Validation of a predictive model for identifying an increased risk for recurrence in adolescents and young adults with a first provoked thromboembolism.

BACKGROUND: To develop and validate a predictive model to determinate patients at increased risk to suffer from recurrence following a first provoked deep vein thrombosis (VTE). METHODS: Predictive variables, i.e. male sex [1 point], inherited thrombophilia (IT) status (none [0 points], single [1 point], combined variants [2 points]), blood group non-0, and age at first VTE onset were included into a risk assessment model, which was derived in 511 patients and then validated in 509 independent subjects. RESULTS: VTE recurrence risk score (maximum 4 points, range 0-3) was below two for patients scored as low-risk (LRS) and ≥2 for patients at high-risk (HRS). Within a median time of 3 years after withdrawal of anticoagulation (AC) recurrence rate in LRG (derivation) was 11.8% versus 26.0% in HRS (p < 0.001). In the validation cohort within 2.2 years the recurrence rate was 9.8% in LRS versus 30.1% in HRS (p < 0.001). In multivariable analysis adjusted for age at first VTE and blood group the recurrent risk in HRS was significantly increased compared with the LRS (derivation: hazard/95% confidence interval: 3.7/1.75-7.91; validation: 4.7/2.24-9.81; combined 5.2/1.92-13.9). Model specificity (sensitivity) was 79.0% (52.0%) in the derivation cohort compared with 78.0% (43.0%) in the validation group. In conclusion, in the prediction model presented here the risk of VTE recurrence was associated with male gender and combined ITs. Based on the negative predictive value calculated the model may identify patients with a first provoked VTE not being at risk for recurrence.

Genome-wide analysis of 944 133 individuals provides insights into the etiology of haemorrhoidal disease.

OBJECTIVE: Haemorrhoidal disease (HEM) affects a large and silently suffering fraction of the population but its aetiology, including suspected genetic predisposition, is poorly understood. We report the first genome-wide association study (GWAS) meta-analysis to identify genetic risk factors for HEM to date. DESIGN: We conducted a GWAS meta-analysis of 218 920 patients with HEM and 725 213 controls of European ancestry. Using GWAS summary statistics, we performed multiple genetic correlation analyses between HEM and other traits as well as calculated HEM polygenic risk scores (PRS) and evaluated their translational potential in independent datasets. Using functional annotation of GWAS results, we identified HEM candidate genes, which differential expression and coexpression in HEM tissues were evaluated employing RNA-seq analyses. The localisation of expressed proteins at selected loci was investigated by immunohistochemistry. RESULTS: We demonstrate modest heritability and genetic correlation of HEM with several other diseases from the GI, neuroaffective and cardiovascular domains. HEM PRS validated in 180 435 individuals from independent datasets allowed the identification of those at risk and correlated with younger age of onset and recurrent surgery. We identified 102 independent HEM risk loci harbouring genes whose expression is enriched in blood vessels and GI tissues, and in pathways associated with smooth muscles, epithelial and endothelial development and morphogenesis. Network transcriptomic analyses highlighted HEM gene coexpression modules that are relevant to the development and integrity of the musculoskeletal and epidermal systems, and the organisation of the extracellular matrix. CONCLUSION: HEM has a genetic component that predisposes to smooth muscle, epithelial and connective tissue dysfunction.

Role of prothrombin 19911 A>G polymorphism, blood group and male gender in patients with venous thromboembolism: Results of a German cohort study.

The role of the A>G polymorphism at position 19911 in the prothrombin gene (factor [F] 2 at rs3136516) as a risk factor for venous thromboembolism [VTE] is still unclear. To evaluate the presence of the F2 polymorphism in VTE patients compared to healthy blood donors and to adjust the results for common inherited thrombophilias [IT], age at onset and blood group [BG], and to calculate the risk of VTE recurrence. We investigated 1012 Caucasian patients with a diagnosis of VTE for the presence of the F2 rs3136516 polymorphism and compared these with 902 healthy blood donors. Odds ratios [OR] together with their 95% confidence intervals were calculated adjusted for F5 at rs6025, F2 at rs1799963, blood group, age and gender. In addition, we evaluated the risk of recurrent VTE during patient follow-up calculating hazard ratios [HR] together with their 95% CI. Compared with the AA wildtype, the F2 GG and AG genotypes (rs3136516) were associated with VTE (OR 1.48 and 1.45). The OR in F5 carriers compared to controls was 5.68 and 2.38 in patients with F2 (rs1799963). BG "non-O" was significantly more often diagnosed in patients compared to BG "O" (OR 2.74). VTE recurrence more often occurred in males (HR 2.3) and in carriers with combined thrombophilia (HR 2.11). Noteworthy, the rs3136516 polymorphism alone was not associated significantly with recurrence. In Caucasian patients with VTE the F2 GG/GA genotypes (rs3136516) were moderate risk factors for VTE. Recurrence was associated with male gender and combined thrombophilia.

