From the Guidelines
Management of a patient with an elevated dilute Russell's viper venom time (dRVVT) typically involves anticoagulation therapy, as this test result suggests the presence of lupus anticoagulant, a type of antiphospholipid antibody associated with thrombotic risk. For patients with a confirmed positive dRVVT and a history of thrombosis, long-term anticoagulation with direct oral anticoagulants (DOACs) such as apixaban, dabigatran, edoxaban, or rivaroxaban is recommended over vitamin K antagonist (VKA) as treatment-phase anticoagulant therapy, as suggested by the 2021 guidelines for antithrombotic therapy for VTE disease 1. In patients with recurrent thrombosis despite adequate anticoagulant therapy, a switch to a different anticoagulant or addition of an antiplatelet agent may be necessary. For pregnant patients with elevated dRVVT and a history of pregnancy complications, prophylactic treatment with low-dose aspirin (81mg daily) plus prophylactic-dose low molecular weight heparin (LMWH) is typically used. In asymptomatic patients with an incidentally discovered elevated dRVVT but no history of thrombosis, observation with thromboprophylaxis during high-risk situations may be sufficient. Some key points to consider in the management of patients with elevated dRVVT include:
- Confirmation of the presence of lupus anticoagulant with repeat testing after 12 weeks, as transient elevations can occur during infections or with certain medications.
- Individualization of management based on the patient's clinical history, additional risk factors for thrombosis, and the presence of other antiphospholipid antibodies.
- Consideration of the risks and benefits of anticoagulation therapy, including the risk of bleeding and the potential for thrombotic events.
- Regular monitoring of the patient's condition and adjustment of the treatment plan as needed. The American Society of Hematology 2020 guidelines for management of venous thromboembolism also provide recommendations for the treatment of deep vein thrombosis and pulmonary embolism, including the use of thrombolytic therapy for patients with PE and hemodynamic compromise, and the use of an international normalized ratio (INR) range of 2.0 to 3.0 for patients with VTE who use a VKA for secondary prevention 1. However, the most recent and highest quality study, which is the 2021 guidelines for antithrombotic therapy for VTE disease, recommends the use of DOACs over VKA as treatment-phase anticoagulant therapy 1.
From the Research
Management of Elevated dRVVT
Elevated dilute Russell's viper venom time (dRVVT) is often associated with the presence of antiphospholipid antibodies, which can lead to thrombotic antiphospholipid syndrome (APS). The management of patients with elevated dRVVT typically involves anticoagulation therapy.
Anticoagulation Options
- Warfarin or alternative vitamin K antagonists (VKAs) are commonly used for the management of thrombotic APS 2.
- Low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) may be used in certain situations, such as during pregnancy or in patients who are refractory to VKAs 2.
- LMWH has been shown to be a safe and effective alternative to warfarin for APS patients who have not responded to or tolerated VKAs 3.
- Non-Vitamin K antagonists oral anticoagulants (NOACs) may also be considered, although their use in APS is not as well established as in other conditions such as deep vein thrombosis (DVT) 4.
Monitoring Anticoagulation
- The international normalized ratio (INR) may not be representative of anticoagulation intensity in patients with APS on warfarin due to an interaction between lupus anticoagulant and the thromboplastin reagent used in the INR determination 2.
- Venous and point-of-care INR monitoring may be used to assess anticoagulation intensity in patients with APS on warfarin 2.
- Monitoring of LMWH/UFH may involve regular assessment of anti-Xa levels 2.