Single and combined prothrombotic factors in patients with idiopathic venous thromboembolism: prevalence and risk assessment

Combined Parental Thrombophilia Gene Mutation Defects in Couples with Repeated Pregnancy Loss

Background

Several genetic mutations in female thrombotic defects have recently been shown to affect recurrent pregnancy loss (RPL); however, it is unclear which common parental mutations are involved in thrombosis-associated repeated pregnancy loss RPL.

Aims

In this study, the prevalence of some combined parental thrombophilia gene mutation defects was studied in couples with RPL.

Settings and Design

The observational study was done in babol infertility research center (Iran) in 2022.

Materials and Methods

Sixty-two infertile women with a history of RPL and their male partners (124 individuals) participated in this study. The frequencies of common defects associated with methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, factor V Leiden, protein C, protein S and homocysteine were analysed in these couples.

Statistical analysis used

The data were statistically analysed using the Mann-Whitney test.

Results

Sixty-two couples (124 individuals) were analysed. 56.2% of couples with a history of RPL had MTHFR C677T and 23.1% had MTHFR A1298C. Forty percent of couples showed homocysteine deficiency and 12.5% protein C deficiency. Other genes tested were only observed in the mother or father but not both.

Conclusions

Results obtained with RPL couples demonstrate the importance of further investigating combined parental thrombophilia gene mutation defects (not only maternal).

Research progress of NF-κB signaling pathway and thrombosis

Venous thromboembolism is a very common and costly health problem. Deep-vein thrombosis (DVT) can cause permanent damage to the venous system and lead to swelling, ulceration, gangrene, and other symptoms in the affected limb. In addition, more than half of the embolus of pulmonary embolism comes from venous thrombosis, which is the most serious cause of death, second only to ischemic heart disease and stroke patients. It can be seen that deep-vein thrombosis has become a serious disease affecting human health. In recent years, with the deepening of research, inflammatory response is considered to be an important pathway to trigger venous thromboembolism, in which the transcription factor NF-κB is the central medium of inflammation, and the NF-κB signaling pathway can regulate the pro-inflammatory and coagulation response. Thus, to explore the mechanism and make use of it may provide new solutions for the prevention and treatment of thrombosis.

Prothrombin G20210A Gene Mutation-Induced Recurrent Deep Vein Thrombosis and Pulmonary Embolism: Case Report and Literature Review

Inherited thrombophilia is an important cause of venous thrombosis. The Factor V Leiden (FVL) is the most commonly encountered mutation, followed by the prothrombin G20210A gene mutation (PTM). The typical venous thrombotic events (VTEs) associated with PTM mutations are deep vein thrombosis (DVT) and pulmonary embolisms (PE). The PTM is inherited in an autosomal dominant pattern with variable penetrance. While heterozygous PTM mutations are more frequent and well documented in the literature, rare cases of homozygous PTM mutations are also reported. In this report, we discuss a 56-year-old male with a past medical history of homozygous prothrombin gene mutation (G20210A) who presented with an unprovoked DVT of the right lower extremity involving both the proximal and distal veins associated with multiple bilateral PEs. This case is unique in terms of the homozygous PTM inheritance, the age at which the patient presented (usually presentation is earlier in life), and the fact that he had a recurrence of both DVT and PE simultaneously.

Outcomes in Head and Neck Free Flap Reconstruction Among Patients With a History of Venous Thromboembolism

OBJECTIVE

To investigate if a history of venous thromboembolism (VTE) is a risk factor for complications in head and neck free flap surgery by assessing outcomes among patients with a history of deep vein thrombosis (DVT) and/or pulmonary embolism (PE).

STUDY DESIGN

Retrospective cohort study.

SETTING

Single tertiary care center.

METHODS

All patients undergoing head and neck free flap reconstruction at our institution between September 1, 2006, and April 2, 2020, were assessed for inclusion. Patients with and without a history of DVT or PE preoperatively were identified and grouped for comparison. Groups were compared for demographics, comorbidities, and 30-day complications. Significance was assessed with chi-square and binary logistic regression analyses.

RESULTS

Of the 1061 patients meeting inclusion criteria, 40 (3.8%) had a history of VTE. These patients were significantly older (mean [SD], years: 67.8 [11.7] vs 63.0 [14.1], P = .038) and significantly more likely to have history of chemotherapy (35.0% vs 18.7%, P = .010) and stroke (27.5% vs 4.5%, P < .001). After accounting for patient characteristics via binary logistic regression, VTE was independently associated with an increased risk for postoperative thrombosis of the free flap pedicle (odds ratio [95% CI] = 3.65 [1.12-11.90], P = .032) and reoperation (2.45 [1.25-4.80], P = .009). Patients with history of PE had a significantly increased risk for flap failure (7.70 [1.77-33.52], P = .007). Prior VTE was not independently associated with an increased risk for medical complications or readmission.

CONCLUSION

Patients with a history of VTE may be at an increased risk for free flap compromise secondary to postoperative pedicle thrombosis. This risk should be considered in preoperative workup and postoperative monitoring.

c.259A>C in the fibrinogen gene of alpha chain (FGA) is a fibrinogen with thrombotic phenotype

Introduction

Dysfibrinogenemia is a rare inherited disease that results from mutation in one of the three fibrinogen genes. Diagnosis can be misleading since it may present as a bleeding tendency or thrombosis and a specific coagulation test for diagnosis is not routinely available

Aim

To search for a new candidate gene of thrombophilia in a family with three generations of arterial and venous thrombosis.

Methods

Whole exome sequencing followed by Sanger validation and segregation analysis was carried out. In addition, structural modeling was performed. Screening for thrombophilia along with blood counts, prothrombin time, activated partial thromboplastin, thrombin, reptilase time, and fibrinogen was done in each patient.

