Genetic susceptibility to venous thrombosis

Budd-Chiari syndrome

Budd-Chiari syndrome (BCS) is a rare and potentially life-threatening disorder characterized by obstruction of the hepatic outflow tract at any level between the junction of the inferior vena cava with the right atrium and the small hepatic veins. In the West, BCS is a rare hepatic manifestation of one or more underlying prothrombotic risk factors. The most common underlying prothrombotic risk factor is a myeloproliferative disorder, although it is now recognized that almost half of patients have multiple underlying prothrombotic risk factors. Clinical manifestations can be diverse, making BCS a possible differential diagnosis of many acute and chronic liver diseases. The index of suspicion should be very low if there is a known underlying prothrombotic risk factor and new onset of liver disease. Doppler ultrasound is sufficient for confirming the diagnosis, although tomographic imaging (computed tomography (CT) or magnetic resonance imaging (MRI)) is often necessary for further treatment and discussion with a multidisciplinary team. Anticoagulation is the cornerstone of the treatment. Despite the use of anticoagulation, the majority of patients need additional (more invasive) treatment strategies. Algorithms consisting of local angioplasty, TIPS and liver transplantation have been proposed, with treatment choice dictated by a lack of response to a less-invasive treatment regimen. The application of these treatment strategies allows for a five-year survival rate of 90%. In the long term the disease course of BCS can sometimes be complicated by recurrence, progression of the underlying myeloproliferative disorder, or development of post-transplant lymphoma in transplant patients.

Factor V Leiden, Prothrombin and MTHFR Mutation in Patients with Preeclamsia, Intrauterine Growth Restriction and Placental Abruption

BACKGROUND

Factor V Leiden, Prothrombin and MTHFR gene mutation, could have an influence in pregnancy with adverse outcome Preeclamsia, IUGR and Placental abruption.

AIM

The aim of this study is to investigate the presence of above mentioned inherited thrombophilias and its statistical significance, distribution among the complicated and normal pregnancy, and relative risk for carrier of mutation to develop preeclampsia, IUGR and placental abruption.

MATERIAL AND METHODS

Prospective cohort study is implemented at University Clinic for Obstetric and Gynecology in Skopje, Republic of Macedonia. The study included 109 delivered patients: 40 with preeclapmsia, 22 with IUGR, 17 with placental abruption and 30 as control group with normal pregnancy. The amount of 3 ml venous blood has been used for detection of these point mutations using ThromboStrip -Opegen, QIAGEN kit manufactured for thrombotic risk.

RESULTS

The highest frequency was found: in the group with preeclampsia 35% were MTHFR homozygous, IUGR -MTHFR heterozygous 45%, Placental abruption- 52.9% MTHFR heterozygous, and in the control group without thrombophilia 56.7%. There were combined thrombophilia in 3 patients. There aren`t statistical significance in presence of thrombophilia among groups (p > 0.05). Statistical significance (p < 0.05) was found between carriers of MTHFR homozygous in preeclampsia and group with placental abruption and control group. Relative risk in IUGR group for MTHFR homozygous was 5.54 (1.37

CONCLUSION

The presence of mutation MTHFR homozygous could increase the risk for development of IUGR and mutation of Factor V Leiden for placental abruption. Further investigations with more patients are warranted.

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Key Words

• IUGR
• MTHFR
• factor V Leiden
• placental abruption
• preeclampsia
• prothrombin

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MESH Headings Collapse

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Affiliation(s)

Vesna Livrinova University Clinic for Obstetrics and Gynecology, Faculty of Medicine, Ss. Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia
Marija Hadzi Lega University Clinic for Obstetrics and Gynecology, Faculty of Medicine, Ss. Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia
Anita Hristova Dimcheva Institute for Transfusion Medicine, Faculty of Medicine, Ss. Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia
Igor Samardziski University Clinic for Obstetrics and Gynecology, Faculty of Medicine, Ss. Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia
Rozalinda Isjanovska Institute for Epidemiology and Medical Biostatistics, Faculty of Medicine, Ss. Cyril and Methodius University of Skopje, Skopje, Republic of Macedonia

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Genetic risk factors in patients with deep venous thrombosis, a retrospective case control study on Iranian population

Background

Venous thromboembolism (VTE) could be manifested as deep venous thrombosis (DVT) or pulmonary embolism (PE). DVT is usually the more common manifestation and is usually formation of a thrombus in the deep veins of lower extremities. DVT could occur without known underlying cause (idiopathic thrombosis) which could be a consequence of an inherited underlying risk factor or could be a consequence of provoking events, such as trauma, surgery or acute illness (provoked thrombosis). Our aim in this study was to assess the impact of some previously reported genetic risk factors including, methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, plasminogen activator inhibitor-1(PAI-1) 4G/5G, prothrombin 20210 and FV Leiden on occurrence of DVT in a population of Iranian patients.

