Effectiveness of intensive care for patients undergoing vascular surgery in the United Kingdom

University of Bristol (UoB) requires access to NHS England data for the purpose of the following research project:

Effectiveness of intensive care for patients undergoing vascular surgery in the United Kingdom

The following is a summary of the aims of the research project provided by University of Bristol:

Peripheral arterial disease (PAD) and diabetes-related complications lead to over 12,000 vascular surgeries annually in the UK, including high-risk procedures such as carotid and lower limb operations. Many patients undergoing these surgeries are frail and medically complex, resulting in a high incidence of postoperative complications, hospital readmissions, and mortality; particularly among those requiring urgent or emergency surgery. Despite improvements in care through centralisation and quality initiatives, 30-day mortality rates remain significant (6.4%–8.3%). Emergency procedures, which now account for nearly 46% to 82% of all vascular surgeries, often limit opportunities for medical treatments to ensure patients are as fit as possible before the operation and are consequently associated with significant costs, resource utilisation, and need for care in the intensive care unit [ICU] or high dependency unit [HDU]).

ICUs provide critical support for managing severe postoperative complications, but not all patients benefit equally from ICU admission. Some studies suggest ICU interventions improve outcomes for high-risk patients, while others show no benefit or even worse outcomes compared to standard ward care. Given the UK's limited ICU capacity; among the lowest in Europe; there is an urgent need to optimise ICU resource allocation. Identifying which patients truly require ICU care versus those who can safely recover on a ward is essential to improving outcomes and reducing surgical delays and cancellations.

This research priority has been formally recognised by several national initiatives, including the “Getting It Right First Time” programme in vascular surgery and intensive care, the National Confidential Enquiry into Patient Outcome and Death (NCEPOD), and the NIHR James Lind Alliance (JLA) priority setting partnerships. It has been identified as a top research priority in intensive care, and among the top ten in anaesthesia and perioperative care, with significant input from patients and the public. Furthermore, the proposed research aligns with national efforts to improve perioperative outcomes for patients with peripheral arterial disease (PAD) and those undergoing amputation and supports the NICE strategic objective of leveraging real-world data to address critical evidence gaps in perioperative care.

Aims of the research are:

• To examine the current landscape and trends in intensive care use for patients undergoing vascular surgery for blood vessel narrowing or blockages in the neck and legs between 2014 and 2024.

• Evaluate data on patients’ characteristics (for example, their age, sex, and past medical history), the operation they received and details (for example, the complexity of the operation and severity of disease), whether they went to intensive care or a normal ward after surgery, whether admission to intensive care was planned before they had the surgery.

• Evaluate the impact of ICU admission on postoperative outcomes including complications, mortality, and readmissions in patients undergoing vascular surgery.

• To compare outcomes between patients admitted to intensive care and those admitted to a normal ward after surgery.

• Identify patient groups more likely to be admitted to ICU and factors influencing ICU admission decisions.

• Analyse healthcare resource utilisation, including costs, ICU/HDU stays, and hospital length of stay.

• To understand the decision-making process behind intensive care admissions following vascular surgery and to support evidence-based decision-making to optimise ICU resource allocation and improve patient outcomes

• Contribute to national research priorities in perioperative care and inform NHS policy using real-world data.

• Assess variation in ICU admission practices across different hospitals.

The following NHS England Data will be accessed:

• Hospital Episode Statistics Admitted Patient Care (HES APC) - necessary to capture readmission (whether this is related to the original operation or complications of the operation)

• Civil Registrations of Death - necessary to obtain details on long-term survival and cause of death (whether this is related to their vascular disease).

Additionally, these datasets are necessary to obtain further demographic data which are not readily available in other registries. Furthermore, the date of death field is essential for calculating the number of survival days from the date of the original operation. This information will be permanently destroyed once the data has been processed and the survival duration has been derived.

The level of the Data will be:

• Identifiable – necessary because although the University of Bristol will hold no identifiable data, the technical risk of reidentification exists.

