Background: Systemic-to-pulmonary artery fistula has been identified as a very rare condition of which the clinical course cannot be fully predicted. Thus, the precise indication for treatment remains to be unclear.
Case Report: A 42-year-old man, without any history of congenital heart disease or chest wall injury, presented with a 3-day history of vague chest pain. As the initial examinations were found unremarkable, the patient underwent coronary CT angiography revealing a fistula between the left internal mammary artery (LIMA) and the upper lobe pulmonary artery. After confirming the fistula via selective LIMA angiography followed by coronary angiography revealing normal coronaries without fistulous connection, the fistula was closed using cyanoacrylate glue injection. Although a nontarget pulmonary embolization was observed to have occurred to a small extent, the complaint of the patient entirely disappeared following the procedure.
Conclusion: Considering the potential complications, it seems more favorable to close a systemic-to-pulmonary artery fis-tula. For a safe and effective treatment, the flow dynamics should be considered when choosing the method of embolization.