Thrombophilia testing in patients with portal vein thrombosis.

Portal vein thrombosis (PVT) is a rare but severe condition. Several risk factors predispose to PVT. However, it remains unclear to which degree thrombophilia contributes to the risk of PVT and whether PVT patients should be routinely referred for thrombophilia testing. The aim of the present study was to investigate the prevalence of thrombophilia in PVT patients to clarify the relevance of thrombophilia testing in PVT patients. Clinical data and results from thrombophilia investigations were systematically obtained from all PVT patients referred to Centre for Hemophilia and Thrombosis, Aarhus University Hospital, Denmark for thrombophilia testing between 1st of January 2010 and 31st of December 2018 (n = 93). The investigated thrombophilias included factor V Leiden and prothrombin G20210A mutations, deficiency of protein S, protein C and antithrombin, antiphospholipid syndrome, and increased levels of factor VIII. The prevalence of thrombophilia was compared to healthy controls obtained from previously published data on thrombophilia distribution in cohorts of the Western European adult general population. Comparing PVT patients with healthy controls, significantly increased odds of presence of lupus anticoagulant (crude odds ratio (OR) 6.2, 95% confidence interval (CI) 1.8-20.6) were found, whereas no significantly increased odds of inherited thrombophilia were demonstrated. In conclusion, routine testing for inherited thrombophilia in PVT patients does not seem indicated. However, PVT patients should still be tested for antiphospholipid antibodies because patients meeting the criteria for antiphospholipid syndrome preferentially should receive vitamin K antagonists as anticoagulant therapy.

Genetic Risk Factors in Venous Thromboembolism.

Genetic risk factors predispose to thrombophilia and play the most important etiopathogenic role in venous thromboembolism (VTE) in people younger than 50 years old. At least one inherited risk factor could be found in about half of the cases with a first episode of idiopathic VTE.Roughly, genetic risk factors are classified into two main categories: loss of function mutations (such as deficiencies of antithrombin, protein C, protein S) and gain of function mutations, (such as prothrombin mutation G20210A, factor V Leiden). A revolutionary contribution to the genetic background of VTE was brought by the achievements of the genome-wide association studies which analyze the association of a huge number of polymorphisms in large sample size.Hereditary thrombophilia testing should be done only in selected cases. The detection of hereditary thrombophilia has impact on the management of the anticoagulation in children with purpura fulminans, pregnant women at risk of VTE and may be useful in the assessment of the risk for recurrent thrombosis in patients presenting an episode of VTE at a young age (<40 years) and in cases with positive family history regarding thrombosis.

Age-specific onset and distribution of the natural anticoagulant deficiency in pediatric thromboembolism.

BACKGROUND: The early diagnosis of inherited thrombophilia in children is challenging because of the rarity and hemostatic maturation. METHODS: We explored protein C (PC), protein S (PS), and antithrombin (AT) deficiencies in 306 thromboembolic patients aged ≤20 y using the screening of plasma activity and genetic analysis. RESULTS: Reduced activities were determined in 122 patients (40%). Low PC patients were most frequently found in the lowest age group (0-2 y, 45%), while low PS or low AT patients were found in the highest age group (16-20 y; PS: 30% and AT: 20%). Genetic study was completed in 62 patients having no other causes of thromboembolism. Mutations were determined in 18 patients (8 PC, 8 PS, and 2 AT genes). Six of eight patients with PC gene mutation were found in age 0-2 y (75%), while six of eight patients with PS gene mutation were in 7-20 y. Two AT gene-mutated patients were older than 4 y. Four PC-deficient and two PS-deficient patients carried compound heterozygous mutations. All but one PC gene-mutated patient suffered from intracranial thromboembolism, while PS/AT gene-mutated patients mostly developed extracranial venous thromboembolism. CONCLUSION: Stroke in low PC infants and deep vein thrombosis in low PS/AT school age children could be targeted for genetic screening of pediatric thrombophilias.

Clinical and laboratory characteristics of children with venous thromboembolism and protein C-deficiency: an observational Israeli-German cohort study.

