Abstract Introduction Staphylococcus aureus infective endocarditis (IE), particularly methicillin-resistant strains (MRSA), remains one of the most aggressive etiologies of bacterial endocarditis, often resulting in extensive valvular destruction and systemic embolization. Vegetations exceeding 2 cm are rare, yet vegetation size is a key prognostic factor, correlating with higher risks of embolic events, abscess formation, heart failure, and mortality. We present an unusual case of MRSA IE involving both the aortic and tricuspid valves, associated with a giant 7.0 cm vegetation arising from a perimembranous ventricular septal defect (VSD) and extending into the tricuspid annulus. Case Presentation A 31-year-old man with a known perimembranous VSD presented with altered mental status and urinary incontinence five days after a scooter accident. On admission, he was febrile and hypoxic but hemodynamically stable. Laboratory testing revealed leukocytosis and MRSA bacteremia. Echocardiography demonstrated severe aortic regurgitation due to aortic valve involvement, a small perimembranous VSD, and a large mobile vegetation measuring 4.5 cm extending into the tricuspid and pulmonic valves. CT imaging showed multiple embolic infarcts in the brain, spleen, and kidneys, as well as cavitary pulmonary lesions consistent with septic emboli. The patient underwent mechanical aortic valve replacement, tricuspid valve replacement with a tissue prosthesis, and VSD closure. Intraoperatively, a friable 7.0 cm vegetation was identified arising from the inferior VSD margin with a tricuspid annular abscess. He was treated with intravenous vancomycin, later transitioned to Telavancin due to resistance, completing a 42-day course. His postoperative course was stable, and follow-up echocardiography showed preserved cardiac function. Discussion Vegetations in IE typically measure less than 1-2 cm. Giant vegetations are rare and carry a high risk of embolization, abscess formation, and hemodynamic instability. MRSA IE can lead to massive, destructive vegetations involving multiple cardiac valves with systemic embolization. Thus, often necessitating early surgical intervention despite appropriate antimicrobial therapy. Early diagnosis, coordinated care, and timely surgical management are essential to prevent catastrophic complications and improve survival. This case underscores the importance of early recognition of MRSA bacteremia, rapid echocardiographic evaluation, and prompt multidisciplinary management. This abstract is funded by: None
Yepez et al. (Fri,) studied this question.