Results and discussion

A missense c.259A>C, p.K87Q (g.chr4: 155510050A-C) (rs764281241) in FGA gene was found in all three siblings without any other known thrombophilia marker to explain thrombosis in all three siblings. It is expected to be damaging by six out of seven prediction programs and is very rare in the entire population with Exac=0.000008.

Conclusion

The occurrence of the c.259A>C mutation in FGA may well explain the thrombosis phenotype of the affected family and is suggested as a new marker for thrombophilia phenotype.

Thrombophilia, risk factors and prevention

INTRODUCTION

Fifty-three years after the first description of an inherited prothrombotic condition (antithrombin deficiency), our knowledge on hereditary and acquired causes of hypercoagulability that can predispose carriers to venous thromboembolism (VTE) has greatly improved. Areas covered: Main causes of hereditary thrombophilia are summarized alongside new prothrombotic mutations recently discovered. The main causes of acquired thrombophilia, and namely, antiphospholipid antibody syndrome and hyperhomocysteinemia, are also discussed together with other common acquired prothrombotic states characterized by an increase of procoagulant factors and/or a decrease of natural anticoagulants. Finally, suggestions for thromboprophylaxis in carriers of hereditary thrombophilia according to current guidelines/evidence are made for the most challenging high-risk situations (i.e. surgery, pregnancy, contraception, cancer, economy class syndrome) as well as for the prevention of post-thrombotic syndrome. Expert opinion: A carrier of inherited thrombophilia should be evaluated in the framework of other (genetic and/or acquired) coexisting risk factors for first or recurrent VTE when assessing the need and duration of prevention (primary prophylaxis). Prevention strategies should be tailored to each patient and every situational risk factor. The knowledge of the carriership status of severe thrombophilia in the proband can be important to provide asymptomatic relatives with adequate counseling on thrombophilia screening or primary thromboprophylaxis.

High prevalence of factor V Leiden and prothrombin G20101A mutations in Kashmiri patients with venous thromboembolism

AIM

The genetic variants of the factor V (G1691A), prothrombin (G20210A) and MTHFR (C677T) genes have been widely implicated as inherited risk factors for developing venous thrombosis. This study was undertaken to reveal the frequency of these mutations in Kashmiri patients with venous thromboembolism.

METHODOLOGY

A case-control study was designed with 250 VTE patients and 250 healthy controls. The mutations were analysed using ARMS-PCR and PCR-RFLP approach.

RESULT

The factor V Leiden G1691A mutation was found in 17/250 (6.8%) VTE patients and prothrombin G20210A mutation was found in 7/250 (2.8%) VTE patients while no mutation was found in any of the healthy controls. Both the mutations were found to be significantly associated with the increased risk of VTE (p = 0.0001 and 0.0150 respectively) while no association of VTE risk with MTHFR C677T polymorphism was found (p = 0.53).

CONCLUSION

The increased frequency of factor V Leiden G1691A and prothrombin G20210A mutation in VTE patients indicates a significant role of these mutations in the development of VTE in our population. We therefore suggest the routine screening of these two mutations as thrombophilic markers in Kashmiri patients with venous thromboembolism.

Circulating microparticles in carriers of prothrombin G20210A mutation

Factor V Leiden (FVL) and prothrombin gene mutation G20210A (PTM) are the two most common genetic polymorphisms known to predispose carriers to venous thromboembolism (VTE). A recent study in FVL carriers showed that circulating levels of microparticles (MP) may contribute to their thrombogenic profile. To further elucidate the prothrombotic state linked to genetic thrombophilia, we extended this study to carriers of PTM. The plasma level of annexin V-MP, endothelial- MP (EMP), platelet-MP (PMP), tissue factor-bearing MP (TF+) and the MP procoagulant activity (PPL) was measured in 124 carriers of PTM (105 heterozygous and 19 homozygous) and in 120 age- and gender-matched healthy individuals. Heterozygous and homozygous carriers of PTM showed significantly increased levels of annexin V-MP (2930 [1440–4646] MP/μl and 3064 [2412–4906] MP/μl, respectively) and significantly shorter PPL clotting time (54 [46–67] sec and 55 [46–64] sec) compared to controls (1728 [782–2122] MP/μl and 71 [61–75] sec, respectively; p<0.01). Similarly, heterozygous and homozygous subjects presented with significantly higher levels of EMP, PMP and TF+ than controls (p<0.05). PTM carriers with a VTE history had significantly higher MP numbers and activity than controls. No significant difference was seen between carriers with and without a VTE history. We conclude that the higher levels of circulating MP found in PTM carriers may play a role in the development of VTE possibly by increasing thrombin generation. Further studies are needed to better define the role of MP as triggering factors for the thrombotic complications characterizing mild genetic thrombophilic defects.

Towards the genetic basis of cerebral venous thrombosis-the BEAST Consortium: a study protocol

INTRODUCTION

Cerebral venous thrombosis (CVT) is a rare cerebrovascular condition accounting for <1% of all stroke cases and mainly affects young adults. Its genetic aetiology is not clearly elucidated.

METHODS AND ANALYSIS

To better understand the genetic basis of CVT, we have established an international biobank of CVT cases, Biorepository to Establish the Aetiology of Sinovenous Thrombosis (BEAST) which aims to recruit highly phenotyped cases initially of European descent and later from other populations. To date we have recruited 745 CVT cases from 12 research centres. As an initial step, the consortium plans to undertake a genome-wide association analysis of CVT using the Illumina Infinium HumanCoreExome BeadChip to assess the association and impact of common and low-frequency genetic variants on CVT risk by using a case-control study design. Replication will be performed to confirm putative findings. Furthermore, we aim to identify interactions of genetic variants with several environmental and comorbidity factors which will likely contribute to improve the understanding of the biological mechanisms underlying this complex disease.

