Air embolism during unsuccessful transcatheter closure of secundum atrial septal defect in a patient with an undetected left-sided inferior vena cava

A 46-year-old man with a history of secundum atrial septal defect and interstitial lung disease was admitted to the hospital for a planned transcatheter closure of the atrial septal defect. Following multiple failed attempts to place a right femoral vein catheter, the procedure was aborted. Another attempt was made to the left femoral vein, but that attempt was complicated by an unfamiliar resistance. Even though resistance was met during insertion, the catheter was further inserted until a position in the inferior vena cava above the liver was obtained at fluoroscopy. Simultaneously, the patient became unresponsive. The procedure was immediately aborted and the atrial septal defect closure was not completed. Air embolism to the heart and brain was detected using echocardiography and computed tomography. The patient died 15 days after the procedure. Death was attributed to severe cerebral edema due to air embolism. The autopsy revealed a left-sided inferior vena cava. This case report demonstrates that unexpected congenital vascular anomalies complicating a routine transcatheter closure of the atrial septal defect can result in a fatal outcome.