Thromboelastography, whole-blood haemostasis and recurrent miscarriage

Measurement of Blood Viscoelasticity Using Thromboelastography

Thromboelastography (TEG) was the first viscoelastic test (VET), invented in Germany in 1948 by Dr. Hartert, and which evaluates the hemostatic competence of whole blood. Thromboelastography was introduced before the activated partial thromboplastin time (aPTT), which was devised in 1953. TEG was not widely used until the introduction of a cell-based model of hemostasis (1994) showing the importance of platelets and tissue factor in hemostasis. Nowadays, VET has become an essential method for assessing hemostatic competence in cardiac surgery, liver transplantation, and trauma. TEG has undergone several modifications, but the concept on which the original TEG was based (cup and pin technology) remained in up to the TEG 5000 analyzer (Haemonetics, Braintree, MA). A new generation of thromboelastography, TEG 6s (Haemonetics, Boston, MA), that assesses blood viscoelastic properties by resonance technology has recently been developed. This newer methodology represents a cartridge-based, automated assay aimed to improve on historical TEG performance and precision. In the present chapter, we will review the advantages and limitations of TEG 5000 and TEG 6s systems as well as factors that affect TEG and which must be considered when interpreting TEG tracings.

Genetic analysis of ANXA5 haplotype and its effect on recurrent pregnancy loss

Recurrent pregnancy loss (RPL) is often associated with dysregulated Annexin A5 (ANXA5) expression. Moreover, the variants of Anxa5, a protein that is enriched in the placenta to prevent coagulation, have been reported to affect RPL risks. The haplotypes M1 [including single nucleotide polymorphisms (SNPs) 1A/C and 27T/C] and M2 (including SNPs 19G/A, 1A/C, 27T/C and 76G/A) of ANXA5 were also reported to affect RPL risks. The present study aimed to investigate the association between the haplotype located in the promoter region of ANXA5 and the risk of RPL. Patients with RPL (n=235) or intrauterine fetus death (IUFD; n=154), as well as healthy control subjects (n=375) were enrolled in the current research. Their haplotypes of ANXA5 were determined using genotyping, and the association between ANXA5 haplotypes and the risk of RPL was accordingly analyzed. A luciferase assay was conducted to investigate the haplotype responsible for ANXA5 activity. Reverse transcription‑quantitative PCR, western blot analysis, immunohistochemistry and ELISA were performed to assess the expression level and activity of ANXA5 in patients with RPL. Consequently, the majority (n=214) of patients with RPL had a history of early RPL, whereas 31 patients with RPL had a history of both early and late RPL episodes. A significant difference was found between cases and controls in terms of gravidity and parity, whereas no significant differences were found in terms of age. The percentage of patients with RPL carrying the M2 haplotype of ANXA5 was significantly higher compared with that in control subjects, indicating that the M2 haplotype of ANXA5 was an independent risk of RPL as it influenced the transcription efficiency of ANXA5 promoter. In patients with RPL, ANXA5 activity was suppressed and the mRNA and protein expression levels of Anxa5 were decreased. Thus, the ANXA5 M2 haplotype may be an independent risk factor of RPL by affecting Anxa5 activity.

Diagnostic Value of Thromboelastography (TEG) for the Diagnosis of Death in Infected Patients

In this study, we want to investigate the clinical value of each index of thromboelastography (TEG) on the prognosis of infected patients.The clinical baseline data and TEG test results of 431 infected patients in our hospital's emergency department between January 2018 and December 2018 were selected. And the patients were divided into death and survival groups to analyze the predictive value of each index of TEG and the joint model on the death of infected patients.In the correlation study of C-reactive protein (CRP) and procalcitonin (PCT) with each TEG parameter, CRP was positively correlated with maximum amplitude (MA, r  =  0.145, P  =  .003) and elasticity constants (E, r  =  0.098, P  =  .043), respectively. PCT was positively correlated with coagulation reaction time (R, r  =  0.124, P  =  .010) and time to MA (TMA) (r  =  0.165, P  =  .001), respectively; PCT was negatively correlated with α-Angle (r  =  0.124, P  =  .010) and coagulation index (CI, r  =  -0.108, P  =  .026), respectively. Multifactorial regression analysis showed that granulocytes, thrombocytes, platelet distribution width (PDW), and infection site were independent influences on infected patients' death. Diagnostic data showed that all eight TEG indicators had good specificity for predicting death, but all had poor sensitivity; thrombodynamic potential index (TPI) had the best diagnostic value (area under the curve, AUC  =  0.609, P  =  .002). The eight-indicator modeling of TEG showed that the TEG model combined with PCT and CRP, respectively, had lower diagnostic efficacy than PCT (AUC  =  0.756, P < .001); however, TEG had better specificity (82.73%) when diagnosed independently.The granulocytes, thrombocytes, PDW, and infection site are independent influencing factors of death in infected patients. Each index of TEG has better specificity in the diagnosis of death in infected patients.

Prognostic analysis of antibody typing and treatment for antiphospholipid syndrome-related recurrent spontaneous abortion

OBJECTIVE

To determine the efficacy of antibody typing and treatment on live birth rate in Chinese patients with antiphospholipid syndrome (APS)-related recurrent spontaneous abortion (RSA).

METHODS

A retrospective study analyzed 4542 Chinese patients who experienced spontaneous abortion, of whom 314 had APS (272 primary and 42 secondary). Type of antibodies was tested. Anticoagulant and anti-inflammatory treatments were adopted according to the titer and type of antibodies. The incidence of repeated abortion and placental dysfunction, gestational age, and mean weight of the fetuses were recorded.

