Surgical vs Transcatheter Aortic Valve Replacement in YOUNG Patients

Secondary Endpoint: Individual components of the primary endpoints: Bleeding Events (VARC-3 Type 1, 2, and 3) Over Time

Number of participants experiencing bleeding events classified as VARC-3 type 1 (BARC 3a), type 2 and 3. * Scoring System: Valve Academic Research Consortium (VARC) scale: * 1 * Overt bleeding not requiringing surgical or percutaneous intervention, but requiring medical intervention, leading to hospitalization, an increased level of care, or medical evaluation * Overt bleeding requiring a transfusion of 1 unit of whole blood/RBC * 3 * Overt bleeding in a critical organ, such as intracranial, intraspinal, intraocular, pericardial or intramuscular with compartment syndrome * Overt bleeding causing hypovolemic shock or severe hypotension * Overt bleeding requiring reoperation, surgical exploration, or re-intervention for the purpose of controlling bleeding * Post-thoracotomy chest tube output ≥2 L within 24-h * Overt bleeding requiring a transfusion of ≥5 units of whole blood/RBC * Overt bleeding associated with a haemoglobin drop ≥5 g/dL * Higher scores indicate worst outcomes

Time frame: 1, 2, 3, 4, 5, 7, 9, and 10 years

Secondary Endpoint: Individual components of the primary endpoints: Acute Kidney Injury (AKI) Stage 2-4 Over Time

Number of participants with acute kidney injury (AKI) stage 2-4 based on VARC-3 * Scale Information: AKI from Valve Academic Research Consortium 3 (VARC-3): * Scoring System: * Stage 1: AKI that fulfils at least one of the following criteria: * Increase in serum creatinine ≥150-200% (≥1.5-2.0x increase) within 7 days compared with baseline * Increase of ≥ 0.3mg/dL (≥26.4 μmol/L) within 48 h of the index procedure o Stage 2: AKI that fulfils the following criterion: * Increase in serum creatinine \>200-300% (\>2.0-3.0x increase) within 7 days compared with baseline o Stage 3: AKI that fulfils at least one of the following criteria: * Increase in serum creatinine \>300% (\>3.0x increase) within 7 days compared with baseline * Serum creatinine ≥4.0 mg/dL (≥354 μmol/L) with an acute increase of ≥0.5 mg/dL (≥44 μmol/L) * Stage 4: AKI requiring new temporary or permanent renal replacement therapy * Interpretation: Higher stages indicate more severe kidney injury

Time frame: 1, 2, 3, 4, 5, 7, 9, and 10 years

Secondary Endpoint: Individual components of the primary endpoints: Rehospitalization for Procedure-Related Event Over Time

Number of participants requiring rehospitalization due to procedure-related complications.

Time frame: 1, 2, 3, 4, 5, 7, 9, and 10 years

Secondary Endpoint: Individual components of the primary endpoints: Reintervention for Aortic Valve Dysfunction Over Time

Number of participants requiring reintervention (redo-TAVR, SAVR, or valve explantation) due to aortic valve dysfunction.

Time frame: 1, 2, 3, 4, 5, 7, 9, and 10 years

Secondary Endpoint: Feasibility of re-TAVR based on CT scan evaluation (CT scan, for selected sites only)

Number of participants in whom redo-TAVR is deemed feasible based on CT scan evaluation. Feasibility will be assessed using predefined anatomical criteria, including: Annular dimensions Coronary access Valve frame interactions Need for leaflet modification techniques Feasibility will be categorized as: "Feasible without modification," "Feasible with modification," or "Not feasible.

Time frame: 1 month post procedure

Secondary Endpoint: Number of Participants Requiring New Permanent Pacemaker Implantation (PPI) Due to Conduction System Disturbances

Number of participants who require a new permanent pacemaker implantation (PPI) within 1 month post-procedure due to conduction system disturbances (e.g., high-degree atrioventricular block, left bundle branch block). Indications for PPI will be based on standard clinical guidelines.

Time frame: 1 month post procedure

Secondary Endpoint: Rate of prosthetic valve regurgitation (moderate or severe)

Time frame: 1 year post procedure

Secondary Endpoint: Number of Participants with Major Vascular Complications (VARC-3 Criteria)

Number of participants experiencing major vascular complications within 1 month post-procedure, as defined by VARC-3 criteria. o Scoring System: Valve Academic Research Consortium-3 (VARC-3) criteria o Definition: MAJOR vacular complication: One of the following: • Aortic dissection or aortic rupture • Vascular injury or compartment syndrome resulting in death,VARC type ≥2 bleeding, limb or visceral ischaemia, or irreversible neurologic impairment • Distal embolization (non-cerebral) from a vascular source resulting in death, amputation, limb or visceral ischaemia, or irreversible end-organ damage • Unplanned endovascular or surgical intervention resulting in death, VARC type ≥2 bleeding, limb or visceral ischaemia, or irreversible neurologic impairment • Closure device failure resulting in death, VARC type ≥2 bleeding, limb or visceral ischaemia, or irreversible neurologic impairment

Time frame: 1 month post procedure

Secondary Endpoint: Performance of the aortic valve : Gradients (mean/max) assessed by TTE

Mean and peak aortic valve gradients (mmHg) will be measured by transthoracic echocardiography (TTE) at each follow-up time point. Values will be reported as mean ± standard deviation (SD).

