PROLONGED ANTICOAGULATION WITH RIVAROXABAN IN KLIPPEL-TRÉNAUNAY SYNDROME: A CASE REPORT WITH 7-YEAR FOLLOW-UP

Abstract

INTRODUCTION: Klippel-Trénaunay syndrome (KTS) is a rare congenital vascular malformation associated with localized intravascular coagulopathy (LIC) and elevated thromboembolic risk. Direct oral anticoagulants (DOACs) have emerged as alternatives to low-molecular-weight heparin (LMWH), but long-term safety and efficacy data remain scarce. OBJECTIVE: To report the longest documented follow-up of continuous rivaroxaban therapy for thrombotic prophylaxis in KTS. CASE REPORT: A 30-year-old female with KTS diagnosed in infancy developed first superficial vein thrombosis (SVT) at age 23. Rivaroxaban 20 mg/day was initiated but discontinued after 4 months, resulting in immediate SVT recurrence. Anticoagulation was reinstated at 20 mg/day and maintained continuously for approximately 7 years without recurrent thromboembolic events. Doppler ultrasound revealed insufficient perforating vein, low-flow venous malformation, and competent deep venous system. Severe hypermenorrhea with iron-deficiency anemia required levonorgestrel intrauterine device insertion for bleeding mitigation while preserving full-dose anticoagulation. Dose reduction to 10 mg/day was planned upon clinical stabilization. CONCLUSION: Seven years of rivaroxaban 20 mg/day without thromboembolic recurrence represents the longest follow-up reported for DOACs in KTS. Immediate SVT recurrence upon discontinuation underscores the persistent nature of LIC, supporting continuous and individualized anticoagulation in this population.