Genetic susceptibility to venous thrombosis

Three-Dimensional Bio-Printed Tubular Tissue Using Dermal Fibroblast Cells as a New Tissue-Engineered Vascular Graft for Venous Replacement

The current study was a preliminary evaluation of the feasibility and biologic features of three-dimensionally bio-printed tissue-engineered (3D bio-printed) vascular grafts comprising dermal fibroblast spheroids for venous replacement in rats and swine. The scaffold-free tubular tissue was made by the 3D bio-printer with normal human dermal fibroblasts. The tubular tissues were implanted into the infrarenal inferior vena cava of 4 male F344-rnu/rnu athymic nude rats and the short-term patency and histologic features were analyzed. A larger 3D bio-printed swine dermal fibroblast-derived prototype of tubular tissue was implanted into the right jugular vein of a swine and patency was evaluated at 4 weeks. The short-term patency rate was 100%. Immunohistochemistry analysis showed von Willebrand factor positivity on day 2, with more limited positivity observed on the luminal surface on day 5. Although the cross-sectional area of the wall differed significantly between preimplantation and days 2 and 5, suggesting swelling of the tubular tissue wall (both p < 0.01), the luminal diameter of the tubular tissues was not significantly altered during this period. The 3D bio-printed scaffold-free tubular tissues using human dermal or swine fibroblast spheroids may produce better tissue-engineered vascular grafts for venous replacement in rats or swine.

Thrombosis-related characteristics of pregnant women with antithrombin deficiency, protein C deficiency and protein S deficiency in Japan

BACKGROUND

 We previously conducted a primary survey of pregnant women with hereditary thrombophilia based on national surveillance in Japan, but did not examine their thrombosis-related characteristics. Antithrombin (AT) deficiency, protein C (PC) deficiency and protein S (PS) deficiency are the major types of hereditary thrombophilia in Japan.

METHODS

We examined their detailed information related to thrombosis, and evaluated peripartum outcomes in comparison with control data obtained from the Japan Society of Obstetrics and Gynecology.

RESULTS

Definite or probable AT deficiency, PC deficiency and PS deficiency were observed in 80, 50, and 317 pregnancies, respectively, from 2014 to 2018 in Japan, with prevalence rates among total deliveries of 0.011%, 0.007%, 0.044%. The number of pregnancies with AT, PC and PS deficiency might have been as many as 27, 17 and 108 every year if complete answers had been provided. In the peripartum period of current pregnancies, 27.5% of women with AT deficiency, 28.0% with PC deficiency and 13.2% with PS deficiency developed thrombosis (p < 0.001 vs. control). Pregnant women with AT and PC deficiency were more susceptible to thrombosis than those with PS deficiency (P < 0.01). Of the thromboses, 92.3% occurred during pregnancy, 62.8% at less than 15 gestational weeks. The earliest onset of thrombosis was 5 gestational weeks. Prophylactic anticoagulation significantly prevented the onset of both antepartum and postpartum thrombosis (p < 0.0001). The rate of recurrent pregnancy loss in women with low PC or PS activities was significantly higher than in controls (p < 0.0001); however, it is unknown whether recurrent pregnancy loss is related to hereditary PS deficiency. There seem to have been few serious maternal or fetal/neonatal complications due to placental insufficiency related to a hypercoagulable state other than growth restriction.

CONCLUSIONS

This survey revealed the thrombosis-related characteristics of pregnant women with hereditary thrombophilia in Japan. We suggest prophylactic anticoagulation to prevent maternal or fetal/neonatal complications.

Analysis of PROS1 mutations and clinical characteristics in three Chinese families with hereditary protein S deficiency

We report three heterozygous PROS1 mutations that caused type I protein S deficiency in three unrelated Chinese families. We measured protein S activity and antigen levels for all participants, screened them for mutations in the PROS1 gene. And we employed the calibrated automated thrombin generation (CAT) method to investigate thrombin generation. Numerous bioinformatics tools were utilized to analyze the conservation, pathogenicity of mutation, and spatial structure of the protein S. Phenotyping analysis indicated that all three probands exhibited simultaneous reduced levels of PS:A, TPS:Ag, and FPS:Ag. Genetic testing revealed that proband A harbored a heterozygous c.458_458delA (p.Lys153Serfs*6) mutation in exon 5, proband B carried a heterozygous c.1687C>T (p.Gln563stop) mutation in exon 14, and proband C exhibited a heterozygous c.200A>C (p.Glu67Ala) mutation in exon 2. Bioinformatic analysis predicted that the p.Lys153Serfs*6 frameshift mutation and the p.Gln563stop nonsense mutation in the protein S were classified as "disease-causing." The identification of the novel mutation p.Lys153Serfs*6 in PROS1 enriches the Human Genome Database. Our research suggests that these three mutations (p.Lys153Serfs*6, p.Gln563stop, and p.Glu67Ala) are possibly responsible for the decreased level of protein S in the three families. Furthermore, the evidence also supports the notion that individuals who are asymptomatic but have a family history of PSD can benefit from genetic analysis of the PROS1 gene.

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.

Determination of vWF, ADAMTS-13 and Thrombospondin-1 in Venous Thromboembolism and Relating Them to the Presence of Factor V Leiden Mutation

Thrombophilia in venous thromboembolism (VTE) is multifactorial. Von Willebrand factor (vWF) plays a major role in primary hemostasis. While elevated vWF levels are well documented in VTE, findings related to its cleaving protease (ADAMTS-13) are contradicting. The aim of this study was to determine vWF, ADAMTS-13, and the multifactorial Thrombospondin-1 (TSP-1) protein levels in patients after 3-6 months following an unprovoked VTE episode. We also explored a possible association with factor V Leiden (FVL) mutation. vWF, ADAMTS-13 and TSP-1 were analyzed using ELISA kits in 60 VTE patients and 60 controls. Patients had higher levels of vWF antigen (P = .021), vWF collagen-binding activity (P = .008), and TSP-1 protein (P < .001) compared to controls. ADAMTS-13 antigen was lower in patients (P = .046) compared to controls but ADAMTS-13 activity was comparable between the two groups (P = .172). TSP-1 showed positive correlation with vWF antigen (rho = 0.303, P = .021) and negative correlation with ADAMTS-13 activity (rho = -0.244, P = .033) and ADAMTS-13 activity/vWF antigen ratio (rho = -0.348, P = .007). A significant association was found between the presence of FVL mutation and VTE (odds ratio (OR): 9.672 (95% confidence interval (CI) 2.074-45.091- P = .004), but no association was found between the mutation and the studied proteins (P > .05). There appears to be an imbalance between vWF and ADAMTS-13 in VTE patients even after 3-6 months following the onset of VTE. We report that the odds of developing VTE in carriers of FVL mutation are 9.672 times those without the mutation, but the presence of this mutation is not associated with the studied proteins.

Direct oral anticoagulants for deep vein thrombosis among patients with hereditary thrombophilia-A cohort study

OBJECTIVES

to evaluate direct oral anticoagulants (DOACs) in patients with hereditary thrombophilia and deep venous thrombosis (DVT).

METHODS

This is a retrospective observational study.