RESULTS

Among the patients with APS-related RSA, primary APS accounted for the largest proportion. The proportion of antibody classification was as follows: β2-glycoprotein 1 (β2GP1)-IgM (151, 48.08%), lupus anticoagulant (LAC) (36, 11.46%), anticardiolipin (aCL)-IgM (32, 10.19%), β2GP1-IgM and aCL-IgM (29, 9.23%), and aCL-IgG (16, 5.09%). After treatment, the negative conversion of antibody, including β2GP1-IgM and LAC, significantly improved pregnancy outcomes. There was no significant difference in pregnancy outcomes between the other antibody titers.

CONCLUSION

The combination of anticoagulant and anti-inflammatory treatment led to a higher live birth rate in the treatment of APS-related RSA, highlighting the potential of antibody typing in providing clinical guidance for the treatment of APS-related RSA.

Systematic review of viscoelastic testing (TEG/ROTEM) in obstetrics and recommendations from the women's SSC of the ISTH

Thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are point-of-care viscoelastic devices that use whole blood samples to assess coagulation and fibrinolysis. These devices have been studied extensively in cardiac surgery, but there is limited robust evidence supporting its use in obstetrics. The hesitancy toward its routine use in obstetrics may be due to the current lack of randomized controlled trials and large observational studies. The study aims to systematically review studies that investigated TEG/ROTEM use in pregnancy or peripartum, and to provide recommendations for future studies to fill current research gaps. We performed a systematic review of studies on viscoelastic testing in obstetrics. Included studies were original research, used TEG or ROTEM during pregnancy or peripartum, and published in English. Ninety-three studies, spanning 31 years from 1989 to 2020 and with a total of 32,817 participants, were included. Sixty-two (66.7%) of the studies used TEG and 31 (33.3%) used ROTEM. To date, there are a total of two randomized controlled trials on TEG/ROTEM use in obstetrics. ROTEM may be used to guide transfusion therapy for postpartum hemorrhage. TEG and ROTEM can detect the hypercoagulable changes associated with pregnancy. Variability between study protocols and results suggests the need for future large prospective high-quality studies with standardized protocols to investigate the utility of TEG/ROTEM in assessing risk for thrombosis and hemorrhage as well as in guiding prophylaxis and treatment in obstetric patients. This review identifies the gaps and provides concrete recommendations for future studies to fill those gaps.

Hydroxychloroquine may be beneficial in preeclampsia and recurrent miscarriage

Recurrent miscarriage (RM) and vasculoplacental disorders, such as preeclampsia (PE), affect women of childbearing age worldwide. Vascular endothelial dysfunction and immunological impairment are associated with both RM and PE. To date, there is no effective or optimal therapeutic approach for these conditions. Notably, aspirin use is only partially effective in the prevention of PE. Hydroxychloroquine (HCQ) has demonstrated beneficial effects on disease flares, pregnancy outcomes and cardiovascular impairment in systemic erythaematosus lupus (SLE) through its immunomodulatory, vasculoprotective and antithrombotic properties. Here, in the context of the underlying physiological dysregulation associated with PE and RM, the beneficial properties and potential therapeutic efficacy of HCQ are reviewed in anticipation of the results of current and future trials. Two related trials addressing RM in the absence of maternal autoimmune disease are ongoing. Other trials addressing pregnancy outcomes in the presence of maternal autoimmune disease are forthcoming. In this review, we hypothesise that the immunological and endothelial effects of HCQ may be beneficial in the context of PE and RM, regardless of the maternal autoimmune status.

Predictive value of thromboelastography parameters combined with antithrombin III and D-Dimer in patients with recurrent spontaneous abortion

PROBLEM

To investigate the value of thromboelastography (TEG) combined with antithrombin III (AT-III) and D-Dimer in predicting the occurrence of recurrent spontaneous abortion (RSA).

METHOD OF STUDY

One hundred and five RSA patients and 40 fertile women were enrolled. The subjects were subjected into four groups: group 1 (40 fertile women), group 2 (58 women with 2 abortions), group 3 (30 women with 3 abortions), and group 4 (17 women with four abortions). TEG was conducted on all subjects. Clotting time, reaction time, angle degree, coagulation index, and maximum amplitude were measured. The levels AT-III, D-Dimer, platelet counts, and fibrinogen concentration were determined. The ROC curve analysis was done using MedCalc software to analyse the diagnosis accuracy of the parameters of interest and the combined approach.

RESULTS

The AT-III level in all group 4 was significantly lower than in fertile women. The D-Dimer concentration, platelet count, and MA in patients with four prior abortions were significantly higher than the other three groups. CI and fibrinogen concentration in patients with four prior pregnancy losses were significantly higher than group 1. The ROC curves suggested that combined use of CI, MA, AT-III, and D-Dimer was with the highest accuracy 92.8%, thus predicting the most accurate diagnosis for RSA.

CONCLUSION

Recurrent spontaneous abortion is associated with abnormal coagulation and anticoagulation. TEG combined with detection of AT-III and D-Dimer levels can distinguish patient with RSA from those with normal fertility and highly possibly predict the occurrence of RSA.

