Rapid progression of mitral-aortic intervalvular fibrosa pseudoaneurysm in a patient with bicuspid aortic valve endocarditis: a case report and comprehensive literature review

Pseudoaneurysm of the mitral-aortic intervalvular fibrosa (PMAIVF) is a rare, life-threatening complication typically associated with infective endocarditis (IE) and prior cardiac surgery. Here, we report an unusual case of a 28-year-old woman with a congenital bicuspid aortic valve (BAV) who experienced an exceptionally rapid progression to PMAIVF within just two months of IE onset. While transthoracic echocardiography (TTE) showed ambiguous perivalvular abnormalities, transesophageal echocardiography (TEE) clearly delineated the pseudoaneurysm, demonstrating its dynamic systolic expansion and diastolic collapse, as well as its communication with the left ventricular outflow tract. To better understand the clinical profile of this rare entity, we comprehensively reviewed 64 cases from 32 core literatures. The review confirms that PMAIVF predominantly affects young adults (median age 35 years) and is strongly driven by the coexistence of BAV and IE (accounting for ~ 85% of cases). This case and our literature review underscore the diagnostic limitations of TTE and highlight the indispensability of TEE for early identification, accurate anatomical mapping, and prompt surgical intervention (such as aortic valve replacement and patch repair) to prevent fatal complications like cardiac tamponade.