The Role of Platelets in Venous Thromboembolism.

Multiple factors contribute to the risk of venous thromboembolism (VTE). Platelets have attracted much interest in arterial cardiovascular disease, whereas their role in VTE has received much less attention. Recent evidence suggests that platelets may play a more important role in VTE than previously anticipated. This review discusses the mechanisms that link platelets with venous thrombotic disease and their potential applications as novel risk factors for VTE. In addition, animal studies and randomized clinical trials that highlight the potential effect of antiplatelet therapy in venous thrombosis are evaluated to assess the role of platelets in VTE. The clinical significance of platelets for VTE risk assessment in specific patient cohorts and their role as a suitable therapeutic target for VTE prevention is acknowledged. The role of platelets in VTE is a promising field for future research.

Montoro-García S ，Schindewolf M ，Stanford S ，Larsen OH ，Thiele T ... -  《-》

Why does aspirin decrease the risk of venous thromboembolism? On old and novel antithrombotic effects of acetyl salicylic acid.

It is well established that aspirin, an irreversible inhibitor of platelet cyclooxygenase activity, is effective in secondary prevention of arterial thromboembolic events. The pooled results of the recent randomized, multicenter WARFASA and ASPIRE aspirin trials showed a 32% reduction in the rate of recurrence of venous thromboembolism (VTE) in patients receiving aspirin following VTE. These clinical data support evidence that platelets contribute to the initiation and progression of venous thrombosis and aspirin inhibits thrombin formation and thrombin-mediated coagulant reactions. In addition to the known acetylation of serine 529 residue in platelet cyclooxygenase-1, the postulated mechanisms of aspirin-induced antithrombotic actions also involve the acetylation of other proteins in blood coagulation, including fibrinogen, resulting in more efficient fibrinolysis. This review summarizes current knowledge on the aspirin-induced antithrombotic effects that potentially explain clinical studies showing reduced rates of VTE events in aspirin-treated subjects.

Undas A ，Brummel-Ziedins K ，Mann KG 《-》

Clinical outcome in patients with venous thromboembolism receiving concomitant anticoagulant and antiplatelet therapy.

Patients with arterial disease receiving antiplatelet agents may develop venous thromboembolism (VTE) and need anticoagulant therapy, although concomitant use of these drugs may increase bleeding risk. We analyzed RIETE data and compared clinical outcomes depending on decision to discontinue or maintain antiplatelet therapy at VTE diagnosis. Consecutive patients with acute VTE were enrolled in RIETE. Only patients receiving antiplatelet therapy at baseline were included in this analysis. Primary outcomes were: rate of subsequent ischemic events, major bleeding or death during anticoagulation course. 1178 patients who received antiplatelet drugs at VTE diagnosis were included. Antiplatelet therapy was discontinued in 62% of patients. During anticoagulation course, patients also receiving antiplatelet therapy had higher rates of lower limb amputations (2.28 vs. 0.21 events per 100 patients-years; p<0.01), any ischemic events (5.7 vs. 2.28 events per 100 patients-years; p<0.05) or death (23.6 vs. 13.9 deaths per 100 patients-years; p<0.01). No differences in the rate of major bleeding or recurrent VTE were revealed. In matched analysis, patients on antiplatelet therapy were found to have a significantly higher rate of limb amputations (odds ratio: 15.3; 95% CI: 1.02-229) and an increased number of composite outcomes including all-cause deaths, arterial and VTE events (odds ratio: 1.46; CI: 1.03-2.06), with no differences in major bleeding rate. Concomitant anticoagulant and antiplatelet therapy in patients with VTE and arterial disease is not associated with increased risk for bleeding, recurrent VTE or death. The worse outcome observed in patients who continued antiplatelet therapy requires further investigations.

Tzoran I ，Brenner B ，Sakharov G ，Trujillo-Santos J ，Lorenzo A ，Madridano O ，López-Sáez JB ，Monreal M ，RIETE investigators ... -  《-》

Influence of diagnosis of venous thromboembolism on immature platelets, absolute platelet count and platelet aggregation over time.

Wustrow I ，Ebner C ，Langwieser N ，Haller B ，Luppa PB ，Bradaric C ，Bongiovanni D ，Stundl A ，Laugwitz KL ，Ibrahim T ，Bernlochner I ... -  《-》

Classification of venous thromboembolism (VTE). Platelets in venous thrombosis.

Meijden PE ，Heemskerk JW ，Hamulyák K ，Cate H ... -  《-》