RESULTS

In total, 45 patients were treated between 01/2012 and 12/2022 (mean follow-up: 1.5 +/- 0.3 years). The most frequent thrombophilias were heterozygous V Leiden (20%), heterozygous MTHFR C677T (37.8%), heterozygous MTHFR A1298C (24.4%), and hyperhomocysteinemia (26.7%). The patients received rivaroxaban (n = 19), apixaban (n = 15), and dabigatran (n = 11). Three cases presented symptoms' recurrence without evidence of thrombosis' recurrence (two under rivaroxaban and one under apixaban; p > .05). These patients improved under parenteral anticoagulation and were further treated with dabigatran. No other event or major bleeding occurred during the follow-up. The presence of more than two factors was associated with acute recurrence of symptoms (OR = 25.9; 95% CI [1.454-461.262]; p = .026).

CONCLUSIONS

DOACs seem to be safe and efficient for patients with hereditary thrombophilia and DVT. The presence of more than two thrombophilia factors is associated with a higher risk for symptom recurrence. Although statistically non-significant, symptoms' recurrence was also observed more frequently among patients under anti-Xa inhibitors than antithrombin inhibitors. This should be verified in larger comparative studies.

Case report: Blotchy skin in a puffy neonate: is there a new association?

Introduction

Purpura fulminans in the neonatal population is a rare but potentially life-threatening condition complicated by thrombosis, resultant vital organ necrosis, and gangrene of the extremities. Considering the rapid evolution of the pathogenetic mechanism, an index of suspicion, early identification, and prompt intervention are imperative for improved outcomes. The majority of purpura fulminans cases have an infectious etiology, but it is essential to consider other congenital and acquired causes.

Case description

We present a clinical case of a female neonate to emphasize the correlation between purpura fulminans, congenital chylothorax, involvement of the PAK2 gene, and the occurrence of retinal detachment in both eyes. After draining the congenital chylothorax, the neonate developed purpura fulminans due to a loss of protein C, S, and antithrombin factors, previously not reported in the literature. The purpuric lesions resolved after the administration of fresh frozen plasma. Subsequently, no recurring purpura fulminans lesions were noted following the normalization of the antithrombotic factor levels in the serum. Subsequently, the child also developed retinal detachment in both eyes.

Whole-Exome Sequencing in a Family with an Unexplained Tendency for Venous Thromboembolism: Multicomponent Prediction of Low-Frequency Variant Deleteriousness and of Individual Protein Interaction

Whole-exome sequencing (WES) in families with an unexplained tendency for venous thromboembolism (VTE) may favor detection of low-frequency variants in genes with known contribution to hemostasis or associated with VTE-related phenotypes. WES analysis in six family members, three of whom affected by documented VTE, filtered for MAF < 0.04 in 192 candidate genes, revealed 22 heterozygous (16 missense and six synonymous) variants in patients. Functional prediction by multi-component bioinformatics tools, implemented by a database/literature search, including ClinVar annotation and QTL analysis, prioritized 12 missense variants, three of which (CRP Leu61Pro, F2 Asn514Lys and NQO1 Arg139Trp) were present in all patients, and the frequent functional variants FGB Arg478Lys and IL1A Ala114Ser. Combinations of prioritized variants in each patient were used to infer functional protein interactions. Different interaction patterns, supported by high-quality evidence, included eight proteins intertwined in the "acute phase" (CRP, F2, SERPINA1 and IL1A) and/or in the "fibrinogen complex" (CRP, F2, PLAT, THBS1, VWF and FGB) significantly enriched terms. In a wide group of candidate genes, this approach highlighted six low-frequency variants (CRP Leu61Pro, F2 Asn514Lys, SERPINA1 Arg63Cys, THBS1 Asp901Glu, VWF Arg1399His and PLAT Arg164Trp), five of which were top ranked for predicted deleteriousness, which in different combinations may contribute to disease susceptibility in members of this family.

Laboratory Evaluation of Antithrombin, Protein C, and Protein S

Thrombophilia is a complex disease process, clinically manifesting in various forms of venous thromboembolism. Although both genetic and acquired (or environmental) risks factors have been reported, the presence of a genetic defect (antithrombin [AT], protein C [PC], protein S [PS]) is considered three of the major contributing factors of thrombophilia. The presence of each of these risk factors can be established by clinical laboratory analysis; however, the clinical provider and laboratory personnel must understand the testing limitations and shortcomings associated with the assays for these factors to be able to ensure an accurate diagnosis. This article will describe the major pre-analytical, analytical, and post-analytical issues associated with the various types of assays and discuss evidence-based algorithms for analyzing AT, PC, and PS in plasma.

Testing for Factor V Leiden (FVL) and Prothrombin G20210A Genetic Variants

Laboratory testing for Factor V Leiden and Prothrombin G20210A genetic variants permits defining the increased relative risk for venous thromboembolism in selected patients. Laboratory DNA testing for these variants may be undertaken by a variety of methods, including fluorescence-based quantitative real-time PCR (qPCR). This is a rapid, simple, robust, and reliable method to identify genotypes of interest. This chapter describes the method that employs PCR amplification of the patient DNA region of interest and genotyping by allele-specific discrimination technology on a quantitative real-time PCR (qPCR) instrument.

Laboratory Evaluation of Thrombophilia

Venous thromboembolism (VTE) occurs typically in the veins of the lower extremities and/or as pulmonary embolism. There is a myriad of causes of VTE ranging from provoked causes (e.g., surgery, cancer) to unprovoked causes (e.g., inherited abnormalities) or multiple factors that combine to initiate the cause. Thrombophilia is a complex, multi-factorial disease that may result in VTE. The mechanism(s) and causes of thrombophilia are complex and not completely understood. In healthcare today, only some answers about the pathophysiology, diagnosis, and prevention of thrombophilia have been elucidated. The laboratory analysis for thrombophilia is not consistently applied, and has changed over time, but remains varied by providers and laboratories as well. Both groups must establish harmonized guidelines for patient selection and appropriate conditions for analysis of inherited and acquired risk factors. This chapter discusses the pathophysiology of thrombophilia, and evidence-based medicine guidelines discuss the optimum laboratory testing algorithms and protocols for selection and analyzing VTE patients to ensure a cost-effective use of limited resources.

Thromboembolic Disease in Haemophilic Patients Undergoing Major Orthopaedic Surgery: Is Thromboprophylaxis Mandatory?

Haemophilia is a rare genetic disorder, that results from various degrees of deficiency of coagulation factor VIII (haemophilia A), or factor IX (haemophilia B), with an X-linked transmission. The patients affected are in the majority of cases males (who inherit the affected X-chromosome from the maternal side), with rare cases of females with haemophilia (FVIII or FIX < 40 IU/dL), situations in which both X-chromosomes are affected, or one is affected, and the other one is inactive (known as carrier). The hypocoagulable state due to the deficiency of clotting factors, manifests as an excessive, recurrent tendency to bleeding, which positively correlates with plasmatic levels. Severe haemophilia results in hemarthrosis, although recent data have shown that moderate or even mild disease can lead to joint bleeding. Recurrent episodes of haemorrhages, usually affecting large joints such as knees, elbows, or ankles, lead to joint remodelling and subsequent haemophilic arthropathy, which may require arthroplasty as a last therapeutic option. Orthopaedic patients have the highest risk among all for deep vein thrombosis (DVT) and venous thromboembolism (VTE) with morbid and potentially fatal consequences. While for the rest of the population thromboprophylaxis in orthopaedic surgery is efficient, relatively safe, and widely used, for patients with haemophilia who are considered to have a low thromboembolic risk, there is great controversy. The great heterogeneity of this particular population, and the lack of clinical trials, with only case reports or observational studies, makes thromboprophylaxis in major orthopaedic surgery a tool to be used by every clinician based on experience and case particularities. This review aims to briefly summarise the latest clinical data and to offer an insight into the current recommendations that readers would find useful in daily practice.