Methods

This long-term study was conducted on 182 patients with DVT and also 250 age and sex matched healthy subjects as control group. The diagnosis of DVT was based on patient’s history, clinical findings, D-dimer test, and confirmed by Doppler ultrasonography. After confirmation of DVT, both groups were assessed for the five mentioned mutations. The relationship between mutations and predisposition to DVT was calculated by using logistic regression and expressed as an OR with a 95 % confidence interval (CI).

Results

Our results revealed that FV Leiden (OR 6.7; 95 % CI = 2.2 to 20.3; P = 0.001), MTHFR C677T (OR 6.0; 95 % CI = 2.2 to 16.4; P < 0.001), MTHFR A1298C (OR 8.3; 95 % CI = 4.4 to 15.8; P < 0.001), and PAI-1 4G/5G (OR 3.8; 95 % CI = 2.1 to 7.2; P < 0.001) mutations were all significantly associated with an increased risk of DVT. Prothrombin 20210 was found in none of the patients and controls.

Conclusion

Our findings suggest that genetic risk factors have a contributory role on occurrence of DVT.

Ethnic diversity in the genetics of venous thromboembolism

Genetic susceptibility is considered as a crucial factor for the development of venous thromboembolism (VTE). Epidemiologic and genetic studies have revealed clear disparities in the incidence of VTE and the distribution of genetic factors for VTE in populations stratified by ethnicity worldwide. While gain-of-function polymorphisms in the procoagulant genes are common inherited factors in European-origin populations, the most prevalent molecular basis for venous thrombosis in Asians is confirmed to be dysfunctional variants in the anticoagulant genes. With the breakthrough of genomic technologies, a set of novel common alleles and rare mutations associated with VTE have also been identified, in different ethnic groups. Several putative pathways contributing to the pathogenesis of thrombophilia in populations of African-ancestry are largely unknown, as current knowledge of hereditary and acquired risk factors do not fully explain the highest risk of VTE in Black groups. In-depth studies across diverse ethnic populations are needed to unravel the whole genetics of VTE, which will help developing individual risk prediction models and strategies to minimise VTE in all populations.

Diagnostic ramifications of ocular vascular occlusion as a first thrombotic event associated with factor V Leiden and prothrombin gene heterozygosity

AIM

This study aimed to assess the diagnostic ramifications of vascular occlusion of the ocular vein and artery as a first thrombotic event associated with factor V Leiden (FVL) and/or prothrombin gene (PTG) heterozygosity.

METHODS

Patients with ocular vein (n=191) and artery (n=74) occlusion, free of cardioembolic etiologies, were sequentially referred from vitreoretinal specialists for measurement of thrombophilia-hypofibrinolysis and compared to 110 healthy normal controls.

RESULTS

Of the 265 patients, 29 (11%; 17 women, 12 men) of all referred ocular vascular occlusion (OVO) cases were found to be heterozygous for FVL and/or PTG, including 16 with FVL, 12 with PTG, and 1 with both. Of the 29 cases, 16 had central retinal vein occlusion (CRVO), 2 branch retinal vein occlusion (BRVO), 5 nonarteritic anterior ischemic optic neuropathy (NA-AION), 3 retinal artery occlusion (RAO), 2 amaurosis fugax (AF), and 1 had both CRVO and RAO. Of the 16 FVL cases, 15 (94%) had OVO as a first thrombotic event without prior deep venous thrombosis (DVT) or pulmonary embolism (PE); 6 (38%) also had other thrombotic events, including recurrent miscarriage, osteonecrosis, ischemic stroke, and/or ischemic colitis; and 5 (31%) had immediate family members with previous venous thromboembolism (VTE). Of the 12 PTG cases, 9 (75%) had OVO as a first thrombotic event, 5 (42%) experienced VTE other than DVT or PE, and 6 (50%) had immediate family members with VTE. In one patient with both FVL and PTG, DVT occurred before BRVO. Of the 17 women with FVL and/or PTG mutations, 7 (41%) experienced ≥1 miscarriage, 6 (35%) were on estrogen therapy, and 1 (6%) was on clomiphene.

