ELATE is a 2-year NIHR-funded project aiming to evaluate the effectiveness and cost effectiveness of the use of Local Anaesthesia in the endovascular repair of ruptured abdominal aortic aneurysms (rAAA).
ELATE will use the information routinely recorded as part of NHS patient care to study the comparative clinical and cost effectiveness of local versus general anaesthetic when undergoing endovascular repair (EVAR) of ruptured abdominal aortic aneurysm (AAA). We will evaluate the clinical and cost-effectiveness using study designs and statistical techniques seek to emulate a clinical trial.
The ELATE study aims to evaluate the effectiveness and cost-effectiveness of local versus general anaesthesia for endovascular repair (EVAR) of ruptured abdominal aortic aneurysm (rAAA).
Ruptured abdominal aortic aneurysm (rAAA) is almost always fatal without emergency intervention by open surgery or minimally invasive endovascular repair (EVAR). NICE recommend EVAR rather than open repair for rAAA, noting that EVAR provides more benefit than open surgical repair for most people, especially men over 70 and women of any age. This recommendation is based on results from the IMPROVE (Immediate Management of the Patient with Rupture: Open Versus Endovascular repair) trial that compared EVAR with open repair. However, outcomes from emergency EVAR remain poor; around 20% of people die in hospital3 and 40% within one year.
There is considerable variation across UK centres in the use of local versus general anaesthesia in rAAA, with a median of 40% using local anaesthesia but with an inter-quartile range of 23-60%. This variation highlights that for patient having EVAR of rAAA, use of either local or general anaesthesia is likely to depend on the preference of the local clinical team as well as the clinical characteristics of the patient.
Our study will provide rigorous evidence on the relative effectiveness and cost-effectiveness of alternative anaesthetic approaches both overall, and for specific patient subgroups.
This section provides more detailed information about the study design for researchers.
Research question:
How effective and cost-effective is local infiltrative anaesthesia versus general anaesthesia for endovascular repair of ruptured abdominal aortic aneurisms (rAAA)?
Background:
For people who have surgery for rAAA, outcomes are poor; even after endovascular surgery 40% die within one year. NICE recommend that surgeons ‘consider’ local anaesthesia for endovascular repair of rAAA. However, no rigorous evidence exists to inform this decision. There is wide variation in the type of anaesthesia used across vascular centres in the UK. An RCT to address this question is likely to be impractical and unethical. Consequently, evidence from observational studies is required. A target trial emulates a hypothetical pragmatic RCT for assessing comparative effectiveness using observational data.
Aims and objectives:
To evaluate the effectiveness and cost-effectiveness of local versus general anaesthesia for endovascular repair (EVAR) of rAAA. The objectives are:
1. To assess the effectiveness and cost-effectiveness of local versus general anaesthesia for EVAR of rAAA.
2. To assess the effectiveness and cost-effectiveness of local versus general anaesthesia in patient subgroups (e.g. sex, frailty).
3. To provide recommendations on the choice of anaesthesia according to patient subgroup.
Methods:
We will provide timely, rigorous evidence on the effectiveness and cost-effectiveness of local versus general anaesthesia for EVAR of rAAA. Our target trial will use observational data from the National Vascular Registry (NVR). It will apply criteria to define the study populations, intervention and comparator strategies and outcomes of direct relevance to clinical decision-making. Criteria will be informed by panels of clinicians and patients/public representatives. Based on advice from patients and clinicians, the primary outcome will be 30-day mortality. Secondary outcomes will include days alive and out of hospital.
We will use an instrumental variable analysis based on the approach we used in a previous NIHR-funded study (ESORT). This approach can provide accurate estimates of treatment effectiveness, even when there are unmeasured differences between the intervention and comparator groups. The cost-effectiveness analyses will be based on resource use and mortality data from the NVR linked to Hospital Episode Statistics and mortality data. We will report relative effectiveness and cost-effectiveness according to pre-specified patient subgroups. We will provide recommendations on which mode of anaesthesia is likely to be effective and cost-effective for each subgroup.
To help ensure this study generates evidence that directly meets the needs of decision-makers, we will convene panels of clinicians, patient/public representatives, and other stakeholders at the study outset. These groups will help translate results to directly inform clinical decision-making including updates to clinical guidelines for rAAA.
Anticipated impact and translation:
Our clinical and patient/public panels and ‘all stakeholder event’ will help ensure the research is directly relevant to the NHS. Our clinical co-applicants and steering committee will help translate findings to national decision-makers. This study will exemplify how timely input from key stakeholders can help ensure a target trial directly informs clinical practice.
What is PPI?
PPI means ‘Patient and Public Involvement’ and is a core component of our research. It helps us to ensure that our researchers are asking the right questions and using the right methods, so that our studies will provide answers that will make a real difference to people’s lives.
If you would like to know more about PPI, this video explains more about the value of involving patients and the public in research. It is made by our funders, National Institute for Health Research (NIHR). You can read more about patient and public involvement in research on the NIHR/INVOLVE website.
PPI in the ELATE study
We will convene two ‘design’ and two ‘translation’ PPIE workshops, and one PPIE engagement workshop on ‘routine data’. In the ‘design’ workshops we will ask for patient and public views about the outcome measures that will be available, such as the number of days in hospital. These insights will help us finalise the study protocol. In the ‘routine data’ workshop we will outline how these data are used to answer the study question. We will discuss concerns participants may have about data privacy. In the translation workshops participants will help us make the study findings widely accessible to lay audiences, and to identify priorities for future research from the patient and public perspective.
LSHTM Team
- Assistant Professor Patrick Bidulka – co-PI
- Professor Richard Grieve
- Stephen O’Neill
- Daniel Mongiardi
North Bristol NHS Trust
- Professor Robert Hinchliffe – Professor of Vascular Surgery – co-PI
University of Warwick
- Dr Joyce Yeung
University of Bristol
- Professor Ronelle Mouton
PPI Representatives
- Paul Charlton
- Roland Keedwell
The ELATE study will use de-identified patient information from the National Vascular Registry and the NHS to try to improve vascular surgery for patients and reduce costs to the NHS. The data that will be used for the ELATE study are already collected as part of routine patient care.
The ELATE study team has applied to the NHS Research Ethics Committee and the Confidentiality Advisory Group for permissions to use these de-identified data for research. Once approvals are in place, we will work with data managers trained in data protection and security at the National Vascular Registry and at NHS England to securely deliver de-identified patient information to the ELATE study team at the London School of Hygiene & Tropical Medicine.
The ELATE study will include people who have had emergency surgery to repair a ruptured abdominal aortic aneurysm (the major blood vessel in the abdomen) between 1 January 2014 to 31 December 2024. The ELATE research team will receive de-identified patient information from the National Vascular Registry and NHS England to conduct the study. The ELATE research team will also receive the death date from NHS England for those people who died during the study period. The death date will be deleted as soon as possible by the ELATE research team so that only de-identified data are stored on the secure servers at the London School of Hygiene & Tropical Medicine.
The ELATE study will not include anyone who has opted out of their data being used for research through the National Data Opt-Out.
If you had an emergency surgery to repair a ruptured abdominal aortic aneurysm between 1 January 2014 to 31 December 2024 and you do not want to opt-out via the National Data Opt-Out, but you do want to opt-out of the ELATE study in particular, please contact the National Vascular Registry who can manage this request. View the contact information.
More information can be found in the ELATE study patient information sheet.