New approaches to prevention of thrombosis in the antiphospholipid syndrome: hopes, trials, and tribulations

Fish oil attenuates neurologic severity of antiphospholipid syndrome in a mice experimental model

INTRODUCTION

Murine experimental models of antiphospholipid syndrome (eAPLS) showed neurologic dysfunction and therapeutic effect of the anticoagulant enoxaparin is well established. Omega-3 fatty acids and curcumin, tested in neuroinflammation and auto-immunity diseases, might be interesting therapeutic candidates. The aim of this study was to evaluate the effects of these candidates on neurologic severity in eAPLS.

METHODS

One month after immunization of BALB/c mice with beta-2-glycoprotein I, daily treatments were initiated with enoxaparin (1 mg/kg), omega-3 fatty acids (0.5 g/kg), and curcumin (200 mg/kg) for 3 months.

RESULTS

Mortality was significantly decreased by enoxaparin and omega-3 treatments. Fish oil and curcumin group exhibited the highest mean of swimming behavior in forced swim test in surviving mice. Mice under omega-3 fatty acids or curcumin presented low anxiety-like behavior in the elevated plus-maze test. Cerebral histopathology revealed heavy inflammatory infiltrates in cortical and subcortical regions with vacuolization, swelling, and degeneration of astrocytes in the control group, with aggravation under curcumin; no infiltrate was retrieved in enoxaparin and omega-3 groups.

CONCLUSION

Our study is the first to demonstrate a potential therapeutic effect of omega-3 fatty acids in eAPLS. Enoxaparin and omega-3 fatty acids combination would be interesting for further investigation.

Cognitive dysfunction and white matter abnormalities in antiphospholipid syndrome

Diagnosis of the antiphospholipid syndrome (APS) requires that a patient have both a clinical event (thrombosis or pregnancy loss) and persistently positive antiphospholipid antibodies (aPL). Although stroke and transient ischemic attack are the most common neurologic manifestations of APS, both cognitive dysfunction and magnetic resonance imaging (MRI) white matter hyperintensities can occur in aPL-positive patients (with or without APS). Relatively little is known about the cognitive pattern in aPL-positive patients; MRI white matter hyperintensities may be related to underlying attentional and executive cognitive impairment. Studies with sophisticated neuroimaging techniques aimed to better understand MRI white matter hyperintensities may eventually facilitate our understanding of cognitive dysfunction in aPL-positive patients.

Cardiovascular events in patients with antiphospholipid antibodies: strategies of prevention

Antiphospholipid antibodies are a heterogeneous group of auto-antibodies against phospholipids-binding proteins. The antiphospholipid syndrome is an autoimmune disorder characterized by the clinical association of antiphospholipid antibodies with a condition of hypercoagulability that can affect any blood vessel. Involvement of larger vessels, such as arteries or veins, manifests in the form of thrombosis or thromboembolism, whereas involvement of small vessels manifests as thrombotic micro-angiopathy. The antiphospholipid syndrome is also characterized by the presence of recurrent fetal loss. Patients who are persistently positive for antiphospholipid tests, and who have an arterial thrombosis or venous thrombosis history, are at increased risk of recurrence. Oral anticoagulant therapy is the mainstay of treatment for the thrombotic manifestations of the syndrome. Therapy with anticoagulant drugs should be long-term. On the other hand, although the thromboembolic potential of antiphospholipid antibodies has been well documented, there is still no general consensus on the prophylactic treatment of antiphospholipid antibodies carriers who have never developed vascular/obstetric manifestations. The effect of primary prophylaxis in antiphospholipid antibodies positive individuals is not well known and no evidence-based recommendations exist for thrombosis prevention in these individuals. However, the presence of risk factors for thrombosis increases the risk of first event of antiphospholipid antibodies positive patients. In conclusion, there is still much to learn on primary prophylaxis of asymptomatic antiphospholipid antibodies carriers. Hopefully, evidence-based guidelines will be available in the future.

D-dimer level and the risk for thrombosis in systemic lupus erythematosus

BACKGROUND AND OBJECTIVES

Patients who have systemic lupus erythematosus (SLE) and manifest antiphospholipid antibodies (APA) are at increased risk for thrombosis; however, it is difficult to predict who will clot. This study tested the hypothesis that peak D-dimer level measured routinely during follow-up identifies whether a hypercoagulable state is developing and, therefore, the patient is at increased risk for thrombosis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

One hundred consecutive patients who had SLE with recurrent activity (71% renal SLE) and were evaluated for or enrolled in the Ohio SLE Study were studied. D-dimer testing was done annually and usually at SLE flare or other serious illness. When D-dimer was elevated, evaluation for thrombosis (large vessel, small vessel, or Libman-Sacks) was undertaken. Mean follow-up was 37.5 +/- 15 SD months.

