Participants scheduled to undergo elective, major non-cardiac, vascular surgery Surgery
Conditions
Interventions
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 func
Sponsors
University of Oxford
Eligibility
Sex/Gender
All
Inclusion criteria
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
Exclusion criteria
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
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| 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 47 mm plus an ADP-induced platelet inhibition rate < 50% 2. Percentage of patients with platelet inhibition measured using the TEG6S assay on the morning of surgery | — |
Secondary
| Measure | Time frame |
|---|---|
| 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. 2. Peri-operative blood loss, changes in haemoglobin concentration and transfusion requirements measured using routine healthcare records in the first 24 hours in the first 24 hours 3. Return to theatre for bleeding in the first 24 hours and/or graft/stent thrombosis measured using routine healthcare records in the first 24 hours 4. Peri-operative thrombotic events measured using routine healthcare records within 30 days of surgery 5. Bleeding complications associated with regional anaesthesia measured using routine healthcare records at 30 days 6. Days-alive-and-out-of-hospital at 30 days (DAOH-30) measured using routine healthcare records | — |
Countries
England, United Kingdom
Outcome results
None listed