A 12-year-old boy with ventricular septal defect and patent ductus arteriosus was presented to the operating room. Upon clamping the patent ductus arteriosus, the femoral arterial pressure curve was lost; however, it returned upon unclamping. Upon further dissection, an interrupted aortic arch was found between the left subclavian artery and patent ductus arteriosus. The surgery was discontinued for further evaluation.