Right-to-Left Anatomic Shunt Associated With a Persistent Left Superior Vena Cava: The Importance of Injection Site in Demonstrating the Shunt

摘要

Anatomic right-to-left shunt causes hypoxemia thatncan pose a diagnostic challenge to clinicians. Amongnthe many possible causes of right-to-left shunt, per-nsistent left-sided superior vena cava (PLSVC) with ann“unroofed” coronary sinus represents an uncommonncongenital anomaly in which detection by saline-ncontrast echocardiogram (bubble echo) or contrast-nenhanced CT scan requires injection of contrast innthe left arm. We present the case of an elderly mannwith hypoxemia on the basis of a right-to-left shuntnaccompanying a PLSVC with unroofed coronary si-nnus in whom the shunt escaped initial detectionnfollowing a bubble echo with contrast injected intonthe right arm. This case reminds pulmonary clini-ncians, who are frequently called on to assess thencause of hypoxemia, that specifying a contrast injec-ntion into the left arm is required in the pursuit of thisnspecific shunt-producing anomaly.