Late saphenous vein graft rupture presenting as a compressive mediastinal pseudoaneurysm.

Late saphenous vein graft (SVG) pseudoaneurysm is a rare but life-threatening complication of coronary artery bypass graft surgery. An 80-year-old man presented with dyspnea and chest pain two decades after CABG (LIMA-LAD, SVG-RCA). Coronary angiography revealed SVG occlusion with contrast extravasation and mass formation adjacent to the right heart chambers. CT angiography confirmed a 39 mm mediastinal pseudoaneurysm from proximal SVG rupture, compressing the right heart chambers and lung, with consequent left ventricular dysfunction (EF 45%), elevated pulmonary pressures, and orthostatic hypotension. Following Heart Team discussion, the patient underwent successful pseudoaneurysm resection with right coronary artery revascularization using a left radial artery graft. Symptoms and cardiac function improved at one-month follow-up. This case highlights the importance of clinical suspicion for SVG pseudoaneurysm in patients with prior CABG, and the central role of CT angiography and multidisciplinary decision-making in management.