Introduction
The transfemoral (TF) approach is the established default vascular access for transcatheter aortic valve implantation (TAVI)1,2. However, small vessel calibre and/or peripheral vascular disease (calcification, previous stenting deployment, tortuosity, pathological stenosis) may preclude femoral TAVI in a significant number of patients3. Despite the miniaturization of transcatheter aortic valve delivery systems, it is estimated that 10% to 15% of patients will still have unsuitable ileo-femoral arteries for TAVI4. Alternative approaches are transapical (TA), direct aortic (DA), subclavian/axillary (SC), carotid, and transcaval approach5. In the timeline, the TA access was the first one alternative which was developed, but it had high rate of bleeding and mortality compared to TF6, so in 2008 was described the first SC implantation route for transcatheter aortic valve, which was aiming to address the TA downsides7. Currently, the TA TAVI is performed less frequently in the United Kingdom (UK)8. Consequently, the SC/axillary is becoming the predominant alternative access approach9. Because trials data recommend TAVI for high-, intermediate-, and even low-risk operable patients10 and because there is a lack of data prospectively comparing outcomes after SC vs TA TAVI, it is useful to analyse the UK TAVI registry to determine whether there was a difference in procedural- related complications according to Valve Academic Research Consortium-2 (VARC-2) criteria, and in short-, medium-, and long-term survival between these main two alternative vascular approaches, which are fundamental in case of femoral contraindication for TAVI delivery. In this regard, the aim of this study was to compare complications and morbidity/mortality associated with TA and SC, which are the main choice for TAVI when TF is precluded in a real-world long-time national data setting.