Roza Chaireti

Thrombin generation and D-dimer concentrations in a patient cohort investigated for venous thromboembolism. Relations to venous thrombosis, factor V Leiden and prothrombin G20210A. The LIST study

INTRODUCTION The present study evaluated possible relations between various markers of thrombin generation, D-dimer and venous thromboembolism in outpatients with and without the FV Leiden and the protrombin mutations. PATIENTS AND METHODS Our cohort consisted of 98 patients with the FV Leiden and 15 with the prothrombin mutation and an equal number of age- and gender-matched controls. All subjects were investigated due to suspicion of venous thromboembolism and the diagnosis was objectively confirmed or refuted. RESULTS We compared the D-dimer values and the thrombin generation markers among different patient groups (with/without thromboembolism, with/without genetic factors, gender-linked). The only statistically significant difference noted was prolonged time both for the initiation and termination of thrombin generation in patients with thrombosis. This applied to controls and to patients heterozygous for the FV Leiden. Additionally, the D-dimer values were elevated in patients with the FV Leiden. No difference was found among the patients with prothrombin mutation and their controls. DISCUSSION Multi-variant analysis indicated that the difference in D-dimer between FV Leiden patients and controls was due to the greater number of patients with confirmed thrombosis in the former group, a finding supported by an independent prospective study on postoperative thrombosis. Neither D-dimer concentration nor thrombin generation depend on FV Leiden. The total amount of thrombin generated was not related to diagnosis. The prolonged thrombin generation noted in controls and FV Leiden heterozygotes with thrombosis may point out different thrombin generation profiles in different patient populations and requires further studies.

Mutations in the isocitrate dehydrogenase 2 gene and IDH1 SNP 105C > T have a prognostic value in acute myeloid leukemia

BackgroundThe isocitrate dehydrogenase (IDH1/IDH2) genes are metabolic enzymes, which are frequently mutated in acute myeloid leukemia (AML). The enzymes acquire neomorphic enzymatic activity when they mutated.MethodsWe have investigated the frequency and outcome of the acquired IDH1/IDH2 mutations and the IDH1 SNP 105C > T (rs11554137) in 189 unselected de novo AML patients by polymerase chain reaction amplification followed by direct sequencing. The survival are presented in Kaplan Meier curves with log rank test. Multivariable survival analysis was conducted using Cox regression method, taking age, risk group, treatment, IDH1/2 mutations and IDH1 SNP105 genotype into account.ResultsOverall, IDH1/2 mutations were found in 41/187 (21.7%) of the AML patients. IDH1 codon 132 mutations were present in 7.9%, whereas IDH2 mutations were more frequent and mutations were identified in codon 140 and 172 in a frequency of 11.1% and 2.6%, respectively. The SNP 105C > T was present in 10.5% of the patients, similar to the normal population. A significantly reduced overall survival (OS) for patients carrying IDH2 codon 140 mutation compared with patients carrying wild-type IDH2 gene (p < 0.001) was observed in the intermediate risk patient group. Neither in the entire patient group nor subdivided in different risk groups, IDH1 mutations had any significance on OS compared to the wild-type IDH1 patients. A significant difference in OS between the heterozygous SNP variant and the homozygous wild-type was observed in the intermediate risk FLT3 negative AML patients (p = 0.004).ConclusionsOur results indicate that AML-patients with IDH2 mutations or the IDH1 SNP 105C > T variant can represent a new subgroup for risk stratification and may indicate new treatment options.

Increased thrombin generation in splanchnic vein thrombosis is related to the presence of liver cirrhosis and not to the thrombotic event.

