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Completed

NCT Number: NCT02304276

18F-Fluoride Assessment of Aortic Bioprosthesis Durability and Outcome

This study will evaluate the two main types of replacement tissue heart valve used in current practice, comparing outcomes from surgical aortic valve replacement (AVR) with that of the more recently introduced "key-hole" procedure called transcatheter aortic valve implantation (TAVI). Participants will be recruited at various time points ranging from 1 month to 10 years following valve replacement with either AVR or TAVI. It is thought that progressive calcium (chalk) formation is responsible for the failure of the majority of these valves. All participants will therefore have a PET-CT scan with a special type of "tracer" called 18F-fluoride in order to measure active calcium formation in the valve. They will then have annual clinical follow-up for 5 years and be invited back for a repeat CT scan at 2 years to measure change in calcium burden. This study aims to investigate, firstly, the effects of valve age and type on calcium formation as measured by PET-CT and, secondly, whether this measure of calcium formation can help to predict how long different types of valve will last. If successful, 18F-fluoride PET-CT could become a valuable tool for testing new treatments to improve valve longevity and new valve designs.

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Key information

Conditions

Heart; Complications, Valve, Prosthesis

Age range

40 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

About this study

Aortic stenosis is the commonest form of valve disease in the western world and the leading indication for valve surgery. Bioprosthetic valves are known to degenerate via a process that is predominantly driven by calcification. Transcatheter aortic valve implantation (TAVI) has recently emerged as a less invasive alternative to conventional aortic valve replacement (AVR) surgery. Whilst this technique holds great promise, long-term follow up data are lacking and the longevity of these valves remains to be established.

In this longitudinal, cross-sectional study of 180 subjects with either surgical or transcatheter implanted bioprostheses, this study proposes to look for the earliest signs of active calcification using 18F-fluoride positron emission tomography (PET). During a 5 year follow-up period, this study hopes to demonstrate that 18F-fluoride PET will predict subsequent bioprosthetic valve degeneration and identify patients at risk of premature valve failure. The study also hopes that it will inform about the comparative durability of novel percutaneous valves. If successful, 18F-Fluoride could provide a useful method of assessing novel therapeutic strategies targeted at improving the longevity of bioprostheses and help to guide future valve design.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Cohort 1

  • able to provide informed consent
  • aged over 40 years
  • patients with a bioprosthetic aortic valve who are due to undergo a redo-surgical aortic valve replacement

Cohort 2

  • able to provide informed consent
  • aged over 40 years
  • patients at 1 month (n=10), 2 years (n=20), 5 years (n=20) and 10 years (n=20) following surgical bioprosthetic aortic valve replacement

Cohort 3

  • able to provide informed consent
  • aged over 40 years
  • patients at 1 month (n=10), 2 years (n=20) and 5 years (n=20) following transcatheter aortic valve implantation (TAVI) with the Edward's SAPIEN and the COREVALVE.

Exclusion criteria

  • Inability to give informed consent
  • Pregnancy
  • Breastfeeding
  • Claustrophobia
  • Allergy to iodinated contrast
  • Liver failure
  • Chronic kidney disease (with estimated glomerular filtration rate <30 mL/min)
  • Metastatic malignancy
  • Paget's disease

Treatment and study plan

18F-Fluoride PET-CT

Radiation

Injection of 18F-Fluoride with target activity 125MBq giving an anticipated radiation exposure of 3mSv CT scanning protocol giving an anticipated radiation exposure of 13mSv

CT calcium score of aortic valve

Radiation

CT associated with an anticipated radiation exposure of 3mSv (Cohorts 2 and 3 only)

Primary outcomes

  1. 18F-Fluoride uptake in aortic bioprostheses

    Time frame: Baseline

    18F-Fluoride uptake expressed as tissue to background ratio (TBR) in aortic valve bioprostheses of different age and type as measured by PET/CT

Secondary outcomes

  1. CT calcium score of aortic valve

    Time frame: Baseline and 2 years

    Change in aortic valve calcium score (Agatston units) from baseline to 2 years as determined by CT

  2. Echocardiographic evaluation of aortic valve function

    Time frame: Baseline, 1 year and 2 years

    Change in echocardiographic parameters of aortic valve function (both stenosis and regurgitation) from baseline to 1 year and 2 years as determined by Doppler echocardiography

  3. Frequency of major adverse cardiovascular events

    Time frame: 5 years

    Frequency of major adverse cardiovascular events (cardiovascular death, myocardial infarction, stroke, admission with heart failure, repeat valve surgery) as determined by annual clinical follow-up of study population over 5 years

  4. Immunohistochemical staining of explanted aortic bioprostheses for marker of calcification

    Time frame: intraoperative

    Immunohistochemical staining for markers of mineralisation (alkaline phosphatase, Runx-2, osteocalcin) in explanted aortic valve bioprostheses expressed as a percentage of total valve surface area.

Sponsors and collaborators

Lead sponsor

University of Edinburgh

Other

Collaborators

  • Bichat Hospital
  • Cambridge University Hospitals NHS Foundation Trust
  • NHS Lothian
  • Papworth Hospital NHS Foundation Trust

Registry information

Acronym: 18F-FAABULOUS

Important dates

Study start
2015
Primary completion
2018
Study completion
2020
First posted
Dec 1, 2014
Registry last updated
May 21, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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