ETHICS AND DISSEMINATION

BEAST meets all ethical standards set by local institutional review boards for each of the participating sites. The research outcomes will be published in international peer-reviewed open-access journals with high impact and visibility. The results will be presented at national and international meetings to highlight the contributions into improving the understanding of the mechanisms underlying this uncommon but important disease. This international DNA repository will become an important resource for investigators in the field of haematological and vascular disorders.

Factor V Leiden Mutation and Other Thrombophilia Markers in Childhood Ischemic Stroke

The aim of this study was to evaluate the association between ischemic childhood stroke and thrombophilia. The prevalence of thrombophilia risk factors in 30 unrelated children with ischemic stroke were compared with 33 age-matched control subjects. Patients and control group were tested for the presence of activated protein C (APC) resistance, antiphospholipid antibodies (APLA), increased factor VIII levels, and for the deficiency of protein C (PC), protein S (PS), and antithrombin. When APCR was detected in patients or in controls, factor V Leiden (FVL) mutation was also tested. Seventeen of 30 patients (56.6%) had at least one thrombophilia marker compared with only 5 of 33 control subjects (15.1%). Three children with ischemic stroke (10%) were affected with a combination of two or more thrombophilia markers whereas none of the children in the control group had a combination of risk factors. Seven of 30 children with ischemic stroke (23.3%) and one of 33 control subjects (3.03%) had APC resistance and in all of them FVL mutation were found. The prevalence of FVL mutation was higher among pediatric stroke patients than among control subjects (p < 0.05). None of the patients but one child from the control group (3.03%) had PS deficiency. Antithrombin and PC deficiencies and the presence of APLA and increased factor VIII levels were more frequent in the pediatric stroke patients than in controls but the difference was not statistically significant (p > 0.05). These data confirm that stroke in children is commonly associated with a combination of multiple risk factors and especially the prevalence of FVL mutation is increased in children with ischemic stroke compared with control subjects.

Efficiency of Systematic Thrombophilia Screening in Idiopathic Venous Thrombosis: A Prospective Study in Internal Medicine

In case of unprovoked venous thromboembolism (VTE), the screening of thrombophilia is recommended whatever the age of the patient and the type of risk factors (RF). This prospective study was conducted in patients with unprovoked VTE to detect some predictive factors to have a higher risk of thrombophilia, focusing on age, history of venous thromboembolism, and the existence of a triggering event. From July 2000 to July 2002, in an Internal Medicine Department, unrelated patients with unprovoked VTE were included. Those unprovoked thromboembolic events were defined by the absence of association between permanent and transient RF. The primary outcome measure was the positivity of the thrombophilia screening for any type of abnormality detected (deficit of protein C, S, antithrombin, presence of a lupus anticoagulant, research of V and II mutations). Seventy-four patients were included. Eight died during the follow-up. A higher risk of thrombophilia was found in patients younger than 40 (p=0.03), or with a family but not personal history of VTE (p=0.01) or with transient RF (p=0.02). The most frequent abnormality of coagulation found in patients younger than 40 was the presence of a lupus anticoagulant. As a new strategy for the screening of thrombophilia, one could propose the following attitude: only patients with transient RF or family history of VTE could undergo a complete screening; for all the remaining patients who are younger than 40, a research of a lupus anticoagulant would be only performed. This strategy should now be balanced against the currently recommended systematic attitude in further studies.

Ramifications of Four Concurrent Thrombophilic Mutations and One Hypofibrinolytic Mutation

A kindred was examined in which the 48-year-old white female proband with three deep venous thrombosis-pulmonary emboli events had four thrombophilic and one hypofibrinolytic mutations, and in which her 14-year-old asymptomatic daughter had four thrombophilic mutations. The proband was heterozygous for the G1691A factor V Leiden, G20210A prothrombin, and platelet glycoprotein IIIa PL A1/A2 mutations, had high factor VIII (221%), and was homozygous for the 4G4G plasminogen activator inhibitor-1 gene mutation, with high plasminogen activator inhibitor activity (23.7 U/mL). Her 14-year-old daughter was homozygous for the G1691A factor V Leiden and platelet glycoprotein IIb-IIIa PL A2/A2 mutations, compound heterozygous for the C677T and A1298C methylenetetrahydrofolate reductase (MTHFR) mutations, and heterozygous for the G20210A prothrombin mutation, a combination with an estimated likelihood of 1.6 × 10-7. In 247 white healthy controls, there was no V Leiden homozygosity and no V Leiden-prothrombin gene compound heterozygosity. Heterozygosity for the V Leiden and prothrombin gene mutations was 3.2% and 4.1%, respectively. Homozygosity for the platelet glycoprotein IIb-IIIa PL A2A2, PAI-1 gene 4G4G, and C677T MTHFR mutations was 3.2%, 22.7%, and 12%, respectively. The proband will receive anticoagulation therapy for life. Beyond aspirin, avoidance of exogenous estrogens, and enoxaparin prophylaxis during pregnancy, it is not known whether the proband’s daughter should have lifelong anticoagulation therapy, or only after her first thrombotic event.

