COVID-19: Lessons learned in vascular surgery

Christian-Alexander Behrendt MD¹, Arun D. Pherwani MD², Max V. Wohlauer MD³

¹ Research Group GermanVasc, Department of Vascular Medicine, University Heart and Vascular Center UKE Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

² Staffordshire & South Cheshire Vascular Network, Royal Stoke University Hospital, Stoke-On-Trent, UK

³ Division of Vascular Surgery, Department of Surgery, University of Colorado School of Medicine, Aurora, Colo

Corresponding author:

Assoc. Prof. Dr. Christian-Alexander Behrendt, MD, FESVS, Head of Research Group GermanVasc, Dept of Vascular Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. E-mail: behrendt@hamburg.de 

On 31^st December 2019, a novel SARS coronavirus (SARS-CoV-2) was first described in Wuhan, Hubei Province, China.¹Wang C, Horby PW, Hayden FG, Gao GF. A novel coronavirus outbreak of global health concern. Lancet 2020;395:470-73.  In less than one month, it spread rapidly, causing an outbreak of acute and severe respiratory illness, first announced by the World Health Organization (WHO) on 5^th January 2020 (https://www.who.int/emergencies/disease-outbreak-news/item/2020-DON229). Several countries ultimately implemented strict infection control measures starting in March 2020. Amongst others, elective in-hospital procedures were widely cancelled or postponed providing additional capacity for the treatment of patients with COVID-19 infection. Since that time, the world has faced multiple waves of COVID-19 infection, and at the time of the writing this chapter, infection rates from the Omicron variant have reached worrying levels in many countries.

From a global perspective, the various healthcare systems reacted and adapted their acute care differently, partly due to wide variations in terms of available hospital beds, intensive care capacity, and healthcare expenditure. Less than 6% of the annual gross domestic product is spent on health care in countries such as Indonesia, Turkey, India, China, Luxembourg, and Russia, while France, Germany, the UK, and the US spent more than 12%. In other words, less than 2000 US dollars per capita is spent in some countries compared to more than 5000 dollars in others.²OECD. Doctors consultations. https://www.oecd-ilibrary.org/content/data/173dcf26-en – Accessed: 07 May 2020. These differences are also emphasised by the varying number of hospitals, general and intensive care hospital beds. Germany currently has more than 1600 general hospitals (650 vascular units) providing health benefits for 83 million people, which results in 7.9 beds per 1000 inhabitants. The situation in Italy (60 million people,  1059 hospitals, 200 vascular units and 3.2 beds) or Sweden (10 million people, 75 hospitals,  28 vascular units and 2.1 beds) is certainly different. Besides, it is commonly known that administrative measures, transfer practice, virus variants (alpha, beta, gamma, delta, omicron), and vaccination rates differ widely between countries.

Two years after the first outbreak, COVID-19 has been the subject of more than 200,000 publications registered on PubMed and more than 3215 trial protocols submitted to ClinicalTrials.gov. Despite an unprecedented interest from the medical community as well as the public, a considerable proportion of pandemic-related information still relies on results from small observational studies.

An important and generally unsolved question is whether infection with SARS-CoV-2 or, in addition the restriction measures as a result have led to adverse outcomes in patients with acute vascular conditions. It has become evident that a COVID-19 infection related coagulopathy may have caused excess thromboembolic events. This chapter aims to illuminate the potential overlaps and impact of the ongoing COVID-19 pandemic on vascular surgery.

There are many ways in which the ongoing pandemic may have (directly or indirectly) affected clinical practice in vascular surgery. A considerable number of patients may require an intensive care unit (ICU) stay after vascular surgery. Typical procedures affected include carotid artery surgery, complex endovascular or open aortic repair, and complex peripheral bypass surgery. While the duration of the operation, amount of blood loss, and occurrence of complications may predict the need for ICU care following surgery, clinical practice often differs between countries and even between hospitals. It is evident that the lack of  ICU beds is a bottleneck, especially in high-volume academic centres where patients with COVID-19  and other severe illnesses are often treated. This emphasises the importance of population-based data that can address cancellation rates between the different health care providers. Many colleagues reported that staff from vascular surgery departments were temporarily seconded to external units directly involved in the treatment of patients with COVID-19 (e.g., intensive care).

Due to staff shortage and additional protective measures against the coronavirus (e.g., antigen or polymerase chain reaction testing of staff and patients), many processes in the health care system were substantially delayed. It seems likely that patients with urgent vascular conditions faced delays from first presentation to the outpatient or hospital care for definitive treatment. It was also possible that patients were less likely to present to health services, especially during lockdown and acute pandemic waves.¹Aziz F, Behrendt C-A, Sullivan K, Beck AW, Beiles CB, Boyle JR, et al. The impact of COVID-19 pandemic on vascular registries and clinical trials. Seminars in vascular surgery 2021;34:28-36.

Many countries have adapted their patient-selection and priorities for vascular surgical procedures. Most centres continued treating ruptured aortic aneurysm (rAAA) or dissection, acute limb ischaemia (ALI), critical mesenteric ischaemia, chronic limb-threatening ischaemia (CLTI), symptomatic carotid artery stenosis, and complicated or symptomatic aortic disease, with a graduated approach (Table 1).²Aziz F, Behrendt C-A, Sullivan K, Beck AW, Beiles CB, Boyle JR, et al. The impact of COVID-19 pandemic on vascular registries and clinical trials. Seminars in vascular surgery 2021;34:28-36. ,³Forbes TL. Vascular surgery activity condition is a common language for uncommon times. Journal of vascular surgery 2020;72:391-92.

Only few observational studies have been published concerning the impact of the pandemic on the treatment of peripheral arterial disease (PAD). In a cross-sectional study of 20 centres in the severely affected Campania region in Italy, a reduced rate of CLTI-related hospitalisations and an increased in-hospital amputation rate was reported during the lockdown.⁴Stabile E, Piccolo R, Franzese M, Accarino G, Bracale UM, Cappello E, et al. A cross-sectional study evaluating hospitalization rates for chronic limb-threatening ischemia during the COVID-19 outbreak in Campania, Italy. Vascular Medicine 2021;26:174-79.  However, as the authors frankly discussed, only patients who were admitted to the hospital were included in the analysis, while a non-registration bias due to transfer effects could not be addressed. Another retrospective cohort study included patients who were treated at a single Northern Italian centre. The authors determined the changes related to the Italian lockdown and found elective vascular surgery was scaled down by 50% starting from 09.03.2020.  While the number of emergency procedures did not reduce, emergency room access for non-urgent cases decreased.⁵Piazza M, Xodo A, Squizzato F, Conti G, Boemo D, Carretta G, et al. The challenge of maintaining necessary vascular and endovascular services at a referral center in Northern Italy during the COVID-19 outbreak. Vascular 2021;29:477-85.

