Transcatheter aortic valve replacement for severe aortic regurgitation in quadricuspid aortic valve: a case report.

A 49-year-old woman with a congenital quadricuspid aortic valve presented in cardiogenic shock due to severe aortic regurgitation. She underwent transfemoral transcatheter aortic valve replacement with a 29 mm self-expanding prosthesis. The procedure was technically successful with minimal paravalvular leak and significant symptomatic improvement. However, her long-term course was complicated by medication nonadherence, valve thrombosis, thromboembolic coronary events, and progressive heart failure. This case highlights the anatomical and technical challenges of transcatheter valve therapy in non-tricuspid anatomy, including annular sizing and valve anchoring without calcification, and underscores the critical importance of post-procedural anticoagulation adherence and meticulous follow-up to prevent thrombotic complications.