Antiphospholipid antibody profile-based outcome of purely vascular and purely obstetric antiphospholipid syndrome

Obstetric antiphospholipid syndrome carries an increased lifetime risk for obstetric and thrombotic complications-a population-based study

Background

Antiphospholipid syndrome (APS) can present with either a thromboembolic event (thrombotic APS, TAPS) or an obstetric complication (obstetric APS, OAPS). Data on long-term complications in the different APS phenotypes are limited.

Objectives

We aimed to compare obstetric history, antiphospholipid antibody profiles, obstetric and thromboembolic complications, and pregnancy outcomes between TAPS and OAPS.

Methods

This retrospective cohort study included women who delivered singleton pregnancies between 1998 and 2020. One hundred sixteen thousand four hundred nine women were included, resulting in 320,455 deliveries. Among the included patients, 71 were diagnosed with APS, 49 were classified as OAPS, and 22 as TAPS. The demographics, obstetric, neonatal, and thrombotic outcomes were compared among TAPS, OAPS, and the general obstetric population.

Results

OAPS patients had an increased risk of thrombotic events compared with the general obstetric population (odds ratio [OR] 18.0; 95% CI, 8.7-37.2). In pregnancies following the diagnosis of APS, despite standard antithrombotic treatment, OAPS patients exhibited an elevated risk of placenta-related and neonatal complications compared with the general obstetric population (late fetal loss [adjusted OR {aOR}, 15.3; 95% CI, 0.5-27.5], stillbirth [aOR, 5.9; 95% CI, 2.2-15.4], placental abruption [aOR, 4.8; 95% CI, 1.5-15.3], preeclampsia [aOR, 4.4; 95% CI, 2.5-7.7], fetal growth restriction [aOR, 4.3; 95% CI, 8.5-27.5], small for gestational age neonate [aOR, 4.0; 95% CI, 2.4-6.6], and low Apgar scores [Apgar'1: aOR, 2.6; 95% CI, 1.3-10.4; Apgar'5: aOR, 3.7; 95% CI, 1.3-10.4]). TAPS patients exhibited increased risk of preeclampsia (aOR, 3.1; 95% CI, 1.2-8).

Conclusion

OAPS patients exhibit a heightened risk of thrombotic events compared with the general obstetric population. Despite treatment, OAPS and TAPS still presented obstetric complications. These findings, after confirmation in prospective studies, need to be taken into consideration when planning the treatment approach for these patients.

Effects of anti-beta 2-glycoprotein 1 antibodies and its association with pregnancy-related morbidity in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by venous, arterial, or small-vessel thrombosis and/or pregnancy-related morbidity, associated with persistent positivity of antiphospholipid antibodies (aPL). Pregnancy-related morbidity in APS patients is characterized by unexplained fetal deaths, premature birth of morphologically normal newborns, and/or consecutive pregnancy losses before the 10^th week of gestation. Beta 2-glycoprotein 1 (ß2GP1) is the main antigen recognized by aPL and plays an essential role in the pathogenesis of APS. Antibodies against ß2GP1 (aß2GP1) are involved in damage-generating mechanisms in APS due to their interaction with trophoblasts, decidua, and endothelial cells. aß2GP1 might be used as a prognostic tool for obstetric risk stratification and ß2GP1 could be a target for molecular-targeted treatment to prevent pregnancy morbidity in APS. This review describes these aspects of aß2GP1, including effects on different cellular targets, its association with the severity of obstetric manifestations and the potential of ß2GP1-targeted therapies for APS.

The first thrombotic event in purely obstetric antiphospholipid syndrome patients and in antiphospholipid antibody carriers: comparison of incidence and characteristics

PURPOSE

The long-term risk of thrombosis after pregnancy in women with purely obstetric antiphospholipid syndrome (OAPS) is not well defined. The current study's primary outcome was to evaluate the incidence and characteristics of the first thrombotic event in OAPS, identifying the risk factors for thrombosis in OAPS was its secondary one.

METHODS

Patients with purely OAPS were consecutively enrolled between September 1999 and September 2019. Subjects without a history of pregnancy morbidity or thrombosis but with persistent positivity for one or more antiphospholipid antibodies (aPL carriers) made up the control group. The study groups included 94 OAPS patients and 124 aPL carriers who were matched for clinical and laboratory parameters.

RESULTS

An event rate of 0.49/100 patient years was registered in OAPS patients during a mean follow-up of 8.7 years ± 5.5 SD. Kaplan-Meier survival analysis revealed that the cumulative incidence of thromboembolic events was not significantly different in OAPS patients vs aPL carriers. Arterial thrombosis and cerebrovascular events were the more frequent types of vascular involvement in the two groups. As far as risk factors for thrombosis were concerned, the presence of lupus anticoagulant significantly prevailed in both thrombotic OAPS patients and thrombotic aPL carriers with respect to purely OAPS patients and aPL carriers who did not develop thrombosis (p = 0.01 and p = 0.00, respectively).

CONCLUSION

Just as for aPL carriers, closer monitoring and possibly, a pharmacological prophylaxis should be reserved for OAPS patients at highest risk of developing the first thrombotic event.

Obstetric outcomes in patients with primary thrombotic and obstetric antiphospholipid syndrome and its relation to the antiphospholipid antibody profile

Introduction: Previous studies suggested different obstetric outcomes between patients with thrombotic or obstetric antiphospholipid syndrome, but the data are inconclusive. Aims: To investigate obstetric outcomes and their relation to the antiphospholipid antibody profile in primary thrombotic or obstetric antiphospholipid syndrome patients and compare those to a control population. Materials and methods: A retrospective single-centre study on a cohort of 30 pregnant women with primary antiphospholipid syndrome treated at Karolinska University Hospital Solna, Sweden between 2000 and 2016. The pregnancy outcomes were compared to the outcomes of all pregnancies in Stockholm County during the same period. Results: Preeclampsia ( p < 0.001), low birth weight at delivery ( p = 0.001), Apgar < 7 at 5 minutes ( p < 0.001) and small infants ( p < 0.001) were more common in antiphospholipid syndrome patients compared to controls. Obstetric antiphospholipid syndrome patients had a higher incidence of small infants ( p = 0.023), lower birth weight ( p = 0.013) and infants born with complications ( p=0.004) compared to thrombotic antiphospholipid syndrome. Mothers with triple antibody positivity had a higher incidence of preeclampsia ( p = 0.03), preterm delivery ( p = 0.011), small infants ( p=0.002) and infants born with complications ( p = 0.012). Conclusions: Patients with primary antiphospholipid syndrome, especially those with obstetric antiphospholipid syndrome and triple antibody positivity, are at higher risk for adverse pregnancy outcomes, even under antithrombotic treatment. More frequent antenatal controls in high-risk patients can further improve outcomes.