6 Committee comments
6.1 The Committee noted that most of the evidence on the use of valve-in-valve transcatheter aortic valve implantation (ViV‑TAVI) for patients with aortic bioprosthetic valve dysfunction was in older patients at high risk from surgery. It noted that there was no published evidence specific to patients judged to be at low risk from surgical aortic valve replacement, and it therefore considered that there is uncertainty about the balance of risks and benefits of ViV‑TAVI for these patients. This uncertainty underpinned the recommendation that the procedure should only be used in the context of research for patients who are at low risk from surgical aortic valve replacement (see section 1.3).
6.2 The Committee was advised to consider patients having ViV‑TAVI for rescue of suboptimal TAVI separately from those having the procedure for degenerated bioprosthetic valves, and the evidence for those 2 groups is presented separately. The Committee considered that the use of ViV‑TAVI for rescue of suboptimal TAVI is covered by the recommendations set out in sections 1.1 and 1.2 of the guidance.
6.3 The Committee noted that survival was lower among patients with small bioprostheses and those who, before the procedure, had predominant stenosis rather than regurgitation of their surgically implanted valves.