Rare genetic variants in SMAP1, B3GAT2, and RIMS1 contribute to pediatric venous thromboembolism.

Recent genome-wide association studies (GWAS) have confirmed known risk mutations for venous thromboembolism (VTE) and identified a number of novel susceptibility loci in adults. Here we present a GWAS in 212 nuclear families with pediatric VTE followed by targeted next-generation sequencing (NGS) to identify causative mutations contributing to the association. Three single nucleotide polymorphisms (SNPs) exceeded the threshold for genome-wide significance as determined by permutation testing using 100 000 bootstrap permutations (P < 10-5). These SNPs reside in a region on chromosome 6q13 comprising the genes small ARF GAP1 (SMAP1), an ARF6 guanosine triphosphatase-activating protein that functions in clathrin-dependent endocytosis, and ß-1,3-glucoronyltransferase 2 (B3GAT2), a member of the human natural killer 1 carbohydrate pathway. Rs1304029 and rs2748331 are associated with pediatric VTE with unpermuted/permuted values of P = 1.42 × 10-6/2.0 × 10-6 and P = 6.11 × 10-6/1.8 × 10-5, respectively. Rs2748331 was replicated (P = .00719) in an independent study sample coming from our GWAS on pediatric thromboembolic stroke (combined P = 7.88 × 10-7). Subsequent targeted NGS in 24 discordant sibling pairs identified 17 nonsynonymous coding variants, of which 1 located in SMAP1 and 3 in RIMS1, a member of the RIM family of active zone proteins, are predicted as damaging by Protein Variation Effect Analyzer and/or sorting intolerant from tolerant scores. Three SNPs curtly missed statistical significance in the transmission-disequilibrium test in the full cohort (rs112439957: P = .08326, SMAP1; rs767118962: P = .08326, RIMS1; and rs41265501: P = .05778, RIMS1). In conjunction, our data provide compelling evidence for SMAP1, B3GAT2, and RIMS1 as novel susceptibility loci for pediatric VTE and warrant future functional studies to unravel the underlying molecular mechanisms leading to VTE.

In vitro analysis of platelet function in acute aneurysmal subarachnoid haemorrhage.

Platelet function might play an essential role in the pathogenesis of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid haemorrhage (SAH). Thus, impaired platelet function and disturbed primary haemostasis induced by intake of acetylsalicylic acid (ASA) might influence the rate of DCI. Primary haemostasis and platelet function can be measured with in vitro diagnosis (platelet function analyser test, PFA 100). The aim of this study is to evaluate the rate of DCI, haemorrhagic complications and the neurological outcome. Two groups were compared (patients with regular platelet function versus patients with impaired platelet function). This is a retrospective observational study. An initial cohort of 787 patients with SAH has been treated from January 2005 to September 2012. Seventy-nine patients (10%) with aneurysmal SAH, a history of ASA medication and PFA testing within the first 24 h after aneurysm rupture have been included. The overall rate of DCI in the present study was 43%. In vitro platelet function testing showed pathological primary haemostasis in 69.6%. The DCI rate was higher in patients with regular tested primary haemostasis (p = 0.02, OR = 3.16, 95%CI = [1.19; 8.83]). However, outcome assessment by mGOS did not show a significant difference between the groups. Patients with impaired primary haemostasis did not display a higher rate of haemorrhagic complications. Impairment of primary haemostasis resulting from an impairment of platelet function at an early stage after SAH might lead to a lower rate of DCI. In vitro testing of platelet function might be useful to predict the occurrence of DCI in the course.

Risk factors for symptomatic venous and arterial thromboembolism in newborns, children and adolescents - What did we learn within the last 20years?

