Aortic stenosis (AS) represents the most prevalent acquired valvular heart disease in European populations, and transcatheter aortic valve implantation (TAVI) has become the dominant treatment modality for patients with symptomatic severe AS. The latest 2025 ESC guidelines have broadened age-related eligibility, while the procedure still continues to be limited to centres with cardiac surgery on-site (CSOS). This limitation is in place, despite the very low rate of complications requiring emergent surgical conversion. This subsequently, may constrain procedural capacity and contribute to prolonged waiting times, which in turn are associated with increased pre-procedural mortality and heart failure-related hospitalizations. This prospective randomized open-label clinical trial aims to evaluate the safety and feasibility of performing TAVI in selected pilot centers operating without on-site cardiac surgery department (no-CSOS). Selected patients with severe native AS deemed suitable for transfemoral TAVI by a Heart Team will be enrolled. No-CSOS centers must meet predefined criteria, including operators experience, hybrid operating room availability, on-site vascular surgery availability, and established rapid transfer pathways to CSOS centers. The primary endpoint of the study is early 30-day safety based on VARC-3 criteria; secondary endpoints include additional composite outcomes. Patients will be randomly assigned in a 1:1 ratio using a central Web-based system to undergo TAVI either at a CSOS or non-CSOS site. A total of 404 patients (202 per group) is required. The study will inform national strategies and contribute to defining contemporary safety standards for TAVI delivery in no-CSOS centres.

The aim of this study is to assess whether TAVI performed in no-CSOS sites achieves clinical outcomes comparable to those achieved in established TAVI centers with surgical backup. Moreover, this study will contribute to updating safety standards for the treatment of aortic stenosis in the context of ongoing advancements in structural heart disease interventions and the increasing clinical demand for timely access to TAVI.

Although TAVI volume in Poland continues to rise - (n=4904 in 2024, increase by 21% compared with 2023) - the national rate of 127 procedures per million inhabitants remains below the European average. Very cautious epidemiological simulations published 8 years ago, in the setting of previous valvular guidelines, suggest that the estimated number of TAVI candidates in Poland is close to 11 000/per year. To that end, the requirement for on-site cardiac surgery substantially restricts access, with only 32 of more than 170 interventional cardiology centers in Poland currently offering TAVI. This limited availability contributes to prolonged waiting times for patients already qualified by the Heart Team, often exceeding six months, which is associated with a markedly increased risk of adverse outcomes related to aortic stenosis. With contemporary transcatheter heart valves offering an excellent safety profile, mortality among patients with AS is now higher during the waiting period for TAVI than after the procedure itself. This underscores the urgent need to expand access to this life-saving procedure by enabling no-CSOS centres to perform TAVI in appropriately selected settings.

Available large-scale registries and observational analyses consistently demonstrate that TAVI performed in no-CSOS centers can achieve clinical outcomes comparable to those of centers with surgical backup. These data indicate that, with appropriate patient selection and structured procedural safeguards, the absence of an on-site cardiac surgery does not adversely affect early or mid-term mortality or complication rates. The incidence of complications requiring emergent cardiac surgery is decreasing and well below 0.5%. However, when such events occur, they are associated with very high mortality (reaching up to 50%), which remains substantial regardless of surgical availability. The present study is unique in terms of conceptualization and methodology as unlike other currently being conducted, while providing maximum procedural safety, it does not limit the AS population to non-operable or highest-risk individuals, and therefore making the results potentially transferable to intermediate and low risk cohorts and subsequently making it more relevant in the light of recent valvular guidelines. Also, the exclusion of more complex aortic and access-site cases, or re-do interventions is in line with the already proven concept tested in coronary interventions field, where only the most complex anatomical cases are recommended to be performed at CSOS sites.

A multicenter Polish registry comparing balloon aortic valvuloplasty in stand-alone catheterization laboratories versus centers with on-site cardiac surgery provided important pilot data supporting the feasibility of interventional treatment for aortic stenosis in settings without surgical backup. Despite treating a higher-risk patient population, standalone laboratories demonstrated no significant differences in major adverse events compared with surgical centers. In-hospital mortality was similar - and even numerically lower in the stand-alone group (0.7% vs 2.9%, p=0.14) - while both settings achieved comparable hemodynamic improvement. Collectively, these findings underscore the safety and practicality of performing selected structural interventions without immediate on-site cardiac surgery.

In conclusion, current evidence indicates that, with adequate patient selection and well-defined procedural safeguards, the absence of on-site cardiac surgery does not preclude the safe and effective performance of TAVI. The findings of this study are expected to provide robust, nationally representative data to inform regulatory decisions and support the development of optimized care pathways that expand equitable access to TAVI.

Inclusion Criteria:

• Severe degenerative aortic valve stenosis with echocardiography derived criteria: mean gradient ≥40 mmHg or jet velocity ≥4.0 m/s or an aortic valve area (AVA) of ≤1 cm2 (or AVA index <0.6 cm2/m2)
• Symptomatic due to aortic valve stenosis as demonstrated by NYHA Functional Class ≥ II.
• Suitable for percutaneous transfemoral access
• Age ≥70 years

Exclusion Criteria:

• Prior aortic valve replacement
• Bicuspid aortic valve on pre-procedural CT
• Contraindication to femoral access
• Other imaging features indicating increased procedural risk (extremely horizontal aorta, severe aortic root dilatation, aortic annulus outside the range of commercially available devices, high coronary risk occlusion)
• Life expectancy <12 month or active malignancy
• Active endocarditis

upon reasonable request from third parties