A 27-year-old patient with a history of severe obstetrical complications and arterial thrombosis received a diagnosis of hereditary thrombotic thrombocytopenic purpura (TTP) due to severe ADAMTS13 ...deficiency when she presented with an acute episode in the 30th week of her second pregnancy. When the acute episode of hereditary TTP became plasma-refractory and fetal death was imminent, weekly injections of recombinant ADAMTS13 at a dose of 40 U per kilogram of body weight were initiated. The patient's platelet count normalized, and the growth of the fetus stabilized. At 37 weeks 1 day of gestation, a small-for-gestational-age boy was delivered by cesarean section. At the time of this report, the patient and her son were well, and she continued to receive injections of recombinant ADAMTS13 every 2 weeks. (Funded by the Swiss National Science Foundation.).
Factor XIII (F XIII) is an essential parameter for final clot stability. The purpose of this study was to determine the impact of the addition of factor (F)XIII on clot stability as assessed by ...Rotation Thromboelastometry (ROTEM). In 90 intensive care patients ROTEM measurements were performed after in vitro addition of F XIII 0.32 IU, 0.63 IU, 1.25 IU and compared to diluent controls (DC; aqua injectabile) resulting in approximate F XIII concentrations of 150, 300 and 600%. Baseline measurements without any additions were also performed. The following ROTEM parameters were measured in FIBTEM and EXTEM tests: clotting time (CT), clot formation time (CFT), maximum clot firmness (MCF), maximum lysis (ML), maximum clot elasticity (MCE) and alpha-angle (alphaA). Additionally, laboratory values for FXIII, fibrinogen (FBG), platelets and haematocrit were contemporaneously determined. In the perioperative patient population mean FBG concentration was elevated at 5.2 g/l and mean FXIII concentration was low at 62%. The addition of FXIII led to a FBG concentration-dependent increase in MCF both in FIBTEM and EXTEM. Mean increases in MCF (FXIII vs. DC) of approximately 7 mm and 6 mm were observed in FIBTEM and EXTEM, respectively. F XIII addition also led to decreased CFT, increased alphaA, and reduced ML in FIBTEM and EXTEM. In vitro supplementation of FXIII to supraphysiologic levels increases maximum clot firmness, accelerates clot formation and increases clot stability in EXTEM and FIBTEM as assayed by ROTEM in perioperative patients with high fibrinogen and low FXIII levels.
Angiostrongylus vasorum
is a cardiopulmonary nematode of canids and is, among others, associated with bleeding disorders in dogs. The pathogenesis of such coagulopathies remains unclear. A deep ...proteomic characterization of sex specific
A. vasorum
excretory/secretory proteins (ESP) and of cuticular surface proteins was performed, and the effect of ESP on host coagulation and fibrinolysis was evaluated
in vitro
. Proteins were quantified by liquid chromatography coupled to mass spectrometry and functionally characterized through gene ontology and pathway enrichment analysis. In total, 1069 ESP (944 from female and 959 from male specimens) and 1195 surface proteins (705 and 1135, respectively) were identified. Among these were putative modulators of host coagulation, e.g., von Willebrand factor type D domain protein orthologues as well as several proteases, including serine type proteases, protease inhibitors and proteasome subunits. The effect of ESP on dog coagulation and fibrinolysis was evaluated on canine endothelial cells and by rotational thromboelastometry (ROTEM). After stimulation with ESP, tissue factor and serpin E1 transcript expression increased. ROTEM revealed minimal interaction of ESP with dog blood and ESP did not influence the onset of fibrinolysis, leading to the conclusion that
Angiostrongylus vasorum
ESP and surface proteins are not solely responsible for bleeding in dogs and that the interaction with the host’s vascular hemostasis is limited. It is likely that coagulopathies in
A. vasorum
infected dogs are the result of a multifactorial response of the host to this parasitic infection.
Background: Thromboelastometry is a whole blood assay performed to evaluate the viscoelastic properties during blood clot formation and lysis. Rotation thromboelastography (ROTEM®, Pentapharm GmbH, ...Munich, Germany) has overcome some of the limitations of classic thromboelastography. So far, no clinical validation on reproducibility (inter- and intra-assay variability) and sample stability over time has been published. Methods: To evaluate the pre-analytic aspects, sample stability over time was assessed in 48 patients in eight age groups. Citrated blood was stored at room temperature. Tests measured every 30 min from T 0 min up to T 120 min on two ROTEM® devices were INTEM (ellagic acid activated intrinsic pathway), EXTEM (tissue factor-triggered extrinsic pathway) and FIBTEM (with platelet inhibitor (cytochalasin D) evaluating the contribution of fibrinogen to clot formation). Precision by intra- and inter-assay variability was evaluated at two points of time in 10 volunteers. Finally, reference intervals and effect of age and sex were evaluated. Results: Blood was stable over 120 min and no significant differences in ROTEM® results were found. Maximum clot firmness measurements had a coefficient of variation of ≪3% for EXTEM, ≪5% for INTEM and ≪6% for FIBTEM. For clot formation time, the coefficient of variation was ≪4% for EXTEM and ≪3% for INTEM. Coefficient of variation for angle alpha was ≪3% for EXTEM and ≪6% for INTEM. The coefficient of variation for clotting time was ≪15% for both EXTEM and INTEM. Small but significant differences between ROTEM® devices were found for maximum clot firmness in FIBTEM and INTEM as well as clot formation time and alpha angle in INTEM. Conclusions: ROTEM® yields stable results over 120 min with a minimal variability on the same ROTEM® device. However, small but significant differences between ROTEM® devices were observed. Analysis should be performed on the same ROTEM® device if small differences are of importance for treatment.