The Frequency of Factor V Leiden and Concomitance of Factor V Leiden With Prothrombin G20210A Mutation and Methylene Tetrahydrofolate Reductase C677T Gene Mutation in Healthy Population of Denizli, Aegean Region of Turkey

Factor V Leiden causing activated protein C resistance is the most common inherited form of thrombophilia leading to thrombosis. Its frequency shows great ethnic and geographic variations. The aim of this study was to determine the frequency of FV Leiden and coinheritance of FV Leiden with two other frequent hereditary thrombophilia causes, namely, prothrombin G20210A and methylene-tetrahydrofolate reductase ( MTHFR) C677T mutation in the Aegean region of Turkey. The study population consisted of 1030 (500 men and 530 women) apparently healthy subjects. Functional resistance to activated protein C (APC) was measured by using the test kit STA staclot APC-R ((Diagnostica Stago, Asnieres, France, Cat. No. 00721). In subjects with APC resistance, molecular analyses of FV Leiden and of prothrombin G20210A and MTHFR C677T mutation were performed by using FV-PTH-MTHFR StripA (Vienna Lab, Labordiagnostika GmbH, Austria) kit, which was based on hybridization of polymerase chain reaction (PCR) amplified DNA products with mutation-specific oligonucleotide probes. Functional APC resistance was present in 93 subjects (9%). FV Leiden mutation was found in 87 of 93 subjects with APC resistance by PCR method. The FV Leiden carrier frequency was found to be 8.4% (87/1030). Seventy-six individuals were heterozygous (7.3%), and 11 were homozygous (1.06%). Among the 87 subjects with FV Leiden mutation, 45 subjects had MTHFR C677T gene mutation (7 homozygous, 38 heterozygous) and 4 subjects had heterozygote prothrombin G20210A gene mutation. A combination of FV Leiden and prothrombin G20210A and MTHFR C677T gene mutation was detected in 3 subjects. The results indicate that FV Leiden prevalence is quite high and coexistence of FV Leiden with other hereditary causes of thrombosis such as prothrombin G20210A mutation and MTHFR enzyme defect is not rare in healthy population of Aegean region of Turkey.

Thrombophilic risk of individuals with rare compound factor V Leiden and prothrombin G20210A polymorphisms: an international case series of 100 individuals

The risk of thrombosis in individuals with rare compound thrombophilias, homozygous factor V Leiden (FVL) plus heterozygous prothrombin G20210A (PTM), homozygous PTM plus heterozygous FVL, and homozygous FVL plus homozygous PTM, is unknown. We identified, worldwide, individuals with these compound thrombophilias, predominantly through mailing members of the International Society on Thrombosis and Haemostasis. Physicians were sent a clinical questionnaire. Confirmatory copies of the genetic results were obtained. One hundred individuals were enrolled; 58% were female. Seventy-one individuals had a venous thrombosis (includes superficial and deep vein thrombosis, and pulmonary embolism), 4 had an arterial thrombosis and 6 had both. Nineteen individuals had never had a thrombotic event. Thrombosis-free survival curves demonstrated that 50% of individuals had experienced a thrombotic event by 35 yrs of age, while 50% had a first venous thromboembolic event (VTE; includes all venous thrombosis except superficial thrombosis) by 41 yrs of age; 38.2% of first VTEs were unprovoked. 37% of patients had at least one VTE recurrence. Seventy percent of first pregnancies carried to term and not treated with anticoagulation were thrombosis-free. In conclusion, patients with these rare compound thrombophilias are not exceedingly thrombogenic, even though they have a substantial risk for VTE.

Head trauma is the major risk factor for cerebral sinus-vein thrombosis

BACKGROUND

Cerebral sinus vein thrombosis (CSVT) is a rare disease with significant neurological sequelae and high mortality rate. Incidence of CSVT diagnosis in the western world has increased despite the reduced occurrence of infections.

AIM

To identify risk factors that may explain the predisposition to site specific thrombosis.

METHODS

Ninety consecutive patients diagnosed with acute CSVT in tertiary hospital. As a control group we used the data extracted from the National Trauma Registry and Healthcare Services.

RESULTS

Trauma history up to one month prior to diagnosis of CVST was found in 13 (14%) patients. Six patients had skull fractures, the others had blunt trauma. The overall SMR was 941 (p<0.0001); the separate results for men and women were 1206 and 543, respectively. Infections confined to the head and neck in 7% of the cases and brain tumor were observed in 8%. At the time of CVST, 23 of 50 (46%) women had a hormonal risk factor. The SMR for OC use was 1.63 (p=0.0298). Prothrombotic polymorphisms were detected in 16 of 63 (25.4%) patients who were tested for factor V Leiden and prothrombin G20210A mutation (OR=3.47, p=0.002) in comparison to 49% in DVT patients (OR=9.95, p<0.0001).

CONCLUSIONS

Assessment for CVST in patients with recent trauma and headache even after intact head CT is required. The other risk factors, such as hormone related and prothrombotic polymorphisms, were not specific just for CVST and the latter play a lesser role in CVST than in DVT.

The Contributions of Thrombophilic Mutations to Genetic Susceptibility to Deep Venous Thrombosis in Iraqi Patients

BACKGROUND AND AIMS

There is a paucity of data on the contribution of various thrombophilic mutations to the development of venous thrombosis in Iraqi patients. Therefore we designed a study to assess the frequencies of known thrombophilic mutations in this population.

METHODS

100 consecutive Iraqi patients with color Doppler confirmed deep venous thrombosis of the lower extremities and 100 age- and sex-matched healthy controls were enrolled in the study. Their DNAs were tested by multiplex polymerase chain reaction (PCR) followed by reverse hybridization for factor V Leiden (FVL), the prothrombin (PT) G20210A SNP, and the MTHFR C677T SNP. The factor V A4070G mutation was assessed by restriction fragment length polymorphism-PCR.

RESULTS

The prevalence of FVL was 13% in patients versus 2% in controls (odd ratios [OR] 7.3; p=0.007). Patients with recurrent thrombosis also had a significantly higher frequency of Factor V Leiden (OR 8.4, p=0.0007). The prothrombin G20210A, SNP, the factor V A4070G SNP, and the MTHFR 677 TT genotypes were present among patients at 5%, 9%, and 11%, respectively, and among controls at 2%, 6%, and 6%; none of these single mutation prevalence differences were significant. Interestingly, however, when these polymorphisms were studied in aggregate we found that 24% of patients had two or more thrombophilic alleles, compared to only 8% of the controls (OR 3.6; p=0.002). This subgroup included significantly more patients with proximal (p=0.007) and recurrent thrombosis (p=0.012), as well as younger patients (≤40 years) (p=0.026).

