Transcatheter Aortic Valve Implantation for Pseudoaneurysm of the Mitral-Aortic Intervalvular Fibrosa Causing Severe Aortic Regurgitation.

Pseudoaneurysm of the mitral-aortic intervalvular fibrosa (P-MAIVF) is a rare complication following infective endocarditis or valve surgery. We report the case of a 65-year-old male who developed a P-MAIVF following surgical mitral valve replacement for infective endocarditis. Shortly after the surgery, although the patient remained afebrile and blood cultures were negative, routine transthoracic echocardiography revealed new-onset severe aortic regurgitation. Multimodality imaging confirmed a P-MAIVF extending into the non-coronary sinus and the left ventricular outflow tract, causing valvular incompetence despite a structurally normal aortic valve. Given the prohibitive surgical risk, an off-label transcatheter aortic valve implantation (TAVI) using a 34 mm self-expanding Evolut FX prosthesis was performed, aiming to exclude the pseudoaneurysm. Despite technical challenges related to the absence of annular calcification and catheter misplacement into the pseudoaneurysm, the prosthesis was successfully implanted with full exclusion of the pseudoaneurysm. At 3-month follow-up, the patient remained asymptomatic, with no residual aortic regurgitation and complete exclusion of the P-MAIVF on CTA. To our knowledge, this is the first reported case of a native, non-calcified aortic root pseudoaneurysm causing severe aortic regurgitation successfully treated with off-label TAVI. Multimodal imaging and careful preprocedural planning were key to procedural success.