Evaluation of the DOAC-Stop Procedure by LC-MS/MS Assays for Determining the Residual Activity of Dabigatran, Rivaroxaban, and Apixaban.

The effect of direct oral anticoagulants (DOACs) on laboratory tests dependent on the production of their targets, factor IIa and factor Xa (FXa), is a well-known problem and can cause both false positive and negative results. Therefore, the correct interpretation of tests performed in patients receiving DOACs is necessary to avoid misclassification and subsequent clinical consequences. However, even with significant experience, there are situations where it is not possible to assess the influence of some methods. Particularly important is the situation in the diagnosis of lupus anticoagulants using the dilute Russell viper venom timetest, which is based on direct FXa activation. A very promising solution to this situation is offered by the DOAC laboratory balancing procedure DOAC-Stop. For evaluating the effectiveness of this procedure, 60 (20 apixaban, 20 dabigatran, and 20 rivaroxaban) patients treated with DOACs were enrolled. All patient samples were analyzed for the presence of individual DOAC types and subsequently subjected to the DOAC-Stop procedure.We evaluated its effectiveness by our own high-performance liquid chromatography-coupled tandem mass spectrometrymethod, which simultaneously sets all high-sensitivity DOACs. Unlike coagulation tests based on the determination of the residual effects of DOACs on target enzymes, which is complicated by extensive interindividual variation, this methodology is highly specific and sensitive.The DOAC-Stop procedure eliminated dabigatran from 99.5%, rivaroxaban from 97.9%, and apixaban from 97.1% of participants in our group. Residual amounts did not exceed 2.7 ng/mL for dabigatran, 10.9 ng/mL for rivaroxaban, or 13.03 ng/mL for apixaban, which are safe values that do not affect either screening or special coagulation tests.

Thrombin Generation Testing in Patients with Myelofibrosis.

BACKGROUND: Primary myelofibrosis (PMF) is a chronic clonal myeloid disorder. Together with essential thrombocythemia (ET) and polycythemia vera (PV), it belongs to a group of Philadelphia chromosome-negative myeloproliferative neoplasms. Thrombotic events are serious complications negatively influencing the quality and length of these patients' lives. The confirmed risk factors for venous thromboembolism are age over 60 years, a positive history of thromboembolism, presence of common cardiovascular risks, JAK2 V617F mutation and, according to some authors, leukocytosis. Various opinions on the role of thrombocythemia have been published. The present study was undertaken to evaluate the benefit of thrombin generation test and its potential use in predicting the risk of thrombosis in MF patients. METHODS: The analysis included plasma samples obtained from 36 patients diagnosed with MF in our center from 2004 to 2016 (JAK2 V617-positive 53%; CALR-positive 31%; MPL-positive 14%; triple negative 2%) and a control group comprising 20 healthy volunteer blood donors. Thrombin generation was measured in platelet-rich plasma using the TECHNOTHROMBIN® TGA kit (Technoclone, Austria) and the fully automated system Ceveron® Alpha (Technoclone). The results were correlated with clinical and laboratory parameters of the patients. RESULTS: There were differences in thrombin generation as expressed by endogenous thrombin potential (ETP) between patients and healthy controls, with ETP being lower in the patient group (p = 0.0003). Analysis confirmed a significant correlation between thrombin generation and platelet counts, with higher thrombin generation in patients with thrombocythemia > 400 x 109/L (p = 0.04). ETP values were consistently higher in earlier disease stages and lower in CALR-mutated myelofibrosis. CONCLUSIONS: In MF patients, thrombin generation is mainly influenced by platelet counts and, to a lesser extent, by mutation status, activity, and progression of the disease. Thrombin generation test results have confirmed that thrombocythemia is a potential risk factor for thrombotic complications.

Validation of a New Panel of Automated Chemiluminescence Assays for Anticardiolipin Antibodies in the Screening for Antiphospholipid Syndrome.

