The chequered history of the antiphospholipid syndrome.

Consideration of the chronology of advances in medical knowledge can provide useful insights into the pathogenesis, diagnosis and treatment of diseases. The antiphospholipid syndrome is an enigmatic disorder and this is reinforced by the misleading associated terminology, the adoption of which results directly from early discoveries relating to the condition. Thus the target antigen of the causative autoantibodies in antiphospholipid syndrome does not reside on phospholipid, and the frequently associated lupus anticoagulant is not restricted to subjects with systemic lupus erythematosus and, paradoxically, despite causing prolongation of clotting times in vitro it is associated with a pronounced tendency to thrombosis.

Antiphospholipid syndrome: unusual clinical presentations.

Although the typical thrombotic manifestations of antiphospholipid syndrome, and pregnancy complications, are well recognised, the literature is awash with reports of more obscure associations and apparent complications. Some occur sufficiently frequently to be regarded as occasional features of the syndrome, whereas in other instances there remains doubt about any pathogenic role for antiphospholipid antibodies. The distinction is important as wrong assumptions may lead to failure to seek alternative diagnoses and the implementation of inappropriate treatments.

SPIN (Scottish Pregnancy Intervention) study: a multicenter, randomized controlled trial of low-molecular-weight heparin and low-dose aspirin in women with recurrent miscarriage.

To assess whether treatment with enoxaparin and low-dose aspirin, along with intensive pregnancy surveillance, reduces rate of pregnancy loss compared with intensive pregnancy surveillance alone in women with history of 2 or more consecutive previous pregnancy losses, a parallel group, multicenter, randomized controlled trial was performed in the United Kingdom and New Zealand. Participants (n = 294) presenting for initial antenatal care at fewer than 7 weeks' gestation with history of 2 or more consecutive previous pregnancy losses at 24 or fewer weeks' gestation and no evidence of anatomic, endocrine, chromosomal, or immunologic abnormality were randomly assigned to receive either enoxaparin 40 mg subcutaneously and 75 mg of aspirin orally once daily along with intense pregnancy surveillance or intense pregnancy surveillance alone from random assignment until 36 weeks' gestation. The primary outcome measure was pregnancy loss rate.

Anti-endothelial antibodies interfere in apoptotic cell clearance and promote thrombosis in patients with antiphospholipid syndrome.

Antiphospholipid syndrome is an important cause of recurrent thrombotic events. The pathogenesis of the thrombosis remains unclear, but it has been suggested that anti-phospholipid Abs, which are laboratory markers for the disease and include species capable of binding to vascular endothelial cells, play an important role. We hypothesized that these anti-endothelial Abs promote thrombosis through interference with clearance of dying cells.

Screening and treatment for heritable thrombophilia in pregnancy failure: inconsistencies among UK early pregnancy units.

The significance of heritable thrombophilia in pregnancy failure is controversial. We surveyed all UK Early Pregnancy Units and 70% responded. The majority test routinely for heritable thrombophilias; 80%, 76% and 88% undertook at least one screening test in late miscarriage, recurrent miscarriage and placental abruption, respectively.

Can we predict bleeding?

The prior identification of subjects who are likely to bleed excessively when subjected to operative surgery and other invasive procedures is desirable. Frequently, reliance is placed on laboratory-based screening tests of blood coagulation for this purpose. However, published evidence does not support this approach as the tests are not fit for purpose, and their sensitivity and specificity are low.

The influence of anti-endothelial/antiphospholipid antibodies on fibrin formation and lysis on endothelial cells.

The prothrombotic mechanisms associated with antiphospholipid antibodies remain incompletely defined. Antibody binding to endothelial cells in vitro is a feature of antiphospholipid antibody-positive sera. We hypothesised that impairment of endothelium-dependent fibrinolysis by antiphospholipid/anti-endothelial antibodies is a contributory factor in the pathogenesis of thrombosis.

Antiphospholipid syndrome: an evolving story.

