COronary Re-engageMent aFter randOm NavitoR alignmenT (COMFORT STUDY)

Transcatheter Aortic Valve Implantation (TAVI) is recommended by European and American guidelines to treat patients with aortic stenosis regardless of procedural risk (1, 2). In the last decades the increasing percentage of younger patients treated with TAVI, reflect the extensive indications in lower risk setting, highlighting the importance of easy coronary re-engagement after valve implantation. Considering the prevalence and the progression of a pre-existing coronary artery disease (CAD), the timing of coronary intervention should be accurate selected (3) addressing the percentage of unplanned percutaneous coronary intervention (PCI) after TAVI (4). In fact, while PCI before TAVR was previously recommend despite the uncertain prognostic role (5), recent data remarks the possibility of a postponed coronary intervention using a commissural alignment technique (6) that allows a predictable stent frame position in the sinus of Valsalva (7). Moreover, following the emerging concept of easy re-access, only a few types of prostheses have been shown to have an high degree of stent position predictability after implantation, leading to a limited option in terms of prosthesis choice. Furthermore, to achieve the best results with commissural alignment technique, accurate procedure planning and operator's expertise are required in order to properly manage the valve specific orientation in the aorta with consequent increase in time, radiation and procedure complexity.

However, geometry of the stent frame (height and size) and the anatomical characteristics of patients have to be enlisted as contributory factors to difficult coronary re-engagement and need to be evaluate in order to establish the feasibility of the re-access after TAVR.

The investigators' findings could provide data regarding the non-inferiority rate of coronary cannulation after a simpler procedure with Navitor implantation without alignment technique. Due to these results, the valves portfolio available in patients with coronary artery disease that needed PCI after TAVR, could be larger and various allowing the best protheses choice according to the patient's anatomy and operator's expertise. Finally, knowing the predictors of difficult re-engagement for both types of valves, regardless of implantation technique, could be interesting for an even more valve tailored approach.

The purpose of this study is to investigate the feasibility of coronary re-engagement after randomly (not aligned) Navitor implantation, as already perform in current clinical practice, due to a lower predictable orientation of this type of valve.