BACKGROUND: Antibodies anticardiolipin (aCL) and anti-ß2-glycoprotein I (aß2GPI) are two of three laboratory criteria of antiphospholipid syndrome (APS). All of assays of antiphospholipid antibodies (aPL), coagulation assays as well as ELISAs, show methodological shortcomings, that affect their sensitivity and specificity. Therefore, we decided to validate these parameters for a new chemiluminescent examination (CLIA). METHODS: aCL and aß2GPI antibodies were measured by ELISAs (AIDA, Bad Kreuznach, Germany) and aß2GPI with CLIA kits (Werfen, Barcelona, Spain). RESULTS: When we evaluated both assays, the coefficient of variation for CLIA was slightly lower (9.04 - 12.74%) than for ELISA (11.05 - 15.3%) and the LOD was 0.2 U/L. The dilution series showed significant linearity for all CLIA methods, aCL IgG, aCL IgM, aß2GPI IgG, and aß2GPI IgM (0 - 3000 U/L), and method comparison studies revealed good agreement with the currently used ELISA (Kappa values ranging 0.534 - 0.936) without determination of aß2GPI IgG. The determination aß2GPI IgG by CLIA method shows higher positivity in 31 samples. These new aCL IgG, aCL IgM, aß2GPI IgG, and aß2GPI IgM tests have excellent analytical characteristics and allow fully automated and simultaneous analysis on an analyzer. CONCLUSIONS: Chemiluminescent determination of an automated analyzer can improve the fundamental parameters of tests such as reproducibility between laboratories.

Detection of clopidogrel resistance using ADP induced aggregometry with specific inhibitor PGE1.

BACKROUND: Antiaggregation therapy is still the most frequently used approach to prevent thrombotic events in cardiovascular diseases. It has a good clinical effect but increasing evidence shows high residual platelet aggregation activity in a number of patients. Laboratory methods only allow us to detect clopidogrel "non-responders" or "low responders". Recent methods are based on monitoring residual platelet aggregation activity (aggregation methods) or detecting the number of free epitopes for binding a specific monoclonal antibody such as vasodilator-stimulated phosphoprotein phosphorylation (VASP). METHODS: The aims of our study were comparison light transmission aggregometry (LTA) and multiple electrode platelet aggregometry (MEA) with induction by ADP in concentrations of 20 micromol/L with or without prostaglandin E1 (PGE1) for monitoring clopidogrel resistance. RESULTS: In the group of 84 patients with cardiovascular disease (CAD) studied, an impaired individual response to clopidogrel therapy was found 11.9% and 10.7% of the patients using MEA and LTA, respectively, induced by ADP with PGE1. The LTA and MEA methods with induction by ADP with PGE1 and without PGE1 were statistically compared using Spearman's nonparametric correlation analysis. Both methods with using PGE, showed a positive significant correlation (p = 0.003) in contrast with the results without PGE1 with a no significant correlation (p = 0.732). CONCLUSIONS: The sensitivity for detecting clopidogrel resistance correlates well with other data in the literature suggesting that there are 5%-30% clopidogrel low-responders depending on the type of platelet function assay used and the criteria for defining a low-responder [16-18]. These results favor implementation of the ADP test with PGE1 by MEA specifically for identification of low-responders to clopidogrel.

The advantages and limitations of impedance aggregometry in detection of heparin-induced thrombocytopenia.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) represents a serious complication of heparin treatment. IgG antibodies binding platelet factor 4 (PF4) and heparin trigger the clinical manifestations of HIT. However, only a portion of the antibodies have the ability to activate platelets, and these can be identified by a platelet aggregation test (functional testing). Current methods HIPA and SRA are time-consuming and difficult if HIT is clinically suspected; therefore, numerous new methods have recently been developed. METHODS: To determine HIT, impedance aggregometry using the Multiplate analyzer (MEA) as heparin-induced aggregation techniques and the Technozym HIT Ig ELISA test were used. The MEA method uses sensitization of donor platelets with patient plasma in the presence of heparin at a concentration of 0.5 IU/mL. The results were compared with the ELISA test. RESULTS: We examined 190 patients at clinically intermediate and higher risk of HIT according to the 4T score. All samples were examined by the ELISA test and MEA, with positive samples being further confirmed by high-concentration heparin. The methodology was modified with respect to the dilution for high positive samples and assessment has been extended to an index of inhibition. CONCLUSIONS: In the studied group, we demonstrated that MEA has sufficient sensitivity and higher specificity. In the group of patients, 10.0% showed positive results by MEA as compared with 7.3% determined by ELISA. Unlike the ELISA methods of the same quality, MEA is more suitable for detecting platelet-activating HIT antibodies in practice.

