Influence of apixaban on commonly used coagulation assays: results from the Belgian national External Quality Assessment Scheme.

INTRODUCTION: The Belgian national External Quality Assessment Scheme performed a survey to assess the effect of the direct oral anticoagulant apixaban on the coagulation assays prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen and antithrombin as performed with a large number of reagent/instrument combinations. METHODS: Four lyophilized plasma samples spiked with apixaban (0, 41, 94 and 225 ng/mL) were sent to the 195 Belgian and Luxembourg clinical laboratories performing coagulation testing. RESULTS: PT and aPTT were barely influenced at the concentrations tested. At 225 ng/mL apixaban, PT and aPTT clotting times were only 1.15 times longer than at 0 ng/mL. Among PT reagents, RecombiPlasTin 2G® showed a slightly higher sensitivity with 225 ng/mL apixaban prolonging the PT clotting time 1.3-fold. Among aPTT reagents, there was no appreciable difference in sensitivity. Fibrinogen results were unaffected by the presence of apixaban, but antithrombin activity was considerably overestimated when measured with a FXa-based assay. At 225 ng/mL apixaban, the median percentage increase in antithrombin level was 31% when measured with the Liquid Antithrombin® reagent and 44% with the Innovance Antithrombin® reagent. CONCLUSION: Our data provide clinical laboratories with useful information on the impact of apixaban on their routine coagulation assays.

Effects of Physical Exercise on Markers of Cellular Immunosenescence: A Systematic Review.

Aging affects negatively the immune system, defined as immunosenescence, which increases the susceptibility of elderly persons to infection, autoimmune disease, and cancer. There are strong indications that physical exercise in elderly persons may prevent the age-related decline in immune response without significant side effects. Consequently, exercise is being considered as a safe mode of intervention to reduce immunosenescence. The aim of this review was to appraise the existing evidence regarding the impact of exercise on surface markers of cellular immunosenescence in either young and old humans or animals. PubMed and Web of Science were systematically screened, and 28 relevant articles in humans or animals were retrieved. Most of the intervention studies demonstrated that an acute bout of exercise induced increases in senescent, naïve, memory CD4+ and CD8+ T-lymphocytes and significantly elevated apoptotic lymphocytes in peripheral blood. As regards long-term effects, exercise induced increased levels of T-lymphocytes expressing CD28+ in both young and elderly subjects. Few studies found an increase in natural killer cell activity following a period of training. We can conclude that exercise has considerable effects on markers of cellular aspects of the immune system. However, very few studies have been conducted so far to investigate the effects of exercise on markers of cellular immunosenescence in elderly persons. Implications for immunosenescence need further investigation.

[Rivaroxaban: Xarelto--recommendations for pharmacists]. / Le Rivaroxaban (Xarelto): guide de la pratique officinale.

Rivaroxaban is one of the new oral anticoagulants (NOACs). It has many potential advantages in comparison with Vitamin K Antagonists (VKA). It has a predictable anticoagulant effect and does not theoretically require biological monitoring. It is also characterized by less food and drug interactions. However, due to major risks associated with over- and under-dosage, its optimal use in patients should be carefully followed by health care professionals. The aim of this article is to provide recommendations for pharmacists on the practical use of Xarelto in its different approved indications. This document is adapted from the practical user guide of rivaroxaban which was developed by an independent group of Belgian experts in the field of thrombosis and haemostasis.

Guidelines for the use of fresh frozen plasma.

Recommendations, which aim at standardising and rationalising clinical indications for the transfusion of fresh frozen plasma (FFP) in Belgium, were drawn up by a working group of the Superior Health Council. For this purpose the Superior Health Council organised an expert meeting devoted to "Transfusion Guidelines: Pathogen reduction, products and indications for the transfusion of plasma" in collaboration with the Belgian Haematological Society.The experts discussed the indications for the transfusion of FFP, pathogen reduction for FFP and the practical issues of administering FFP and plasma-derived concentrates. The recommendations formulated by the experts were validated by the working group with the purpose of harmonising FFP transfusion in Belgian hospitals.

External quality assessment in the measurement of haemoglobin by blood gas analysers in Belgium.

