SARS-CoV-2 Virus Infection-Related Arterial Thromboembolism Leading to Critical Limb Ischemia and Amputation

COVID-19 infection has been shown to increase risk for thromboembolism. With most studies reporting mainly venous thromboembolic events, there is a lack of literature regarding the incidence of arterial thromboses in patients with COVID-19 infection. We report a dramatic case of a 55-year-old male with confirmed COVID-19 infection who presented with acute left critical limb ischemia leading to amputation as a result of thromboembolism from a distal abdominal aortic thrombus. Our case report contributes to the limited body of literature on COVID-19-related arterial thromboembolism. The patient consented to publish this case.

Differential Presentations of Arterial Thromboembolic Events Between Venous Thromboembolism and Atrial Fibrillation Patients

Objective: Atrial fibrillation (AF) and venous thromboembolism (VTE) share several risk factors related to arterial thromboembolism. No study has reported the differential contribution to arterial thromboembolic events and mortality between these two conditions in the same population. We therefore assessed the differential arterial thromboembolic events between AF and VTE.Methods: We included AF and VTE national cohorts derived from Taiwan National Health Insurance Research Database between 2001 and 2013. The eligible population was 314,861 patients in the AF cohort and 41,102 patients in the VTE cohort. The primary outcome was arterial thromboembolic events, including ischemic stroke, extracranial arterial thromboembolism (ECATE) and myocardial infarction (MI). Secondary outcomes were all-cause mortality and cardiovascular death.Results: After a 1:1 propensity matching, 32,688 patients in either group were analyzed. The risk of arterial thromboembolic events was lower in the VTE cohort than that in the AF cohort (subdistribution hazard ratio [SHR], 0.60; 95% confidence interval [CI], 0.57–0.62). The risk of ischemic stroke (SHR, 0.44; 95% CI, 0.42–0.46) and MI (SHR, 0.80; 95% CI, 0.72–0.89) were lower in the VTE cohort, while the risk of ECATE (SHR, 1.23; 95% CI, 1.14–1.33; particularly lower extremities) was higher in the VTE cohort. All-cause mortality rate was higher in the VTE cohort (HR, 1.18; 95% CI, 1.15–1.21) while the risk of cardiovascular death was lower in the VTE cohort (HR, 0.96; 95% CI, 0.93–0.995).Conclusions: Patients with AF had higher risks of arterial thromboembolic events compared to patients with VTE, despite having risk factors in common. The VTE cohort had higher risks of all-cause mortality and ECATE, particularly lower extremity events, compared to AF patients. The differential manifestations of thromboembolism sequelae and mortality between AF and VTE patients merit further investigation.

Accelerated fibrin clot degradation is associated with arterial thromboembolism in patients following venous thrombosis: a cohort study

Several lines of evidence have suggested that patients following venous thromboembolism (VTE) are at higher risk of arterial thromboembolism (ATE). Prothrombotic fibrin clot characteristics were reported in individuals with cardiovascular risk factors. We investigated whether specific fibrin clot properties measured after 3–4 months of anticoagulation characterize VTE patients with subsequent ATE. We enrolled 320 patients following VTE aged below 70 years (median age, 46). Ten patients were lost to follow-up. ATE occurred in 21 individuals after a median 54 (31–68) months during a follow-up of 87.5 months (incidence 0.94%; 95% confidence interval [CI], 0.59–1.4 per patient-year). Patients with ATE had faster fibrin clot degradation, reflected by maximum rate of D-dimer increase during plasma clot lysis induced by tissue-type plasminogen activator (D-Drate) at baseline. Clot permeability, turbidimetric variables, clot lysis time, and thrombin generation were unrelated to ATE. Univariable Cox proportional hazards analysis showed that age, diabetes, and D–Drate were risk factors for subsequent ATE. Increased D–Drate (by 0.001 mg/L/min; hazard ratio, 1.08; 95% CI 1.02–1.14) was an independent predictor of ATE after adjustment for potential confounders. Faster fibrin clot degradation at 3 months since VTE may increase the risk of ATE among VTE patients during follow-up.

Acquired autoimmune Haemophilia following SARS-CoV-2 vaccines: Dual drug effects on blood coagulation and the Scylla and Charybdis phenomenon

Vaccination against the SARS-CoV-2 may lead to immunologic reactions activating the haemostatic system and resulting in both venous and arterial thromboembolism. Aquired autoimmune Haemophilia following SARS-CoV-2 vaccines were now reported 15 to 19 days (or later) after vaccination and resolution of symptoms by adequate treatment of the immunologic reaction. From patients’ point of view, anticoagulants and SARS-CoV-2 vaccines share their capacity to induce thrombosis as well as bleeding and clinicians are subjected to Scylla and Charybdis when they treat patients not only with anticoagulants but also with SARS-CoV-2 vaccines. Careful analysis of coincidence and causality requires attention when reporting on acquired coagulation inhibitors regarding severity, treatments, duration and statistical risk.