POS0794\u2005INCIDENCE AND PHENOTYPE OF ANTIPHOSPHOLIPID SYNDROME (APS) AFTER PREECLAMPSIA

Abstract

Obstetric Antiphospholipid syndrom (oAPS) is induced by antiphospholipid antibodies (aPL) and associated with specific pregnancy complications. oAPS requires the combination of at least one obstetrical and one laboratory criteria (in 2 or more occasions at least 12 weeks apart). Multiple aPL positivity, lupus anticoagulant (LA) or persistently high aPL titers is defined as high risk aPL profile. “Non-criteria” oAPS are cases not fulfilling the clinical criteria.To investigate the incidence of aPL after preeclampsia and the association of phenotypes of oAPS and pregnancy outcome.The present retrospective cohort analysis included women followed up after preeclampsia. Anti-PL (LA, aCL, anti-β2GBI of IgG and IgM isotype) are assessed 8 to 12 weeks after PE and if positive, again at least 12 weeks apart. According to the ISSHP PE is classified as severe if the blood pressure exceeds 160/110mmHg, or is associated with HELLP syndrome, or eclampsia. FGR is defined as estimated fetal weight <5th, and birth weight <10th percentile, and/or pathologic fetal Doppler.Complete clinical and laboratory data were available for 99 women over a period of 6 years. 38.4% delivered <34\u2009+\u20090 weeks. PE was severe in 63.6% of cases, and the incidence of FGR was 58.9%. HELLP syndrome was diagnosed in 34.3% and in 4 cases it was isolated. The prevalence of aPL was 35 (35.4%) at first evaluation, and 23 (23.2%) were still positive 12 weeks apart. 14/99 (14.1%) cases fulfilled the definition of classical oAPS, and 9/99 (9.1%) delivered >34 weeks (“non-criteria oAPS”). Of interest, the incidende og high risk aPL profiles was similar in both groups (64.3% vs. 77.8%; p=NS). The incidence of HELLP syndrome was higher in the presence of APS (APS: 9/23 [39.1%] vs. 21/76 [27.6%]; p=NS). 3 out of 4 cases with isolated HELLP syndrome were associated with high risk aPL profiles. Overall, aCL IgG was the dominant aPL. 32/35 (91.4%) and 22/23 (95.7%) had positive aCL at first and second investigation, respectively (p=NS). An aCL IgG titer >32.8CU at first assessment yield a LR of 10 for persistent aCL with a sensitivity and specificity of 91.3% and 90.9%, respectively.Classical and “non-criteria” obstetrical APS show a similar aPL pattern and distribution of aPL phenotypes regardless of gestational age at delivery. aCL IgG is the dominant aPL antibody and is highly predictive for aPL persistence at follow up. HELLP syndrome may be an additional feature of oAPS, in particular the isolated form. However, more studies are necessary to explore this possible association.[1]Tektonidou MG et al, EULAR recommendations for the management of antiphospholipid syndrome in adults Ann Rheum Dis. 2019 Oct;78(10):1296-1304. doi: 10.1136/annrheumdis-2019-215213. Epub 2019 May 15.None declared