In a retrospective cohort study including patients treated at a single centre in Lisbon, Portugal, a decline in outpatient clinics and inpatient admissions was observed. Confirming the Italian experience, the authors reported that most activity was maintained, particularly for patients with CLTI, although some staff had to be reallocated.⁶Duarte A, Gouveia EMR, Lopes A, Rato JP, Valente J, Pedro LM. Lessons Learned from the Impact of the COVID-19 Pandemic in a Vascular Surgery Department and Preparation for Future Outbreaks. Ann Vasc Surg 2021;73:97-106.

Musajee et al. reported how the COVID-19 pandemic impacted on the treatment and outcomes of patients with CLTI and diabetic foot infection in a single centre. Among 139 matched patients, they observed a significantly longer wait from the onset of symptoms to clinical presentation. Furthermore, the time from presentation to first intervention was significantly longer, and treatment during the pandemic was a predictor of worse primary patency and freedom from major adverse limb events.⁷Musajee M, Zayed H, Thulasidasan N, Sayed M, Francia F, Green M, et al. Impact of COVID-19 Pandemic on the outcomes in patients with Critical Limb Threatening Ischaemia and Diabetic Foot Infection. Ann Surg 2020.

Interestingly, while the few available observational studies demonstrate inconsistent impact of the pandemic on everyday clinical practice, survey studies suggest a more severe impact on vascular surgery. In a questionnaire of 535 vascular surgeons in the United States, the majority of participants reported substantial impact on their practice during the COVID-19 pandemic, while substantial regional variations were demonstrated.⁸Mouawad NJ, Woo K, Malgor RD, Wohlauer MV, Johnson AP, Cuff RF, et al. The impact of the COVID-19 pandemic on vascular surgery practice in the United States. Journal of Vascular Surgery 2021;73:772-79.e4.

In the UK, the first case of COVID-19 was reported on 29 January 2020 and the country went into lockdown on 23 March 2020. Two more waves and further lockdowns came into force from November 2020 to February 2021. By February 2022, UK authorities had recorded more than 17 million cases of COVID-19 infection and 180,000 people died within 28 days of infection, the highest rates in Europe. ¹Coronavirus (COVID-19) in the UK. https://coronavirus.data.gov.uk/ Accessed 10/02/2022. The UK COVID-19 vaccination programme started in December 2020 and more than 84% of the population aged 12 and over have received at least one dose of the vaccine at the time of writing.

In response to the pandemic, in a joint statement, the Vascular Society of Great Britain and Ireland (VSGBI) along with the British Society of Interventional Radiology (BSIR) and the Clinical Reference Group (CRG) for Vascular Services issued guidance recommending the postponement of elective aortic, peripheral arterial and venous procedures as well as procedures for asymptomatic carotid disease, in order to limit the use of critical care resources and reduce exposure of patients to hospitals with high risk of infection.²he Vascular Society for Great Britain and Ireland. COVID-19 Virus and Vascular Surgery. 2020;https://www.vascularsociety.org.uk/professionals/news/113/covid19_virus_and_vascular_surgery. Accessed 11/01/2022 The National Vascular Registry (NVR) 2021 annual report revealed a significant reduction in elective vascular procedure volumes, which has been more marked in April 2020 and January 2021 (Figure 1.1 and 1.2).³

 

Waton S, Johal A, Birmpili P, Li Q, Cromwell D, O’Neill R, Williams R, Pherwani A. National Vascular Registry: 2021 Annual Report. London: The Royal College of Surgeons of England, November 2021.
Elective activity recovered between the two waves, but did not reach pre-pandemic levels for elective lower limb procedures. Compared with April 2020, the second wave had less impact on non-elective procedures, whose volumes remained stable in 2021. Notably, there was an increase in the proportion of patients undergoing endovascular AAA repair in the peak COVID periods, compared to the pre-pandemic period (64% vs 59% pre-pandemic for elective infra-renal AAA repair, 84% vs 72% prepandemic for other elective (e.g., complex) AAA repair). ⁴Cromwell D, Birmpili P, Johal A, Li Q, Waton S, O’Neill R, Williams R, Boyle J, Pherwani A. Impact of COVID-19 disease on the provision of vascular surgery in the UK National Health Service in 2020. May 2021 Update. London: The Royal College of Surgeons of England, 2021

To capture the impact of the pandemic on patient outcomes, the NVR introduced new data items pertaining to COVID-19, such as whether the patient had symptoms, pre-operative or postoperative COVID diagnosis, and if the timing and the type of the vascular procedure had changed.⁵Vascular Services Quality Improvement Programme. NVR COVID-19 dataset. https://www.vsqip.org.uk/resources/proformas/nvr-covid-19-dataset/ Accessed 10/02/2022 Based on data from patients undergoing vascular procedures in the UK from March to October 2020, the preoperative infection rate was less than 0.5%, apart from lower limb amputations, where the rate was 1.8%, while the postoperative infection rate was higher overall (1.4%). ⁶Cromwell D, Birmpili P, Johal A, Li Q, Waton S, O’Neill R, Williams R, Boyle J, Pherwani A. Impact of COVID-19 disease on the provision of vascular surgery in the UK National Health Service in 2020. May 2021 Update. London: The Royal College of Surgeons of England, 2021 The pandemic also had limited impact on the timing of non-elective procedures. However, 25% of patients awaiting elective AAA repair and 19% awaiting lower limb bypass had their procedure delayed or cancelled. The effect on those undergoing non-elective endovascular treatment for peripheral arterial disease was less pronounced, with 11% experiencing a change in the timing of their procedure.

Regarding postoperative outcomes, the risk of in-hospital death was higher among patients with coronavirus compared to those without an infection, particularly for patients with a respiratory complication. Indicatively, the in-hospital mortality rate among patients undergoing AAA repair or revascularisation from March to October 2020 without respiratory complications was 2.5% if they had not contracted coronavirus and 6.7% if they had. Among patients that experienced a respiratory complication, the mortality rate was 27.8% for COVID-negative and 42.6% for COVID-positive patients. However, the estimated excess mortality within the whole population of vascular patients was modest overall due to the limited number of COVID-19 infections. During the first wave (March – June 2020), the overall standardised mortality ratio (observed/expected mortality) was estimated to be 1.02 (95% CI 0.87 to 1.19), comparable to the recovery period (July-October 2020), when it was estimated to be 1.16 (95% CI 1.00 to 1.34).

