Discussion
In more recent years, in UK there has been an increase in the use of the SC and axillary route, including percutaneous approaches performed under local anaesthetic, and a corresponding decline in TA access. SC and TA still remain the preferred alternative to the default femoral delivery, and they are fundamental in case of iliofemoral hostility, which may contraindicate its navigation. Despite the progressive reduction in the calibre of TAVI delivery systems, which are nowadays available on the market, in a significant proportion of patients, which range from 10 to 15%, small vessels, calcification, previous stenting deployment, tortuosity, and pathological stenosis may preclude a percutaneous femoral approach. Because patients who received a surgical alternative access commonly have a worse risk-profile, it could be useful to analyse which worse outcomes are related to the patient rather than to the procedure. There is a lack of data prospectively comparing outcomes and long-term survival after SC vs TA TAVI. In this regard, the UK TAVI national registry offer the opportunity to explore whether there was a difference in outcomes and survival between TA and SC and this is the reason because we decided to focus our analysis on this wide pool of data. Our study found that the SC approach was associated with increased short-term (12 months), but not long-term (up to 96 months) mortality. Compared to TA, the SC approach has the advantages of obviating separation of the pleura, and thus may reduce postoperative pain and respiratory complications that are commonly related to each thoracotomy. On the other hands, SC it can be restricted by anatomical features such as tortuosity or small vessel calibre. In case of pre-existing left internal mammary artery bypass graft SC may also expose patient to the risk of acute myocardial ischemia during navigation. Furthermore, the relative lack of a muscular component to the subclavian wall makes this artery more incline to iatrogenic dissection. This study collected, compared, and analysed surgical TAVI implantation in a large sample of patients in a national real-world setting. Considering that there is a paucity of data directly comparing outcomes for SC and TA TAVI approaches, in the absence of randomised controlled trial data, prospectively collected observational data offer the best alternative for such kind of comparison. We reported a large series of SC and TA cases over a long period and each limitation of no-randomized observational study was robustly corrected by an accurate and rigorous propensity score analysis. We aimed to describe and analyse the whole pool of data regarding the early and intermediate experience of an entire country (UK), and to clarify the outcomes associated with the main two different surgical choices, which are alternative to the femoral delivery. We found no difference in long-term mortality between SC and TA, and their respective Kaplan-Meier survival curves were almost overlapped. According to our analysis, SC had faster recovery process than TA, in fact the median in hospital length of stay was 2.8 days less than those with the TA approach. Conversely, the main downside of SC was the high rate of PPI, but this outcome is likely to be related to the use of Core Valve™ (Medtronic) for the SC approach. However, in our dataset, PPI after TAVI did not affect the overall long-term survival. As with any operative technique, the choice to select a specific approach is determined by different combinations of patients’ comorbidity, vascular anatomy/pathology, transcatheter heart valve type, availability of new performing devices on the market, and skill mixing along with the expertise and experience of the entire Heart Team, who remains the key factor to lead to the best choice tailored for each patient.