[Occurence, etiology and clinical significance of trombocytopenia in pregnancy]. / Incidence, etiologie a klinický význam trombocytopenie v gravidite

OBJECTIVE: The principal objective of the study is to compare results from the experimental group of pregnant women suffering from thrombocytopenia in pregnancy with results from the control group of pregnant women with normal physiologic blood platelet count. SETTING: Department of Obstetrics and Gynaecology of the Tomas Bata Regional Hospital Zlín, Obstetrics and Gynaecology Clinic, Haematology and Oncology Clinic of the Palacky University Teaching Hospital and Medical School in Olomouc, Obstetrics and Gynaecology Clinic of the Ostrava Teaching Hospital. METHODOLOGY: A group of 200 pregnant women suffering from thrombocytopenia underwent thorough medical tests. The level of platelets, presence of anti-platelets agents, liver function (LFT), anti-phospholipid antibodies, complete blood count with differential, specific antibodies for hepatitis B and C, Lyme borreliosis and cytomegalovirus were determined from venous blood using the EIA, ELISA methods. RESULTS: Medical articles and books about thrombocytopenia divide the causes for thrombocytopenia as follows: 79.5% benign gestational thrombocytopenia, 16% preeclampsia, 2.5% HELLP syndrome, 1% immune thrombocytopenia, 1% HVC. The number of women who developed physiological anaemia in pregnancy and were overweight is identical in the experimental group of pregnant women suffering from thrombocytopenia and in the control group of pregnant women with normal physiologic blood platelet count, and the proportion of the different age groups in the two groups of pregnant women is also identical. CONCLUSION: 32% of pregnancies in the experimental group ended in a caesarean section, of which 13.5% in a group of 127 pregnant women suffering from mild thrombocytopenia, 17.5% in a group of 71 pregnant women suffering from moderate thrombocytopenia and 1% in a group of 2 pregnant women suffering from severe thrombocytopenia. 20.5% pregnancies in the control group ended in caesarean section.

[Preeclampsia and thrombin generation test]. / Preeklampsie a trombin generacní test.

