caval connection into the right atrium. An angiogram from femoral veins showed communication between the iliac veins and the azygos system, in addition to normal drainage into the inferior vena cava (IVC). Congenital communication between the iliac veins and the azygos system can mimic IVC interruption. An attempt to theoretically explain the embryological origin of the communication has been made.