key: cord-0978574-tr7pwl6k
authors: Wibowo, Arief; Pranata, Raymond; Lim, Michael Anthonius; Akbar, Mohammad Rizki; Martha, Januar Wibawa
title: Endotheliopathy Marked by High von Willebrand Factor (vWF) Antigen in COVID-19 is Associated with Poor Outcome: A Systematic Review and Meta-analysis
date: 2021-06-27
journal: Int J Infect Dis
DOI: 10.1016/j.ijid.2021.06.051
sha: 01d1f7c491e521ffc06036c858674292e5f95903
doc_id: 978574
cord_uid: tr7pwl6k

Background: In this systematic review and meta-analysis, we aimed to compare the level of von Willebrand Factor (vWF) antigen in patients with poor outcome compared to those without. Additionally, we also explored factors that may affect the difference in terms of vWF antigen between the two groups. Methods: A comprehensive literature search was performed using the PubMed, Embase, and Scopus databases from inception up until 7 April 2021. The main outcome was poor outcome, which is a composite of mortality and severe COVID-19. Results: There are 10 studies comprising of 996 patients included in this systematic review and meta-analysis. vWF antigen was higher in patients with poor outcome (standardized mean difference [SMD] 0.84 [0.45, 1.23], p<0.001; I(2): 87.3, p<0.001). Subgroup analysis on vWF antigen that uses percentage as unit (mean difference 121.6 [53.7, 189.4], p<0.001; I(2): 92.0, p<0.001). Meta-regression showed that the SMD between poor outcome and good outcome was affected by platelets (coefficient: 0.0061, p=0.001), d-dimer (coefficient: 0.0007, p=0.026), and factor VIII level (coefficient: 0.0057, p=0.031), but not by age (coefficient: -0.0610, p=0.440), gender (coefficient: 0.0135, p=0.698), obesity (coefficient: 0.0282, p=0.666), hypertension (coefficient: 0.0273, p=0.423), diabetes (coefficient: 0.0317, p=0.398), malignancy (coefficient: 0.0487, p=0.608). Conclusion: This meta-analysis showed that the level of vWF antigen was significantly higher in patients with poor outcome, signaling a marked endotheliopathy. Meta-regression showed that differences became larger as the number of platelets, d-dimer levels, and factor VIII levels increases.

Highlights  Severe COVID-19 was associated with marked endotheliopathy  vWF antigen was higher in patients with poor outcome  The strength of association was affected by platelets, d-dimer, and factor VIII

In this systematic review and meta-analysis, we aimed to compare the level of von Willebrand Factor (vWF) antigen in patients with poor outcome compared to those without. Additionally, we also explored factors that may affect the difference in terms of vWF antigen between the two groups.

A comprehensive literature search was performed using the PubMed, Embase, and Scopus databases from inception up until 7 April 2021. The main outcome was poor outcome, which is a composite of mortality and severe COVID-19.

There are 10 studies comprising of 996 patients included in this systematic review and metaanalysis. vWF antigen was higher in patients with poor outcome (standardized mean difference [SMD] 0.84 [0.45, 1.23], p<0.001; I 2 : 87.3, p<0.001). Subgroup analysis on vWF antigen that uses percentage as unit (mean difference 121. 6 [53.7, 189.4 ], p<0.001; I 2 : 92.0, p<0.001). Metaregression showed that the SMD between poor outcome and good outcome was affected by platelets (coefficient: 0.0061, p=0.001), d-dimer (coefficient: 0.0007, p=0.026), and factor VIII level (coefficient: 0.0057, p=0.031), but not by age (coefficient: -0.0610, p=0.440), gender (coefficient: 0.0135, p=0.698), obesity (coefficient: 0.0282, p=0.666), hypertension (coefficient: 0.0273, p=0.423), diabetes (coefficient: 0.0317, p=0.398), malignancy (coefficient: 0.0487, p=0.608).

