International consensus statement on preliminary classification criteria for definite antiphospholipid syndrome: report of an international workshop

NLRP3-Induced NETosis: A Potential Therapeutic Target for Ischemic Thrombotic Diseases?

Ischemic thrombotic disease, characterized by the formation of obstructive blood clots within arteries or veins, is a condition associated with life-threatening events, such as stroke, myocardial infarction, deep vein thrombosis, and pulmonary embolism. The conventional therapeutic strategy relies on treatments with anticoagulants that unfortunately pose an inherent risk of bleeding complications. These anticoagulants primarily target clotting factors, often overlooking upstream events, including the release of neutrophil extracellular traps (NETs). Neutrophils are integral components of the innate immune system, traditionally known for their role in combating pathogens through NET formation. Emerging evidence has now revealed that NETs contribute to a prothrombotic milieu by promoting platelet activation, increasing thrombin generation, and providing a scaffold for clot formation. Additionally, NET components enhance clot stability and resistance to fibrinolysis. Clinical and preclinical studies have underscored the mechanistic involvement of NETs in the pathogenesis of thrombotic complications, since the clots obtained from patients and experimental models consistently exhibit the presence of NETs. Given these insights, the inhibition of NETs or NET formation is emerging as a promising therapeutic approach for ischemic thrombotic diseases. Recent investigations also implicate a role for the nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome as a mediator of NETosis and thrombosis, suggesting that NLRP3 inhibition may also hold potential for mitigating thrombotic events. Therefore, future preclinical and clinical studies aimed at identifying and validating NLRP3 inhibition as a novel therapeutic intervention for thrombotic disorders are imperative.

Antithrombotic therapy in antiphospholipid syndrome with arterial thrombosis: a systematic review and network meta-analysis

Introduction

The optimal secondary thromboprophylactic strategies for patients with antiphospholipid syndrome (APS) and arterial thrombosis remain controversial. This study aimed to evaluate the comparative efficacy and safety of various antithrombotic strategies in APS with arterial thrombosis.

Methods

A comprehensive literature search was conducted using OVID MEDLINE, EMBASE, Web of Science, and the Cochrane Controlled Register of Trials (CENTRAL) from inception until 30 September 2022, with no language restrictions. The inclusion criteria for eligible studies were as follows: inclusion of APS patients with arterial thrombosis, treatment with either antiplatelet agents, warfarin, direct oral anticoagulants (DOACs), or a combination of these therapies, and reporting of recurrent thrombotic events.

Results

We conducted a frequentist random-effects network meta-analysis (NMA) involving 13 studies with a total of 719 participants, comprising six randomized and seven non-randomized studies. In comparison to single antiplatelet therapy (SAPT), the combined use of antiplatelet and warfarin demonstrated a significant reduction in the risk of recurrent overall thrombosis, with a risk ratio (RR) of 0.41 (95% CI 0.20 to 0.85). Dual antiplatelet therapy (DAPT) showed a lower risk of recurrent arterial thrombosis compared to SAPT although the difference did not reach statistical significance, with an RR of 0.29 (95% CI 0.08 to 1.07). DOAC was associated with a significant increase in the risk of recurrent arterial thrombosis, with an RR of 4.06 (95% CI 1.33 to 12.40) when compared to SAPT. There was no significant difference in major bleeding among various antithrombotic strategies.

Discussion

Based on this NMA, the combination of warfarin and antiplatelet therapy appears to be an effective approach in preventing recurrent overall thrombosis in APS patients with a history of arterial thrombosis. While DAPT may also show promise in preventing recurrent arterial thrombosis, further studies are needed to confirm its efficacy. Conversely, the use of DOACs was found to significantly increase the risk of recurrent arterial thrombosis.

Proliferative Vasculopathy Associated With Antiphospholipid Antibodies in Patients With Neurological Symptoms

Background

Proliferative vasculopathy (PV) associated antiphospholipid syndrome (APS) in the central nervous system is a rare un(der)recognized form of extra-criteria manifestations of APS. This study investigated the angiographic characteristics of cerebral and cervical arteries in patients with PV associated with antiphospholipid antibodies (aPLs).

Methods

Patients with aPLs, neurologic symptoms and diffuse luminal narrowing on brain or neck magnetic resonance angiography were selected from electronic medical records. Vascular wall and intraluminal pathology were examined by high-resolution vessel wall MR imaging (VW-MRI).

