Platelet activation and coronavirus disease 2019 mortality: Insights from coagulopathy, antiplatelet therapy and inflammation.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is associated with an inflammatory cytokine burst and a prothrombotic coagulopathy. Platelets may contribute to microthrombosis, and constitute a therapeutic target in COVID-19 therapy. AIM: To assess if platelet activation influences mortality in COVID-19. METHODS: We explored two cohorts of patients with COVID-19. Cohort A included 208 ambulatory and hospitalized patients with varying clinical severities and non-COVID patients as controls, in whom plasma concentrations of the soluble platelet activation biomarkers CD40 ligand (sCD40L) and P-selectin (sP-sel) were quantified within the first 48hours following hospitalization. Cohort B was a multicentre cohort of 2878 patients initially admitted to a medical ward. In both cohorts, the primary outcome was in-hospital mortality. RESULTS: In cohort A, median circulating concentrations of sCD40L and sP-sel were only increased in the 89 critical patients compared with non-COVID controls: sP-sel 40,059 (interquartile range 26,876-54,678)pg/mL; sCD40L 1914 (interquartile range 1410-2367)pg/mL (P<0.001 for both). A strong association existed between sP-sel concentration and in-hospital mortality (Kaplan-Meier log-rank P=0.004). However, in a Cox model considering biomarkers of immunothrombosis, sP-sel was no longer associated with mortality, in contrast to coagulopathy evaluated with D-dimer concentration (hazard ratio 4.86, 95% confidence interval 1.64-12.50). Moreover, in cohort B, a Cox model adjusted for co-morbidities suggested that prehospitalization antiplatelet agents had no significant impact on in-hospital mortality (hazard ratio 1.05, 95% CI 0.80-1.37; P=0.73). CONCLUSIONS: Although we observed an association between excessive biomarkers of platelet activation and in-hospital mortality, our findings rather suggest that coagulopathy is more central in driving disease progression, which may explain why prehospitalization antiplatelet drugs were not a protective factor against mortality in our multicentre cohort.

ISTH guidelines for antithrombotic treatment in COVID-19.

Antithrombotic agents reduce risk of thromboembolism in severely ill patients. Patients with coronavirus disease 2019 (COVID-19) may realize additional benefits from heparins. Optimal dosing and timing of these treatments and benefits of other antithrombotic agents remain unclear. In October 2021, ISTH assembled an international panel of content experts, patient representatives, and a methodologist to develop recommendations on anticoagulants and antiplatelet agents for patients with COVID-19 in different clinical settings. We used the American College of Cardiology Foundation/American Heart Association methodology to assess level of evidence (LOE) and class of recommendation (COR). Only recommendations with LOE A or B were included. Panelists agreed on 12 recommendations: three for non-hospitalized, five for non-critically ill hospitalized, three for critically ill hospitalized, and one for post-discharge patients. Two recommendations were based on high-quality evidence, the remainder on moderate-quality evidence. Among non-critically ill patients hospitalized for COVID-19, the panel gave a strong recommendation (a) for use of prophylactic dose of low molecular weight heparin or unfractionated heparin (LMWH/UFH) (COR 1); (b) for select patients in this group, use of therapeutic dose LMWH/UFH in preference to prophylactic dose (COR 1); but (c) against the addition of an antiplatelet agent (COR 3). Weak recommendations favored (a) sulodexide in non-hospitalized patients, (b) adding an antiplatelet agent to prophylactic LMWH/UFH in select critically ill, and (c) prophylactic rivaroxaban for select patients after discharge (all COR 2b). Recommendations in this guideline are based on high-/moderate-quality evidence available through March 2022. Focused updates will incorporate future evidence supporting changes to these recommendations.

Lupus Anticoagulant Single Positivity During the Acute Phase of COVID-19 Is Not Associated With Venous Thromboembolism or In-Hospital Mortality.

