Cardiovascularmiddle twist
A 42-year-old woman has a second proximal deep vein thrombosis while taking rivaroxaban regularly for a previous unprovoked event. Her renal function is normal and dispensing records confirm adherence. Testing shows persistent lupus anticoagulant, anticardiolipin antibodies and anti-beta-2 glycoprotein I antibodies on samples 12 weeks apart. Which one of the following is the most appropriate long-term anticoagulant?