OBJECTIVE: Acquiring new information to allow prediction of the development of diseases associated with impaired coagulation. Design effective preventive measures most serious diseases (TEN) in the fields of gynecology and obstetrics. For pregnant women with preeclampsia, hypertension compared with women with normal pregnancies could lead to increased thrombin generation due to the synergistic effect of thrombotic risk factors. Based on the results and found statistically significant differences between the groups among pregnant can select for a higher risk of developing deep vein thrombosis. This risk group could then greatly benefit from more stringent follow-up and possible preventive treatment prophylactic doses of LMWH in reducing maternal and perinatal morbidity and mortality. DESIGN: Prospective study. SETTING: Department of Obstetrics and Gynecology, University Hospital Olomouc. METHODS: In early pregnancy - during pregnancy standard samples (up to the end of the first trimester) patients venous blood was sampled and they completed information questionnaire. A second sampling was carried out between 24 to 28 week, the third sample and between 36th to 40th week. Obtained blood samples were subsequently processed in the coagulation laboratory Hemato-Oncology Clinic and Olomouc. The blood samples were investigated protein C and S, antithrombin, FVIII level, FII, Leiden, and plasma endothelial microparticles, and lupus anticoagulant and APC resistance standardized methodologies. Thrombin generation was determined thrombin generation test. Thrombin generation was measured fully automatically using a kit (Technothrombin TGA, Technoclone, Vienna, Austria) and analyzer Ceveron Alpha (Technoclone, Vienna, Austria) with fully automatic analysis software. As the main parameter is evaluated by the maximum thrombin generation, at the same time, however, was also detected in the total amount of thrombin and the time until the beginning of the formation of thrombin. RESULTS: In the period 2008-2011 were analyzed blood samples of 303 healthy pregnant women. 215 women, ie 71% were nuliparas, 60 women, ie 19.8% were primiparas, 28 women, 9,2% were secundiparas. The average age of pregnant women was 28.6 years(± 3.8 years). The average maternal weight at the beginning of pregnancy was 63.6 kg (± 7.8 kg). Of the 303 women in 18 (6%) developed slight to moderate degree of preeclampsia or HELLP syndrome with varying severity of clinical manifestations. 20 mothers (6.6%) gave birth prematurely terminated before 37 week of pregnancy. 3 pregnancies (0.9%) were discontinued due to genetic indication for fetal birth defect. The complete study protocol (sampling in all three trimesters) thus completed 280 pregnancies. Of the three evaluated, parameter Lag time, ETP and peak we observed significant differences when comparing physiological pregnancies and pregnancies with preeclampsia (Table 3 and Figure 5-7), the statistical level of p < 0.01. In pregnancies with chronic hypertension, these differences were not significant. Comparison of 18 pregnancies, in which the III. trimester developed preeclampsia with other pregnant with physiological pregnancy did not show statistically significant differences in I. and II. trimester. The results suggest the activation of coagulation through the late stages of pregnancy. Results are influenced by strong clinical variability of disease. In severe and early preeclampsia this activation and significant differences begin much earlier. CONCLUSION: We demonstrated significantly higher activation of thrombin generation in women with preeclampsia [10]. Changes in preeclampsia are characterized by increased generation of thrombin in plasma. This fact may explain the partial success of the clinical use of aspirin in preeclampsia. In the third trimester, during the manifestation of the disease, patients with preeclampsia have significantly higher ETP compared to patients with a normal pregnancies. Pregnant women with chronic hypertension also show a slight increase in the activation of thrombin. However, these results are not statistically significant. Examination of coagulation in the first and second trimester in women who later developed preeclampsia, showed no statistically significant differences and thus can not be used in this case as predictive, but only as a diagnostic test.

[Endothelial dysfunction in pregnancies with chronic hypertension]. / Dysfunkce endotelu u tehotných s chronickou formou hypertenze.

AIM OF THE STUDY: To establish endothelial activation markers which could uncover endothelial damage during hysiological pregnancy and pregnacies with chronic hypertension. SETTINGS: Department of Hemato-oncology, Obstetrics and Gynecology and Department of Medical Genetics and Fetal Medicine Medical Faculty of Palacký University Olomouc, Department of Obstetrics and Gynecology Medical Faculty Ostrava. METHODS: We examined 298 pregnant women with a physiological pregnancy. Venous blood samples were collected from the women in both arms at the beginning of the pregnancy, a second sample was collected in the interval 24-28 weeks gestation, the third sample was colected about the 36 weeks of gestation. Parameters were examined using methods: t-PA - ELISA, PAI-1 - ELISA, vWF - EIA, ePCR - ELISA, MMP-2,9 - ELISA with fluorogenic detection, TIMP-2 - ELISA, endothelial microparticles - flow cytometry. RESULTS: In accordance with the literature, we have observed in our study significantly increased endothelial activatition in hypertensive pregnancies compared with women with physiological pregnancy, as evidenced by significant increases in vWF activity and antigen, thrombomodulin and PAI-1 in all trimesters. In the other investigated parameters statistically significant changes were not observed. CONCLUSION: We have found significant signs of endothelial dysfunction in the group of women with pre-existing hypertension, a wide range of parameters examined markers indicating an significantly increased endothelial activation pregnant women with pre-existing hypertension, confirming the need for strict follow-up of pregnant women with hypertensive disease.

