The Mysterious Risk of Arterial Thrombosis With COVID-19: A Case Series of Acute Limb Ischaemia in Vaccinated Patients.

Introduction Coronavirus-19 (COVID-19) plays a vital role in viral-induced hypercoagulability through the initiation of a cytokine storm. This mechanism has been found to predispose unvaccinated patients to systemic complications including arterial thrombosis (AT) with poor 30-day amputation-free survival rates. There remains, however, little understanding regarding the incidence in patients who have received a COVID-19 vaccination. This study aims to assess the incidence, management and outcomes of vaccinated patients with COVID-19 who develop thrombotic complications to reduce amputation and direct mortality. Methods The case notes of all emergency patients with COVID-19 referred to the vascular services in a tertiary referral centre between November 2021 and April 2022 were reviewed. Patients who were unvaccinated or admitted with stroke or coronary thrombosis were excluded. The study was undertaken to measure 30-day outcomes. Results Between November 2021 and April 2022, 167,290 people tested positive for COVID-19 in Norfolk. Thirty-one patients under the vascular service had COVID-19, of which, one patient was unvaccinated. Only one vaccinated patient was referred with AT and had a positive COVID-19 result two days after admission. Above-knee amputation was performed within 30 days and he survived. Seventeen percent of patients contracted COVID-19 during their hospital admission. Conclusion The incidence of acute limb ischaemia in vaccinated patients is low; however, the 30-day outcomes remain poor. Compared to unvaccinated patients, there was a significant reduction in the presentation of AT in vaccinated patients during that timeframe, despite a higher background number of COVID-19 cases. Therefore, vaccination may minimise the risk of AT.