False aneurysm of the ascending aorta following aortic valve replacement

False aneurysm of the ascending aorta is a rare and lifethreatening complication of open heart surgery, usually occurring late after operation. Echocardiography, especially transesophageal echocardiography, is a non-invasive method of examination which can be very helpful in its diagnosis. Deep hypothermia and circulatory arrest allow a bloodless field during surgery and provide an adequate patient protection. Infection is a very well known predisposing factor, but cystic medial necrosis of the aortic wall also seems to play a role in this complication. We report three cases, two of them had cystic medial necrosis and the presence of infection could be proved in none.