CONCLUSION

Of the 265 patients with OVO, 29 (11%) had FVL and/or PTG, and 83% of these 29 cases presented with OVO as their first thrombotic event. By diagnosing thrombophilia as an etiology for OVO, the ophthalmologist opens a window to family screening and preventive therapy.

Stroke Recurrence and its Prevention in Patients with Patent Foramen Ovale

BACKGROUND

It is unclear whether medical or invasive (surgical or catheter interventional) treatment is preferable to prevent recurrence of cerebral ischemia in patients with patent foramen ovale (PFO) as the suspected cause of stroke and what the role of concomitant risk factors is in stroke recurrence.

METHODS

Over a period of ten years, 124 patients (mean age 51 +/- 15 years) with cryptogenic cerebral ischemia and PFO were included into the study and prospectively followed over a mean of 52 +/- 32 months. Of these, 83 were treated medically, 34 underwent transcatheter closure, and seven had surgical closure of the foramen. Of the medically treated patients, 11 stopped medication during follow-up. Recurrent ischemic events and risk factors for recurrence were analyzed.

RESULTS

Annual stroke recurrence rates were generally low and comparable in catheter and medically treated patients, and in patients who had stopped medication (2.9%/2.1%2.2%/year). Patients suffering from recurrence after transcatheter closure (n = 2) both had residual shunts. No stroke recurrence was observed in the few surgically treated patients. An atrial septal aneurysm was not a predictor of recurrent or multiple strokes (p > 0.05, OR = 0.31, and OR = 0.74). Large shunts and a history of previous ischemic events were considerably more frequent in patients with recurrent strokes (p < 0.05, OR = 5.0, and OR = 4.4). Pulmonary embolism and case fatality rates were significantly higher in patients with stroke recurrence (p < 0.001, and p < 0.01).

CONCLUSIONS

The absolute risk of recurrent cerebrovascular events in patients with PFO receiving medical or catheter interventional therapy is low. The small group of untreated patients had a comparably low rate of stroke recurrences. Previous ischemic events and shunt size were risk factors in this observational study. Given conflicting findings across multiple studies, enrollment into a randomized controlled trial would be the optimal choice.

Varicose vein trauma: a risk for pulmonary embolism

Pulmonary embolism (PE) is a deceptive condition which is often incorrectly diagnosed leading to high morbidity and mortality. We present a case where symptoms were localised to different areas of the body starting with post-traumatic pain over lower extremity varicosities that migrated sequentially over a month to the knee, hip, back, abdomen and chest finally presenting as syncope. Despite a low pre-test clinical probability, a very high index of suspicion led to a timely diagnosis of a massive bilateral PE that eventually caused a troponin leak. The aetiology is highly suspicious of a thrombus which originated in the veins of the leg due to trauma over varicose veins.The case described here exemplifies the importance of considering trauma to varicosities as a risk factor for embolism when the clinical picture is concerning but other signs and symptoms of PE are not apparent.

Study of associated genetic variants in Indian subjects reveals the basis of ethnicity related differences in susceptibility to venous thromboembolism

The genetic variants linked with the susceptibility of individuals to VTE are well known; however, the studies explaining the ethnicity based difference in susceptibility to VTE are limited. Present study assesses mutations in six candidate genes contributing to the etiology of VTE in Indian subjects. The study comprised 93 VTE patients and 102 healthy controls. A PCR-RFLP based analysis was performed for nine mutations in the following genes associated with VTE: favtor V Leiden (FVL), prothrombin, tissue factor pathway inhibitor (TFPI), fibrinogen-beta, plasminogen activator inhibitor 1 (PAI-1), and methylene tetrahydrofolatereductase (MTHFR). All the subjects were found to be monomorphic for FVL 1691G/A, prothrombin 20210G/A and TFPI −536C/T mutations. The mutation in the MTHFR gene (677C/T) was observed only in patients. Contrarily, higher frequency of mutation in the PAI-1 −844G/A and the fibrinogen-β −455G/A was observed in controls in comparison to the patients. This study suggests that the PAI-1 −844G/A and fibrinogen-β −455G/A could be protective variants against VTE in Indians. While MTHFR 677C/T mutation was found to be associated, in contrast to other populations, the established genetic variants FVL 1691G/A, prothrombin 20210G/A, and TFPI −536C/T may not be associated with VTE in Indians thus revealing the basis of ethnicity related differences in susceptibility of Indians to VTE.