[Cardiovascular risk factors, haemostasis and antithrombotic treatment in retinal vessel occlusion]

Venous and arterial retinal vascular occlusions are age-related disorders, generally associated with classical cardiovascular risk factors, rather than an isolated ocular disease. As affected patients often also have an increased general risk for other vascular diseases, such as ischemic stroke, an interdisciplinary clarification of cardiovascular risk factors and systemic comorbidities is essential for all patients. Extended hemostaseological investigations may be recommended in those patients who do not match the typical risk profile. Patients at a young age by the time of manifestation, without conventional risk factors as well as patients with an increased risk of developing antiphospholipid syndrome may require a selective clinical investigation including testing for thrombophilic risk factors. Recent studies have clearly demonstrated an association between coagulation and lipid metabolism disorders and the development of both retinal vein and artery occlusions in specific subgroups of patients. Therapeutic approaches to treat retinal vascular occlusions or reduce the long-term risk of recurrences with anticoagulant or antiplatelet drugs have not gained widespread acceptance. However, intravenous thrombolysis may be a valuable treatment option for central retinal artery occlusions within a short time to treatment therapeutic window. For defined disorders of the coagulation system, the administration of antithrombotic drugs to reduce the general vascular risk can be a reasonable approach. This article provides an overview of cardiovascular risk factors, the general vascular risk and the current state of knowledge on ophthalmologically relevant disorders of coagulation and lipid metabolism in patients with venous and arterial retinal vascular occlusions.

Evaluation of outcome from endovascular therapy for Budd-Chiari syndrome: a systematic review and meta-analysis

This study was performed to evaluate the outcome of endovascular intervention therapy for Budd-Chiari syndrome (BCS) and compare recanalization, transjugular intrahepatic portosystemic shunt (TIPS)/direct intrahepatic portosystemic shunt (DIPS), and combined procedure treatment. For the meta-analysis, 71 studies were identified by searching four databases. The individual studies’ samples were used to calculate a confidence interval (CI 95%), and data were pooled using a fixed-effect model and random effect model. The pooled measure and an equal-weighted average rate were calculated in all participant studies. Heterogeneity between the studies was assessed with I², and T² tests, and publication bias was estimated using Egger’s regression test. A total of 4,407 BCS patients had undergone an endovascular intervention procedure. The pooled results were 98.9% (95% CI 97.8‒98.9%) for a technical success operation, and 96.9% (95% CI 94.9‒98.9%) for a clinical success operation. The re-intervention rate after the initial intervention procedure was 18.9% (95% CI 14.7‒22.9%), and the survival rates at 1 and 5 years after the initial intervention procedure were 98.9% (95% CI 96.8‒98.9%) and 94.9% (95% CI 92.9‒96.9%), respectively. Patients receiving recanalization treatment (98%) had a better prognosis than those with a combined procedure (95.6%) and TIPS/DIPS treatment (94.5%). The systematic review and meta-analysis further solidify the role of endovascular intervention treatment in BCS as safe and effective. It maintains high technical and clinical success and long-term survival rates. The recanalization treatment had a better prognosis and outcome than the combined procedures and TIPS/DIPS treatment.

Protein S Deficiency and the Risk of Venous Thromboembolism in the Han Chinese Population

Plasma levels of the anticoagulant cofactor protein S and PROS1 mutation are reported to impart increased risk of thromboembolism in European and south east Asian populations, but the relationship is not yet documented in Han Chinese in population-based study. Therefore, we undertook a case-control study of this relationship among patients with venous thromboembolism, and probed the genetic factors contributing to low protein S deficiency. Among the 603 consecutively recruited venous thromboembolism patients, 51 (8.5%) proved to be deficient in free protein S antigen (lower than 38.6 U/dl), among whom 30 cases were identified to have a causative mutation by direct sequencing. In contrast, six cases (1.0%) of the 584 healthy controls had low free antigen levels, among whom direct sequencing confirmed disease-causing gene mutations in four controls (0.7%). After adjusting for age and gender, the odds ratio of developing venous thromboembolism in individuals with protein S deficiency based on free protein S tests was 8.1 (95% CI = 3.6–19.9, P < 0.001). Gene sequencing yielded 24 different heterozygous mutations in the 34 participants, of which 13 were newly described. 17 (50%) of the 34 mutations in our study cohort occurred in exons 12 and 13, indicating the LGR2 domain to be a hotspot mutation region for the protein. These findings are conducive to the clinical application of protein S assays for the molecular diagnosis of thrombophilia.

Epidemiological study about the mental state of patients after a pulmonary embolism or deep venous thrombosis event

Venous thromboembolism (VTE) occurs frequently and represents a serious threat to patient health. However, its effects on mental health have not been studied sufficiently. The objective of this study was to investigate whether VTE alters the patients' mental state. We gathered questionnaire data on 100 patients (59 men, 41 women; age ranging from 24 to 85 years) concerning psychological symptoms and body image. Our results show that after a VTE, patients develop psychological symptoms, some of which persist for more than 2 years. Examples of those symptoms include depression, intrusion, and increased scrutiny of the body. Intrusion (flashbacks, nightmares, and other traumatic sensations of reliving the thrombotic event) affected 69% of patients and may lead to social isolation, occasionally including loss of employment. Depression affected more than 50% of patients. Productivity typically decreases, and body functionality and feeling of health changed in 34-76% of patients. However, anxiety, disordered impulse control, and maladjustment were less frequent (40% or less), and patients' emotional attitude to their bodies (liking their bodies or being angry with their bodies, feelings of shame and attractiveness) tended not to change over time. Nevertheless, we feel it may be advisable to identify patients with relevant psychological changes after VTE by means of a short evidence-based questionnaire and to offer them psychological treatment in order to improve management and quality of life of these patients. The goal is, therefore, to develop diagnostic and therapeutic recommendations.