Venous thromboembolism [TE] is a multifactorial disease and protein C deficiency [PCD] constitutes a major risk factor. In the present study the prevalence of PCD and the clinical presentation at TE onset, including neonatal purpura fulminans, in a cohort of children are reported. In 367 unselected children (0·1-19 years) recruited between July 1996 and December 2013, a comprehensive thrombophilia screening was performed along with recording of anamnestic data. Twenty-five of 338 children (7·4%) had PCD. Mean age at first TE onset was 10 years (range 0·1-18). Leading thromboembolic manifestations were neonatal purpura fulminans (n = 5), TE of cerebral veins (n = 3), stroke (n = 2) deep veinthrombosis (DVT) of the leg (n = 10), DVT & pulmonary embolism (n = 2) and DVT & pelvic veins (n = 3). Concomitant risk factors for TE were identified in 12 patients, whereas 13 children spontaneously developed TE. A positive family history of DVT was found in 10 children. In this unselected cohort of paediatric patients with symptomatic TE the overall prevalence of PCD was 7·4%; 1·5% presented with neonatal purpura fulminans. Given its clinical implication for patients and family members, thrombophilia testing should be performed and the benefit of medical or educational interventions should be evaluated in this high-risk population.

Prevalence of thrombophilia according to age at the first manifestation of venous thromboembolism: results from the MAISTHRO registry.

Thrombophilia is a well-established risk factor for a venous thromboembolic event (VTE), and it has been proposed that hereditary thrombophilia may substantially contribute to the development of VTE in young patients. We aimed to analyse the prevalence of thrombophilia with special regard to the age of VTE manifestation. The study cohort consisted of 1490 patients (58% females) with a median age 43 years at the time of their first VTE. At least one thrombophilic disorder was identified in 50·1% of patients. The probability of detecting a hereditary thrombophilia declined significantly with advancing age (from 49·3% in patients aged 20 years and younger to 21·9% in patients over the age of 70 years; P < 0·001). This may be primarily attributed to the decreasing frequencies of the F5 R506Q (factor V Leiden) mutation and deficiencies of protein C or protein S with older age at the time of the initial VTE event. Moreover, thrombophilia was more prevalent in unprovoked compared with risk-associated VTE (57·7% vs. 47·7%; P = 0·001). The decline in the prevalence of hereditary thrombophilia with older ages supports the use of a selected thrombophilia screening strategy dependent on age and the presence or absence of additional VTE risk factors.

Clinical and genetic features of protein C deficiency in 23 unrelated Chinese patients.

In this study, we investigated the clinical and genetic features of protein C deficiency in the Chinese population. A total of 23 symptomatic patients with protein C deficiency were identified by thrombophilic assays. Detailed clinical data about the patients with respect to their personal and family history of venous thromboembolism (VTE) were collected. Mutational analysis was then performed by direct sequencing of the protein C gene (PROC) in the patients and their family members. Of the 23 patients, 30.4% (7/23) had additional risk factors, 51.2% (12/23) suffered from recurrent thrombotic episodes, and 50.0% (6/12) of the patients with recurrent thrombosis had more than one heterozygous mutation in PROC itself or combined with protein S gene (PROS). The sex distribution of male:female was 19:4 in the 23 symptomatic patients and 10:2 in the 12 recurrent patients. Almost all patients (22/23) had lower extremity deep vein thrombosis (DVT) and one had pulmonary embolism (PE) only. A total of 15 different causative mutations were identified from the 23 subjects with 6 (40.0%) of the mutations being novel. Among the mutations identified, the Arg147Trp substitution was hotspot mutation in the Chinese population with a high frequency of 43.5%. Our finding suggests that complex genotypes of PROC or combined with protein S deficiency are primarily responsible for an increased risk of recurrent VTE. Our data further provides a framework for correlating the clinical pathogenesis of protein C deficiency to ethnic backgrounds in the Chinese population.

Prevalence of inherited antithrombin, protein C, and protein S deficiencies in portal vein system thrombosis and Budd-Chiari syndrome: a systematic review and meta-analysis of observational studies.

BACKGROUND AND AIM: The prevalence of inherited antithrombin (AT), protein C (PC), and protein S (PS) deficiencies in portal vein system thrombosis (PVST) and Budd-Chiari syndrome (BCS) are substantially varied in different studies. No quantitative syntheses of these studies have been performed. A systematic review and meta-analysis were conducted to examine the prevalence of inherited AT, PC, and PS deficiencies in these patients and to compare the prevalence with healthy subjects. METHODS: PubMed, EMBASE, and Cochrane Library databases were employed to identify all studies in which inherited AT, PC, and PS deficiencies in PVST and/or BCS were evaluated by family study or gene analysis. Prevalence and odds ratios of these inherited deficiencies were pooled; heterogeneity among studies was evaluated. RESULTS: Nine studies were included in our meta-analysis. The pooled prevalence of inherited AT, PC, and PS deficiencies were 3.9%, 5.6%, and 2.6% in PVST, and 2.3%, 3.8%, and 3.0% in BCS, respectively. Heterogeneity among studies was not significant except for the analysis of inherited PC deficiency in BCS. Three studies compared the prevalence of these inherited deficiencies between PVST patients and healthy subjects. The pooled odds ratios of inherited AT, PC, and PS deficiencies for PVST patients were 8.89 (95% confidence interval [CI] 2.34-33.72, P = 0.0011), 17.63 (95% CI 1.97-158.21, P = 0.0032), and 8.00 (95% CI 1.61-39.86, P = 0.011), respectively. Only one study demonstrated that no inherited deficiency was found in both BCS patients and healthy subjects. CONCLUSIONS: Inherited AT, PC, and PS deficiencies are rare in PVST and BCS. These inherited deficiencies increase the risk of PVST.

