Platelet function in patients undergoing major, non-cardiac, vascular surgery
| ISRCTN | ISRCTN11959105 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN11959105 |
| ClinicalTrials.gov (NCT) | Nil known |
| Clinical Trials Information System (CTIS) | Nil known |
| Integrated Research Application System (IRAS) | 302883 |
| Protocol serial number | IRAS 302883, CPMS 51033 |
| Sponsor | University of Oxford |
| Funder | National Institute of Academic Anaesthesia |
- Submission date
- 25/03/2022
- Registration date
- 14/04/2022
- Last edited
- 11/09/2023
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Surgery
Plain English summary of protocol
Background and study aims
Many patients who require major operations on the blood vessels (vascular surgery) are taking antiplatelet medications. On the day of surgery, they may require an epidural for pain relief. An epidural is an injection in the back that blocks the nerves carrying pain from the area being operated on. It is generally a safe procedure that provides excellent pain relief. One rare risk is bleeding into the injection site, which can have potentially devastating complications such as paralysis. Bleeding into the epidural injection site is estimated to occur in 1 in every 150,000 cases. The risk is thought to be higher in patients who are on antiplatelet medications and therefore guidelines recommend stopping some antiplatelet medications for between 5 and 7 days before an epidural injection. However, this is not based on high-quality research and stopping these medications, even for a brief period, can result in patients being at higher risk of stroke or heart attack. However, little is known about how individual people respond to these medications. Some research suggests that antiplatelet medications may not work in a third of patients. Epidural analgesia may be a suitable option for these patients. Expert committees have called for more research on identifying these patients. The aim of this study is to better understand the true effects that antiplatelet medication has on circulating platelets in the blood.
Who can participate?
Patients aged 18 years and over who are scheduled to undergo major vascular surgery at the John Radcliffe Hospital, Oxford
What does the study involve?
The researchers will require two to three teaspoons of blood from the participants. This blood would be taken during routine pre-operative assessment clinic visits and again on the day of surgery. No drugs will be given as part of the study and the remainder of the study data will be collected from routine healthcare records.
What are the possible benefits and risks of participating?
Participants may not directly benefit from this study but the information and knowledge gained from this study has the potential to help future patients who will undergo vascular surgery. Taking the blood samples may cause some discomfort, bruising of very minor bleeding. If this happens, it can easily be treated by applying pressure on the site where blood was taken from and taking simple painkillers if required.
Where is the study run from?
John Radcliffe Hospital (UK)
When is the study starting and how long is it expected to run for?
September 2020 to June 2023
Who is funding the study?
National Institute of Academic Anaesthesia (NIAA) (UK)
Who is the main contact?
Dr Akshay Shah.
akshay.shah@linacre.ox.ac.uk
Contact information
Principal investigator
Nuffield Department of Anaesthetics
John Radcliffe Hospital
Headley Way
Oxford
OX3 9DU
United Kingdom
 ORCID ID |
0000-0002-1869-2231 |
|---|---|
| Phone | +44 (0)1865387906 |
| akshay.shah@ndcn.ox.ac.uk |
Study information
| Primary study design | Observational |
|---|---|
| Study design | Prospective observational cohort study |
| Secondary study design | Cross sectional study |
| Study type | Participant information sheet |
| Scientific title | PLatelet fUnction in patients undergoinG major, non-cardiac, vascular Surgery (PLUGS) – a prospective cohort study |
| Study acronym | PLUGS |
| Study objectives | To characterise platelet function, using the TEG6S assay, in patients scheduled to undergo elective major, non-cardiac vascular surgery. |
| Ethics approval(s) | Approved 20/12/2021, West Midlands - Solihull Research Ethics Committee (West Midlands - Solihull Research Ethics Committee, Equinox House, City Link, Nottingham, NG2 4LA, UK; +44 (0)207 104 8191, +44 (0)207 104 8310; solihull.rec@hra.nhs.uk), ref: 21/WM/0254 |
| Health condition(s) or problem(s) studied | Participants scheduled to undergo elective, major non-cardiac, vascular surgery |