No increased venous thromboembolism risk in Asian breast cancer patients receiving adjuvant tamoxifen

Tamoxifen is an effective endocrine treatment for early breast cancer (EBC) but increases the risk of venous thromboembolism. Whether Asian EBC patients (pts) bear the same risk when treated with adjuvant tamoxifen is uncertain. EBC pts diagnosed between 2004 and 2009 were selected from a population database in Taiwan. The pts were followed up from the index date to December 31, 2011 to collect events of deep vein thrombosis (DVT) and pulmonary embolism (PE). Cumulative incidence rates and hazard ratios (HRs) were used to compare the risk between pts treated with and without tamoxifen. In addition, comorbidities were included in an adjusted model of the risk of DVT and PE. A total of 28,029 EBC pts, including 17,843 (63.8 %) in the tamoxifen group and 10,155 (36.2 %) in the nontamoxifen group, were analyzed. The 7-year cumulative incidence rates for DVT and PE were 2.58 and 0.32 % in the tamoxifen group and 2.51 and 0.32 % in the nontamoxifen group (P = 0.92 for DVT, P = 0. 65 for PE), respectively. The HR for the nonadjusted and adjusted models showed no differences in DVT and PE risks between the tamoxifen and nontamoxifen groups. The uterine cancer risk was significantly increased in the pts receiving tamoxifen (adjusted HR = 2.79, P < 0.001), suggesting tamoxifen compliance. The risks of developing DVT and PE are not increased in Asian EBC pts receiving adjuvant tamoxifen. Ethnicity differences should be considered when discussing optimal endocrine treatments with EBC pts.

The role of hemostasis in infective endocarditis

Infective endocarditis (IE) is a thromboinflammatory disease of the endocardium, with pathophysiology mostly the result of the interplay between microorganisms and modifiers of the hemostasis system. In this setting, the evidence gathered so far warrants a more systematic appraisal. In this review article, experimental and clinical data on the role of hemostasis in IE are summarized. Starting from the current pathogenetic model of IE, we discuss the dual role of platelets in this condition, the microbial interaction with the hemostasis system, also describing nonspecific hemostasis changes during sepsis. We finally propose our hypothesis of thrombophilia as a possible trigger of IE, highlighting the challenges that the study of hemostasis in IE presents. The role of hemostasis in IE appears to be an exciting field of research. The activity of the hemostasis system is highly relevant in terms of susceptibility, progression, and treatment of IE. Pharmacologic modulation of hemostasis before and after IE onset is possible and represents still a largely unexplored area of study.

The Prevalence of the Prothrombin (F2) 20210G>A Mutation in a Cohort of Sri Lankan Patients with Thromboembolic Disorders

Prothrombin (F2) 20210G>A [rs1799963 G>A] mutation is a genetic variant which predisposes to inherited thrombophilia. Highest prevalence of this rare mutation has been reported among Caucasian and Mediterranean populations with thrombophilic conditions compared to healthy controls. It is absent or occurs in a very low frequency in both thrombophilic patients and healthy controls of most South Asian populations. A previous study has demonstrated that the mutant allele is absent among Sri Lankan healthy controls. This study was conducted to determine the prevalence of the F2 20210G>A mutation among Sri Lankan patients with thrombo-embolic disorders. F2 20210G>A mutation analysis was carried out on 825 patients. These included 374 with arterial thromboembolic disorders, 303 with venous thromboembolic disorders (VTE) and 148 with pregnancy related complications. Genotyping was done using polymerase chain reaction followed by restriction fragment length polymorphism. The overall prevalence of the individuals detected with the mutation was 0.8 % (7/825) with a mutant allele frequency of 0.4 % (7/1,650), and all were heterozygotes. Further classification according to the types of thrombotic events showed a prevalence of 0.5 % (2/374), 1.3 % (4/303), and 0.7 % (1/148) respectively, in the three groups with arterial thrombosis, VTE and pregnancy complications. The respective mutant allele frequencies in the three different groups were 0.3 % (2/748), 0.7 % (4/606) and 0.3 % (1/296). Although these figures are lower than that of Caucasian and Mediterranean populations, they are relatively higher compared to other South Asian populations. Therefore, the F2 20210G>A mutant allele is not entirely absent among Sri Lankan patients with thrombo-embolic disorders.