Venous thrombosis (VTE) in children is increasingly diagnosed, as advanced medical care has increased treatment intensity of hospitalized pediatric patients. The aim of this review was to summarize the data available and to discuss the controversial issue of thrombophilia screening in the light of the pediatric data available. Follow-up data for VTE recurrence in children suggest a recurrence rate between 3% (neonates) and 21% in individuals with unprovoked VTE. Apart from underlying medical conditions, recently reported systematic reviews on pediatric VTE (70% provoked) have shown significant associations between thrombosis and presence of protein C-, protein S- and antithrombin deficiency, factor 5 (F5: rs6025), factor 2 (F2: rs1799963), even more pronounced when combined inherited thrombophilias [IT] were involved. The F2 mutation, protein C-, protein S-, and antithrombin deficiency did also play a significant role at VTE recurrence. Although we have learned more about the pathophysiology of VTE with the increased discovery of IT evidence is still lacking as to whether IT influence the clinical outcome in pediatric VTE. It still remains controversial as to whether children with VTE or offspring from thrombosis-prone families benefit from IT screening. Thus, IT testing in children should be individualized.

Health-related quality of life in children, adolescents and adults with hereditary and acquired bleeding disorders.

BACKGROUND: To better understand self-reported health-related quality-of-life (HrQoL) in children and adults with chronic hemostatic conditions compared with healthy controls. METHODS/PATIENTS/RESULTS: Group 1 consisted of 74 children/adolescents aged 8-18years with hereditary bleeding disorders (H-BD), 12 siblings and 34 peers. Group 2 consisted of 82 adult patients with hereditary/acquired bleeding disorders (H/A-BD), and group 3 of 198 patients with deep venous thrombosis (DVT) on anticoagulant therapy. Adult patients were compared to 1011 healthy blood donors. HrQoL was assessed with a 'revised KINDer Lebensqualitaetsfragebogen' (KINDL-R)-questionnaire adapted to adolescents and adults. No differences were found in multivariate analyses of self-reported HrQoL in children with H-BD. In contrast, apart from family and school-/work-related wellbeing in female patients with DVT the adult patients showed significantly lower HrQoL sub-dimensions compared to heathy control subjects. Furthermore, adults with H/A-BD disorders reported better friend-related HrQoL compared to patients with DVT, mainly due to a decreased HrQoL subscale in women on anticoagulation. CONCLUSION: In children with H-BD, HrQoL was comparable to siblings and peers. In adults with H/A-BD HrQoL was comparable to patients with DVT while healthy blood donors showed better HrQoL. The friend-related HrQoL subscale was significantly reduced in female compared to male patients.

Developmental hemostasis: A lifespan from neonates and pregnancy to the young and elderly adult in a European white population.

Absolute values of reference ranges for coagulation assays in humans vary within the entire lifespan and confirm the concept of developmental hemostasis. It is known that physiologic concentrations of coagulation factors (F) gradually increase over age: they are lower in premature infants as compared to full-term babies, healthy children or adults. Here we demonstrate in a cohort of 1011 blood donors and in a group of 193 healthy pregnant women, that the process of developmental hemostasis proceeds in adults. During the course of pregnancy F and activation markers steadily increase until delivery with a parallel decrease noticed for protein S. From adolescents, young adults to the elderly there is a further increase of F, reaching significance starting between 35 and 50years of age compared to younger subjects. Covering the entire lifespan FVIII and von-Willebrand-factor showed the lowest values in carriers of blood group "O". Apart from pregnancy differences related to gender, pill users, smoking habits or the presence of thrombophilic variants were reported. Laboratory test results should be compared to age-related reference intervals when hemostatic defects are suspected to avoid misclassifications as being "healthy", prone to "bleeding" or vice versa to "thrombosis".

Impact of high-risk thrombophilia status on recurrence among children with a first non-central-venous-catheter-associated VTE: an observational multicentre cohort study.

