Hypercoagulability in critically ill patients with COVID 19, an observational prospective study

Persistent hypofibrinolysis in severe COVID-19 associated with elevated fibrinolysis inhibitors activity

Hypercoagulability and reduced fibrinolysis are well-established complications associated with COVID-19. However, the timelines for the onset and resolution of these complications remain unclear. The aim of this study was to evaluate, in a cohort of COVID-19 patients, changes in coagulation and fibrinolytic activity through ROTEM assay at different time points during the initial 30 days following the onset of symptoms in both mild and severe cases. Blood samples were collected at five intervals after symptoms onset: 6-10 days, 11-15 days, 16-20 days, 21-25 days, and 26-30 days. In addition, fibrinogen, plasminogen, PAI-1, and alpha 2-antiplasmin activities were determined. Out of 85 participants, 71% had mild COVID-19. Twenty uninfected individuals were evaluated as controls. ROTEM parameters showed a hypercoagulable state among mild COVID-19 patients beginning in the second week of symptoms onset, with a trend towards reversal after the third week of symptoms. In severe COVID-19 cases, hypercoagulability was observed since the first few days of symptoms, with a tendency towards reversal after the fourth week of symptoms onset. A hypofibrinolytic state was identified in severe COVID-19 patients from early stages and persisted even after 30 days of symptoms. Elevated activity of PAI-1 and alpha 2-antiplasmin was also detected in severe COVID-19 patients. In conclusion, both mild and severe cases of COVID-19 exhibited transient hypercoagulability, reverted by the end of the first month. However, severe COVID-19 cases sustain hypofibrinolysis throughout the course of the disease, which is associated with elevated activity of fibrinolysis inhibitors. Persistent hypofibrinolysis could contribute to long COVID-19 manifestations.

Mechanisms of endothelial activation, hypercoagulation and thrombosis in COVID-19: a link with diabetes mellitus

Early since the onset of the COVID-19 pandemic, the medical and scientific community were aware of extra respiratory actions of SARS-CoV-2 infection. Endothelitis, hypercoagulation, and hypofibrinolysis were identified in COVID-19 patients as subsequent responses of endothelial dysfunction. Activation of the endothelial barrier may increase the severity of the disease and contribute to long-COVID syndrome and post-COVID sequelae. Besides, it may cause alterations in primary, secondary, and tertiary hemostasis. Importantly, these responses have been highly decisive in the evolution of infected patients also diagnosed with diabetes mellitus (DM), who showed previous endothelial dysfunction. In this review, we provide an overview of the potential triggers of endothelial activation related to COVID-19 and COVID-19 under diabetic milieu. Several mechanisms are induced by both the viral particle itself and by the subsequent immune-defensive response (i.e., NF-κB/NLRP3 inflammasome pathway, vasoactive peptides, cytokine storm, NETosis, activation of the complement system). Alterations in coagulation mediators such as factor VIII, fibrin, tissue factor, the von Willebrand factor: ADAMST-13 ratio, and the kallikrein-kinin or plasminogen-plasmin systems have been reported. Moreover, an imbalance of thrombotic and thrombolytic (tPA, PAI-I, fibrinogen) factors favors hypercoagulation and hypofibrinolysis. In the context of DM, these mechanisms can be exacerbated leading to higher loss of hemostasis. However, a series of therapeutic strategies targeting the activated endothelium such as specific antibodies or inhibitors against thrombin, key cytokines, factor X, complement system, the kallikrein-kinin system or NETosis, might represent new opportunities to address this hypercoagulable state present in COVID-19 and DM. Antidiabetics may also ameliorate endothelial dysfunction, inflammation, and platelet aggregation. By improving the microvascular pathology in COVID-19 and post-COVID subjects, the associated comorbidities and the risk of mortality could be reduced.

Whole blood viscoelastic testing profile and mortality in patients hospitalized with acute COVID-19 pneumonia: A systematic review and meta-analysis

BACKGROUND

Several studies have evaluated the possible association between whole blood viscoelastic testing (VET) parameters in patients hospitalized for acute Coronavirus disease 2019 (COVID-19) pneumonia and mortality. A few studies found no significant differences between survivors and non-survivors, though other studies identified potential predictors of COVID-19-related mortality. We conducted a systematic review and meta-analysis of the literature to evaluate the possible association between standard thromboelastometry/graphy parameters and mortality in patients hospitalized for acute COVID-19 pneumonia.

METHODS

Relevant studies were searched through MEDLINE, EMBASE, and Google Scholar from their inception until 15th June 2023. We aimed to identify any study including: i) adults admitted to intensive care units (ICU) or medicine wards (MW) for acute COVID-19 pneumonia; ii) viscoelastic testing; iii) mortality.

RESULTS

We included 13 studies: nine prospective and four retrospective, 231 (30.4 %) non-survivors and 528 (69.6 %) survivors. Mortality rates ranged from 12.8 % to 67.5 %. The studies using the TEG apparatus found a significant difference in K time in the Kaolin test among survivors vs. non-survivors (mean difference [MD] 0.20, 95 % confidence interval [CI] 0.12, 0.28, I2 0%). The studies using the rotational thromboelastometry apparatus found a significant difference in CT-INTEM (MD -17.14, 95 % CI -29.23, -5.06, I2 0%) and LI60-EXTEM (MD -1.00, 95 % CI -1.00, -1.00, I2 0%) assays among survivors vs. non-survivors.

CONCLUSION

We identified no specific hypercoagulable or hypocoagulable profile associated with mortality in patients with COVID-19-related pneumonia. Large prospective studies are needed to explore the possible prognostic role of VET in this subset of patients.