Risk Factors of Venous Thromboembolism in Sudanese Pregnant Women

Venous thromboembolism (VTE) is one of the major causes of pregnancy-related mortality and morbidity. This study aimed to determine the frequency of factor V Leiden (FVL) and prothrombin G20210A polymorphisms and measure the plasma levels of protein C (PC), protein S (PS) and antithrombin (AT) in pregnant women with VTE and healthy pregnant women. This prospective case-control study determined the frequencies of FVL G1691A and prothrombin G20210A polymorphisms and measured the plasma levels of PC, PS and AT in 198 pregnant women with VTE and 198 healthy pregnant women. Allele-specific polymerase chain reaction (ASPCR) was used to detect the FVL G1691A polymorphisms and prothrombin G20210A gene mutations. The FVL G1691A polymorphism and prothrombin G20210A gene mutations were detected only in pregnant women with VTE, with frequencies of 4.0 and 0.5%, respectively. The highest frequency of FVL G1691A polymorphism was observed in patients with deep vein thrombosis (DVT) and positively associated with contraceptive use and termination. Pregnant women with VTE had significantly lower levels of PC, PS and AT than those of controls. In conclusion, among the VTE cases, FVL G1691A polymorphism and PC, PS and AT deficiencies were the most common findings in patients presenting with DVT. Antithrombin deficiency was more common than PC and PS deficiencies. Contraceptive use, high body mass index (BMI) and termination correlated strongly with FVL G1691A polymorphism and PC and PS deficiencies in patients with VTE.

Peripartum management of hereditary thrombophilia: results of primary surveillance in Japan

This study investigated patients with thrombophilia and current peripartum management practices based on national surveillance in Japan. Between 2014 and 2018, antithrombin (AT), protein C (PC) and protein S (PS) deficiency were observed in 84, 67, and 443 pregnancies, respectively, with incidence rates among total deliveries at 0.012%, 0.009%, and 0.061%. The percentage of institutions that measured both antigens and AT, PC, and PS activity for the diagnosis of thrombophilia was 50.2%, and 46.9% of institutions did not perform gene analysis. Prophylactic anticoagulation therapy was used in the ante- and postpartum management of patients with AT deficiency at 67.1% and 66.3% of institutions, most commonly with 10,000 units of unfractionated heparin. Ante- and postpartum management of PC and PS deficiency was performed at 75.3% and 67.1% of institutions. Approximately half of the institutions performed peripartum prophylactic AT supplementation for AT deficiency. Low trough AT activity before supplementation was most commonly 50 ≤  < 70%, and the highest AT supplementation was 1500 ≤  < 3000 units. The number of pregnancies with AT, PC and PS deficiency might be as many as 29, 23 and 151 every year in Japan if complete answers were provided.

Thrombotic and Cardiovascular Events and Treatment Patterns Among Patients Hospitalized with COVID-19 in Japan: An Analysis of a Nationwide Medical Claims Database

Introduction

Limited data are available regarding the prevalence of thrombotic/cardiovascular disease and treatment patterns for patients with coronavirus disease 2019 (COVID-19) in Japan. In this study we describe patients hospitalized for COVID-19 in Japan.

Methods

This retrospective database study analyzed the Japan Medical Data Vision database (416 acute care hospitals) for patients hospitalized for COVID-19 during the identification period from 1 January 1 to 30 September 2020.

Results

Among 9282 eligible patients, 832 (9%) had developed thrombotic disease including myocardial infarction, ischemic stroke, deep vein thromboembolism and pulmonary embolism. Intriguingly, 171(1.8%) had two thrombotic events and 25 (0.3%) had three or four thrombotic events at the same time. The data also showed that arterial thrombotic events accounted for 77% of total thrombotic events. Anticoagulant and/or antiplatelet medication was provided to 3312 patients. Even with antithrombotic medication, 21.2% of patients suffered from thrombotic diseases.

Conclusions

Patients with COVID-19 could experience thrombotic complications in every blood vessel. Further optimization of medication is crucial for preventing thrombotic complications and improving prognosis.

Venous thoracic outlet syndrome

Venous thoracic outlet syndrome (vTOS) is a spectrum of disease caused by external compression of the subclavian vein as it passes through the costoclavicular space. Paget-Schroetter's Syndrome (PSS) or effort thrombosis is a subtype of vTOS where compression and microtrauma to subclavian vein from repetitive arm movements results in venous thrombosis. PSS or effort thrombosis mostly affects young otherwise healthy active individuals, and this further highlights the importance of this condition. Early diagnosis and aggressive early intervention aimed at complete resolution of acute symptoms and minimizing the risk of recurrence is ultimately important and increases the likelihood of the full restoration of limb function. Several noninvasive imaging techniques are currently available to confirm the initial diagnosis including Doppler ultrasound, contrast-enhanced computed tomography, and magnetic resonance imaging. Following diagnosis, multiple algorithms exist for the management of PSS and almost all require a multidisciplinary approach. Like any other condition involving the thrombosis of deep venous system, initial step in the management is anticoagulation. Catheter-directed therapies (CDT) have also a pivotal role as the initial treatment to resolve the acute thrombosis and establish venous patency. CDT combined with medical anticoagulation and surgical decompression are the components of most treatment algorithms for the management of patients suffering from PSS.

Bioengineering silk into blood vessels

The rising incidence of cardiovascular disease has increased the demand for small diameter (<6 mm) synthetic vascular grafts for use in bypass surgery. Clinically available synthetic grafts (polyethylene terephthalate and expanded polytetrafluorethylene) are incredibly strong, but also highly hydrophobic and inelastic, leading to high rates of failure when used for small diameter bypass. The poor clinical outcomes of commercial synthetic grafts in this setting have driven significant research in search of new materials that retain favourable mechanical properties but offer improved biocompatibility. Over the last several decades, silk fibroin derived from Bombyx mori silkworms has emerged as a promising biomaterial for use in vascular applications. Progress has been driven by advances in silk manufacturing practices which have allowed unprecedented control over silk strength, architecture, and the ensuing biological response. Silk can now be manufactured to mimic the mechanical properties of native arteries, rapidly recover the native endothelial cell layer lining vessels, and direct positive vascular remodelling through the regulation of local inflammatory responses. This review summarises the advances in silk purification, processing and functionalisation which have allowed the production of robust vascular grafts with promise for future clinical application.

Changes in hemostatic factors after kidney transplantation: A retrospective cohort study

Chronic kidney disease affects hemostasis in complex ways, producing both thrombotic and hemorrhagic diatheses. These changes may impact patient morbidity and mortality pre-transplantation, as well as allograft survival after kidney transplantation (KT). This study was conducted to analyze changes in hemostatic factors in the early post-KT period.We retrospectively analyzed 676 recipients of kidney allografts from December 2009 to December 2014. Patients receiving plasmapheresis pre- or post-KT, experiencing early allograft failure, or receiving anticoagulants or antiplatelet agents pre- or post-KT were excluded.Of the 367 included patients, acute (≤1 month) rejection occurred in 4.1% and delayed graft function occurred in 3.3%. Postoperative bleeding complications occurred in 7.9% of patients and thrombotic complications in 3.3%. Pre-transplantation, recipients had below normal hemoglobin, above normal d-dimer and homocysteine levels, and elevated rates of antiphospholipid antibodies. Hemoglobin increased to almost normal by postoperative day (POD) 28 (P  < .001). d-dimer increased on POD7, 14, and 28, although the values were not significantly different from pre-KT. The pattern of d-dimer changes suggested that they were a nonspecific consequence of major surgery. Homocysteine decreased to normal by POD7 (P  < .001). The percentage of patients with ≥1 prothrombotic factor was 82.0% pre-KT and only 14.2% on POD28 (P  < .001).The most of patients exhibited prothrombotic tendencies, including increased d-dimer and homocysteine, and increased prevalence of antiphospholipid antibodies before transplantation. They also had pre-transplantation anemia, suggesting a concomitant bleeding diathesis. However, most of these abnormal hemostatic factors improved or resolved after KT.