OBJECTIVE: The Belgian national External Quality Assessment Scheme (EQAS) for haematology organized a survey to assess the reliability of haemoglobin (Hb) measurements with the blood gas analysers (BGAs) currently available in Belgian hospitals. MATERIAL AND METHODS: All hospital laboratories received two specimens of fresh EDTA anticoagulated whole blood and were asked to determine the Hb concentration using both the conventional haematology analyser (HA) and all BGAs in the hospital. Ninety-seven hospital laboratories participated in the study and a total of 166 results were reported. The BGAs used (grouped according to technology) were Rapidlab 845, 855, 865 (Bayer 1, n = 41), Rapidlab 1245, 1265, Rapidpoint 405 (Bayer 2, n = 19), GEM Premier 3000 (Instrumentation Laboratory, IL, n = 13), ABL 500 and 600 series (Radiometer 1, n = 13), ABL 700 and 800 series (Radiometer 2, n = 35), Omni C, S5 (Roche 1, n = 7), Omni 3, 6, 9, S2, S4, S6 (Roche 2, n = 21). RESULTS: For the BGAs from Bayer, Radiometer and Roche, interlaboratory variation ranged from 0.6 % to 4.1 %, indicating good precision and close agreement between centres. A significant negative bias observed on the GEM Premier 3000 using the EDTA anticoagulated blood samples did not appear to be present in fresh heparinized whole blood samples. There was no significant difference in imprecision and bias between Hb measurements on BGA situated in and outside the central laboratory.

Factor V inhibitor after injection of human thrombin (tissucol) into a bleeding peptic ulcer.

Endoscopic injection of fibrin glue into a bleeding peptic ulcer is an effective and safe treatment modality. The present report describes a patient who developed rectal bleeding from an arteriovenous malformation after endoscopic injection of fibrin glue containing human thrombin into a gastric ulcer. Additional laboratory investigations revealed the presence of an inhibitor against coagulation factor V, which resulted in severe coagulopathy, triggering the bleeding. Acquired factor V inhibitors have frequently been reported with the use of bovine thrombin, but to our knowledge, they have never been documented in patients exposed to human thrombin. Endoscopists should be aware of this rare, but potentially serious, complication.

Plasma D-dimer concentrations in different clinical conditions.

D-dimers (DD), specific degradation products of crosslinked fibrin, are markers for activation of plasma coagulation and/or fibrinolysis. DD results below the cut-off level are proven to be useful to rule out the probable diagnosis of deep venous thrombosis (DVT) and/or pulmonary embolism (PE). Our objective was to demonstrate that positive DD occur in many diseases and certain physiological conditions as high age and pregnancy and to look for gradations in positivity between different pathological conditions. We wanted to investigate the request attitude of our clinicians concerning DD. Positive DD results still confuse some physicians. Retrospectively, we examined medical records of 574 consecutive patients, in whom plasma DD were measured in daily routine. Both outpatients (n = 423) and inpatients (n = 151) were included. We noted their clinically predominant disease. Measurement of DD concentration is too often requested by clinicians, in any medical condition, and is not always clinically relevant. The relation of a positive result and the clinical problem is sometimes not understood. Overall, we found 64% DD positivity with a median concentration of 775 micrograms/L. We found elevated DD concentrations in various clinical conditions.

Growth factor receptor profile of CD34+ cells in AML and B-lineage ALL and in their normal bone marrow counterparts.

Leukaemic cells show a low clonogenic activity and a heterogeneous proliferative response to growth factors. We investigated whether this could be due to an altered expression of growth factor receptors on the leukaemic precursors. Receptors for G-CSF, stem cell factor (SCF), IL-3, IL-6 and IL-7 were detected on CD34+ cells in AML and B-lineage ALL with monoclonal antibodies and flow cytometry. The expression was compared with that on myeloid and B-lymphoid CD34+ cells in normal bone marrow. Leukaemic CD34+ cells expressed the same receptors as their normal counterparts. AML and B-lineage ALL could be distinguished by the growth factor receptor profile of their CD34+ cells. SCFR, G-CSFR and IL-6Ralpha were found in AML, IL-7R in B-lineage ALL and IL-3Ralpha in both. IL-3Ralpha was upregulated in AML and B-lineage ALL CD34+ cells, while samples with low or high expression were present for the other receptors. This variable expression could correlate with the heterogeneous response of leukaemic cells to growth factors. Functional studies on isolated CD34+ cells are needed to investigate this further.

