TOPIC: Transplantation TYPE: Fellow Case Reports INTRODUCTION: Lung transplantation is an effective option for those with advanced lung disease. Acute or chronic graft failure may lead to significant morbidity and mortality. Lung retransplantation is an alternative for patients that develop allograft dysfunction. Preoperative investigation must consider complications from previous cardiothoracic procedures that may impose additional risk. We herein reported on a previously undiagnosed pseudoaneurysm of the thoracic ascending aorta (PTA) successfully treated during a bilateral lung retransplantation. CASE PRESENTATION: Patient is a 24-year-old female with history of bilateral lung transplant due to cystic fibrosis with pulmonary manifestation. She was admitted for bilateral retransplantation after progressive decline in lung function. Initial decompensation consisted of acute respiratory failure with hypoxemia secondary to Pseudomonas pneumonia, consistent with A4 pulmonary allograft rejection. She rapidly progressed to other episodes of respiratory failure, infection, dyspnea on minimal exertion, rest tachycardia, and significant decline in spirometry consistent with Bronchiolitis Obliterans Syndrome. After general anesthesia, upon intraoperative Transesophageal echocardiography, the anesthesiologist detected a previously undiagnosed PTA on the anterior surface. A redo bilateral sequential lung transplantation with PTA repair was performed under cardiopulmonary bypass (CPB) with transverse sternotomy and cannulation of right common femoral artery and vein. With the heart decompressed, the PTA, which was 2x1.5x2cm and located at the previous cannulation site, was dissected from the surrounding adhesions. The PTA was resected and repaired by partial clamping of the aorta, followed by an uneventful bilateral lung transplant. Pathology reports of the resected PTA showed fibroadipose and benign thymic tissues. Cultures were negative. The patient had an uncomplicated post-operative course and was discharged after 19 days. DISCUSSION: This is the first report of PTA as a complication of lung transplant. Postoperative PTA is rare and has been described only in cardiac procedures. It usually occurs in previous suture lines and in immunocompromised patients such as transplant recipients it is commonly related to infection in these endothelial damaged sites. It is crucial to be aware that they can be asymptomatic or misdiagnosed due to the primary clinical conditions such as lung rejection or multiple infections in the present case. In hindsight, the PTA was present in the patient's previous chest CTs and would have been easily identified if the arterial phase was performed. CONCLUSIONS: It is imperative that the multidisciplinary team involved in the care of patients undergoing lung retransplantation is vigilant about the possibility of PTA. Preoperative diagnosis can be lifesaving by avoiding rupture and exsanguination in a new cardiothoracic procedure REFERENCE #1: Glanville AR, Verleden GM, Todd JL, Benden C, Calabrese F, Gottlieb J, Hachem RR, Levine D, Meloni F, Palmer SM, Roman A, Sato M, Singer LG, Tokman S, Verleden SE, von der Thüsen J, Vos R, Snell G. Chronic lung allograft dysfunction: Definition and update of restrictive allograft syndrome-A consensus report from the Pulmonary Council of the ISHLT. J Heart Lung Transplant. 2019 May;38(5):483-492. REFERENCE #2: Behzadnia N, Ahmadi ZH, Mandegar MH, Salehi F, Sharif-Kashani B, Pourabdollah M, Ansari-Aval Z, Kianfar AA, Mirhosseini SM, Eiji M. Asymptomatic mycotic aneurysm of ascending aorta after heart transplantation: a case report. Transplant Proc. 2015 Jan-Feb;47(1):213-6. REFERENCE #3: Sullivan KL, Steiner RM, Smullens SN, Griska L, Meister SG. Pseudoaneurysm of the ascending aorta following cardiac surgery. Chest. 1988 Jan;93(1):138-43. DISCLOSURES: No relevant relationships by Thais Peclat, source=Web Response No relevant relationships by Si Pham, source=Web Response No relevant relationships by Eduardo Rodrigues, source=Web Response