RESULTS

Of those with peak D-dimer <0.5 microg/ml (n = 46), 0% thrombosed, 33% had APA. Of those with peak D-dimer 0.5 to 2.0 microg/ml (n = 19), 6% thrombosed, 44% had APA. Of those with peak D-dimer >2.0 microg/ml (n = 36), 42% thrombosed, 76% had APA. The most common causes of elevated D-dimer in the absence of demonstrable thrombosis were SLE flare and systemic infection. D-dimer levels were usually elevated for several months before thrombosis.

CONCLUSIONS

Patients with SLE and normal D-dimer levels are at low risk for thrombosis, irrespective of APA status. Those with persistent unexplained elevated D-dimer levels, particularly when >2.0 microg/ml, are at high risk for thrombosis.

Controversies in the antiphospholipid syndrome: can we ever stop warfarin?

Patients with antiphospholipid syndrome are at increased risk for recurrent arterial and venous thrombosis and therefore benefit from long term warfarin therapy. The optimal duration of warfarin therapy after a first venous thromboembolic event is however a matter of some controversy and many questions remain unanswered. After reviewing and analysing the available evidence, we discuss some common scenarios in everyday clinical practice where treatment decisions are difficult.

Neurological manifestations of the antiphospholipid syndrome: risk assessments and evidence-based medicine

The antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterised by autoantibody production and vascular thrombosis or pregnancy morbidity. Autoantibodies generated against phospholipid and phospholipid-binding proteins often impair phospholipid-dependent clotting assays (lupus anticoagulants). These autoantibodies activate endothelial cells, platelets and biochemical cascades and can exist in autoimmune disorders such as lupus. Consistently positive antibodies may worsen the severity of thrombo-occlusive disease. The most common neurological manifestations of APS include stroke and transient ischaemic attacks due to arterial thromboses. Antiphospholipid antibodies may cause additional neurological impairments through both vascular and immune mechanisms. Antiaggregant or anticoagulant therapies are indicated for APS-related ischaemic strokes. Treatment regimens for asymptomatic antibody-positive patients and those with refractory disease remain controversial. There is scant literature on neurological APS manifestations in paediatric patients. Assessment of traditional cardiovascular and inherited thrombophilia risk factors is essential in patients with APS. Modifiable risk factors and valvular heart disease may worsen thrombotic and cerebrovascular outcomes. Alternative therapies such as statins, anti-malarials, angiotensin-converting enzyme inhibitors and thrombin inhibitors warrant further research.

Antiphospholipid antibody effects on monocytes

Although the presence of autoantibodies is known to increase the risk of thrombosis in the antiphospholipid syndrome, the mechanism by which these antibodies exert their effects is poorly understood. Several studies suggest that autoantibody-mediated dysregulation of monocytes is one pathobiologic mechanism of this disease. Recent studies have focused on extra- and intracellular interactions involved in monocyte activation and expression of procoagulant activity. Agents specifically targeting monocyte activation and activity may provide a novel and efficacious approach that is safer than current antithrombotics.

The antiphospholipid syndrome

The antiphospholipid syndrome (APS) is an autoimmune disorder characterized by the clinical association of antiphospholipid autoantibodies (aPL) with a syndrome of hypercoagulability that can affect any blood vessel, irrespective of type or size. Involvement of larger vessels, such as arteries or veins, manifests in the form of thrombosis or embolism, whereas involvement of smaller vessels, including capillaries, arterioles, and venules, manifests as thrombotic microangiopathy. Virtually any organ in the body, including the kidney, can be affected. Here, we review the basic principles and recent advances in our understanding of APS, and discuss the broad spectrum of renal diseases that have been observed in association with this syndrome. We also discuss the impact that APS may have on pre-existing renal disease as well as current recommendations for treatment of APS.

Deep Hypothermic Circulatory Arrest and Bivalirudin Use in a Patient With Heparin-Induced Thrombocytopenia and Antiphospholipid Syndrome

BACKGROUND

Patients with heparin-induced thrombocytopenia II (HIT II) need an alternative nonheparin-based method of anticoagulation for cardiopulmonary bypass (CPB) to prevent thrombosis and thrombosis related complications.