Hydroxychloroquine for prevention of recurrent miscarriage: study protocol for a multicentre randomised placebo-controlled trial BBQ study

INTRODUCTION

Recurrent miscarriage (RM), defined by three or more consecutive losses during the first trimester of pregnancy, affects 1%-2% of fertile couples. Standard investigations fail to reveal any apparent cause in ~50% of couples. However, on the basis of animal models and clinical studies, several hypotheses have been put forward concerning underlying mechanisms of RM: altered ovarian reserve, progesterone defect, thrombotic and/or endothelial dysfunction and immunological disturbances. Nonetheless, no study has yet reached conclusive beneficial clinical evidence for a potential treatment in unexplained RM. Hydroxychloroquine (HCQ) is a molecule with extensive safety data during pregnancy. The pharmacological properties of HCQ (eg, antithrombotic, vascular protective, immunomodulatory, improved glucose tolerance, lipidlowering and anti-infectious) could be effective against some mechanisms of unexplained RM. Furthermore, eventhough clinical benefit of HCQ is suggested in prevention of thrombotic and late obstetric events in antiphospholipid (APL) syndrome, there are no data suggesting the benefit of HCQ in RM in the presence of APL antibodies.

METHODS AND ANALYSIS

Taken all together and given the low cost of HCQ, the aim of this multicentre, randomised, placebo-controlled, double-blind study is to investigate whether HCQ would improve the live birth rate in women with RM, irrespective of maternal thrombophilic status: (1) no known thrombophilia, (2) inherited thrombophilia or (3) APL antibodies. The primary end point is a live and viable birth. After confirming eligibility and obtaining consent, 300 non-pregnant women will be randomised into two parallel groups for a daily oral treatment (HCQ 400 mg or placebo), initiated before conception and stopped at 10 weeks' gestation. If pregnancy does not occur after 1 year, the treatment will be stopped.

ETHICS AND DISSEMINATION

Agreement from the French National Public Health and Drug Security Agency (160765A-22) and ethical approval from the Committee for the Protection of Persons of NORD-OUEST I (2016-001330-97) have been obtained.

TRIAL REGISTRATION NUMBERS

NCT0316513; Pre-results.

Effect of multiple thrombophilic gene mutations on uterine artery blood flow in nonpregnant recurrent pregnancy loss patients: are we searching enough?

Objective: To investigate whether multiple thrombophilic mutations had a significant effect on uterine artery blood flow of nonpregnant recurrent pregnancy loss (RPL) patients.Materials and methods: Among 71 RPL patients, FV Leiden (FV), prothrombin G20210A (PTGM) and MTHFR mutations, deficiency of protein S, protein C and antithrombin III (AT3), association of Val34Leu polymorphism of the FXIII (FXIII), 4G/5G polymorphism of plasminogen activator inhibitor (PAI), -455-G/A polymorphism of β-fibrinogen (fibrinogen), and HPA-1 a/b L33P polymorphism of GPIIIa (GPIIIa) genes were investigated. Doppler flow measurements of RPL patients and healthy controls were performed at mid-luteal phase.Results: Twenty-two patients who had no thrombophilic gene mutations were grouped as unexplained RPL. Also, while 25 patients had multiple mutations, 24 patients had single mutation. In the multiple mutation RPL group, the most frequent mutations were PAI (22%), MTHFR C677T (20%), MTHFR A1298C (19%), and fibrinogen (11%). Only in the multiple mutation RPL group, mean PI and dominant PI values were significantly higher than the control group.Conclusions: Our data showed negative effects of multiple thrombophilic gene mutations on uterine artery blood flow and clarified the different effects of single and multiple thrombophilic factors on uterine artery vasculature. It is concluded that investigating more thrombophilic mutations could ameliorate prognostic factors of RPL and interactions to improve uterine artery blood flow could bring benefit to obstetric outcome.

ART implantation failure and miscarriage in patients with elevated intracellular cytokine ratios: response to immune support therapy

Background

The origins of adverse reproductive outcome can be multifactorial, but the contribution of the maternal immune system is considered debatable. Elevated intracellular cytokine ratios have been proposed, although not universally supported, as a marker for immunological dysfunction in implantation and early pregnancy. Poor patient selection or inadequate treatment or testing may be confounding factors. Specific immunomodulation, in carefully selected sub-populations of ART patients with poor reproductive history, despite transfer of good quality blastocysts, may potentially improve clinical outcomes.

Methods

Intracellular cytokine ratios (CKR) were prospectively assessed in 337 patients presenting with a history of implantation failure and/or pregnancy loss, prior to further treatment, and were found to be elevated in 150 (44.5%). Of this group, 134 agreed to initiate a standardised immunotherapy regime (nutraceuticals, prednisolone & intralipids) to evaluate the efficacy of this proposed therapy. Of the intervention population, a small cohort (n = 70) delayed commencing ART for ~ 10 weeks to assess if extended pre-treatment nutraceutical supplementation could normalise CKRs prior to starting ART, and if this conferred additional benefit.

Results

Baseline assessment in the intervention population (n = 134) identified 160 miscarriages from 180 total pregnancies (89% miscarriage rate, MR), conceived both spontaneously and by assisted reproduction. Post-treatment analysis of subsequent ART cycles revealed a significant improvement in both implantation (OR 3.0, 2.0-4.5) and miscarriage rates (41/97, 42.2% MR, P < 0.001). Interestingly, pre-treatment normalisation of CKRs appeared to impart marginal extra benefit prior to subsequent fertility treatment with immunotherapy.

