Background. The problem of hemostasis system pathology in patients with AL amyloidosis (AL-A) is of great practical importance. Currently, there are no recommendations concerning indications and methods of prevention of thrombotic complications.Aim. To study the main parameters of blood coagulation system in patients with AL amyloidosis, to determine the indications for anticoagulant therapy, to evaluate the efficacy and safety of apixaban prophylactic use during antitumor therapy.Materials and methods. A prospective single-center study included 65 patients with newly diagnosed systemic AL amyloidosis. The median age was 58 (34–74) years. Induction therapy according to the program BorCyDex (bortezomib, cyclophosphamide, dexamethasone) was given to 59 (90 %) patients, of which 5 patients received the combination of BorCyDex with a monoclonal antibody to CD38 – daratumumab. The remaining 6 (10 %) patients were treated with melphalan. Patients with laboratory signs of hypercoagulability or thrombotic complications were treated with apixaban in therapeutic or prophylactic dose. Indications for apixaban therapy in therapeutic dose (10 mg/day): atrial fibrillation, arterial thrombosis or pulmonary embolism less than 1 year ago. Indications for apixaban therapy in prophylactic dose (5 mg/day) were considered the presence of one or more factors: hypoalbuminemia less than 20 g/L; increase in D-dimer level more than 500 ng/mL without instrumentally verified arterial or venous thrombosis; increase in D-dimer level more than 500 ng/mL within 3 months after resolved episode of thrombosis; increase in fibrinogen level more than 4 g/L; increase in FVIII activity more than 150 %. When two or more factors were present, an antiplatelet agent (acetylsacylicylic acid) was added to apixaban therapy. The follow-up period was 4–9 months (median 6 months).Results. Before the start of antitumor therapy, thrombotic complications were diagnosed in 15 (23 %), bleeding – in 3 (5 %) patients. Hemostasis study revealed an increase in one or more laboratory parameters reflecting hypercoagulability in 92 % of patients. Increase in fibrinogen level was found in 70 %, D-dimer – in 72 %, FVIII activity – in 92 % of patients. 3 (5 %) patients received a therapeutic dose of apixaban, 58 (89 %) patients ‒ a prophylactic dose. Therapy with apixaban and antiplatelet agent was performed in 10 (15 %) patients. During the follow-up 3 patients developed complications related to hemostasis system disorders: 1 (2 %) patient had thrombosis (ischemic stroke), 2 (3 %) – gastrointestinal bleeding of mild severity. All these patients received a prophylactic dose of apixaban due to the presence of 1 thrombosis risk factor: an increase in FVIII activity of more than 150 %.Conclusion. Clinical signs of hemostasis system pathology were observed in 28 % of AL amyloidosis patients, and laboratory signs of hypercoagulability were detected in 92 %. Our developed indications for thrombosis prophylaxis in AL amyloidosis were effective. The issue of FVIII activity increase as the only indication for anticoagulant therapy in AL amyloidosis patients requires further research.
