key: cord-0980853-7n9zsh6w
authors: Rostami, Mehrdad; Mansouritorghabeh, Hassan; Parsa-Kondelaji, Mohammad
title: High levels of Von Willebrand factor markers in COVID-19: a systematic review and meta-analysis
date: 2021-11-06
journal: Clin Exp Med
DOI: 10.1007/s10238-021-00769-x
sha: 14326244648d2626555b56e90f5efefef9da5e68
doc_id: 980853
cord_uid: 7n9zsh6w

The SARS-CoV-2 virus has spread to all corners of the world. Thrombosis is the cause of organ failure and subsequent death in COVID-19. The pathophysiology of thrombosis in COVID-19 needs to be further explored to shed light on its downside. For this reason, this meta-analysis of Von Willebrand Factor profile (VWF: Ag, VWF: activity, VWF: RCo), ADAMTS-13, and factor VIII levels in COVID-19 was performed. To obtain data on the status of the aforementioned hemostatic factors, a systematic literature review and meta-analysis were performed on COVID-19. After reviewing the evaluation of 348 papers, 28 papers included in the meta-analysis, which was performed using STATA. The analysis showed an increase in VWF: Ag levels in COVID‐19 patients. VWF: Ac was higher in all COVID-19 patients, while it was lower in the COVID‐19 ICU patients. The pooled mean of VWF: RCO in all patients with COVID-19 was 307.94%. In subgroup analysis, VWF: RCO was significantly higher in ICU patients than in all COVID-19 patients. The pooled mean of ADAMTS-13 activity was 62.47%, and 58.42% in ICU patients. The pooled mean of factor VIII level was 275.8%, which was significantly higher in ICU patients with COVID-19 than all patients with COVID-19. Levels of VWF: Ag, VWF: activity, VWF: ristocetin, and factor VIII are increased in patients with COVID-19. The elevated levels in ICU patients with COVID-19 suggest that these markers may have prognostic value in determining the severity of COVID-19. New therapeutic programs can be developed as a result.

COVID-19 has led to severe social and economic stress worldwide [1] . It is the greatest challenge to world health. It has resulted in a large number of deaths around the globe (4,470,969 deaths by 28 August, 2021) [2] . Although the majority of patients suffering from with SARS-CoV-2 are asymptomatic or have mild to moderate symptoms, a proportion of patients develop a severe form of the infection and die. High age, obesity, hypertension, diabetes, and cardiovascular disease increase the risk of death [3] [4] [5] [6] [7] . Diffuse alveolar damage and disseminated intravascular coagulation (DIC) seem to be the main cause of death. Microthrombi are common clinical presentation in COVID-19, with an incidence of 91.3% in deceased patients of COVID-19 [8] . Microvascular thrombosis, venous thromboembolic disease, and stroke are all examples of thrombosis that can lead to embolism in multiple organs and subsequent failure. Therefore, thrombosis prevention techniques are critical in the treatment of COVID-19 [9] . Although there is increasing evidence of endothelial dysfunction and hypercoagulability in COVID-19 [10] [11] [12] [13] . The underlying molecular mechanisms of thrombosis development in COVID-19 remain unknown. Elevated D-dimer levels are the most commonly detected coagulation abnormality in COVID-19 [14] . In severe COVID-19, elevated fibrinogen levels have been found to present a prothrombotic state that leads to thrombosis and is a predictor of mortality [15] . The transmembrane protein angiotensin-converting enzyme 2 (ACE2) allows SARS-CoV-2 to invade alveolar epithelial cells as well as endothelial cells in arteries and veins. This invasion may be accompanied by inflammation of endothelial cell damage and inflammation. Endothelial cells are a source of Weibel-Palade storage bodies that release prothrombotic mediators such as von Willebrand factor (VWF) and coagulation factor VIII [9] . VWF is both an inflammatory marker and a prognostic marker for endothelial dysfunction. Following infection of epithelial cells with SARS-CoV-2, the activated cell upregulate adhesion molecules and VWF, are upregulated in activated cells, leading to leukocyte recruitment, platelet activation, and activation of the complement system [16, 17] . Hepatic and endothelial cells secrete ADAMTS-13, a disntegrin and metalloprotease with a thrombospondin type 1 motif. It cleaves ultralarge multimers of VWF, reduces the extent of thrombogenicity of VWF and restores equilibrium in the hemostasis system [12, 13] . Decreased ADAMTS-13 levels have been associated with severe and potentially fatal thrombosis [18] . Acquired deficiency of ADAMTS-13 can lead to systemic diseases such as sepsis and inflammation [19, 20] . Therefore, it is plausible that COVID-19 is associated with increased thrombogenicity of VWF molecules [21] . Since ADAMTS-13 level plays an important role in the development of thrombosis, it is considered a predictor of mortality in COVID-19 patients [22] .