Conclusions

Following immunomodulation, significant improvements in both implantation rate and miscarriage rate were seen in this poor prognosis population. This suggests a possible role for both detailed immuno-evaluation of patients with poor reproductive history with good embryo quality, and application of personalised immunotherapy regimes alongside ART in selected cases. Future randomised controlled trials are needed to definitively evaluate this potentially promising therapeutic approach.

History of spontaneous miscarriage and the risk of diabetes mellitus among middle-aged and older Chinese women

AIMS

Epidemiological studies of the long-term maternal health outcomes of spontaneous miscarriages have been sparse and inconsistent. The objective of our study is to examine the association between spontaneous miscarriages and diabetes among middle-aged and older Chinese women.

METHODS

A total of 19,539 women from the Dongfeng-Tongji cohort study who completed a questionnaire and had medical examinations performed on were included in the analysis. History of spontaneous miscarriage was obtained by self-reporting in the first follow-up questionnaire interview. The presence of diabetes was determined by a fasting plasma glucose level, self-reported physician diagnosis and use of antidiabetic medication. A series of multivariate logistic regression models were used to calculate the odds ratios and 95% CI across spontaneous miscarriage categories (0, 1, 2, ≥ 3) after adjustment for potential confounding factors.

RESULTS

The prevalence rate of diabetes was 18.8% among the participants. In the fully adjusted logistic regression model, women who had 1, 2 or ≥ 3 spontaneous miscarriages had 0.86 times (95% CI 0.68, 1.08), 1.30 times (95% CI 0.82, 2.04) and 2.11 times (95% CI 1.08, 4.11) higher risk of diabetes, respectively, compared with women who had no history of spontaneous miscarriage.

CONCLUSIONS

There is an increased risk of diabetes among women with a history of a higher number of spontaneous miscarriages. History of multiple spontaneous miscarriages should be taken into consideration when assessing the risk of diabetes.

Moderate Exercise Attenuates Lipopolysaccharide-Induced Inflammation and Associated Maternal and Fetal Morbidities in Pregnant Rats

Fetal growth restriction (FGR) and coagulopathies are often associated with aberrant maternal inflammation. Moderate-intensity exercise during pregnancy has been shown to increase utero-placental blood flow and to enhance fetal nutrition as well as fetal and placental growth. Furthermore, exercise is known to reduce inflammation. To evaluate the effect of moderate-intensity exercise on inflammation associated with the development of maternal coagulopathies and FGR, Wistar rats were subjected to an exercise regime before and during pregnancy. To model inflammation-induced FGR, pregnant rats were administered daily intraperitoneal injections of E. coli lipopolysaccharide (LPS) on gestational days (GD) 13.5–16.5 and sacrificed at GD 17.5. Control rats were injected with saline. Maternal hemostasis was assessed by thromboelastography. Moderate-intensity exercise prevented LPS-mediated increases in white blood cell counts measured on GD 17.5 and improved maternal hemostasis profiles. Importantly, our data reveal that exercise prevented LPS-induced FGR. Moderate-intensity exercise initiated before and maintained during pregnancy may decrease the severity of maternal and perinatal complications associated with abnormal maternal inflammation.

Relationship between mean platelet volume and recurrent miscarriage: a preliminary study

INTRODUCTION

The aim of the study was to examine the relationship between mean platelet volume (MPV) and recurrent miscarriage in order to illuminate the etiopathogenesis of recurrent miscarriage.

MATERIAL AND METHODS

We retrospectively investigated the data of 120 patients with unexplained recurrent miscarriage (group 1), and compared them with the data of 120 match-paired patients in the control group (group 2). The definition of recurrent miscarriage was accepted as two or more failed clinical pregnancies which were documented by ultrasonography or histopathologic examination. All patients in the recurrent miscarriage group were evaluated with diagnostic tests for the etiology of recurrent miscarriage. Total blood count parameters, including hemoglobin, mean corpuscular volume, red cell distribution width, white blood cells, platelets, and mean platelet volume, were compared.

RESULTS

The average patient age at the time of examination was 29.07 ±2.81 years in group I and 28.53 ±3.5 years in group II (p > 0.05). Mean body mass index (BMI) was similar between group 1 and group 2, 22.54 ±3.17 and 22.99 ±2.38, respectively (p > 0.05). Mean hemoglobin, mean corpuscular volume, red cell distribution width, and white blood cell and platelet levels were similar in both groups (p > 0.05). Mean platelet volume levels were significantly higher in group I (9.45 ±1.09 fl) than in group II (7.63 ±0.52 fl) (p = 0.001).

CONCLUSIONS

Higher MPV values in the study group suggest and support the importance of thromboembolic events in the etiology of recurrent miscarriage.

Prothrombotic state of patients with unexplained recurrent spontaneous abortion

OBJECTIVE

To determine the effect of aspirin and low-molecular-weight heparin (LMWH) for women affected by recurrent spontaneous abortion (RSA).

METHODS

The present prospective observational study included women with RSA (≥ 2 previous spontaneous abortions) and those without a history of RSA attending Ren Ji Hospital, Shanghai, China, between March 2011 and March 2014. D-dimer levels, auto-antibodies, and platelet aggregation in response to arachidonic acid (AA) and adenosine diphosphate (ADP) were monitored before pregnancy. Women with unexplained RSA and increased platelet aggregation received low-dose aspirin, and those with elevated D-dimer levels (> 0.75 μg/mL) received LMWH. Platelet aggregation in response to AA and ADP, and D-dimer levels were monitored during pregnancy.