Vaccine-induced immune thrombotic thrombocytopenia after vaccination against Covid-19: A clinical dilemma for clinicians and patients

The coronavirus disease 2019 (Covid-19) pandemic has had devastating effects on public health worldwide, but the deployment of vaccines for Covid-19 protection has helped control the spread of SARS Coronavirus 2 (SARS-CoV-2) infection where they are available. The common side effects reported following Covid-19 vaccination were mostly self-restricted local reactions that resolved quickly. Nevertheless, rare vaccine-induced immune thrombotic thrombocytopenia (VITT) cases have been reported in some people being vaccinated against Covid-19. This review summarizes the thromboembolic events after Covid-19 vaccination and discusses its molecular mechanism, incidence rate, clinical manifestations and differential diagnosis. Then, a step-by-step algorithm for diagnosing such events, along with a management plan, are presented. In conclusion, considering the likeliness of acquiring severe SARS-CoV-2 infection and its subsequent morbidity and mortality, the benefits of vaccination outweigh its risks. Hence, if not already initiated, all governments should begin an effective and fast public vaccination plan to overcome this pandemic.

Clinical guidance for peripartum management of patients with hereditary thrombophilia

Hereditary thrombophilia is a condition in which individuals are susceptible to the formation of thrombi due to a hereditary deficiency in anticoagulant factors, antithrombin (AT), protein C (PC), or protein S (PS). Many Japanese thrombophilia patients have PS deficiency, especially PS p.K196E (also called as PS Tokushima), which is exclusive to the Japanese population, and thrombosis sometimes occurs during pregnancy. At present, no management guidelines for pregnancy and delivery in thrombophilia patients have been developed. The Study Group for Hereditary Thrombophilia, one of the research groups of blood coagulation abnormalities in the Research Program on Rare and Intractable Diseases supported with the Research Grants of the Ministry of Health, Labour and Welfare Science, has therefore developed this clinical guidance to provide healthcare workers with necessary information on safe pregnancy, parturition and neonatal management, adopting a format of responses to seven clinical questions (CQ). At the end of each answer, the corresponding Recommendation Level (A, B, C) is indicated.

Sport and Venous Thromboembolism

BACKGROUND

The occurrence of venous thromboembolisms (VTE) in association with sporting activity has been described but not yet systematically explored. The aim of this study was to determine the sites at which VTE occur in athletes, the accompanying features, and the special features of the symptoms and diagnosis, so that physicians can take the findings into consideration.

METHODS

A search of the literature in the databases PubMed, Web of Science, and Cochrane in accordance with the PRISMA criteria, together with a search of Google Scholar up to 29 February 2020.

RESULTS

No observational studies were identified. A total of 154 case descriptions were evaluated: 89 on upper-extremity deep vein thrombosis (DVT), 53 on lower-extremity DVT, and 12 on pulmonary embolisms with no evidence of thrombosis. Ninety-five percent of the upper-extremity DVT involved the region of the subclavian/axillary vein. Thoracic outlet syndrome (38%), hereditary thrombophilia/a family history of VTE (16%), intensive training (12%), and the use of oral contraceptives (7%) were identified as accompanying features. The upper-extremity DVT occurred mainly in male strength athletes and ball sports players. The lower-extremity DVT were located in the lower leg/knee (30%), the thigh (19 %), or occurred in combination in the lower leg-to-pelvis region (30 %). The features accompanying lower-extremity DVT were hereditary thrombophilia/a family history of VTE (30%), trauma (25%), immobilization (21%), and the use of oral contraceptives (11%). The lower-extremity DVT were found in endurance sports and ball sports. The symptoms may be obscured by sport-specific symptoms/trauma, and diagnosis is often delayed. Early D-dimer determination is useful and is complemented by diagnostic imaging.

CONCLUSION

VTE are found in association with sports. The background factors, the sites of VTE, the types of sports involved, and the accompanying features are all important to know. The symptoms may be obscured, and it may be difficult to reach the correct diagnosis. The possible presence of DVT must be borne in mind.

Reduced expression of annexin A2 is associated with impaired cell surface fibrinolysis and venous thromboembolism

Reduced plasma fibrinolysis has been identified as a potential risk factor for venous thromboembolism (VTE), but the role of cell surface fibrinolysis in VTE is unknown. The annexin A2/S100A10 complex serves as a coreceptor for plasminogen and tissue plasminogen activator (tPA), augmenting plasmin generation by 60-fold on the endothelial cell surface. Several studies in both mice and humans support the concept that A2 regulates fibrin homeostasis and intravascular thrombosis in vivo. Here, we examined A2 protein expression and function in 115 adult subjects with VTE and 87 healthy controls. Using peripheral blood mononuclear cells as a surrogate for endothelial cells, we found a 41% mean decrease in cell surface tPA-dependent fibrinolytic activity in subjects who had a positive personal and family history of VTE but tested negative for known inherited thrombophilias (ITs). A2 protein was reduced on average by 70% and messenger RNA levels by 30%, but neither decrease correlated with anticoagulant therapy. Neither cell A2 protein nor cell surface plasmin generation correlated with plasma-based clot lysis times, suggesting that the plasma and cell surface fibrinolytic systems operate independently of one another. These data suggest that reduced expression of annexin A2 protein is associated with cell surface hypofibrinolysis and may represent a novel risk factor for IT.

Proteolytic Cleavages in the VEGF Family: Generating Diversity among Angiogenic VEGFs, Essential for the Activation of Lymphangiogenic VEGFs

Simple Summary

Vascular endothelial growth factors (VEGFs) regulate the growth of blood and lymphatic vessels. Some of them induce the growth of blood vessels, and others the growth of lymphatic vessels. Blocking VEGF-A is used today to treat several types of cancer (“antiangiogenic therapy”). However, in other diseases, we would like to increase the activity of VEGFs. For example, VEGF-A could generate new blood vessels to protect from heart disease, and VEGF-C could generate new lymphatics to counteract lymphedema. Clinical trials are testing the latter concept at the moment. Because VEGF-C and VEGF-D are produced as inactive precursors, we propose that novel drugs could also target the enzymatic activation of VEGF-C and VEGF-D. However, because of the delicate balance between too much and too little vascular growth, a detailed understanding of the activation of the VEGFs is needed before such concepts can be converted into safe and efficacious therapies.

