Coronary Access After Evolut FX Plus TAVI: Impact of Commissural Alignment and the Large-Cell Frame Design: ACCESS-FX+ Registry

Coronary Access After Evolut FX Plus TAVI: Impact of Commissural Alignment and the Large-Cell Frame Design: ACCESS-FX+ Registry

The ACCESS-FX+ Registry is a prospective, multicenter, single-arm study designed to evaluate the feasibility of coronary access after transcatheter aortic valve implantation (TAVI) using the Evolut FX Plus transcatheter heart valve in patients with severe aortic stenosis.

TAVI has become an established treatment for patients with severe aortic stenosis across a broad range of surgical risk profiles. As TAVI is increasingly performed in younger patients with longer life expectancy, maintaining access to the coronary arteries after transcatheter heart valve implantation has become an important clinical consideration. A substantial proportion of patients undergoing TAVI have concomitant coronary artery disease and may subsequently require coronary angiography or percutaneous coronary intervention. However, coronary access after TAVI may be challenging because of the spatial relationship between the transcatheter heart valve frame, commissural posts, valve leaflets, and coronary ostia.

Commissural alignment between the native aortic valve and the implanted transcatheter heart valve may play an important role in preserving coronary access. Commissural misalignment may result in a commissural post or valve leaflet being positioned in front of a coronary ostium, potentially interfering with subsequent selective coronary cannulation. In addition to commissural alignment, the geometry and orientation of the transcatheter valve frame relative to the coronary ostia may influence the feasibility of coronary re-access.

The Evolut FX Plus transcatheter heart valve incorporates three enlarged frame cells designed to facilitate coronary access. This modification is intended to increase the likelihood that at least one large cell is favorably positioned relative to each coronary ostium. However, prospective data evaluating selective coronary cannulation through these large cells and the relationship between large-cell orientation, commissural alignment, and coronary anatomy in clinical practice remain limited.

The study will enroll approximately 122 patients aged 65 years or older with severe aortic stenosis undergoing TAVI with the Evolut FX Plus valve. Immediately after valve implantation, selective cannulation of the left and right coronary arteries through the large-cell frame will be attempted using standard diagnostic coronary catheters. The primary endpoint is the successful selective coronary cannulation rate through the Evolut FX Plus large-cell frame, assessed separately for the left and right coronary arteries. Successful selective coronary cannulation is defined as stable engagement of a diagnostic catheter at the coronary ostium allowing coronary contrast injection.

Cardiac computed tomography (CT) performed 3 to 6 months after TAVI will provide a detailed assessment of the spatial relationship between the implanted transcatheter heart valve and the coronary ostia. CT-based assessments will include large cell-to-coronary alignment, alignment between the center of the transcatheter valve leaflet and the coronary ostium, and commissural alignment between the native and transcatheter aortic valves. Follow-up CT will also be used to evaluate findings of valve thrombosis, including leaflet, supravalvular, subvalvular, and sinus hypoattenuation.

TAVI will be performed according to standard clinical practice. A commissural alignment technique will be used during valve implantation, with appropriate orientation of the delivery system and fluoroscopic assessment during valve deployment.

Immediately after valve implantation, selective coronary cannulation of the left coronary artery and right coronary artery through the Evolut FX Plus large-cell frame will be attempted using standard diagnostic coronary catheters. The primary endpoint is the successful selective coronary cannulation rate through the large-cell frame, assessed separately for the left and right coronary arteries. Successful selective coronary cannulation is defined as stable engagement of the diagnostic catheter at the coronary ostium allowing coronary contrast injection.

Cardiac CT performed 3 to 6 months after TAVI will be analyzed to assess the spatial relationship between the implanted valve and the coronary ostia. CT-based assessments will include large cell-to-coronary alignment, alignment between the center of the transcatheter valve leaflet and the coronary ostium, commissural alignment between the native and transcatheter aortic valves, and findings of valve thrombosis, including leaflet, supravalvular, subvalvular, and sinus hypoattenuation.

Clinical efficacy and safety outcomes will be assessed at 30 days and 6 months. Clinical events will be defined according to Valve Academic Research Consortium-3 (VARC-3) criteria where applicable.

Inclusion Criteria:

1. Patients with severe aortic stenosis undergoing TAVI with the Evolut FX Plus transcatheter heart valve.
2. Age ≥65 years.
3. Ability and willingness to provide written informed consent for participation in the study.

Exclusion Criteria:

1. Inability to undergo contrast-enhanced cardiac CT before TAVI.
2. Anomalous origin of a coronary artery.
3. Bicuspid aortic valve.
4. Previous surgical or transcatheter aortic valve replacement.
5. Cardiogenic shock or hemodynamic instability.
6. Chronic kidney disease stage 3b, 4, or 5, defined as estimated glomerular filtration rate (eGFR) <45 mL/min/1.73 m².
7. Thrombocytopenia (platelet count <100,000/μL) or an increased bleeding risk precluding antiplatelet or anticoagulant therapy.
8. Allergy or hypersensitivity to aspirin or clopidogrel precluding antiplatelet therapy in patients without an indication for oral anticoagulation.