RESULTS

Among 517 participants with RSA, 325 had unexplained RSA. Compared with 63 control patients, those with unexplained RSA and two, three, four, or at least five previous spontaneous abortions had increased platelet aggregation in response to AA (P < 0.05 for all comparisons) but not to ADP. Among 37 women with unexplained RSA who became pregnant, aspirin reduced platelet aggregation in response to AA (P < 0.001). LMWH reduced D-dimer levels during pregnancy (P < 0.001). Among 37 women with unexplained RSA who became pregnant and completed the study, 33 (89.2%) had a live birth.

CONCLUSION

Aspirin and LMWH maintained a lower thrombotic state and led to a high live birth rate among patients with unexplained RSA.

Enoxaparin for prevention of unexplained recurrent miscarriage: a multicenter randomized double-blind placebo-controlled trial

It is common practice in many centers to offer antithrombotic medications to women with unexplained recurrent miscarriage, in the presence or absence of inherited thrombophilia. Although no benefit of aspirin vs placebo has been clearly demonstrated, a double-blind placebo-controlled trial on the effect of low-molecular-weight heparin is lacking. We enrolled 258 pregnant women with a history of unexplained recurrent miscarriage (≥2 consecutive miscarriages before 15 weeks' gestation) and a negative thrombophilia workup. They were randomly assigned to receive one daily subcutaneous injection of enoxaparin 40 mg or placebo until 35 weeks' gestation. We included 256 women (mean age 32 years, ≥3 miscarriages: 72%; mean gestational age 39 days of amenorrhea) in the intention-to-treat analysis; 66.6% of 138 who received enoxaparin had a live birth vs 72.9% of 118 who received placebo. The absolute difference was -6% (95% CI, -17.1 to 5.1), excluding a 10% increase in the rate of live-birth on enoxaparin (P = .34). In this first randomized, double-blind, placebo-controlled trial, enoxaparin (40 mg once daily) did not improve the chance of a live birth in nonthrombophilic women with unexplained recurrent miscarriage. This trial is registered at www.ClinicalTrials.gov as #NCT00740545 and the French National Health and Drug Safety Agency (EudraCT #2006-003350-18).

Evidence-based management of recurrent miscarriages

Recurrent miscarriages are postimplantation failures in natural conception; they are also termed as habitual abortions or recurrent pregnancy losses. Recurrent pregnancy loss is disheartening to the couple and to the treating clinician. There has been a wide range of research from aetiology to management of recurrent pregnancy loss. It is one of the most debated topic among clinicians and academics. The ideal management is unanswered. This review is aimed to produce an evidence-based guidance on clinical management of recurrent miscarriage. The review is structured to be clinically relevant. We have searched electronic databases (PubMed and Embase) using different key words. We have combined the searches and arranged them with the hierarchy of evidences. We have critically appraised the evidence to produce a concise answer for clinical practice. We have graded the evidence from level I to V on which these recommendations are based.

Risk for early pregnancy loss by factor XIII Val34Leu: the impact of fibrinogen concentration

BACKGROUND

We have already described a significantly elevated overall risk for recurrent pregnancy loss (RPL) in women carrying the coagulation factor XIII (FXIII) Val34Leu and/or the plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphism assuming that these polymorphisms contribute synergistically to RPL because of impaired hypofibrinolysis. Recent studies on FXIII indicate that the impact of the FXIII 34Leu genotype on fibrin structure and fibrinolysis is affected by fibrinogen concentration. Therefore, we reinvestigated the association between fibrinogen concentrations and FXIII Val34Leu with early RPL.

MATERIALS AND METHODS

In this case-control study, we enrolled 49 women with a history of two consecutive or three to six nonconsecutive pregnancy losses between the 8th and 12th week of gestation and 48 healthy controls. The risk for RPL in carriers of FXIII 34Leu at fibrinogen levels above or below the median and first tertile of controls was evaluated.

RESULTS

In carriers of the 34Leu allele, fibrinogen levels below the median (i.e., ≤ 300 mg/dl) and the first tertile (i.e., ≤ 284 mg/dl) of controls were associated with an increased risk for RPL [(2.9 (1.1-7.7), 3.9(1.0-15.0)].

CONCLUSIONS

The FXIII Val34Leu polymorphism may be associated with the development of early RPL in association with fibrinogen concentrations. At fibrinogen levels in the low normal range, FXIII 34Leu may modify fibrin structure toward an increased resistance to fibrinolysis.

Could platelet distribution width be a predictive marker for unexplained recurrent miscarriage?

PURPOSE

The aim of our study was to evaluate the platelet function in unexplained recurrent miscarriage and to investigate whether any hematologic changes detectable by simple complete blood count have a diagnostic value for the prediction of unexplained recurrent miscarriage.

METHODS

A prospective study based on the comparison of 74 patients with unexplained recurrent first-trimester pregnancy loss with 208 control subjects matched for age. The two groups were compared in terms of platelet indices.

RESULTS

There was a significant difference in platelet distribution width in patients with unexplained recurrent miscarriage compared to healthy control subjects. Platelet distribution width values in the patient group were statistically higher (P < 0.001) than the control group.

CONCLUSION

Our study provides an evidence that platelet distribution width gradually increases in women with recurrent miscarriage compared to control group. Patients with unexplained recurrent miscarriage have significantly increased platelet aggregation. This data may provide an empirical rationale for the use of anticoagulants in the management of this clinical condition.