Deficiency of antithrombin (AT), protein C (PC) or protein S (PS) constitutes a major risk factor for venous thromboembolism (VTE). Individuals at high risk for recurrence who benefit from screening need to be identified. The primary study objective was to determine the individual recurrence risk among children with a first non-central-venous-catheter-associated VTE with respect to their thrombophilia status and to evaluate if the clinical presentation at first VTE onset differs between children with AT, PC or PS deficiency versus no thrombophilia. We calculated the absolute risk of VTE recurrence and event-free-survival adjusted for thrombophilia, age, sex and positive family VTE history in 161 consecutively enrolled paediatric VTE patients. The presence of a deficiency relative to no thrombophilia was evaluated as a potential predictor of recurrence. Predictors for recurrence were AT deficiency (hazard ratio/95% CI: 6·5/2·46-17·2) and female gender (2·6/1·1-6·35). The annual recurrence rates (95% CIs) were 5·4% (2·6-10) in AT-deficient children, 1·3% (0·3-3·8) in patients with PC deficiency, 0·7% (0·08-2·4) in the PS-deficient cohort and 0·9% (0·4-1·8) in patients with no thrombophilia. Positive family VTE history or combined thrombophilias did not predict recurrence. Given the overall annual incidence rate of recurrence of 1·5% we suggest screening for AT deficiency in children with VTE.

Impact of high risk thrombophilia status on recurrence among children and adults with VTE: An observational multicenter cohort study.

BACKGROUND: Antithrombin [AT]-, protein C [PC]- or protein S [PS]-deficiency [D] constitutes a major risk factor for venous thromboembolism [VTE]. Primary study objective was to evaluate if the clinical presentation at first VTE onset differs between children and adults and to compare the individual recurrence risk among patients with respect to age at onset and their thrombophilia status ATD, PCD or PSD. METHODS/PATIENTS/RESULTS: In 137 of 688 consecutively enrolled pediatric and adult VTE patients we calculated the absolute risk of VTE recurrence and event-free-survival adjusted for thrombophilia and positive family VTE history. At first VTE children manifested i) with a lower rate of pulmonary embolism, ii) a higher rate of cerebral vascular events or multiple VTEs, and iii) showed a higher proportion of unprovoked VTE compared to adolescents and adults. Adult patients reported more often a positive VTE history compared to younger study participants. The adjusted odds of recurrence in adults was 2.05 compared to children. CONCLUSION: At disease manifestation children and adults differ with respect to i) thrombotic locations, ii) percentage of unprovoked versus provoked VTE, and iii) different rates of positive VTE family histories. Furthermore, adults showed a two-fold increase risk of VTE recurrence compared to children.

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.

Single- and Multimarker Genome-Wide Scans Evidence Novel Genetic Risk Modifiers for Venous Thromboembolism.

Previous genome-wide association studies (GWASs) have established several susceptibility genes for venous thromboembolism (VTE) and suggested many others. However, a large proportion of the genetic variance in VTE remains unexplained. Here, we report genome-wide single- and multimarker as well as gene-level associations with VTE in 964 cases and 899 healthy controls of European ancestry. We report 19 loci at the genome-wide level of association (p ≤ 5 × 10-8). Our results add to the strong support for the association of genetic variants in F5, NME7, ABO, and FGA with VTE, and identify several loci that have not been previously associated with VTE. Altogether, our novel findings suggest that 20 susceptibility genes for VTE were newly discovered by our study. These genes may impact the production and prothrombotic functions of platelets, endothelial cells, and white and red blood cells. Moreover, the majority of these genes have been previously associated with cardiovascular diseases and/or risk factors for VTE. Future studies are warranted to validate our findings and to investigate the shared genetic architecture with susceptibility factors for other cardiovascular diseases impacting VTE risk.

End-stage renal disease and thrombophilia.

Chronic kidney disease is an established risk factor for arterial and venous thromboembolism (TE). Whereas the overall risk of TE in moderately decreased kidney function is approximately 2.5-fold higher compared to patients with normal renal function, the risk increase is 5.5-fold in patients with severe renal dysfunction. In patients with renal dysfunction and arterial thrombosis (OR: 4.9), malignancy (OR: 5.8) surgery (OR: 14.0) or thrombophilia (OR: 4.3) the risk to suffer from venous TE is higher compared to the risk associated to the baseline renal dysfunction alone. The treatment options for end-stage renal diseases include hemodialysis, peritoneal dialysis and kidney transplantation. During all treatment modalities thrombotic complications have been described, namely catheter malfunction and shunt thrombosis in patients undergoing hemodialysis in up to 25% of patients, and TE, pulmonary embolism or graft vessel thrombosis in approximately 8% of patients. The reported incidence of reno-vascular thrombosis following renal transplantation leading to hemorrhagic infarction with organ rejection or organ loss varied between 2-12%. Keeping in mind the multifactorial etiology of TE in patients with kidney dysfunction a general screening for thrombophilia in this patient group is not indicated. Selected screening on an individual patient basis should be discussed if the family history for TE is positive or the patient itself had suffered one thrombosis before the onset of the renal disease or multiple TEs during hemodialysis or post kidney transplantation in patients waiting for living donor kidney transplantation.

