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NCT Number: NCT06800430

Graft Failure and Consequences of Coronary Artery Bypass Graft Surgery

Coronary artery bypass graft (CABG) surgery is the commonest type of heart operation performed. During this, arteries or veins (termed 'grafts') are used to supply blood around blockages within the blood vessels that supply the heart. Unfortunately, these grafts can sometimes fail, and patients can also experience complications like heart attacks and strokes, after surgery. It is known that vein grafts are more likely to narrow over time. Additionally, treating vein graft failure is very challenging, as repeat surgery is riskier and procedures to stent open the veins can also fail. However, it is not fully understood why these complications occur.

In this study, the investigators will use an imaging technique called a total-body Positron Emission Tomography (PET) scan. This uses special radioactive dyes (radiotracers) to look at what is happening inside vein grafts. With this technique, the investigators will also be able to see what is happening to the heart, brain and wider parts of the body after CABG surgery.

This study will aim to recruit 70 participants in total (maximum 150). 40 (maximum of 120) of these participants will have recently undergone CABG surgery and received ≥1 vein graft. The remaining 30 will have undergone CABG surgery ≥5 years ago and will have symptoms suggestive of vein graft failure.

The study will last a total of 36 months and will involve participants undertaking the following assessments:

1. Total-body Positron Emission Tomography and Computed Tomography (PET-CT) scan 2. Ultrasound scan of the heart (echocardiogram) 3. A blood test - up to four tablespoons (60 mL) of blood will be taken for immediate testing and the remainder will be stored for future ethically approved studies.

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Key information

Conditions

Coronary Artery Bypass Cardiovascular Diseases Coronary Artery Bypass Graft Coronary Artery Bypass Graft Surgery (CABG) Graft Failure Heart Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Royal Infirmary of Edinburgh

Edinburgh, Midlothian, EH16 4SA, United Kingdom

Location status: Recruiting

Location contact

Laura E Clark, MBChB BSC(Hons)

PRINCIPAL_INVESTIGATOR

Laura E Clark, MBChB BSc(Hons)

CONTACT

[email protected]

+447717478087

About this study

This is an observational cohort study investigating the role of inflammation, thrombosis and fibrosis in saphenous vein graft failure following CABG surgery. The presence and distribution of these processes will be examined in one cohort overtime (immediately following surgery and at 1 year-follow up) and at one time-point in a second cohort with clinically suspected vein graft failure.

Participants in both cohorts will undergo clinical review (including blood sampling), transthoracic echocardiogram and combined total-body positron emission tomography computed tomography (PET-CT) imaging, with CT coronary angiography.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

Cohort 1: Patients undergoing CABG surgery

  • Males and females over 18 years of age
  • Patients undergoing CABG surgery for multivessel coronary artery disease, who receive at least one saphenous vein graft

Cohort 2: Patients with symptomatic saphenous vein graft vasculopathy

  • Males and females over 18 years of age
  • Patients who underwent CABG surgery ≥ 5 years prior to recruitment for multivessel disease and received 2 or more saphenous vein grafts
  • Referred for invasive coronary angiography due to recurrent symptoms and with a high suspicion of graft vasculopathy

Exclusion criteria

  • Patients with a life expectancy of < 2 years
  • Renal failure (estimated glomerular filtration rate <30 mL/min/1.73 m2)
  • Patients on immunosuppressive therapies
  • Females of child-bearing age who are pregnant or breastfeeding,
  • Known allergy or contraindications to iodinated contrast or radiotracer
  • Patients who are unable to tolerate the supine position
  • Patients who are unable to provide informed consent

Treatment and study plan

Hybrid [18F]-GP1, [68Ga]-DOTATATE, [68Ga]-FAPI total-body positron emission tomography and coronary computed tomography coronary angiography

Radiation

Patients undergo hybrid [18F]-GP1, [68Ga]-FAPI and [68Ga]-DOTATATE total body PET-CT imaging (Biograph Vision Quadra, Siemens) and contrast-enhanced electrocardiogram gated CT coronary angiogram (CTCA), within 28 days (+/- 28 days) of their CABG surgery and again at 12 month follow-up.

Primary outcomes

  1. Platelet activation

    Time frame: 3 years

    The degree and location of platelet activation within saphenous vein grafts, measured using standard uptake values and tissue-to-background ratios of [18F]-GP1.

  2. Fibroblast activation

    Time frame: 3 years

    The degree and location of fibroblast activation within saphenous vein grafts, measured using standard uptake values and tissue-to-background ratios of [68Ga]-FAPI.

  3. Macrophage activation

    Time frame: 3 years

    The degree and location of macrophage activation within saphenous vein grafts, measured using standard uptake values and tissue-to-background ratios of [68Ga]-DOTATATE.

Secondary outcomes

  1. Systemic cardiovascular disease

    Time frame: 3 years

    The secondary endpoints will include the presence of systemic thrombotic, fibrotic or inflammatory cardiovascular disease, assessed through biomarker and CT imaging analyses.

Study contacts

Contact information is provided by the study sponsor or research team.

David E Newby, BSc (Hons) PhD BM DM DSc FRCP

CONTACT

[email protected]

Laura E Clark, BSc, MBChB, MRCS(Ed)

CONTACT

[email protected]

+447717478087

Sponsors and collaborators

Lead sponsor

University of Edinburgh

Other

Collaborators

  • NHS Lothian

Registry information

Official study title

Vein Graft Failure and Cardiovascular Consequences of Coronary Artery Bypass Graft Surgery

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Jan 30, 2025
Registry last updated
Apr 20, 2026

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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