Thromboembolism risk following recurrent miscarriage

Normal pregnancy is associated with extensive changes in hemostasis such that the procoagulant effect becomes dominant. The evolutionary advantage of this hypercoagulability may be to counteract the inherent instability associated with hemochorial placentation, which is unique to human beings. However, overall, there is a four- to 10-fold increased thrombotic risk throughout gestation and the postpartum period. Certain inherited or acquired thrombophilic factors may predispose to arterial and/or venous thrombosis and have a possible association with pregnancy complications, including recurrent miscarriage (RM), which affects up to 5% of couples with childbearing desire. A subgroup of women with RM has been demonstrated to be in a prothombotic state before and after pregnancy. The long-term health implications of this hypercoagulability may imply an increased risk of ischemic heart disease. Moreover, the presence of antiphospholipid antibodies rather than thrombophilic genetic defects (i.e., factor V Leiden or prothrombin G202010A mutation) in patients with RM is a determinant of thrombotic events later in life, especially among those patients having also cardiovascular risk factors. This article highlights the thromboembolic risk in nonpregnant RM patients in different thrombophilic settings and the need for thromboprophylaxis among these patients.

Biomechanics of haemostasis and thrombosis in health and disease: from the macro- to molecular scale

Although the processes of haemostasis and thrombosis have been studied extensively in the past several decades, much of the effort has been spent characterizing the biological and biochemical aspects of clotting. More recently, researchers have discovered that the function and physiology of blood cells and plasma proteins relevant in haematologic processes are mechanically, as well as biologically, regulated. This is not entirely surprising considering the extremely dynamic fluidic environment that these blood components exist in. Other cells in the body such as fibroblasts and endothelial cells have been found to biologically respond to their physical and mechanical environments, affecting aspects of cellular physiology as diverse as cytoskeletal architecture to gene expression to alterations of vital signalling pathways. In the circulation, blood cells and plasma proteins are constantly exposed to forces while they, in turn, also exert forces to regulate clot formation. These mechanical factors lead to biochemical and biomechanical changes on the macro- to molecular scale. Likewise, biochemical and biomechanical alterations in the microenvironment can ultimately impact the mechanical regulation of clot formation. The ways in which these factors all balance each other can be the difference between haemostasis and thrombosis. Here, we review how the biomechanics of blood cells intimately interact with the cellular and molecular biology to regulate haemostasis and thrombosis in the context of health and disease from the macro- to molecular scale. We will also show how these biomechanical forces in the context of haemostasis and thrombosis have been replicated or measured in vitro.

Nitroglycerin prevents coagulopathies and foetal death associated with abnormal maternal inflammation in rats

Inflammation-associated foetal loss is often linked to maternal coagulopathies. Here, we characterised the role of maternal inflammation in the development of various systemic maternal coagulopathies and foetal death during mid-to-late gestation in rats. Since nitric oxide (NO) functions as an inhibitor of platelet aggregation and anti-oxidant, we also tested whether the NO mimetic nitroglycerin (glyceryl trinitrate, GTN) prevents inflammation-associated coagulopathies and foetal death. To induce chronic inflammation, pregnant Wistar rats were injected with low-doses of lipopolysaccharide (LPS; 10-40 μg/kg) on gestational days (GD) 13.5-16.5. To determine whether the effects of inflammation are mediated by tumour necrosis factor-α (TNF-α), the TNF-α inhibitor etanercept was injected on GD 13.5 and 15.5. Controls consisted of rats injected with saline. GTN was administered to LPS-treated rats via daily application of a transdermal patch on GD 12.5-16.5. Using thromboelastography (TEG), various coagulation parameters were assessed on GD 17.5; foetal viability was determined morphologically. Reference coagulation parameters were established based on TEG results obtained from control animals. LPS-treated rats exhibited distinct systemic coagulopathies: hypercoagulability, hypocoagulability, hyperfibrinolysis, and disseminated intravascular coagulation (DIC) stages I and III. A specific foetal death coagulation phenotype was observed, implicating TEG as a potential tool to identify inflammation-induced haemostatic alterations associated with pregnancy loss. Treatment with etanercept reduced the incidence of coagulopathy by 47%, while continuous delivery of GTN prevented foetal death and the inflammation-induced coagulopathies. These findings provide a rationale for investigating the use of GTN in the prevention of maternal coagulopathies and inflammation-mediated foetal death.

Hemotransfusion in Combat Trauma

The collaboration of blood transfusion service in the management of severely combat-injured individuals has proved to be an essential factor for the successful treatment of these patients. While the operating and anesthesiology teams are engaged in maintaining the vital signs and controlling blood loss of the injured, the transfusion service representatives follow the information on the amount of blood products given and the latest laboratory tests, as well as provide consultations regarding further blood component requirements on the basis of data obtained. A major effort of the treating team should be aimed at diagnosis and correction of coagulopathy, acidosis, and hypothermia. For the massively bleeding combat trauma injured, which can amount to as high as 8% of all trauma patients, a generous use of plasma at a one-to-one ratio with packed cells, along with the early addition of platelets and cryoprecipitates, should be considered. Early point-of-care thromboelastography is helpful for identification of coagulopathies. The use of a preset massive transfusion protocol is beneficial; however, it should be tailored according to the patient’s actual needs, depending on the type of injury and the individual’s general condition.

Platelet reactivity and pregnancy loss

OBJECTIVE

We sought to critically evaluate platelet function in recurrent miscarriage (RM).

