Venous thromboembolism, thrombophilia, antithrombotic therapy, and pregnancy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

Pregnancy-specific glycoproteins bind integrin αIIbβ3 and inhibit the platelet-fibrinogen interaction

Pregnancy-specific glycoproteins (PSGs) are immunoglobulin superfamily members encoded by multigene families in rodents and primates. In human pregnancy, PSGs are secreted by the syncytiotrophoblast, a fetal tissue, and reach a concentration of up to 400 ug/ml in the maternal bloodstream at term. Human and mouse PSGs induce release of anti-inflammatory cytokines such as IL-10 and TGFβ1 from monocytes, macrophages, and other cell types, suggesting an immunoregulatory function. RGD tri-peptide motifs in the majority of human PSGs suggest that they may function like snake venom disintegrins, which bind integrins and inhibit interactions with ligands. We noted that human PSG1 has a KGD, rather than an RGD motif. The presence of a KGD in barbourin, a platelet integrin αIIbβ3 antagonist found in snake venom, suggested that PSG1 may be a selective αIIbβ3 ligand. Here we show that human PSG1 binds αIIbβ3 and inhibits the platelet – fibrinogen interaction. Unexpectedly, however, the KGD is not critical as multiple PSG1 domains independently bind and inhibit αIIbβ3 function. Human PSG9 and mouse Psg23 are also inhibitory suggesting conservation of this function across primate and rodent PSG families. Our results suggest that in species with haemochorial placentation, in which maternal blood is in direct contact with fetal trophoblast, the high expression level of PSGs reflects a requirement to antagonise abundant (3 mg/ml) fibrinogen in the maternal circulation, which may be necessary to prevent platelet aggregation and thrombosis in the prothrombotic maternal environment of pregnancy.

New directions in the diagnosis and treatment of pulmonary embolism in pregnancy

The diagnosis and management of pulmonary embolism in pregnancy is difficult, because diagnostic procedures and the use of anticoagulants potentially can expose mother and fetus to adverse effects. This article reviews evidence for current best practice and emerging novel techniques for the diagnosis of pulmonary embolism in pregnancy and includes clinical prediction models, biomarkers, and diagnostic imaging that may offer improvement in the diagnosis and investigation of pulmonary embolism in pregnancy in the future. The usefulness of new anticoagulant agents (fondaparinux, rivaroxaban, and dabigatran) in managing pulmonary embolism in future pregnancies is also explored.

Sulfated pentagalloylglucoside is a potent, allosteric, and selective inhibitor of factor XIa

Inhibition of factor XIa (FXIa) is a novel paradigm for developing anticoagulants without major bleeding consequences. We present the discovery of sulfated pentagalloylglucoside (6) as a highly selective inhibitor of human FXIa. Biochemical screening of a focused library led to the identification of 6, a sulfated aromatic mimetic of heparin. Inhibitor 6 displayed a potency of 551 nM against FXIa, which was at least 200-fold more selective than other relevant enzymes. It also prevented activation of factor IX and prolonged human plasma and whole blood clotting. Inhibitor 6 reduced V(MAX) of FXIa hydrolysis of chromogenic substrate without affecting the K(M), suggesting an allosteric mechanism. Competitive studies showed that 6 bound in the heparin-binding site of FXIa. No allosteric small molecule has been discovered to date that exhibits equivalent potency against FXIa. Inhibitor 6 is expected to open up a major route to allosteric FXIa anticoagulants with clinical relevance.

GRADE guidelines: 14. Going from evidence to recommendations: the significance and presentation of recommendations

This article describes the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to classifying the direction and strength of recommendations. The strength of a recommendation, separated into strong and weak, is defined as the extent to which one can be confident that the desirable effects of an intervention outweigh its undesirable effects. Alternative terms for a weak recommendation include conditional, discretionary, or qualified. The strength of a recommendation has specific implications for patients, the public, clinicians, and policy makers. Occasionally, guideline developers may choose to make "only-in-research" recommendations. Although panels may choose not to make recommendations, this choice leaves those looking for answers from guidelines without the guidance they are seeking. GRADE therefore encourages panels to, wherever possible, offer recommendations.

