Antithrombotic triple therapy and coagulation activation at the site of thrombus formation: a randomized trial in healthy subjects.

BACKGROUND: Patients with acute coronary syndrome and concomitant atrial fibrillation may require antithrombotic triple therapy but clinical evidence of safety and efficacy is poor. We have therefore studied the combination of different antithrombotic medicines for coagulation activation in an in vivo model in the skin microvasculature. METHODS AND RESULTS: Platelet activation (ß-thromboglobulin [ß-TG]) and thrombin generation (prothrombin fragment 1 + 2 [F1+2 ], thrombin-antithrombin complex [TAT]) were studied in an open-label, randomized, parallel group trial in 60 healthy male subjects (n = 20 per group) who received ticagrelor and acetylsalicylic acid (ASA) in combination with dabigatran (150 mg bid), rivaroxaban (20 mg od) or phenprocoumon (INR 2.0-3.0). Coagulation biomarkers in shed blood were assessed at 3 h after monotherapy with the medicines under study, at 3 h after triple therapy dosing and at steady state trough conditions. Single doses of ticagrelor, dabigatran or rivaroxaban caused comparable decreases in shed blood ß-TG and were more pronounced than phenprocoumon at an INR of 2.0-3.0. In contrast, thrombin generation was more affected by rivaroxaban and phenprocoumon than by dabigatran. During triple therapy a similarly sustained inhibition of platelet activation and thrombin generation with a maximum decrease of ß-TG, F1+2 and TAT at 3 h post-dosing was noted, which remained below pre-dose levels at trough steady state. CONCLUSION: A triple therapy at steady state with ticagrelor plus ASA in combination with dabigatran or rivaroxaban is as effective as a combination with phenprocoumon for platelet activation and thrombin generation in vivo.

Hyperhomocysteinemia is a risk factor of recurrent venous thromboembolism.

Hyperhomocysteinemia is a risk factor of venous thromboembolism. The risk of recurrence in patients with hyperhomocysteinemia is unknown, and the optimal therapy for these patients after acute venous thromboembolism is uncertain. In a multicenter study, 264 patients with an objectively documented single episode of idiopathic venous thromboembolism were prospectively followed after discontinuation of oral anticoagulants. Patients were classified as hyperhomocysteinemic if their homocysteine levels exceeded the 95th percentile of the controls. The outcome events studied were objectively confirmed deep-vein thrombosis and/or pulmonary embolism. Homocysteine levels were elevated in 66 patients (25%) and normal in 198 patients (75%). Recurrent venous thromboembolism occurred in 12 of 66 patients with hyperhomocysteinemia (18.2%) and in 16 of 198 patients without hyperhomocysteinemia (8.1%). The cumulative probability of recurrence 24 months after discontinuation of oral anticoagulants was 19.2 percent (95 percent confidence interval 8.7-27) in patients with hyperhomocysteinemia and was 6.3 percent (95 percent confidence interval 2.4-10.1; p = 0.001) in those without hyperhomocysteinemia. The relative risk of recurrent thrombosis was higher in patients with hyperhomocysteinemia [RR 2.7 (1.3-5.8), p = 0.009]. Patients with hyperhomocysteinemia are at high risk of recurrent venous thromboembolism. The high prevalence of hyperhomocysteinemia in thrombosis patients together with the increased risk of recurrence warrants extended patient screening. The impact on the risk of recurrence of prolonged anticoagulation, supplementation of folate and vitamin B12, or both have to be investigated.

[Home treatment in hemophilia]. / Die Heimtherapie der Hämophilie.

88 patients with severe haemophilia (66 with haemophilia A without inhibitor, 12 with haemophilia A and inhibitor, 10 with haemophilia B) currently receive comprehensive care at the Vienna haemophilia centre. Data available at the centre and a questionnaire answered by the hemophiliacs were used in order to evaluate the current situation of home care. At present, 62 (70%) out of 88 patients receive home treatment (51 with haemophilia A without inhibitor, 5 patients with haemophilia A and inhibitor and 6 with haemophilia B). For treatment of joint and muscle bleeding mean dosages of 15.3 units/kg body weight of factor VIII concentrate, 17.0 units/kg of factor IX concentrate and 30 units/kg of FEIBA were administered by the hemophiliacs. Children and young patients required higher doses (30 and 17.4 units/kg F VIII, respectively). Two thirds of the bleeding episodes were successfully treated by a single infusion. No severe side effects were observed during home treatment. Home treatment has been widely accepted by the patients. It is regarded as a practical and safe therapy and has improved the life quality of haemophiliac patients.