It seems that the thrombotic consequences of COVID-19 occur over a long period of time. Thrombelastometric results in survivors of severe COVID-19 patients showed that the state of hypercoagulability may persist for up to three to four months after ICU discharge [23] .

The aim of this systematic review and meta-analysis is to summarize the most current information on VWF profile (VWF: Ag, VWF: activity, VWF: RCo), factor VIII level, and ADAMTS-13 in COVID-19 patients.

A systematic literature search was conducted in PubMed, Scopus, and Web of Science on March 15, 2021. The aim was to find relevant papers investigating Von Willebrand Factor profile, and factor VIII levels in COVID-19 patients. The following keywords were used as part of the search strategy in each database: "von Willebrand Factor" OR "von Willebrand" OR "VWF" OR "Willebrand Protein" OR "von Willebrand factor activity" OR "von Willebrand: Ag" OR "VWF: ag" OR "VWF: antigen" OR "von Willebrand factor ristocetin" OR "VWF: RCO" OR "Factor VIIIR-Ag" OR "AHF" OR "anti-hemophilic factor" AND "COVID-19" OR "SARS-CoV-2". On March 15, 2021, two independent authors (M R and M P) conducted a search and entered all papers into the EndNote X7 reference manager software to screen and remove duplicates.

The following inclusion criteria were used in this metaanalysis: Articles written in English and articles examining VWF levels in COVID-19 patients. Review articles, case reports, conference articles, experimental studies or studies in animal categories, and studies with insufficient data were among the exclusion criteria used in the article search.

Two reviewers (M R and M P) independently extracted data from the final included studies to minimize bias. First author name, year of publication, country, number of patients, age and sex distribution of patients, level of VWF: Ag, level of VWF: Ac, VWF: RCO, ADAMTS-13 activity and factor VIII, if reported. The Joanna Briggs Institute (JBI) Appraisal Tool was used to determine the quality of included studies.

Extracted data are reported as mean standard deviation (SD) with 95% confidence intervals (CI). Data from articles reported as median and mean ± SD were estimated with online software using the methods described by Luo et al. [24] and Wan et al. [25] . The Stata v14.0 programme (College Station, Texas, USA) was used for all statistical analyses. In interpreting the data, a two-sided P-value of less than 0.05 was considered statistically significant. The I2 test assessed heterogeneity when heterogeneity was statistically significant (I2 > 50%). A random-effects model was used to account for within-study and between-study variances. Funnel plot and Begg's test were used to assess publication bias.

The protocol for screening studies is shown in Fig. 1 . The literature search retrieved 348 articles, including 99, 170, and 79 from PubMed, Scopus, and web of Science databases, respectively. After removing duplicates, 215 publications remained. One hundred forty-eight articles were removed from the list because they were review articles or case reports or because they had unrelated titles. After this step, 67 articles were selected for full-text review, and 28 articles were included in the systematic review and meta-analysis [12, 22, . A total of 1943 patients were analyzed in the final 28 studies used for the meta-analysis. Table 1 summarized the characteristics of the chosen studies and the characteristics of the COVID-19 patients. These studies were published between April 2020 and March 2021.