Abstract

Specific proteolytic cleavages turn on, modify, or turn off the activity of vascular endothelial growth factors (VEGFs). Proteolysis is most prominent among the lymph­angiogenic VEGF-C and VEGF-D, which are synthesized as precursors that need to undergo enzymatic removal of their C- and N-terminal propeptides before they can activate their receptors. At least five different proteases mediate the activating cleavage of VEGF-C: plasmin, ADAMTS3, prostate-specific antigen, cathepsin D, and thrombin. All of these proteases except for ADAMTS3 can also activate VEGF-D. Processing by different proteases results in distinct forms of the “mature” growth factors, which differ in affinity and receptor activation potential. The “default” VEGF-C-activating enzyme ADAMTS3 does not activate VEGF-D, and therefore, VEGF-C and VEGF-D do function in different contexts. VEGF-C itself is also regulated in different contexts by distinct proteases. During embryonic development, ADAMTS3 activates VEGF-C. The other activating proteases are likely important for non-developmental lymphangiogenesis during, e.g., tissue regeneration, inflammation, immune response, and pathological tumor-associated lymphangiogenesis. The better we understand these events at the molecular level, the greater our chances of developing successful therapies targeting VEGF-C and VEGF-D for diseases involving the lymphatics such as lymphedema or cancer.

Intracranial hypertension syndrome secondary to internal jugular vein thrombosis due to miliary cervical tuberculosis: A case report

Background:

Thrombosis of the internal jugular vein (IJV) is extremely rare, being central catheterization the most common cause. We present a case of a patient with an unusual appearance of neurological symptoms as a consequence of thrombosis of the IJV secondary to miliary tuberculosis.

Case Description:

A 30-year-old woman with disseminated tuberculosis, with multiple lymphadenopathy, axillary, cervical, mesenteric, retroperitoneal, and inguinal, presented with clinical evidence of intracranial hypertension. A diagnostic cerebral angiography was performed, which revealed an occluded left internal jugular and venous stasis in the entire cerebral venous system. The patient was treated with low-molecular-weight heparin, with which she had an adequate evolution.

Conclusion:

Tuberculosis is capable of generating a state of hypercoagulability, in addition to a mechanical compression effect due to cervical lymphadenopathy. We report an unusual clinical presentation, with intracranial involvement due to IJV thrombosis secondary to miliary tuberculosis. So far, there are no cases with a similar presentation described above.

Protein C global assay evaluation in naturally conceived vs. assisted reproduction-achieved twin pregnancies: a prospective longitudinal study

PURPOSE

Protein C global assay tests the global function of the protein C pathway, the most clinically significant anticoagulant pathway in humans. The objective of this study is to assess the difference in protein C global assay levels, throughout twin gestation, in naturally conceiving and ART-treated women.

METHODS

This is a prospective cohort longitudinal study of pregnant women with twin gestation. Protein C Global evaluation was performed on frozen blood samples. Ninety-eight women with twin pregnancy, thirty-eight naturally conceived and sixty following ART, were evaluated on four occasions: during the first, second, and third trimesters, and 6 weeks or later after delivery (baseline).

RESULTS

Protein C global assay levels were lower throughout pregnancy as compared to basal levels in both the naturally conceived and ART-conceived groups. However, protein C global assay levels were similar between the ART-conceived and naturally conceived twin pregnancies in all three trimesters. Perinatal complications were associated with decreased protein C global assay levels during the third trimester, although no difference was encountered between naturally conceived and ART-complicated twin pregnancies.

CONCLUSION

While protein C global assay levels drop during twin pregnancy, there is no difference between ART-conceived and naturally conceived gestations. Decreased levels of protein C global assay during the third trimester were similarly associated with perinatal complications in both groups. Our results imply that twin pregnancy of itself is a more dominant factor for perinatal complications as compared to other factors, such as subfertility or the exposure to ART per se.

Rivaroxaban in Recurrent Ischemic Stroke Due to Protein S Deficiency: A Case Report

Protein S deficiency is a thrombophilia associated with an increased risk of thromboembolism. Previous studies have shown its role as a predisposing factor for venous thromboembolism, but its role in recurrent arterial ischemic stroke remains uncertain. Here we report a patient with recurrent ischemic stroke due to protein S deficiency. Oral anticoagulant treatment with vitamin K antagonist (VKA) drugs is used to treat and prevent thromboembolic events caused by thrombophilia, but it has many limitations, especially in the case of recurrent thromboembolic events. Direct oral anticoagulants (DOACs) have many advantages over VKA. Previous studies have shown that they are safe in cases of thrombophilia, but they are not well studied in recurrent ischemic stroke due to protein S deficiency. In this study our patient was treated with rivaroxaban. Protein S deficiency may be a predisposing factor in recurrent ischemic stroke, and rivaroxaban can be a safe and effective treatment option. Further studies are needed to confirm our findings.

Silk fibroin vascular graft: a promising tissue-engineered scaffold material for abdominal venous system replacement

No alternative tissue-engineered vascular grafts for the abdominal venous system are reported. The present study focused on the development of new tissue-engineered vascular graft using a silk-based scaffold material for abdominal venous system replacement. A rat vein, the inferior vena cava, was replaced by a silk fibroin (SF, a biocompatible natural insoluble protein present in silk thread), tissue-engineered vascular graft (10 mm long, 3 mm diameter, n = 19, SF group). The 1 and 4 -week patency rates and histologic reactions were compared with those of expanded polytetrafluoroethylene vascular grafts (n = 10, ePTFE group). The patency rate at 1 and 4 weeks after replacement in the SF group was 100.0% and 94.7%, and that in the ePTFE group was 100.0% and 80.0%, respectively. There was no significant difference between groups (p = 0.36). Unlike the ePTFE graft, CD31-positive endothelial cells covered the whole luminal surface of the SF vascular graft at 4 weeks, indicating better endothelialization. SF vascular grafts may be a promising tissue-engineered scaffold material for abdominal venous system replacement.

Venous thromboembolism in anti-neutrophil cytoplasmic antibody-associated vasculitis: an underlying prothrombotic condition?

Objectives

We investigated the incidence and potential underlying risk factors of venous thromboembolism (VTE) in patients with AAV. We assessed haemostatic disturbances and factors that might contribute to the risk of development of VTE.

Methods

ANCA-positive AAV patients (n = 187) were included. Previously identified risk factors for VTE and current medication were retrieved from the medical records. We assessed haemostasis using different methods [endogenous thrombin potential (ETP), overall haemostatic potential (OHP), overall coagulation potential (OCP) and overall fibrinolysis potential (OFP)] in patients with active AAV (n = 19), inactive AAV (n = 15) and healthy controls (n = 15).

Results

Twenty-eight VTEs occurred in 24 patients over a total follow-up time of 1020 person-years. A majority of VTEs occurred within the first year after diagnosis. Old age (P < 0.01), ongoing prednisolone treatment and recent rituximab administration were more common in the VTE group (P < 0.05 for all). ETP and OHP were significantly increased and OFP significantly decreased in plasma from active compared with inactive AAV patients (P < 0.05, P < 0.01 and P < 0.05, respectively) and healthy controls (P < 0.001). We could not confirm previously reported risk factors for VTE development.

Conclusion

A high prevalence of VTE in AAV patients was seen within the first year after diagnosis, suggesting that disease activity contributes to development of VTE. Old age and concurrent treatment should also be taken into account when estimating VTE risk. The results also indicate disturbances in the haemostatic balance towards pro-thrombotic conditions in AAV patients, where ETP and OHP might be useful markers for identifying patients at high risk.

