Condition category
Circulatory System
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
The COVER study is an international study aiming to assess how the COVID-19 coronavirus pandemic has changed the medical care of patients who have artery and vein problems. It consists of three separate projects or "Tiers". The 1st Tier is an internet based survey where doctors and healthcare professionals are asked some questions (every week) about how the care of these patients has changed. The 2nd Tier is a study where each hospital inputs the nature of the surgeries performed every week on an online database. The 3rd Tier is similar to the 2nd Tier; it will collect information on what happens to patients having artery or vein surgery during the pandemic. Finally, we will collect information regarding what happened to these patients for a year.

This study will help healthcare professionals understand how the COVID-19 pandemic has changed the care of patients with artery and vein problems. This is an important question, as patients with such health problems typically have many other health issues and/or are elderly. This makes them it more likely for them to develop COVID-19 related problems and life threatening complications.

Who can participate?
Any patient with a vascular condition.

What does the study involve?
Health professionals at participating centres will complete an online survey regarding vascular surgery that has been carried out.

What are the possible benefits and risks of participating?

Where is the study run from?
University Hospital Coventry and Warwickshire (UK)

When is the study starting and how long is it expected to run for?
April 2020 to April 2022

Who is funding the study?
National Institute for Health Research (NIHR) (UK)

Who is the main contact?
1. Ruth Benson (public),
2. Prof Christopher Imray (scientific),
3. Athanasios Saratzis (scientific),
4. Sandip Nandhra (public),

Trial website

Contact information



Primary contact

Miss Ruth Benson


Contact details

Vascular and Endovascular Research Network (President)
B15 2QU
United Kingdom
+44 (0)121 4143344



Additional contact

Prof Christopher Imray


Contact details

University Hospitals Warwickshire
Department of Vascular Surgery
United Kingdom
+44 (0)247 6964000



Additional contact

Mr Athanasios Saratzis


Contact details

BHF Cardiovascular Research Facility
Glenfield Hospital
United Kingdom
+44 (0)121 2524178



Additional contact

Mr Sandip Nandhra


Contact details

Vascular and Endovascular Research Network
United Kingdom
+44 (0)191 2336161

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number

COVER_01, IRAS 282224

Study information

Scientific title

The impact of the COVID-19 pandemic on the provision, practice, and outcomes of vascular surgery. An international cohort study (COVER)



Study hypothesis

The COVID-19 pandemic has already had a significant impact on worldwide healthcare systems. There is an urgent need to quantify the specific impact on the provision of vascular and endovascular surgery and the adjustments made to standard vascular practice in light of the pandemic.

Ethics approval

Approved 02/04/2020, Liverpool Central NHS Research Ethics Committee (Barlow House, 3rd Floor, 4 Minshull Street, Manchester, M1 3DZ, UK; +44 (0)207 104 8056;, ref: 20/NW/0196

Study design

Observational longitudinal study

Primary study design


Secondary study design

Longitudinal study

Trial setting


Trial type


Patient information sheet

Available for download (alongside all documents) at the study website.


Any vascular condition, including: aortic or other type of aneurysmal disease, peripheral arterial disease, venous disease, vascular malformations, trauma, major haemorrhage, access (for renal dialysis), carotid (and cerebrovascular) disease, any other type of pathology treated by vascular surgeons.


This project is a three-tiered study designed to fully elucidate the impact of the COVID-19 pandemic on vascular surgery across the world.

The aim of Tier 1 is to document how the provision and availability of vascular services evolves over time per unit/region/country.

The aim of Tier 2 is to prospectively capture data on all vascular procedures performed during the pandemic and understand the impact on outcomes in the short and medium-term (up to 1 year).

The aim of Tier 3 is to document (prospectively) deviations from standards of care/practice during the pandemic in vascular patients.

The main objective of the COVER study is to understand and evaluate the impact of the COVID-19 pandemic on global vascular practice and the effect on outcomes for patients presenting/receiving treatment during the pandemic.
Population (patients) – All patients with a vascular pathology.
Outcome of interest – Tier 1: state of vascular services per centre weekly; Tier 2: procedures performed in each centre; Tier 3: assessment of longer-term outcomes.
Time – end of study 12 months after the end of the COVID19 pandemic.

