Persistent left superior vena cava identified by transesophageal echocardiography.

A 70-year-old female with severe aortic stenosis presented for aortic valve replacement and underwent routine preoperative Swan-Ganz catheter placement. Transesophageal echocardiography demonstrated a dilated coronary sinus with a catheter present. A high suspicion of venous anomaly prompted an agitated saline study. Flow through the coronary sinus into the right atrium was observed, confirming the presence of a persistent left superior vena cava. Although the persistent left superior vena cava has a low prevalence in the general population, it is one of the most common thoracic venous anomalies. During central venous cannulation, the presence of venous anomalies increases procedural complication rates. Fortunately, our patient remained asymptomatic both before and after catheter insertion. Awareness of this anomaly could help clinicians avoid complications.