Pulmonary thromboendarterectomy is a curative resolution for chronic thromboembolic pulmonary hypertension associated with antiphospholipid syndrome: a retrospective cohort study

Antiphospholipid antibodies in chronic thromboembolic pulmonary hypertension

Acquired thrombophilia and in particular the presence of antiphospholipid antibodies (aPL) may play an important role in the development of chronic thromboembolic pulmonary hypertension (CTEPH). Young patients suffering from an episode of unprovoked pulmonary embolism (PE), or PE provoked by mild risk factors, should be tested for aPL. In case of a positive result, they should be closely followed up and lifelong anticoagulant treatment should be considered. Indeed, aPL-induced thrombophilia may favor PE recurrence with the consequence of possible CTEPH development. The aPL profiles play an important role in this pathway. Patients with PE and triple positivity (lupus anticoagulant, LAC, anti-cardiolipin, aCL, and anti-β2-glycoprotein I, aβ2GPI) are at the highest risk of recurrence and deserve maximum protection by anticoagulant treatment with warfarin.

Chronic thromboembolic pulmonary hypertension in patients with antiphospholipid syndrome: Risk factors and management

BACKGROUND

Antiphospholipid syndrome (APS) may cause chronic thromboembolic pulmonary hypertension (CTEPH). Current knowledge regarding prevalence and risk factors for CTEPH among APS patients is limited. We sought to determine clinical features and biomarkers that could identify APS subjects suffering from CTEPH, and describe the prevalence, course and treatment outcomes of patients with APS-CTEPH.

METHODS

504 APS patients were treated in our center during 2008 to 2019. We studied clinical and laboratory features of 69 APS patients, comparing 19 patients diagnosed with CTEPH (APS-CTEPH) and treated accordingly, with 50 consecutive age and gender matched patients with no evidence of pulmonary hypertension (APS-No-CTEPH).

RESULTS

CTEPH prevalence was 3.8% in our APS cohort and was linked with the following parameters: primary APS (p < 0.05); prior pulmonary embolism (p < 0.001); recurrent venous thromboembolism (VTE) (p < 0.001); lower platelet counts (p < 0.001); triple anti-phospholipid antibodies positivity (p < 0.001), higher titers of anti-cardiolipin IgG (p < 0.001), anti-B2GPI IgG (p < 0.001), and high Russell viper venom time ratio (RVVT-ratio) (p < 0.05). Additionally, history of catastrophic APS was more prevalent in APS-CTEPH vs APS-No-CTEPH (p < 0.05). Of APS-CTEPH patients, 15/19 underwent pulmonary endarterectomy (PEA): In 12/15 the procedure was elective and resulted in good perioperative and long-term outcomes, while only 1 of 3 patients that underwent urgent PEA survived.

CONCLUSIONS

CTEPH is relatively common in APS. Primary APS, prior PE, recurrent VTE, thrombocytopenia and specific anti-phospholipid antibodies predict CTEPH in APS. Active assessment for CTEPH in APS patients should be considered, as PEA was found to be effective and relatively safe, especially if electively performed.

2020 Chinese Expert-based Consensus on the Diagnosis and Treatment of Connective Tissue Disease Associated Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a severe complication of connective tissue disease (CTD) and is one of the leading causes of morbidity and mortality among patients with this condition. To establish an expert-based consensus on the diagnosis and treatment of CTD-associated PAH, a multidisciplinary consensus development panel was established. The consensus panel is composed of 45 experts in rheumatology, cardiology, pulmonology, and radiology, most of whom are members of the Group of Pulmonary Vascular and Interstitial Lung Diseases (ILD) Associated with Rheumatic Diseases. The consensus development panel compiled 9 recommendations for the diagnosis and treatment of CTD-associated PAH. It covers screening, diagnosis, disease evaluation, risk assessment, the use of immunosuppressive agents, and PAH-specific therapy with a treat-to-target approach. The consensus is intended to facilitate decision-making and standardize the care of CTD-associated PAH in China.

Lysophosphatidic acid promotes thrombus stability by inducing rapid formation of neutrophil extracellular traps: A new mechanism of thrombosis

BACKGROUND

Lysophosphatidic acid (LPA), a bioactive phospholipid released by activated platelets, can induce platelet shape changes and aggregation, which may play an important role in thrombosis. In contrast, the interaction of LPA with neutrophils in thrombosis has not been studied. Recently, neutrophil extracellular traps (NETs) have been shown to bind plasma proteins and activate platelets, which promotes thrombosis.

OBJECTIVES

To investigate whether LPA could activate neutrophils to release NETs, predisposing to thrombosis and promoting thrombus stability.

METHODS

Levels of neutrophils, NETs, and LPA were detected in 56 participants. Immunofluorescence of NETs and autotaxin, the LPA-producing ectoenzyme, were performed. Induction of NETs and signaling pathways were explored in vitro.

RESULTS

Patients with acute pulmonary embolism showed elevated levels of neutrophils, NETs (dsDNA, MPO-DNA, citrullinated histone H3, and nucleosomes), LPA18:1, and LPA20:4. NETs were present in human intrapulmonary thrombi and were surrounded by autotaxin. LPA18:1 induced rapid release of NETs from human neutrophils via a peptidylarginine deiminase 4-dependent pathway. LPA-induced NETs provided a scaffolding for plasma protein binding and generated a tissue plasminogen activator (tPA)-resistant blood clot. Addition of deoxyribonuclease I to tPA significantly accelerated the lysis of clots and human intrapulmonary thrombi. Furthermore, LPA-induced NETs could activate platelets to release LPA.

CONCLUSION

This is the first study to implicate LPA in regulating the stability of thrombi by inducing rapid release of NETs in vitro and ex vivo, which could be a new mechanism of thrombosis. These findings provide new insight into the prevention and therapy of venous thromboembolic disease by targeting the LPA-NET signaling pathway.