[The occurence of genetic trombophilic markers in patients evaluated for infertility]. / Výskyt vybraných geneticky podmínených trombofilních markeru u pacientek podstupujících lécbu neplodnosti.

OBJECTIVE: To assess and compare the frequency of selected gene mutations of thrombophilic markers (FV Leiden, FII prothrombin G20210A and MTHFR C677T) in patients with primary and secondary infertility. DESIGN: Retrospective study. SETTING: Institute of normal anatomy, Faculty of Medicine and Dentistry, Palacky University Olomouc. METHODS: The study included 92 patients with primary infertility and 89 patients with secondary infertility. Indications for examination of these mutations were following: a positive family or personal history, a positive obstetrical history or a repeated failure of assisted reproduction treatment. RESULTS: According to our anticipation, women with the secondary infertility were significantly older(p < 0.0005) than those with primary infertility. No mutations of genes of examined thrombophilic markers (FV, FII and MTHFR), either alone or in combination, were found in only 8.7 % patients with primary infertility and in 5.6 % patients with secondary infertility. Significantly higher frequency of factor Leiden(p < 0.02) was observed in women with secondary infertility. There were no significant differences in the frequency of detected mutations of the remaining factors. CONCLUSION: Based on our findings we suggest that the assessment of selected gene mutations of thrombophilic markers should be a part of the diagnostic algorithm in patients with positive history for thrombophilic disorders.

[Thrombin generation test at physiological and risk gravidity]. / Trombin generacní test u fyziologické a rizikové gravidity.

UNLABELLED: Generation of thrombin is pivotal step of hemostasis, according to in vitro experiments, thrombin generation occurs in 2 phases. Initially small amount of thrombin is produced after activation of factor X by complex TF/FVIIa. Thrombin multiplies coagulation by activation of platelets, F V a F VIII. Complex of TF/FVIIa activates also F VIII a, F IX, F VIII and FIXa and its binding to surface of platelets, which activates F X and products quantity of thrombin and leads formation of fibrin and finaly to triggering clotting. DESIGN: Review. SETTING: Department of Obstetrics and Gynecology, University Hospital Olomouc.

The assessment of aspirin resistance by using light transmission and multiple electrode aggregometry.

INTRODUCTION: The issues related to aspirin [acetylsalicylic acid (ASA)] resistance are still under debate. Depending on the method of assessment and studied patients, the prevalence of ASA resistance is rather heterogeneous, ranging from 5% to 45%. The method most commonly used for assessing platelet function is their aggregation. ASA irreversibly inhibits cyclooxygenase-1 (COX-1) by acetylation. METHODS: This study aimed to compare light transmission aggregometry (LTA) and multiple electrode aggregometry (MEA) for the measurement of ASA resistance, using arachidonic acid as an inducer of the reaction. RESULTS: The study comprised 101 patients with stable ischemic heart disease taking a daily dose of 100 mg of ASA. The rates of ASA resistance were 22.22% and 21.21% as detected by LTA and MEA, respectively. The two methods were statistically compared using Spearman's nonparametric correlation analysis, with a positive significant correlation (P=0.01) and medium positive dependence between the methods (r=0.0539). CONCLUSION: If ASA resistance is detected by laboratory tests, replacement of ASA or its combination with other antiplatelet drugs as well as increased dosage may be considered.

[Monitoring of endothelial activation markers during physiological pregnancy]. / Monitorování hladin markeru aktivace endotelu behem fyziologické gravidity.