This meta-analysis showed that the level of vWF antigen was significantly higher in patients with poor outcome, signaling a marked endotheliopathy. Meta-regression showed that differences became larger as the number of platelets, d-dimer levels, and factor VIII levels increases. Pranata et al., 2020a; Raymond Pranata et al., 2021c) One of the most important complications is those caused by coagulopathy. Activation of coagulation pathway and endothelial cell (EC) is a hallmark of severe COVID-19, which is consistent with high rates of venous thromboembolism (VTE), pulmonary embolism (PE), and disseminated intravascular coagulation (DIC). (Mancini et al., 2021a; Ward et al., 2021) von Willebrand Factor (vWF) is a platelet adhesive and aggregator protein which carry coagulation factor VIII produced exclusively by EC and megakaryocytes. Thus, vWF acts as marker of EC activation which is released substantially after inflammation-mediated vascular damage. (Mancini et al., 2021a) In this systematic review and meta-analysis, we aimed to compare the level of vWF antigen in patients with poor outcome compared to those without.

Additionally, we also explored factors that may affect the difference in terms of vWF antigen between the two groups.

This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta -Analyses (PRISMA) reporting guidelines. This meta-analysis is registered in PROSPERO (CRD42021247507).

All studies that met these following criteria: 1) observational prospective and retrospective studies reporting COVID-19 patients, 2) reporting vWF antigen between patients with poor outcome and good outcome, 3) reporting mortality/severity/ARDS/ need for intensive care unit or high care unit or mechanical ventilation were included All studies that met at least one of the following criteria: 1) pre-prints, 2) reviews, 3) nonresearch letters, 4) commentaries/viewpoints/editorials, and 5) Articles in language other than English were excluded

The primary outcome of this study was poor outcome, which is a composite of mortality and severity. COVID-19 was defined as severe if it met the the criteria for severe pneumonia (Metlay et al., 2019) or requires intensive/high care or mechanical ventilation.

A comprehensive literature search was performed using the PubMed, Embase, and Scopus databases with keywords "2019-nCoV" OR "SARS-CoV-2" OR "COVID-19" AND "von Willebrand" OR "vWF" OR "endothelium" up until 7 April 2021. The PubMed (MEDLINE) search strategy was ((2019-nCoV) OR (SARS-CoV-2) OR (COVID-19)) AND ((von Willebrand) OR (vWF) OR (endothelium)). The titles and abstract were screened by two independent authors after the duplicates were removed. The articles eligibility was assessed using the inclusion and exclusion criteria.

Data from eligible studies were extracted using the standardized extraction form containing author, study design, year of publication, age, gender, obesity, hypertension, diabetes, malignancy, platelets, d-dimer, factor VIII, and the primary outcome. Data extraction was performed by two independent authors and discrepancies were resolved through discussion.

The main outcome was poor outcome; the pooled effect estimates was standardized mean difference (SMD) in terms of vWF antigen between patients with and without poor outcome.

The effect estimates were reported along with its standard deviation (SDs).

Two independent authors performed risk of bias assessment using the Newcastle-Ottawa Scale (NOS) Discrepancies that arose were resolved by discussion.

This meta-analysis was performed using Stata version 16. We pooled continuous variables using the Hedges method random-effects to populate the pooled SMD in terms of Hedges's g and its standard deviations (SDs). Restricted-maximum likelihood (REML) random-effects models was used for meta-analysis regardless of heterogeneity. P-values below 0.05 indicates statistical significance. All P-values were two-tailed and statistical significance was set at ≤0.05.

Heterogeneity was assessed using the Cochran Q test and I 2 statistics in which a p-value of <0.10 or I 2 of >50% indicates significant heterogeneity. Subgroup analysis to calculate mean difference instead of SMD was performed for studies that reported vWF antigen in terms of percentage. Funnel-plot analysis was used for qualitative measurement of publication bias, followed by non-parametric trim-and-fill analysis using Run 0 estimator. Egger's test was used to assess the potential for small-study effects quantitatively. REML random effects metaregression was performed for age, gender, obesity, hypertension, diabetes, malignancy, platelets, d-dimer, and factor VIII.

There are 10 studies comprising of 996 patients included in this systematic review and metaanalysis [ Figure 1 ]. (Cugno et al., 2021; Goshua et al., 2020; De Jongh et al., 2021; Mancini et al., 2021b; von Meijenfeldt et al., 2021; Philippe et al., 2021; Rauch et al., 2020; Rodríguez Rodríguez et al., 2021; Sweeney et al., 2021; Vassiliou et al., 2021) The baseline characteristics of the included studies were presented in Table 1 . 

