Factor XI (FXI) deficiency is a rare congenital hemostatic disorder associated with increased bleeding tendency in trauma, surgery or when other hemostatic defects are present. Perioperative ...hemostatic management of a patient with a severe FXI deficiency undergoing major oncological liver and colorectal surgery with therapeutic plasma exchange (TPE) with fresh frozen plasma (FFP) is reported.
A 54-year-old male with severe FXI deficiency was scheduled for resection of synchronous rectal cancer and multiple liver metastases. Baseline prothrombin time
(PT) was 97 %, activated partial thromboplastin time (aPTT) 89 s(s) and FXI levels <1 IU/dL. The rotational thromboelastometry (ROTEM™) presented a prolonged INTEM clotting time (CT) = 443 s (RV 100−240 s) and a clot formation time (CFT) = 110 s (RV 30–100 s). TPE with FFP was carried out achieving FXI levels up to 46 IU/dL and an aPTT of 33 s, normalizing thromboelastometry parameters to an INTEM CT = 152 s and a CFT = 86 s before the procedure. After surgery, the patient received daily FFP to maintain FXI levels above 30 IU/dL until discharge on the eighth day. A total of 30 FFP units were transfused during hospital stay. No significant bleeding events neither transfusion related complications were observed during the perioperative period.
Given the lack of correlation between FXI levels and bleeding risk, a multidisciplinary approach based on daily FXI levels monitoring, close clinical assessment and factor supplementation is mandatory. In conclusion, TPE with FFP is an efficacious alternative strategy to correct severe FXI deficiency in patients undergoing major surgery.
Summary
Introduction
Oral direct thrombin and Xa inhibitors are worldwide distributed for prevention and treatment of thrombosis. It is important to recognize their effects on lupus anticoagulant ...(LA) testing. The aim of the study is to describe the rate of false‐positive results of LA tests on plasmas of patients with previous negative LA tests results that receive dabigatran etexilate (DAB) 110 mg/twice a day, rivaroxaban (RIV) 10 mg/day or 15 mg/twice a day, or enoxaparin 40 mg/day.
Methods
Blood was taken between 1.5 and 4 h post administration. Tests evaluated are as follows: prothrombin time, APTT, dilute Russell viper venom time (DRVVT) screen, APTT, and DRVVT mixing studies, index of circulating anticoagulant (ICA) with normal plasma, screen/confirm normalized ratio (NR) for DRVVT and silica clotting time (SCT).
Results
Plasmas from patients taking DAB (n = 22) presented 100% prolonged APTT and DRVVT with ICA above the cutoff point and 81.8% positive screen/confirm NR, 100% prolonged SCT screen, but 4.5% positive confirmatory NR. All patients receiving RIV at 15 mg/twice a day (n = 4) presented positive DRVVT screen, mixing, and confirmatory tests, 75% and 100% prolonged APTT and SCT screen, with negative screen/confirm NR. Those taking RIV 10 mg/day (n = 22) showed 81.8% prolonged DRVVT screen, 82.3% and 76.5% of them with positive mixing and confirmatory studies. Patients receiving enoxaparin also presented high prevalence of APTT and DRVVT false‐positive results.
Conclusion
Dabigatran etexilate, RIV, and enoxaparin affect tests for LA not only in screening and mixing, but also in confirmatory studies. We considered that LA testing should not to be performed when patients are taken these drugs, particularly if blood is collected at peak, in order to avoid false‐positive results.
Laboratory determination of fibrinogen/fibrin degradation product (FDP) levels is important as a hyperfibrinolytic state marker. The aim of the study was to verify the analytical performance of an ...automated immunoturbidimetric assay (AIMT) for FDP and its comparison to a latex agglutination semiquantitative (SLAT) test.
Total precision and accuracy was calculated following the EP 15-A2 protocol at two levels of controls. The protocol EP6 was performed for linearity. For semi-quantitative methods comparison, 71 consecutive samples were used. Concordance between methods results in term of positive and negative, and in categories, from <10 to > 160 µg/mL, was calculated through Cohen kappa coefficient ().
Total CV%: low control (10.8 µg/mL) 8.0 and 3.7 vs. 4.8 and high control (31.3 µg/mL) 2.7 and 3.8 vs. 3.6, for coagulometer ACL TOP 500 and 300 vs. manufacturer claimed, respectively. Linearity between 0 and 125 µg/mL showed polynomial fit analysis applicable. When correlating AIMT to SLAT, a good concordance was observed: of results expressed as positive-negative = 79.5% with 90.1% of agreement (p < 0.001), of results expressed as categories = 72.2% (p < 0.001) with 80.3% concordance.
AIMT presented good analytical performance, and the concordance with SLAT by comparison of patients' samples results was also good. The implementation of IMMT in the clinical laboratory is suitable and reliable.
Homozygous or double heterozygous factor XIII (FXIII) deficiency is characterized by soft tissue hematomas, intracranial and delayed spontaneous bleeding. Alterations of thromboelastography (TEG) ...parameters in these patients have been reported. The aim of the study was to show results of TEG, TEG Lysis (Lys 60) induced by subthreshold concentrations of streptokinase (SK), and to compare them to the clot solubility studies results in samples of a 1-year-old girl with homozygous or double heterozygous FXIII deficiency.
A year one girl with a history of bleeding from the umbilical cord. During her first year of life, several hematomas appeared in soft upper limb tissue after punctures for vaccination and a gluteal hematoma. One additional sample of a heterozygous patient and three samples of acquired FXIII deficiency were also evaluated.
Clotting tests, von Willebrand factor (vWF) antigen and activity, plasma FXIII-A subunit (pFXIII-A) were measured by an immunoturbidimetric assay in a photo-optical coagulometer. Solubility tests were performed with Ca(2+)-5 M urea and thrombin-2% acetic acid. Basal and post-FXIII concentrate infusion samples were studied. TEG was performed with CaCl2 or CaCl2 + SK (3.2 U/mL) in a Thromboelastograph.
Prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time, fibrinogen, factor VIIIc, vWF, and platelet aggregation were normal. Antigenic pFXIII-A subunit was < 2%. TEG, evaluated at diagnosis and post FXIII concentrate infusion (pFXIII-A= 37%), presented a normal reaction time (R), 8 min, prolonged k (14 and 11min respectively), a low Maximum-Amplitude (MA) ( 39 and 52 mm respectively), and Clot Lysis (Lys60) slightly increased (23 and 30% respectively). In the sample at diagnosis, clot solubility was abnormal, 50 and 45 min with Ca-Urea and thrombin-acetic acid, respectively, but normal (>16 hours) 1-day post-FXIII infusion. Analysis of FXIII deficient and normal plasma mixtures (< 2-102% of pFXIII-A), showed that Ca-urea solubility was abnormal at pFXIII-A < 9%, thrombin-acetic acid at pFXIII-A<18%, but TEG MA and elasticity at 23% and Lys60 with SK at pFXIII-A< 40%.
TEG parameters MA and elasticity, and Lys 60 in TEG either with Ca(2+) or Ca(2+) and SK are more sensitive to low levels of pFXIII than solubility tests. The increased Lys60 induced by a subthreshold concentration of SK could probably reflect the clot characteristics "in vivo" in many patients with pFXIII levels between 5-40% and could be potentially considered as screening test.
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