Different expression of adhesion molecules on CD34+ cells in AML and B-lineage ALL and their normal bone marrow counterparts.

The expression of adhesion molecules on CD34+ cells in acute myeloid leukemia (AML) and B-lineage acute lymphoblastic leukemia (B-lineage ALL) was compared with that on the myeloid and B-lymphoid CD34+ cells in normal bone marrow. Bone marrow aspirates of 10 patients with AML, 8 patients with B-lineage ALL and of 6 healthy volunteers were examined. The phenotype of the CD34+ cells was determined with a double immunofluorescence method and flow cytometry. CD34+ cells in AML and B-lineage ALL showed a lower expression of VLA-2 and VLA-3 and a higher expression of ICAM-1 and LFA-3 than their normal bone marrow counterparts. AML CD34+ cells had less L-selectin but more VLA-5 on their surface membrane than normal myeloid CD34+ cells. B-lineage ALL CD34+ cells showed an overexpression of LFA-3. In individual patients deficiencies or over-expression of the beta1 integrin chain, VLA-4, PECAM-1 or HCAM also occurred. An abnormal adhesive capacity of the leukemic cells may influence their proliferation, their localisation and apoptosis. An aberrant expression of adhesion molecules may be used for the detection of minimal residual leukemia in these patients.

[Antithrombin deficiency and thrombosis in a young child]. / Déficit en antithrombine et thromboses chez le jeune enfant.

BACKGROUND: Thromboses represent a rare event in children and may be due to a deficiency of antithrombin. CASE REPORT: A 10-year-old boy developed thrombosis due to a congenital quantitative deficiency in antithrombin, confirmed by molecular biology. His father was diagnosed with the same deficiency. The child was first treated with heparin and is now on antivitamin K. He is well 26 months after diagnosis. CONCLUSION: When a young patient presents with a thrombotic event, a congenital deficiency in one of the inhibitors of coagulation, one of which is antithrombin, should be looked for and the condition treated as soon as possible.

Use of tranexamic acid for an effective blood conservation strategy after total knee arthroplasty.

We have investigated the effect of treatment with tranexamic acid, an inhibitor of fibrinolysis, on blood loss, blood transfusion requirements and blood coagulation in a randomized, double-blind, placebo-controlled study of 42 patients after total knee arthroplasty. Tranexamic acid 15 mg kg-1 (n = 21) or an equivalent volume of normal saline (n = 21) was given 30 min before surgery and subsequently every 8 h for 3 days. Coagulation and fibrinolysis values, blood loss and blood units administered were measured before administration of tranexamic acid, 8 h after the end of surgery and at 24 and 72 h after operation. Coagulation profile was examined (bleeding time, platelet count, prothrombin time (PT), activated partial thromboplastin time (aPTT), plasminogen, beta-thromboglobulin and fibrinogen). Fibrinolysis was evaluated by measurement of concentrations of D-dimer and fibrinogen degradation products (FDP). Total blood loss in the tranexamic acid group was 678 (SD 352) ml compared with 1419 (607) ml in the control group (P < 0.001), and occurred primarily during the first 24 h after surgery. Thirteen patients received 1-5 u. of packed red blood cells in the control group compared with two patients in the tranexamic acid group, who received 3 u. (P < 0.001). Postoperative packed cell volume values were higher in the tranexamic acid group despite fewer blood transfusions. Postoperative concentrations of plasminogen were decreased significantly in the tranexamic acid group (P < 0.001). Platelet count, PT, aPTT, bleeding time, beta-thromboglobulin, fibrinogen and FDP concentrations did not differ between groups, but D-dimer concentrations were increased in the control group. Thromboembolic complications occurred in two patients in the control group compared with none in the tranexamic acid group.

The molecular basis of antithrombin deficiency in Belgian and Dutch families.