OBJECTIVE: The clinical relevance of antiphospholipid antibodies (aPLs) in COVID-19 is controversial. This study was undertaken to investigate the prevalence and prognostic value of conventional and nonconventional aPLs in patients with COVID-19. METHODS: This was a multicenter, prospective observational study in a French cohort of patients hospitalized with suspected COVID-19. RESULTS: Two hundred forty-nine patients were hospitalized with suspected COVID-19, in whom COVID-19 was confirmed in 154 and not confirmed in 95. We found a significant increase in lupus anticoagulant (LAC) positivity among patients with COVID-19 compared to patients without COVID-19 (60.9% versus 23.7%; P < 0.001), while prevalence of conventional aPLs (IgG and IgM anti-ß2 -glycoprotein I and IgG and IgM anticardiolipin isotypes) and nonconventional aPLs (IgA isotype of anticardiolipin, IgA isotype of anti-ß2 -glycoprotein I, IgG and IgM isotypes of anti-phosphatidylserine/prothrombin, and IgG and IgM isotypes of antiprothrombin) was low in both groups. Patients with COVID-19 who were positive for LAC, as compared to patients with COVID-19 who were negative for LAC, had higher levels of fibrinogen (median 6.0 gm/liter [interquartile range 5.0-7.0] versus 5.3 gm/liter [interquartile range 4.3-6.4]; P = 0.028) and C-reactive protein (CRP) (median 115.5 mg/liter [interquartile range 66.0-204.8] versus 91.8 mg/liter [interquartile range 27.0-155.1]; P = 0.019). Univariate analysis did not show any association between LAC positivity and higher risks of venous thromboembolism (VTE) (odds ratio 1.02 [95% confidence interval 0.44-2.43], P = 0.95) or in-hospital mortality (odds ratio 1.80 [95% confidence interval 0.70-5.05], P = 0.24). With and without adjustment for CRP level, age, and sex, Kaplan-Meier survival curves according to LAC positivity confirmed the absence of an association with VTE or in-hospital mortality (unadjusted P = 0.64 and P = 0.26, respectively; adjusted hazard ratio 1.13 [95% confidence interval 0.48-2.60] and 1.80 [95% confidence interval 0.67-5.01], respectively). CONCLUSION: Patients with COVID-19 have an increased prevalence of LAC positivity associated with biologic markers of inflammation. However, LAC positivity at the time of hospital admission is not associated with VTE risk and/or in-hospital mortality.

Placental growth factor level in plasma predicts COVID-19 severity and in-hospital mortality.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a respiratory disease associated with vascular inflammation and endothelial injury. OBJECTIVES: To correlate circulating angiogenic markers vascular endothelial growth factor A (VEGF-A), placental growth factor (PlGF), and fibroblast growth factor 2 (FGF-2) to in-hospital mortality in COVID-19 adult patients. METHODS: Consecutive ambulatory and hospitalized patients with COVID-19 infection were enrolled. VEGF-A, PlGF, and FGF-2 were measured in each patient ≤48 h following admission. RESULTS: The study enrolled 237 patients with suspected COVID-19: 208 patients had a positive diagnostic for COVID-19, of whom 23 were mild outpatients and 185 patients hospitalized after admission. Levels of VEGF-A, PlGF, and FGF-2 significantly increase with the severity of the disease (P < .001). Using a logistic regression model, we found a significant association between the increase of FGF-2 or PlGF and mortality (odds ratio [OR] 1.11, 95% confidence interval [CI; 1.07-1.16], P < .001 for FGF-2 and OR 1.07 95% CI [1.04-1.10], P < .001 for PlGF) while no association were found for VEGF-A levels. Receiver operating characteristic curve analysis was performed and we identified PlGF above 30 pg/ml as the best predictor of in-hospital mortality in COVID-19 patients. Survival analysis for PlGF confirmed its interest for in-hospital mortality prediction, by using a Kaplan-Meier survival curve (P = .001) and a Cox proportional hazard model adjusted to age, body mass index, D-dimer, and C-reactive protein (3.23 95% CI [1.29-8.11], P = .001). CONCLUSION: Angiogenic factor PlGF is a relevant predictive factor for in-hospital mortality in COVID-19 patients. More than a biomarker, we hypothesize that PlGF blocking strategies could be a new interesting therapeutic approach in COVID-19.