2 Case Reports in Medicine Figure 1: Chest X-ray revealed enlargement of mediastinum. Figure 2: CT scan of the chest with an intimal ﬂap separating the true and false lumen, mural thrombus near the intimal ﬂap, aneurysm of the ascending thoracic aorta approximately 11 cm in diameter, and pleural eﬀusion at right hemithorax. hypertension, the Marfan syndrome, and previous cardiac surgical procedures (cannulation, cross clamp, AVR) are some of the risk factors [5, 6]. Giant pseudoaneurysm and dissection of the ascending aorta after AVR is uncommon. The incidence of acute dissection among patients with signiﬁcant aortic dilatation following AVR is 27%, whereas the overall incidence of acute aortic dissection after AVR is 0.6% [6, 7]. The interval between valve replacement and dissection may vary from 2 months to 17 years [1, 2, 7, 8]. The growth rate of the ascending aorta dilatation associated with aortic valve disease is thought to be diﬀerent from that of an aorta dilated spontaneously with a normal aortic valve [3, 7, 9]. The mechanism of pseudoaneurysm after aortic valve surgery is unclear; defect in the aortotomy suture lines, fragility of the aorta, extensive calciﬁcation in the aortic wall, iatrogenic trauma due to manipulation during AVR, infection, jet ﬂow that caused the poststenotic Figure 3: CT scan of the chest revealed pleural eﬀusion at right and left hemithorax and prosthetic aortic valve. ascending aortic dilatation similar to aortic wall disease in aortic stenosis and regurgitation are some of the possibilities [1–7, 10]. Ascending aortic pseudoaneurysms have high morbidity and mortality rates and result in death from dissection or rupture [2, 4, 9, 11]. Untreated acute-type dissection has a 40–60% mortality risk within 48 hours of the event (1% per hour), however, chronic aneurysms tend to become sym- ptomatic or rupture within 5 years [9, 11]. Thoracic aortic aneurysms tend to be asymptomatic, and nonlocalising sym- ptoms with widened mediastinum on the chest X ray may be some of the presentation forms [3, 4]. Therefore, periodical postoperative imaging after AVR, especially in patients with mildly or moderately dilated aortic root, increases the diagnosis of aortic aneurysms, which allowed elective treatment prior to the development of a complication [2– 11]. Dissections of ascending aorta are mostly (79%) charac- terized by retrosternal pain, while dissections of descending aorta are frequent (64%) together with interscapular as well as back pain [3, 12]. 47% of patient with type A dissections have back pain. Patients without anterior symptoms mostly have history of cardiovascular surgery, aortic aneurysm, or diabetes [3, 12–15]. Aortic dissection is frequently associated with hyperten- sion although hypertension is less commonly seen at initial presentation of ascending dissections. 64% of patients with type A aortic dissection do not have hypertension at the time of presentation. Pleural eﬀusion, widened mediastinum, advancing age (age > 70), type A dissection, and syncope are some of variables associated with hypotension [12, 15]. Pleural eﬀusion and enlarged diameter are signs for potential rupture [1–6]. Aortic regurgitation, aortic size, bicuspid aortic valve, fragility of the aortic wall, and systemic hypertension are some of the risk factors for late dissection of the ascending aorta while previous AVR is an independent predisposing