Recent advances in understanding, diagnosing and treating venous thrombosis

Focusing on the current state of the art, this article (a) describes recent advances in the understanding of the pathogenesis of venous thromboembolism (VTE), (b) discusses current approaches for the prevention, diagnosis and treatment of VTE, (c) outlines the role of aspirin for VTE prevention and treatment, and (d) highlights the unmet needs in VTE management and describes novel approaches to address them.

Recurrent PROC and novel PROS1 mutations in Vietnamese patients diagnosed with idiopathic deep venous thrombosis

INTRODUCTION

Genetic mutations of PROC and PROS1 are well-known risk factors for deep venous thrombosis (DVT) in the Asian population. However, the genetic profile of Vietnamese patients with DVT remains elusive. This study aimed to investigate the spectrum of genetic mutations of these two genes in Vietnamese patients diagnosed with idiopathic DVT.

MATERIALS AND METHODS

A total of 50 Vietnamese patients diagnosed with idiopathic DVT were recruited in this study. The entire coding regions of the protein C and protein S genes were amplified and directly sequenced to determine genetic alterations.

RESULTS

Four and six genetic mutations were detected in protein C and protein S genes, respectively, in 24 Vietnamese DVT patients. PROC c.565C > T (p.R189W) was the most common mutation found in 13 out of 50 patients, while the mutations of PROS1 comprised three missense and three nonsense variants which diffuse along the gene.

CONCLUSIONS

This study shows that mutations of protein C and protein S genes are prevalent in Vietnamese patients diagnosed with idiopathic DVT, and PROC c.565C > T (p.R189W) was the most common genetic alteration.

Three-factorial Genetic Thrombophilia with Recurrent Thrombotic Events in a Saudi Patient: A Case Report

Thrombophilia is caused by several genetic and acquired factors. Existence of more than one genetic factor may increase the risk of developing recurrent thrombotic events. Here, we present a case of a 48-year-old male with a known history of deep venous thrombosis and a known mutation in factor V Leiden combined with mild protein S deficiency, who presented with a painful swelling in the left leg. Moreover, the patient had a history of diabetes, dyslipidemia and obesity. Prothrombin time and platelet count were within the normal range. The international normalized ratio and activated partial thromboplastin time were 3.21 and 36.7 s, respectively. The Doppler study showed a thrombus in the saphenous vein, and complementary genetic screening investigations revealed heterozygous mutation for prothrombin (G20210A). A diagnosis of multifactorial genetic thrombophilia was established. The patient was treated with warfarin, which resulted in significant improvement in the follow-ups, and at the time of reporting this case, there were no clinical or biological signs of thrombosis. The presence of multiple hereditary and acquired thrombophilic factors is a rare clinical presentation that requires close monitoring, for which a lifelong anticoagulation therapy should be discussed based on the clinical response of the patient.

An exceptional case of severe combined inherited thrombophilia successfully treated with rivaroxaban

: We herein report the case of a young patient who presented with premature thromboembolic venous disease secondary to combined heterozygous G20210A prothrombin mutation, dual homozygosity for Factor V Leiden, and severe protein S deficiency. This association has never been reported to date and is likely to be exceptional, even in populations wherein these thrombophilia traits are more common. Long-term antithrombotic prophylaxis with rivaroxaban has proven successful in preventing clinical recurrence under prolonged treatment.

Cerebral sinovenous thrombosis in a child with ulcerative colitis: A case report

RATIONALE

Cerebral sinovenous thrombosis (CVT) associated with inflammatory bowel disease (IBD) is infrequent, but clinically nonnegligible due to its high disability and fatality rates.

PATIENT CONCERNS

A 12-year-old child with newly developed ulcerative colitis (UC) suffered from a sudden left-sided hemiparesis and numbness.

DIAGNOSES

Cerebral sinovenous thrombosis due to ulcerative colitis was diagnosed in this girl.

INTERVENTIONS

The patient was treated with blood transfusion and anticoagulation therapy. Digital subtraction angiography (DSA) and urokinase thrombolysis were implemented followed.

OUTCOMES

The patient achieved a complete recovery of limb functions and did not present any other stroke recurrences at follow-up a year later.

LESSONS

CVT in UC is a serious condition and can occur in the children and adolescents. Rapidly diagnosis of this complication of IBD and apply anticoagulant therapy early can contribute to avoiding a potentially fatal outcome.

Prophylaxis and Therapy of Venous Thrombotic Events (VTE) in Pregnancy and the Postpartum Period

Venous thromboembolisms and pulmonary embolisms are one of the main causes of morbidity and mortality in pregnancy. The increased risk of thrombotic events caused by the physiological changes during pregnancy alone does not justify any medical antithrombotic prophylaxis. However, if there are also other risk factors such as a history of thromboses, hormonal stimulation as part of fertility treatment, thrombophilia, increased age of the pregnant woman, severe obesity or predisposing concomitant illnesses, the risk of thrombosis should be re-evaluated - if possible by a coagulation specialist - and drug prophylaxis should be initiated, where applicable. Low-molecular-weight heparins (LMWH) are the standard medication for the prophylaxis and treatment of thrombotic events in pregnancy and the postpartum period. Medical thrombosis prophylaxis started during pregnancy is generally continued for about six weeks following delivery due to the risk of thrombosis which peaks during the postpartum period. The same applies to therapeutic anticoagulation after the occurrence of a thrombotic event in pregnancy; here, a minimum duration of the therapy of three months should also be adhered to. During breastfeeding, LMWH or the oral anticoagulant warfarin can be considered; neither active substance passes into breast milk.

Genotypic and phenotypic character of Chinese neonates with congenital protein C deficiency: a case report and literature review

Background

Our objective was to study the phenotype of and molecular genetic mechanisms underlying congenital protein C (PC) deficiency in Chinese neonates. We report the case of a neonate who presented 4 h after birth with purpura fulminans of the skin and thrombosis in the kidney. We also carried out a through literature review to study the genotype and phenotype, relevance, diagnosis, management, and prognosis of neonates with congenital PC deficiency in China.

Case presentation and literature review

Following a septic work-up and check of PC and protein S (PS) levels that showed PC deficiency, we investigated the patient’s and her parents’ genotypes. Our patient was found to have a plasma PC level of 0.8%. Molecular testing revealed a compound heterozygous mutation of the PROC gene: From the father, a c._262 G > T p. ASP88Tyr mutation in exon 4; from the mother, a C. 400 + 5G mutation in intron 5 that had been previously reported as likely pathogenic. Both parents were found to have heterozygous mutations for PC deficiency. In China, 5 other cases of congenital PC deficiency in the neonatal period were reported in the literature. In those cases, purpura fulminans and thrombosis were the main symptoms, and homozygous or compound heterozygous mutations of the PROC gene were identified.

Conclusion

Congenital PC deficiency should be ruled out for neonates presenting with purpura fulminans and thrombosis.

Thrombophilic risk factors in hemodialysis: Association with early vascular access occlusion and patient survival in long-term follow-up

Objective

Thrombophilic risk factors (TRFs) occur rather frequently in hemodialysis (HD) patients. However, little is known about their significance in HD patients, besides their potential impact on arteriovenous (AV) access failure, with varying results. We examined the effects of a wide variety of TRFs on both early AV fistula occlusion and survival among HD patients in long-term follow-up.

