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CompletedNCT05478161EMPIREUpdated Feb 24, 2026

Investigation of the ALLEGRA THV System With a New Delivery System in Patients With Aortic Stenosis or Failed Surgical Bioprosthesis

An interventional study of (ALLEGRA Transcatheter Heart Valve) TAVI in severe calcified aortic stenosis or in failed surgical aortic bioprosthesis in Transcatheter Aortic Valve Implantation, sponsored by NVT GmbH. Completed at 11 sites in 3 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-02-24.

Sponsored by NVT GmbH · Not applicable, Interventional, and Treatment

Phase
Not applicable
Study type
Interventional
Enrollment
137
Allocation
Not applicable
Ages
18 Years and older
Sex
All
01

Study summary

The EMPIRE study confirms the technical performance of the new IMPERIA Delivery System and evaluates the safety and efficacy of the entire ALLEGRA THV System.

The primary endpoint is device success rate at 7 days (discharge from index procedure or 7 days post implant, whichever comes first), as defined by VARC 2.

Based on the outcomes of a study with a similar device and considering a drop-out rate of 5%, 107 patients need to be enrolled in the study.

02

Conditions studied

  • Transcatheter Aortic Valve Implantation

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Keywords

  • TAVI
  • Aortic valve stenosis
  • ALLEGRA
  • IMPERIA
03

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

  1. Symptomatic severe calcific stenosis of a native aortic valve with an AVA ≤1.0 cm2 (or AVA index ≤0.6 cm2/m2), AND mean aortic pressure gradient ≥ 40mmHg OR maximal transaortic velocity ≥4.0m/s OR Doppler velocity index ≤0.25 on site-reported echocardiography OR symptomatic patients with degeneration of a surgical bioprosthetic valve (stenosis +/- insufficiency) on site-reported echocardiography
  2. Local multi-disciplinary Heart Team and Central Screening Committee (CSC) agree on indication and eligibility for TAVI
  3. Age ≥18 years
  4. Patient has signed the Patient Informed Consent Form
  5. Patient is willing and able to comply with requirements of the study, including all follow-up visits

Exclusion criteria

Exclusion Criteria:

General:

  1. Mean aortic annulus diameter as measured by pre-procedural CT or internal diameter of the bioprosthesis is \<16.5 mm or >27 mm
  2. Echocardiographic evidence of intracardiac thrombus or vegetation (site-reported)
  3. Significant disease of the aorta that would preclude safe advancement of the ALLEGRA THV System
  4. Severe ilio-femoral vessel disease that would preclude safe placement of an 18 Fr introducer sheath or make endovascular access impossible
  5. Porcelain aorta
  6. Severe left ventricular dysfunction with ejection fraction (EF) \<20% (site-reported)
  7. Evidence of active endocarditis or other acute infections
  8. Renal failure requiring continuous renal replacement therapy
  9. Untreated clinically significant coronary artery disease requiring revascularization
  10. Any percutaneous interventional procedure (e.g. PCI with stenting) within 14 days prior of the index procedure
  11. Acute MI ≤30 days prior to the index procedure
  12. Symptomatic carotid or vertebral artery disease requiring intervention or carotid/vertebral intervention within the preceding 45 days
  13. Cerebrovascular accident (CVA) or transient ischemic attack (TIA) ≤6 months or prior CVA with moderate or severe disability (e.g. modified Rankin scale score >2)
  14. History of bleeding diathesis or coagulopathy; acute blood dyscrasias as defined: thrombocytopenia (platelets \<80,000/µl), acute anemia (hemoglobin \<10 g/dl), leukopenia (WBC \<3000/ µl)
  15. Active peptic ulcer or gastrointestinal (GI) bleeding ≤3 months
  16. Severe (greater than 3+) mitral insufficiency (site-reported)
  17. Uncontrolled atrial fibrillation
  18. Required emergency surgery for any reason
  19. Known hypersensitivity to contrast media, which cannot be adequately pre-medicated or contraindication to anticoagulant or anti-platelet medication or to nitinol alloy or to bovine tissue
  20. Life expectancy ≤12 months due to other medical illness
  21. Currently participating in another investigational drug or device study

  22. Pregnancy or intend to become pregnant during study participation

    Specific exclusions in patients with native aortic valve disease (site-reported):

  23. Unicuspid or bicuspid aortic valve
  24. Non-calcified aortic stenosis
  25. Predominant aortic regurgitation > grade 3

  26. Distance between native aortic valve basal plane and the orifice of the lowest coronary artery \<8 mm

    Specific exclusions in patients with degenerated surgical bioprosthetic aortic valves (valve-in-valve) (site-reported):

  27. Low position of the coronary ostia, especially in combination with shallow sinuses (high risk of coronary occlusion)
  28. Partially detached leaflets that may obstruct a coronary ostium
04

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
137 participants (actual)

Study arms

  • Experimental
    treatment

    TAVI in severe calcified aortic stenosis or in failed surgical aortic bioprosthesis

