An interventional study of Iodinated contrast medium and CO2 automated injector contrast medium in Peripheral Arterial Disease, Chronic Kidney Diseases and Acute Kidney Injury, sponsored by University of Leicester. Active, not recruiting at 6 sites in United Kingdom. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-23.
Sponsored by University of Leicester · Not applicable, Interventional, and Prevention
This research trial will test whether using carbon dioxide as a contrast medium during surgery to open blocked leg arteries can prevent kidney injury. One in five people over 55 in the UK suffer with narrowing or blockages in their leg arteries, which is called peripheral arterial disease. It leads to poor leg circulation, which can cause leg gangrene or infection. Sometimes this may even lead to major lower limb amputation. To prevent this from happening, the affected arteries can be opened using endovascular revascularisation. These procedures are the most common artery surgeries in the NHS. To be able to perform these procedures, doctors use an iodine-based contrast medium (dye) injected in the artery, which can negatively affect kidney function.
Instead of the usual dye that causes kidney problems, carbon dioxide can be used as it does not damage the kidneys. No previous randomised controlled trial, however, has tested whether using carbon dioxide via automated injectors does indeed protect the kidneys in these procedures.
This research will take place in at least six NHS hospitals in the UK. People with peripheral arterial disease and chronic kidney disease who are having a procedure to open their arteries will be asked to take part. Participants will be randomly chosen to have the procedure with carbon dioxide or with standard iodine-based contrast medium. The investigators will then perform blood tests to measure serum creatinine on the 2nd, 30th, and 90th day after the procedure to compare kidney function between the two groups. The investigators will also compare the volume of iodine-based contrast medium used. The study will also include qualitative research into how the hospital staff performing the intervention feel, as well as how participants found the procedure with carbon dioxide.
Background and Rationale Peripheral arterial disease (PAD) frequently coexists with chronic kidney disease (CKD). Endovascular revascularisation, a common procedure for PAD, typically relies on iodine-based contrast medium, which is nephrotoxic and a known contributor to acute kidney injury (AKI). Patients developing AKI post-revascularisation face increased long-term major cardiovascular events, progression of CKD, and mortality. Using carbon dioxide (CO2) as an alternative contrast medium may mitigate this risk, as CO2 is not nephrotoxic. Automated intra-arterial CO2 injectors have recently been developed to address previous technical constraints associated with CO2 delivery, such as procedural pain and suboptimal imaging.
Trial Design and Methodology This research is a multicentre, prospective, open-label, parallel-group randomised controlled trial. The trial takes place across at least six UK NHS hospitals providing specialist care for PAD. Following informed consent, participants are randomised via a centralised web-based system in a 1:1 ratio within 15 days of consent. Randomisation is minimised by baseline CKD stage, age, presence of tissue loss, and diabetes. The study intends to recruit 174 participants to achieve 90% power to detect a clinically meaningful difference in serum creatinine values, accounting for a 10% participant drop-out rate.
Procedural Details All pre- and post-procedure care remains identical for both the intervention and control groups, adhering to existing NHS PAD care pathways and National Institute of Health and Care Excellence (NICE) guidance, which includes standard oral and intravenous fluid therapy. The investigators will monitor renal function by recording serum creatinine levels at baseline and at 2, 30, and 90 days post-procedure. Follow-up assessments will take place either in-person at the vascular clinic or via telephone until day 90.
Qualitative and Health Economic Evaluations The trial incorporates a health economic evaluation to assess the cost-effectiveness of the automated CO2 injector from an NHS and societal perspective. This evaluation utilises intraprocedural data, healthcare resource usage data, and Quality of Life (QoL) assessments collected via validated questionnaires at 90 days post-procedure.
Additionally, a qualitative and implementation sub-study will be conducted to explore acceptability and implementation factors. A purposively selected subgroup of up to 12 participants receiving the CO2 automated injector, alongside up to 20 involved healthcare practitioners, will complete semi-structured interviews guided by the Theoretical Framework of Acceptability (TFA). Bespoke questionnaires will also be administered to practitioners to evaluate the feasibility, appropriateness, and innovation-specific implementation intentions associated with the technology.
1,573 studies on the registry are indexed under Peripheral Arterial Disease; 284 are open to participants now.
This study's enrollment of 184 is above the median of 73 across 1,078 interventional studies indexed under Peripheral Arterial Disease.
Browse Peripheral Arterial Disease studies →University of Leicester is the lead sponsor of 170 studies on the registry; 51 are open to participants now.