CONCLUSION

Two or more thrombophilic alleles, as well as FVL on its own, were both significantly associated with an increased risk of venous thrombosis and recurrence in Iraqi patients. Single thrombophilic mutations on their own were not associated with an increased risk.

Anticoagulation duration in heterozygous factor V Leiden: a decision analysis

BACKGROUND

Current anticoagulation guidelines suggest that optimal anticoagulation duration for unprovoked venous thromboembolism is determined by an individual risk assessment, balancing risks of anticoagulation bleeding with venous thromboembolism recurrence. Among individuals heterozygous for the factor V Leiden mutation, while venous thromboembolism recurrence risk is greater, the risk for bleeding is recognized to be lower, suggesting longer duration anticoagulation could be considered.

OBJECTIVE

The objective of this study was to compare standard vs. lifelong anticoagulation in 20-year-old factor V Leiden heterozygotes with unprovoked venous thromboembolism.

METHODS

A Markov state-transition model was used, incorporating risks of major, minor, and fatal anticoagulation bleeding, bleeding and thromboembolism morbidity and mortality, and quality of life utilities. Model parameter values favoring lifelong anticoagulation in factor V Leiden heterozygotes were determined in sensitivity analyses. Outcomes were in quality-adjusted life years, discounted at 3% per year.

RESULTS

In general population groups with odds ratios for venous thromboembolism recurrence and anticoagulation bleeding of 1.0, a short-term anticoagulation strategy gained 0.09 quality-adjusted life years more than a lifelong anticoagulation strategy. By contrast, in factor V Leiden heterozygotes, lifetime anticoagulation was favored if their relative risk of venous thromboembolism was greater than 1.07 or their relative risk for bleeding was less than 0.91. Results were relatively insensitive to individual variation in other parameter values.

CONCLUSION

Lifelong anticoagulation may benefit individuals heterozygous for factor V Leiden and previous idiopathic venous thromboembolism. Studies assessing bleeding risk with anticoagulation in factor V Leiden heterozygotes and the costs of indefinite anticoagulation are needed to determine if lifelong anticoagulation is the optimal strategy.

Risk of venous thromboembolism associated with single and combined effects of Factor V Leiden, Prothrombin 20210A and Methylenetethraydrofolate reductase C677T: a meta-analysis involving over 11,000 cases and 21,000 controls

Genetic and environmental factors interact in determining the risk of venous thromboembolism (VTE). The risk associated with the polymorphic variants G1691A of factor V (Factor V Leiden, FVL), G20210A of prothrombin (PT20210A) and C677T of methylentetrahydrofolate reductase (C677T MTHFR) genes has been investigated in many studies. We performed a pooled analysis of case-control and cohort studies investigating in adults the association between each variant and VTE, published on Pubmed, Embase or Google through January 2010. Authors of eligible papers, were invited to provide all available individual data for the pooling. The Odds Ratio (OR) for first VTE associated with each variant, individually and combined with the others, were calculated with a random effect model, in heterozygotes and homozygotes (dominant model for FVL and PT20210A; recessive for C677T MTHFR). We analysed 31 databases, including 11,239 cases and 21,521 controls. No significant association with VTE was found for homozygous C677T MTHFR (OR: 1.38; 95 % confidence intervals [CI]: 0.98-1.93), whereas the risk was increased in carriers of either heterozygous FVL or PT20210 (OR = 4.22; 95 % CI: 3.35-5.32; and OR = 2.79;95 % CI: 2.25-3.46, respectively), in double heterozygotes (OR = 3.42; 95 %CI 1.64-7.13), and in homozygous FVL or PT20210A (OR = 11.45; 95 %CI: 6.79-19.29; and OR: 6.74 (CI 95 % 2.19-20.72), respectively). The stratified analyses showed a stronger effect of FVL on individuals ≤ 45 years (p value for interaction = 0.036) and of PT20210A in women using oral contraceptives (p-value for interaction = 0.045). In this large pooled analysis, inclusive of large studies like MEGA, no effect was found for C677T MTHFR on VTE; FVL and PT20210A were confirmed to be moderate risk factors. Notably, double carriers of the two genetic variants produced an impact on VTE risk significantly increased but weaker than previously thought.

Factors associated with the development of superficial vein thrombosis in patients with varicose veins

INTRODUCTION

Superficial vein thrombosis (SVT) is a common and controversial clinical entity. Recent studies have demonstrated that SVT should be seen as a venous thromboembolism (VTE). The objective of this study was to investigate the prevalence of thrombophilia defects and to estimate the role of age, sex and body mass index (BMI) in patients with varicose veins (VVs) and SVT.

MATERIALS AND METHODS

A total of 230 patients with VVs, 128 with, and 102 without SVT underwent thrombophilia testing included factor V Leiden, prothrombin G20210A, methylenetetrahydrofolate reductase and plasminogen activator inhibitor- 1 mutations, protein C, protein S (PS), anti-thrombin III and plasminogen deficiencies and levels of A2 antiplasmin, activate protein C resistance and lupus anticoagulant. According to Clinical-Etiology-Anatomy-Pathophysiology (CEAP) classification patients were categorized in two subgroups: moderate disease (C2,3) and severe disease (C4,5,6). Age and body mass index were also assessed.

RESULTS

The prevalence of thrombophilia defects was significantly higher in patients with moderate disease and SVT (p=0.002). In the C2,3 group, SVT was associated with PS deficiency (p=0.018), obesity (p<0.001), male gender (p=0.047) and age (p<0.001). There were no significant differences in patients with severe disease.