BACKGROUND
Hyperfibrinolysis is a potentially life‐threatening condition associated with poor clot integrity and excessive bleeding. Although antifibrinolytics are an effective treatment, more ...liberal use of these drugs may lead to a prothrombotic risk, and an earlier and potentially safer treatment option would be desirable. Hyperfibrinolysis has been shown to be attenuated by in vitro supplementation of purified human Factor (F)XIII concentrate. Cryoprecipitate represents an alternative source of FXIII and the only approved source of concentrated FXIII in some countries. The aim of this study was to investigate whether cryoprecipitate, FXIII, and fibrinogen concentrate mitigate hyperfibrinolysis.
STUDY DESIGN AND METHODS
Ten citrate blood specimens from healthy subjects were spiked with tissue plasminogen activator (t‐PA) and subsequently supplemented with cryoprecipitate, FXIII, fibrinogen concentrate, and ɛ‐aminocaproic acid (EACA). Thromboelastometry tests were performed at baseline, after t‐PA, and after supplementation. Hyperfibrinolysis was assessed using the clot lysis index at 60 minutes (LI60; reciprocal of maximum lysis).
RESULTS
The LI60 was significantly improved (fibrinolysis attenuated) after cryoprecipitate supplementation compared to t‐PA alone and compared to FXIII and fibrinogen concentrate. Hyperfibrinolysis was only fully reversed using EACA. In addition, cryoprecipitate demonstrated the least variability in the attenuation of hyperfibrinolysis among 10 healthy subjects, compared to FXIII and fibrinogen concentrate.
CONCLUSION
This is the first study to show that cryoprecipitate is able to significantly mitigate hyperfibrinolysis in an in vitro model. Further investigations are warranted to determine whether cryoprecipitate may have a previously unrecognized benefit and should be administered earlier in resuscitation protocols.
Both congenital and acquired fibrinogen deficiency can be safely treated with administration of fibrinogen concentrate.
The aim of this study was to test the efficacy of a new fibrinogen product ...(Fibryga) compared to a licensed product (Haemocomplettan) in an in vitro model of dilutional coagulopathy.
Ten blood specimens from healthy volunteers were diluted 1:1 with balanced crystalloid solution and subsequently supplemented with each fibrinogen concentrate at a dose replicating in vivo supplementation (50 mg kg
−1
). Changes in clot firmness (FIBTEM and EXTEM assay), as well as changes in the fibrinogen antigen level, fibrinogen activity, factor XIII level and fibronectin levels were assessed at baseline, after dilution and after adding fibrinogen concentrate.
There was no significant difference between the drugs in their in vitro ability to improve clot firmness in the FIBTEM assay (Fibryga: mean MCF 14.4 mm (SD 3.4 mm) vs. Haemocomplettan: MCF 14.1 mm (2.4); p = .584). Fibryga led to significantly higher clot firmness in EXTEM MCF: 56.7 mm (3.8) vs. 53.7 mm (3.7); p < .001). Distinct differences between FXIII levels (significantly higher in Fibryga; mean 40.9% (6.2%) vs. 31.0% (6.2%); p < .001) and fibronectin levels (significantly higher in Haemocomplettan; mean 0.008 g L
−1
(SD 0.002 g L
−1
) vs. 0.002 g L
−1
(SD 0.002 g L
−1
; p < .001) were observed between products.
This is the first study to demonstrate that Fibryga and Haemocomplettan have similar efficacy in improving clot firmness in a dilutional hypofibrinogenemia model in vitro.
The viscoelastic functional fibrinogen (FF) and FIBTEM assays measure the contribution of fibrin to clot strength. Inhibition of platelet function is a necessary precondition for these tests to work. ...We investigated a novel test for measuring fibrin-based clotting, FIBTEM PLUS, in cardiac surgery and compared it with FF and FIBTEM.
A prospective, observational study was performed which included 30 patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Blood samples were drawn at the beginning of surgery (pre-CPB), approximately 20 minutes before weaning from CPB and 5 minutes after heparin neutralization. FF, FIBTEM, and FIBTEM PLUS tests were performed in duplicate for all blood samples. Additional coagulation parameters, including platelet count, plasma fibrinogen levels, factor XIII activity, and heparin concentration, were also recorded for each sample.
At all time points, the lowest mean maximum clot firmness (MCF) was observed with FIBTEM PLUS, although a statistically significant difference between FIBTEM and FIBTEM PLUS was observed only at baseline (mean values 22 vs 19 mm, P = 0.01; FF value for comparison: 27.7 mm). FF maximum amplitude (MA) values were significantly higher than FIBTEM MCF and FIBTEM PLUS MCF pre-CPB, during CPB and after heparin neutralization (P ≤ 0.001 for FF MA versus FIBTEM MCF and for FF MA versus FIBTEM PLUS MCF at all time points). The difference between FIBTEM MCF and FIBTEM PLUS MCF correlated with platelet count (r = 0.46;P < 0.001), whereas differences between FF MA and FIBTEM MCF, or FF MA and FIBTEM PLUS MCF did not (r = -0.07, P = 0.51; r = 0.16, P = 0.12, respectively). Differences between the assays were unrelated to heparin levels, which decreased considerably after protamine administration compared with heparin levels recorded before weaning from CPB (decrease from 2.1 to 0.1 U/mL and from 2.8 to 0.2 U/mL for anti-factor IIa and anti-factor Xa, respectively). Agreement between duplicate measurements was similar with FIBTEM and FIBTEM PLUS assays and lower with FF. Significant positive correlations were found between MCF or MA and fibrinogen concentration (all P < 0.001); the highest correlation was with FIBTEM PLUS MCF (r = 0.70).
The FIBTEM PLUS assay produces precise results. At baseline, it provides greater inhibition of platelets than FIBTEM, but there is no meaningful difference between FIBTEM PLUS and FIBTEM in patients with low platelet counts.
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