It is still early to establish the impact of the pandemic on vascular surgery services in the UK, as the backlog of elective patients requiring treatment that were postponed during the pandemic is considerable and difficult to estimate.

The Centers for Disease Control confirmed the first case of COVID-19 in United States on January 20, 2020. During a 3-week interval towards the end of February into the beginning of March, the number of U.S. COVID-19 cases increased more than a thousand-fold, which led to a rapid and widespread cancellation of scheduled vascular surgical operations on an unprecedented scale. The American College of Surgeons, Society for Vascular Surgery, and international societies published guidelines triaging operations, and nearly all hospitals affected by the pandemic temporarily halted the performance of elective surgery during the exponential growth phase of the pandemic, and for a large portion of them, only emergency surgery was performed. ¹Bulletin: ACS COVID-19 Newsletter. Issue 2: March 24, 2020. https://www.facs.org/covid-19. Accessed June 1, 2020. On March 13, 2020, the American College of Surgeons (ACS) released COVID-19: Recommendations for Management of Elective Surgical Procedures, and recommended minimizing, postponing or cancelling electively scheduled surgery and invasive procedures. The ACS stated: Each hospital, health system, and surgeon should thoughtfully review all scheduled elective procedures with a plan to minimize, postpone, or cancel electively scheduled operations, endoscopies, or other invasive procedures until we have passed the predicted inflection point in the exposure graph and can be confident that our health care infrastructure can support a potentially rapid and overwhelming uptick in critical patient care needs.  ²COVID-19 Guidelines for Triage of Emergency General Surgery Patients: Published March 13, 2020. https://www.facs.org/covid-19/clinical-guidance/elective-surgery. Accessed March 13, 2020. On March 24, 2020, the Society for Vascular Surgery issued guidelines regarding elective vascular procedures and timelines for postponement. ³Vascular Surgery Triage Guidelines: Published March 24, 2020. https://vascular.org/news-advocacy/covid-19-resources#Guidelines&Tools. Accessed March 24, 2020. The Vascular Surgery COVID-19 Collaborative (VASCC), founded in March 2020 by Max Wohlauer, MD, at the University of Colorado and Robert Cuff, MD, at Michigan State University is an international multi-center observational study evaluating the impact of scheduled surgery postponement during the COVID-19 pandemic.

Jorge Miranda MD, et. al evaluated the impact of COVID-19 related delays in scheduled operations in patients with CLTI. The following interim data were collected for 165 patients in the United States: demographics, co-morbidities, wound ischaemia foot infection (WIfI) stage, indication and planned surgery, location of surgery, time delay, change in surgical plan and adverse events. Descriptive statistics were used for interim data. Among 165 index patients, the average delay to surgery was 59.3 days (± 50.4), [median of 47.0 days (1, 241)]. Among these, 66 patients had baseline WIfI grades and stages; wound grade 1 and 3 were equally prevalent 22 (33.3%), while ischaemia grade 3 was most prevalent (n=56, 84.8%). Foot infection grade 0 was the most prevalent 53 (80.3%). WIfI clinical stage 3- moderate risk for amputation was the most prevalent. The frequencies of surgical indications were: severe claudication 36 (21.8%), minor tissue loss 33 (20.0%), rest pain 27 (16.4%), and major tissue loss 26 (15.8%). Intervention for a threatened bypass occurred in 6 (3.6%) patients and for critical in-stent stenosis in 3 (1.8%). In the severe claudication group, 4 (11.1%) patients developed rest pain and 1 (2.7%) minor tissue loss during delay before planned intervention. In the minor tissue loss group, 1 (3.0%) patient progressed to extensive tissue loss. From the interim cohort, 8 (4.8%) delayed patients required conversion of planned, elective surgery to an urgent one. Indications for emergency surgery were: progressive tissue loss 5 (62.5%), critical in-stent restenosis 2 (25%), and threatened bypass 1 (12.5%). The primary major adverse event after emergency surgery was major limb amputation in 4/8 patients (50%). At this time, 10 (10/165 6.1%) limbs have required major limb amputation and 7 (4.2%) have required a minor amputation. The authors concluded that COVID-related delays in intervention for patients with severe PAD or CLTI led to a low  but unpredictable rate of decompensation. For the patients that required conversion of planned, elective procedure to an emergency operation, the outcomes were catastrophic, with a 50% rate of major amputation ⁴Miranda J, Wohlauer MV, Chung J, Al-Jundi W, Gillette R, Colborn K, Cuff R, Mills JL, On behalf of the Vascular Surgery COVID-19 Collaborative. Impact of COVID-19-Related Delays of Scheduled Operations in Patients with Chronic Limb Threatening Ischemia: Interim Data Analysis. Presented at Vascular Annual Meeting. San Diego, CA. August 18, 2021.

Kalpa Perera MD, et. al evaluated the impact of surgical delay and subsequent natural history of patients awaiting scheduled aortic operations. The VASCC registry identified 127 patients with aortic disease whose operations were postponed during the 2020 COVID-19 pandemic. This interim analysis was conducted approximately 10 months after commencement of the registry, based on data from centres in the United States. Data were collected on 127 planned aortic procedures with a mean age of 70.7 (SD 11.3) and 68.5% were men. The range of procedures delayed consisted of 100 (78.7%) fAAA repairs, 7 (5.5%) for acute aortic syndromes (penetrating aortic ulcer, intramural haematoma and subacute or chronic Type B dissection), and 18 (14.2%) endoleak procedures. At the time of the analysis, 89 (70%) of patients had completed interventions with a mean delay of 82.7 days, with one patient undergoing unsuccessful emergency repair for rAAA. Eighteen (14.2%) were still waiting for surgery at the time of completion of the case report form, consisting of 17 AAAs and one endoleak. Thirteen patients (10.2%) had their procedure permanently cancelled. Including the aforementioned rupture, another 5 patients (3.9%) were reported to have died after postponement of their aneurysm surgery. Mortality amongst aneurysm patients alone was 6% during the 10-month interval. The authors conclude that at the time of analysis, 70% of postponed aortic procedures were completed, with a mean delay of 82.7 days. Nevertheless, six patients died as a result of postponed surgery, including one aneurysm rupture. Overall mortality was 6 patients (4.7%) over 10 months from COVID-19 related health service disruption, which  underscores the wider impacts of this pandemic, and the importance of resource and contingency planning for future epidemics and natural disasters.⁵Perera K, Wohlauer MV, D’Oria M, Savlania A, Bath J, Colborn K, Cuff R, Chuen J, On behalf of the Vascular Surgery COVID-19 Collaborative.  Impact of COVID-19 on Patients Scheduled for Aortic Surgery: Interim Data Analysis. Presented at Vascular Annual Meeting. San Diego, CA. August 18, 2021.

