Predicting Endoleaks Following Endovascular Aortic Aneurysm Repair Using 18F-Sodium Fluoride

Study Overview
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Brief Summary
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The purpose of the study is to describe Sodium Fluoride uptake (using Positron Emission Tomography-Computed Tomography - PET-CT) following Endovascular Aneurysm Repair (EVAR) and to determine whether Sodium Fluoride PET-CT can predict the development of endoleaks.

Detailed Description
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Abdominal aortic aneurysms are a leading cause of death in the United Kingdom. Surveillance programmes and pre-emptive surgical repair are lifesaving. Traditional open surgical repair is associated with major perioperative morbidity and mortality and there has been a move towards minimally invasive Endovascular Aneurysm Repair (EVAR), which reduces these early risks. However, the cost effectiveness and long-term clinical effectiveness of EVAR is undermined by concerns of durability due to the development of endoleaks and late aneurysm rupture secondary to progression of native aortic aneurysm disease and stent graft failure. It has previously been demonstrated that 18F-Sodium Fluoride Positron Emission Tomography can predict progression of aneurysm disease and is associated with greater rates of abdominal aortic aneurysm expansion and the future risk of rupture or surgical repair. The investigators here wish to examine whether 18F-Sodium Fluoride on Positron Emission Tomography uptake (i) is increased in patients with endoleaks or related complications, (ii) can prospectively predict the likelihood of developing endoleaks in patients undergoing EVAR, and (ii) is a feasible approach to select patients for EVAR with a reduced future risk of stent graft failure and re-intervention. The investigators believe that there is a compelling scientific rationale for this approach with major translational potential to better select subgroups of patients for EVAR and ultimately improve their outcome.

Official Title
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The PET-EVAR Study - Predicting Endoleaks Following Endovascular Aortic Aneurysm Repair Using 18F-Sodium Fluoride

Conditions
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Endoleak, Stent-Graft Endoleak, Abdominal Aortic Aneurysm

Intervention / Treatment
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* Diagnostic Test: 18F Sodium Fluoride Positron Emission Tomography / Computed Tomography
* Diagnostic Test: CT Aortic Angiogram
* Diagnostic Test: 12-month CT Aortic Angiogram
* Other: 24-month review


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: A diagnosis of AAA as defined by the European Society of Vascular Surgery guidelines on the management of aorto-iliac artery aneurysms, and having undergone endovascular repair within the recommended Instructions For Use (IFU) by the manufacturer. ['Endoleak' and 'No Endoleak groups only] Complication will be defined as any type of endoleak or stent graft migration ['Endoleak' group only]. A diagnosis of AAA requiring endovascular repair OR a diagnosis of juxtarenal AAA requiring fenestrated endovascular aneurysm repair as defined by the European Society of Vascular surgery guidelines on the management of aorto-iliac artery aneurysms and planned EVAR or fenestrated EVAR surgery. ['pre-EVAR' group only] Minimum age: 50 years. No maximum age. Retain capacity for informed consent Exclusion Criteria: The inability of patients to undergo PET/CT scanning Chronic kidney disease (eGFR ≤ 30 mL/min/1.73 m2) Major or untreated cancer Pregnancy Allergy or contra-indication to iodinated contrast Inability or unwillingness to give informed consent Life-expectancy of less than two years Known history of connective tissue disease

Ages Eligible for Study
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Minimum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Endoleak Group<br>Participants with a previous Endovascular Aneurysm Repair (EVAR) who have developed an endoleak | Diagnostic Test: 18F Sodium Fluoride Positron Emission Tomography / Computed Tomography<br>* PET scan using the 18F-Sodium Fluoride radiotracer followed by an attenuation correction CT scan<br>Diagnostic Test: CT Aortic Angiogram<br>* CT scan to assess aortic morphology and contextualise PET scan<br>|
| No Endoleak Group<br>Participants with a previous Endovascular Aneurysm Repair (EVAR) who have not developed an endoleak | Diagnostic Test: 18F Sodium Fluoride Positron Emission Tomography / Computed Tomography<br>* PET scan using the 18F-Sodium Fluoride radiotracer followed by an attenuation correction CT scan<br>Diagnostic Test: CT Aortic Angiogram<br>* CT scan to assess aortic morphology and contextualise PET scan<br>|
| Pre-EVAR Group<br>Participants who have an abdominal aortic aneurysm and who are undergoing an Endovascular Aneurysm Repair as standard of care | Diagnostic Test: 18F Sodium Fluoride Positron Emission Tomography / Computed Tomography<br>* PET scan using the 18F-Sodium Fluoride radiotracer followed by an attenuation correction CT scan<br>Diagnostic Test: 12-month CT Aortic Angiogram<br>* CT scan to assess aortic morphology and the stent graft<br>Other: 24-month review<br>* This will consist of a telephone consultation with the study participant and review of electronic clinical records<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Microcalcification activity in stented and aneurysmal aorta | Will be measured as 18F Sodium Fluoride binding in the aorta. Uptake will be quantified in Standardised Uptake Values and as a tissue to background ratios. | 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pattern of microcalcification activity in the stented aorta | Microcalcification activity | 12 months | 
| Intensity of microcalcification activity in the stented aorta | Microcalcification activity | 12 months | 
| Endoleaks | Computed tomography and ultrasound endpoints | 12 months | 
| Stent graft migration | Computed tomography and ultrasound endpoints | 12 months | 
| Aneurysm sac diameter | Computed tomography and ultrasound endpoints | 12 months | 
| Neck diameter and neck angulation | Computed tomography and ultrasound endpoints | 12 months | 
| Geometry: tortuosity, curvature, torsion | Computed tomography and ultrasound endpoints | 12 months | 
| Aneurysm-related mortality | Clinical endpoints | 24 months | 
| Re-intervention | Clinical endpoints | 24 months | 
| All-cause mortality | Clinical endpoints | 24 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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EVAR, Endoleak, 18F-Sodium Fluoride, PET