Adjunct Immune Globulin for Vaccine-Induced Immune Thrombotic Thrombocytopenia.

The use of high-dose intravenous immune globulin (IVIG) plus anticoagulation is recommended for the treatment of vaccine-induced immune thrombotic thrombocytopenia (VITT), a rare side effect of adenoviral vector vaccines against coronavirus disease 2019 (Covid-19). We describe the response to IVIG therapy in three of the first patients in whom VITT was identified in Canada after the receipt of the ChAdOx1 nCoV-19 vaccine. The patients were between the ages of 63 and 72 years; one was female. At the time of this report, Canada had restricted the use of the ChAdOx1 nCoV-19 vaccine to persons who were 55 years of age or older on the basis of reports that VITT had occurred primarily in younger persons. Two of the patients in our study presented with limb-artery thrombosis; the third had cerebral venous and arterial thrombosis. Variable patterns of serum-induced platelet activation were observed in response to heparin and platelet factor 4 (PF4), indicating the heterogeneity of the manifestations of VITT in serum. After the initiation of IVIG, reduced antibody-induced platelet activation in serum was seen in all three patients. (Funded by the Canadian Institutes of Health Research.).

Management of bleeding complications in patients with cancer on DOACs.

There has been a concern that major bleeding events (MBE) on direct-acting oral anticoagulants (DOACs) will be more difficult to manage than on vitamin K antagonists. Patients with cancer and DOAC-associated bleeding may be even more of a challenge to manage. We therefore reviewed the literature on bleeding in patients with cancer on DOACs. In addition, we performed an analysis of individual patient data from 5 phase III trials on treatment with dabigatran with focus on those with cancer. In 6 randomized trials the risk of MBE in patients with cancer was similar on treatment with DOACs compared to vitamin K antagonists. Bleeding was in the majority of patients managed with supportive therapy alone. In the individual patient data analysis there were no significant differences in use of hemostatic products, transfusion of red cells, effectiveness of management, bleeding-related mortality or 30-day all-cause mortality between patients with cancer treated with dabigatran or with warfarin. Local hemostatic therapy, including resection of the cancer site was more common in patients with gastrointestinal bleeding with cancer than among those without cancer. We conclude that management of bleeding in patients with cancer and on a DOAC does not pose a greater challenge than management of bleeding in patients without cancer.