Plasma levels of VWF panel (VWF: Ag, VWF: AC, VWF: RCO), ADAMTS-13, and F VIII in patients with COVID-19 in the last studies examined were analyzed. Table 2 summarized all data in detail.

There were 1943 COVID-19 patients whose data from 28 papers were analyzed for the meta-analysis. Due to the high heterogeneity between studies (I2 = 92.66%, p = 0.00), the random-effects model was used to determine the pooled mean of VWF: Ag. For all patients, VWF:Ag was 366.55% (95% CI: 341.04-392.06, normal range: 60-150%), as shown in Fig. 2 Fig. 2 , the difference between the subgroups was not significant. (Fig. 4) .

A total of 12 papers with 859 COVID-19 patients were included in the meta-analysis. A high heterogeneity was found between studies (I2 = 95%, p = 0.00). Consequently, the random-effects model was used for the analysis, which showed that the pooled mean of ADAMTS-13 activity in (Fig. 6 ).

A plotted Begg's Funnel plot for VWF: Ag levels showed that the p-value of Begg's test was 0.342 (Fig. 7) . The Begg's test for VWF: Ag showed that there was no stable evidence of publication bias in the meta-analysis.

The findings of the current meta-analysis revealed that plasma levels of the VWF profile (VWF: Ag, VWF: Ac, and VWF: RCo) are increased in patients with COVID-19. The levels of these markers are higher in ICU patients than in all COVID-19 patients, with the exception of VWF: Ac. These findings may explain why VWF is involved in the development of thrombosis in COVID-19. VWF: Ac levels were lower in ICU patients than in all COVID-19 patients, is because the adhesive properties of VWF depend on the size of the multimers, which are typically between 5000 and 10,000 KDa. The HMWM with a size of 5000-10,000 KDa are more active in the interaction between platelet receptors and collagen, therefore they are more thrombogenic in shear stress [52] . On the other hand, VWF is the carrier of factor VIII in plasma. It protects factor VIII from accelerated clearance and thus increases the half-life of factor VIII [53, . The plasma levels of FVIII in COVID-19 patients were shown to be increased in this meta-analysis. Compared with all COVID-19 patients, the factor VIII levels were statistically higher in ICU patients with COVID-19. Elevated plasma FVIII levels can be considered as a thrombogenic factor.

According to the radiological findings, pulmonary embolism (PE) may differ from conventional PE in patients with COVID-19. It seems that there are more local in situ immunothrombosis in COVID-19 than typical conventional venous thrombosis [51] . Therefore, the pathophysiology of thrombosis in COVID-19 remains to be thoroughly investigated.

In COVID-19, certain potential players seems to be involved in the interplay between coagulation system's activation and inflammation. Thus, several biomarkers in COVID-19 have been proposed as predictors of COVI-19 severity [52] .

The limitation with this meta-analysis was the concern with the method of ADAMTS-13 determination. The recruited 12 publications about ADAMTS-13 in COVID-19, researchers measured it using different methods. We presented the data in one analysis because their normal values were virtually identical.

In light of these results, it is proposed that the following topics be investigated:

(1) Analysis of VWF multimers in patients with COVID-19 in different type of COVID-19 (mild, moderate, and severe). While there are no ultra large VWF in plasma of healthy people due to rapid proteolysis by ADAMTS-13 function [55] . In patients with deficiency or lack of ADAMTS-13, accumulation of ultra large VWF is observed on the surface of endothelial cells and in plasma. Interestingly, the obtained results show that high VWF levels were associated with lower ADAMTS13 levels, suggesting an imbalance between the increased production of this highly thrombogenic protein and a relative decrease in the enzyme responsible for its removal. There is a gap in the literature 

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