This clinical trial, a prospective, randomized, multicenter study, assigns patients to either videodensitometry-guided TAVI or conventional TTE/TEE-guided TAVI (stand of care), with the primary endpoint being regurgitation fraction measured by cardiac magnetic resonance (CMR) at discharge. Current AR assessment methods, like subjective visual grading or intraprocedural TTE, face limitations in objectivity and practicality, whereas videodensitometry offers real-time, quantitative feedback to guide corrective actions (e.g., post-dilation) during TAVI. If proven non-inferior, this approach could streamline workflows by reducing reliance on general anesthesia and complex imaging, potentially lowering complications and expanding accessibility, particularly in centers lacking advanced echocardiography resources.

As the transcatheter aortic valve implantation (TAVI) procedure matures, complications such as paravalvular regurgitation (PVR), stroke, conduction disturbances, vascular complications, and annular rupture have been targeted for further improving the long-term outcome of TAVI. Paravalvular regurgitation (PVR) is associated with mortality following TAVI, even in those with mild PVR. Accurate procedural assessment of AR-critical for successful TAVI. Aortic root angiography, typically using Seller's visual grading, is the first screening tool used in most laboratories for the detection of post-implantation AR and guidance of timely corrective measures (e.g. post-dilation, valve-in-valve and, most recently, retrieval and reposition of the valve). However, the Sellers classification of aortic regurgitation (AR) is subjective. Some centers use transthoracic echo to confirm residual AR. However, performing transthoracic echo in the Cath-lab in a prone position is challenging. Previous studies have demonstrated that TAVI performed exclusively under angiographic guidance with backup TTE is feasible and associated with reasonably good outcomes, similar to those of angiography and TEE-guided procedures. Quantitative aortographic assessment of AR is important for procedural TAVI guidance to facilitate timely decision-making to avert AR using balloon post-dilatation, retrieval-reposition, or valve-in-valve implantation.

CAAS A-Valve (quantitative assessment of regurgitation with videodensitometry in the left ventricle outflow tract) is a new tool to quantify AR developed by Pie Medical. This tool is an angiographic methodology that proved to be accurate, feasible, reproducible, and predictive of outcomes after TAVI. After extensive validation of this new technology in two different cohorts (from the Brazilian TAVI registry and Bad-Segeberg, Germany), hereby we propose to apply this currently off-line technology to guide decision making in the Cath-lab during TAVI.

The present trial is a prospective, randomized, controlled, open-label, multi-center, non-inferiority trial. The primary objective of this trial is to determine whether TAVI procedure guided by videodensitometric assessment of aortography is non-inferior to TAVI implantation guided by Standard of care (usual practice) in terms of postprocedural quantitative aortic regurgitation. The primary endpoint of the study will be the Cardiac magnetic resonance-derived regurgitation fraction at discharge. This project is the first study to investigate the clinical utility of using video-densitometry in a randomized, controlled clinical trial to guide TAVI procedure. In centers with no current CAAS-A Valve software, Pie Medical will provide a research lease during the study period.

Inclusion Criteria:

1. Subject has aortic stenosis with indication of TAVI implantation as determined by Heart Team.
2. Patient is at least 18 years of age.
3. Signed informed consent. The patient understands and accepts clinical follow-up.

Exclusion Criteria:

1. Subject is not willing to provide an informed consent form, or whose legal heirs object to their participation in the study.
2. If the patient is not suitable for participating in the study, based on the evaluation by the operators.
3. Cardiogenic shock.
4. Significant comorbidities precluding clinical follow-up (as judged by investigators).
5. History of TAVI or SAVR.
6. Renal insufficiency (GFR/MDRD <45 ml/min), which precludes in operator's opinion contrast injection during repeat aortography.