Abstract Number: PB0839
Meeting: ISTH 2021 Congress
Background: Heparin-induced thrombocytopenia (HIT) is a life-threatening thrombotic complication, resulting from platelet activation by antibodies against heparin/platelet factor-4 complexes. However, the contribution of the ADAMTS13 and von Willebrand factor (VWF) to the disease outcomes in hospitalized patients with suspected HIT is not known.
Aims: To determine plasma levels and clinical significance of ADAMTS13 activity, VWF antigen and activity in hospitalized patients with suspected HIT.
Methods: 261 hospitalized patients with suspected HIT at the University of Alabama at Birmingham between 2012 and 2019 were retrospectively enrolled for testing their plasma levels of ADAMTS13 activity, VWF antigen, and VWF activity.
Results: Of 261 cases, 87 (33.3%) were positive for enzyme immunoassay (EIA+) and 174 (66.7%) were EIA-. Of 87 EIA+ cases, 31 (35.6%) were positive for serotonin-releasing assay (SRA+) but 56 (64.4%) were SRA-. Comparing with those in healthy controls, plasma ADAMTS13 activity was significantly lower (p<0.001) but plasma VWF antigen and activity (p<0.0001) were significantly higher in all patients with suspected HIT. No statistically significant difference was detected among three groups in plasma ADAMTS13 activity, VWF antigen, and activity. Low plasma ADAMTS13 activity (<50th percentile) was highly predictive for a 90-day mortality rate (p<0.0001). The factors associated with low ADAMTS13 activity were platelets count fall >= 50%, pulmonary embolism, sepsis, and heart failure (p<0.001). Among those with HIT, the percentage of thrombotic events and low ADAMTS13 activity was higher than that without HIT (p=0.035) but such a difference was not detected in patients without HIT (p=0.239).
Conclusions: These results demonstrate that relative deficiency of plasma ADAMTS13 activity in hospitalized patients with suspected HIT is prevalent, and such relative deficiency of plasma ADAMTS13 may contribute to thrombotic complications and in-hospital mortality in these patients.
To cite this abstract in AMA style:Chan M, Zheng XL. Low Plasma ADAMTS13 Activity Contributes to Increased Mortality Rate in Hospitalized Patients with Suspected Heparin-induced Thrombocytopenia [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/low-plasma-adamts13-activity-contributes-to-increased-mortality-rate-in-hospitalized-patients-with-suspected-heparin-induced-thrombocytopenia/. Accessed August 9, 2022.
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