Methods

In this single-center, observational study, 70 consecutive HD patients from our dialysis center were examined with respect to shunt occlusion within the first 2 years after fistula creation and patient survival in a long-term follow-up (at least 16 years). We examined the presence of factor V, prothrombin, and MTHFR mutations using real-time fluorescence polymerase chain reaction. Furthermore, antithrombin (AT), protein C, protein S, and antiphospholipid antibodies (APL-Abs) were assessed.

Results

Among the 70 patients, 32 had MTHFR mutations, 10 had heterozygous factor V Leiden mutations, 4 had prothrombin mutations, 4 had protein S deficiency, 2 had protein C deficiency, 9 had AT deficiency, and 14 had APL-Abs. 40 patients had shunt occlusion. TRFs were associated with a significantly increased risk for shunt thrombosis (P<0.02). Kaplan–Meier analysis with a log-rank test revealed significantly shorter survival in HD patients with TRFs (P<0.02). Cox regression analysis showed that the presence of TRFs (P<0.05; hazard ratio, 1.94; 95% CI: 1.07–3.56), but not early shunt occlusion, was associated with short patient survival.

Conclusions

TRFs in hemodialysis patients have a strong impact on patient survival and early AV fistula failure; however, patient survival is not significantly affected by early shunt occlusion.

Compound heterozygous mutations identified in severe type I protein S deficiency impaired the secretion of protein S

AIMS

Hereditary protein S (PS) deficiency is one of the natural anticoagulant deficiencies causing thrombophilia. We herein described a young male with recurrent deep venous thrombosis, who was diagnosed as type I PS deficiency with compound heterozygous mutations of PROS1 gene. We aimed to analyse the relationship between the genotype and phenotype detection and investigate the pathological mechanisms of PROS1 mutations causing PS deficiency.

METHODS

Genetic analysis of PROS1 gene was carried out by direct sequencing. Thrombin generation potential and the inhibition function of thrombin generation by plasma PS were detected by thrombin generation test (TGT). The mRNA transcription level of mutant PS in vitro was measured by real-time PCR, while the protein level was evaluated by western blot and ELISA. Cellular distribution of the protein was further analysed by immunofluorescence.

RESULTS

Compound heterozygous mutations (PROS1 c.1551_1552delinsG, p.Thr518Argfs*39 and PROS1 c.1681C>T, p.Arg561Trp) were identified in the propositus, and the former one was a novel small indel mutation. TGT results showed impaired inhibition of thrombin generation with the addition of activated protein C in his parents with certain heterozygous mutations. In vitro expression study, p.Thr518Argfs*39 mutant produced truncated protein retained in the cytoplasm, while p.Arg561Trp mutant partially affected the secretion of PS. Both mutations are located in C-terminal sex hormone-binding globulin (SHBG)-like domain of PS.

CONCLUSIONS

Compound heterozygous mutations identified in the study have strong detrimental effect, causing severe type I PS deficiency in the propositus. SHBG-like domain of PS might play an important role in PS secretion system.

Acute pulmonary thromboembolism caused by factor V Leiden mutation in South Korea: A case report

RATIONALE

Although Factor V Leiden (FVL) mutation is a major cause of inherited thrombophilia in Western populations; the mutation is extremely rare in Asia.

PATIENT CONCERNS

Here we report a case of a 28-year old Korean woman admitted to our hospital with extensive pulmonary embolism.

DIAGNOSIS

She was heterozygous for FVL mutation up on evaluation, and screening for asymptomatic family members also revealed heterozygous FVL mutation for her mother.

INTERVENTIONS

Enoxaparin 1 mg/kg was initiated, followed by rivaroxaban 15 mg every 12 hours.

OUTCOMES

The patient showed improvement in both subjective dyspnea and right ventricular dysfunction and was successfully discharged after five hospital days.

LESSONS

FVL mutation screening may be considered in Asian patients with thrombophilia of uncertain etiology in the future.

Pulmonary Embolism

Venous thromboembolism (VTE) includes pulmonary embolism (PE) and deep vein thrombosis. PE is the third most common cause of cardiovascular death worldwide after stroke and heart attack. Management of PE has evolved recently with the availability of local thrombolysis; mechanical extraction devices; hemodynamic support devices, like extracorporeal membrane oxygenation; and surgical embolectomy. There has been development of multidisciplinary PE response teams nationwide to optimize the care of patients with VTE. This review describes the epidemiology of PE, discusses diagnostic strategies and current and emerging treatments for VTE, and considers post-PE follow-up care.

Review article: a multidisciplinary approach to the diagnosis and management of Budd-Chiari syndrome

BACKGROUND

Budd-Chiari syndrome (BCS) is a rare but fatal disease caused by obstruction in the hepatic venous outflow tract.

AIM

To provide an update of the pathophysiology, aetiology, diagnosis, management and follow-up of BCS.

METHODS

Analysis of recent literature by using Medline, PubMed and EMBASE databases.

RESULTS

Primary BCS is usually caused by thrombosis and is further classified into "classical BCS" type where obstruction occurs within the hepatic vein and "hepatic vena cava BCS" which involves thrombosis of the intra/suprahepatic portion of the inferior vena cava (IVC). BCS patients often have a combination of prothrombotic risk factors. Aetiology and presentation differ between Western and certain Asian countries. Myeloproliferative neoplasms are present in 35%-50% of European patients and are usually associated with the JAK2-V617F mutation. Clinical presentation is diverse and BCS should be excluded in any patient with acute or chronic liver disease. Non-invasive imaging (Doppler ultrasound, computed tomography, or magnetic resonance imaging) usually provides the diagnosis. Liver biopsy should be obtained if small vessel BCS is suspected. Stepwise management strategy includes anticoagulation, treatment of identified prothrombotic risk factors, percutaneous revascularisation and transjugular intrahepatic portosystemic stent shunt to re-establish hepatic venous drainage, and liver transplantation in unresponsive patients. This strategy provides a 5-year survival rate of nearly 90%. Long-term outcome is influenced by any underlying haematological condition and development of hepatocellular carcinoma.

CONCLUSIONS

With the advent of newer treatment strategies and improved understanding of BCS, outcomes in this rare disease have improved over the last three decades. An underlying haematological disorder can be the major determinant of outcome.

Asymmetric independence modeling identifies novel gene-environment interactions

Most genetic or environmental factors work together in determining complex disease risk. Detecting gene-environment interactions may allow us to elucidate novel and targetable molecular mechanisms on how environmental exposures modify genetic effects. Unfortunately, standard logistic regression (LR) assumes a convenient mathematical structure for the null hypothesis that however results in both poor detection power and type 1 error, and is also susceptible to missing factor, imperfect surrogate, and disease heterogeneity confounding effects. Here we describe a new baseline framework, the asymmetric independence model (AIM) in case-control studies, and provide mathematical proofs and simulation studies verifying its validity across a wide range of conditions. We show that AIM mathematically preserves the asymmetric nature of maintaining health versus acquiring a disease, unlike LR, and thus is more powerful and robust to detect synergistic interactions. We present examples from four clinically discrete domains where AIM identified interactions that were previously either inconsistent or recognized with less statistical certainty.