The study is formally supported by the Vascular Society of Great Britain and Ireland (VSGBI), the British Society for Endovascular Therapy (BSET), the Rouleaux Club, the NIHR, SingVasc and several national vascular surgery societies in Europe, Asia, Australia, New Zealand, and the Americas.

Intervention type



Drug names

Primary outcome measure

1. Structure and processes within the vascular service measured using a novel online questionnaire weekly until the end of data collection
2. Document all vascular surgery and interventional procedures performed using an online purpose-built data collection tool (per centre/patient) at baseline, time/date of surgery, date of discharge from hospital, three, six, and twelve months:
2.1. Type of procedure performed
2.2. Time taken from presentation to the surgical team to intervention
2.3. Mode of referral (primary vs. secondary care)
2.4. Site of surgery – hub or spoke hospital
2.5. Imaging modalities used and timings
2.6. Emergency classification i.e. urgent/emergency/elective
2.7. Operative technique(s) and device(s) used
2.8. Mode(s) of anaesthesia (local, regional, general, locoregional, other)
2.9. Whether suspected or confirmed COVID-19 positive (+ve) at time of surgery, COVID-19 +ve after surgery, or COVID-19 negative (-ve)
2.10. Documentation of changes to usual practice for this specific procedure as per surgeon’s standard protocol (type of procedure, type of anaesthetic, post-procedural destination)
3. Management of all referred urgent vascular cases using the online survey, focusing on:
3.1. Chronic Limb Threatening Ischaemia (CLTI):
3.1.1. Decision to discharge/admit/refer to a "hot"/emergency clinic
3.1.2. Decision for endovascular or open surgery first
3.1.3. Decision for best medical therapy or palliation or primary amputation
3.2. Carotid disease:
3.2.1. Number of patients managed with best medical therapy (BMT)
3.2.2. Modifications to the indication and decision for carotid endarterectomy (CEA)
3.2.3. Delays to treatment due to lack of theatre/bed availability
3.3. Abdominal Aortic Aneurysm (AAA)
3.3.1. Increasing use of Endovascular repair (if applicable)
3.3.2. Changes to criteria for intervention
3.3.3. Decisions for palliation, i.e. ‘turn down’
3.4. Acute Aortic syndrome (AAS)
3.4.1. Decision to manage in non-critical care beds
3.4.2. Changes to imaging protocol at unit level
3.4.3. Decision to defer surgery

Secondary outcome measures

1. Collected after surgery has been performed at three, six, and twelve months using patient records:
1.1. Re-admission
1.2. Re-intervention
1.3. All-cause mortality
1.4. Operation-specific morbidity
1.5. Morbidity
1.6. [If COVID-19 +ve] - respiratory outcome, admission to intensive care unit
2. Condition-specific outcomes at 3, 6 months and 1 year:
2.1. CLTI - limb salvage, amputation free survival, all-cause mortality
2.2. Carotid disease - ipsilateral stroke rate, any stroke rate, all-cause mortality
2.3. AAA - aneurysm-related mortality, all-cause mortality
2.4. AAS - complication rate including ruptures, all-cause mortality

