Valve-in-Valve TAVR in Surgical Stentless Aortic Bioprostheses, a Challenging Scenario

Background and objectives: Valve-in-valve transcatheter aortic valve replacement (ViV TAVR) has become an established treatment for failed surgical bioprostheses in patients at high surgical risk. However, procedures performed in degenerated stentless aortic valves remain particularly challenging because of the absence of a radiopaque frame, variable surgical implantation techniques, and a potentially increased risk of coronary obstruction. Evidence in this specific setting is limited. We conducted a systematic review of the literature to identify studies reporting ViV TAVI in degenerated stentless surgical bioprostheses. Materials and methods: Case reports and case series were included when patient-level or clearly identifiable data were available. Baseline characteristics, anatomical features, procedural strategies, and clinical outcomes were extracted and analyzed using a descriptive approach. A total of 54 studies were included, encompassing 294 ViV TAVI procedures performed in failed stentless aortic valves. Results: The mean patient age was 73.9 years, and the average STS-PROM score was 13.45%, reflecting a high-risk population. The most frequently treated prosthesis was the Medtronic Freestyle valve, and the predominant mechanism of failure was regurgitation. Transfemoral access represented the most common approach, while balloon-expandable and self-expanding transcatheter valves were used with similar frequency. Coronary protection strategies were adopted in a minority of procedures, whereas adjunctive procedural techniques such as pre- or post-dilation were relatively common. Device-related complications were mainly driven by coronary obstruction, while cardiac complications included myocardial infarction and unplanned coronary intervention. Overall, VARC-3 device success was achieved in the majority of procedures, with acceptable short-term mortality despite the complexity of the treated population. Conclusions: ViV TAVR in degenerated stentless bioprostheses appears feasible and generally effective but remains associated with specific procedural challenges, particularly related to coronary obstruction risk. Careful anatomical assessment and tailored procedural planning are essential, and larger contemporary studies are needed to better define optimal management strategies in this complex setting.