COVID-19 coagulopathy in Caucasian patients

Although the pathophysiology underlying severe COVID19 remains poorly understood, accumulating data suggest that a lung-centric coagulopathy may play an important role. Elevated D-dimer levels which correlated inversely with overall survival were recently reported in Chinese cohort studies. Critically however, ethnicity has major effects on thrombotic risk, with a 3–4-fold lower risk in Chinese compared to Caucasians and a significantly higher risk in African-Americans. In this study, we investigated COVID19 coagulopathy in Caucasian patients. Our findings confirm that severe COVID19 infection is associated with a significant coagulopathy that correlates with disease severity. Importantly however, Caucasian COVID19 patients on low molecular weight heparin thromboprophylaxis rarely develop overt disseminated intravascular coagulation (DIC). In rare COVID19 cases where DIC does develop, it tends to be restricted to late-stage disease. Collectively, these data suggest that the diffuse bilateral pulmonary inflammation observed in COVID19 is associated with a novel pulmonary-specific vasculopathy termed pulmonary intravascular coagulopathy (PIC) as distinct to DIC. Given that thrombotic risk is significantly impacted by race, coupled with the accumulating evidence that coagulopathy is important in COVID19 pathogenesis, our findings raise the intriguing possibility that pulmonary vasculopathy may contribute to the unexplained differences that are beginning to emerge highlighting racial susceptibility to COVID19 mortality

Prolonged elevation of D-dimer levels in convalescent COVID-19 patients is independent of the acute phase response

Background: Persistent fatigue, breathlessness, and reduced exercise tolerance have been reported following acute COVID-19 infection. Although immuno-thrombosis has been implicated in acute COVID-19 pathogenesis, the biological mechanisms underpinning long COVID remain unknown. We hypothesized that pulmonary microvascular immuno-thrombosis may be important in this context.Methods: One hundred fifty COVID-19 patients were reviewed at St James's Hospital Dublin between May and September 2020 at a median of 80.5 (range 44-155) days after initial diagnosis. These included patients hospitalized during initial illness (n = 69) and others managed entirely as out-patients (n = 81). Clinical examination, chest x-ray, and 6-min walk tests were performed. In addition, a range of coagulation and inflammatory markers were assessed.Results: Increased D-dimer levels (>500 ng/ml) were observed in 25.3% patients up to 4 months post-SARS-CoV-2 infection. On univariate analysis, elevated convalescent D-dimers were more common in COVID-19 patients who had required hospital admission and in patients aged more than 50 years (p 90% of convalescent patients.Conclusions: Elucidating the biological mechanisms responsible for sustained D-dimer increases may be of relevance in long COVID pathogenesis and has implications for clinical management of these patients.</p