Peripheral arterial disease (PAD) commonly coexists with chronic kidney disease (CKD). Patients with symptomatic PAD often require endovascular revascularisation to relieve pain or salvage limbs. However, the iodinated intra-arterial contrast routinely used in these procedures is nephrotoxic, placing patients with CKD at increased risk of acute kidney injury (AKI) and long-term renal decline. Carbon dioxide (CO₂) delivered via automated injection is a potential alternative imaging contrast medium. This trial will evaluate whether using CO₂ instead of iodinated contrast reduces the risk of AKI and short-term renal function decline in this high-risk group.

This is a multicentre, open-label, prospective randomised controlled trial across six secondary-care National Health Service (NHS) vascular surgery centres. A total of 174 patients with PAD and CKD undergoing endovascular intervention will be randomised 1:1 to receive iodinated contrast (standard of care) or CO₂ via automated injector (Angiodroid). All perioperative care will follow local NHS protocols.

The primary outcome is log serum creatinine at 2, 30 and 90 days postprocedure. Key secondary outcomes include: incidence and severity of AKI within 48 hours postprocedure, major adverse kidney events (death, dialysis or >25% estimated glomerular filtration rate decline) by 90 days, inpatient length of stay, procedural pain, quality of life, procedural success, reinterventions, acceptability and feasibility (patient/practitioner questionnaires) of using CO₂, and cost-effectiveness (healthcare resource use analysis). A mixed-methods process evaluation will be undertaken with patients and clinicians.

The trial has been approved by an NHS ethical review committee (24/WA/0332) and patients have been involved in trial design. Findings will be disseminated to participants, clinicians and the wider public through patient groups, lay summaries, social media, conferences, peer-reviewed journals and NHS policy channels.

ISRCTN23564393.

Severe aorto-iliac steno-occlusive atherosclerotic disease is a major cause of morbidity and amputation in patients with peripheral arterial disease. While both open surgical and endovascular revascularisation are standard treatments in this patient group, there is no high-quality randomised evidence to determine which approach offers superior clinical and cost-effectiveness, leading to uncertainty and poor outcomes after intervention.

The EVOCC trial is a national, multicentre, parallel-group, superiority randomised controlled trial comparing open surgery to endovascular revascularisation in patients with symptomatic severe aorto-iliac occlusive disease. A total of 628 participants across 30 NHS sites in the UK will be randomised 1:1 to receive either open surgery or endovascular (minimally invasive) intervention. The primary outcome is amputation-free survival, defined as time to first event (major lower limb amputation or death). Secondary outcomes include mortality, cardiovascular events, hospital readmissions, re-interventions and quality-of-life measures. An internal pilot phase (10 sites, 6-month duration) will assess recruitment feasibility. A QuinteT Recruitment Intervention is integrated into the trial to optimise recruitment.

The trial has received ethical approval from a UK Research Ethics Committee (REC reference: 23/SW/0065; trial registration reference: ISRCTN14591444). Informed consent will be obtained from all participants.

The EVOCC trial is the first RCT assessing the clinical and cost-effectiveness of open vs endovascular revascularisation for severe aorto-iliac disease worldwide. The results will provide robust evidence to inform clinical practice and healthcare policies globally. Results will be disseminated via patient groups, online lay summaries, a trial website, social media, presentations in conferences, a formal scientific publication in a medical journal and direct communications with policymakers across borders.

ISRCTN14591444.

Endovascular aortic aneurysm repair (EVAR) requires long-term surveillance to detect and treat postoperative complications. However, prediction models to optimise follow-up strategies are still lacking. The primary objective of this study is to develop predictive models of post-operative outcomes following elective EVAR using Artificial Intelligence (AI)-driven analysis. The secondary objective is to investigate morphological aortic changes following EVAR.

This international, multicentre, observational study will retrospectively include 500 patients who underwent elective EVAR. Primary outcomes are EVAR postoperative complications including deaths, re-interventions, endoleaks, limb occlusion and stent-graft migration occurring within 1 year and at mid-term follow-up (1 to 3 years). Secondary outcomes are aortic anatomical changes. Morphological changes following EVAR will be analysed and compared based on preoperative and postoperative CT angiography (CTA) images (within 1 to 12 months, and at the last follow-up) using the AI-based software PRAEVAorta 2 (Nurea). Deep learning algorithms will be applied to stratify the risk of postoperative outcomes into low or high-risk categories. The training and testing dataset will be respectively composed of 70% and 30% of the cohort.

The study protocol is designed to ensure that the sponsor and the investigators comply with the principles of the Declaration of Helsinki and the ICH E6 good clinical practice guideline. The study has been approved by the ethics committee of the University Hospital of Patras (Patras, Greece) under the number 492/05.12.2024. The results of the study will be presented at relevant national and international conferences and submitted for publication to peer-review journals.