NVT ALLEGRA TAVI System TF in Failing Calcified Aortic Heart Valves in a Real-world Patient Population (FOLLOW)

Clinical Outcomes of the NVT ALLEGRA TAVI System TF in Failing Calcified Aortic Heart Valves in a Real-world Patient Population With Elevated Surgical Risk

The study collects real-world data of patients who were treated with the ALLEGRA TAVI System TF and evaluates early and midterm clinical and quality of life outcome.

Study Overview

• Status: Active, not recruiting
• Conditions: Transcatheter Aortic Valve Implantation

• Study Type: Observational
• Enrollment (Actual): 346

Contacts and Locations

Study Locations

• Finland
  • Oulu, Finland, 90220
    • Oulu University Hospital
• Germany
  • Bad Bevensen, Germany, 29549
    • Herz- und Gefasszentrum Bad Bevensen
  • Bad Rothenfelde, Germany
    • Schuechtermann-klinik
  • Hamburg, Germany, 22087
    • Kath. Marienkrankenhaus
  • Hanover, Germany, 30625
    • MH Hannover
  • Heilbronn, Germany, 74078
    • SLK-Kliniken Heilbronn
• Italy
  • Milan, Italy, 20132
    • Ospedale San Raffaele
  • Naples, Italy
    • Clinica Mediterranea Neapel
• Netherlands
  • Eindhoven, Netherlands, 5623 EJ
    • Heartcentre Catharina Hospital Eindhoven
• Spain
  • Madrid, Spain, 28046
    • Hospital Universitario La Paz
  • Málaga, Spain, 29010
    • Hospital Universitario Virgen de la Victoria
  • Salamanca, Spain, 37007
    • Hospital Universitario de Salamanca
  • Vigo, Spain, 36213
    • Hospital Álvaro Cunqueiro
• United Kingdom
  • Swansea, United Kingdom
    • Morriston Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Symptomatic patients with elevated surgical risk and candidate for TAVI with severe calcified and stenotic aortic valves or failing surgical bioprosthetic aortic valves.

Description

Inclusion Criteria:

1. Symptomatic degeneration of severe calcified aortic heart valve OR failing surgical aortic bioprosthetic valve
2. Acceptable candidate for elective treatment with the ALLEGRA TAVI System TF (according to the most recent version of the ALLEGRA Instructions For Use)
3. High risk for surgery as assessed by the heart team
4. Has signed the Patient Informed Consent Form >= 18 years

Exclusion Criteria:

General:

1. Echocardiographic evidence of intracardiac thrombus or vegetation
2. Significant aortic disease such as severe obstructive calcification or marked tortuosity or kinking which will preclude a safe advancement of the ALLEGRA TAVI System TF
3. Iliofemoral vessel conditions such as severe obstructive calcification, severe tortuosity or kinking that would preclude safe placement of an 18 Fr introducer sheath or make endovascular access to the aortic valve impossible
4. Severe ventricular dysfunction with LVEF <20%
5. Evidence of active endocarditis or other acute infections
6. Renal failure requiring continuous renal replacement therapy
7. 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
8. Life expectancy ≤ 12 months due to other medical illness
9. Currently participating in another investigational drug or device study

Patients with native aortic valve disease:

1. Unicuspid or bicuspid aortic valve
2. Non-calcified aortic stenosis
3. Combined aortic valve disease with predominant aortic regurgitation > 3
4. Distance between aortic valve basal plane and the orifice of the lowest coronary artery < 8 mm

Patients with degenerated surgical bioprosthetic aortic valves:

1. Low position of the coronary ostia, especially in combination with shallow sinuses
2. Internal diameter of the bioprosthesis is ≤16 mm or >28 mm
3. Partially detached leaflets that in the aortic position may obstruct a coronary ostium

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Cohort 1: Patients who undergo TAVI for symptomatic severe stenosed aortic heart valves
Cohort 2: patients undergoing a VIV procedure in failing surgical bioprostheses.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Cardiovascular death	30 days post-index procedure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Technical success of implantation	Technical success of implantation, as defined by: absence of procedural mortality AND; correct positioning of a single prosthetic heart valve into the proper anatomical location AND; no prosthesis - patient mismatch AND; mean aortic valve gradient <20 mmHg, AND; no moderate or severe prosthetic valve regurgitation	day of procedure
Safety profile according to VARC II	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 Time-related valve safety; Structural valve deterioration as defined byRequiring repeat procedure (transcatheter or surgical heart valve replacement)Valve-related dysfunction defined bymean aortic valve gradient ≥20 mmHg andno moderate or severe prosthetic valve regurgitation; Prosthetic valve endocarditis; Prosthetic valve thrombosis; Thrombo-embolic events (e.g. stroke); VARC bleeding, unless clearly unrelated to valve therapy	30 days
In-hospital mortality		date of procedure till date of estimated discharge, assessed up to two weeks
All-cause mortality		up to five years
Assesment of NYHA classification		30 days, 12 month, 24 month, 36 month, 48 month, 60 month
Quality of life (EQ5D 5L)		30 days, 12 month, 24 month, 36 month, 48 month, 60 month
New pacemaker implantation		up to five years
assessment of mean aortic gradient post-implantation		up to five years

Collaborators and Investigators

• Sponsor: NVT GmbH
• Investigators: Principal Investigator: Ulrich Schäfer, MD, Herz-und Gefäßzentrum Bad Bevensen, Germany

Study record dates

Study Major Dates

• Study Start (Actual): February 20, 2019
• Primary Completion (Actual): December 20, 2024
• Study Completion (Estimated): January 26, 2029

Study Registration Dates

• First Submitted: July 6, 2018
• First Submitted That Met QC Criteria: July 27, 2018
• First Posted (Actual): August 3, 2018

Study Record Updates

• Last Update Posted (Estimated): November 17, 2025
• Last Update Submitted That Met QC Criteria: November 13, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Aortic valve stenosis; TAVI; ALLEGRA
• Additional Relevant MeSH Terms: Aortic Valve Disease; Cardiovascular Diseases; Heart Diseases; Heart Valve Diseases; Ventricular Outflow Obstruction; Aortic Valve Stenosis
• Other Study ID Numbers: NVT04FOL

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No