CONCLUSIONS

Age, male sex, obesity and PS deficiency are factors associated with SVT development among patients with VVs having moderate disease (C2,3).

Association of common thrombophilias and antiphospholipid antibodies with success rate of in vitro fertilisation

Assisted reproductive technology (ART) is extensively used as a tool for pregnancy achievement in subfertile couples. Congenital and acquired thrombophilias have been suggested by some investigators to play a role in abnormal embryo implantation and placentation. The objective of this study was to assess the role of common thrombophilias in women with unexplained infertility undergoing in vitro fertilisation (IVF). We retrospectively analysed 594 women from a large healthcare maintenance organisation going through IVF and who had a thrombophilia workup, and compared them for prevalence of thrombophilia to two reference groups consisting of 637 fertile women from previous work and 17,337 women members of the same healthcare organisation with no history of venous thromboembolism. The mean age of the women at the first cycle of IVF was 30.9 years (SD: 4.1).The mean number of IVF cycles was 7.3 (SD: 5.0), and the mean fertility success rate per woman was 14.6% (SD: 19.0%). None of the common thrombophilias tested was found to be significantly associated with the number of IVF cycles or with lower fertility success rate. Rather, women who had APCR and /or factor V Leiden and lupus anticoagulant had significantly higher live birth rates (12.3% and 12.6%, respectively) in comparison to women who were tested negative (9.0% and 9.7%, respectively). Thus, hypercoagulability is not associated with failure to achieve pregnancy. These data suggest that neither screening for thrombophilia nor anticoagulant treatment is indicated in cases with unexplained reproductive failure.

C677T methylenetetrahydrofolate reductase gene polymorphism as a risk factor involved in venous thromboembolism: a population-based case-control study

The aim of the current study was to investigate the possible correlation between the C677T methylenetetrahydrofolate reductase (MTHFR) polymorphism and venous thromboembolism (VTE) in a population-based case-control study. Homocysteine (Hcy) was quantified by Abbott IMx immunoassay; screening for C677T MTHFR substitution was performed by polymerase chain reaction (PCR) and restriction analysis. The results from the two groups (440 patients and 440 controls) revealed that the frequency of T alleles and TT carriers was significantly higher in patients compared with that of the healthy controls. The plasma levels of Hcy in the VTE group (13.05±2.37 µmol/l) were significantly higher compared with those in the control group (11.94±2.03 µmol/l, P<0.001). The C677T MTHFR polymorphism is suggested to be associated with the risk for VTE. Plasma levels of Hcy were raised in individuals with the homozygous MTHFR 677TT genotype. In conclusion, the results of the current study suggest that hyperhomocysteinemia and the homozygous 677TT MTHFR genotype are risk factors for VTE.

Nitrated fibrinogen is a biomarker of oxidative stress in venous thromboembolism

The pathogenesis of venous thromboembolism (VTE) is linked to inflammation and oxidant production, although specific markers for these pathways with pathological relevance to VTE have not been explored. The coagulant protein fibrinogen is posttranslationally modified by nitric oxide-derived oxidants to nitrated fibrinogen in both acute and chronic inflammatory states. Therefore, nitrated fibrinogen may serve as a marker of inflammation and oxidative stress in VTE. To test this hypothesis we enrolled subjects (n=251) presenting with suspected VTE at the University of Pennsylvania Hospital emergency department, 50 (19.9%) of whom were positive by imaging or 90-day follow-up. Mean nitrated fibrinogen was elevated in VTE-positive (62.7 nM, 95% CI 56.6-68.8) compared to VTE-negative patients (54.2 nM, 95% CI 51.4-57.1; P<0.01). Patients in the highest quartile of nitrated fibrinogen had an increased risk of VTE compared with patients in the lowest quartile (OR 3.30; 95% CI 1.25-8.68; P<0.05). This risk persisted after univariate adjustment for age, active cancer, and recent surgery, but not after multivariate adjustment. Mean fibrinogen levels measured either by the Clauss assay or by ELISA were not different between VTE-negative and VTE-positive patients. These data indicate that nitrated fibrinogen is an oxidative risk marker in VTE, providing a novel mechanistic link between oxidant production, inflammation, and VTE.

Hypercoagulable states

Hypercoagulable states can be inherited or acquired. Inherited hypercoagulable states can be caused by a loss of function of natural anticoagulant pathways or a gain of function in procoagulant pathways. Acquired hypercoagulable risk factors include a prior history of thrombosis, obesity, pregnancy, cancer and its treatment, antiphospholipid antibody syndrome, heparin-induced thrombocytopenia, and myeloproliferative disorders. Inherited hypercoagulable states combine with acquired risk factors to establish the intrinsic risk of venous thromboembolism for each individual. Venous thromboembolism occurs when the risk exceeds a critical threshold. Often a triggering factor, such as surgery, pregnancy, or estrogen therapy, is required to increase the risk above this critical threshold.

Lower extremity venous thrombosis in patients younger than 50 years of age

Aim

Lower extremity deep venous thrombosis in the young adult is uncommon and has not been well studied in the literature. The aim of this study is to define risk factors for deep venous thrombosis among patients younger than 50 years of age, to compare them with a control group, and to suggest recommendations for the management and treatment of venous thrombosis in this particular group of patients.

Methods

From January 2003 to January 2011, 66 consecutive Lebanese patients (29 males and 37 females) younger than 50 years, diagnosed in an academic tertiary-care center with lower extremity deep venous thrombosis by color flow duplex scan, were retrospectively reviewed. Their age varied between 21 and 50 years (mean 38.7 years). The control group included 217 patients (86 males and 131 females) older than 50 years (range: 50–96 years; mean 72.9 years).

Results

The most commonly reported risk factors in the younger age group were inherited thrombophilia (46.9% compared with 13.8% in the control group; P < 0.001), pregnancy (18.2% compared with 0.5%; P < 0.001), treatment with estrogen drugs (13.6% compared with 2.3%; P = 0.001), and family history of venous thromboembolism (9.1% compared with 3.8%; P = 0.084).

Conclusion

Inherited thrombophilia is the most commonly observed risk factor among patients younger than 50 years, with a prevalence of three times more than the control group. Young adults should be screened for thrombophilia even in the presence of transient acquired risk factors. Pregnancy and treatment with estrogen drugs essentially when associated with inherited thrombophilia represent a frequent cause of venous thrombosis among young female patients. Inferior vena cava abnormalities should be excluded in young patients with spontaneous proximal venous thrombosis especially when recurrent venous thrombosis or resistance to anticoagulation are observed.

The role of homocysteine and methylenetetrahydrofolate reductase, methionine synthase, methionine synthase reductase polymorphisms in the development of cardiovascular diseases and hypertension

Cardiovascular diseases (CVDs) are the leading causes of death in the developed countries. Elevated homocysteine level is as an independent risk factor of CVDs. The C677T and A1298C variants of methylenetetrahydrofolate reductase gene (MTHFR) have been shown to influence folate and homocysteine metabolisms. However, the relationship between MTHFR polymorphisms and hyperhomocysteinemia has not been well established yet. The gene variants were also reported to be associated with CVDs. In addition, the C677T polymorphisms may play a role in the development of hypertension. Recent research evidence has suggested that MTHFR variants might be independently linked to CVDs and hypertension, because of the involvement of the MTHFR enzyme product (5-methyl-tetrahydrofolate /5-MTHF) in the regulation of endothelial functions. Further research is required to investigate the association between gene polymorphisms of folate-metabolizing enzymes and CVDs, and to identify the possible role of the relevant gene variants in the molecular pathogenesis of hyperhomocysteinemia. Orv. Hetil., 2012, 153, 445–453.

Thrombophilia testing in neonates and infants with thrombosis

In neonates and infants with idiopathic venous thrombosis (VTE) and in pediatric populations in which thromboses were associated with medical diseases, inherited thrombophilia (IT) have been described as risk factors. Follow-up data for VTE recurrence in neonates suggest a recurrence rate between 3% in provoked and 21% in idiopathic VTE. Apart from underlying medical conditions, recently reported systematic reviews on pediatric VTE have shown significant associations between factor V G1691A, factor II G20210A, and deficiencies of protein C, protein S and antithrombin, even more pronounced when combined IT were involved. Independent from the age at first VTE onset, the pooled odds ratios (OR: single IT) for VTE ranged from 2.4 for the factor II G20210A mutation to 9.4 in neonates and infants with antithrombin deficiency. The pooled OR for persistent antiphospholipid antibodies/lupus anticoagulants was 4.9 for pediatric patients with venous VTE. The factor II G20210A mutation (OR: 2.1), and deficiencies of protein C (OR: 2.4), S (OR: 3.1) and antithrombin (OR: 3.0) also played a significant role at recurrence. Based on these data, screening and treatment algorithms must be discussed.

Prevalence of Factor V Leiden G1691A, MTHFR C677T, and Prothrombin G20210A Among Asian Indian Sickle Cell Patients

The prevalence of factor V (FV) Leiden G1691A, prothrombin G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677T mutations were investigated among 90 sickle trait, 61 sickle homozygous, 75 sickle beta thalassemia, and 15 HbSD Asian Indian sickle cell patients. In all, 297 healthy controls were evaluated to compare the polymorphism frequency. The prevalence of FV Leiden heterozygous G>A were significant in the group ( P = .02), while PRT G20210A polymorphism was not seen among patients as well as controls. However, an increased frequency of the MTHFR 677 C>T genotype was seen among patients as well as controls, but this was not statistically significant ( P = .13). This suggested a low impact of inherited hypercoagulability risk factors in the pathogenesis of sickle cell disease and/or its complications.

Acquired activated protein C resistance, thrombophilia and adverse pregnancy outcomes: a study performed in an Irish cohort of pregnant women

The combination of thrombophilia and pregnancy increases the risk of thrombosis and the potential for adverse outcomes during pregnancy. The most significant common inherited risk factor for thrombophilia is activated protein C resistance (APCR), a poor anticoagulant response of APC in haemostasis, which is mainly caused by an inherited single-nucleotide polymorphism (SNP), factor V G1691A (FV Leiden) (FVL), referred as inherited APCR. Changes in the levels of coagulation factors: FV, FVIII, and FIX, and anticoagulant factors: protein S (PS) and protein C (PC) can alter APC function causing acquired APCR. Prothrombin G20210A and methylenetetrahydrofolate reductase (MTHFR) C677T are prothrombotic SNPs which in association with APCR can also increase the risk of thrombosis amongst Caucasians. In this study, a correlation between an acquired APCR phenotype and increased levels of factors V, VIII, and IX was demonstrated. Thrombophilic mutations amongst our acquired APCR pregnant women cohort are relatively common but do not appear to exert a severe undue adverse effect on pregnancy.

Pulmonary Thromboembolism Following Radio-Frequency Ablation of the Atrioventricular Node in a Patient Heterozygous for the Factor V Leiden and the Mthfr C677T Mutations

Patients who undergo radiofrequency ablation of the atrioventricular (AV) node rarely develop acute major complications. A 41-year-old Caucasian male smoker, was admitted to the Pulmology Teaching Hospital at Belgrade, Serbia, for sharp persistent chest pain, fever and fatigue following AV node radiofrequency ablation for arrhythmia. Chest X-ray showed obtuse right costo-phrenic angle and laminar atelectasis in the right lower lung lobe. The plasma D-dimer level was elevated. A perfusion lung scan showed multiple bilateral perfusion defects and multislice computed tomography showed thrombotic mass in the right pulmonary artery. Genetic analysis revealed that he was heterozygous for the prothrombin Factor V (FV) Leiden and MTHFR C677T mutations. Therapy started with intravenous heparin, followed by warfarin. He had no other episodes over a 2-year follow-up. Lifelong oral anticoagulant therapy was recommended.

