The Department of Vascular, Endovascular and Transplant Surgery has a strong track record in leading and publishing clinically-driven and translational research, and collaborating with national and international partners to address contemporary challenges in vascular surgery from basic science through to leading randomized controlled trials.
Our research focuses on understanding disease mechanisms, improving patient outcomes, and applying new technologies to improve surgical care – always with a focus on improving outcomes for our patients.
Key research themes
Here’s a snapshot of some of our current research themes and major projects.
Decision making and Quality of Life measures for patients facing dialysis
The demand for dialysis services is increasing nationally, presenting distinct challenges for patients and those involved in their care. It is anticipated that a growing number of patients will require haemodialysis via a venous catheter or arteriovenous fistula in the coming years. Ensuring that patients are adequately informed about available treatment options and the anticipated clinical pathway is therefore increasingly important.
In collaboration with our renal–vascular multidisciplinary team, we maintain strong links with academic renal colleagues.
One example of this collaborative work is our participation in research led by Dr Katherine Richards focused on the development of a patient led decision-support tool to inform haemodialysis initiation.
Ongoing research is examining health related quality of life among older patients requiring dialysis, with the aim of better informing holistic, patient centred decision making.
Primary contact:
Dr Ruth Benson
Department of Surgery and Critical Care (Christchurch)
International women’s small aneurysm trial (WARRIORS)
Early endovascular repair vs standard care for women with an abdominal aortic aneurysm
An abdominal aortic aneurysm (AAA) is a weakening and expansion of the main abdominal blood vessel. The risk of rupture, which is typically fatal, increases with the size of the aneurysm. The presence of a AAA is associated with very high risk of future cardiovascular events (stroke, myocardial infarction).
This research aims to reduce inequity in abdominal aortic aneurysm care and improve the survival and quality of life of women, particularly wāhine Māori, with AAA. We hypothesise that lowering the size threshold for AAA repair for women, whilst addressing cardiovascular risk, will prevent AAA rupture and save lives, and reduce inequity between Māori and non-Māori. Importantly, women currently have four times greater risk (than men) of rupture of a small (“sub-treatment threshold”) aneurysm. In New Zealand, despite the overall prevalence of AAA being lower in women than in men, 1 in 3 people with ruptured AAA are women. 80% of those women with a ruptured AAA do not receive any emergency repair (i.e. are palliated).
The trial is strongly supported by clinicians and women with AAA in Aotearoa New Zealand, and internationally. This is an investigator-initiated, pragmatic, international, comparative effectiveness randomized controlled trial of early elective keyhole AAA repair (EVAR) versus ‘current gold standard’ care in women with small asymptomatic AAA who are eligible for EVAR, nested within a cohort study.
All participants will be followed for clinical outcomes, quality of life, and AAA-related anxiety. Dr Lyons is the national lead investigator for this trial in New Zealand, in collaboration with Prof Sue Crengle. In New Zealand the trial is funded by the Health Research Council. Dr Lyons and Professor Crengle are leading an international frailty substudy.
Abdominal aortic aneurysm in women in Aotearoa New Zealand. NZMJ Vol. 138 No. 1627 12 December, 2025
DOI: 10.26635/6965.7028
Primary contacts:
Dr Oliver Lyons
Department of Surgery and Critical Care (Christchurch)
Dr Ruth Benson
Department of Surgery and Critical Care (Christchurch)
Measurement of antioxidants and damaged biological molecules in atherosclerotic plaque
An estimated eight carotid endarterectomies are required to prevent one stroke in symptomatic patients with severe carotid artery stenosis whereas 30 carotid endarterectomies are required to prevent one stroke in asymptomatic patients.
In collaboration with Dr Stephen Gieseg and his team at the University of Canterbury, we are analyzing carotid plaques alongside blood and urine using the MARS SPCCT and biochemical assays to characterise morphological and chemical components of the atheroma.
The goal is to create parameters to distinguish unstable plaques from stable ones pre-emptively.
https://doi.org/10.1515/pteridines-2025-0055
Primary contact:
Dr Ruth Benson
Department of Surgery and Critical Care (Christchurch)
Metformin Aneurysm Trial
Canterbury is a recruiting centre for this international randomized controlled trial, which will find out whether the diabetes drug Metformin avoids the need for surgical repair or aneurysm rupture and save lives.
In New Zealand this trial is funded by the HRC and is led by Prof Greg Jones (University of Otago, Dunedin).
Primary contact:
Dr Oliver Lyons
Department of Surgery and Critical Care (Christchurch)
Novel biomarkers in peripheral artery disease
In collaboration with Professor Greg Jones (University of Otago, Dunedin), this HRC-funded prospective observational study will assess the utility of a novel biomarker of smoke exposure as a predictor of cardiovascular outcomes. Two hundred patients with intermittent claudication due to peripheral artery disease will be followed over five years.
