Impaired Fibrinolysis in the Antiphospholipid Syndrome

The pathogenesis of the antiphospholipid syndrome (APS) is complex and involves the persistent presence of antiphospholipid antibodies (aPL) in the bloodstream causing a prothrombotic condition. aPL induce excessive activation of the endothelium, monocytes, and platelets in consort with aberrations in hemostasis/clotting, fibrinolytic system, and complement activation. Impaired fibrinolysis has been found in APS patients with thrombotic as well as obstetric manifestations. Increased levels of plasminogen activator inhibitor-1 and thrombin-activatable fibrinolysis inhibitor, together with the presence of aPL against annexin-2, tissue-type plasminogen activator, and plasminogen contribute to the compromised fibrinolytic activity in these patients. Furthermore, unfavorably altered fibrin morphology, less amenable to fibrinolysis, has been proposed as a novel prothrombotic mechanism in APS. This review aims to summarize the present knowledge of the mechanisms involved in impaired fibrinolysis in APS patients. We also present a case from clinical practice as an illustration of fibrinolysis impairment in APS patients from a real-life setting.

Thromboembolism risk following recurrent miscarriage

Normal pregnancy is associated with extensive changes in hemostasis such that the procoagulant effect becomes dominant. The evolutionary advantage of this hypercoagulability may be to counteract the inherent instability associated with hemochorial placentation, which is unique to human beings. However, overall, there is a four- to 10-fold increased thrombotic risk throughout gestation and the postpartum period. Certain inherited or acquired thrombophilic factors may predispose to arterial and/or venous thrombosis and have a possible association with pregnancy complications, including recurrent miscarriage (RM), which affects up to 5% of couples with childbearing desire. A subgroup of women with RM has been demonstrated to be in a prothombotic state before and after pregnancy. The long-term health implications of this hypercoagulability may imply an increased risk of ischemic heart disease. Moreover, the presence of antiphospholipid antibodies rather than thrombophilic genetic defects (i.e., factor V Leiden or prothrombin G202010A mutation) in patients with RM is a determinant of thrombotic events later in life, especially among those patients having also cardiovascular risk factors. This article highlights the thromboembolic risk in nonpregnant RM patients in different thrombophilic settings and the need for thromboprophylaxis among these patients.