INTRODUCTION In recent years there have been increasing evidence associating liver disease with hypercoagulability, rather than bleeding. The aim of the study was to evaluate the haemostatic potential in patients with liver disease. PATIENTS AND METHODS We measured thrombin generation in the presence and absence of thrombomodulin in patients with portal vein thrombosis (PVT, n=47), Budd-Chiari syndrome (BCS, n=15) and cirrhosis (n=24) and compared the results to those obtained from healthy controls (n=21). Fifteen patients with PVT and 10 patients with BCS were treated with warfarin and were compared to an equal number of patients with atrial fibrillation matched for prothrombin time-international normalized ratio. We assessed resistance to thrombomodulin by using ratios [marker measured in the presence/absence of thrombomodulin]. RESULTS There were no differences in thrombin generation between patients on warfarin treatment and their controls. Cirrhotic patients generated more thrombin in the presence of thrombomodulin and exhibited thrombomodulin resistance compared to controls [p=0.006 for endogenous thrombin potential (ETP) and p<0.001 for peak thrombin and both ratios ETP and peak] and patients with non-cirrhotic PVT (p=0.001, p=0.006, p<0.001, p<0.001 for ETP, peak, ratio ETP, ratio peak, respectively). The patients with cirrhotic PVT exhibited higher ETP (p=0.044) and peak (p=0.02) in the presence of thrombomodulin than controls, as well as thrombomodulin resistance (ETP and peak ratios: p=0.001). CONCLUSIONS Hypercoagulability and thrombomodulin resistance in patients with cirrhosis were independent of the presence of splanchnic vein thrombosis. The hypercoagulability in patients with cirrhotic PVT could have implications for considering longer or more intensive treatment with anticoagulants in this group.

TP53 mutations and MDM2(SNP309) identify subgroups of AML patients with impaired outcome

TP53 is commonly mutated in several cancers and confers treatment resistance and poor prognosis. Altered expression of mouse double minute 2 (MDM2), a negative regulator of p53, may also attenuate normal p53 signaling, thereby enhancing tumor transformation and resistance to apoptosis. The single nucleotide polymorphism (SNP) 309 has been reported to increase MDM2 expression and impair normal p53 response.

Endogenous thrombin potential is higher during the luteal phase than during the follicular phase of a normal menstrual cycle

STUDY QUESTION Do thrombin generation and haemostatic parameters differ during the two phases of the menstrual cycle? SUMMARY ANSWER Total thrombin concentration is higher during the luteal phase compared with the follicular phase of the menstrual cycle. WHAT IS KNOWN ALREADY The coagulation cascade is affected by many variables, such as fluctuations in the levels of sex hormones. The studies on the variations in haemostatic parameters during the menstrual cycle have produced diverse results. STUDY DESIGN, SIZE, DURATION Thrombin generation and selected haemostatic parameters (fibrinogen, factor II, factor VII, factor VIII, factor X, von Willebrand factor, antithrombin and D-dimer) were measured during the two phases of a normal menstrual cycle in 102 healthy women not taking any form of hormone medication. PARTICIPANTS/MATERIALS, SETTING, METHODS The study cohort consisted of 102 healthy women with regular menstrual cycles. Thrombin generation was measured by the calibrated automated thrombogram method. Progesterone and sex hormone-binding globulin were measured by chemiluminescence enzyme immunoassays. Estradiol was measured by a sensitive radioimmunoassay. Fibrinogen was measured by a clotting method, antithrombin was measured by a chromogenic method and factor II, factor VII, factor VIII, factor X, von Willebrand factor and D-dimer were measured by photometric methods. MAIN RESULTS AND THE ROLE OF CHANCE It was shown that the total amount of generated thrombin (Endogenous Thrombin Potential) was significantly higher during the luteal compared with the follicular phase (P = 0.027). Factor X was significantly higher during the follicular phase (P = 0.028). Progesterone exhibited significant associations (measured by the least squares regression analysis) with fibrinogen and factor X during the follicular phase (P = 0.043 and P = 0.033, respectively) and with factors II and VII during the luteal phase (P = 0.034 and P = 0.024, respectively). The validity of the results from the regression analysis was further confirmed by performing correlation analyses (Pearson correlation matrix) for haemostatic markers for the luteal and follicular phases (accepted correlation level >0.8). LIMITATIONS, REASONS FOR CAUTION The wide confidence interval for the differences in endogenous thrombin potential during the two phases could imply that the size of the cohort may not be sufficient to fully evaluate the biological variations. Additionally, the haemostatic markers were not shown to have significant associations with thrombin generation, suggesting that the increased thrombin concentration during the luteal phase would be mediated by another mechanism, as yet unidentified. WIDER IMPLICATIONS OF THE FINDINGS The associations between progesterone and the haemostatic markers, as shown for both phases of the menstrual cycle, suggest a previously unknown or undefined yet potentially significant role for progesterone in the coagulation system. However, it has been shown that the use of progestogen-only preparations does not affect the coagulation system, which is partly the reason why they are considered safe for women with thrombophilia or previous thrombotic event. Further studies are required in order to demonstrate whether our results can be extrapolated for synthetic progestins, which might have significant implication on the indications for their use.