Mahmood Kabeil MD, et. al evaluated 50 patients with carotid stenosis whose interventions were postponed during the COVID-19 pandemic surge in the United States in the VASCC interim data analysis. The mean age of the patients was 72.2 years (+/- SD 9.08), 47 % were men and 24 % were women; 74.0% of patients were White non-Hispanic, 18% were Hispanic, 2.0% were Asian or Pacific Islander, and 2% were Black non-Hispanic. Of the 50 patients, 72 % were asymptomatic, 10 % had previous stroke, 10 % had transient ischaemic attack (TIA), 4 % had amaurosis fugax. The average  surgical delay was 72.9 days (+/- SD 33.1), with a median of 71 days (IQR=42). Of the 50 patients, 28 (56%) had intervention completed successfully at time of data entry. No patient  required emergency surgery during the delay. Two patients (4.0%) with carotid disease died while waiting for surgery. The cause of death in both was unrelated to cerebrovascular disease. The authors reported that none of the asymptomatic patients became symptomatic during the delay This interim analysis supports institutional and national guidelines in the United States that intervention  for asymptomatic carotid stenosis may safely be postponed during a COVID-19 pandemic surge. Further data are needed to confirm the impact on patients with symptomatic carotid stenosis.⁶Mahmood Kabeil MD, Max Wohlauer MD, Faisal Aziz MD, Vipul Khetarpaul MD, Issam Koleilat MD, Riley Gillette BS, Kathryn Colborn PhD, Robert F. Cuff MD, and Nicolas J. Mouawad MD,  On behalf of the Vascular Surgery COVID-19 Collaborative. Impact Of Covid-19 On Patients Undergoing Scheduled Carotid Interventionsa: Interim Data Analysis. ESVS 35th Hybrid Annual Meeting September 28-29, 2021.

James Dorosh DO, et. al analyzed 170 patients with venous disease whose interventions were postponed during the COVID-19 pandemic surge in the United States as part of the VASCC interim data analysis. Among the 170 patients, the mean age was 54.6 years (range 15-89 years old) and 114 (67.1%) were women. Race included 55.9% White, 20.6% Hispanic, 11.8% Black, 2.4% Asian, and 9.4% were unknown. Venous diagnoses were 75.3% varicose veins with or without complications, 9.4% venous ulceration, 3.5% venous thoracic outlet syndrome, 3.5% lipodermatosclerosis, 1.8% acute deep vein thrombosis, 0.6% non-thrombotic iliac vein compression, and 5.9% other. Of these, 114 (67.1%) had procedures postponed, but completed successfully at the time of data entry. The average delay was 86.8 days, with a median of 70 days. Some 55 (32.4%) were still waiting for surgery at the time of completion of the case report form. No patient required an emergency procedure for their venous disease. The authors results support the American College of Surgeon’s Recommendation for Management of elective vascular surgical procedures. Interventions may safely be delayed for patients with venous disease requiring elective surgical intervention during the COVID-19 pandemic. They concluded that postponement of venous interventions would allow better allocation of limited resources during the pandemic.⁷ James Dorosh DO, Max Wohlauer MD, Mahmood Kabeil MD, Rafael Malgor MD, Leigh Ann O’Banion MD, Gabriel López Peña MD, Riley Gillette, Kathryn Colborn PhD, Robert Cuff MD, Judith Lin MD, MBA, On behalf of the Vascular Surgery COVID-19 Collaborative. Impact of COVID-19 on patients undergoing scheduled operations for venous disease: Interim Data Analysis. Presented at Vascular Annual Meeting. San Diego, CA. August 18, 2021.

Gabriel López Peña MD ChM, et. al performed an analysis of 177 patients with end stage renal disease (ESRD) undergoing dialysis intervention in the United States whose interventions were postponed during the COVID-19 pandemic surge. The average delay was 71.7 (SD 50.9). Of the patients, 132 (74.6%) had completed their surgery at time of data entry, while 44 (24.9%) were still waiting. One patient (0.6%) required emergency surgery during the delay. One patient (0.6%) died waiting for surgery and 5 (2.66%) died in the first 30 days following surgery.  The authors reported that COVID-19 has resulted in a major  shift in patient care around the world, and patients requiring vascular access are not an exception. The delay might change the patient’s potential for haemodialysisd access, as well affect their quality of life and expectancy. On  completion of this report, 44 (24.9%) patients were still waiting for their procedure. No doubt COVID-19 has changed global health policies and strategies, and adaptation will be required  to the  care of patients with ESRD.  ⁸ Lopez-Pena G, Wohlauer MV, Hinojosa C, Mier y Teran S, Cuff R, Chawla A, Gunawansa N, Sternbergh C, Gillette R, Colborn K, Guidry Lyons L, On behalf of the Vascular Surgery COVID-19 Collaborative. Impact of COVID-19 on patients undergoing scheduled hemodialysis operations: Interim Data Analysis. Presented at Vascular Annual Meeting. San Diego, CA. August 18, 2021.

The first official SARS-CoV-2 positive patient in Germany was registered on 27^th January 2020. As part of comprehensive restrictive measures, elective in-hospital procedures were widely cancelled or postponed in Germany, starting in March 2020. A nationwide lockdown came into force on 22 March 2020 and lasted 7 weeks to break the first pandemic wave. At the turn of 2020, a second wave hit Germany subsequently followed by a third wave in April/May 2021. Until  the turn of the year 2021,  the Delta variant was predominant, after which most federal states registered first infected patients with the Omicron variant. At that time, almost 6.2 million were infected and more than 100,000 died in Germany. As of December 2021, approximately 70% of the German population had received at least two vaccinations.

