Abstract Number: PB1937
Meeting: ISTH 2020 Congress
Background: Antiphospholipid syndrome (APS) is an autoimmune disease characterized by thrombotic events, pregnancy complications and the presence of persistently elevated levels of antiphospholipid antibodies (aPL). It is recommended that aPL-positive patients with previous venous or arterial thrombosis receive anticoagulant therapy with vitamin K antagonists (VKA) at a target INR of 2.0 to 3.0. Despite adequate anticoagulation, recurrent thrombosis is a well-recognized complication of APS. The optimum intensity of anticoagulation in these patients remains debatable.
Aims: To determine how often recurrence of thrombotic events happen in an APS patient population receiving prolonged anticoagulation with VKA for secondary thrombosis prevention.
Methods: We performed a retrospective chart review of all diagnosed APS patients treated with VKA that currently monitor their INR levels in our institution. Patients who were included reunited the following criteria:
1. They fulfill the revised Sapporo classification criteria;
2. Are receiving prolonged AVK therapy due to previous venous or arterial thrombosis. We investigated their history of thrombotic events and whether those events happened while receiving VKA therapy.
Results: Eighty-three patients were included with median age of 51 years old. Twenty-eight (33,7%) were men and fifty-five (66,3%) were women. Six patients (7,2%) experienced at least one thrombotic event while receiving prolonged VKA therapy – three deep vein thrombosis, two ischemic strokes and one thrombosis of mechanical tricuspid valve. Five of those patients had an INR within the therapeutic range (2-3) at the time thrombosis developed.
Conclusions: The relatively low incidence of recurrent events in this population doesn’t allow us to support a switch from the recommended moderate-intensity to high-intensity anticoagulation (INR of 3.0 to 4.0). Still, risk-stratification models are needed to identify APS patients with thrombotic events who would benefit from more aggressive antithrombotic strategies. Clear recommendations on how to manage thrombotic events despite adequate treatment are also needed.
To cite this abstract in AMA style:Sousa M, Oliveira G, Koch C. Recurrence of Thrombotic Events in Antiphospholipid Syndrome Patients Receiving Prolonged Vitamin K Antagonists Therapy [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/recurrence-of-thrombotic-events-in-antiphospholipid-syndrome-patients-receiving-prolonged-vitamin-k-antagonists-therapy/. Accessed December 6, 2021.
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