The Data will be minimised as follows:

• Limited to adults aged >18 years undergoing infrainguinal lower limb bypass or major lower limb amputation or carotid endarterectomy.

• Limited to date of procedure between 1/1/2014 to 31/12/2024.

• Limited to hybrid procedures with concomitant endovascular intervention in addition to surgical bypass or major lower limb amputation.

University of Bristol is the research sponsor and the controller as the organisation responsible for ensuring that the Data will only be processed for the purpose described above.

National Vascular Registry (NVR) is owned by the Healthcare Quality Improvement Partnership (HQIP) and maintained by the Royal College of Surgeons (RCS).

The lawful basis for processing personal data under the UK GDPR is:

Article 6(1)(e) - processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the controller;

The lawful basis for processing special category data under the UK GDPR is:

Article 9(2)(i) processing is necessary for reasons of public interest in the area of public health and is carried out by or under the responsibility of a health professional.

This research is being carried out by healthcare professionals and addresses important areas of public interest in the area of public health. This is demonstrated by an expressed need for research in intensive care usage in surgery nationally in the UK, due to a lack of detailed national guidelines to inform selection of patients for intensive care.

The funding is provided by National Institute for Health and Care Research (NIHR).

The funding is specifically for the study described. Funding is in place until October 2028

A professor of Anaesthesia and Consultant Anaesthetist at the North Bristol Trust and a professor of Health Economics at the London School of Hygiene and Tropical Medicine have a supervisory role in the methodology and conduct of research. They will not be involved in data analysis or data processing.

Only the University of Bristol will have access to the NHS data disseminated under this Data Sharing Agreement (DSA).

The study was designed with clinical and statistical experts, as well as input from patients and the public. This includes Professors who have provided clinical expertise and collaborative links to national societies in vascular surgery, intensive care, and anaesthesia, including causal inference methodology, target trial emulation, and health informatics, providing oversight and support for the statistical methodology required for this project. The Bristol Vascular Patient Advisory Group (PAG) and Royal College of Anaesthesia (RCoA) Patients, Carers, and Public group (PCPIE) were approached for input on the study design and protocol. Both groups include patients with lived experience of vascular surgery or intensive care and have experience advising on previous NIHR-funded studies, and provision of services documents with the Vascular Societies’ of Great Britain and Ireland.

NVR will transfer data to NHS England. The data will consist of identifying details (specifically NHS Number, Date of Birth, and a unique person ID) for the cohort to be linked with NHS England data.

NHS England will provide the relevant records from the HES APC and Civil Registrations of Death to University of Bristol.

The Data will contain no direct identifying data items but will contain a unique person ID which can be used to link the Data with other record level data already held by the recipient.

The Data will not be transferred to any other location.

The Data will be stored on servers at university of Bristol.

The Data will be accessed onsite at the premises of University of Bristol and by authorised personnel via remote access.

The University of Bristol must confirm and provide evidence upon audit by NHS England that access via any remote device complies with the data security obligations within this DSA and the Data Sharing Framework Contract.

For remote access:

- Remote access will only be from secure locations situated within the territory of use (as further restricted elsewhere within the DSA if so done) stated within this DSA;

- Access controls granting users the minimum level of access required are in place;

- Remote access is only via secure connections (e.g., VPNs or secure protocols) to protect data;

- Multifactor authentication (MFA) is required for remote access;

- Device security, including up-to-date software and operating systems, antivirus software, and enabled firewalls are utilised for the remote access;

- All remote access is undertaken within the scope of the organisation’s DSPT (or other security arrangements as per this DSA) and complies with the organisation’s remote access policy.

The above applies in addition to any condition set out elsewhere within the DSA (e.g. who may carry out processing, and for what purpose).

Remote processing will be from secure locations within England/Wales.

The data will not leave England/Wales at any time.

Access is restricted to employees of University of Bristol who have authorisation from the Principal Investigator.

All personnel accessing the Data have been appropriately trained in data protection and confidentiality.

