T HAN1, C HAN1, Z THET1
1Department of Nephrology, Central Queensland Hospital and Health Service, Rockhampton, QLD
Background: Overall incidence of venous thormboembolism (VTE) in adult nephrotic syndorme (NS) is 25-30%. The pathophysiology of VTE in NS is complex and poorly understood. A quality study on the topic of optimal VTE prevention/treatment in patients with NS is scarce with a lack of randomized controlled trials in the subject area. Hypoalbuminemia itself can lead to altered pharmacokinetics and pharmacodynamics of medications, although this topic is infrequently considered in daily clinical practice.
Case report: A sixty year old male patient without significant comorbidities was diagnosed with pulmonary embolism (PE) when admitted with suspected acute pyelonephritis. His thrombophilia screen was negative. The patient was discharged home with highly protein bound new oral anticoagulant (NOAC;Rivaroxaban 15mg BD for 3 weeks followed by 20mg OD). Patient was compliant with his medications.. Whilst on rivaroxaban for 5 months, he had new onset unilateral renal vein thrombosis (RVT) and recurrence of bilateral PE. He was subsequently diagnosed with membranous nephropathy which was treated successfully with modified Pontecelli regime. His unilateral RVT and recurrence of bilateral PE were successfully treated with warfarin.
Conclusions: Highly protein bound NOAC may not be efficacious in NS associated VTE. Possible explanations for failure to treat or prevent VTE with NOAC include selective inhibition of coagulation cascade by NOAC and inadequate or unsustained plasma levels of highly protein bound NOAC in hypoalbuminemic state. Lack of requirement for routine drug level monitoring of NOAC is currently considered as an advantage, but it may be a major disadvantage in preventing or treating VTE in adult patients with NS.