Plain English Summary
Background and study aims:
Peripheral arterial disease (PAD) is a common condition in which the blood flow to the legs is restricted. This happens because of the buildup of a fatty substance (plaque) on the walls of arteries. Over time this can cause the main arteries in the legs to become narrowed (stenosed) or blocked (occluded). As the arteries become narrower, patients begin the feel pain even when at rest and are at severe risk of developing ulcers or gangrene (acute lower limb ischaemia), which in severe cases can lead to amputation. For many patients, the only viable treatment option is to undergo surgery to restore blood flow. This is usually done using a procedure called an angioplasty (where a special balloon is inflated inside the affected artery to widen it) or an operation to bypass the blocked portion of the artery in the leg using a piece of another blood vessel. In some cases, arteries can become narrowed again after surgery (restenosis) however. A key challenge for blood vessel imaging is being able to predict restenosis in order to better understand the underlying biology and to allow tracking of the initial plaque's response to therapy. Work undertaken in Cambridge has shown that a type of imaging called positron emission tomography/computed tomography (PET/CT), which uses injectable radioactive dye, could be more accurate at tracking and monitoring plaques than standard techniques (involving ultrasound scans of blood vessels). The aim of this study is to look at examine the role of arterial inflammation and calcification both before and after a superficial femoral artery angioplasty.
Who can participate?
Men aged over 50 and women aged over 55 who are undergoing surgical treatment for PAD.
What does the study involve?
Participants who have an angioplasty scheduled are asked to attend the hospital twice prior to their surgery for scans. At each session, participants have their legs scanned with a PET/CT machine. They are given a small amount of tracer, inserted through a cannula (thing plastic tube) inserted into a vein. Participants also undergo a scan at the first session using an ultrasound (a scan that uses sound waves) to look at the blood flow of their legs. Participants then undergo their surgery. Six weeks after the surgery, the PET/CT scan is repeated. At 12 months after surgery, they undergo a final ultrasound scan.
What are the possible benefits and risks of participating?
There are no direct benefits with participating. There is a small risk of exposure to radiation due to the scans. There is a small and unlikely risks of allergic reaction or other side effects however the hospital has facilities to deal with this. Participant may experience discomfort when the cannula is placed into a vein, as well as bruising.
Where is the study run from?
Addenbrooke's Hospital (UK)
When is study starting and how long is it expected to run for?
November 2015 to October 2018
Who is funding the study?
British Heart Foundation (UK)
Who is the main contact?
Dr Mohammed Chowdhury
Dr Mohammed Chowdhury
Multi-modality imaging to determine the role of calcification and inflammation on restenosis rates following lower limb angioplasty: The CIRLA Study
Increased level of arterial wall inflammation and calcification predict restenosis risk following angioplasty of the superficial femoral artery.
The general aim of this project is to determine the role of arterial inflammation and calcification both pre- and post-intervention in risk of restenosis following superficial femoral artery angioplasty.
East of England - Cambridge East Research Ethics Committee, 10/09/2015, ref: 15/EE/0153
Observational cohort study
Primary study design
Secondary study design
Patient information sheet
See additional files
Peripheral Arterial Disease
Patients are identified from vascular clinic or vascular inpatient wards. As part of their usual clinical stream, participants are assessed and, if it is deemed appropriate, are scheduled to have a SFA angioplasty which is then booked.
Participants are then reviewed prior to this intervention and assessed for inclusion into the study (see inclusion/exclusion criteria). Eligible participants are approached and provided written information about the study. Participants are invited to the hospital on two separate days for a scanning session prior to the planned angioplasty. At each session the patient's legs will be scanned on a combined PET/CT machine. The scans will involve administration of a radioactive tracer. A cannula (thin plastic tube) will be inserted into the patient. The tracer will be injected through the cannula and the scans would be done 2 hours after the injection of the tracer. The technique is so sensitive that only a very tiny amount of the radioactive tracer is required. During the scan, patients are asked to lie flat on a bed on their back within the CT machine (which is shaped like a large doughnut). On the first of these days, patientsalso undergo an ultrasound scan of both legs to look at the blood flow through the arteries. Participants undergo their SFA angioplasty done to the standard level of care.
Six weeks after the angioplasty, participants return for their repeat PET-CT scans and are followed-up for 12 months thereafter. If participants undergo stenting at the time of angioplasty they are not invited back for the repeat PET-CT scan. At 12-months post angioplasty each participant have a final ultrasound duplex scan on completing the study.
Primary outcome measures
1. Primary patency, defined as SFA stenosis/anastamotic stenosis of < 50%, is measured using arterial duplex scanning at 12 months
2. FDG and NaF TBR measurements are measured using the scans at baseline and six weeks
3. Ankle-brachial pressure index bilaterally is measured using scanning at baseline
4. Blood markers and degree of disease are assessed using ultrasound duplex at baseline
5. Restenosis is measured using the ultrasound duplex at 12 months
Secondary outcome measures
Freedom from target lesion revascularization (TLR) at 1 year is measured by arterial duplex at 12 months.
Overall trial start date
Overall trial end date
Participant inclusion criteria
1. Aged 50 years or over (women aged 55 years or over)
2. Symptomatic peripheral arterial disease (intermittent claudication / critical limb ischaemia)
3. Undergoing superficial femoral artery angioplasty (PTA) or femoro-popliteal vein bypass graft (FPBG)
4. Patients with TASC A and B lesions for the PTA group (there will be no restriction with regard to disease severity on the FPBG group as long as the anastomosis is to the popliteal artery)
5. Taking standard antiplatelet/statin medication
Target number of participants
Participant exclusion criteria
1. Inability to undergo PET/CT
2. Presence of end stage renal failure
3. Metastatic malignancy
4. Patients undergoing adjunct endovascular procedures in the infrainguinal segments – PTA group only (e.g. Bare Metal Stent, Drug Eluting Balloon, Drug Eluting Stent)
5. Previous ipsilateral femoral artery angioplasty within the previous 6 months – PTA group only
6. Women under the age of 55 years
7. Patients with diabetes mellitus taking insulin
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Cambridge University Hospital Trust Hills Road
British Heart Foundation
Funding Body Type
private sector organisation
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Planned presentation at major cardiovascular meetings in the UK and USA, and publication in a major, high-impact, peer-reviewed cardiovascular journal.
IPD sharing statement:
The datasets generated during and/or analysed during the current study are/will be available upon request from Mr Mohammed Chowdhury (email@example.com)
Intention to publish date
Participant level data
Available on request
Results - basic reporting
- ISRCTN34690731_PIS_26Aug15_V3.docx Uploaded 15/08/2017