AIM OF THE STUDY: To establish endothelial activation markers which could uncover endothelial damage during physiological pregnancy. TYPE OF STUDY: Prospective study. METHOD: We examined 403 pregnant women with a physiological pregnancy. Venous blood samples were collected from the women at the beginning of the pregnancy, a second sample was collected in the interval 24-28 weeks gestation. Parameters were examined using methods: t-PA--ELISA, PAI-1--ELISA, vWF Ag--EIA ePCR--ELISA, MMP-2,9--ELISA with fluorogenic detection, TIMP-2--ELISA, endothelial microparticles - flow cytometry. RESULTS: The level of vWF antigen increased during the entire course of pregnancy (in the I. trimester the average level was 152.32%, in the II. and III. trimester 173.34% and 216.20% respectively). At the same time, vWf activity also increased (I. trimester average level 130.20%, II. and III. trimester 150.09% and 181.91% respectively). The level of thrombomodulin significantly increased during pregnancy (I. trimester average level 19.05 ng/ml, II. and III. trimester 28.47 ng/ml and 39.86 ng/ml respectively). The level of soluble form of EPCR increased during pregnancy (I. trimester average level 201.76 ng/ml, II. and III. trimester 274.68 ng/ml and 324.07 ng/ml respectively). The level of PAI-1 increased during the entire course of pregnancy (I. trimester average level 36.14 ng/ml, II. and III. trimester 50.07 ng/ml and 60.12 ng/ml respectively). The level of t- PA did not change significantly during the course of pregnancy (I. trimester average level 2.48 ng/ml, II. and III. trimester 2.97 and 3.34 ng/ml respectively). The levels of MMP-2 (I. trimester average level 9043.76 RFU, II. and III. trimester 9315.38 and 8800.27 RFU respectively), MMP-9 (I. trimester average level 8371.90, II. and III. trimester 8290.81 and 7470.50 respectively), TIMP-2 (I. trimester average level 92.5 ng/ml, II. and III. trimester 98.5 and 96.5 ng/ml respectively) or endothelial microparticles (I. trimester average level 3838.38 particles/microl, II. and III. trimester 3836.59 and 3650.59 particles/microl respectively) did not change significantly throughout the individual trimesters. CONCLUSION: We confirmed the hypothesis regarding the significant influence pregnancy has on changes in levels of these markers.

[Molecular methods in thrombophilic states diagnostics]. / Molekulární metody v diagnostice trombofilních stavu.

Molecular genetic methods passed into the field of investigation of thrombophilic states in 90th years of last century, along with the first discoveries of coagulation inhibitors (AT III, protein C and protein S). They have acquired a widespread use above all with the detection of the molecular basis of activated protein C (APC) resistance in 1994 by prof. Bertina. At the present time, a wide range of molecular genetic markers, linked with a clearly documented increased risk of thrombophilia are adapted. They include mutations of factor V Leiden 506R/Q, of protrombin 20210G/A, MTHFR 677C/T in homozygous form, mutation of PAI-1 4G/5G, mutations of different coagulation inhibitors and finally a range of polymorphisms with still not precisely defined increased risk for thrombophilia (F XIII Val34leu, platelets glycopeproteins, endothelial protein C receptor and trombomodulin). From the methodological viewpoint, all these techniques are based on the principle polymerase chain reaction (PCR). In the last period of time, however there was a rapid evolution, allowing a significant improvement in their laboriousness. Nowadays, splitting with the aid of restriction endonucleases, real time PCR or allel specific primers for PCR. The second, where molecular genetic methods are currently under use, is pathophysiological investigation of the single coagulation processes. Here, in a fact, most significant progress has been in the field of APC resistance made elucidation. Although still in the 90th years of the past century the genetical cause of these coagulation disturbance was unequivocally documented its clinically heterozygous appears not yet fully understood at the moment. Similarly, in prothrombin mutation, only the latest investigations have outlined the probable mechanism of expression. Concerning the future evolution of molecular genetic methods, there can be observed a clear cut tendency to better understanding the pathophysiologic cause of thrombophilia in comparison with the searching for new coagulation defects which consecutively bear lesser a relative risk of thrombosis.