Valve-in-valve transcatheter aortic valve replacement for bioprosthetic valve failure complicated by hypo-attenuated leaflet thickening: a case report

Background: Bioprosthetic valve dysfunction (BVD) is a common complication after aortic valve replacement. Valve-in-valve transcatheter aortic valve replacement (ViV-TAVR) offers a less invasive alternative to redo surgery. However, research on hypo-attenuated leaflet thickening (HALT) following ViV-TAVR remains limited. Case summary: A 74-year-old man with hypertension, transient ischaemic attack, and prior aortic and mitral bioprosthetic valve replacements for infective endocarditis 10 years ago demonstrated elevated transaortic pressure gradients and severely reduced effective orifice area index without paravalvular leakage on transthoracic echocardiography (TTE) despite initial asymptomatic status. Serial TTE monitoring every 6 months initially suggested patient-prosthesis mismatch, later progressing to structural valve degeneration. However, transoesophageal echocardiography revealed no evident leaflet thickening or limited aortic valve opening. Furthermore, computed tomography (CT) confirmed proper aortic valve opening and further excluded pannus and thrombus. Due to symptom progression, worsening echocardiographic haemodynamics, and elevated NT-proBNP, ViV-TAVR with pre-procedural balloon valve fracture was performed, resulting in improved haemodynamics at 1-month follow-up. Post-procedural follow-up CT at 5 months revealed HALT, accompanied by only a mild elevation in peak aortic flow velocity on transthoracic echocardiography. Warfarin at a dose of 1 mg daily was initiated, resulting in thrombus resolution on 6-month follow-up CT, after which therapy was continued with regular TTE monitoring. Discussion: This case highlights the importance of multimodality and serial imaging in diagnosing and managing complex BVD. The observed HALT resolution raises questions about anticoagulation strategies after ViV-TAVR, especially in the absence of definitive guidelines.