Importance of gradual induction in oral anticoagulation therapy in a patient with heparin-induced thrombocytopenia with a left ventricular assist device: a case report.

BACKGROUND: We encountered a case of a patient with heparin-induced thrombocytopenia (HIT) who developed multiple thromboses following implantable left ventricular assist device (iLVAD) implantation. We herein report this case along with a literature-based discussion on the timing of warfarin initiation for such patients.

CASE PRESENTATION: A 15-year-old boy was rushed to our hospital due to cardiogenic shock associated with multiple organ dysfunction. A detailed examination, including cardiac catheterization and right heart biopsy, provided a diagnosis of dilated cardiomyopathy, for which an iLVAD placement as a bridge to cardiac transplantation was scheduled after the transplant workup. Three days before the surgery, the patient's platelet count decreased drastically from 110,000 to 40,000/µL, suggesting HIT, and his blood sample was sent to a specialized laboratory outside our hospital. The HIT antibody test came back positive during the iLVAD implantation using heparin. Thus, we chose argatroban over heparin for postoperative anticoagulation therapy, which was initiated 6 h after the surgery. The day after surgery, the patient was successfully weaned off mechanical ventilation and extubated. Oral anticoagulation therapy with warfarin was also initiated; however, on postoperative day 2, contrast-enhanced computed tomography revealed multiple thrombi in the left iliac artery, right iliac vein, and right jugular vein. We suspected hypercoagulation associated with the initiation of warfarin, prompting us to suspend warfarin and continue anticoagulation therapy with argatroban alone. On postoperative day 8, the patient's platelet count increased to 130,000/µL despite not reaching the normal range and showed two consecutive increases; therefore, we resumed oral warfarin, concerning the efficacy of argatroban as an anticoagulant for iLVAD. Thromboembolism did not recur; the patient was discharged 50 days after the operation and is currently awaiting heart transplantation.

CONCLUSIONS: We encountered a case of HIT type II in which multiple thromboses occurred following iLVAD implantation. If HIT antibodies are detected, it is crucial to initiate argatroban monotherapy and wait to start oral anticoagulation therapy with warfarin until platelet count has improved.