Minimally invasive coil embolization for significant left-to-right shunts due to giant coronary-to-pulmonary artery fistulas: a case report.

Background: Coronary-to-pulmonary artery fistula (CPF) is a rare disease, and its optimal treatment strategy remains controversial. Herein, we report a rare case of minimally invasive coil embolization of giant CPFs. Case summary: A 78-year-old man with a history of persistent atrial fibrillation and lumbar canal stenosis presented to our hospital with breathlessness. Cardiac computed tomography revealed giant CPFs inducing a significant left-to-right shunt (Qp/Qs 1/2.1) with a coronary artery aneurysm smaller than the size indicated for surgical treatment. To reduce the left-to-right shunt flow, coil embolization procedures for the fistulas were performed twice. Initially, the fistula arising from the right coronary artery was embolized using three Target® XXL (6 × 40 mm, 5 × 20 mm) and two Target® XL SOFT (4 × 12 mm) coils (Stryker Inc., Tokyo, Japan). One month later, the fistulas arising separately from the left coronary artery were embolized. After the procedures, the major shunt flow disappeared angiographically, and Qp/Qs significantly decreased to 1/1.2. Additionally, the fractional flow reserve of the left coronary artery increased from 0.79 to 0.93, and cardiopulmonary exercise testing showed an improvement in his exercise tolerance. Discussion: In similar cases, a surgical procedure with ligation of the CPFs combined with resection of a small aneurysm and coronary artery bypass grafting would normally have been considered the best approach. However, endovascular treatment targeting only the fistulas was a superior strategy considering the patient's age. The coil embolization technique effectively controlled the shunt flow of the CPFs. This technique is considerably less invasive than surgical therapy.