Time frame: 1 year and 3 years post procedure

Secondary Endpoint: Performance of the aortic valve : paravalvular leakage (PVL) grade evaluated by transthoracic echocardiogram (TTE)

Number of participants stratified by paravalvular leakage (PVL) grade (None, Mild, Moderate, Severe), as assessed by TTE. PVL severity will be determined based on echocardiographic parameters defined by the VARC-3 criteria.

Time frame: 1 year and 3 years post procedure

Secondary Endpoint: Performance of the aortic valve : effective orifice are (EOA) evaluated by transthoracic echocardiogram (TTE)

Effective orifice area (EOA) (cm²) measured using the continuity equation on TTE. Values will be reported as mean ± standard deviation (SD).

Time frame: 1 year and 3 years post procedure

Secondary Endpoint: Number of Participants with Structural Valve Deterioration (VARC-3) and/or Requiring Redo-TAVR or Valve Explantation

Number of participants experiencing significant structural valve deterioration (SVD) as defined by VARC-3 criteria. SVD will be assessed by transthoracic echocardiography (TTE) Number of participants requiring redo-TAVR or surgical valve explantation within 5 years and 10 years post-procedure.

Time frame: 5 years and 10 years post procedure

CT Scan Sub Study endpoints: Secondary outcomes : feasibility of redoTAVR or ViV TAVR with or without requiring leaflet modification techniques

Proportion of participants in whom redo-TAVR or ViV-TAVR is feasible, with or without requiring leaflet modification techniques, based on CT scan evaluation. Classification will be based on predefined anatomic and hemodynamic feasibility criteria.

Time frame: 1 month post procedure

CT Scan Sub Study endpoints: Secondary outcomes: prevalence of HALT in both TAVR and SAVR groups

Number of participants with HALT detected on CT scan in both TAVR and SAVR groups. HALT will be defined as the presence of hypo-attenuated leaflet thickening observed on post-procedure CT imaging.

Time frame: 1 month post procedure

CT Scan Sub Study endpoints: Secondary outcomes: Impact of HALT on Mean Transvalvular Gradient - Valve Hemodynamics

* Outcome Measure: Mean change in mean transvalvular gradient (mmHg) in participants with and without HALT, measured by transthoracic echocardiography (TTE). * Time Frame: 1 month post-procedure * Unit of Measure: mmHg * Interpretation: A higher mean transvalvular gradient suggests increased valve obstruction.

Time frame: 1 month post procedure

CT Scan Sub Study endpoints: Secondary outcomes: Impact of HALT on Peak Transvalvular Gradient - Valve Hemodynamics

* Outcome Measure: Mean change in peak transvalvular gradient (mmHg) in participants with and without HALT, measured by transthoracic echocardiography (TTE). * Time Frame: 1 month post-procedure * Unit of Measure: mmHg * Interpretation: A higher peak transvalvular gradient indicates greater hemodynamic burden on the valve.

Time frame: 1 month post procedure

CT Scan Sub Study endpoints: Secondary outcomes: Impact of HALT on Effective Orifice Area (EOA) - Valve Hemodynamics

* Outcome Measure: Mean change in effective orifice area (cm²) in participants with and without HALT, measured by transthoracic echocardiography (TTE). * Time Frame: 1 month post-procedure * Unit of Measure: cm² * Interpretation: A lower EOA suggests impaired valve opening and increased risk of stenosis.

Time frame: 1 month post procedure

CT Scan Sub Study endpoints: Secondary outcomes: Mean Transvalvular Gradient - THV Hemodynamics

* Outcome Measure: Mean transvalvular gradient (mmHg) measured by TTE post-implantation. * Time Frame: 1 month post-procedure * Unit of Measure: mmHg * Interpretation: Higher gradients indicate increased obstruction.

Time frame: 1 month post procedure

CT Scan Sub Study endpoints: Secondary outcomes: Peak Transvalvular Gradient - THV Hemodynamics

* Outcome Measure: Peak transvalvular gradient (mmHg) measured by TTE post-implantation. * Time Frame: 1 month post-procedure * Unit of Measure: mmHg * Interpretation: Higher peaks indicate more severe stenosis.

Time frame: 1 month post procedure

CT Scan Sub Study endpoints: Secondary outcomes: Effective Orifice Area (EOA) - THV Hemodynamics

* Outcome Measure: Effective orifice area (cm²) measured by TTE post-implantation. * Time Frame: 1 month post-procedure * Unit of Measure: cm²

Time frame: 1 month post procedure

CT Scan Sub Study endpoints: Secondary outcomes: Commissural Alignment of THV

Mean commissural misalignment angle (degrees) measured by CT scan to evaluate THV positioning relative to native aortic valve commissures.

Time frame: 1 month post procedure