This meta-analysis showed that the level of vWF antigen was significantly higher in patients with poor outcome. Meta-regression showed that differences became larger as the number of platelets, d-dimer levels, and factor VIII levels increases.

Activation of coagulation pathway and EC is found in patients with severe COVID-19, which may result in VTE, PE, and DIC. (Mancini et al., 2021a; Ward et al., 2021) These biological mechanisms play a role in the pathophysiology of serious complications of COVID-19, including cardiorespiratory collapse, thrombotic and bleeding events, sepsis, multiple organ dysfunction, and death. Marked hypercoagulability is characterized by changes in various inflammatory coagulation biomarkers, including D-dimer which is a biomarker for thrombosis and an independent predictor for poor clinical outcome, fibrinogen and fibrin degradation product (FDP) which indicate blood viscosity and fibrinolysis, P-selectin which modulates interaction between EC and blood cells, and vWF which is a marker of EC damage and bleeding (when low) and thrombotic (when high). (Grobler et al., 2020; Ladikou et al., 2020; Mancini et al., 2021a) In a relatively early stage, D-dimer levels often rise while the fibrinogen values and platelet counts change over the course of the disease. (Grobler et al., 2020; Huang et al., 2020; Raymond Pranata et al., 2021e) vWF is a platelet adhesive and aggregator protein which carry coagulation factor VIII produced exclusively by EC and megakaryocytes. vWF concentration, as well as factor VIII, are often found massively elevated (more than 4 times the upper limit of normal) in COVID-19 patients, which is comparable to those admitted to the ICU with severe sepsis. (Escher et al., 2020; Grobler et al., 2020; Ladikou et al., 2020; Zachariah et al., 2020) Apart from its role in primary hemostasis, vWF is also a marker of EC activation, released substantially after inflammation-mediated vascular damage. (Mancini et al., 2021a) An increase in vWF antigen (vWF:Ag) levels is consistent with EC activation and reflect disease severity, but plasma vWF propeptide (vWFpp) is shown to be a more sensitive and specific indicator of acute EC activation due to shorter plasma half-life (~2 vs. 12 hour) and its levels are not consumed by platelet aggregation or influenced by ABO blood group. (Mancini et al., 2021a; Philippe et al., 2021; Ward et al., 2021) However, the vWFpp/vWF:Ag ratio was decreased, suggesting that reduced VWF clearance rate plays a role in increasing vWF:Ag levels in severe COVID-19. (Ward et al., 2021) vWF activity, vWF:AG, D-dimer, and factor VIII clotting activity (FVIII:C) were persistently and massively elevated while the activity of ADAMTS13 (A Disintegrin And Metalloprotease with ThromboSpondin 1 repeats, number 13) and platelet counts were relatively normal in the majority of patients with severe COVID-19, this suggests that coagulopathy may be a different form of highly prothrombotic alterations and most likely an endothelial disease. (Escher et al., 2020) Due to ultra-large size of vWF multimers (5000-10,000 kDa in size), their high levels can only be reduced by means of plasma exchange but not by hemodialysis, which removes only molecules <60 kDA in size. Since vWF molecules are cleared by macrophages, the activation of EC (depicted by increased levels of vWF) may contribute to the activation of macrophages in COVID-19. (Zachariah et al., 2020) EC that lines the blood vessels normally function to prevent pathological thrombosis. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) gains cellular entry to human cells using angiotensin converting enzyme 2 (ACE2) receptor, which is found in the EC of vari ous organs and tissues. Ward et al., 2021) EC activation in response to high shear stress and otaher inflammatory mediators resulting in the substantial release of vWF multimers into circulation, which are cleaved and can be activated by the metalloprotease ADAMTS13. (Grobler et al., 2020; Mancini et al., 2021a; Yang et al., 2020) A decrease in ADAMTS1 was seen in some COVID-19 cases, which suggests the loss of vWF cleaving protease and subsequently its activity as well as increased risk of thrombosis in patients with myocardial infarction and ischemic stroke. (Ladikou et al., 2020) Severe deficiency of ADAMTS13 (activity <10 IU/DL) indicates thrombotic thrombocytopenic purpura (TTP), a life-threatening diffuse thrombotic microangiopathy caused by the accumulation of hyperactive vWF multimers. (Escher et al., 2020; Mancini et al., 2021a; Philippe et al., 2021) Imbalance Between vWF and ADAMTS13 could lead to a prothrombotic state in inflammatory-driven conditions, as seen in sepsis and DIC. (Mancini et al., 2021a; Yang et al., 2020) Once activated, platelets can bind to the vWF via an exposed binding site for GPIbα (part of GPIb-IX-V receptor complex), initiating thrombogenic process and leading to integrin α II b3 activation and the pivotal role of the FcR-chain and FcRIIa immunoreceptor tyrosine-based activation motif (ITAM) pathway. vWF binding to the upregulated α II b3 integrin promotes platelet adhesion and aggregation and its binding to fibrinogen augments thrombus formation. (Grobler et al., 2020; Mancini et al., 2021a) αv3 integrin is the best-characterized EC receptor for vWF which relates to EC (and smooth muscle cell) adhesion, migration proliferation, differentiation and survival. These complex responses that depend on αvβ3 function include angiogenesis, vasculogenesis and vascular cell survival, as well as crucial role in inflammatory endothelial responses. (Grobler et al., 2020) vWF can bind to red blood cells under conditions such as decreased shear rates. After inflammatory damage and increased generation of reactive oxygen species (ROS). (Grobler et al., 2020) vWF is released from the Weibel-Palade body of EC, some enter into circulation while others remain bound to the EC surface. (Philippe et al., 2021) During inflammation (and oxidative stress), red blood cells may undergo eryptosis, characterized by cell shrinkage, membrane blebbing, and cell membrane scrambling. vWF mediates erythrocyte-erythrocyte linking as well as platelet-independent erythrocyte adhesion to EC, causing microvascular occlusion and interfering dynamic blood flow. (Grobler et al., 2020; Nicolay et al., 2018) Bleeding and thrombotic pathologies often occur in patients with multiple risk factors that are likely to create severe symptoms and complications. Old age, excessive body mass index (BMI), debilitating and frail conditions, and various chronic, non-communicable diseases are comorbidities associated with worse outcomes in COVID-19. (Martha et al., 2021; Raymond Pranata et al., 2021a , 2021c , 2021b Tuty Kuswardhani et al., 2020) These unfavorable conditions drives chronic and systemic inflammation even in individuals without COVID-19. Pro-inflammatory cytokine release, complement activation, and severe hypoxia can aggravate EC damage in severe COVID-19. Due to hyperinflammatory reaction in the COVID-19induced cytokine storm, various inflammatory biomarkers, including interleukin (IL), creatine kinase (CK), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), ferritin, and procalcitonin are frequently found to be elevated. (Akbar et al., 2021; Huang et al., 2020; Yonas et al., 2020) Interestingly, meta-regression analysis showed that obesity, hypertension, diabetes, and malignancy did not affect the difference in terms of vWF antigen between the two groups.

