Phan, T.N., Nguyen, T.H., Do, L.A. and Nguyen, C.H. 2026. Successful valve-in-valve transcatheter aortic valve implantation using a hydra transcatheter aortic valve in a patient with severe degeneration of a surgical bioprosthesis: a case report. The Vietnam Journal of Cardiovascular and Thoracic Surgery. 54, (Jan. 2026), 77 - 84. DOI:https://doi.org/10.47972/vjcts.v54i.1634.