The molecular basis of hereditary antithrombin (AT) deficiency has been investigated in ten Belgian and three Dutch unrelated kindreds. Eleven of these families had a quantitative or type I AT deficiency, with a history of major venous thromboembolic events in different affected members. In the other two families a qualitative or type II AT deficiency was occasionally diagnosed. DNA studies of the AT gene were performed, using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) analysis, followed by direct sequencing of the seven exons and intron-exon junction regions. Six novel point mutations were identified: four missense, one nonsense mutation and a single nucleotide deletion near the reactive site, causing a frameshift with premature translation termination. In two kindreds the underlying genetic defect was caused by a whole gene deletion, known as a rare cause of AT deficiency. In these cases, Southern blot and polymorphism analysis of different parts of the AT gene proved useful for diagnosis. In another kindred a partial gene deletion spanning 698 basepairs could precisely be determined to a part of intron 3B and exon 4. In two type I and in both type II AT deficient families a previously reported mutation was identified. In all cases, the affected individuals were heterozygous for the genetic defect.

Desmin (a low molecular weight dermatan sulphate) versus heparin in the treatment of patients with deep venous thrombosis.

OBJECTIVE: There is theoretical and experimental evidence which indicates that Desmin, a low molecular weight dermatan sulphate, could be an attractive alternative to heparin in the treatment of deep venous thrombosis (DVT). The present study compares both compounds in patients with established DVT. METHODS: Seventeen consecutive patients admitted with DVT were included in a randomised open study comparing continuous intravenous administration of Desmin and continuous intravenous administration of heparin. Clinical, laboratory and imaging parameters were used to assess the efficacy and safety of both treatments. RESULTS: The results of the coagulation tests confirmed the published data on the antithrombotic profile of Desmin. A trend towards better biochemical tolerance was observed with Desmin. Repeated echo duplex examinations of the deep venous system could not document further thrombus extension in any patient. Pre- and post-treatment phlebographic Marder scores showed a non-significant trend towards superior efficacy of Desmin. Overall, the results regarding efficacy and safety were not significantly different in the two groups. CONCLUSION: Desmin can be safely studied as an alternative to conventional anticoagulation in the treatment of DVT.

Anaesthetic management of a parturient with severe congenital factor XI deficiency undergoing caesarean section for triplet pregnancy.

The report describes the anaesthetic management of a Jewish patient of Ashkenazi descent with severe factor XI deficiency complicated by thrombocytopenia for caesarean section for triplets at the 35th week of gestation. Perioperative management consisted of sustained replacement therapy with fresh frozen plasma and platelets until the sixth postoperative day. General anaesthesia was used for the procedure. No other maternal or neonatal complications occurred.

Pearson marrow pancreas syndrome: a molecular study and clinical management.

Human mitochondrial DNA (mt DNA) lesions can cause a heterogeneous group of mitochondrial degenerative disorders. We report on a 5-year-old patient suffering from the full-blown picture of Pearson syndrome. His symptoms started in the first year of life with failure to thrive, followed by chronic diarrhoea and lactic acidosis at 18 months of age. Analysis of mitochondrial DNA revealed large amounts of mt DNA molecules with a 2.7 kb deletion in all tissues examined. The diagnosis of Pearson syndrome was made initially in the absence of haematological disturbances. In the following months neutropenia, sideroblastic anaemia and hypoparathyroidism developed. Daily administration of dichloroacetate (DCA) and bicarbonate controls the lactic acidosis, while episodic treatments with filgastrim (Neupogen) reverse episodes of severe neutropenia. Calcium and vitamin D supplementation compensate for the hypoparathyroidism. Chronic administration of DCA and supportive treatment for a long period help to stabilize patients with multiorgan dysfunction.

Comparative study of antiphospholipid antibody detection in eleven Belgian laboratories.

Twenty-six plasma samples have been sent to 11 different Belgian laboratories in order to detect the presence of antiphospholipid antibodies, either by immunological methods and/or by coagulation tests. A good concordance between laboratories was observed for coagulation tests. Laboratories using detection tests and performing mixing procedures and neutralisation procedures displayed the highest sensitivity as compared with laboratories which did not perform one of these two latter procedures. The concordance between laboratories for the immunological methods was much worse as compared with coagulation tests. This may be attributable either to an intrinsic problem of the immunological tests or to a selection bias due the fact that the plasmas used in this study were selected in coagulation laboratories only where the chance to find a lupus anticoagulant positive/ELISA antiphospholipid negative sample is high.