Retrievable vena cava filters: a clinical review

Venous thromboembolism (VTE), including deep vein thrombosis and pulmonary embolism (PE), is a major cause of morbidity and mortality. Parenteral anticoagulant treatment with full-dose unfractioned heparin, low-molecular-weight-heparin, or fondaparinux, followed by oral treatment with the vitamin K antagonists, is recommended for the majority of patients. However, in the presence of contraindications to anticoagulant treatment, bleeding complications during antithrombotic treatment, or VTE recurrences despite optimal anticoagulation, interruption of the inferior vena cava with a filter is a potential option aimed to prevent life-threatening PE. Currently, the vast majority of filters implanted worldwide are of the permanent type, but their use is associated with a number of long term complications. Non-permanent filters represent an important alternative, and in particular retrievable filters are an attractive option because they may be either left in place permanently or safely retrieved after a quite long period when they become unnecessary. In this review, we summarize the currently available literature regarding retrievable vena cava filters and we discuss current evidences on their efficacy and safety. Moreover, the appropriate indications for their use in daily clinical practice are reviewed.

Heparin-induced skin lesions

Heparins are widely used for prophylaxis and treatment of thromboembolic diseases. Besides bleeding complications, heparin-induced skin lesions are the most frequent unwanted adverse effects of subcutaneous heparin treatment. Evidence suggests that these lesions are more common than previously thought. Lesions are most frequently due to either allergic reactions or to possibly life-threatening heparin-induced thrombocytopenia. Early recognition and adequate treatment are highly important, because although both complications initially show a similar clinical picture, their treatment should be fundamentally different. Furthermore, risk factors associated with the patient, drug, and treatment regimen have been identified. We review the clinical range of heparin-induced skin lesions, emphasise evidence and controversies in epidemiology, diagnosis, and differential diagnosis, and discuss the management of patients with these skin lesions.

Treatment of refractory obstetric antiphospholipid syndrome: the state of the art and new trends in the therapeutic management

Objective

To date, there are no reliable data regarding the actual treatment received by women with refractory obstetric antiphospholipid syndrome (OAPS). The aim of this study was to assess current clinical evidence and new trends in the treatment of refractory OAPS.

Methods

A non-systematic but comprehensive literature search using relevant keywords was made to identify relevant articles published in English from different computerized databases: PubMed (Medline), Google Scholar electronic database search and The Cochrane Library, from January 2000 to March 2012. Studies on the treatment of poor obstetric outcomes in women with OAPS were included. Prospective randomized clinical trials, cohort studies, reviews, systematic reviews and meta-analysis were retrieved.

Results

A total of 130 articles were finally selected for this review, including 17 randomized clinical trials and four meta-analyses. The majority of articles were non-randomized original papers and basic and clinical reviews.

Conclusion

Up to 20% of women with OAPS do not receive the currently recommended therapeutic regimen. Unfortunately, well-designed studies regarding the usefulness of new drugs in refractory OAPS are scarce. Hydroxychloroquine and low-dose prednisolone appear to be useful when added to standard therapy. Current data do not support the use of intravenous immunoglobulins in this field. The role played by double anti-aggregant therapy, fondaparinux, vitamin D, pentoxifylline and TNF-targeted therapies should be tested in well-designed studies.

Does asymptomatic carriage of FV Leiden and FII prothrombin mutations in heterozygous configuration pose an increased risk of thrombembolic complications in the course of pregnancy, labor and puerperium?

OBJECTIVE

To evaluate the course of pregnancy and puerperium in asymptomatic carriers of FV Leiden and FII prothrombin mutation in heterozygous configuration in terms of risk of thrombembolic disease (TED) and late pregnancy complications. To evaluate whether global prophylactic LMWH administration during pregnancy benefits these women.

METHODS

We monitored the incidence of thrombembolic events and severe late pregnancy complications in 473 asymptomatic carriers of FV Leiden and FII prothrombin mutation in heterozygous configuration. In 253 women, preventive LMWH application was introduced already during pregnancy. In 220 women, the application of LMWH was commenced as late as on the delivery day. In both groups application of LMWH continued during the puerperium.

RESULTS

The incidence of TED in the whole group of carriers of thrombophylic mutations accounted for 0.19%. The incidence of severe late pregnancy complications was low - 2.5% compared with general population of pregnant women (6.4%).

CONCLUSIONS

No direct causal relationship was established between asymptomatic carriage of Leiden and prothrombin mutation in heterozygous configuration and the occurrence of severe late pregnancy complications. There was no benefit from general LMWH prophylaxis started as early as pregnancy in these women and thus we consider it unnecessary.

The development of evidence-based care recommendations to improve the safe use of anticoagulants in children

Evidence-based care recommendations and standardized protocols improve outcomes. In addition, anticoagulant management has been recognized by The Joint Commission (TJC) as an opportunity for improving patient safety. A National Patient Safety Goal requiring a standardized process for patients receiving anticoagulants was established by TJC. This requirement provided an opportunity to apply evidence-based care recommendations to the issue of safe anticoagulant use. To meet TJC requirement, the following searchable clinical question was drafted: "In children receiving anticoagulation therapy, what are the appropriate dosing, laboratory monitoring, timing, and dosing adjustments for warfarin, unfractionated heparin, and low-molecular-weight heparin to prevent coagulation-related complications?" The team used the Appraisal of Guidelines Research and Evaluation Collaboration (AGREE) instrument to evaluate the quality and relevance of identified guidelines in answering the clinical question. Best Evidence Statements (BESts) were developed for each of the medications (warfarin, low-molecular-weight heparin, and unfractionated heparin). BESts provide the format for the presentation of recommendations, discussion, and methods for point-of-care providers seeking synthesized evidence to guide care decisions. The primary goal of developing and implementing these statements was to standardize the use of anticoagulants and to prevent unsafe practices. A secondary goal was to ensure accessibility of the BESts throughout our organization, including the electronic medical record, various internal division home pages, and our organization's external website. The anticoagulant BESts developed at our organization show how an interprofessional approach to patient care results in the development of evidence-based care recommendations. The BESts were developed to standardize care associated with the use of anticoagulants and to provide dosing and monitoring parameters to ensure safe care to all patients receiving these medications. The development of evidence-based care recommendations can be accomplished with a focused interprofessional team dedicated to providing the safest possible care to patients.

Recurrent miscarriage and thrombophilia: an update

PURPOSE OF REVIEW

Acquired and inherited thrombophilia is an important research avenue in the recurrent miscarriage field. The optimum treatment for patients with recurrent miscarriage and a confirmed thrombophilia remains a contentious issue. We aim to appraise and explore the latest research in the field of thrombophilia and recurrent miscarriage in this review.

RECENT FINDINGS

Antiphospholipid syndrome (APS) is the only proven thrombophilia that is associated with adverse pregnancy outcomes. Research involving inherited thrombophilia and recurrent miscarriage is limited to small observational studies with small and heterogeneous populations. Aspirin and heparin therapy are frequently prescribed for APS, yet there is no robust evidence for the most efficacious regime. The combination of inherited hypercoagulability and environmental factors in association with recurrent miscarriage has recently been explored as an aid to identify high-risk individuals.

SUMMARY

The cause of recurrent miscarriage is multifactorial and appropriate treatment continues to be a challenge. Laboratory tests need to be standardized and well designed multicentre research trials are essential to expand on the current knowledge base with the aim to produce strong evidence-based medicine.

Successful treatment of acute lymphoblastic leukemia in a child with trisomy 21 and complex congenital heart disease with mechanical prosthetic valve

A 10-year-old girl with trisomy 21 and complex congenital heart disease presented with acute lymphoblastic leukemia. Her chemotherapy required modifications due to poor baseline cardiac status and a mechanical prosthetic heart valve that was dependent on anticoagulation. We describe our management including the use of low-molecular-weight heparin as anticoagulation for a mechanical heart valve, the safe delivery of intrathecal chemotherapy included bridging with unfractionated heparin, and the use of fluoroscopic guidance to minimize the risk of bleeding. Adjustments were made to avoid anthracyclines. The child tolerated therapy well without complications and remains relapse free five years after diagnosis.

Implications of the first cesarean: perinatal and future reproductive health and subsequent cesareans, placentation issues, uterine rupture risk, morbidity, and mortality

Rates of cesarean delivery have substantially increased worldwide during the past 30 years. Indeed, almost one-third of deliveries in the United States are cesareans. Most cesareans are safe, and major complications are uncommon. However, there is a "concealed" downside to cesarean deliveries. There are rare but life-threatening morbidities that may occur, which are often overlooked because most cesareans go well. In addition, subsequent pregnancies are fraught with an increased risk of both maternal and fetal complications. The worst of these are associated with placental problems such as previa, abruption, and accreta. The risk dramatically worsens in patients with multiple repeat cesarean deliveries. This article will summarize and highlight the implications of the rising cesarean rate on maternal and fetal morbidity and mortality.

[Antiphospholipid syndrome and pregnancy]

Antiphospholipid syndrome is characterized by arterial and venous thromboembolic events and persistent laboratory evidence of antiphospholipid antibodies. Obstetric complications such as recurrent miscarriage, early delivery, oligohydramnios, prematurity, intrauterine growth restriction, fetal distress, fetal or neonatal thrombosis, pre-eclampsia/eclampsia, and HELLP syndrome are also hallmarks of antiphospholipid syndrome. This syndrome is one of the diseases associated with the most severe thrombotic risk. Changes in the hemostatic system during normal pregnancy also result in a hypercoagulable state resulting in elevated thrombotic risk. Thromboembolic events are responsible of the vast majority of maternal and fetal deaths. Administration of appropriate thromboprophylaxis helps prevent thromboembolic complications during pregnancy in women with antiphospholipid syndrome and also give birth to healthy children. It is important to centralize the medication and management of these patients. It helps in the thoughtful care of these pregnant women encountering serious problems.

Management of antiphospholipid syndrome

The antiphospholipid syndrome (APS) is an autoimmune disorder presenting with tissue injury in various organs related to large- or small-vessel thrombosis associated with antiphospholipid and antiprotein/phospholipid complex antibodies. Although the pathophysiology, diagnosis, and clinical scenario may seem clear and straightforward, a more detailed examination reveals a more complex and uncertain picture related to the management of APS. This article reviews the current situation relating to APS therapy by evaluating the different clinical features of the syndrome ranging from thrombosis to pregnancy complications together with new strategies and pharmacological approaches.

Participation of protein Z-dependent protease inhibitor and protein Z system in the pathomechanism of thrombotic complications

Thrombotic complications of unknown etiology remain a serious diagnostic and therapeutic problem. Occurrence of the inherited polymorphisms of genes encoding proteins involved in the coagulation cascade is one of the possible causes of these complications. In recent years, protein Z (PZ) and PZ-dependent protease inhibitor (ZPI) have been added to the list of prothrombotic factors. PZ is a glycoprotein serving as a cofactor of ZPI, which is responsible for the inhibition of prothrombinase. Expression of the PZ gene is under the control of many transcriptional factors; several polymorphisms alternate the rate of gene expression. The present article describes the significance of the ZPI-PZ system in venous and arterial thrombosis, adverse pregnancy outcomes and antiphospholipid syndrome complications.

Management of pregnancy in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoantibody-mediated systemic autoimmune disease, predominantly affecting young females. Pregnancy is increasingly common in the setting of SLE, as survival and quality of life of patients improve. Although live births can be achieved in the most cases, pregnancy in patients with SLE remains a high-risk condition. Maternal and fetal mortality and morbidity are considerably increased, compared with the general population. Aberrations in pregnancy-related maternal immune adaptations are likely contributors. Active maternal disease, renal involvement, specific autoantibody subsets and advanced organ damage are predictors of poor outcome. Therapeutic options are limited during pregnancy as maternal benefit has to be weighed against fetal risk. Prevention of preterm birth and refractory pregnancy loss, as well as management of established neonatal heart block remain unmet needs. Further research should address these important issues that affect young patients with SLE and their babies.

Duration of anticoagulation after cerebral venous sinus thrombosis

Cerebral venous sinus thrombosis (CVST) often occurs in young patients and is treated with acute and then long-term oral anticoagulation. It is important to decide when to discontinue anticoagulation, as lifelong anticoagulation exposes the patient to considerable cumulative risk. However, a lack of high quality studies makes choosing a duration of anticoagulation after CVST difficult. In this article, we review the evidence for different treatment durations in several common clinical scenarios of CVST. In addition, when no direct evidence is available, we discuss and extrapolate from the more comprehensively studied situation of systemic venous thromboembolic disease. Recommendations are graded using standard criteria for the level of evidence.

Congenital heart disease in pregnancy

Heart disease is a main cause of maternal mortality in the United States and the United Kingdom. Most deaths are from acquired conditions. However, due to the increased survival of children born with congenital heart disease (CHD) over the past 30 years, the population of adults with congenital heart disease in the U.S. now exceeds 1 million. Thus, there are now more adults with CHD than children with CHD. Many of these adult survivors of pediatric heart disease are of childbearing age and are considering pregnancy. This article reviews the literature concerning pregnancy and CHD.

Evaluating patient values and preferences for thromboprophylaxis decision making during pregnancy: a study protocol

BACKGROUND

Pregnant women with prior venous thromboembolism (VTE) are at risk of recurrence. Low molecular weight heparin (LWMH) reduces the risk of pregnancy-related VTE. LMWH prophylaxis is, however, inconvenient, uncomfortable, costly, medicalizes pregnancy, and may be associated with increased risks of obstetrical bleeding. Further, there is uncertainty in the estimates of both the baseline risk of pregnancy-related recurrent VTE and the effects of antepartum LMWH prophylaxis. The values and treatment preferences of pregnant women, crucial when making recommendations for prophylaxis, are currently unknown. The objective of this study is to address this gap in knowledge.

METHODS

We will perform a multi-center cross-sectional interview study in Canada, USA, Norway and Finland. The study population will consist of 100 women with a history of lower extremity deep vein thrombosis (DVT) or pulmonary embolism (PE), and who are either pregnant, planning pregnancy, or may in the future consider pregnancy (women between 18 and 45 years). We will exclude individuals who are on full dose anticoagulation or thromboprophylaxis, who have undergone surgical sterilization, or whose partners have undergone vasectomy. We will determine each participant's willingness to receive LMWH prophylaxis during pregnancy through direct choice exercises based on real life and hypothetical scenarios, preference-elicitation using a visual analog scale ("feeling thermometer"), and a probability trade-off exercise. The primary outcome will be the minimum reduction (threshold) in VTE risk at which women change from declining to accepting LMWH prophylaxis. We will explore possible determinants of this choice, including educational attainment, the characteristics of the women's prior VTE, and prior experience with LMWH. We will determine the utilities that women place on the burden of LMWH prophylaxis, pregnancy-related DVT, pregnancy-related PE and pregnancy-related hemorrhage. We will generate a "personalized decision analysis" using participants' utilities and their personalized risk of recurrent VTE as inputs to a decision analytic model. We will compare the personalized decision analysis to the participant's stated choice.

DISCUSSION

The preferences of pregnant women at risk of VTE with respect to the use of antithrombotic therapy remain unexplored. This research will provide explicit, quantitative expressions of women's valuations of health states related to recurrent VTE and its prevention with LMWH. This information will be crucial for both guideline developers and for clinicians.

Maternal obesity and venous thromboembolism

The incidence of obesity in pregnancy has increased rapidly in the last decade. Obesity is a risk factor for venous thromboembolism outside of pregnancy and previous studies of maternal death in the UK have identified obesity as a risk factor in pregnancy. As a result the Royal College of Obstetricians and Gynaecologists have targeted obesity as a risk factor in evaluation of the need for thromboprophylaxis in pregnancy. This article highlights the evidence that obesity increases the risk of venous thromboembolism in pregnancy and the puerperium, discusses thromboprophylaxis and appropriate dosing in obese parturients and details the anaesthetic implications of the 2009 Royal College of Obstetricians and Gynaecologists' guidelines. More clinical studies are required to clarify the appropriate dose of low-molecular-weight heparin in an obese parturient.

The risk and outcomes of epidural hematomas after perioperative and obstetric epidural catheterization: a report from the Multicenter Perioperative Outcomes Group Research Consortium

BACKGROUND

In this study, we sought to determine the frequency and outcomes of epidural hematomas after epidural catheterization.

METHODS

Eleven centers participating in the Multicenter Perioperative Outcomes Group used electronic anesthesia information systems and quality assurance databases to identify patients who had epidural catheters inserted for either obstetrical or surgical indications. From this cohort, patients undergoing laminectomy for the evacuation of hematoma within 6 weeks of epidural placement were identified.

RESULTS

Seven of 62,450 patients undergoing perioperative epidural catheterizations developed hematoma requiring surgical evacuation. The event rate was 11.2 × 10(-5) (95% confidence interval [CI], 4.5 × 10(-5) to 23.1 × 10(-5)). Four of the 7 had anticoagulation/antiplatelet therapy that deviated from American Society of Regional Anesthesia guidelines. None of 79,837 obstetric patients with epidural catheterizations developed hematoma (upper limit of the 95% CI, 4.6 × 10(-5)). The hematoma rate in obstetric epidural catheterizations was significantly lower than in perioperative epidural catheterizations (P = 0.003).

CONCLUSIONS

In this series, the 95% CI for the frequency of epidural hematoma requiring laminectomy after epidural catheter placement for perioperative anesthesia/analgesia was 1 event per 22,189 placements to 1 event per 4330 placements. Risk was significantly lower in obstetric epidurals.

The risk of postpartum hemorrhage in women using high dose of low-molecular-weight heparins during pregnancy

BACKGROUND

Low-molecular-weight heparins (LMWH) are the most commonly used anticoagulant during pregnancy for prevention or treatment of VTE. However, the size of the associated risk of postpartum haemorrhage (PPH) is unknown.

OBJECTIVE

To assess the bleeding risk of high dose LMWH, also in relation to time between last dose LMWH and delivery.

MATERIAL AND METHODS

From 1999 to 2009, we followed 88 pregnant women who were started on therapeutic anticoagulation. Controls were pregnant women without LMWH, matched 1:4 for parity, mode of delivery, age, gestational age and delivery date. PPH was defined as >500 ml blood loss for vaginal delivery (severe PPH in vaginal delivery as >1000 ml) and >1000 ml for cesarean section (CS). Women were divided into subgroups by the interval between last dose of anticoagulation and delivery (<12, 12-24 hrs, >24 hrs).

RESULTS

Risk of PPH after vaginal delivery was 30% and 18% for LMWH-users and non-users, respectively (OR 1.9, 95%CI 1.1-3.5). Risk of severe PPH after vaginal delivery was not different (5.6 vs 5.0%; OR 1.1; 0.4-3.6). Risk of PPH after CS was 12% in LMWH-users and 4% in non-users (OR 2.9; 0.5-19.4). Both events of LMWH-users occurred after emergency CS. The risk of PPH associated with delivery within 24 hours after last dose of LMWH was 1.2 fold higher (95%CI 0.4-3.6) compared to a larger interval.

CONCLUSION

High dose LMWH carries an increased risk of more than 500 mL blood loss after vaginal delivery. However, this results not in more clinical relevant severe PPHs. The interval between last dose of LMWH and delivery does not influence the risk of PPH.

Maternal valvular heart disease in pregnancy

Valvular heart disease is common in pregnancy. Maternal physiology changes significantly during gestation with substantial increases in cardiac output and blood volume; this can cause unmasking or worsening of cardiac disease. Acquired valvular lesions most frequently arise from rheumatic fever, especially in patients who have emigrated from developing nations. Congenital lesions are also encountered. The most common conditions seen, mitral stenosis and regurgitation and aortic stenosis and regurgitation, each require a specific evaluation and management and are associated with their own set of possible complications. Patients with prosthetic valves require anticoagulation, and maternal and fetal risks and benefits must be carefully weighed. Patients with heart disease should be meticulously managed preconceptionally up to the postpartum period by maternal-fetal medicine specialists, obstetricians, cardiologists, and anesthesiologists using a multi-disciplinary approach to their cardiac conditions.

TARGET AUDIENCE

Obstetricians & Gynecologists and Family Physicians.

LEARNING OBJECTIVES

After the completing the CME activity, physicians should be better able to examine the epidemiology of valvular heart disease in pregnancy, categorize key physiologic parameters that change in the cardiovascular system during pregnancy, classify the pathophysiology of valvular lesions, and evaluate the general principles of maternal and fetal management for cardiac disease.

Comparative incidence of a first thrombotic event in purely obstetric antiphospholipid syndrome with pregnancy loss: the NOH-APS observational study

The incidence of thrombosis in the purely obstetric form of antiphospholipid syndrome is uncertain. We performed a 10-year observational study of 1592 nonthrombotic women who had experienced 3 consecutive spontaneous abortions before the 10th week of gestation or 1 fetal death at or beyond the 10th week of gestation. We compared the frequencies of thrombotic events among women positive for antiphospholipid Abs (n = 517), women carrying the F5 6025 or F2 rs1799963 polymorphism (n = 279), and women with negative thrombophilia screening results (n = 796). The annual rates of deep vein thrombosis (1.46%; range, 1.15%-1.82%), pulmonary embolism (0.43%; range, 0.26%-0.66%), superficial vein thrombosis (0.44%; range, 0.28%-0.68%), and cerebrovascular events (0.32%; range, 0.18%-0.53%) were significantly higher in aPLAbs women than in the other groups despite low-dose aspirin primary prophylaxis. Women carrying 1 of the 2 polymorphisms did not experience more thrombotic events than women who screened negative for thrombophilia. Lupus anticoagulant was a risk factor for unprovoked proximal and distal deep and superficial vein thrombosis and women in the upper quartile of lupus anticoagulant activity had the highest risk. Despite data suggesting that aPLAbs may induce pregnancy loss through nonthrombotic mechanisms, women with purely obstetric antiphospholipid syndrome are at risk for thrombotic complications.

Pregnancy-associated venous thromboembolism: prevention and treatment

Pregnancy is associated with an increased risk of venous thromboembolism (VTE) and this condition remains an important cause of maternal morbidity and mortality. The use of anticoagulant therapy for treatment and prophylaxis of VTE during pregnancy is challenging because of the potential for fetal, as well as maternal, complications. Although evidence-based recommendations for the use of anticoagulants have been published, given the paucity of available data, guidelines are based largely upon observational studies and from data in nonpregnant patients. This article reviews the available literature and provides guidance for the management and prevention of VTE during pregnancy.

Thrombin generation post elective caesarean section: effect of low molecular weight heparin

INTRODUCTION

Caesarean section (CS) is a significant risk factor for venous thromboembolism.. Low molecular weight heparin (LMWH) is commonly used for thromboprophylaxis post emergency caesarean delivery. However, no consensus exists regarding LMWH thromboprophylaxis following elective caesarean section. Measures of thrombin formation may indicate the full anticoagulant activity of LMWH in this setting.

MATERIALS AND METHODS

Anti-Xa, tissue factor pathway inhibitor (TFPI), thrombin anti-thrombin complex (TAT) and endogenous thrombin potential (ETP) were measured in twenty healthy women who received 4,500 IU tinzaparin 6 hours post CS (CS1), twenty women who received 4,500 IU tinzaparin at 10-12 hours post delivery (CS2) and twenty women post spontaneous vaginal delivery (SVD).

RESULTS

Prior to initiation of LMWH, TAT levels at 6 hours post delivery were significantly higher in the CS1 and CS2 groups than the SVD group (P<0.002); TAT levels were significantly reduced up to 24 hours post LMWH treatment despite declining anti-Xa levels (P<0.001). In CS1, peak thrombin and ETP were significantly reduced following LMWH prophylaxis (P<0.0001; P<0.002) and reverted to pre-delivery levels 10 hours post LMWH. TFPI levels mirror anti-Xa levels during the 24 hours following LMWH treatment in CS1 group with peak levels coinciding with peak anti-Xa levels 4 hours post injection.

CONCLUSION

In women post caesarean section, anti-Xa levels do not reflect the full anticoagulant effects of LMWH. In-vivo thrombin production (TAT) is effectively reduced even when anti-Xa levels are negligible. LMWH thromboprophylaxis in this healthy cohort of patients appears to have a sustained effect in reducing excess thrombin production post elective caesarean section.

Thrombophylaxis and bleeding complications after cesarean section

OBJECTIVE

To evaluate the safety of different regimes of thromboprophylaxis with low molecular weight heparins (LMWHs) in women undergoing cesarean section.

DESIGN

Retrospective single-center cross-sectional study.

SETTING

University Medical Center, The Netherlands.

POPULATION

All women that delivered by cesarean section in the Erasmus Medical Center, Rotterdam, between January 2004 and December 2007 received thromboprophylaxis. We included women who received thromboprophylaxis according to the routine administration schedule at that time.

METHODS

Three different consecutive regimes of thromboprophylaxis were used. In the first period, women received dalteparin 5000IU pre- and postoperatively (group A), in the second period, nadroparin 5700IU was administered pre- and postoperatively (group B), and in the third period, nadroparin 2850IU was administered not earlier than 6-12 hours postoperatively (group C). Detailed information on individual characteristics, cesarean section and postpartum period were extracted from patient files.

MAIN OUTCOME MEASURES

Postoperative bleeding complications.

RESULTS

A total of 1527 women were eligible and included. In group B, significantly more women experienced bleeding complications (necessitating either conservative treatment or re-laparotomy) compared with the other two groups (19/574 women in group B vs. 9/647 in group A and 1/306 in group C). After adjusting for potential confounders (maternal age, body mass index, and occurrence of preeclampsia/hemolysis, elevated liver enzymes and low platelet count) these effects remained significant (p=0.005). The incidence of thromboembolism was not different in the three groups.

CONCLUSIONS

Different regimes of thromboprophylaxis in women with cesarean section influenced the occurrence of bleeding complications.

A survey of the clinical course and management of Japanese patients deficient in natural anticoagulants

Few data are available on the clinical course of Japanese patients deficient in natural anticoagulants (antithrombin (AT), protein C, and protein S). We conducted a nationwide survey to reveal the clinical course of these patients. Questionnaires were sent to 321 council members of the Japanese Society on Thrombosis and Hemostasis, Japanese Society for Vascular Surgery, and Japanese Society of Phlebology. A total of 103 responses were obtained and data of 183 patients were collected. Of 183 patients, 142 (78%) experienced at least one episode of venous thromboembolism (VTE). The first VTE occurred before the age of 40 years in 71 patients (45%). Venous thromboembolism recurred in 15 (39%) patients with AT deficiency and 19 (18%) patients with other deficiencies. These findings suggest that half of the first episodes of VTE in patients deficient in natural anticoagulants occur before middle age and the risk of VTE recurrence is high in patients with AT deficiency.

Treatment of Neurocritical Care Emergencies in Pregnancy

OPINION STATEMENT: Neurologic emergencies are a major cause of morbidity and mortality in pregnant women. In part because the patient population is young, the nihilistic approach that often accompanies neurologically devastating disorders in other contexts is largely absent. A number of studies have demonstrated improved patient outcomes in the setting of aggressive care delivered by neurointensivists in a specialty-specific environment. It stands to reason that young, pregnant women who suffer from neurologically devastating disorders and who have a wide range of prognosis may also benefit from such specialized care. Close collaboration between obstetricians and neurointensivists is critical in this context. A number of unique considerations in diagnosis and management present dilemmas in the context of pregnancy, such as radiation dose from diagnostic neuroimaging, choice of pharmacotherapy for seizures, anticoagulation, and the method of delivery in the context of cerebral mass lesions and elevated intracranial pressure. Patients and their physicians are often faced with the additional challenge of balancing the relative risks and benefits of the impact of a management approach on both mother and fetus. In general, this balance tends to favor the interests of the mother, but the impact on the fetus becomes more relevant over the course of the pregnancy, especially in the third trimester. A low threshold for admission to an intensive care unit (ideally one that specializes in neurointensive care) should be used for pregnant patients. Because of the limited information regarding long-term outcomes in this population, rigid prognosis formation and early care limitations should be deferred in the immediate period. After the patient is stabilized and a plan has been charted for the remainder of the pregnancy, every effort should be made to engage patients in aggressive, urgent neurologic rehabilitation.