Few population-based studies using nationwide administrative registries from Germany are available addressing the impact of the pandemic on vascular care. In a health insurance claims study including 115,720 hospitalisations for acute cardiovascular and cerebrovascular emergencies (for myocardial infarction, acute stroke, TIA, ALI, and rAAA), admission rates declined markedly during the pandemic, while patients’ comorbidities and treatment allocations remained unchanged (mean age 72.9 years, 51.3% women). When compared with the pre-COVID interval, the monthly rate of admission of patients with ALI declined by 12%.¹Seiffert M, Brunner FJ, Remmel M, Thomalla G, Marschall U, L’Hoest H, et al. Temporal trends in the presentation of cardiovascular and cerebrovascular emergencies during the COVID-19 pandemic in Germany: an analysis of health insurance claims. Clin Res Cardiol 2020;109:1540-48.

In a follow-up study of 316,718 hospitalisations, the SARS-CoV-2 infection status, which was available since March 2020, was used to determine the association between infection and in-hospital mortality. In-hospital mortality increased during the COVID-19 pandemic when compared with the three previous years for patients with acute stroke from 8.3% to 9.6%. Amongst all patients, 2.4% had confirmed infection with SARS-CoV-2. A higher in-hospital mortality was observed for acute stroke (12.4% vs. 9.0%) and ALI (14.3% vs. 5.0%) if a concomitant infection was registered.²Behrendt CA, Seiffert M, Gerloff C, L’Hoest H, Acar L, Thomalla G. How Does SARS-CoV-2 Infection Affect Survival of Emergency Cardiovascular Patients? A Cohort Study From a German Insurance Claims Database. Eur J Vasc Endovasc Surg 2021.  A decline in admission rates was also confirmed in an international survey on acute and chronic aortic conditions. In that study, Germany was the only country where a significant decrease in acute cases was seen (decrease by 22%, p=0.006).³Czerny M, Gottardi R, Puiu P, Bernecker OY, Citro R, Della Corte A, et al. Impact of the coronavirus disease 2019 (COVID-19) pandemic on the care of patients with acute and chronic aortic conditions. Eur J Cardiothorac Surg 2021;59:1096-102.

As of December 2021, there have been 1.2 million confirmed cases of COVID-19, with more than 15,000 cumulative deaths. In April 2020, the Swedish National Registry for Vascular Surgery (Swedvasc) introduced variables in their registry which could be used for research on the impact of COVID-19 on vascular surgical care. The Swedish strategy for management of COVID-19 differed from many other countries, with no formal lockdowns during 2020. Interestingly, the overall number of arterial procedures including operations for acute and chronic limb ischaemia had not changed in 2020 when compared with the previous years (Figure 3), while a significant decrease of venous procedures and procedures provided to patients with intermittent claudication was observed. ¹Björses K, Blomgren L, Holsti M, Jonsson M, Smidfelt K, Mani K. Editor’s Choice – The Impact of Covid-19 on Vascular Procedures in Sweden 2020. European journal of vascular and endovascular surgery : the official journal of the European Society for Vascular Surgery 2021;62:136-37.