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Exclusion Criteria:
Standard of care
Other: Iodinated contrast medium
CO2 automated injector
Other: CO2 automated injector contrast medium
Standard of care iodinated contrast medium used by NHS trusts across the UK for endovascular revascularisation.
Carbon dioxide via an automated injector contrast medium
Also known as: Angiodroid
Renal Function: Log Serum Creatinine
Assessment of short and medium-term renal decline by measuring serum creatinine from blood samples processed at local pathology laboratories. Unit of Measure: log(µmol/L). Renal decline or "worsening of kidney function" is defined as a \>25% decline in the estimated Glomerular Filtration Rate (eGFR) from the baseline assessment. The baseline eGFR is defined as the most recent value recorded prior to the procedure. Additionally, the trial measures short and medium-term renal decline by tracking changes in Log serum creatinine at 2, 30, and 90 days post-procedure, and evaluates the onset of Acute Kidney Injury (AKI) based on the KDIGO criteria.
Time frame: 2, 30, and 90 days after endovascular revascularisation
Volume of iodinated contrast medium used
Measurement of the overall volume of iodinated contrast medium required to complete the endovascular revascularisation procedure. Unit of Measure: Milliliters (ml)
Time frame: Intraoperative (during the index procedure)
Incidence of Acute Kidney Injury (AKI)
Assessment of the development of acute kidney injury evaluated using the Kidney Disease Improving Global Outcomes (KDIGO) criteria. Unit of Measure: Percentage (%) of participants
Time frame: Within 2 days (48 hours) of the procedure
Proportion of participants developing Major Adverse Kidney Events (MAKE)
The development of a major adverse kidney event, defined as either death, new requirement for dialysis, or worsening kidney function indicated by a \>25% decline in estimated Glomerular Filtration Rate (eGFR) from baseline. Unit of Measure: Percentage (%) of participants
Time frame: By 90 day post index procedure follow-up
Inpatient stay duration
The length of time the participant spent as an inpatient since randomisation. Unit of Measure: Days
Time frame: By 90 day post index procedure follow-up
Pain experienced during the procedure
Assessment of the pain experienced by the participant during the injection of the contrast medium, measured using a Visual Analogue Scale (VAS). The scale ranges from 0 to 10, where 0 indicates no pain and 10 indicates the worst possible pain. Unit of Measure: Score on a scale from 0 to 10
Time frame: During the index procedure (measured at the first and final angiogram)
Quality of Life: EQ-5D-5L
Assessment of health-related quality of life measured using the EuroQOL 5D 5L (EQ-5D-5L) Questionnaire. It assesses 5 dimensions on a 1-5 scale and includes a visual analogue scale rating current health from 0 (worst) to 100 (best). Unit of Measure: Score on a scale from 0 to 100
Time frame: Baseline and 90 days post-procedure
Quality of Life: SF-36
Assessment of health-related quality of life measured using the 36-Item Short Form Health Survey (SF-36) Questionnaire, which covers eight domains of health converted into a total score indicating low to high quality of life. Unit of Measure: Total score
Time frame: Time Frame: Baseline and 90 days post-procedure
Planned Revascularisation Completion Rate
Evaluation of the technical success of the intervention by calculating the proportion of endovascular revascularisation procedures that were completed as originally planned. Unit of Measure: Percentage (%) of participants
Time frame: Intraoperative (during the index procedure)
Number of Re-interventions
Tracking the total number of subsequent surgical or endovascular re-interventions required. Unit of Measure: Number of interventions
Time frame: By 90 day post index procedure follow-up
Participant Intervention Acceptability
Evaluation of the acceptability of receiving carbon dioxide via the automated injector, assessed using a self-reported 8-item Theoretical Framework of Acceptability (TFA) Questionnaire. Higher scores indicate a higher level of acceptability. Unit of Measure: Score from 8 to 40
Time frame: By 90 day post index procedure follow-up
Procedure Associated Costs
A micro-costing health economic analysis calculating the costs associated with the procedure, including equipment, staff, hospital stays, and community services. Cost in Great British Pounds (£)
Time frame: By 90 day post index procedure follow-up
Plan to share: No
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Ran from Feb 2025 to primary completion in Oct 2026, 19 months.
Of 276 non-industry interventional studies with no phase under Peripheral Arterial Disease, half reached primary completion within 33 months of starting (the median), counting those still running; a quarter within 17 and three quarters within 63. This study's 19 months is below that.
Counting every sponsor, half of 401 studies reached it within 31 months; a quarter within 17 and three quarters within 53.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is active, not recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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