METHODS

Bivalirudin was used during CPB and deep hypothermic circulatory arrest (DHCA) for resection of multiple right atrial masses in a patient with HIT II and antiphospholipid antibodies syndrome (APS). Anticoagulation was monitored with the activated clotting time (ACT) and a target ACT of 450 seconds or greater was maintained.

RESULTS

Surgical removal of multiple right atrial masses was successful and there was no evidence of thromboembolic events. Clot was noticed in the cardiotomy and venous reservoir after CPB was discontinued and the system flushed. The postoperative course was uneventful.

CONCLUSIONS

Anticoagulation was successfully managed with bivalirudin, a new short-acting, and direct thrombin inhibitor. Further studies are necessary to evaluate the safety of bivalirudin during DHCA.

Anticoagulation Strategies for Treatment of Ischemic Stroke and Antiphospholipid Syndrome: Case Report and Review of the Literature

A 49-year-old Caucasian man with antiphospholipid syndrome who experienced an ischemic stroke required multidisciplinary decisions regarding acute and long-term care. The patient first received warfarin and unfractionated heparin, followed by low-molecular-weight heparin. However, he developed complications from these drugs (warfarin-induced necrosis and heparin-induced thrombocytopenia), resulting in thigh necrosis and multiple additional cerebral and peripheral infarcts. His condition improved after warfarin and the heparins were discontinued, and a direct thrombin inhibitor, argatroban, was given intravenously for acute treatment. Argatroban is the only anticoagulant known to be safe in patients who experience an acute ischemic stroke in the setting of heparin-induced thrombocytopenia. For long-term anticoagulation, fondaparinux, an indirect, selective factor Xa inhibitor, was given subcutaneously. The patient received intravenous dexamethasone, later changed to azathioprine, for immunomodulatory treatment. He had significant improvement in his neurologic deficits without recurrent events over the next 18 months. Management of anticoagulation therapy in patients with antiphospholipid syndrome is complex and challenging, and therapeutic strategies need to be evaluated further.

New Treatments for Antiphospholipid Syndrome

Challenges in new drug development for APS include the controversy about the strength of association between aPL and thrombotic events, and unknown mechanism of aPL-induced thrombosis. In the long-term management of patients who have APS, controlled studies with warfarin alternatives (such as antiplatelet agents), the new anticoagulant agents (such as direct and indirect thrombin inhibitors), and newer therapeutic agents are vital. It is highly possible that the current "antithrombotic" approach to patients who are aPL-positive will be replaced by a "more specifically targeted, anti-inflammatory or immunomodulatory" approach in the future.

Antiphospholipid Syndrome: Review

Antiphospholipid syndrome spans many medical disciplines. Classic criteria include the presence of anticardiolipin antibody or lupus anticoagulant with typical complications of thrombosis or pregnancy loss. Other common associated manifestations include livedo reticularis, thrombocytopenia, valvular heart disease, and nephropathy with renal insufficiency, hypertension, and proteinuria. Treatment of serious complications with anticoagulation is standard; generally warfarin for thrombosis and aspirin/heparin for pregnancy prophylaxis. Detailed recommendations regarding precise intensity and duration of anticoagulation are still a subject of debate.

Stroke and antiphospholipid syndrome: the treatment debate

Antiphospholipid syndrome (APS) is one of the most frequent acquired thrombophilias. Thromboses can be at both the venous and arterial level, are usually recurrent and frequently affect cerebral circulation. Although it is difficult to predict which patients with antiphospholipid antibodies (aPL) will develop thrombosis, once a thrombotic event has taken place, secondary prevention is mandatory. Recommendations for treatment of APS have long been based on studies with a retrospective design. Recently, three prospective studies (two controlled and one uncontrolled small series) have addressed the role of antiaggregant and anticoagulant therapy in patients with stroke and aPL. However, results from prospective and retrospective studies are not in full agreement. In addition to the obvious differences in design, other factors such as the important variability in the study groups account for the discrepancy. While future investigation must better define homogeneous subsets of patients with APS, current secondary prophylaxis of thrombosis in these patients must be tailored according to individual estimated risk of recurrences, risk of haemorrhage and severity of potential recurrent events. Due to the often devastating consequences of stroke, we believe there is a place for prolonged, high-intensity anticoagulation in patients with APS and cerebral arterial thrombosis.