Risk factors for central venous catheter thrombotic complications in children and adolescents with cancer

BACKGROUND

The use of central venous catheters (CVCs) has greatly improved the quality of care in children with cancer, yet these catheters may cause serious infectious and thrombotic complications. The aim of this prospective registry study was to assess the host and CVC-related risk factors for CVC-created thrombotic complications.

METHODS

Patients undergoing CVC insertion for chemotherapy were followed prospectively for CVC complications. At the time of enrollment, demographic, clinical, and CVC-related data, and family history of thrombosis were collected. Survival and Cox regression analyses were performed.

RESULTS

A total of 423 CVCs were inserted into 262 patients for a total of 76,540 catheter days. The incidence of CVC-related deep-vein thrombosis (DVT) was 0.13 per 1000 catheter-days (95% confidence interval [CI], 0.06-0.24). Insertion of peripherally inserted central catheters (PICCs) and insertion in an angiography suite significantly increased the risk of symptomatic CVC-related DVT. The incidence of CVC occlusion was 1.35 per 1000 catheter-days (95% CI, 1.1-1.63). Positive family history of thrombosis significantly increased the risk of CVC occlusion (hazard ratio [HR], 2.16; 95% CI, 1.2-3.8). The CVC-related risk factors were insertion of Hickman catheters, insertion in angiography suite, and proximal-tip location. Patients developing at least 1 episode of both CVC occlusion and infection had an increased risk for developing symptomatic CVC-related DVT (HR, 4.15; 95% CI, 1.2-14.4).

CONCLUSIONS

Both patient-related and CVC-related factors are associated with higher risk of symptomatic thrombotic complications. These risk factors could be used in the clinical setting and in developing future studies for CVC thromboprophylaxis.

Targeted ultrasound is the procedure of choice for detecting rudimentary branchial cysts causing jugular and subclavian vein thrombosis

The aim of this study was to facilitate the imaging diagnosis of branchial cysts leading to combined jugular and subclavian vein thrombosis during ovarian hyperstimulation syndrome (OHSS). Three women developed combined jugular and subclavian vein thrombosis following OHSS related to assisted reproductive technologies. The imaging modalities used for diagnosis were a bimode Doppler ultrasound, MRI of the neck in two women, computed tomography (CT) angiography and venography in one. Targeted ultrasound identified the rudimentary cysts in all patients, whereas CT angiography performed with contrast material failed to detect the cyst, which resembled a vessel with thrombus in the lumen. MRI performed at the same level did detect the cyst; however, MRI of the neck requires special attention using a dedicated cystic protocol at the base of the neck. Venography was performed in one patient; it demonstrated the thrombosed vein possibly with some extrinsic compression, but it could not define a cyst. Targeted ultrasound is the simplest and best imaging modality for discerning rudimentary cysts in pregnant women with OHSS who present with jugular and subclavian vein thrombosis following assisted reproductive technology. A search for the cyst at the time of OHSS is important, as early detection could decrease the risk of developing thrombosis.

Hypercoagulable states

Hypercoagulable states can be inherited or acquired. Inherited hypercoagulable states can be caused by a loss of function of natural anticoagulant pathways or a gain of function in procoagulant pathways. Acquired hypercoagulable risk factors include a prior history of thrombosis, obesity, pregnancy, cancer and its treatment, antiphospholipid antibody syndrome, heparin-induced thrombocytopenia, and myeloproliferative disorders. Inherited hypercoagulable states combine with acquired risk factors to establish the intrinsic risk of venous thromboembolism for each individual. Venous thromboembolism occurs when the risk exceeds a critical threshold. Often a triggering factor, such as surgery, pregnancy, or estrogen therapy, is required to increase the risk above this critical threshold.

Risk factors for failure of heparin thromboprophylaxis in patients with acute traumatic spinal cord injury

Venous thromboembolism (VTE) is a well-recognized complication of Acute Traumatic Spinal Cord Injury (ATSCI). Despite prophylaxis by heparins, VTE occurs in a substantial number of ATSCI patients without an obvious explanation. In this matched case-control study we examined whether thrombophilia and other risk factors are associated with failure of thromboprophylaxis. Cases and controls receiving heparin thromboprophylaxis were selected from consecutively admitted ATSCI patients. Patients who developed a new, objectively confirmed, symptomatic VTE despite prophylaxis at hospital were matched by gender, age, level and mechanism of ATSCI with 2-3 controls without VTE. Patients were interviewed about VTE risk factors and tested for factor V Leiden (FVL), prothrombin G20210A (PT), methylenetetrahydrofolate reductase C677T homozygosity (MTHFR), lupus anticoagulant, homocysteine (Hcy) and plasma factor VIII (FVIII) levels. Twenty-two patients with new VTE episodes and 64 controls were ascertained. The total number of gene alterations for MTHFR, FVL and PT or elevated levels of Hcy or FVIII was significantly more common in patients compared to controls (82% vs. 48%, p=0.006). Multiple logistic regression proved the PT mutation, a positive family history of thrombosis and elevated levels of either FVIII or Hcy to be predictors of thrombosis.

CONCLUSION

A positive family history of VTE, carriership of the prothrombin mutation and elevated FVIII or Hcy levels were significantly associated with failure to prevent VTE by heparin therapy following ATSCI. Testing for thrombophilia in patients with ATSCI and possibly a more intense thromboprophylactic regimen seem desirable but need to be verified by a prospective study.