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

Any patient with a vascular condition

Participant type


Age group




Target number of participants

20 centres, 10 patients from each centre

Participant exclusion criteria

Does not meet inclusion criteria

Recruitment start date


Recruitment end date



Countries of recruitment

Afghanistan, Albania, Algeria, American Samoa, Andorra, Angola, Anguilla, Antarctica, Antigua and Barbuda, Argentina, Armenia, Aruba, Australia, Austria, Azerbaijan, Bahamas, Bahrain, Bangladesh, Barbados, Belarus, Belgium, Belize, Benin, Bermuda, Bhutan, Bolivia, Bonaire Saint Eustatius and Saba, Bosnia and Herzegovina, Botswana, Bouvet Island, Brazil, British Indian Ocean Territory, Brunei, Bulgaria, Burkina Faso, Burundi, Cambodia, Cameroon, Canada, Cape Verde, Cayman Islands, Central African Republic, Chad, Chile, China, Christmas Island, Cocos (Keeling) Islands, Colombia, Comoros, Congo, Congo, Democratic Republic, Cook Islands, Costa Rica, Cote d'Ivoire, Croatia, Cuba, Curacao, Cyprus, Czech Republic, Denmark, Djibouti, Dominica, Dominican Republic, Ecuador, Egypt, El Salvador, Equatorial Guinea, Eritrea, Estonia, Ethiopia, Falkland Islands, Faroe Islands, Fiji, Finland, France, French Guiana, French Polynesia, French Southern Territories, Gabon, Gambia, Georgia, Germany, Ghana, Gibraltar, Greece, Greenland, Grenada, Guadeloupe, Guam, Guatemala, Guernsey, Guinea, Guinea-Bissau, Guyana, Haiti, Heard Island and Mcdonald Islands, Holy See (Vatican City State), Honduras, Hong Kong, Hungary, Iceland, India, Indonesia, Iran, Iraq, Ireland, Isle of Man, Israel, Italy, Jamaica, Japan, Jersey, Jordan, Kazakhstan, Kenya, Kiribati, Korea, North, Korea, South, Kosovo, Kuwait, Kyrgyzstan, Laos, Latvia, Lebanon, Lesotho, Liberia, Libya, Liechtenstein, Lithuania, Luxembourg, Macao, Macedonia, Madagascar, Malawi, Malaysia, Maldives, Mali, Malta, Marshall Islands, Martinique, Mauritania, Mauritius, Mayotte, Mexico, Micronesia, Federated States of, Moldova, Monaco, Mongolia, Montenegro, Montserrat, Morocco, Mozambique, Myanmar, Namibia, Nauru, Nepal, Netherlands, Netherlands Antilles, New Caledonia, New Zealand, Nicaragua, Niger, Nigeria, Niue, Norfolk Island, Northern Mariana Islands, Norway, Oman, Pakistan, Palau, Palestinian Territory, Panama, Papua New Guinea, Paraguay, Peru, Philippines, Pitcairn, Poland, Portugal, Puerto Rico, Qatar, Reunion, Romania, Russian Federation, Rwanda, Saint Barthelemy, Saint Helena, Saint Kitts and Nevis, Saint Lucia, Saint Martin (French part), Saint Pierre and Miquelon, Saint Vincent and the Grenadines, Samoa, San Marino, Sao Tome and Principe, Saudi Arabia, Senegal, Serbia, Seychelles, Sierra Leone, Singapore, Sint Maarten (Dutch part), Slovakia, Slovenia, Solomon Islands, Somalia, South Africa, South Georgia and the South Sandwich Is, South Sudan, Spain, Sri Lanka, Sudan, Suriname, Svalbard and Jan Mayen, Swaziland, Sweden, Switzerland, Syria, Taiwan, Tajikistan, Tanzania, Thailand, Timor-Leste, Togo, Tokelau, Tonga, Trinidad and Tobago, Tunisia, Turkey, Turkmenistan, Turks and Caicos Islands, Tuvalu, Uganda, Ukraine, United Arab Emirates, United Kingdom, United States Minor Outlying Islands, United States of America, Uruguay, Uzbekistan, Vanuatu, Venezuela, Viet Nam, Virgin Islands, British, Virgin Islands, U.S., Wallis and Futuna, Western Sahara, Yemen, Zambia, Zimbabwe

Trial participating centre

University Hospital Coventry and Warwickshire (lead Research and Development centre)
University Hospital Coventry and Warwickshire, RD&I (FAO Professor Imray)
United Kingdom

Sponsor information


University Hospitals Coventry and Warwickshire NHS Trust

Sponsor details

University Hospitals Warwickshire
Department of Research and Development (FAO Professor Imray)
United Kingdom
+44 (0)2476964000

Sponsor type

Hospital/treatment centre



Funder type


Funder name

National Institute for Health Research

Alternative name(s)


Funding Body Type

government organisation

Funding Body Subtype

National government


United Kingdom

Results and Publications

Publication and dissemination plan

Planned publication in a high-impact peer-reviewed journal.

This is an international effort led by the Vascular and Endovascular Research Network (VERN). The COVER study follows a collaborative authorship policy. All collaborators, including nurses, students, trainees, doctors, and other healthcare professionals, can be eligible for authorship. You can access the authorship policy here:

Intention to publish date


Participant level data

Available on request

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

14/04/2020: Trial’s existence confirmed by NHS Health Research Authority