Mitral Valve Aneurysm With Perforation Resulting in Severe Mitral Regurgitation Secondary to Infective Endocarditis: A Report of a Rare Case

Mitral valve aneurysm (MVA) is a localised bulge of the mitral leaflet. Weakening of the mitral leaflet may be induced by infective endocarditis (IE), rheumatic disease, and connective tissue disorders like osteogenesis imperfecta, Marfan syndrome, and pseudoxanthoma elasticum. Complications of MVA include expansion, perforation, and regurgitation. IE, characterised by inflammation of endocardium, has significant morbidity and mortality. We report a case of mitral valve aneurysm with perforation in the setting of IE, diagnosed by transesophageal echocardiography (TEE). A 72-year-old male with multiple comorbidities presented with fluid overload and renal dysfunction. He had been previously admitted for sepsis, wet gangrene, and atrial fibrillation, which were treated medically. Blood cultures at the time grew <i>Staphylococcus aureus</i>. Upon investigating, a transthoracic echocardiogram (TTE) revealed multiple echogenic structures attached to the posterior mitral valve leaflet, likely consistent with vegetations. TEE revealed a calcified posterior mitral valve leaflet (PMVL) with an aneurysm along with perforation, resulting in severe mitral regurgitation, secondary to IE. Following multidisciplinary team (MDT) discussion, the patient was treated with antibiotics (intravenous followed by oral) due to multiple comorbidities with intravenous flucloxacillin for six weeks, followed by oral antibiotics, under the supervision of the outpatient parenteral antimicrobial therapy team. The patient completed the course with regular review by district nurses and the IE MDT, and remained clinically stable with no recurrence of bacteremia. TEE is considered superior to TTE in delineating the diagnosis of mitral valve perforation, as the former allows clear visualisation of complex mitral valve lesions. Prompt recognition and timely management are crucial in the prevention of mortality in patients with IE leading to perforation.