These factors are usually associated with endotheliopathy, nevertheless , the medications used in the patients in the included studies are obscure. Several long-term medications used may be beneficial in COVID-19 with comorbidities and has effect on endothelium (Lukito et al., 2020; Pranata et al., 2020b; Raymond Pranata et al., 2021d) , thus may affect the analysis.

This meta-analysis indicates that the vWF antigen level is higher in patients with severe COVID-19. Thus establishing the importance of endotheliopathy in patients with COVID-19 as the disease progresses from the pathophysiological perspective. From the clinical perspective, elevated vWF antigen signals poor prognosis. For the therapeutic purpose, the result of this study may serve as a basis for further research; for example, several s tudies indicate that the use of antiplatelet or anticoagulant was associated with improved prognosis, while the other did not. Investigating the effect of antiplatelet or anticoagulant on prognosis in patients with high vWF antigen compared to patients with low vWF antigen may explain the heterogeneity among the studies.

The studies did not report optimal cut-off points for prognostication purposes. To be more useful clinically, the cut-off points need to be determined. Additionally, most of these studies did not report the use of drugs such as aspirin, anticoagulants, nitric oxide related drugs, statins, and other medications that may affect endothelial function. These medications may affect the dynamics of vWF antigen or the outcome in these patients. Some of the included studies were cross-sectional, thus some of the events may have already occurred as the blood was drawn.