Antiphospholipid Syndrome (APS) is a form of immune mediated thrombophilia, presenting as recurrent thrombotic events and pregnancy morbidity, in association with positive laboratory tests for antiphospholipid antibodies (APA) in the form of Lupus Anticoagulant (LA) or anticardiolipin antibodies(ACA). Insights into the pathophysiology of the condition suggest that some antibodies are prothrombotic in vivo, and that the mechanism of thrombosis is likely to be multifactorial. APS has a broad spectrum of clinical presentations, and the laboratory diagnosis can be difficult due to heterogeneity of APAs and poor standardisation of laboratory tests.

Pharmacogenetics in the management of coumarin anticoagulant therapy: the way forward or an expensive diversion?

Greaves discusses a new study in that takes us closer to being able to adopt a pharmacogenetic approach to reduce bleeding risk from coumarin therapy.

Screening for thrombophilia in high-risk situations: a meta-analysis and cost-effectiveness analysis.

Laboratory testing for the identification of heritable thrombophilia in high-risk patient groups have become common practice; however, indiscriminate testing of all patients is unjustified. The objective of this study was to evaluate the cost-effectiveness of universal and selective history-based thrombophilia screening relative to no screening, from the perspective of the UK National Health Service, in women prior to prescribing combined oral contraceptives and hormone replacement therapy, women during pregnancy and patients prior to major orthopaedic surgery. A decision analysis model was developed, and data from meta-analysis, the literature and two Delphi studies were incorporated in the model.

Oral contraceptives, hormone replacement therapy, thrombophilias and risk of venous thromboembolism: a systematic review. The Thrombosis: Risk and Economic Assessment of Thrombophilia Screening (TREATS) Study.

Combined oral contraceptives, oral hormone replacement therapy and thrombophilias are recognised risk factors for venous thromboembolism in women. The objective of this study was to assess the risk of thromboembolism among women with thrombophilia who are taking oral contraceptives or hormone replacement therapy, conducting a systematic review and metaanalysis. Of 201 studies identified, only nine met the inclusion criteria.

Clopidogrel has no effect on D-dimer and thrombin-antithrombin III levels in patients with peripheral arterial disease undergoing peripheral percutaneous transluminal angioplasty.

Objective: Coagulation activation markers are significantly elevated in patients with peripheral arterial disease compared with healthy controls. The more severe the disease, the higher the markers. Increased coagulation activation may contribute to the disease process and the risk of complications in patients with peripheral arterial disease, particularly after endovascular intervention.

Helicobacter pylori seropositivity is associated with enhanced platelet activation in patients with intermittent claudication.

Objective: Patients with intermittent claudication have a significantly increased risk of mortality from cardiovascular and cerebrovascular causes. Helicobacter pylori infection and abnormal platelet function have been shown to be associated with atherosclerosis as well as with acute ischemic events. The aim of this study was to assess for the first time the relation between H pylori serology status, platelet activation, and endothelial injury in patients with intermittent claudication.

Surface expression of fatty acid translocase (FAT/CD36) on platelets in myeloproliferative disorders and non-insulin dependent diabetes mellitus: effect on arachidonic acid uptake.

Increased platelet reactivity has been implicated in the vascular complications of myeloproliferative diseases and diabetes mellitus. The mechanisms of platelet hyperresponsiveness have not been fully explained. Expression of CD36 or fatty acid translocase (FAT) and its role in arachidonic acid (AA) uptake by platelets were examined in subjects with myeloproliferative disorders (MPD), those with non-insulin-dependent diabetes mellitus (NIDDM), and in normal, healthy, age-matched controls.

Lupus anticoagulant testing: improvements in performance in a UK NEQAS proficiency testing exercise after dissemination of national guidelines on laboratory methods.

Laboratory screening for lupus anticoagulant (LA) has been shown to be suboptimal in several studies. Guidelines have recently been published by an expert group for the British Committee for Standards in Haematology, in an attempt to standardize and improve screening procedures. The value of using screening tests conforming with these guidelines was investigated in a United Kingdom National External Quality Assessment Scheme (UK NEQAS) proficiency testing exercise.