Evidence for acute arterial embolism and acute limb ischaemia

The results of numerous case reports as well as small case series including patients with COVID-19 and ALI that have been published in 2020 and 2021 led to an ongoing discussion concerning thromboembolic arterial events in infected patients.¹Kaur P, Qaqa F, Ramahi A, Shamoon Y, Singhal M, Shamoon F, et al. Acute upper limb ischemia in a patient with COVID-19. Hematol Oncol Stem Cell Ther 2021;14:348-50. ,²Perini P, Nabulsi B, Massoni CB, Azzarone M, Freyrie A. Acute limb ischaemia in two young, non-atherosclerotic patients with COVID-19. The Lancet 2020;395:1546. , ³Silingardi R, Gennai S, Migliari M, Covic T, Leone N. Acute limb ischemia in COVID-19 patients: Could aortic floating thrombus be the source of embolic complications? J Vasc Surg 2020;72:1152-53. , ⁴Topcu AC, Ozturk-Altunyurt G, Akman D, Batirel A, Demirhan R. Acute Limb Ischemia in Hospitalized COVID-19 Patients. Ann Vasc Surg 2021;74:88-94. , ⁵Gomez-Arbelaez D, Ibarra-Sanchez G, Garcia-Gutierrez A, Comanges-Yeboles A, Ansuategui-Vicente M, Gonzalez-Fajardo JA. COVID-19-Related Aortic Thrombosis: A Report of Four Cases. Ann Vasc Surg 2020;67:10-13. , ⁶Tayebi P, Zavareh MSH, Tayyebi G, Abdollahi FZ, Mahmoudlou F. Extensive Acute Lower Extremity Arterial Thrombosis: A Major Thrombus Formation Caused by COVID-19. Vasc Specialist Int 2021;37:36. ,⁷Chowdhry E, Moshman J, Carroll S. A Case of COVID-19 Related Coagulopathy Complications and Heparin Resistance. Cureus 2021;13:e18265. , ⁸Aasen M, Blecha M. Percutaneous Revascularization for COVID-19 Induced Spontaneous Arterial Thrombosis. Vascular and Endovascular Surgery 2021:15385744211010445. , ⁹Omar T, Papp L, Youseff A, Sargious A, Jararah H. A rare case of bilateral acute lower limb ischemia in a non-atherosclerotic patient with COVID-19 infection. Int Angiol 2021;40:84-86. ,¹⁰Maurera AH, Vu JH, Rehring TF, Layman PF, Johnson SP. Acute Limb Ischemia in Minimally Symptomatic SARS-CoV-2 Infection. J Vasc Interv Radiol 2020;31:2150-53. , ¹¹Gubitosa JC, Xu P, Ahmed A, Pergament K. COVID-19-Associated Acute Limb Ischemia in a Patient on Therapeutic Anticoagulation. Cureus 2020;12:e10655. , ¹²Galanis N, Stavraka C, Agathangelidis F, Petsatodis E, Giankoulof C, Givissis P. Coagulopathy in COVID-19 infection: a case of acute upper limb ischemia. J Surg Case Rep 2020;2020:rjaa204. ,¹³Ali Nasir S, Arif A, Shahid M, Ahmed Y, Riaz B, Sherwani NZF. Acute Limb Ischemia in a Patient With COVID-19 Pneumonia. Cureus 2021;13:e18574. , ¹⁴Kartikasari U, Djajalaksana S, Martini H. Acute limb ischemia in a patient with Covid-19 pneumonia: a case report. J Thromb Thrombolysis 2021;52:974-79. , ¹⁵Singh B, Aly R, Kaur P, Gupta S, Vasudev R, Virk HS, et al. COVID-19 Infection and Arterial Thrombosis: Report of Three Cases. Ann Vasc Surg 2021;70:314-17. ,¹⁶Topcu AC, Ariturk C, Yilmaz E. Acute limb ischemia in a COVID-19 patient. Thrombosis Update 2021;2:100031. .    In a retrospective single-centre observational study of 20 SARS-CoV-2 positive patients with ALI the authors concluded that the incidence significantly increased during the COVID-19 pandemic in the severely affected Italian Lombardy region. It was further believed that successful revascularisation was less often achieved than expected and that this was believed to be related to the virus.¹⁷Bellosta R, Luzzani L, Natalini G, Pegorer MA, Attisani L, Cossu LG, et al. Acute limb ischemia in patients with COVID-19 pneumonia. J Vasc Surg 2020;72:1864-72.  In another multicentre study by the same authors, COVID-19 infection was reported to be a marker of poor outcomes in terms of mortality and postoperative complications.¹⁸Bellosta R, Piffaretti G, Bonardelli S, Castelli P, Chiesa R, Frigerio D, et al. Regional Survey in Lombardy, Northern Italy, on Vascular Surgery Intervention Outcomes During The COVID-19 Pandemic. Eur J Vasc Endovasc Surg 2021;61:688-97.  The results of these two preliminary studies were later confirmed by a review including 36 studies and 194 patients, showing a considerably low success rate and high mortality.¹⁹Attisani L, Pucci A, Luoni G, Luzzani L, Pegorer MA, Settembrini AM, et al. COVID-19 and acute limb ischemia: a systematic review. J Cardiovasc Surg (Torino) 2021. Unfortunately, due to the retrospective observational design of these studies and lack of proper comparison groups, it is not possible to decide if the virus infection led either directly or indirectly to an arterial event, or if both entities were coincidently diagnosed (Table 2). Furthermore, it appears likely that a change of referral practice and centralisation may have affected the case-mix in certain centres and regions, while population-based data with high external validity remain sparse. This uncertainty is further emphasised by the fact that an association between cardiovascular disease including PAD and severe illness was previously reported. Hence, the proportion of patients with clinically relevant atherosclerosis amongst hospitalised COVID-19 cohorts is most likely higher, affecting associations between the disease, inpatient treatment, and thromboembolic events. Another underlying explanation may be the suspected collateral damage of patients in need of extracorporeal membrane oxygenation (ECMO), especially in patients with severe cardiovascular disease burden. In a retrospective series of 113 patients treated with ECMO for Influenza or COVID-19, approximately 4.4% developed severe leg ischaemia with no differences between either entity.²⁰Roedl K, Kahn A, Jarczak D, Fischer M, Boenisch O, de Heer G, et al. Clinical Characteristics, Complications and Outcomes of Patients with Severe Acute Respiratory Distress Syndrome Related to COVID-19 or Influenza Requiring Extracorporeal Membrane Oxygenation-A Retrospective Cohort Study. Journal of clinical medicine 2021;10:5440.   Unfortunately, most case reports, case series, and observational studies did not report if iatrogenic vascular damage due to intensive care management was a reason for ALI. In a Cochrane review on the association between COVID-19 and cardiovascular events, the authors concluded that cardiometabolic comorbidities are common in people who are hospitalised with a COVID-19 infection, and cardiovascular complications are frequent.²¹Pellicori P, Doolub G, Wong CM, Lee KS, Mangion K, Ahmad M, et al. COVID-19 and its cardiovascular effects: a systematic review of prevalence studies. Cochrane Database Syst Rev 2021;3:Cd013879.  Confirming these conclusions, other authors found that conditions connected with a poor state of health, as well as organ damage and coagulation dysfunction were associated with an increased risk of severe and fatal disease.²²Wolff D, Nee S, Hickey NS, Marschollek M. Risk factors for Covid-19 severity and fatality: a structured literature review. Infection 2021;49:15-28.

In a single centre analysis of 65 patients who were treated with ALI before, during, and after the US Massachusetts, COVID-19 state of emergency declaration, the authors concluded that during COVID-19, patients were less likely to seek medical attention. When patients suffering from ALI do present, however, their severity is worse, as shown by increased multilevel disease and more likely to require an amputation.²³Siu M, Lin A, Narvaez V, Perez A, Norris M, Kronick M, et al. Analysis of Outcomes in Acute Limb Ischemia Patients during COVID-19 State of Emergency in Western Massachusetts. Journal of Vascular Surgery 2021;73:38-39.  In a multicentre study of institutions in France and Italy, the authors identified 20 patients with 24 thromboembolic arterial events amongst 209 admitted patients. Only 3/24 (13%) affected the limb, and the authors concluded that severe arterial events might occur in COVID-19 patients, but the exact incidence remains to be investigated.²⁴de Roquetaillade C, Chousterman BG, Tomasoni D, Zeitouni M, Houdart E, Guedon A, et al. Unusual arterial thrombotic events in Covid-19 patients. Int J Cardiol 2021;323:281-84.  Another multicentre approach was recently published by the Clinical Research in Intensive Care and Sepsis Trial Group for Global Evaluation and Research in Sepsis (CRICS TRIGGERSEP) Group. Using data from four intensive care units in France comprising 150 patients with COVID-19, only one had limb ischaemia. Among 27 thromboembolic complications, the majority were pulmonary embolism.²⁵Helms J, Tacquard C, Severac F, Leonard-Lorant I, Ohana M, Delabranche X, et al. High risk of thrombosis in patients with severe SARS-CoV-2 infection: a multicenter prospective cohort study. Intensive care medicine 2020;46:1089-98.  In a larger single centre study comprising 1300 patients admitted consecutively with COVID-19 between November 2020 and December 2020, less than 1% had ALI and most of them developed symptoms after being admitted to the hospital.²⁶Al-Zoubi N, Shatnawi N, Jarbo H. Acute Lower Limb Ischemia in Patients Infected with COVID-19. International journal of general medicine 2021;14:833-39.