Future studies should address the optimal cut-off point for prognostic purpose and whether antiplatelet/anticoagulant affect the outcome in patients with high vWF antigen.

This meta-analysis showed that the level of vWF antigen was significantly higher in patients with poor outcome, signaling a marked endotheliopathy. Meta-regression showed that differences became larger as the number of platelets, d-dimer levels, and factor VIII levels increases.

Data are available on reasonable request 

The prognostic value of elevated creatine kinase to predict poor outcome in patients with COVID-19 -A systematic review and meta-analysis: Creatinine Kinase in COVID-19

Complement activation and endothelial perturbation parallel COVID-19 severity and activity

ADAMTS13 activity, von Willebrand factor, factor VIII and Ddimers in COVID-19 inpatients

Endotheliopathy in COVID-19-associated coagulopathy: evidence from a single-centre, cross-sectional study

d-dimer, von willebrand factor, p-selectin and their interactions with endothelial cells, platelets and erythrocytes

C-reactive protein, procalcitonin, Ddimer, and ferritin in severe coronavirus disease-2019: a meta-analysis

Vascular activation is a strong predictor of mortality in coronavirus disease 2019 patients on the ICU

Von Willebrand factor (vWF): Marker of endothelial damage and thrombotic risk in COVID-19?

Multiorgan Failure With Emphasis on Acute Kidney Injury and Severity of COVID-19: Systematic Review and Meta-Analysis

The Effect of Metformin Consumption on Mortality in Hospitalized COVID-19 patients: a systematic review and metaanalysis

The ADAMTS13-von Willebrand factor axis in COVID-19 patients

The ADAMTS13-von Willebrand factor axis in COVID-19 patients

Tricuspid annular plane systolic excursion (TAPSE)

measured by echocardiography and mortality in COVID-19: A systematic review and metaanalysis

Prothrombotic changes in patients with COVID-19 are associated with disease severity and mortality

Diagnosis and treatment of adults with community-acquired pneumonia

Cellular stress induces erythrocyte assembly on intravascular von Willebrand factor strings and promotes microangiopathy

Circulating Von Willebrand factor and high molecular weight multimers as markers of endothelial injury predict COVID-19 in-hospital mortality

Clinical frailty scale and mortality in COVID-19: A systematic review and dose-response meta-analysis: Clinical Frailty Scale in COVID-19

Diabetes and COVID-19: The 21

The Present, and The Future

Delirium and Mortality in Coronavirus Disease 2019 (COVID-19) -A Systematic Review and Meta-analysis

Delirium and Mortality in Coronavirus Disease 2019 (COVID-19) -A Systematic Review and Meta-analysis

Incidence and impact of cardiac arrhythmias in coronavirus disease 2019 (COVID-19): A systematic review and meta-analysis

Thrombocytopenia as a prognostic marker in COVID-19 patients: Diagnostic test accuracy meta-analysis

Body mass index and outcome in patients with COVID-19: A dose-response meta-analysis

The use of renin angiotensin system inhibitor on mortality in patients

A systematic review and meta-analysis

Coagulation biomarkers are independent predictors of increased oxygen requirements in COVID-19

Increased von Willebrand factor antigen and low ADAMTS13 activity are related to poor prognosis in covid-19 patients

Activity Correlates with Increased Mortality in COVID-19 Patients

Charlson comorbidity index and a composite of poor outcomes in COVID-19 patients: A systematic review and meta-analysis

ICU Admission Levels of Endothelial Biomarkers as Predictors of Mortality in Critically Ill COVID-19 Patients

Von Willebrand factor propeptide in severe coronavirus disease 2019 (COVID-19): evidence of acute and sustained 23

Weekly epidemiological update -2

Insights Into Immunothrombosis: The Interplay Among Neutrophil Extracellular Trap, von Willebrand Factor, and ADAMTS13

Elevated interleukin levels are associated with higher severity and mortality in COVID 19 -A systematic review, meta-analysis, and meta-regression

Targeting raised von Willebrand factor levels and macrophage activation in severe COVID-19: Consider low volume plasma exchange and low dose steroid