SYMmetric Valve fraME Expansion To Reduce hYpoattenuated Leaflet Thickening After Balloon-expandable TAVI: the SYMMETRY Trial

Trial statusNot yet recruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age70+
SponsorErasmus Medical Center

About this trial

Rationale: Transcatheter aortic valve implantation (TAVI) has become the standard of care for aortic stenosis across all surgical risk categories, including low-risk, younger patients (≥70 years). As many of these patients are expected to outlive their prosthetic valves, the durability of the valve becomes an increasingly critical factor. Hypoattenuated leaflet thickening (HALT), a finding on post-TAVI computed tomography (CT), occurs in approximately 20% of patients and is associated with bioprosthetic valve dysfunction. Balloon-expandable valves seem more susceptible to HALT with an occurrence rate of 21%, compared to 16% for self-expanding valves.

A recent study identified underexpansion of the transcatheter heart valve prosthesis as a key predictor of HALT at 30 days, which in turn was associated with a sixfold increase in cardiovascular mortality and a threefold increase in all-cause mortality at 1 year. Moreover, data suggest that, in the absence of post-dilatation, more than 95% of balloon-expandable valve implants exhibit some degree of underexpansion. In contrast, routine post-dilatation enhances valve expansion and hemodynamic performance without significantly increasing adverse events. The double-TAP technique-re-inflation of the TAVI delivery balloon after initial valve deployment-achieves a 9-10% increase in valve frame expansion, potentially reducing HALT risk and improving long-term outcomes.

Objective: To determine whether routine double-TAP post-dilatation after balloon-expandable TAVI is safe and can reduce the incidence of HALT.

Study design: Investigator-initiated, multicenter, open-label, randomized trial with 1:1 allocation to routine post-dilatation using double-TAP versus no post-dilatation immediately after balloon expandable valve deployment.

Study population: 422 Patients undergoing balloon-expandable TAVI for native aortic valve stenosis Investigational intervention: TAVI with a balloon-expandable valve followed by double-TAP post-dilatation.

Study design: Investigator-initiated, multicenter, open-label, randomized trial with 1:1 allocation to routine post-dilatation using double-TAP versus no post-dilatation immediately after balloon expandable valve deployment.

Study population: 422 Patients undergoing balloon-expandable TAVI for native aortic valve stenosis

Investigational intervention: TAVI with a balloon-expandable valve followed by double-TAP post-dilatation.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

Age ≥ 70 years

Patients with severe aortic stenosis undergoing TAVI with a balloon-expandable valve

Written informed consent

Disqualifiers

Significant valve frame under-expansion and/or ≥ moderate paravalvular leakage warranting post-dilatation at the discretion of the treating physician

Shallow implantation depth with increased risk of valve embolization upon post-dilatation

Sievers type 1 bicuspid aortic valve with calcified raphe

Indication for oral anticoagulant therapy

Trial design

Design model

Parallel

Treatments tested in this trial

  • Double-TAP post-dilatation

    Procedure/Surgery

    If patient is randomized to treatment arm the TAVI delivery balloon is aligned at valve level and reinflated to nominal volume for 3 seconds under rapid pacing.

Treatment groups

422 Participants
are divided into 2 treatment groups
Group A: Double-TAP post-dilatationActive comparator 1 intervention
Group B: No post-dilatationNo intervention 0 interventions

Trial outcomes

Primary outcomes

1

Hypoattenuated Leaflet Thickening (HALT)

HALT (at least one thickened TAV leaflet involving \> 25% of the leaflet curvilinear dimension as assessed at cardiac CT)

Time frame
30 days
2

Co-primary (safety) endpoint

Composite of 1) freedom from all-cause mortality; 2) freedom from all new stroke; 3) freedom from VARC type 2 to 4 bleeding; 4) freedom from major vascular, access-related, or cardiac structural complications; 5) freedom from acute kidney injury stage 3 or 4; 6) freedom from moderate or severe aortic regurgitation; 7) freedom from new permanent pacemaker implantation caused by procedure related conduction abnormalities; and 8) freedom from surgery or intervention related to the device in accordance with the third Valve Academic Research Consortium (VARC-3) criteria at 30 days.

Time frame
30 days

Secondary outcomes

Other outcomes

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

Erasmus Medical Center

Lead sponsor

Edwards Lifesciences

Collaborator

This trial is not recruiting at the moment. You can still explore other options: