Natural anticoagulants deficiency and the risk of venous thromboembolism: a meta-analysis of observational studies

Duration of anticoagulation of venous thromboembolism

Venous thromboembolism (VTE) is a common, serious condition that requires anticoagulation for at least three months to prevent recurrence and long-term complications. After this initial period, the decision to continue or stop anticoagulation depends on the balance between the risk of recurrent VTE and the risk of bleeding. Established guidelines suggest short-term anticoagulation for VTE caused by transient factors and indefinite anticoagulation for recurrent or cancer-associated VTE. However, for a first unprovoked VTE, decision-making remains challenging. Current predictive scores for recurrence and bleeding are not sufficiently reliable, and the safety and efficacy of reduced-dose anticoagulation remain unclear. In the future, precision and patient-centred medicine may improve treatment decisions in this area.

Venous thromboembolism risk in adults with hereditary thrombophilia: a systematic review and meta-analysis

This systematic review and meta-analysis assesses venous thromboembolism (VTE) risk in adults with hereditary thrombophilia, including Factor V Leiden (FVL) mutation, prothrombin G20210A (FII) mutation, compound heterozygosity, protein C (PC), protein S (PS), and antithrombin (AT) deficiency. Eligibility criteria included studies suitable for quantitative synthesis with extractable information on VTE risk in adults (> 15 years). There were no restrictions on VTE type, location, or occurrence. Two authors reviewed all studies and extracted data from 107 publications, encompassing 107,130 individuals (21,560 experiencing VTE). We used a random effects model and calculated odds ratios (ORs) with 95% confidence intervals (CIs). The highest risk was associated with homozygous FVL (OR 5.58, 95% CI 4.61-6.74), homozygous FII (OR 5.16, 95% CI 3.12-8.52), and compound heterozygosity (OR 4.64, 95% CI 2.25-9.58). In contrast, VTE risk was lowest for FVL heterozygosity (OR 2.97, 95% CI 2.41-3.67) and FII heterozygosity (OR 2.21, 95% CI 1.70-2.87), whereas PC (OR 3.23, 95% CI 2.05-5.08), PS (OR 3.01, 95% CI 2.26-4.02), and AT deficiency (OR 4.01, 95% CI 2.50-6.44) demonstrated an intermediate VTE risk. These results highlight an increased risk of venous thromboembolism in adults with hereditary thrombophilia. However, the risk for patients with PC, PS, and AT deficiency appears to be lower than previously stated, likely due to varying thrombogeneity of the underlying genetic mutations. Further research addressing this aspect of VTE risk in hereditary thrombophilia is imperative to improve patient management. TRIAL REGISTRATION: PROSPERO registration number CRD42022376757.

Perioperative management of venous recanalization in a patient with inherited antithrombin deficiency: case report

Background

Inherited antithrombin (AT) deficiency (ATD) is a severe thrombophilia causing venous thromboembolism, which can be complicated by postthrombotic syndrome (PTS). Venous recanalization, used to treat PTS, often requires a temporary withdrawal of anticoagulant therapy. In ATD patients, there is a risk of insufficient perioperative anticoagulation due to altered heparin response.

Key Clinical Question

There is no consensus on how to manage perioperative anticoagulation in ATD patients.

Clinical Approach

Warfarin-unfractionated heparin transition could be a more reliable strategy than low-molecular-weight heparin transition because unfractionated heparin anti-Xa activity not only reflects heparin-bound AT but also AT's activity, which correlates strongly with therapeutic anticoagulation. Biological monitoring could thus decrease the number of plasma-derived AT supplementation.

Conclusion

This study describes a successful perioperative management of anticoagulation for venous recanalization that could be suggested to type 1 ATD patients with PTS.

Analysis of PROC mutations and clinical features in 22 unrelated families with inherited protein C deficiency

Currently, limited information is available in the literature regarding the relationships between PROC mutations and clinical features in Chinese individuals. We aimed to characterize severe congenital Protein C deficiency in 22 unrelated Chinese families in a tertiary hospital by analyzing its clinical manifestation, associated risk factors, and gene mutations. We measured protein C activity and antigen levels for all participants, screened them for mutations in the PROC gene, and analyzed the clinical features of each family to identify commonalities and differences. The analysis revealed a total of 75 individuals with PCD and 16 different PROC mutations, including 12 missense mutations and 4 deletion mutations. Among them, 11 who were compound heterozygotes or homozygotes for mutations tended to develop symptoms at a younger age without any clear triggers. In contrast, the remaining 64 individuals who were heterozygotes for mutations often had clear triggers for their symptoms and experienced a milder course of the disease. It is worth noting that the mutation c.565C > T occurred most frequently, being identified in 8 out of 22 families (36%). Our team also reported five novel mutations, including c.742-744delAAG, c.383G > A, c.997G > A, c.1318C > T, and c.833T > C mutations. The identification of five novel mutations adds to the richness of the Human Genome Database. Asymptomatic heterozygotes are not uncommon, and they are prone to develop symptoms with obvious triggers. The evidence presented strongly suggest that asymptomatic individuals with family history of protein C deficiency can benefit from mutational analysis of PROC gene.

A Comprehensive Review of Risk Factors and Thrombophilia Evaluation in Venous Thromboembolism

Venous thromboembolism (VTE), which encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE), is a significant cause of morbidity and mortality worldwide. There are many factors, both acquired and inherited, known to increase the risk of VTE. Most of these result in increased risk via several common mechanisms including circulatory stasis, endothelial damage, or increased hypercoagulability. Overall, a risk factor can be identified in the majority of patients with VTE; however, not all risk factors carry the same predictive value. It is important for clinicians to understand the potency of each individual risk factor when managing patients who have a VTE or are at risk of developing VTE. With this, many providers consider performing a thrombophilia evaluation to further define a patient's risk. However, guidance on who to test and when to test is controversial and not always clear. This comprehensive review attempts to address these aspects/concerns by providing an overview of the multifaceted risk factors associated with VTE as well as examining the role of performing a thrombophilia evaluation, including the indications and timing of performing such an evaluation.

Tissue Injury Protection: The Other Face of Anticoagulant Treatments in the Context of Ischemia and Reperfusion Injury with a Focus on Transplantation

Organ transplantation has enhanced the length and quality of life of patients suffering from life-threatening organ failure. Donors deceased after brain death (DBDDs) have been a primary source of organs for transplantation for a long time, but the need to find new strategies to face organ shortages has led to the broadening of the criteria for selecting DBDDs and advancing utilization of donors deceased after circulatory death. These new sources of organs come with an elevated risk of procuring organs of suboptimal quality. Whatever the source of organs for transplant, one constant issue is the occurrence of ischemia-reperfusion (IR) injury. The latter results from the variation of oxygen supply during the sequence of ischemia and reperfusion, from organ procurement to the restoration of blood circulation, triggering many deleterious interdependent processes involving biochemical, immune, vascular and coagulation systems. In this review, we focus on the roles of thrombo-inflammation and coagulation as part of IR injury, and we give an overview of the state of the art and perspectives on anticoagulant therapies in the field of transplantation, discussing benefits and risks and proposing a strategic guide to their use during transplantation procedures.

Molecular basis of inherited protein C deficiency results from genetic variations in the signal peptide and propeptide regions

BACKGROUND

Inherited protein C deficiency (PCD) caused by mutations in protein C (PC) gene (PROC) increases the risk of thrombosis. Missense mutations in PC's signal peptide and propeptide have been reported in patients with PCD, but their pathogenic mechanisms, except mutations in R42 residue, remain unclear.

OBJECTIVES

To investigate the pathogenic mechanisms of inherited PCD caused by 11 naturally occurring missense mutations in PC's signal peptide and propeptide.

METHODS

Using cell-based assays, we evaluated the impact of these mutations on various aspects such as activities and antigens of secreted PC, intracellular PC expression, subcellular localization of a reporter protein, and propeptide cleavage. Additionally, we investigated their effect on pre-messenger RNA (pre-mRNA) splicing using a minigene splicing assay.

RESULTS

Our data revealed that certain missense mutations (L9P, R32C, R40C, R38W, and R42C) disrupted PC secretion by impeding cotranslational translocation to the endoplasmic reticulum or causing endoplasmic reticulum retention. Additionally, some mutations (R38W and R42L/H/S) resulted in abnormal propeptide cleavage. However, a few missense mutations (Q3P, W14G, and V26M) did not account for PCD. Using a minigene splicing assay, we observed that several variations (c.8A>C, c.76G>A, c.94C>T, and c.112C>T) increased the incidence of aberrant pre-mRNA splicing.

CONCLUSION

Our findings suggest that variations in PC's signal peptide and propeptide have varying effects on the biological process of PC, including posttranscriptional pre-mRNA splicing, translation, and posttranslational processing. Additionally, a variation could affect the biological process of PC at multiple levels. Except for W14G, our results provide a clear understanding of the relationship between PROC genotype and inherited PCD.

Hemostatic considerations for gender affirming care

Gender dysphoria or gender incongruence is defined as "persons that are not satisfied with their designated gender" [1]. The awareness and evidence-based treatment options available to this population have grown immensely over the last two decades. Protocols now include an Endocrine Society Clinical Practice Guideline [1] as well as the World Professional Association of Transgender Health Standards of Care (WPATH SOC) [2]. Hematologic manifestations, most notably thrombosis, are one of the most recognized adverse reactions to the hormones used for gender-affirming care. Therefore, hematologists are frequently consulted prior to initiation of hormonal therapy to help guide safe treatment. This review will focus on the scientific evidence related to hemostatic considerations for various gender-affirming therapies and serve as a resource to assist in medical decision-making among providers and patients.

Case report: A case of new mutation in SERPINC1 leading to thrombotic microangiopathy

Introduction: Hereditary antithrombin-III deficiency can significantly increase the risk for thrombosis, which is common in limb deep vein and pulmonary cases. However, thrombotic microangiopathy (TMA) caused by hereditary antithrombin deficiency is rare. Case Presentation: We reported the case of a 32-year-old Chinese female patient with TMA with renal injury caused by decreased antithrombin-III activity due to a new mutation (chr1-173884049 c.50A>G) in SERPINC1, which encodes antithrombin-III. In this case, the patient had no history of relevant drug use, diabetes, or monoclonal plasma cells in the bone marrow puncture. Consequently, TMA of the kidney was considered secondary to hereditary antithrombin-III deficiency. Gene detection was the only clue that led us to suspect that TMA was caused by hereditary antithrombin deficiency. Conclusion: Our findings indicated that for patients with repeated findings of antithrombin-III activity less than 50%, the possibility of antithrombin-III deficiency and complete gene detection must be considered immediately after excluding the use of anticoagulants and lack of availability to facilitate early detection, diagnosis, and intervention.

Antithrombin Deficiency and Thrombosis: A Wide Clinical Scenario Reported in a Single Institution

Congenital antithrombin (AT) deficiency represents the form of thrombophilia with the highest thrombotic risk. It is characterized by a heterogeneous clinical presentation, depending mostly on the family history of thrombosis and type of genetic mutation. Inherited AT deficiency promotes idiopathic thrombosis at an early age (even in the pediatric population) and at atypical sites. Therefore, a positive family background necessitates ruling out this high-risk thrombophilia at a young age. Studying first-degree relatives, even if they are asymptomatic, is essential to establish thromboprophylaxis and a proper therapeutic approach in case of thrombosis. Patients with congenital AT deficiency require indefinite anticoagulation owing to the high thrombotic recurrence rate. Here, we present four unrelated cases reported in our institution who were diagnosed with hereditary AT deficiency, with a contrasting clinical evolution.

Post-viral idiopathic purpura fulminans is associated with inherited thrombophilia and anti-cardiolipin antibodies

Introduction

Idiopathic purpura fulminans (IPF) is a rare and severe coagulation disorder, associated with transient anti-protein S (anti-PS) antibodies in the context of post-viral infection such as varicella. Anti-protein S antibodies are frequently found in the context of varicella, in contrast with the rarity of IPF. Other factors such as anti-phospholipid antibodies (APL) and inherited thrombophilia may be associated with severe vascular complication.

Method

This is an ancillary study of a French multicenter retrospective series and systematic review of literature. We analyzed patients who were tested for inherited thrombophilia, namely antithrombin, protein C, protein S deficiency; prothrombin gene G20210A polymorphism (FII:G20210A),Factor V R506Q polymorphism (FV:R506Q); and/or for APL (lupus anticoagulant (LA), anti-cardiolipin antibodies (ACL), or anti-beta 2-GPI antibodies (Aβ2GP1).

Results

Among the 25 patients tested for inherited thrombophilia, 7 (28%) had positive results. Three had FV R506Q, two FII:G20210A, one compound heterozygote FV:R506Q associated to FII:G20210A, and one protein C deficiency. APL testing was performed in 32 patients. It was positive in 19 patients (59%): 17 ACL (53%), 5 LA (16%), 4 Aβ2GP1 (13%). The risk of severe complications was not associated with presence of inherited thrombophilia or APL presence, with RR: 0.8 [95% CI: 0.37-1.71], p = 1 and RR: 0.7 [95% CI: 0.33-1.51], p = 0.39, respectively. We found a high prevalence of inherited thrombophilia or APL in a population of patients with IPF. However, we do not find an association with the occurrence of severe vascular complications or venous thromboembolism.

Antithrombin diagnostics by mass spectrometry: Development and analytical validation of a next-generation test

Background

Antithrombin deficiency is a rare but severe disorder leading to high risk of thrombosis. The current clinical care pathway relies on activity tests, which only provide overall functional information on the in vitro activity of antithrombin. However, antithrombin exists in many different forms, also known as proteoforms, with varying clinical phenotypes. Precision diagnostics, facilitated by mass spectrometry, provides a strategy to improve patient diagnostics by molecular characterization.

Objectives

To develop and analytically validate a mass spectrometry-based test for molecular characterization of antithrombin.

Methods

The test was analytically validated based on predefined analytical performance specifications. The validation covered imprecision, carryover, linearity, stability, analytical specificity, a provisional reference interval, and an explorative method comparison.

Results

The test passed the predefined analytical performance specifications with a mean within-laboratory imprecision of 5.9%, linearity between 0.08 and 2.58 μmol/L, and a provisional reference interval of 1.07 to 1.49 μmol/L. When measuring samples with a suspected quantitative deficiency, the test showed a good correlation with a commercial activity test (Pearson r = 0.88).

Conclusion

The test passed the validation, and we now envision the use of the test for exploration of the clinical relevance of specific antithrombin proteoforms. Puzzling cases of antithrombin deficiency, for instance, due to ambiguous activity results or an atypical clinical presentation, can be investigated by the LC-MRM mass spectrometry test serving as an add-on to the activity test and providing a molecular diagnosis. Clinical studies are planned to investigate the potential of the test to improve antithrombin diagnostics. Furthermore, the molecular information gained using the test may aid in establishing better risk stratification and a basis for personalized medicine.

Transgender Medicine and Risk of Venous Thromboembolism

Gender dysphoria refers to psychological distress that results from an incongruence between gender identity and sex assigned at birth. Administration of sex hormones is most often used as a first step to develop and maintain physical characteristics consistent with gender identity. Gender-affirming hormone treatment is considered beneficial for the quality of life and reduction of depression. However, estrogen and androgen-lowering hormone therapies used in transwomen are in particular associated with increased risk of venous thromboembolism. In this review, introduced by a clinical case, we provide an overview of the currently available medical therapies in transgender medicine, and put the associated increased risk of venous thromboembolism into perspective.

Management of Antithrombin Deficiency in Pregnancy

Antithrombin (AT) deficiency is a high-risk thrombophilia and a rare condition. The risk of venous thromboembolism (VTE) is increased in AT-deficient women during pregnancy and the postpartum period and is especially high in women with a prior history of VTE. A thorough assessment of VTE risk is recommended in pregnant AT-deficient women, comprising the degree and type of AT deficiency, genetic mutations, personal and family history, and additional preexisting or pregnancy-specific risk factors. Due to a lack of adequate study data, there is limited guidance on the management of AT deficiency in pregnancy, including the need for prophylactic anticoagulation, the appropriate dose of low-molecular-weight heparin (LMWH), and the role of AT substitution. LMWH is the medication of choice for the pharmacological prophylaxis and treatment of VTE in pregnancy. Patients with a history of VTE should receive full-dose LMWH during pregnancy and the postpartum period. AT concentrates are a treatment option when anticoagulation is withheld in potentially high-risk events such as childbirth, bleeding, or surgery and in cases of acute VTE despite the use of therapeutic dose anticoagulation. Women with AT deficiency should be counseled at specialized centers for coagulation disorders or vascular medicine, and close cooperation between obstetricians and anesthesiologists is warranted before delivery and during the peripartum period.

Microsurgical Breast Reconstruction in Patients with Disorders of Hemostasis: Perioperative Risks and Management

BACKGROUND

Surgical and technological advances have resulted in the widespread adoption of microsurgical breast reconstruction. Many comorbidities that potentially might impair vasculature and wound healing are no longer considered contraindications for these procedures. However, some uncertainty still prevails regarding the perioperative management of patients with disorders of hemostasis.

METHODS

The authors combined a literature review with a retrospective chart review of patients with disorders of hemostasis who had undergone microsurgical breast reconstruction at the senior author's (J.F.) center between 2015 to 2020. Several disorders associated with thrombotic and/or hemorrhagic complications were identified, and a standardized risk assessment and management strategy was developed in cooperation with a hematologist.

RESULTS

Overall, 10 studies were identified comprising 29 patients who had a defined disorder of hemostasis and underwent microsurgical breast reconstruction. Seventeen microsurgical breast reconstructions were performed on 11 patients at the senior author's (J.F.) center. High factor VIII levels, heterozygous factor V Leiden, and heterozygous prothrombin mutation G20210A were the most common genetic or mixed genetic/acquired thrombophilic conditions. As expected, hereditary antithrombin, protein C, or protein S deficiencies were rare. Among hemorrhagic disorders, thrombocytopenia, platelet dysfunction, and von Willebrand disease or low von Willebrand factor levels were those factors most frequently associated with increased perioperative bleeding.

CONCLUSIONS

Patients should be screened for elevated risk of thrombosis or bleeding before undergoing microsurgical breast reconstruction, and positive screening should prompt a complete hematologic evaluation. Interdisciplinary management of these disorders with a hematologist is essential to minimize risks and to obtain optimal reconstructive results.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, IV.

Evolving Knowledge on Primary and Secondary Prevention of Venous Thromboembolism in Carriers of Hereditary Thrombophilia: A Narrative Review

The association between heritability of venous thromboembolism (VTE) and thrombophilia was first reported clinically in 1956, later followed by the first description of a congenital cause of hypercoagulability-antithrombin deficiency-in 1965. Since then, our knowledge of hereditary causes of hypercoagulability, which may predispose carriers to VTE has improved greatly. Novel genetic defects responsible for severe thrombophilia have been recently identified and we have learned that a wide range of interactions between thrombophilia and other genetic and acquired risk factors are important determinants of the overall individual risk of developing VTE. Furthermore, therapeutic strategies in thrombophilic patients have benefited significantly from the introduction of direct oral anticoagulants. The present review is an overview of the current knowledge on the mechanisms underlying inherited thrombophilia, with a particular focus on the latest achievements in anticoagulation protocols and prevention strategies for thrombosis in carriers of this prothrombotic condition.

Evolving Knowledge on Primary and Secondary Prevention of Venous Thromboembolism in Carriers of Hereditary Thrombophilia: A Narrative Review

The association between heritability of venous thromboembolism (VTE) and thrombophilia was first reported clinically in 1956, later followed by the first description of a congenital cause of hypercoagulability-antithrombin deficiency-in 1965. Since then, our knowledge of hereditary causes of hypercoagulability, which may predispose carriers to VTE has improved greatly. Novel genetic defects responsible for severe thrombophilia have been recently identified and we have learned that a wide range of interactions between thrombophilia and other genetic and acquired risk factors are important determinants of the overall individual risk of developing VTE. Furthermore, therapeutic strategies in thrombophilic patients have benefited significantly from the introduction of direct oral anticoagulants. The present review is an overview of the current knowledge on the mechanisms underlying inherited thrombophilia, with a particular focus on the latest achievements in anticoagulation protocols and prevention strategies for thrombosis in carriers of this prothrombotic condition.

How Would You Treat This Patient With Pulmonary Embolism? : Grand Rounds Discussion From Beth Israel Deaconess Medical Center

Pulmonary embolism can be acutely life-threatening and is associated with long-term consequences such as recurrent venous thromboembolism and chronic thromboembolic pulmonary hypertension. In 2020, the American Society of Hematology published updated guidelines on the management of patients with venous thromboembolism. Here, a hematologist and a cardiology and vascular medicine specialist discuss these guidelines in the context of the care of a patient with pulmonary embolism. They discuss advanced therapies such as catheter-directed thrombolysis in the short-term management of patients with intermediate-risk disease, recurrence risk stratification at presentation, and ideal antithrombotic regimens for patients whose pulmonary embolism was associated with a transient minor risk factor.

Predicting the risk of recurrent venous thromboembolism: Impact and therapeutic consequences of inherited thrombophilia

BACKGROUND

Over the past decades, thrombophilia testing in patients with venous thrombo-embolism has increased tremendously. However, the role of inherited thrombophilie in prediction the risk of recurrence remains controversial. Consequently, it is still unclear whether thrombophilia testing influences decisions regarding duration of anticoagulation in clinical practices. The aim of this study was to evaluate the impact if inherited thrombophilia on venous thrombosis treatment decisions and on predicting the risk of recurrence.

METHODS

A retrospective longitudinal study (January 2011-Decembre 2016) including 131 patients with confirmed venous thrombo-embolism referred to the hematology laboratory from the internal medicine department for inherited thrombophilia screening was carried out.

RESULTS

The mean age patients was 39.4 years and the sex ratio (M/F) was 0.61. Inherited thrombophilia was confirmed in 27.5% of patients. A long term anticoagulation was decided in 46.9% of patients with thrombophilia. There was no significant difference in the duration of anticoagulation between patients with or without thrombophilia. Thrombosis recurrence was recorded in 16 (17%) patients. The 24 years cumulative incidence of recurrence was 19% in patients with thrombophilia and 17% in those without (plog Rank= 0.6). Inherited thrombophilia was not associated with increased risk of recurrence after treatment withdrawal (Hazard ratio=1.31 IC (0.47-3.63); P=0.6).

CONCLUSION

In clinical practice, inherited thrombophilia did not influence anticoagulation duration and was not associated with a higher venous thrombosis risk of recurrence. It seems to be less relevant for decision making than presumed.

Detection of Unknown and Rare Pathogenic Variants in Antithrombin, Protein C and Protein S Deficiency Using High-Throughput Targeted Sequencing

The deficiency of natural anticoagulants—antithrombin (AT), protein C (PC), and protein S (PS)—is a highly predisposing factor for thrombosis, which is still underdiagnosed at the genetic level. We aimed to establish and evaluate an optimal diagnostic approach based on a high-throughput sequencing platform suitable for testing a small number of genes. A fast, flexible, and efficient method involving automated amplicon library preparation and target sequencing on the Ion Torrent platform was optimized. The cohort consisted of a group of 31 unrelated patients selected for sequencing due to repeatedly low levels of one of the anticoagulant proteins (11 AT-deficient, 13 PC-deficient, and 7 PS-deficient patients). The overall mutation detection rate was 67.7%, highest in PC deficiency (76.9%), and six variants were newly detected—SERPINC1 c.398A > T (p.Gln133Leu), PROC c.450C > A (p.Tyr150Ter), c.715G > C (p.Gly239Arg) and c.866C > G (p.Pro289Arg), and PROS1 c.1468delA (p.Ile490fs) and c.1931T > A (p.Ile644Asn). Our data are consistent with those of previous studies, which mostly used time-consuming Sanger sequencing for genotyping, and the indication criteria for molecular genetic testing were adapted to this process in the past. Our promising results allow for a wider application of the described methodology in clinical practice, which will enable a suitable expansion of the group of indicated patients to include individuals with severe clinical findings of thrombosis at a young age. Moreover, this approach is flexible and applicable to other oligogenic panels.

Inherited Thrombophilia in the Era of Direct Oral Anticoagulants

Severe inherited thrombophilia includes rare deficiencies of natural anticoagulants (antithrombin and proteins C and S) and homozygous or combined factor V Leiden and FII G20210A variants. They are associated with a high thrombosis risk and can impact the duration of anticoagulation therapy for patients with a venous thromboembolism (VTE) event. Therefore, it is important to diagnose thrombophilia and to use adapted anticoagulant therapy. The widespread use of direct anticoagulants (DOACs) for VTE has raised new issues concerning inherited thrombophilia. Concerning inherited thrombophilia diagnosis, DOACs are directed toward either FIIa or FXa and can therefore interfere with coagulation assays. This paper reports DOAC interference in several thrombophilia tests, including the assessment of antithrombin, protein S, and protein C activities. Antithrombin activity and clot-based assays used for proteins C and S can be overestimated, with a risk of missing a deficiency. The use of a device to remove DOACs should be considered to minimize the risk of false-negative results. The place of DOACs in the treatment of VTE in thrombophilia patients is also discussed. Available data are encouraging, but given the variability in thrombosis risk within natural anticoagulant deficiencies, evidence in patients with well-characterized thrombophilia would be useful.

Unraveling a borderline antithrombin deficiency case with quantitative mass spectrometry

Antithrombin deficiency diagnostics by first-line activity tests suffer from a lack of sensitivity sometimes resulting in diagnostic uncertainty. We here present a case of a woman with recurrent pregnancy loss who was screened for inherited thrombophilia. Antithrombin activity was borderline low, resulting in uncertainty about the correct diagnosis. Using a mass spectrometry-based test, the antithrombin protein of the patient was characterized at the molecular level and a heterozygous p.Pro73Leu mutation was identified. The mutation, also known as antithrombin "Basel," increases the risk of venous thromboembolism and obstetric complications. This case is illustrative of current antithrombin deficiency screening, in which diagnoses may be missed by traditional diagnostics. Next-generation protein diagnostics by mass spectrometry provides molecular insight into the proteoforms present in vivo. This information is essential for laboratory specialists and clinicians to unambiguously diagnose patients and will aid in evolving healthcare from traditional to precision diagnostics.

Hereditary Antithrombin Deficiency: A Balancing Act of Perioperative Hemostasis and Thromboprophylaxis-A Case Report

Hereditary deficiency of antithrombin (AT) is associated with increased risk of venous thromboembolism (VTE), especially under the circumstances of stress, vascular injury, and immobilization associated with surgery. To date, there is no consensus on the use of perioperative anticoagulant bridging in the setting of hereditary thrombophilia. Balancing hemorrhagic and thrombotic risks associated with anticoagulant bridging and AT deficiency can be challenging to perioperative physicians. We present a case of a 65-year-old woman with inherited AT deficiency with history of multiple VTEs who was admitted for presurgical anticoagulant bridging before microvascular decompression craniotomy for trigeminal neuralgia.

Genetic Variants in the Protein S ( PROS1 ) Gene and Protein S Deficiency in a Danish Population

Protein S (PS) deficiency is a risk factor for venous thromboembolism (VTE) and can be caused by variants of the gene encoding PS ( PROS1 ). This study aimed to evaluate the clinical value of molecular analysis of the PROS1 gene in PS-deficient participants. We performed Sanger sequencing of the coding region of the PROS1 gene and multiplex ligation-dependent probe amplification to exclude large structural rearrangements. Free PS was measured by a particle-enhanced immunoassay, while PS activity was assessed by a clotting method.

A total of 87 PS-deficient participants and family members were included. In 22 index participants, we identified 13 PROS1 coding variants. Five variants were novel. In 21 index participants, no coding sequence variants or structural rearrangements were identified. The free PS level was lower in index participants carrying a PROS1 variant compared with index participants with no variant (0.51 [0.32–0.61] vs. 0.62 [0.57–0.73] × 10 ³ IU/L; p  < 0.05). The p.(Thr78Met) variant was associated with only slightly decreased free PS levels (0.59 [0.53–0.66] × 10 ³ IU/L) compared with the p.(Glu390Lys) variant (0.27 [0.24–0.37] × 10 ³ IU/L, p  < 0.01). The frequency of VTE in participants with a coding PROS1 variant was 43 and 17% in the group with normal PROS1 gene ( p  = 0.05).

In conclusion, we report 13 PROS1 coding variants including five novel variants. PS levels differ by PROS1 variant and the frequency of VTE was higher when a coding PROS1 variant was present. Hence, molecular analysis of the PROS1 gene may add clinical value in the diagnostic work-up of PS deficiency.

Perioperative Management of Orthopaedic Patients with Hematologic Disorders: A Critical Analysis Review

Perioperative management of orthopaedic patients with a hematologic disorder is a complex endeavor that requires a multidisciplinary team-based approach. A team composed of an experienced orthopaedic surgeon, an anesthesiologist, and a hematologist is necessary to achieve optimal outcomes. Patients with hemophilia and other complex hematologic disorders should be managed at, or in consultation with a hematologist at, a comprehensive hemophilia center. Bleeding disorders and inherited thrombophilia present unique challenges for the perioperative management of orthopaedic surgery. Comprehensive preoperative planning and familiarity with treatment guidelines can help to minimize these risks. Knowledge of the disease processes outlined in this article will provide orthopaedic surgeons with the requisite background knowledge that is needed to initiate safe and effective treatment strategies involving this high-risk patient population.

Osteonecrosis of the Femoral Head in Patients with Hypercoagulability-From Pathophysiology to Therapeutic Implications

Osteonecrosis of the femoral head (ONFH) is a debilitating disease with major social and economic impacts. It frequently affects relatively young adults and has a predilection for rapid progression to femoral head collapse and end-stage hip arthritis. If not diagnosed and treated properly in the early stages, ONFH has devastating consequences and leads to mandatory total hip arthroplasty. The pathophysiology of non-traumatic ONFH is very complex and not fully understood. While multiple risk factors have been associated with secondary ONFH, there are still many cases in which a clear etiology cannot be established. Recognition of the prothrombotic state as part of the etiopathogeny of primary ONFH provides an opportunity for early medical intervention, with implications for both prophylaxis and therapy aimed at slowing or stopping the progression of the disease. Hereditary thrombophilia and hypofibrinolysis are associated with thrombotic occlusion of bone vessels. Anticoagulant treatment can change the natural course of the disease and improve patients' quality of life. The present work focused on highlighting the association between hereditary thrombophilia/hypofibrinolysis states and ONFH, emphasizing the importance of identifying this condition. We have also provided strong arguments to support the efficiency and safety of anticoagulant treatment in the early stages of the disease, encouraging etiological diagnosis and prompt therapeutic intervention. In the era of direct oral anticoagulants, new therapeutic options have become available, enabling better long-term compliance.

Ilio-femoral venous thrombosis with hereditary antithrombin deficiency: a case report of rare thrombotic disease and successful treatment with catheter directed thrombolysis

Background

Hereditary antithrombin (AT) deficiency is an uncommon autosomal dominant thrombogenic disorder, which can cause venous thromboembolism (VTE). Although conservative treatment options for hereditary AT deficiency-associated VTE such as anticoagulation (warfarin, direct oral anticoagulant, or heparin), intravenous thrombolysis, and recombinant AT are well known, interventional treatment options have not been reported so far.

Case summary

A 19-year-old man with a family history of thrombogenic diseases, referred to our hospital with left leg pain, was diagnosed with AT deficiency-associated VTE. In the absence of symptomatic relief with intravenous thrombolysis and anticoagulation, he received venous intervention and catheter directed thrombolysis (CDT) for 4 days for left iliac venous thrombosis. Following a second venous intervention, venous thrombus disappeared almost entirely on cross-sectional imaging, and his symptoms improved. He was discharged on apixaban and has been recurrence-free for one and a half years.

Discussion

This case presents CDT and maintenance therapy with apixaban as possible treatment options for VTE in patients with hereditary AT deficiency, especially following failure of conservative therapy. Individual risks and benefits should be considered when CDT is performed for acute VTE in patients with AT deficiency.

Serpins in Hemostasis as Therapeutic Targets for Bleeding or Thrombotic Disorders

Bleeding and thrombotic disorders result from imbalances in coagulation or fibrinolysis, respectively. Inhibitors from the serine protease inhibitor (serpin) family have a key role in regulating these physiological events, and thus stand out as potential therapeutic targets for modulating fibrin clot formation or dismantling. Here, we review the diversity of serpin-targeting strategies in the area of hemostasis, and detail the suggested use of modified serpins and serpin inhibitors (ranging from small-molecule drugs to antibodies) to treat or prevent bleeding or thrombosis.

The Effect of Direct Oral Anticoagulants on Antithrombin Activity Testing Is Abolished by DOAC-Stop in Venous Thromboembolism Patients

CONTEXT.—

Direct oral anticoagulants (DOACs) may cause false negative results of antithrombin (AT) deficiency screening.

OBJECTIVE.—

To evaluate the impact of DOAC-Stop, an agent reversing in vitro effects of DOACs, on AT testing in anticoagulated patients.

DESIGN.—

We assessed 130 venous thromboembolism patients aged 46.7 ± 13.5 years. Blood samples were collected 2 to 27 hours after DOAC intake from 49 patients on rivaroxaban, 54 on apixaban, and 27 on dabigatran. Antithrombin activity was assessed using the activated factor X (FXa)-based and the activated factor II (FIIa)-based method twice, before and after DOAC-Stop treatment, together with plasma DOAC levels using coagulometric assays.

RESULTS.—

The use of DOAC-Stop did not influence AT activity measured using the FIIa-based assay, whereas there was a marked decrease in AT activity determined using the FXa-based assay (ΔAT = 16.9%; 95% CI, 12.9%-19.1%). The AT-FIIa assay revealed decreased AT level (<79%) in all 10 (7.7%) genetically confirmed AT-deficient patients treated with rivaroxaban or apixaban (n = 5 each), whereas the AT-FXa assay showed decreased AT activity (<83%) in 2 subjects on rivaroxaban and 1 on apixaban with low plasma DOAC concentrations (<90 ng/mL). After DOAC-Stop median AT-FXa activity lowered from 83.5% (interquartile range, 66%-143%) to 65.5% (interquartile range, 57%-75%; P = .005; ΔAT = 18%) in AT-deficient patients, without any false negative results. The ΔAT in the FXa-based assay correlated with rivaroxaban and apixaban concentrations in the AT-deficient patients (r = 0.99, P < .001).

CONCLUSIONS.—

Application of DOAC-Stop enables reliable evaluation of AT deficiency screening in patients taking rivaroxaban or apixaban and tested using the FXa-based method.

Antithrombin p.Thr147Ala: The First Founder Mutation in People of African Origin Responsible for Inherited Antithrombin Deficiency

BACKGROUND

 Hereditary antithrombin deficiency is a rare autosomal-dominant disorder predisposing to recurrent venous thromboembolism (VTE). To date, only two founder mutations have been described.

OBJECTIVES

 We investigated the antithrombin p.Thr147Ala variant, found in 12 patients of African origin. This variant is known as rs2227606 with minor allele frequency of 0.5% in Africans and absent in Europeans. A possible founder effect was investigated.

METHODS

 Phenotypical characterization was established through immunological and functional methods, both under basal and stress conditions. Recombinant antithrombin molecules were constructed by site-directed mutagenesis and expressed in HEK-293T cells. Secreted antithrombin was purified and functionally characterized. Structural modeling was performed to predict the impact of the mutation on protein structure. A novel nanopore sequencing approach was used for haplotype investigation.

RESULTS

 Ten patients experienced VTE, stroke, or obstetric complications. Antithrombin antigen levels and anti-IIa activity were normal or slightly reduced while anti-Xa activity was reduced with only one commercial assay. On crossed immunoelectrophoresis, an increase of antithrombin fractions with reduced heparin affinity was observed under high ionic strength conditions but not under physiological conditions. The recombinant p.Thr147Ala protein displayed a reduced anti-Xa activity. Structural modeling revealed that residue Thr147 forms three hydrogen bonds that are abolished when mutated to alanine. The investigated patients shared a common haplotype involving 13 SERPINC1 intragenic single nucleotide polymorphisms.

CONCLUSION

 Antithrombin p.Thr147Ala, responsible for antithrombin type II heparin binding site deficiency, is the first founder mutation reported in people of African ancestry. This study further emphasizes the limitations of commercial methods to diagnose this specific subtype.

Genotype-Phenotype Relationships in a Large French Cohort of Subjects with Inherited Protein C Deficiency

Inherited protein C (PC) deficiency caused by mutations in the PROC gene is a well-known risk factor for venous thromboembolism. Few studies have investigated the relationship between PROC genotype and plasma or clinical phenotypes. We addressed this issue in a large retrospective cohort of 1,115 heterozygous carriers of 226 PROC pathogenic or likely pathogenic mutations. Mutations were classified in three categories according to their observed or presumed association with type I, type IIa, or type IIb PC deficiency. The study population comprised 876 carriers of type I category mutations, 55 carriers of type IIa category mutations, and 184 carriers of type IIb category mutations. PC anticoagulant activity significantly influenced risk of first venous thrombosis (p trend < 10^-4). No influence of mutation category on risk of whole or unprovoked thrombotic events was observed. Both PC anticoagulant activity and genotype significantly influenced risk of venous thrombosis. Effect of detrimental mutations on plasma phenotype was ambiguous in several carriers, whatever the mutation category. Altogether, our findings confirm that diagnosing PC inherited deficiency based on plasma measurement may be difficult but show that diagnosis can be improved by PROC genotyping.

Managing thromboembolic risk in patients with hereditary and acquired thrombophilias

While we are now able to diagnose inherited thrombophilias in a substantial number of patients with venous thromboembolism (VTE), the initial hope that their presence would inform recurrence risk and thus decisions on anticoagulation duration has largely been disappointing. Indeed, the presence or absence of transient provoking risk factors has proven to be the most important determinant of VTE recurrence risk. Thus, particular attention to transient acquired risk factors for VTE remains paramount, as they have generally been shown to carry more prognostic weight than inherited thrombophilias. The presence of other acquired risk factors may require additional management considerations, whether pertaining to anticoagulant choice, as in antiphospholipid antibody syndrome, or to addressing a new predisposing medical condition, as in malignancy. Antithrombin deficiency or the presence of ≥1 thrombophilic defect may be exceptions that can have a role in prognostication; however, as illustrated in this review through several case vignettes, interpretation and clinical application of the results of inherited thrombophilia testing is nuanced. We have chosen to focus on cases in which patients have been identified as having thrombophilic defects rather than the indications for undertaking testing in the first place or the extent of investigation. Management decisions in such cases ultimately hinge on individualized consideration of the benefits and risks of anticoagulation along with patient preference rather than on an algorithmic pathway based on thrombophilia status.

Protein S for Portal Vein Thrombosis in Cirrhotic Patients Waiting for Liver Transplantation

Portal vein thrombus (PVT) is a challenge in liver transplantation. How PVT develops in cirrhotic patients who already have coagulopathy is unclear. This study aimed to investigate possible contributing factors to PVT in cirrhotic patients. A total of 349 cirrhotic patients who waited liver transplantation were included in this study and 48 of them had PVT. For all the patients, the mean age was 53.5 ± 9.0 year old, and 75.9% of the patients were male. There were 233 (66.8%) patients who had either hepatitis B or C. The mean Model For End-Stage Liver Disease (MELD) score was 16.4 ± 7.5. Eighteen of 48 patients with PVT and 145 of 301 patients without PVT received liver transplantation. Multivariate analysis showed that low protein S level (hazard ratio = 2.46, p = 0.017) was the only independent risk factor for PVT development. Protein S deficiency also demonstrated prognostic value on short-term survival, not only for cirrhotic patients awaiting liver transplantation (69.9% versus 84.1% at 1 year survival, p = 0.012), but also for the patients having liver transplantation (70.4% versus 84.8% at 1 year survival, p = 0.047). In conclusion, protein S level was an independent risk factor for PVT development in decompensated cirrhotic patients, and protein S deficiency was also a prognostic factor for the patients waiting for liver transplantation.

Thrombophilia evaluation in pulmonary embolism

PURPOSE OF REVIEW

Patients with pulmonary embolism commonly undergo thrombophilia evaluation for a variety of reasons including risk stratification for recurrent venous thromboembolism (VTE) and treatment planning. However, the utility of thrombophilia testing in many clinical scenarios remains unclear. This review evaluates current recommendations for thrombophilia testing described in consensus VTE guidelines, recent literature on the clinical application of these recommendations, novel genetic assessments for hereditary thrombophilias, and studies evaluating use of direct oral anticoagulants (DOACs) in VTE patients with thrombophilias.

RECENT FINDINGS

Current VTE guidelines advise limited use of thrombophilia testing, recognizing that testing may be misinterpreted and frequently does not lead to a change in management. Testing and test results are not necessarily benign, are frequently misinterpreted, and can lead to increased anxiety in both patients and clinicians. Recent studies have offered innovative techniques to better align clinical practice with these recommendations as well as expanded genomic assessments to improve the scope and predictive value of thrombophilia testing. There is also emerging literature on the appropriateness of direct oral anticoagulant therapy for VTE patients with hereditary thrombophilias or antiphospholipid syndrome.

SUMMARY

Thrombophilia testing in its current form does not significantly impact clinical management or improve outcomes for most VTE patients. Therefore, it should be employed judiciously and only in patients for whom it is likely to alter clinical management. Novel expanded genomic thrombophilia testing approaches and additional studies evaluating optimal anticoagulant treatment in various thrombophilia subpopulations will make thrombophilia testing more useful for patients moving forward.

Prevalence and Outcomes of Thrombophilia in Patients with Acute Pulmonary Embolism

Background

We aimed to study the prevalence and outcomes of thrombophilia in acute pulmonary embolism.

Methods

A retrospective observational study was conducted to include patients with a radiologically confirmed diagnosis of PE screened for thrombophilia from May 2011 to February 2015. Data included patients’ demographics; clinical presentation, risk factors, laboratory investigations, management, and outcome were analyzed and compared in patients with and without thrombophilia.

Results

A total of 227 cases of PE were included in the study, of which 108 (47.6%) had thrombophilia. The most frequent coagulopathic abnormality included deficiency of protein S, protein C, and antithrombin III and hyperhomocysteinemia. Only seven out of 79 patients were found to have factor V Leiden. PE patients diagnosed with thrombophilia were 10 years younger in age and peaked in the age range 30–39 years. Prior history of DVT (p=0.001) and PE (p=0.001) were the main significant risk factors in the thrombophilia group. The frequency of different risk categories of clinical probability scores did not differ significantly among those with and without thrombophilia. Pulmonary hypertension was a common complication in the thrombophilia group (P=0.009). Medications used included warfarin (74.7%), enoxaparin (73.9%), and heparin (55.4%). The overall mortality rate was 8.4%, and was non-significantly higher in the non-thrombophilia group.

Conclusion

Deficiencies of protein S, protein C, and antithrombin III are the leading causes of thrombophilic defects. Patients with hereditary thrombophilia are at increased risk of acute PE, particularly among young individuals. Therefore, early detection of thrombophilic defects together with other unprovoked risk factors could reduce the risk of recurrent VTE.

Advances in the diagnosis of acute pulmonary embolism

Venous thromboembolism is a common disease which remains underdiagnosed because of nonspecific presentations which can range from asymptomatic incidental imaging findings to sudden death. Symptoms can overlap with comorbid cardiopulmonary disease, and risk factors that offer clues to the clinician are not always present. The diagnostic approach can vary depending on the specific clinical presentation, but ruling in the diagnosis nearly always depends on lung imaging. Overuse of diagnostic testing is another recognized problem; a cautious, evidence-based approach is required, although physician gestalt must be acknowledged. The following review offers an approach to the diagnosis of acute pulmonary embolism based on the assessment of symptoms, signs, risk factors, laboratory findings, and imaging studies.

Hereditary Antithrombin Deficiency Presenting with Deep Venous Thrombosis During the Second Pregnancy

A 37-year-old woman developed deep venous thrombosis (DVT) of the left lower extremity at 8 weeks of gestation during her second pregnancy. There was no personal or family history of thrombosis. She received intravenous heparin, but heparin resistance was noted. The plasma antithrombin activity decreased to 45% in the acute phase, and it remained low postpartum. Her mother also had low plasma antithrombin activity (46%), and genetic testing revealed a heterozygous SERPINC1 mutation. Even without a family history of thrombosis, we should suspect hereditary antithrombin deficiency in patients with initial DVT and perform thorough investigation.

Protein C deficiency; PROC gene variants in a Danish population

INTRODUCTION

Protein C deficiency is a heritable thrombophilia caused by numerous different genetic alterations in the protein C (PROC) gene. We aimed to identify variants causing protein C deficiency in a Danish population.

MATERIAL AND METHODS

Sanger sequencing of the PROC gene was performed in 20 probands and 26 relatives. In total, 30participants were previously diagnosed with protein C deficiency. Protein C activity was measured by a chromogenic substrate method (N = 40) and antigen level by an enzyme-linked immunosorbent assay (N = 26).

RESULTS

Ten different single nucleotide variants were detected in 13 probands (65%) and in seven of the relatives previously diagnosed with protein C deficiency. Five variants were novel. The median protein C activity level was lower in participants with an identified variant (50% (range: 38-75%)) than in protein C deficient participants without a variant (65% (range: 36-73%); P = 0.18). A protein C activity of 57% resulted in the highest detection rate (12/13 (92%)). Likewise, the median antigen level was lower in participants with detectable variants than in participants without (49% (range: 35-99%) vs 70% (range: 41-101%); P = 0.09). No difference was found in venous thromboembolism (VTE) prevalence comparing participants with (12/20 (60%)) and without (7/10 (70%)) a variant (P = 0.59).

CONCLUSION

In a Danish population, a PROC gene variant was identified in 67% of participants previously diagnosed with protein C deficiency. Five variants were novel. The study confirmed an association between biochemical severity and the presence of a PROC gene variant. The VTE risk did not seem to differ between protein C deficient participants with and without a variant.

Antithrombin concentrate during pregnancy in congenital antithrombin deficiency: a single-center experience

: Pregnancy carries a high risk of thromboembolic complications, especially in the postpartum period. This risk is particularly high in women with inherited thrombophilias, among these antithrombin deficiency seems to carry the highest risk. In this case, the use of low molecular weight heparin (LMWH) is recommended, while the use of antithrombin concentrate is controversial. We report our experience of seven pregnancies occurred in five women: two, with a personal and familiar history negative for venous thromboembolism, were treated with LMWH during pregnancy and antithrombin concentrate immediately before and after the delivery. The other three women had a personal and familiar history positive for venous thromboembolism and were treated with LMWH and antithrombin concentrate during all the pregnancy and the postpartum period. No thromboembolic or hemorrhagic complications were observed in both groups, demonstrating that our strategy could be safe and effective.

Management of antithrombin deficiency: an update for clinicians

Introduction. Antithrombin is a serpin that inhibits multiple procoagulant serine proteases and acts as an endogenous anticoagulant. Thus, congenital antithrombin deficiency constitutes a major thrombophilic state, the most severe so far. Areas covered. In the present work, we globally review the biology, genetics, diagnosis, and management of congenital antithrombin deficiency, and also discuss puzzling questions and future perspectives regarding this severe inherited thrombophilia. Expert opinion. Although this disorder exerts high clinical heterogeneity, many carriers will need careful and long-term anticoagulation and/or thromboprophylaxis, especially in high-risk situations, such as surgery and pregnancy. Notably, antithrombin concentrates constitute a considerable arsenal for both treatment and prevention of acute venous thrombosis in subjects with antithrombin deficiency. Current evidences are based almost exclusively on retrospective case series, so an integrated functional, biochemical and molecular characterization will be of clinical relevance and guide hematologists' personalized decisions.

SERPINC1 variants causing hereditary antithrombin deficiency in a Danish population

INTRODUCTION

Antithrombin deficiency is associated with increased risk of venous thromboembolism (VTE). We aimed to identify variants causing antithrombin deficiency in a Danish population.

MATERIALS AND METHODS

We performed Sanger sequencing and, in relevant cases, multiplex ligation-dependent probe amplification analyses, in 46 individuals (23 index cases) with and 9 relatives without antithrombin deficiency. Furthermore, in order to explore whether a combination of antithrombin type II heparin binding site (HBS) deficiency and factor V Leiden single nucleotide variant (SNV) conferred a higher risk of VTE than either risk factor alone, we performed genotyping for factor V Leiden in most of the carriers of type II HBS deficiency (n = 25).

RESULTS

We detected causal variants in all 46 carriers: three large and two small deletions, all causing type I antithrombin deficiency, and seven SNVs: one causing type I, one causing type II reactive site (RS), four causing type II HBS and one causing pleiotropic effect (PE) type II antithrombin deficiency. None of the relatives without antithrombin deficiency had the family variant. All detected SNVs have been reported previously. Majority (n = 27) of carriers had type II HBS deficiency, most often caused by the p.(Pro73Leu) SNV (n = 19). Heterozygosity for factor V Leiden was observed in three (3/25 = 12%) carriers of type II HBS deficiency. Only four (4/25 = 16%) carriers of type II HBS antithrombin deficiency experienced VTE, and two of these were heterozygous for factor V Leiden.

CONCLUSIONS

In a systematic search to identify variants causing hereditary antithrombin deficiency in a Danish population, we achieved a variant detection rate of 100%.

Hypercoagulable states in arterial and venous thrombosis: When, how, and who to test?

Evaluation for underlying hypercoagulable states in patients with thrombosis is a frequent clinical conundrum. Testing for thrombophilias is often reflexively performed without strategic approach nor clear appreciation of the clinical implications of such results. Guidelines vary in the appropriate utilization of thrombophilia testing. In this review, we discuss the more commonly encountered inherited and acquired thrombophilias, their association with initial and recurrent venous thromboembolism, arterial thromboembolism, and role in women's health. We suggest an approach to thrombophilia testing guided by the clinical presentation, suspected pathophysiology, and an understanding of how such results may affect patient care.

The influence of specific mutations in the AT gene (SERPINC1) on the type of pregnancy related complications

BACKGROUND

Inherited antithrombin (AT) deficiency is a rare autosomal dominant disorder, caused by mutations in the SERPINC1 gene. The most common clinical presentation in AT deficient patients includes venous thrombosis and pulmonary embolism, while the association of AT deficiency and its effect on the development of pregnancy complications has been less studied. The aim of our research was to evaluate the effect of AT deficiency types, determined by genotyping, on pregnancy outcomes.

METHODS

A retrospective cohort study included 28 women with AT deficiency, and their 64 pregnancies were analyzed.

RESULTS

With regard to live birth rate, a significant difference was observed among women who were carriers of different SERPINC1 mutations, as the rate varied from 100% in cases of type I to the extremely low rate of 8% for women with type II HBS (AT Budapest 3) in the homozygous variant, P = 0.0005. All pregnancies from the type I group, even untreated ones, resulted in live births. In women with AT Budapest 3 in homozygous variant the overall live birth rate increased to 28.5% in the treated pregnancies. In this group the highest incidence of fetal death was observed of 62%; repeated fetal losses in 30%; fetal growth restriction in 22% and placental abruption in 7% of all pregnancies.

CONCLUSION

Our study results indicate a difference between type I and type II AT deficiency. The risk of pregnancy related VTE was equally present in both groups, except for AT Budapest 3 in the heterozygous variant, while adverse pregnancy outcomes were strictly related to type II, especially AT Budapest 3 in the homozygous variant.

[Risk factors for thromboembolic disease in young women-the role of hormones]

Hormonal exposure in young women increases the risk of venous thromboembolic disease (VTE). Thrombophilia testing is often proposed in women of childbearing age before the initiation of contraception. However, the presence of a familial history of VTE has the potential to be more accurate than the presence of inherited thrombophilia.

OBJECTIVE

To demonstrate an association between the risk of VTE in young women with hormonal exposure (pregnancy or oral contraceptive use) and the presence of a previous episode of VTE in their first-degree relatives, according to whether or not a detectable inherited thrombophilia was present.

METHODS

We will perform a multicenter case-control cross-sectional study. The main risk factor is defined by the presence of a symptomatic VTE in young women with hormonal exposure. The principle variable is the presence of an objectively diagnosed episode of VTE in first-degree relatives. We will need to include 2,200 family members in 440 cases.

EXPECTED RESULTS

We expect to improve understanding of the thrombotic risk in first-degree relatives of patients in hormonal context with or without a past history of VTE.