The Mysterious Risk of Arterial Thrombosis With COVID-19: A Case Series and Systematic Review of Acute Limb Ischaemia

Introduction: Coronavirus disease 2019 (COVID-19) generates a cytokine storm that predisposes patients to systemic complications including arterial thrombosis (AT) and acute limb ischaemia (ALI). This study reviews our understanding of the incidence and outcomes of patients with COVID-19 who develop AT. Methods: The case notes of all emergency patients with COVID-19 referred to the vascular services between March 2020 and March 2021 were reviewed. The study was undertaken to measure 30-day outcomes. Additionally, a literature search was undertaken according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the following search terms: acute limb ischaemia OR arterial thrombosis OR thrombectomy OR embolectomy AND COVID-19. Results: During March 2020 and March 2021, 60,000 people tested positive for COVID-19 in Norfolk. A total of 33 patients were referred to the vascular services, of which 15 had AT (estimated incidence of 0.03%). Of AT patients, 93% had ALI. Fourteen locations of AT were identified. Of ATs, 36% were infrainguinal. The 30-day mortality was 60%. Three patients underwent surgery: two embolectomies (one requiring subsequent below-knee amputation (BKA) and the other died) and one primary BKA requiring subsequent above-knee amputation. The 30-day amputation-free survival (AFS) rate was 29%. The literature search identified 361 studies prior to a thorough full-text review. Nine case series were included with more than 10 participants each. The incidence of AT was reported as high as 15%. In-hospital mortality was 40%, with a significant proportion undergoing amputation or palliative care. Approximately a third of patients undergoing revascularisation subsequently re-occluded. AFS remained as low as 25%. Conclusion: The incidence of AT within the vascular surgery territory in COVID-19 patients is low; however, it is associated with poor 30-day AFS. A computed tomography angiography protocol including the entire major vessels may be indicated in COVID-19 patients.