French National Diagnostic and Care Protocol for antiphospholipid syndrome in adults and children.

Antiphospholipid syndrome (APS) is a chronic autoimmune disease involving vascular thrombosis and/or obstetric morbidity and persistent antibodies to phospholipids or certain phospholipid-associated proteins. It is a rare condition in adults and even rarer in children. The diagnosis of APS can be facilitated by the use of classification criteria based on a combination of clinical and biological features. APS may be rapidly progressive with multiple, often synchronous thromboses, resulting in life-threatening multiple organ failure. This form is known as "catastrophic antiphospholipid syndrome" (CAPS). It may be primary or associated with systemic lupus erythematosus (associated APS) and in very rare cases with other systemic autoimmune diseases. General practitioners and paediatricians may encounter APS in patients with one or more vascular thromboses. Because APS is so rare and difficult to diagnosis (risk of overdiagnosis) any suspected case should be confirmed rapidly and sometimes urgently by an APS specialist. First-line treatment of thrombotic events in APS includes heparin followed by long-term anticoagulation with a VKA, usually warfarin. Except in the specific case of stroke, anticoagulants should be started as early as possible. Any temporary discontinuation of anticoagulants is associated with a high risk of thrombosis in APS. A reference/competence centre specialised in autoimmune diseases must be urgently consulted for the therapeutic management of CAPS.

Association between D-Dimer levels and mortality in patients with coronavirus disease 2019 (COVID-19): a systematic review and pooled analysis.

BACKGROUND: Several observational studies have reported elevated baseline D-dimer levels in patients hospitalized for moderate to severe coronavirus disease 2019 (COVID-19). These elevated baseline D-dimer levels have been associated with disease severity and mortality in retrospective cohorts. OBJECTIVES: To review current available data on the association between D-Dimer levels and mortality in patients admitted to hospital for COVID-19. METHODS: We performed a systematic review of published studies using MEDLINE and EMBASE through 13 April 2020. Two authors independently screened all records and extracted the outcomes. A random effects model was used to estimate the standardized mean difference (SMD) with 95% confidence intervals (CI). RESULTS: Six original studies enrolling 1355 hospitalized patients with moderate to critical COVID-19 (391 in the non-survivor group and 964 in the survivor group) were considered for the final pooled analysis. When pooling together the results of these studies, D-Dimer levels were found to be higher in non-survivors than in-survivors. The SMD in D-Dimer levels between non-survivors and survivors was 3.59µg/L (95% CI 2.79-4.40µg/L), and the Z-score for overall effect was 8.74 (P<0.00001), with a high heterogeneity across studies (I2=95%). CONCLUSIONS: Despite high heterogeneity across included studies, the present pooled analysis indicates that D-Dimer levels are significantly associated with the risk of mortality in COVID-19 patients. Early integration of D-Dimer testing, which is a rapid, inexpensive, and easily accessible biological test, can be useful to better risk stratification and management of COVID-19 patients.

High prevalence of antibodies to platelet factor 4 heparin in patients with antiphospholipid antibodies in absence of heparin-induced thrombocytopenia.

Seventy-two patients with antiphospholipid antibodies (aPL), with or without antiphospholipid syndrome (APS), were studied for detection of heparin-PF4-induced antibodies (HPIA) using a commercial kit (Asserachrom HPIA) PF4-dependant enzyme-linked immunoassay (ELISA) test. None of the patients had a medical history of heparin induced thrombocytopenia (HIT). Eleven percent of patients were positive for HPIA. Plasma from 40 of the 72 patients (seven positive and 33 negative), was also tested with the other available HPIA ELISA (GTI) kit. Five patients were positive with both ELISA kits, two were highly positive only with Asserachrom HPIA and four only with GTI. None of the positive patients had severe thrombocytopenia. Two patients have never received heparin treatment. No relationship was found between HPIA presence and patients' age, sex, aPL levels or presence of lupus anticoagulant. No significant difference in HPIA presence was observed in patients with primary APS, secondary APS or aPL without APS. We found a poor correlation between the two commercial ELISA showing that, on the same blood sample, a patient could be highly positive with one technique and negative with the other. The PF4-dependant enzyme-linked immunoassay, which is often the first test used for the diagnosis of HIT, should be interpreted cautiously in patients with aPL since there is a danger of overdiagnosis and overtreatment.

Analysis of biological phenotypes from 42 patients with inherited factor VII deficiency: can biological tests predict the bleeding risk?

BACKGROUND AND OBJECTIVES: Inherited factor VII (FVII) deficiency is a rare bleeding disorder characterized by a poor relationship between reported FVII clotting activity (FVII:C) and bleeding tendency. Our study was aimed at defining biological parameters that are possibly predictive for bleeding risk in this condition. DESIGN AND METHODS: Forty-two FVII-deficient patients (FVII:C <30%) were classified into two opposite clinical groups defined as severe and non-or-mild bleeders. For each patient, plasma samples were collected and then investigated for FVII:C (using a sensitive method and human recombinant thromboplastin as the reagent), FVII antigen, activated FVII coagulant activity (FVIIa:C) and the free-form of tissue factor pathway inhibitor. RESULTS: None of these tests could be used as highly accurate predictors of bleeding. Nevertheless, both FVII:C and FVIIa:C differed significantly between the two clinical groups. Using ROC-curve analysis, two critical values of 8% and 3mIU/mL for FVII:C and FVIIa:C, respectively, could be proposed to discriminate between severe bleeders and non-or-mild bleeders. INTERPRETATION AND CONCLUSIONS: A highly accurate diagnostic test for predicting bleeding tendency in inherited FVII deficiency still eludes definition, highlighting the fact that factors other than FVII itself interfere with the expression of bleeding phenotypes in this condition. Nevertheless, potential critical values using sensitive FVII:C and FVIIa:C methods may be useful in clinical laboratories for FVII-deficient patients. Those patients with FVII:C levels higher than 8% FVII:C or FVIIa:C higher than 3 mIU/mL, with no other hemostatic defect, seem to have a minimal risk of severe bleeding. Extended clinical studies are needed to support these findings.