Primary contact:
Dr Oliver Lyons
Department of Surgery and Critical Care (Christchurch)
Novel bioresorbable stents
We were one of the first centres globally to enroll patients into the Efemoral I study.
This is a trial of a novel bioresorbable, drug eluting stent, for the treatment of patients with symptomatic stenosis or occlusion of their femoropopliteal artery. With forecast rates of symptomatic cases set to rise, estimates suggest disability-adjusted life years will rise from 19.7 to 33.1 per 100,000 globally.
Finding safer, more effective treatments for those struggling with claudication in their daily life is a priority.
https://www.jacc.org/doi/abs/10.1016/j.jacc.2025.09.1088
Primary contact:
Dr Ruth Benson
Department of Surgery and Critical Care (Christchurch)
Stroke prevention in thoracic surgery
Keyhole repair of the major blood vessel in the chest (the 'aorta') is done to prevent death from the blood vessel bursting, for example due to an 'aortic aneurysm' or 'aortic dissection'. Unfortunately, the operation has an unavoidable small risk of stroke, and also ‘silent stroke’. These patients may suffer with decline in brain function and delirium, but the long-term detrimental effects of silent strokes are unclear. We think these silent strokes are mostly caused by tiny air bubbles trapped within the fabric of the stents used for the keyhole operation.
In this trial, we will evaluate whether flushing the stents with carbon dioxide gas and then liquid (prior to insertion in the patient) will be better at removing the trapped air bubbles than just using liquid alone (which is current standard practice), and reduce the number of silent strokes (and associated mental decline) that patients suffer. This trial may provide a cheap and readily useable method of reducing the risk of stroke in these patients.
This is an international trial, with centres in the UK, USA and Christchurch, New Zealand. In New Zealand, the trial is funded by Canterbury Medical Research Foundation.
Primary contact:
Dr Oliver Lyons
Department of Surgery and Critical Care (Christchurch)
Sympathetic nerve activity and blood pressure in acute aortic dissection
Control of blood pressure following acute type B aortic dissection usually requires sympatholytic antihypertensive medication. Although sympathetic nerve activity is central to blood pressure control, its role in the hypertensive response to acute aortic dissection has not been assessed.
This study will quantify muscle sympathetic nerve activity and plasma catecholamine levels in patients with acute aortic dissection.
Primary contact:
Dr Adib Khanafer
Vascular Surgery Department, Health New Zealand, Canterbury (Te Whatu Ora, Waitaha)
Email adib.khanafer@cdhb.health.nz
Vascular disease in an ageing population
Age is a major risk factor for the development of comorbidities associated with many conditions managed by vascular surgeons. Although a range of clinical risk scores and quality of life measures already exist, current research is increasingly focused on evaluating the applicability of established scoring systems developed for related constructs—such as frailty—within the vascular surgery population.
Presented and published work in this area includes the assessment of osteoporosis risk scores as predictors of discharge destination following major vascular surgery. Future work will focus on other areas including outcomes for our end stage renal failure cohort.
ANZ J Surg. 2026 Jan;96(1-2):185-191.
Doi: 10.1111/ans.70444
Primary contact:
Dr Ruth Benson
Department of Surgery and Critical Care (Christchurch)
Vascular Graft and Endograft Infection
Current research interests include the development and application of novel outcome classifications to improve registry and trial design, the utility of 18F-F FDG PETCT in the diagnosis of vascular graft and endograft infection, and the microbiology of graft infection. The department is engaged in basic science and clinical research with collaborations within New Zealand and internationally.
Primary contact:
Dr Oliver Lyons
Department of Surgery and Critical Care (Christchurch)
Other vascular surgery research
Our Department also undertakes a wide range of vascular surgery research, including quality-of-life outcomes, perioperative care, novel surgical techniques, and addresses broader health system questions.
Our department collaborates with multiple groups across New Zealand (including at the University of Canterbury, and Auckland), and in the USA, Europe, Asia and Australasia.
Major recent and ongoing activities include:
- COVIDSURG and COVER
- PREDICT
- DEFINITE
- CROCS BKA
Primary contacts:
Dr Oliver Lyons
Department of Surgery and Critical Care (Christchurch)
Dr Ruth Benson
Department of Surgery and Critical Care (Christchurch)
Research opportunities, Future Health Researchers, MMedSc, PhD
The Department regularly supports junior colleagues through departmental audits, and at least one Future Health Researcher project per year.
For more information, contact:
Dr Oliver Lyons
Email oliver.lyons@otago.ac.nz
Dr Ruth Benson
Email ruth.benson@otago.ac.nz