番茄社区

Bivalirudin (Angiomax) worked for one of the very rare cases of blood clots with low platelets after vaccination against COVID-19, researchers reported.

The 40-year-old woman presented with a headache on the same day that the CDC and FDA hit pause on use of the Johnson & Johnson vaccine over risk of what's being dubbed vaccine-induced thrombotic thrombocytopenia (VITT) or thrombosis with thrombocytopenia syndrome (TTS).

She developed a headache, sinus pressure, myalgias, and sore throat with tonsillar exudate on day 5 post-vaccination but had no risk factors for clotting, stated R. Todd Clark, MD, MBA, of the University of Colorado School of Medicine in Aurora, and colleagues in the case report.

When she presented to the emergency department for worsening headaches, photophobia, and intermittent dizziness, she was found to have thrombocytopenia and an elevated d-dimer, but normal fibrinogen and mild elevation of the serum transaminase. While the initial assay for heparin-induced thrombocytopenia (HIT) was negative, a confirmatory ELISA test returned positive. CT imaging showed cerebral venous sinus thrombosis.

Treatment included bivalirudin at 0.15 mg/kg/hr with coagulation-based titration along with IV immune globulin and prednisone.

The patient's platelet count steadily rose from 20 x 10⁹/L at admission to 115 x 10⁹/L at discharge after 6 days in the hospital and then 182 x 10⁹/L on outpatient follow-up (day 9). Her headache resolved without clinical sequelae of thrombosis or evidence of bleeding.

Bivalirudin is fast and easily reversible, but whether it worked better than any other heparin alternative isn't clear from this single case, the researchers acknowledged.

"The CDC guidance recommended treatment with heparin alternatives, however there was no recommended alternative in the release," noted the authors.

Still, they concluded that "A provider may consider bivalirudin as an alternative to heparin in patients with suspected VITT following Ad26.COV2.S vaccination, pending more definitive research."

It's no surprise the patient did well on bivalirudin, which has plenty of literature support from use in HIT, commented hematologist Stephan Moll, MD, of the University of North Carolina at Chapel Hill.

"The patient would have done well on any of the non-heparin blood thinners, probably," he told 番茄社区. Bivalirudin "doesn't have any advantage over argatroban or fondaparinux [Arixtra] or the direct oral anticoagulants; it just is one of the tools in the non-heparin drug armamentarium," he added.

Management guidelines from the and a German group that reported a in the New England Journal of Medicine in April also recommended non-heparin anticoagulants and avoidance of platelet transfusions, since warfarin is contraindicated in acute thrombocytopenia.

However, while reasonable to avoid at this point, "heparin products may even be safe in patients," Moll noted. "A number of people reported have been treated with low-molecular weight heparin and still done well, which suggests that maybe there's a different physiology than the classical HIT."

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