A 60-year-old man experienced catastrophic haemodynamic decompensation 3 days following coronary artery bypass grafting (CABG). Aspiration thrombectomy to remove a left main coronary artery saddle embolus resulted in immediate haemodynamic improvement with no requirement for angioplasty or repeat bypass grafting. Coronary thromboembolism should be considered in the differential diagnosis of haemodynamic collapse post CABG. Urgent coronary angiography and aspiration thrombectomy may result in significant improvement for this condition.