Anticoagulant therapy for a patient with recurrent pulmonary embolism and warfarin resistance：a case report and literature review

Abstract Background Warfarin serves as a primary anticoagulant in the management of pulmonary embolism. This paper delves into the complexities of anticoagulant therapy in a patient demonstrating resistance to warfarin with recurrent pulmonary thromboembolism. Case presentation: A 62-year-old female patient was admitted due to recurrent pulmonary embolism, prompting the initiation of anticoagulant therapy. The dosage of enoxaparin was increased by 1/3 − 1/4 to address the severity of the condition. However, subsequent warfarin therapy revealed resistance, with the patient displaying homozygosity for the VKORC1-1639G > A variant and possessing CYP4F2 *3, GGCX with the wild-type CC, indicative of rapid warfarin metabolism. Detailed inquiry into lifestyle revealed habitual consumption of over 7 cups (200 mL/cup) of strong green tea daily, potentially contributing to warfarin resistance. Treatment adjustments were made, recommending a controlled warfarin dose of 12.0 mg to maintain an international normalized ratio of 2.12. Conclusions Warfarin resistance is influenced by diverse clinical factors. Accurate identification of this resistance is crucial to tailor anticoagulant therapies effectively. A personalized treatment plan, incorporating consideration of underlying comorbidities, concomitant medications, and dietary nuances, is essential. This case highlights the need for a holistic approach in managing warfarin resistance, ensuring optimal outcomes for patients.