UNASSIGNED: Heparin-induced thrombocytopenia (HIT) is an immune-mediated complication that occurs in a small percentage of patients exposed to heparin. Concerns of HIT are particularly high in patients undergoing cardiac procedures requiring cardiopulmonary bypass, as they are exposed to high doses of heparin intraoperatively. Our aim was to identify and assess the hospital courses of patients who were diagnosed with HIT during readmission following cardiac surgery.
UNASSIGNED: A retrospective review of patients who underwent open cardiac surgical procedures from June 2017 through October 2019 was performed. Of these, we identified patients who were newly diagnosed with HIT upon readmission. HIT positivity was defined as a positive anti-PF4 antibody screening test, plus a positive serotonin release assay.
UNASSIGNED: Of the 2496 patients identified, 13 patients were HIT positive on index admission and were excluded. Of the remaining 2483 patients, 351 were readmitted within 30 days. Six were newly diagnosed with HIT during readmission, 5 of whom presented with thrombotic complications. One patient was readmitted with thrombocytopenia and was started on argatroban; the remaining 5 did not have a significantly lower platelet count on readmission. Of the 12 patients readmitted for venous thromboembolism, 4 tested positive for HIT.
UNASSIGNED: HIT can have a delayed appearance following open heart surgery. Venous thromboembolism appears to be a significant indicator for HIT during readmission, even in the absence of thrombocytopenia. This may support the use of non-heparin anticoagulation for cardiac surgery patients readmitted with thromboembolism until HIT status is determined.

We report the case of a 35-year-old pregnant woman (gravida 3, para 1) with antithrombin deficiency who was successfully treated with apixaban. She had a history of heparin-induced thrombocytopenia and venous thromboembolic events. Pregnancy was confirmed while the patient was having anticoagulant therapy for a persistent thrombus. Choice of anticoagulation during her pregnancy was limited because of her antithrombin deficiency: heparin was not an option because of her history of heparin-induced thrombocytopenia; antithrombin-dependent anticoagulant drugs were not an option because of her antithrombin deficiency, and she preferred outpatient management. Despite the fact that there are no reports of its use in pregnant women, we selected apixaban (10 mg/day), a direct Xa inhibitor, as the best solution. No progression of thrombus was noted during the pregnancy. The newborn baby had no external congenital anomalies, intracranial hemorrhage, or bleeding tendency. Thus, apixaban may be a candidate for anticoagulant therapy in pregnant women with a history of venous thromboembolic events and heparin-induced thrombocytopenia.