    Device: (ALLEGRA Transcatheter Heart Valve) TAVI in severe calcified aortic stenosis or in failed surgical aortic bioprosthesis

Interventions

  • Device(ALLEGRA Transcatheter Heart Valve) TAVI in severe calcified aortic stenosis or in failed surgical aortic bioprosthesis

    Implantation of the ALLEGRA Transcatheter Heart Valve in failing surgical bioprosthesis

05

What researchers measure

Primary outcomes

  1. Device success at 7 days

    * Absence of procedural mortality AND * Correct positioning of a single device in the proper anatomical location (site-reported) AND * Intended performance of the prosthetic heart valve (as determined by an independent Echo Core Lab at discharge from index procedure or 7 days post implant, whichever comes first) * Indexed Effective Orifice Area (iEOA) \> 0.85 cm2/m2 for BMI \< 30kg/m2 and iEOA \> 0.70 cm2/m2 for BMI ≥ 30kg/m2 * Mean aortic valve gradient \<20 mmHg or peak velocity \<3 m/s * No moderate or severe prosthetic valve regurgitation

    Time frame: 7 day

Secondary outcomes

  1. All-cause mortality

    Time frame: up to 12 months

  2. Cardiovascular mortality

    Time frame: up to 12 months

  3. All stroke

    Time frame: up to 12 months

  4. TIA

    Time frame: up to 12 months

  5. Procedural success

    * Successful vascular access, delivery and deployment of the ALLEGRA THV including re- positioning if required and successful retrieval of the IMPERIA Delivery System (site- reported) * Correct position of the ALLEGRA THV (site-reported) * Only one ALLEGRA THV implanted in proper anatomical position (site-reported)

    Time frame: assessed immediately after the procedure

  6. Effective orifice area (EOA) as assessed by transthoracic echocardiogram (TTE)

    Time frame: up to 12 months

  7. Transvalvular mean and peak pressure gradient as assessed by transthoracic echocardiogram (TTE)

    Time frame: up to 12 months

  8. Trans- and paravalvular regurgitation as assessed by transthoracic echocardiogram (TTE)

    Time frame: up to 12 months

  9. NYHA classification

    Time frame: 30 days, 6 months, and 12 months

  10. Early safety

    * All-cause mortality * All stroke (disabling and non-disabling) * Life-threatening bleeding * Acute kidney injury-Stage 2 or 3 (including renal replacement therapy) * Coronary artery obstruction requiring intervention * Major vascular complication * Valve-related dysfunction requiring repeat procedure (BAV, TAVI, or SAVR)

    Time frame: up to 30 days

  11. Time-related valve safety

    * Structural valve deterioration * Valve-related dysfunction (mean aortic valve gradient * 20 mmHg, EOA ≤0.9-1.1 cm2c and/or DVI \<0.35 m/s, AND/OR moderate or severe prosthetic valve regurgitation) * Requiring repeat procedure (TAVI or SAVR) * Prosthetic valve endocarditis * Prosthetic valve thrombosis * Thrombo-embolic events (e.g. stroke) * VARC bleeding, unless clearly unrelated to valve therapy (e.g. trauma)

    Time frame: up to 12 months

  12. Quality of life as assessed using the Kansas City Cardiomyopathy Questionnaire (KCCQ-12)

    Assessed with the Kansas City Cardiomyopathy Questionnaire (KCCQ-12). Patients are asked questions about physical limitation, symptom frequency, quality of life, and social limitation. Responses are given on a Likert scale that for each individual item is scored on a scale of 0-100 with higher scores indicating better health.

    Time frame: up to 12 months

  13. New pacemaker implantation

    Time frame: up to 12 months

  14. Delivery system related AEs

    Time frame: discharge from index procedure or 7 days post implant, whichever comes first

06

Study locations

11 sites
  • Schüchtermann Klinik
    Bad Rothenfelde, Lower Saxony 49214, Germany
  • Herz- und Gefäßzentrum Bad Bevensen
    Bad Bevensen, Germany
  • UKSH, Campus Lübeck
    Lübeck, Germany
  • Catharina Hospital
    Eindhoven, Netherlands
  • Maastricht University Medical Center
    Maastricht, Netherlands
  • Erasmus Medical Center
    Rotterdam, Netherlands
  • Hospital Universitari de Bellvitge
    Barcelona, Spain
  • Hospital Clínico San Carlos
    Madrid, Spain
  • Hospital Universitario Virgen de la Victoria
    Málaga, Spain
  • Hospital Universitario de Salamanca
    Salamanca, Spain
  • Hospital Alvaro Cunqueiro
    Vigo, 36213, Spain
07

Registry details

Key details

Study ID
NCT05478161
Lead sponsor
NVT GmbH
Responsible party
Sponsor
First posted
Jul 28, 2022
Start date
Jan 24, 2023
Primary completion
Dec 20, 2023
Completion
Dec 17, 2024
Last update
Feb 24, 2026

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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