Results

A total of 11 patients (six men and five women) with PV-aPL, of median (interquartile range) age 42 (34–61) years, were included. Median anticardiolipin antibodies IgG titer was 78.9 (28.2–134.0) units and anti-beta 2 glycoprotein I antibodies (aB2GPIs) IgG titer was 227.2 (0.0–1012.1) units. All patients had diffuse luminal narrowing in the carotid basilar and/or cerebral arteries, five in the internal carotid artery (ICA); two each in the middle cerebral artery (MCA) and vertebral artery; and one each in the basilar artery (BA) and posterior cerebral artery. On VW-MRI, four patients showed concentric thickening of the vascular walls of the ICA and/or MCA and two showed mild eccentric wall thickening of the ICA or BA. All patients received antithrombotic treatment. In two patients with extremely high aB2GPIs titer, diffuse narrowing progressed despite treatment with antithrombotic agents on follow-up imaging.

Conclusions

This study suggests that PV-aPL might be a distinct extra-criteria manifestation of APS that can manifest as long-segmental diffuse stenosis of cerebral and cervical arteries. It should be considered in relatively young patients with neurologic symptoms and aPLs.

Antiphospholipid syndrome and its role in pediatric cerebrovascular diseases: A literature review

Antiphospholipid syndrome (APS) or Hughes syndrome is an acquired thromboinflammatory disorder. Clinical criteria of APS diagnosis are large- and small-vessel thrombosis as well as obstetric problems; laboratory criteria are the presence of antiphospholipid antibodies (lupus anticoagulant, anticardiolipin antibodies and anti-β2-glycoprotein-1). The presence of at least 1 clinical and 1 laboratory criterion allows definitive diagnosis of APS. Primary APS is diagnosed in patients without features of connective tissue disease; secondary APS is diagnosed in patients with clinical signs of autoimmune disease. A high frequency of catastrophic APS as well as a high tendency to evolve from primary APS to secondary syndrome during the course of lupus and lupus-like disease is a feature of pediatric APS. The most characteristic clinical presentation of APS in the pediatric population is venous thrombosis, mainly in the lower limbs, and arterial thrombosis causing ischemic brain stroke. Currently, no diagnostic criteria for pediatric APS exist, which probably results in an underestimation of the problem. Similarly, no therapeutic procedures for APS specific for children have yet been established. In the present literature review, we discussed data concerning APS in children and its role in cerebrovascular diseases, including pediatric arterial ischemic stroke, migraine and cerebral venous thrombosis.

Segmental small bowel necrosis associated with antiphospholipid syndrome: A case report

Antiphospholipid syndrome is a multi-system disease characterized by the formation of thromboembolic complications and/or pregnancy morbidity, and with persistently increased titers of antiphospholipid antibodies. We report the case of a 50-year-old, previously healthy man who presented with fever and new-onset, dull abdominal pain. A contrast-enhanced computed tomography scan showed segmental small bowel obstruction, for which an emergency laparotomy was performed. Histopathologic examination of resected tissues revealed multiple intestinal and mesenteric thromboses of small vessels. Laboratory tests for serum antiphospholipid (anticardiolipin IgM) and anti-β2-glycoprotein I antibodies were positive. Despite proactive implementation of anticoagulation, steroid, and antibiotic therapies, the patient’s condition rapidly deteriorated, and he died 22 d after admission. This case highlights that antiphospholipid syndrome should be suspected in patients with unexplainable ischemic bowel and intestinal necrosis presenting with insidious clinical features that may be secondary to the disease, as early diagnosis is critical to implement timely treatments in order to ameliorate the disease course.

Review on Effectiveness of Primary Prophylaxis in aPLs with and without Risk Factors for Thrombosis: Efficacy and Safety

Context. Antiphospholipid antibodies syndrome is an autoimmune disorder that is characterized by the association between presence of antiphospholipid antibodies and risk of thrombosis and/or pregnancy morbidity. Objectives. To systematically review the evidence for primary prophylaxis in patients with antiphospholipids antibodies syndrome or APS with or without other traditional risk factors of thrombosis when they did not have any thrombotic event yet. Methods. PubMed, the Cochrane Library, and Allied Health Literature were searched for studies that examined the efficacy and safety of primary prophylaxis in aPL patients from 1990 to February 2013. We examined literature looking at patients with aPLs with other risk factors for thrombosis and aPLs with no additional risk factors for thrombosis. Conclusion. We concluded that, in patients with aPLs, primary prophylaxes with HCQ and aspirin have been observed to reduce the frequency of thrombotic events in the case of asymptomatic aPL-positive patients with SLE. We also in this study concluded that LDA was effective in patients with autoimmune diseases. Independent cardiovascular risk factors include autoimmune defects such as SLE, rheumatoid arthritis, and atherosclerosis, where overall venous thrombosis will be induced by systemic inflammation. This review concludes that HCQ is an effective primary approach when compared to aspirin.