Is surgical ligation of an accessory left superior vena cava always safe?

In patients considered for bidirectional Glenn or Fontan procedures, the association of left superior vena cava (LSVC) with ostial atresia of the coronary sinus should be diagnosed preoperatively in order to avoid surgical division or ligation of the LSVC and the negative effect of resulting coronary venous hypertension on myocardial perfusion. This report discusses the angiographic and hemodynamic features of LSVC when it is the only drainage route from a blind coronary sinus. A retrograde flow in the LSVC seen by Doppler ultrasonography should raise the suspicion of this diagnosis.