Heparin-Induced Thrombocytopenia (HIT) in the Direct Oral Anticoagulants (DOAC) Era

Ann Vasc Surg. 2024 Nov:108:166-170. doi: 10.1016/j.avsg.2024.05.005. Epub 2024 Jun 26.

Abstract

Background: Heparin-induced thrombocytopenia (HIT) is an uncommon complication of heparin therapy with significant risk for severe morbidity and mortality. We investigated the role and outcome of direct oral anticoagulants (DOACs) for the management of HIT.

Methods: After institutional review board (IRB) approval, a retrospective review was performed identifying all patients with positive HIT serotonin-release assays between 2020 and 2022 at two hospitals. The demographic and clinical variables were collected as follows: initial anticoagulant, dosing and indication, interval before onset of HIT, thrombotic complications, platelet nadir and recovery, direct thrombin inhibitor (DTI) and DOAC usage, and clinical outcomes.

Results: 15 patients were included in the study. 8 underwent a vascular procedure, 3 had cardiac surgery, 1 patient had both and was included in both groups, and 5 patients had either noncardiac, nonvascular surgery, or no surgery. 14 patients received unfractionated heparin (93% with therapeutic dosing), and 1 received prophylactic enoxaparin prior to diagnosis of HIT. The average time to diagnosis of HIT was 10.77 days after initial anticoagulation. In-hospital mortality was 27%, related to Covid-19 infection (3/4) and intracranial hemorrhage (1/4). 40% developed thrombosis (67% venous, 33% arterial) after the diagnosis of HIT. 8/11 survivors were discharged on a DOAC. With DOAC therapy, platelet counts rebounded to an average of 265K ( ± 104.6 K) within an average of 2.3 days and 364K ( ± 273.9 K) within 30 days after initiation of a DOAC. No recurrent thrombosis occurred after DOAC administration and only one patient had persistent thrombocytopenia within 30 days.

Conclusions: Mortality and thrombosis (arterial and venous) are common complications in patients diagnosed with HIT. In patients who survive to discharge, DOACs are the most common discharge antithrombotic agent, with low rates of recurrent thrombosis and thrombocytopenia.

Publication types

  • Multicenter Study

MeSH terms

  • Administration, Oral
  • Aged
  • Aged, 80 and over
  • Anticoagulants* / administration & dosage
  • Anticoagulants* / adverse effects
  • COVID-19 / complications
  • COVID-19 / mortality
  • Female
  • Heparin* / administration & dosage
  • Heparin* / adverse effects
  • Hospital Mortality
  • Humans
  • Male
  • Middle Aged
  • Retrospective Studies
  • Risk Factors
  • Thrombocytopenia* / blood
  • Thrombocytopenia* / chemically induced
  • Thrombocytopenia* / diagnosis
  • Thrombocytopenia* / mortality
  • Time Factors
  • Treatment Outcome

Substances

  • Heparin
  • Anticoagulants