B51-26 Resection and Reconstruction of Intraseptal Aortic Root Mycotic Pseudoaneurysm in a Patient With Suspected Prosthetic Valve Endocarditis and Complete Heart Block

Abstract Introduction Intraseptal abscesses and destructive aortic lesions are rare complications of infective endocarditis, associated with increased morbidity and mortality. Case Description We present the case of an 80-year-old female with a remote history of mechanical aortic valve replacement who presented with recurrent falls and night sweats. On further evaluation, she was found to have complete heart block and Staphylococcus epidermidis bacteremia. Transthoracic echocardiography and computed tomography with angiography (CTA) of chest identified a 4 cm aortic root pseudoaneurysm versus abscess (Figure 1b). The patient underwent a re-do sternotomy, which revealed a large 6 x 6 cm thrombosed aortic root pseudoaneurysm with a 1 cm neck at the aortic root. The pseudoaneurysm extended into the interatrial septum and protruded into the right atrium with significant obliteration of the right atrial cavity. The thrombosed pseudoaneurysm was resected, and repair was performed using a pericardial patch repair of the residual atrial septal defect and a Hemashield patch reconstruction for the aortic root pseudoaneurysm excision site reconstruction (Figure 1a). An epicardial pacemaker was also implanted. Pathology confirmed thrombosed pseudoaneurysm. Postoperatively, the patient recovered without complication. She completed a six-week course of antibiotics with negative blood cultures. At two-month follow-up, transthoracic echocardiography showed no evidence of recurrent aneurysm. Discussion Infective endocarditis carries a moderate risk of progression to myocardial abscess formation. The proximity of the intraventricular and interatrial septa to the cardiac valves renders them particularly vulnerable to the spread of infection. Such cases usually require prolonged ventilation and increased intensive care unit length of stay. This case highlights the presentation and management of a rare yet severe complication-intraseptal extension of aortic root mycotic pseudoaneurysm-in the setting of prosthetic valve. It calls attention to the importance of maintaining a high index of suspicion and prompt management in patients presenting with non-specific symptoms suggestive of infective endocarditis. This abstract is funded by: No Funding