Postpartum Hemorrhage in Women with Von Willebrand Disease – A Retrospective Observational Study

Introduction von Willebrand disease (VWD) is a hereditary bleeding disorder, caused by a deficiency in the levels and/or function of von Willebrand factor (VWF). Women with VWD appear to be at increased risk of experiencing postpartum hemorrhage (PPH), though the levels of VWF increase during pregnancy. There is limited knowledge of how PPH is associated with the subtype of VWD, plasma levels of other coagulations factors than VWF and given hemostatic treatment. Aims The aims were to investigate the incidence of PPH in women with VWD and to analyse the correlation between PPH and: (1) type of VWD, (2) laboratory monitoring of VWF and FVIII and (3) hemostatic drug treatment. Methods This was a retrospective observational study. The study participants (n = 34) were recruited from the Coagulation Unit, Karolinska University hospital. Fifty-nine deliveries, which occurred in 14 different obstetrics units (years 1995–2012) were included in the study. Results The incidence of primary PPH was 44%, severe primary PPH 20% and secondary PPH 12%. VWD type 3 was associated with a higher risk of experiencing severe primary PPH compared to other subtypes. FVIII:C in pregnancy was inversely correlated to blood loss during delivery. There was a significantly higher incidence of secondary PPH when the VWD diagnosis was unknown at time of delivery. Conclusions The women with VWD are at higher risk of PPH, especially those with type 3 VWD or when diagnosis is unknown prior to delivery. Identification of pregnant women with undiagnosed VWD may be of importance in order to prevent PPH.

Is thrombin generation at the time of an acute thromboembolic episode a predictor of recurrence? The LInköping Study on Thrombosis (LIST) – A 7-year follow-up

INTRODUCTION Venous thromboembolism (VTE) is considered a chronic disease, since a high percentage of patients experience recurrences. Oral anticoagulants are effective in preventing recurrences at a price of potential bleeding complications, which underlines the importance of finding reliable markers for estimating the individual recurrence risk. In this report we evaluate thrombin generation markers at the time of an acute VTE as predictive markers for recurrence risk. Gender, presence of factor V Leiden and acquired provocative factors were taken into consideration. Additionally, we study the correlation between thrombin generation at the time of an acute VTE and thrombin generation measured four to eight weeks after discontinuation of anticoagulants. MATERIALS AND METHODS The main cohort consisted of 115 patients with a confirmed thromboembolic event at inclusion. The follow-up period was seven years. RESULTS Patients with an initial unprovoked VTE and at least one recurrence had significantly prolonged thrombin generation, whereas those without recurrences had higher maximum and total thrombin concentration. In contrast, when thrombin generation was measured one to two months after discontinuation of anticoagulant treatment, it was shown that the patients who experienced recurrences had higher maximum thrombin concentration. CONCLUSIONS Our study shows that thrombin generation profiles at the time of a VTE correlate to the clinical course after the acute episode. The great over-lap in thrombin generation between patients with and without recurrences though, makes the use of thrombin generation profiles for advice on length of oral anticoagulation for an individual patient doubtful at the present stage of knowledge.

Risk factors and obstetric outcomes in pregnancies complicated by pelvic vein thrombosis, and in the subsequent pregnancy

Pelvic vein thrombosis has a much higher incidence during pregnancy compared to the incidence in the non-pregnant population [1]. This single-centre, retrospective study aims to examine risk factors, as well as obstetric and foetal outcomes, in women with antepartum pelvic vein thrombosis and their high-risk subsequent pregnancies [2], and evaluate the efficacy and safety of anticoagulant treatment and thromboprophylaxis as determined by the guidelines issued by the Swedish Society for Obstetrics and Gynaecology [3].

TP53 mutations and MDM2 single nucleotide polymorphism 309T-G predicts outcome and treatment resistance in acute myeloid leukemia

TP53 mutations and MDM2 single nucleotide polymorphism 309T-G predicts outcome and treatment resistance in acute myeloid leukemia