Data will be linked at person record level with pseudonymised clinical data provided by the NVR and the Intensive Care National Audit and Research Centre (ICNARC), both of which will contain the same study ID shared with NHS England by the NVR.

Although the University of Bristol will hold no identifiable data, the technical risk of reidentification exists.

There will be no requirement and no attempt to reidentify individuals when using the pseudonymised dataset.

Analysts/researchers from the University of Bristol will process the Data for the purposes described above.

The expected outputs of the processing will be:

• A report of findings to key organisations and stakeholder groups (e.g. RCoA, the Royal College of Surgeons of England and VSGBI Specialist Interest Groups) for future clinical guideline development.

• Submissions to peer reviewed journals peer-review journals (e.g. Anaesthesia, British Journal of Surgery, European Journal of Vascular and Endovascular Surgery).

• Presentations at national and international vascular and anaesthesia meetings (e.g. VSGBI Annual Scientific Meeting, European Society of Vascular Surgery Meeting, Vascular Anaesthesia Society of Great Britain and Ireland Annual Scientific Meeting).

The outputs will not contain NHS England Data and will only contain aggregated information with small numbers suppressed as appropriate in line with the relevant disclosure rules for the dataset(s) from which the information was derived.

The outputs will be communicated to relevant recipients through the following dissemination channels:

• Publication of findings on University of Bristol's website

• Workshops involving patients and public through regional and national patient networks. There will be collaboration with national bodies (e.g. the RCoA PCPIE and Vascular Specialist Interest Groups) to provide patient information resources. Patients will be encouraged to provide their input on the result dissemination process by attending the PPI meetings and approve any public information.

The following are target dates for production and dissemination of the outputs:

• Conference presentations – November 2027,2028 (likely multiple outputs at different stages of the project)

• Peer-review publications – May 2028

• Summary of data for development of clinical guidelines – September 2028

• Publication of findings on University website – May 2028

• Patient workshops – to be conducted throughout the duration of the study with periodic updates on project findings, including June 2026, January 2027, September 2027, June 2028

The findings of this research study are expected to contribute to evidence-based decision-making for policy-makers, local decision-makers such as doctors, and patients to inform best practice to improve the care, treatment and experience of health care users relevant to the subject matter of the study.

The use of the data could:

• help the system to better understand the health and care needs to achieve meticulous selection of patients for intensive care to improve clinical outcomes as well as potentially reducing delays and cancellations to surgery.

• lead to the identification of vascular surgical patients undergoing lower limb bypass and major amputations for intensive care.

• advance understanding of regional and national trends in health and social care needs, improve postoperative outcomes and optimise resource usage in a resource-scarce NHS recovering from the COVID-19 pandemic.

• inform decisions on how to effectively allocate and evaluate resources according to health needs. For example reduced ICU admissions and shorter hospital stays can lead to measurable cost reductions and reduce burden on intensive care capacity.

• provide a mechanism for checking the quality of care. This could include identifying areas of good practice to learn from, or areas of poorer practice which need to be addressed.

• support knowledge creation or exploratory research (and the innovations and developments that might result from that exploratory work). The methodology used in this study will inform future packages of work investigating intensive care use for other surgical procedures within and outside of vascular surgery. Novel statistical analyses using registry data can address the NICE Real World Evidence framework and inform further programme grants.

It is hoped that through publication of findings in appropriate media, the findings of this research will add to the body of evidence that is considered by the bodies, organisations and individual care practitioners charged with making policy decisions for or within the NHS or treatment decisions in relation to specific patients

The findings of the study will be disseminated to the public via national charities (e.g. the Circulation Foundation) and national bodies (e.g. Vascular Society of Great Britain and Ireland, Faculty of Intensive Care Medicine), in addition to the aforementioned patient workshops. A wider collaborative group including leaders and stakeholders in these groups, as well as PPI groups, will also advise on appropriate channels for dissemination.

Yielded Benefits is not a requirement for new applications.