Abstract Number: PB/CO03
Meeting: ISTH 2020 Congress
Background: Coronavirus Disease 2019 (COVID-19) is Characterized by a Hypercoagulable Status and Massive Inflammation in its Most Severe Forms, with Evidence of Elevated von Willebrand Factor (VWF)
Aims: To investigate the role of VWF and ADAMTS13 in COVID-19.
Methods: We performed a cross-sectional study of 50 COVID-19 patients referred to Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan (Italy), between March and mid-April 2020. Patients were stratified by admission to three different intensity of care units: low intensive care, requiring high-flow nasal cannula oxygen therapy (n=14); intermediate sub-intensive care, requiring continuous positive airway pressure devices (n=17); high intensive care, requiring intubation and mechanical ventilation (n=19). VWF antigen (VWF:Ag) and ristocetin-cofactor activity (VWF:RCo) were measured using HemosIL® commercial kits on an ACL TOP 700 analyzer (Werfen, USA). VWF multimers were evaluated with the Hydragel 11 von Willebrand multimers kit (Sebia, France). ADAMTS13 activity (ADAMTS13:Act) was measured with the FRETS-VWF73 assay. Statistical analysis was performed using the Kruskal-Wallis test.
Results: VWF:Ag and VWF:RCo were increased in the vast majority of patients and associated with increasing intensity of care (Table 1). VWF:Ag increased more than VWF:RCo, so that median VWF:RCo/VWF:Ag ratios resulted similar or slightly reduced. We found a progressively lower proportion of HMW VWF multimers with increasing intensity of care, as shown by the decreased median ratio of HMW to LMW multimers. A negative association of ADAMTS13:Act with the intensity of care was observed, with median values decreasing from 82 to 62 and 55 IU/dl. The increase of VWF:Ag over the decrease of ADAMTS13:Act yielded markedly elevated VWF:Ag/ADAMTS13:Act ratios, increasing with intensive care status.
Conclusions: We found an imbalance of the VWF-ADAMTS13 axis in COVID-19 patients, with an elevated VWF:Ag/ADAMTS13:Act ratio being strongly associated with disease severity. Such imbalance further increases the hypercoagulable status promoted by COVID-19 disease and the risk of microthrombosis in these patients.
|Intensity of care|
|Low (n=14)||Intermediate (n=17)||High (n=19)||Kruskal-Wallis test p-value|
|Platelet count, x 109/l||234 (173-293)||362 (304-483)||358 (299-467)||0.021|
|VWF:Ag, IU/dl||268 (225-309)||386 (305-468)||476 (380-537)||<0.001|
|VWF:RCo, IU/dl||216 (188-262)||334 (257-407)||388 (328-438)||<0.001|
|VWF:RCo to VWF:Ag ratio||0.88 (0.76-0.93)||0.87 (0.79-0.93)||0.81 (0.79-0.85)||0.118|
|HMW to IMW VWF multimer ratio||1.50 (1.29-1.75)||1.35 (1.04-1.47)||1.28 (1.03-1.39)||0.034|
|HMW to LMW VWF multimer ratio||3.18 (2.54-3.80)||2.76 (2.33-3.38)||2.30 (1.70-3.06)||0.035|
|ADAMTS13:Act, IU/dl||82 (71-101)||62 (54-67)||55 (42-68)||0.001|
|VWF:Ag to ADAMTS13 ratio||3.42 (1.98-3.92)||6.77 (4.62-8.25)||8.33 (5.49-11.61)||<0.001|
[Table 1. Laboratory results in COVID-19 patients by intensity of care.]
To cite this abstract in AMA style:Mancini I, Baronciani L, Artoni A, Colpani P, Biganzoli M, Cozzi G, Novembrino C, Boscolo M, De Zan V, Aliberti S, Panigada M, Grasselli G, Blasi F, Peyvandi F. The prothrombotic imbalance between VWF and ADAMTS13 in COVID-19 [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/the-prothrombotic-imbalance-between-vwf-and-adamts13-in-covid-19/. Accessed October 1, 2023.
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