Antiphospholipid antibody syndrome-associated renal thrombotic microangiopathy improved not with rivaroxaban but with warfarin in a systemic lupus erythematosus patient without lupus nephritis.

A 34-year-old Japanese woman with systemic lupus erythematosus (SLE) was admitted to our hospital for exacerbation of renal dysfunction, hemolytic anemia and thrombocytopenia. Twenty-two years before admission, she was diagnosed with SLE. Eight years before, lupus anticoagulant (LAC) positivity was detected without any thrombotic findings. Fourteen months before, renal function started to worsen. Three months before, unprovoked left leg swelling appeared. She was diagnosed with deep vein thrombosis (DVT) by ultrasonography. Blood examination revealed mild anemia, thrombocytopenia, and renal dysfunction. Rivaroxaban was started after which the left leg swelling subsided. When she was referred to our hospital, LAC was positive, but hypocomplementemia nor elevation of serum anti-double-stranded DNA antibodies was detected. Renal biopsy showed acute and chronic thrombotic microangiopathy (TMA) without concurrent lupus nephritis. Brain magnetic resonance imaging showed new small multiple cerebral infarcts. Antiphospholipid antibody syndrome (APS), causing renal TMA, new cerebral infarction, and DVT was diagnosed. Rivaroxaban was changed to warfarin. Two months after admission, renal impairment improved, and the complete disappearance of DVT and brain infarcts was confirmed. This case suggests that warfarin may be more effective than direct oral anticoagulants in the treatment of APS-associated renal TMA.