Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 48 3 2010 06 15 204 206 EN Seyed Khalil Forouzannia Cardiovascular Research Center, Afshar Hospital, Shahid Sadooghi University of Medical Sciences, Yazd, Iran. Mohammad Hasan Abdollahi Cardiovascular Research Center, Afshar Hospital, Shahid Sadooghi University of Medical Sciences, Yazd, Iran. Seyed Jalid Mirhosseini Cardiovascular Research Center, Afshar Hospital, Shahid Sadooghi University of Medical Sciences, Yazd, Iran. Seyed Hossein Moshtaghion Cardiovascular Research Center, Afshar Hospital, Shahid Sadooghi University of Medical Sciences, Yazd, Iran. Habibollah Hosseini Cardiovascular Research Center, Afshar Hospital, Shahid Sadooghi University of Medical Sciences, Yazd, Iran. Mohammad Hossein Mirshamsi Cardiovascular Research Center, Afshar Hospital, Shahid Sadooghi University of Medical Sciences, Yazd, Iran. 2015 09 28 Mycotic pseudoaneurysm of the ascending aorta is rare in patients undergoing coronary artery bypass graft (CABG) and usually caused by staphylococcus aureus. We describe a patient with a mycotic pseudoaneurysm of the ascending aorta at the proximal vein graft anastomosis site after CABG. Culture from the sinus tract of the sternum and from the aneurysm sac was Klebsiella pneumoniae. Surgical technique was patch repair of aorta under hypothermic circulatory arrest. He is asymptomatic at 24 months follow-up. https://acta.tums.ac.ir/index.php/acta/article/view/3679 https://acta.tums.ac.ir/index.php/acta/article/download/3679/3654