Cerebral Regional Oxygen Saturation During TAVI - The CROS-TAVI Prospective Registry

This is a prospective, randomized, single-center, interventional clinical study conducted at the Fondazione Policlinico Universitario A. Gemelli IRCCS in Rome, Italy. The study aims to investigate differences in cerebral regional oxygen saturation (rSO₂) during transcatheter aortic valve implantation (TAVI) using different transcatheter heart valve (THV) technologies.

Aortic valve stenosis (AVS) is the most common valvular disease in the elderly, and TAVI has become a widely accepted therapeutic option in high-, intermediate-, and low-risk patients. However, the rapid ventricular pacing, balloon dilatation, and valve deployment involved in TAVI may induce transient cerebral hypoperfusion. This study utilizes near-infrared spectroscopy (NIRS) as a non-invasive method to monitor cerebral oxygenation in real-time during the procedure.

The primary objective is to evaluate the variation in rSO₂ during specific procedural phases and determine whether the type of valve used (balloon-expandable vs. self-expanding) impacts cerebral perfusion. A secondary aim is to identify a potential threshold value of rSO₂ below which prolonged hemodynamic recovery may occur. The study also explores the association between cerebral desaturation and clinical outcomes such as in-hospital mortality, stroke, and postprocedural delirium.

Patients with symptomatic severe aortic stenosis meeting specific inclusion/exclusion criteria will be enrolled and randomized 1:1 to receive:

Group A: A balloon-expandable valve (SAPIEN platform, Edwards Lifesciences)

Group B: A self-expanding valve (SEV)

Patients in Group B will be further randomized to receive:

Group B1: Intra-annular SEV (NAVITOR, Abbott)

Group B2: Supra-annular SEV (EVOLUT, Medtronic)

Cerebral rSO₂ will be monitored bilaterally using INVOS 5100C NIRS sensors placed on the forehead. Measurements will be recorded at six procedural time points: baseline (pre-induction), start of procedure, during pre-dilatation (if performed), at valve deployment, at the lowest rSO₂ during deployment, post-dilatation (if performed), and end of procedure.

Neurocognitive status will be assessed pre-procedure using the Mini-Mental State Examination (MMSE). Postoperative delirium will be monitored using the CAM-ICU and RASS scales. Clinical and procedural data, including rapid ventricular pacing parameters, valve type, and any need for resheathing, will also be recorded.

The primary endpoint is the comparison of mean nadir rSO₂ values between balloon-expandable and self-expanding valve groups. Exploratory analyses will evaluate differences among all three groups (A, B1, B2). Secondary endpoints include in-hospital death, stroke, and delirium incidence.

A total of 40 patients will be enrolled (20 in Group A, 10 in B1, 10 in B2). The study is no-profit, does not involve investigational drugs or unapproved devices, and all THVs used are CE-marked and clinically approved. The protocol has been approved by the local ethics committee (CET Lazio Area 3, ID 7257).

The findings of this study may provide novel insights into the role of cerebral oxygenation monitoring during TAVI and contribute to optimizing valve selection and procedural strategies to improve neurologic and hemodynamic outcomes.

Inclusion criteria

Signed informed consent prior to any study-specific procedures

Diagnosis of severe degenerative aortic valve stenosis with echocardiographic criteria:

Mean gradient > 40 mm Hg, or

Jet velocity > 4.0 m/s, or

Aortic valve area (AVA) < 0.8 cm² (or AVA index < 0.5 cm²/m²)

Symptomatic aortic stenosis defined as NYHA functional class ≥ II

Exclusion criteria

Symptomatic carotid artery disease or indication for carotid revascularization

Cardiogenic shock or inotropic support required prior to the procedure

Active neurodegenerative disease

Contraindications as determined by anesthesiology screening

Age < 18 years

Contraindications to NIRS monitoring

ST-elevation myocardial infarction or cardiogenic shock within 48h before enrollment

Emergency TAVI due to decompensated AV stenosis

Malignancy or comorbidities with life expectancy < 12 months

Inability to comply with the study protocol

Stroke or transient ischemic attack within 6 months

Renal insufficiency (creatinine > 3.0 mg/dL) or dialysis dependency

Severe left ventricular dysfunction (LVEF < 30%)

Significant mixed valvular disease (e.g., severe mitral or tricuspid regurgitation)

Intracardiac mass, thrombus, or vegetation

Chronic corticosteroid use

Participation in another investigational drug or device study

Active bacterial endocarditis or other active infections