A rare case of successful staged surgery for giant coronary artery aneurysm, multiple artery aneurysms, and coronary-to-pulmonary artery fistula.

Large coronary artery aneurysms (CAAs) with multiple arterial involvements are rare, and complications like coronary artery fistulae are extremely uncommon. Managing such cases presents a significant challenge. A 75-year-old female presented with a left inguinal mass and palpitations. Computed tomography revealed an abdominal aortic aneurysm and a left common iliac artery aneurysm. Coronary angiography identified a giant CAA and a coronary-to-pulmonary artery fistula. She underwent a two-stage surgical approach: first, an aortobiiliac Y-graft interposition, followed by open-heart surgery for aneurysmectomy and ligation of the pulmonary artery fistula 4 months later. Her postoperative course was uneventful, and she remained well at the 1-year follow-up. This case shows that prioritizing the aneurysm with the highest rupture risk, followed by staged treatment of CAAs, can lead to successful outcomes without major complications.