Hereditary protein C deficiency in Indian patients with venous thrombosis.

Approximately, 4-11 % of the patients with idiopathic venous thrombosis (VT) show protein C (PC) deficiency. The molecular pathology of PC deficiency was analyzed in 102 patients; 98 healthy controls were also studied to assess the association of various polymorphisms with reduced PC levels. PROC gene mutations were detected only in 8 (7.8 %) patients with reduced PC levels. PROC promoter region CG polymorphisms showed statistically significant association with reduced PC levels (p < 0.001). PC deficiency in Indian VT patients can, thus, largely be explained by PROC gene promoter CG polymorphisms; only a small fraction of the patients show specific mutations in PROC gene.

Association of thrombophilia and polycystic ovarian syndrome in women with history of recurrent pregnancy loss.

PURPOSE: To evaluate the prevalence of thrombophilic disorders in polycystic ovarian syndrome (PCOS) women with history of recurrent pregnancy loss (RPL). MATERIALS AND METHODS: This study was carried out in 184 women with history of RPL, of which 92 of them were diagnosed with PCOS and 92 patients were without known PCOS. The prevalence of thrombophilic disorders was compared between the two mentioned groups. RESULTS: According to the findings, 70.7% of PCOS women with history of RPL had thrombophilic disorders. The prevalence of protein C deficiency was significantly higher in PCOS group compared to the non-PCOS group (21.7% vs. 10.9%, p = 0.04). There was a trend toward higher prevalence of protein S deficiency in PCOS group compared to the control group, but the difference did not reach statistical significance (23.9% vs. 13%, p = 0.05). The prevalence of other thrombophilic disorders such as antithrombin III deficiency, homocysteine elevation, antiphospholipid antibody and Factor V Leiden was comparable between groups. CONCLUSION: The prevalence of thrombophilic disorders was more common in PCOS women than the normal group. The protein C deficiency is associated with PCOS in women with history of RPL. There was a trend toward higher prevalence of protein S deficiency in PCOS women, which needs further study.

Thrombophilia among Chinese women with venous thromboembolism during pregnancy.

AIMS: To assess the prevalence of thrombophilia among Chinese women with venous thromboembolism (VTE) developed during pregnancy. METHODS: Based on information from a tertiary teaching unit, all recorded cases of deep vein thrombosis (DVT) and pulmonary embolism (PE) during pregnancy diagnosed between 1997 and 2005, were assessed for prevalence of thrombophilia. Fifty-five healthy women, who had at least one normal pregnancy but without any previous history of VTE, were recruited as controls. RESULTS: A total of 44 subjects completed thrombophilia screening, of whom 5 (11%) were confirmed to have thrombophilia [protein C (PC) deficiency (2), protein S (PS) deficiency (1), combined PC & PS deficiency (1) and antithrombin III deficiency (1)]. Homozygous 5,10-methylenetetrahydrofolate reductase (C677T) gene mutation was found in 6 (14%) subjects but not in the controls. There was no antiphospholipid syndrome, activated PC resistance, factor V Leiden or prothrombin gene mutations. CONCLUSION: In the Chinese population, PS and PC deficiencies are common thrombophilia for VTE during pregnancy and thrombophilia screening should be recommended in all pregnant women who suffer from VTE.

Thrombophilia in childhood: to test or not to test.

Inherited thrombophilia is defined as a genetically determined tendency to develop venous thromboembolism. In children, inherited thrombophilia contributes to the development of pediatric thromboembolic disease. As a consequence, pediatric hematologists are increasingly requested to test thrombophilia in pediatric patients with thrombosis or asymptomatic children from thrombophilic families. This article reviews the benefits and limitations of testing for thrombophilic disorders, for example, factor V Leiden, prothrombin mutation, and deficiencies of antithrombin, protein C, or protein S in childhood.