Besides data derived from clinical cohorts, in large consecutive postmortem studies, only a few (<1%) arterial thromboembolic events were observed, while venous thrombosis and pulmonary embolism were diagnosed in 39.2% and 22.1%, respectively.²⁷Fitzek A, Schädler J, Dietz E, Ron A, Gerling M, Kammal AL, et al. Prospective postmortem evaluation of 735 consecutive SARS-CoV-2-associated death cases. Scientific reports 2021;11:19342-42. ,²⁸Wichmann D, Sperhake JP, Lutgehetmann M, Steurer S, Edler C, Heinemann A, et al. Autopsy Findings and Venous Thromboembolism in Patients With COVID-19. Ann Intern Med 2020. , ²⁹Edler C, Schröder AS, Aepfelbacher M, Fitzek A, Heinemann A, Heinrich F, et al. Dying with SARS-CoV-2 infection—an autopsy study of the first consecutive 80 cases in Hamburg, Germany. International Journal of Legal Medicine 2020;134:1275-84. .

Evidence for deep vein thrombosis and pulmonary embolism

In contrast to the inconsistent evidence for arterial embolism, several systematic reviews clearly and consistently suggest an association between COVID-19 and venous thromboembolism including pulmonary embolism (PE) and deep vein thrombosis (DVT), although the included cohorts differed significantly. There, the prevalence in hospitalised cohorts varied between 12% and 32%, while most events occurred despite anticoagulation, and patients treated on intensive care units had a higher risk (Table 3).³⁴Birkeland K, Zimmer R, Kimchi A, Kedan I. Venous Thromboembolism in Hospitalized COVID-19 Patients: Systematic Review. Interact J Med Res 2020;9:e22768. , ³⁵Chi G, Lee JJ, Jamil A, Gunnam V, Najafi H, Memar Montazerin S, et al. Venous Thromboembolism among Hospitalized Patients with COVID-19 Undergoing Thromboprophylaxis: A Systematic Review and Meta-Analysis. J Clin Med 2020;9. , ³⁶Kollias A, Kyriakoulis KG, Lagou S, Kontopantelis E, Stergiou GS, Syrigos K. Venous thromboembolism in COVID-19: A systematic review and meta-analysis. Vasc Med 2021;26:415-25. ,³⁷Liu Y, Cai J, Wang C, Jin J, Qu L. A systematic review and meta-analysis of incidence, prognosis, and laboratory indicators of venous thromboembolism in hospitalized patients with coronavirus disease 2019. J Vasc Surg Venous Lymphat Disord 2021;9:1099-111.e6. ,³⁸Malas MB, Naazie IN, Elsayed N, Mathlouthi A, Marmor R, Clary B. Thromboembolism risk of COVID-19 is high and associated with a higher risk of mortality: A systematic review and meta-analysis. EClinicalMedicine 2020;29:100639. ,³⁹Nopp S, Moik F, Jilma B, Pabinger I, Ay C. Risk of venous thromboembolism in patients with COVID-19: A systematic review and meta-analysis. Res Pract Thromb Haemost 2020;4:1178-91. ,⁴⁰Tan BK, Mainbourg S, Friggeri A, Bertoletti L, Douplat M, Dargaud Y, et al. Arterial and venous thromboembolism in COVID-19: a study-level meta-analysis. Thorax 2021;76:970-79. ,⁴¹Tufano A, Rendina D, Abate V, Casoria A, Marra A, Buonanno P, et al. Venous Thromboembolism in COVID-19 Compared to Non-COVID-19 Cohorts: A Systematic Review with Meta-Analysis. J Clin Med 2021;10.

Adding to the increasing evidence base, results from an epidemiological cohort study including mostly non-severely affected patients with confirmed SARS-CoV-2 infection were recently published. The 443 study participants underwent a compression ultrasound of both common femoral veins, a median 9.6 months after the first positive Covid-19 test. When compared with a matched healthy cohort, non-compressible femoral veins were substantially more frequent after SARS-CoV-2 infection (odds ratio 2.68, adjusted p-value<0.001).⁴²Petersen EL, Goßling A, Adam G, Aepfelbacher M, Behrendt C-A, Cavus E, et al. Multi-organ assessment in mainly non-hospitalized individuals after SARS-CoV-2 infection: the Hamburg City Health Study COVID programme. Eur Heart J  2022;In Press.

In March 2020, the International Society of Thrombosis and Haemostasis (ISTH) published interim guidance on recognition and management of coagulopathy in COVID-19.¹Thachil J, Tang N, Gando S, Falanga A, Cattaneo M, Levi M, et al. ISTH interim guidance on recognition and management of coagulopathy in COVID-19. J Thromb Haemost 2020;18:1023-26.  Due to the lack of high-level comparative evidence, the only recommendation (weak) concerning antithrombotic therapies concerned prophylactic low molecular weight heparin (LMWH), which should be considered in all patients (including non-critically ill) who require hospital admission for COVID-19 infection, in the absence of any contraindications.²Thachil J, Tang N, Gando S, Falanga A, Cattaneo M, Levi M, et al. ISTH interim guidance on recognition and management of coagulopathy in COVID-19. J Thromb Haemost 2020;18:1023-26.  In 2020 and 2021, other guidelines and consensus documents were published by various societies.³Moores LK, Tritschler T, Brosnahan S, Carrier M, Collen JF, Doerschug K, et al. Prevention, Diagnosis, and Treatment of VTE in Patients With Coronavirus Disease 2019: CHEST Guideline and Expert Panel Report. Chest 2020;158:1143-63. ,⁴Cuker A, Tseng EK, Nieuwlaat R, Angchaisuksiri P, Blair C, Dane K, et al. American Society of Hematology 2021 guidelines on the use of anticoagulation for thromboprophylaxis in patients with COVID-19. Blood Adv 2021;5:872-88. ,⁵Barnes GD, Burnett A, Allen A, Blumenstein M, Clark NP, Cuker A, et al. Thromboembolism and anticoagulant therapy during the COVID-19 pandemic: interim clinical guidance from the anticoagulation forum. J Thromb Thrombolysis 2020;50:72-81. ,⁶Spyropoulos AC, Levy JH, Ageno W, Connors JM, Hunt BJ, Iba T, et al. Scientific and Standardization Committee communication: Clinical guidance on the diagnosis, prevention, and treatment of venous thromboembolism in hospitalized patients with COVID-19. J Thromb Haemost 2020;18:1859-65.    More recently, the European Society for Vascular Surgery (ESVS) clinical practice guidelines on the management of ALI were updated in light of the ongoing pandemic. A scoping review of the existing and rapidly changing literature was conducted to discuss if changes of clinical practice may be necessary.⁷Jongkind V, Earnshaw JJ, Bastos Gonçalves F, Cochennec F, Debus ES, Hinchliffe R, et al. Update of the European Society for Vascular Surgery (ESVS) 2020 Clinical Practice Guidelines on the Management of Acute Limb Ischaemia in Light of the COVID-19 Pandemic, Based on a Scoping Review of the Literature. European Journal of Vascular and Endovascular Surgery. , ⁸Björck M, Earnshaw JJ, Acosta S, Bastos Gonçalves F, Cochennec F, Debus ES, et al. Editor’s Choice – European Society for Vascular Surgery (ESVS) 2020 Clinical Practice Guidelines on the Management of Acute Limb Ischaemia. Eur J Vasc Endovasc Surg 2020;59:173-218. .  Amongst others, the question was raised by the authors whether heparin should be administered as initial management.  A statistically significant increased odds for venous thromboembolism due to COVID-19-related coagulopathy is often characterised by elevations in fibrinogen, D-dimer levels, and prolongation of PT/aPTT.⁹Thachil J, Tang N, Gando S, Falanga A, Cattaneo M, Levi M, et al. ISTH interim guidance on recognition and management of coagulopathy in COVID-19. J Thromb Haemost 2020;18:1023-26.  Besides thromboembolic events in larger vessels, microthrombosis was also suggested to play an important role in organ dysfunction.¹⁰Thachil J, Tang N, Gando S, Falanga A, Cattaneo M, Levi M, et al. ISTH interim guidance on recognition and management of coagulopathy in COVID-19. J Thromb Haemost 2020;18:1023-26. , ¹¹Klok FA, Kruip M, van der Meer NJM, Arbous MS, Gommers D, Kant KM, et al. Incidence of thrombotic complications in critically ill ICU patients with COVID-19. Thromb Res 2020;191:145-47. .

