Clinical presentation:
A 68-year-old woman with a past medical history of mechanical mitral valve replacement, hypertension, diabetes, obese and chronic atrial fibrillation on chronic warfarin anticoagulation with an INR in range between 2,5 and 3,5 compliant to medical therapy presented to the emergency room complaining of fatigue, alteration of general condition and epistaxis.
Additionally, her past medical history included breast cancer diagnosed 1 year ago and the patient was treated with Doxorubicin. She had her last chemotherapy session 1 week before her symptoms. No fever, nausea, vomiting nor night sweats. Her laboratory results in the emergency room revealed a hemoglobin of 9.2 g/dl, platelet count of 10,000/mm3 and an INR of 2,3. Her serum creatinine and blood urea nitrogen were normal. Subsequently, warfarin was held, and the patient received platelets transfusion. The second day blood labs revealed a hemoglobin level of 8g/dl and a platelet count of 20000/mm3 with an INR of 1,9. Blood transfusion was also given. Patient was not in range anymore and to balance the risk of bleeding and valve thrombosis was the main issue because as known mechanical mitral valve are at high risk of thrombosis. Fondaparinux was recommended after both hematology and cardiology discussion. Drug was suggested as a bridging therapy until the patient had regain normal platelet levels. Fondaparinux was initiated on the 1st day at 7.5 mg subcutaneously once daily based on a weight of 80 kg, and a calculated creatinine clearance of 65 ml/min. Warfarin was initiated 5 days after the patient recovered from her thrombocytopenia with a normal level of 150000/mm3 for an INR goal of 2,5–3,5. Therapeutic INR was reached 4 days after where patient was receiving concomitant warfarin and fondaparinux. No signs or symptoms of bleeding or thrombosis had been exhibited. By the time fondaparinux was interpreted, patient had a therapeutic INR of 3 and remained on warfarin alone. Cardiac ultrasound was done revealing a good functional metallic mitral valve and a good LV function. No complications were seen.