Protein C and/or protein S deficiency and occurrence of stent thrombosis: a hitherto unrecognized association.

OBJECTIVE: To study the prevalence of protein C and/or protein S deficiency in patients of stent thrombosis and correlate its association with the event, if any. BACKGROUND: Stent thrombosis is the Achilles heel of percutaneous coronary intervention (PCI) and has been associated with so many predisposing factors that if one analyzes all patients undergoing PCI, one or more such factors would be present in almost every patient; however, its incidence remains no more than 1-2%. We hypothesized a preexisting prothrombotic state, or tendency, in a small proportion of patients that possibly plays a key role in its occurrence. METHODS: We analyzed the prothrombotic tendency of individual patients by studying protein C and protein S levels. Thirteen patients presenting with stent thrombosis and 24 age- and sex-matched controls were studied. RESULTS: Protein S was found to be deficient in 11 of 13 patients (84.6%) of stent thrombosis and in only 4 of 24 patients (16.7%) in matched controls (P < 0.001), while protein C was found deficient in 2 of 12 patients (16.7%) of stent thrombosis, and 1 of 24 patients (4.2%) in matched controls (P = 0.25) and either protein C or protein S was deficient in 11 of 13 (84.6%) of stent thrombosis and 5 of 24 (20.8%) controls (P = <0.001). Low protein S levels were strongly associated with stent thrombosis (odds ratio 3.04, 95% confidence interval 1.34-4.7) with sensitivity 0.73 and specificity of 0.91. CONCLUSIONS: Protein S deficiency is strongly correlated to the occurrence of stent thrombosis, a fact that has hitherto not been recognized and needs further evaluation.

Protein C and protein S deficiencies: similarities and differences between two brothers playing in the same game.

Protein C (PC) and protein S (PS) are vitamin K-dependent glycoproteins that play an important role in the regulation of blood coagulation as natural anticoagulants. PC is activated by thrombin and the resulting activated PC (APC) inactivates membrane-bound activated factor VIII and factor V. The free form of PS is an important cofactor of APC. Deficiencies in these proteins lead to an increased risk of venous thromboembolism; a few reports have also associated these deficiencies with arterial diseases. The degree of risk and the prevalence of PC and PS deficiency among patients with thrombosis and in those in the general population have been examined by several population studies with conflicting results, primarily due to methodological variability. The molecular genetic background of PC and PS deficiencies is heterogeneous. Most of the mutations cause type I deficiency (quantitative disorder). Type II deficiency (dysfunctional molecule) is diagnosed in approximately 5%-15% of cases. The diagnosis of PC and PS deficiencies is challenging; functional tests are influenced by several pre-analytical and analytical factors, and the diagnosis using molecular genetics also has special difficulties. Large gene segment deletions often remain undetected by DNA sequencing methods. The presence of the PS pseudogene makes genetic diagnosis even more complicated.

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

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

Superficial venous thrombosis: role of inherited deficiency of natural anticoagulants in extension to deep veins.

AIM: Superficial venous thrombosis (SVT) has been considered for a long time a limited clinical condition of low importance, but this approach has changed in recent years, when several studies demonstrated that extension to deep veins occurs in 7.3 to 44% of patients, with high prevalence of pulmonary embolism. The aim of this study was to evaluate the prevalence of inherited deficiency of natural coagulation inhibitors in patients suffering from SVT in both normal and varicose veins, and to understand their role in extension to deep veins. METHODS: The study included 83 patients with SVT, without clinically obvious risk factors. Ultrasound examination was performed, and deficiencies of Protein C, Protein S and Antithrombin (AT) were investigated. RESULTS: In the patients where SVT occurred in normal veins, coagulation inhibitor deficiencies were 6.45% in the absence of extension and 62.5% in patients with extension to deep veins. In the patients with varicose vein SVT, the presence of these factors was less evident, but their prevalence was considerably higher in those with extension to deep veins (36.3%) than in non-extension (6.06%). CONCLUSIONS: Present data confirm the role of inherited thrombophilic states related to inhibitor deficiency, considering them as risk factors for SVT in normal veins. Furthermore, an association has been found between their presence and the progression of SVT to deep veins.

[Progression from a routine examination to a study. Having come this far, what should be done from now? A thrombosis risk factor study].