STUDY DESIGN

We conducted a prospective study comparing 30 patients with unexplained recurrent first-trimester pregnancy loss with 30 control subjects matched for age and serum progesterone level. Platelet function was determined using a modified assay of light transmission aggregometry with multiple agonists at different concentrations. Dose-response curves were created and half-maximal effective concentration values were calculated.

RESULTS

At test completion the half-maximal effective concentration values for arachidonic acid in the patients with RM were significantly less than in the control subjects (0.153 vs 0.230; P = .0099). The dose-response curves were tightly matched for the other agonists.

CONCLUSION

This novel measurement of platelet function has demonstrated that patients with unexplained RM have significantly increased platelet aggregation in response to arachidonic acid. The enhanced response to this agonist provides an empirical rationale for the use of aspirin in management of this clinical condition.

Recurrent miscarriage: current concepts in diagnosis and treatment

Although recurrent miscarriage (RM) affects only 1-3% of couples, it has a major influence on the wellbeing and psychosocial status of patients. Therefore, research into improved diagnosis and development of new treatment strategies is essential. In this review, we summarize current concepts on diagnosis and treatment in RM, drawing upon research reports and international guidelines to provide insights into the pathophysiology of pregnancy disrupted by repeated miscarriage. Anatomical malformations, infectious diseases, endocrine disorders, autoimmune defects as well as acquired and inherited thrombophilia are established risk factors in RM. In addition, our recent findings indicate an impact on miscarriage incidence of glycoproteins such as glycodelin, and nuclear hormone receptors such as the peroxisome proliferator-activated receptors (PPARs). Significantly reduced glycodelin expression is associated with miscarriage, whereas up-regulation of PPARs appears to compensate for either the activated immune response or the disturbed cytotrophoblast differentiation in RM patients. There is also evidence that circulating placental microparticles are increased in a subgroup of RM patients, indicating an acquired procoagulant state even outside pregnancy. Treatment strategies like aspirin and low molecular weight heparin (LMWH) are standard medications in RM, although only a few placebo-controlled trials have proven their benefit in respect to live birth rate. There is emerging evidence that new treatment options, including drugs like TNFalpha inhibitors and granulocyte colony-stimulating factor (G-CSF) might be beneficial in some cases of RM. However, larger clinical trials must be completed to further prove or disprove benefits of these drugs in the treatment of RM patients.

Rapid thrombelastography (r-TEG) identifies hypercoagulability and predicts thromboembolic events in surgical patients

BACKGROUND

Despite routine prophylaxis, thromboembolic events (TEs) in surgical patients remain a substantial problem. Furthermore, the timing and incidence of hypercoagulability, which predisposes to these events is unknown, with institutional screening programs serving primarily to establish a diagnosis after an event has occurred. Emerging evidence suggests that point of care (POC) rapid thrombelastography (r-TEG) provides a real-time analysis of comprehensive thrombostatic function, which represents an analysis of both enzymatic and platelet components of thrombus formation. We hypothesized that r-TEG can be used as a screening tool to identify hypercoagulable states in surgical patients and would predict subsequent thromboembolic events.

METHODS

Rapid thrombelastography r-TEG analyses were performed on 152 critically ill patients in the surgical intensive care unit (ICU) during 7 months. Hypercoagulability was defined as clot strength (G)>12.4 dynes/cm(2). Variables of interest for identifying hypercoagulability and thromboembolic events included sex, age, operating hospital service, specific injury patterns, injury severity score (ISS), transfusion within first 24 h, ICU duration of stay, ventilator days, hospital admission days, and thromboprophylaxis. Comparisons between the hypercoagulable and normal groups or between the groups with and without thromboembolic events were performed using Chi-square tests or the Fisher exact test for categorical variables and independent sample t tests or Wilcoxon rank sum tests for continuous variables. Multivariate logistic regression analysis (LR) was performed to identify independent predictors of thromboembolic events. A receiver operating characteristic curve was used to measure the performance of G for predicting the occurrence of a TE event. All tests were 2-sided with significance of P < .05.

RESULTS

In all, 86 patients (67%) were hypercoagulable by r-TEG. More than 85% of patients in the hypercoagulable group and 79% in the normal group received thromboprophylaxis during the study period. The differences between hypercoagulable and normal groups by bivariate analysis included high-risk injuries (52% vs 35%; P = .03), spinal cord injury (27% vs 12%; P = .03), median ICU duration of stay (13 vs 7 days; P < .001), median ventilator days (6 vs 2; P < .001), and median hospital duration of stay (20 vs 13 days; P < .001). A total of 16 patients (19%) of the hypercoagulable group suffered a thromboembolic event, and 10 hypercoagulable patients (12%) had thromboembolic events predicted by prior r-TEG hypercoagulability. No patients with normal coagulability by r-TEG had an event (P < .001). LR analysis showed that the strongest predictor of TE after controlling for the presence of thromboprophylaxis was elevated G value (odds ratio: 1.25, 95% confidence interval [CI]: 1.12-1.39). For every 1 dyne/cm(2) increase in G, the odds of a TE increased by 25%.

CONCLUSION

These results indicate that the presence of hypercoagulability identified by r-TEG is predictive of thromboembolic events in surgical patients. Subsequent study is necessary to define optimal prophylactic treatment strategies for patients with r-TEG proven hypercoagulability.

Haemostatic changes in the puerperium '6 weeks postpartum' (HIP Study) - implication for maternal thromboembolism

OBJECTIVE

We aim to measure the thrombotic changes during the postnatal period up to 6 weeks after delivery and assess the extent of the risk period.

DESIGN

Prospective observational study.