Randomised trials on antithrombotic strategies in patients with COVID-19

In an open-label, multicentre, randomised controlled trial at 31 centres in Brazil, patients hospitalised with COVID-19 and elevated D-dimer concentration, and who had COVID-19 symptoms for up to 14 days before randomisation, were assigned to receive either therapeutic (with either rivaroxaban, enoxaparin, or unfractionated heparin) or prophylactic anticoagulation (with either with enoxaparin or unfractionated heparin). Amongst 615 patients who were randomised, the primary efficacy outcome (time to death, duration of hospitalisation, or duration of supplemental oxygen until day 30) was not different between patients assigned therapeutic or prophylactic anticoagulation. Major or clinically relevant non-major bleeding through 30 days was significantly more frequent in the therapeutic arm (8% vs. 2%, relative risk 3.64, p=0.0010).¹²Lopes RD, de Barros ESPGM, Furtado RHM, Macedo AVS, Bronhara B, Damiani LP, et al. Therapeutic versus prophylactic anticoagulation for patients admitted to hospital with COVID-19 and elevated D-dimer concentration (ACTION): an open-label, multicentre, randomised, controlled trial. Lancet 2021;397:2253-63.  These findings were in line with another multicentre randomised controlled trial, where 600 SARS-CoV-2 positive patients admitted to an intensive care unit were randomised to receive either intermediate-dose vs. standard prophylactic dose enoxaparin for 30 days. The trial did not result in a significant difference in the primary outcome of a composite of adjudicated venous or arterial thrombosis, treatment with ECMO, or mortality within 30 days, while no significant differences were seen concerning the safety outcomes.¹³Sadeghipour P, Talasaz AH, Rashidi F, Sharif-Kashani B, Beigmohammadi MT, Farrokhpour M, et al. Effect of Intermediate-Dose vs Standard-Dose Prophylactic Anticoagulation on Thrombotic Events, Extracorporeal Membrane Oxygenation Treatment, or Mortality Among Patients With COVID-19 Admitted to the Intensive Care Unit: The INSPIRATION Randomized Clinical Trial. Jama 2021;325:1620-30.  In a multiplatform randomised controlled trial (mpRCT), a collaboration between three trial platforms (ATTACC, REMAP-CAP, ACTIV-4), therapeutic heparin was compared with usual care pharmacological prophylaxis for venous thromboembolism. Patients who required therapeutic anticoagulation for other indications were excluded. Organ support-free days of treatment was used as the primary outcome, while International Society on Thrombosis and Haemostasis (ISTH) major haemorrhage was used as a safety endpoint. In January 2021, the trial discontinued enrolling patients as the preliminary trial data suggested that therapeutic anticoagulation may be beneficial in patients with both high and low D-dimers. The interim results suggested that therapeutic anticoagulation in moderately ill patients was superior to prophylactic doses. In patients requiring intensive care, full-dose anticoagulation also improved the primary efficacy endpoint, but there was also a concern for safety in terms of a higher risk of major haemorrhage (3.7% vs. 1.8%) and mortality (35.3% vs. 32.6%).

The National Institute for Health and Care Excellence (NICE) guideline published in March 2021 recommended therapeutic dose thromboprophylaxis for patients who are hospitalised but not admitted to an intensive care unit unless there are contraindications, while most other available guidelines and consensus documents recommended routine dosed thromboprophylaxis in the same setting.¹⁴Leentjens J, van Haaps TF, Wessels PF, Schutgens REG, Middeldorp S. COVID-19-associated coagulopathy and antithrombotic agents-lessons after 1 year. The Lancet. Haematology 2021;8:e524-e33.

By the end of 2021, the ongoing pandemic, which started two years ago caused by a new coronavirus had led to more than 5.2 million deaths worldwide. It is evident that COVID-19 has significant impact on both patients with vascular disease and the practice of vascular surgery. The marked incidence of venous thromboembolism especially in severely ill patients,and often despite anticoagulation, is evidence of a clinically relevant coagulopathy associated with COVID-19 infection. Interestingly, the data concerning arterial embolism were less consistent and often had relevant bias. While high-level evidence on antithrombotic therapies remains sparse, the bleeding risk associated with full prophylactic anticoagulation, considering data from two available randomised trials, do not support therapeutic but rather prophylactic anticoagulation in hospitalised patients. However, it remains to be seen whether later data  will conclude there is a role for therapeutic anticoagulation in moderately ill patients. As this pandemic is ongoing and will remain a formidable challenge in the forseeable future, it is important to gather valid data for creating hypotheses and limiting collateral damage to patients with vascular disease. Common prioritization systems such as the VASCCON may help to guide vascular practice, given there is established evidence of variations between healthcare systems and how they manage the pandemic.