We were able to carry out a study of deep venous thrombosis (DVT) with the cooperation of clinicians. I herein describe a part of the study that I have conducted. Japanese patients with DVT were investigated regarding their incidences of antithrombin III (AT-III), protein C (PC), and protein S (PS) deficiencies, and the results were compared with those of normal subjects. We confirmed that the Japanese population has a high frequency of PC and PS deficiencies. Furthermore, we recommend that PS activity should be measured for the screening of thrombosis since type II deficiency accounted for approximately 50% of PS deficiency cases in both patients and the normal group in Japanese. We evaluated the reactivity of thrombin to TM by determining the TM-bound thrombin (TMBTh) to total thrombin generation (t-Th) ratio (TMBT ratio). We also examined whether a decreased TMBT ratio is associated with an increased risk of thrombosis. The TMBT ratio (TMBTh/t-Th) was significantly lower in patients with DVT than in control subjects. These results suggest that it is possible to evaluate the reactivity of thrombin to TM by determining the TMBT ratio, and this ratio may be a predictor of deep vein thrombosis. However, we have yet to investigate the causal mechanism.

Congenital prothrombotic disorders in children with peripheral venous and arterial thromboses.

AIMS: To evaluate the prevalence of congenital prothrombotic disorders in children with peripheral venous and arterial thromboses. METHODS: Deficiencies in antithrombin (AT), proteins C (PC) and S (PS), and increased lipoprotein (a), and the presence of factor V (FV) G1691A, prothrombin G20210A and methylenetetrahydrofolate reductase (MTHFR) mutations were investigated. RESULTS: Forty-eight patients (mean age, 3.4 years) were investigated. Of these patients, 23 had venous thrombosis, 22 had arterial thrombosis, and 3 had both. No patients had AT, PC or PS deficiency. FV G1691A mutation was present in 2 (7.6%) and 3 (12%) patients with venous and arterial thromboses, respectively. The prothrombin G20210A mutation was present in 1 (4%) patient with arterial thrombosis. Homozygous MTHFR C677T mutation was detected in 4 (18%) and 2 (9%) patients with venous and arterial thromboses, respectively. Increased lipoprotein (a) was present in 2 (10%) and 1 (4.5%) patients with venous and arterial thromboses, respectively. Regarding acquired risk factors, 79% of all thrombotic events were related to catheter usage. An underlying disease was present in 96% of the patients. CONCLUSIONS: Compared to acquired risk factors, congenital prothrombotic disorders are rarely present in children with peripheral venous and arterial thromboses. These results do not support general screening of children with venous and arterial thromboses for congenital prothrombotic disorders.

Clinical Characteristics and Outcome of Budd-Chiari Syndrome at a Tertiary Care Hospital in Pakistan.

OBJECTIVE: To determine the clinical characteristics of Budd-Chiari syndrome (BCS), its causes and outcome at a tertiary care hospital. STUDY DESIGN: An observational study. PLACE AND DURATION OF STUDY: The Aga Khan University Hospital,Karachi, from 2004 to 2014. METHODOLOGY: Aretrospective analysis of data was conducted. Apredesigned questionnaire was filled from medical records of patients with BCS. Clinical features, etiology, management and outcome was noted from 2004 to 2014. Descriptive statistics were determined. RESULTS: Forty-five patients' charts were reviewed; 26 (57.8%) were male patients. The median (IQR) age at diagnosis was 26.0 (20.5 to 34.5) years. Primary BCS was seen in 27 (60.0%) patients. The most frequent clinical features included ascites (82.2%), abdominal pain (55.6%), and hepatomegaly (31.1%). Acombined hepatic vein/inferior vena cava block was found in 25 (55.6%) patients. Out of the 28 tested patients protein C and protein S deficiencies were detected in 22 (78.6%) and 17 (60.7%) patients, respectively. Antithrombin III deficiency was detected in 14 (58.3%) of those tested patients. Anticoagulants were used in 24 (53.3%) patients. TIPS was done in 11 (24.4%) patients. Mortality was 6.7% (n=3). CONCLUSION: Congenital thrombophilia was a major causal factor. Age, clinical features, biochemistry and management are important factors in survival.

Genetic background of type I protein C deficiency in Finland.

In contrast to other populations the usually rare type II form of protein C deficiency is as common in Finland as type I deficiency. We recently reported that a single mutation explained virtually all cases of type II protein C deficiency in Finland, indicating strong founder effect. We now investigated in the same population the genetic background of type I protein C deficiency. Thirty-eight apparently unrelated families were studied. They represent the vast majority of all families with type I deficiency in Finland. A genetic defect was identified in 23 (61%) families who carried 13 different mutations. Only three of the 13 mutations have been reported in other populations. Unlike in type II deficiency, considerable heterogeneity in mutations was found in type I deficiency. Our results indicate interesting differences in mutational histories of these two different forms of protein C deficiency in Finland.