COVID-Associated Acute Limb Ischemia During the Delta Surge And The Effect Of Vaccines

Hypercoagulability is common in SARS-CoV-2 and has been associated with arterial thrombosis leading to acute limb ischemia (ALI). Our objective was to determine the outcomes of concurrent COVID-19 infection and ALI, particularly during the Delta variant surge and the impact of vaccination status.A retrospective review was performed of patients treated at a single healthcare system between March 2020 and December 2021 for ALI and recent (14 days) COVID-19 infection or who developed ALI during hospitalization for the same disease. Patients were grouped by year as well as by pre and post Delta variant emergence in 2021 based on WHO timeline (January-May vs. June-December). Baseline demographics, imaging, interventions, and outcomes were evaluated. A control cohort of all ALI patients requiring surgical intervention for a two-year period prior to the pandemic was used for comparison. Primary outcomes were in-hospital mortality and amputation-free survival. Kaplan-Meier survival and Cox proportional hazards analysis were performed.40 acutely ischemic limbs were identified in 36 patients with COVID-19, the majority during the Delta surge (52.8%) and after the wide availability of vaccines. The rate of COVID-19 associated ALI, though low overall, nearly doubled during the Delta surge (0.37% vs. 0.20%, p-value=.09). Baseline demographics and comorbidities are summarized in Table 1. Intervention (open or endovascular revascularization vs. primary amputation) was performed on 31 limbs in 28 individuals with the remaining 8 treated with systemic anti-coagulation. Post-operative mortality was 48% and overall mortality was 50%. Major amputation following revascularization was significantly higher with COVID ALI (25% vs. 3%, p=0.006) compared to the pre-pandemic group. 30-day amputation-free survival was significantly lower (log-rank p0.001). COVID infection (aHR=6.2, p0.001) and age (HR=1.1, p=0.006) were associated with 30-day amputation in multivariate analysis. Severity of COVID infection, defined as vasopressor usage, was not associated with post-revascularization amputation. There was a higher incidence of re-thrombosis in the latter half of 2021 with the Delta surge as reintervention for recurrent ischemia of the same limb was more common than our previous experience (21% vs. 0%, p=0.55). COVID-19 associated limb ischemia occurred almost exclusively in non-vaccinated patients (92%).ALI observed with Delta appears more resistant to standard therapy. Unvaccinated status correlated highly with ALI occurrence in the setting of COVID-19 infection. Information of limb loss as a COVID complication among non-vaccinated may help to increase compliance.