| Intervention | The aim of this study is to better understand the true effects that antiplatelet medication has on circulating platelets in the blood. The researchers will use novel methods of analysing platelet function. They will aim to recruit 80 patient participants across four study groups who are scheduled to undergo major vascular surgery at the John Radcliffe Hospital, Oxford and who are taking: 1. Aspirin only 2. Clopidogrel only 3. Dual antiplatelets 4. No antiplatelets (control group) There is a growing body of evidence evaluating the relationship between measured platelet function and bleeding in patients on clopidogrel, or similar agents undergoing non-cardiac surgery. However, patient compliance with antiplatelet therapy was not reported in these studies. The gold standard method of assessing platelet function is light transmission aggregometry, but this is a time-consuming, labour-intensive method and requires a large volume of blood in comparison with other methods. Thromboelastography 6S (TEG6S) provides near-patient, real-time information on the viscoelastic properties of clot formation, along with information on platelet mapping and percentage inhibition, and has been approved for clinical use. TEG6 assays will be run in accordance with the manufacturer’s guidelines by a trained member of the research team in the operating theatres of the John Radcliffe Hospital, OUHFT. These will be run within 20-40 minutes of being taken. They will require two to three teaspoons of blood from patients who have agreed to take part. This blood would be taken during routine pre-operative assessment clinic visits and again on the day of surgery. No drugs will be given as part of the study and the remainder of the study data will be collected from routine healthcare records. |
| Intervention type | Other |
| Primary outcome measure(s) |
1. Percentage of patients with antiplatelet drug resistance at initial presentation to the Pre-operative Assessment Clinic and on the morning of surgery. For aspirin group (i), drug resistance will be defined as an arachidonic acid (AA)-induced platelet-fibrin clot strength (MAAA) >47 mm plus an AA-induced platelet inhibition rate < 50%. For P2Y12 inhibitors (clopidogrel) group (ii), drug resistance will be defined as an adenosine diphosphate (ADP)-induced platelet-fibrin clot strength (MAADP) >47 mm plus an ADP-induced platelet inhibition rate < 50% |
| Key secondary outcome measure(s) |
1. Proportion of patients who self-report as being compliant with antiplatelet medications preoperatively. Compliance will be defined as taking >80% of prescribed doses as prescribed. |
| Completion date | 30/06/2023 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 110 Years |
| Sex | All |
| Target sample size at registration | 80 |
| Key inclusion criteria | 1. Participant is willing and able to give informed consent for participation in the study 2. Aged 18 years or above 3. Scheduled to undergo major non-cardiac vascular surgery (including, but not restricted to, abdominal aortic aneurysm (open or endovascular), carotid endarterectomy, lower limb arterial revascularisation) 4. For participants taking antiplatelet therapy: (i) aspirin alone, (ii) clopidogrel alone or (iii) dual antiplatelet therapy groups, at least 7 days of prescribed antiplatelet therapy prior to study recruitment. Patients who are on other antiplatelet therapy, but from the same therapeutic class as either aspirin or clopidogrel, will be allocated to that particular group. 5. Participants in the control group (iv) should not have been on any antiplatelet therapy |
| Key exclusion criteria | 1. Congenital/inherited bleeding disorders 2. Haemodialysis-dependent chronic kidney disease 3. Enrolled into a study where an intervention may affect platelet function – this would be discussed on a case-by-case basis between the study Chief Investigators |
| Date of first enrolment | 09/06/2022 |
| Date of final enrolment | 15/05/2023 |
Locations
Countries of recruitment
- United Kingdom
- England
Study participating centre
Headington
Oxford
OX3 9DU
United Kingdom
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|---|
| IPD sharing plan summary | Data sharing statement to be made available at a later date |
| IPD sharing plan | The data-sharing plans for the current study are unknown and will be made available at a later date |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| HRA research summary | 28/06/2023 | No | No | ||
| Participant information sheet | Participant information sheet | 11/11/2025 | 11/11/2025 | No | Yes |
| Protocol file | version 4.0 | 08/02/2023 | 11/09/2023 | No | No |
Additional files
- ISRCTN11959105 PLUGS_Protocol_V4.0_08Feb2023.pdf
- Protocol file
Editorial Notes
11/09/2023: The following changes were made to the trial record:
1. Uploaded protocol (not peer-reviewed) as an additional file.
2. The intention to publish date was changed from 01/09/2023 to 30/06/2024.
28/06/2023: Internal review.
09/06/2023: The following changes were made to the trial record:
1. The recruitment start date was changed from 04/04/2022 to 09/06/2022.
2. The recruitment end date was changed from 04/04/2023 to 15/05/2023.
05/05/2022: Internal review.
28/03/2022: Trial's existence confirmed by the HRA.