Bleeding issues in neonates and infants - update 2015.

The presentation of a neonate with clinical bleeding symptoms commonly causes considerable anxiety to parents and treating physicians. Since inherited coagulation disorders are rare many children with persistently abnormal coagulation screens will have an underlying bleeding disorder. Apart from emergency cases a family history including a bleeding questionnaire is mandatory asking for the onset and/or severity symptoms of hemorrhage prior to laboratory assessment. The absolute values of reference ranges for coagulation assays in neonates and children vary with analyzer and reagent systems, but confirm the concept of developmental hemostasis, showing that physiologic concentrations of coagulation proteins gradually increase and are lower in premature infants as compared to full-term babies or healthy children. The evaluation should include global screening tests and a full blood cell count to rule out thrombocytopenia. As in adults a prolonged PT in neonates reflects decreased plasma concentrations of vitamin-K-dependent factors, whereas the prolonged PTT stems from decreased plasma levels of contact factors. When initial laboratory test results reveal abnormalities, as compared to age-related values, a stepwise diagnostic approach should be followed. In the bleeding neonate or infant that has no laboratory abnormality, FXIII and alpha2-antiplasmin activity should be assessed, and when primary hemostatic defects are suspected, platelet function should be further evaluated. Treatment options of a bleeding neonate vary according to the underlying medical condition.

Role of protein S deficiency in children with venous thromboembolism. An observational international cohort study.

Venous thromboembolism [TE] is a multifactorial disease, and protein S deficiency [PSD] constitutes a major risk factor. In the present study the prevalence of PSD and the clinical presentation at TE onset in a cohort of children is reported. In 367 unselected paediatric patients with TE (age 0.1-18 years) recruited between July 1996 and December 2013, a comprehensive thrombophilia screening was performed along with recording of anamnestic data. Thirty of 367 paediatric patients (8.2 %) derived from 27 families had PSD. Mean age at first TE onset was 14.5 years (range 0.1 to 18). Thrombotic locations were cerebral veins (n=8), calf vein TE (n=3) deep veins (DVT) of the leg (n=12), DVT & pulmonary embolism (n=5) and intra-cardiac veins (n=1) or purpura fulminans (n=1). PSD co-occurred with the factor 5 mutation at rs6025 or the homozygous factor 2 susceptibility variant at rs1799963 in one case each. The Heerlen polymorphism detected in five children presented with milder PSD. In 18 patients (60 %) a concomitant risk factor for TE was identified. A second TE event within primarily healthy siblings occurred in three of 27 PSD families (11.0 %). In this cohort of children with symptomatic TE, the prevalence of PSD adjusted for family status was 7.4 %. 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.

Influence of factor 5 rs6025 and factor 2 rs1799963 mutation on inhibitor development in patients with hemophilia A--an Israeli-German multicenter database study.

OBJECTIVE: The present cohort study was performed to investigate the impact of the factor 5 rs6025 [F5] and the factor 2 rs1799963 [F2] mutations on high-titer inhibitor development [HRI] in patients with severe/moderate-severe hemophilia A [HA]. PATIENTS AND METHODS: 216 patients with F8<2% born between 1980 and 2011 were followed after initial HA diagnosis over the first 200 exposure days. The first HA patient per family who presented for diagnosis was included in the present study. RESULTS: 32 of 216 children [14.8%] tested for F5/F2 carried either the F5 or the F2 variant. HRI occurred in 14 out of 32F5/F2-carriers compared with 40 of 184 without F5/F2. Multivariate analysis adjusted for F8 genotype, treatment intensity, first-line use of plasma derived FVIII versus recombinant FVIII concentrates revealed that the presence of F5/F2 independently increases the risk of HRI development to odds [OR] of 3.4. Large deletions in the F8 gene [OR: 5.10], patients from Israel [OR: 4.0], the increase of FVIII per one IU/kgbw [OR: 1.05] and birth year [OR: 1.12] were significantly associated with the risk to develop HRI. CONCLUSION: Data presented here suggest that HRI development is of multifactorial origin and that F5 and F2 mutations may contribute to this risk.