Stem cell transplantation for autoimmune disorders. Coincidental autoimmune disease in patients transplanted for conventional indications

The practice of stem cell transplantation for severe autoimmune diseases refractory to conventional therapy originated from two landmark discoveries: the excellent results of animal experiments, and serendipitous observations in human coincidental diseases. The latter include patients with an often long-standing autoimmune disease who have developed a haematological condition (aplasia, leukaemia, lymphoma) requiring stem cell transplantation (from marrow as well as from blood). Allogeneic and autologous transplants have been performed. The initial information deriving from both procedures is their feasibility, even more convincing since the patients were affected by two simultaneous severe diseases. The information derived from autologous transplants has, however, now been superseded by the considerable and increasing number of those transplants performed for primary autoimmune diseases. On the other hand, allogeneic stem cell transplantation for very severe autoimmune diseases is being cautiously explored in current protocols. Allogeneic transplants in coincidental disease have also suggested a graft-versus-autoimmunity effect, which may become relevant in conjunction with non-myeloablative, less toxic condition regimens.

What is antiphospholipid syndrome?

The description of antiphospholipid syndrome (APS) is vascular thrombosis and/or pregnancy morbidity occurring in persons with antiphospholipid antibodies (aPL). However, because of an unclear etiopathogenesis and the heterogeneous nature of aPL and of aPL-related clinical manifestations, a single, unambiguous definition of APS does not exist. In this paper, we describe a structured approach to APS, discuss the controversies, and offer descriptions of APS that include: an autoimmune systemic disease with a spectrum of (mostly thrombotic) clinical manifestations, an overdiagnosed disease when aPL is present but has no proven direct causative role in the clinical manifestations, and a disease of controversies that requires clarification of etiology and mechanisms and risk-stratified controlled clinical studies.

Current debates in antiphospholipid syndrome: the acquired antibody-mediated thrombophilia

Antiphospholipid (APL) syndrome is the most common form of acquired thrombophilia. It can cause significant morbidity and even mortality. The term "APL antibodies" represents a heterogeneous group of antibodies associated with this disorder. Currently no single assay can identify every APL antibody. Clinically relevant APL antibodies are mainly anticardiolipin antibodies (ACA) detected by solid phase enzyme-linked immunosorbent assay (ELISA) and lupus anticoagulants (LA) demonstrated by in vitro coagulation assay. However, there are some other antibodies associated with the APL syndrome (i.e., subgroup APL antibodies). ACAs, LAs, and subgroup APL antibodies represent intersecting, but non-identical, subsets of autoantibodies. Thus, those autoantibodies may coexist or may occur independently. Any organ system and any size of vessel can be affected during the clinical course of the disease. Therefore, the APL syndrome can manifest itself in a wide variety of clinical thrombotic features. Fetal loss and pregnancy morbidity represent a specific challenge. Despite tremendous advances in the understanding of the pathogenesis of APL syndrome during the past decade, the mainstay of management is still anticoagulation. However, there is no general agreement regarding the duration and intensity of anti-coagulant therapy. In this review, we focused on the current dilemmas and their present clarifications in the wide clinicopathologic spectrum of APL syndrome and APL antibody-related distinct pathologic conditions.

Treatment of the antiphospholipid antibody syndrome

Numerous questions exist regarding the proper management of patients with the antiphospholipid antibody syndrome (APS). Several recent, randomized-controlled trials have been conducted that attempt to answer the fundamental questions of whom to treat, how to treat, and for how long treatment should last. These studies suggest that APS should be categorized by disease manifestations, and these presentations may have different treatment algorithms. A better understanding of the immune mechanisms that govern thrombosis in this syndrome has led to a wide array of innovative treatment approaches that will require meticulous study.

How much warfarin is enough in APS related thrombosis?

Warfarin is the best available, most effective treatment for the secondary prevention of recurrent thrombosis in antiphospholipid syndrome (APS) patients. However, warfarin is cumbersome for both patients and physicians because of risk for bleeding and the need for frequent monitoring. Much detail regarding optimal management of APS patients still lacks an evidence-based approach. Asymptomatic patients should not receive warfarin. An optimal treatment for patients with livedo, cardiac valve disease, leg ulcers or microangiopathic nephropathy is unknown; it is likely that warfarin is ineffective for these manifestations of the APS. In low risk patients who have not previously failed warfarin, moderate intensity anticoagulation (target international normalized ratio [INR] 2.5) is as effective as, and safer than, high intensity anticoagulation (INR 3.5), at least for patients with venous thrombosis. Current recommendations, based on the opinion rather than on documentation, state that warfarin should be prescribed for the APS patient's life; studies that challenge this conclusion for carefully defined low risk patients whose thromboses occurred with trigger events will be welcome, as will be studies examining alternatives to warfarin, including antiplatelet drugs.