Treatment of vaccine-induced immune thrombotic thrombocytopenia (VITT)

Semin Hematol. 2022 Apr;59(2):89-96. doi: 10.1053/j.seminhematol.2022.03.002. Epub 2022 Mar 7.

Abstract

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a novel prothrombotic disorder characterized by thrombosis, thrombocytopenia, and disseminated intravascular coagulation identified in hundreds of recipients of ChAdOx1 nCoV-19 (Oxford/AstraZeneca), an adenovirus vector coronavirus disease 2019 (COVID-19) vaccine. VITT resembles heparin-induced thrombocytopenia (HIT) in that patients have platelet-activating anti-platelet factor 4 antibodies; however, whereas heparin typically enhances platelet activation by HIT antibodies, VITT antibody-induced platelet activation is often inhibited in vitro by pharmacological concentrations of heparin. Further, the thrombotic complications in VITT feature much higher frequencies of atypical thrombosis, most notably cerebral vein thrombosis and splanchnic vein thrombosis, compared with HIT. In this review, we outline the treatments that have been used to manage this novel condition since its recognition in March 2021, including anticoagulation, high-dose intravenous immune globulin, therapeutic plasma exchange, corticosteroids, rituximab, and eculizumab. We discuss the controversial issue of whether heparin, which often inhibits VITT antibody-induced platelet activation, is harmful in the treatment of VITT. We also describe a case of "long VITT," describing the treatment challenges resulting from platelet-activating anti-PF4 antibodies that persisted for more than 9 months.

Keywords: Heparin; High-dose immune globulin (IVIG); Long VITT; Therapeutic plasma exchange (TPE); Vaccine-induced immune thrombotic thrombocytopenia (VITT).

Publication types

  • Case Reports
  • Review

MeSH terms

  • COVID-19 Vaccines* / adverse effects
  • COVID-19* / prevention & control
  • ChAdOx1 nCoV-19
  • Heparin / adverse effects
  • Humans
  • Platelet Factor 4
  • Purpura, Thrombocytopenic, Idiopathic* / chemically induced
  • Thrombosis* / chemically induced

Substances

  • COVID-19 Vaccines
  • Platelet Factor 4
  • Heparin
  • ChAdOx1 nCoV-19