SETTING

Queen Elizabeth II, an acute District General Hospital, Hertfordshire.

POPULATION

Women booked at the antenatal clinic and prepared to deliver at the hospital.

METHODS

We assessed the haemoglobin, platelet count and function, fibrinogen, prothrombin time, activated partial thromboplastin time, protein C, S and antithrombin level and as well as rotational thromboelastometry (ROTEM) from predelivery till 6 weeks postpartum.

RESULTS

A total 50 women were recruited of which four dropped out. Results compared against the finding at 6 weeks after delivery. Platelet was significantly elevated on day 19 compared to day 42 (P < 0.001). Fibrinogen was elevated from predelivery till day 15 after delivery (P < 0.01). Prothrombin time (PT) was low till day 15 (P < 0.05) and activated partial thromboplastin time (APTT) was significantly lower till day 3 after delivery (P < 0.001). ROTEM revealed low clotting time (CT) at predelivery and continued to be low till day 7. Clot formation time (CFT) significantly low till day 25 (P < 0.05). Maximum clot firmness, alpha angle and amplitude at 20 minutes were raised till day 19 (P < 0.001, P < 0.01 and P < 0.001 respectively). While, comparing vaginal delivery against caesarean section there were nonsignificant increase in thrombotic parameters in caesarean section.

CONCLUSION

Coagulation screens as well as thomboelastometry suggest a persistent hypercoagulation during the first 3 weeks after delivery.

Microparticles and exosomes: impact on normal and complicated pregnancy

Eukaryotic cells release vesicles into their environment by membrane shedding (ectosomes or microparticles) and secretion (exosomes). Microparticles and exosomes occur commonly in vitro and in vivo. The occurrence, composition and function(s) of these vesicles change during disease (progression). During the last decade, the scientific and clinical interest increased tremendously. Evidence is accumulating that microparticles and exosomes may be of pathophysiological relevance in autoimmune, cardiovascular and thromboembolic diseases, as well as inflammatory and infectious disorders. In this review, we will summarize the discovery, biology, structure and function of microparticles and exosomes, and discuss their (patho-) physiological role during normal and complicated pregnancy.

Frequency of Uterine Malformations Among Women in a Restricted Gene Pool Community

This random, retrospective cross-sectional study was performed to determine the frequency of uterine malformation in restricted gene pool communities. During 2003—2006, 800 women from the community of LaCrete in northern Alberta, Canada (known restricted gene pool for over 500 years), participated. Of the participants, 156 (19.5% of the study population) showed some form of structural uterine malformation. This is 5.5 times higher than what is reported in the general population. All 156 subjects were further investigated with magnetic resonance imaging, 3D sonography, hysterosalpingiography, hysteroscopy, and laparoscopy. These tests revealed that 30 of these women had no previous pregnancies or live births, 40 had one or more previous pregnancies and live births and more than two miscarriages, and 55 had recurrent miscarriages. This study has provided new insights into the increasing number of uterine malformations in the LaCrete population. The significantly higher prevalence of uterine malformations in a restricted gene pool community compared to the reported prevalence in the general population might indicate a direct link between a lack of genetic diversity and the development of uterine malformations in women.

The effect of colloid and crystalloid preloading on thromboelastography prior to Cesarean delivery

PURPOSE

Fluid preloading with colloids reduces hypotension after spinal anesthesia for Cesarean delivery more effectively than crystalloids. However, the effects of fluid preloading regimens on coagulation in pregnant patients remain unresolved. The aim of this study was to compare the effects on coagulation of fluid preloading with 6% hydroxyethyl starch (HES) and lactated Ringer's (LR) solution using thromboelastography (TEG) with kaolin-activated whole blood in healthy pregnant patients prior to spinal anesthesia for Cesarean delivery.

METHODS

After obtaining Ethics committee approval, 30 parturients were prospectively randomized prior to spinal anesthesia for elective Cesarean delivery to receive fluid preloading with either 1500 mL LR or 500 mL 6% HES over 30 min. Thromboelastography was performed immediately prior to and after fluid preloading. Standard TEG parameters were analyzed in terms of r time (min), k time (min), alpha angle (degrees) and maximum amplitude (mm).

RESULTS

Group HES had statistically significant longer reaction times (r) and clot formation times (k) after fluid loading compared to baseline values (P < 0.05 respectively), although these post-fluid loading TEG parameters remained within a normal reference range. No significant differences in TEG values were seen after preloading within the LR group.

CONCLUSION

Fluid preloading with 500 mL 6% HES in healthy parturients produced mild coagulation effects, as measured with TEG, prior to spinal anesthesia for Cesarean delivery. No significant effects on coagulation with TEG were observed following preloading with 1500 mL LR.

Recurrent miscarriage

Many human conceptions are genetically abnormal and end in miscarriage, which is the commonest complication of pregnancy. Recurrent miscarriage, the loss of three or more consecutive pregnancies, affects 1% of couples trying to conceive. It is associated with psychological morbidity, and has often proven to be frustrating for both patient and clinician. A third of women attending specialist clinics are clinically depressed, and one in five have levels of anxiety that are similar to those in psychiatric outpatient populations. Many conventional beliefs about the cause and treatment of women with recurrent miscarriage have not withstood scrutiny, but progress has been made. Research has emphasised the importance of recurrent miscarriage in the range of reproductive failure linking subfertility and late pregnancy complications and has allowed us to reject practice based on anecdotal evidence in favour of evidence-based management.