Evaluation of GenoFlow Thrombophilia Array Test Kit in its detection of mutations in Factor V Leiden (G1691A), prothrombin G20210A, MTHFR C677T and A1298C in blood samples from 113 Turkish female patients

Thrombophilia is a heritable blood disease characterized by an increased tendency to form abnormal blood clots that can block blood vessels. In obstetrics and gynecology, it has been shown by a number of reports that a proportion of recurrent miscarriages involve thrombophilia-related mutations, in particular, Factor V G1691A, prothrombin G20210A, and MTHFR C677T and A1298C. In this study, we examined the frequency of these four mutations in 113 female Turkish patients who had prior complications in pregnancy, using the DiagCor GenoFlow Thrombophilia Array Test kit. Heterozygous MTHFR C677T and A1298C mutations were detected in 46% of the patients, and among these patients, 60% of them carried double heterozygous mutations. In contrast, the heterozygous Factor V G1691A and prothrombin G20210A were detected only in a smaller number of patients, respectively, 13% and 3%. The GenoFlow kit demonstrated 100% concordance with results from Sanger sequencing, which can be translated into sensitivity and specificity both at 100% within this series of patients.

Massive exploration of perturbed conditions of the blood coagulation cascade through GPU parallelization

The introduction of general-purpose Graphics Processing Units (GPUs) is boosting scientific applications in Bioinformatics, Systems Biology, and Computational Biology. In these fields, the use of high-performance computing solutions is motivated by the need of performing large numbers of in silico analysis to study the behavior of biological systems in different conditions, which necessitate a computing power that usually overtakes the capability of standard desktop computers. In this work we present coagSODA, a CUDA-powered computational tool that was purposely developed for the analysis of a large mechanistic model of the blood coagulation cascade (BCC), defined according to both mass-action kinetics and Hill functions. coagSODA allows the execution of parallel simulations of the dynamics of the BCC by automatically deriving the system of ordinary differential equations and then exploiting the numerical integration algorithm LSODA. We present the biological results achieved with a massive exploration of perturbed conditions of the BCC, carried out with one-dimensional and bi-dimensional parameter sweep analysis, and show that GPU-accelerated parallel simulations of this model can increase the computational performances up to a 181× speedup compared to the corresponding sequential simulations.

Prevalence of asymptomatic lower limb venous thrombosis in infertile women with thrombophilic disorders

OBJECTIVE

We sought to assess the prevalence of asymptomatic venous thrombosis in infertile women with thrombophilic disorders (TDs).

METHODS AND RESULTS

A total of 73 infertile women with TDs underwent duplex ultrasound scan to evaluate superficial and deep venous circulation of lower limbs. A control group of 35 infertile women without TDs was included. A single TD was found in 13 (17.8%) subjects, and 40 (54.8%) women presented a combined defect (more than three alterations). No residual mural thrombosis (RT) was noted in any deep veins. We found RT in 48 (65.8%) patients of TD group, while no RT was found in the control group (p < 0.0001). None of the clinical and prothrombotic factors were predictors of RT (all p > 0.20), and frequency of TD did not correlate with multi-vessel RT (p = 0.252).

CONCLUSIONS

No signs of deep vein thrombosis but high prevalence of superficial RT is present in infertile women with TDs. Further studies are needed to assess the prognostic value of our findings.

Family history unawareness of blood clot risk: links to misdiagnoses and illness uncertainties in personal and expert realms

The difficulty of diagnosing blood clots makes salient the question, "What role does family history awareness have for guiding lay and expert actions?" The authors examine the in-depth life reflection interviews of 20 women who experienced a first venous blood clot between the ages of 18 and 50 years, identifying causal attributions the women made for thrombosis after the event. Twelve participants described an understanding of the cascade of events linked to thrombosis, revealing that there is seldom a single cause. The other eight identified belief in a single determining cause for their thrombosis. The authors reflect on the symptoms the women experienced during the course of the clotting event, patterns of care that they executed to self-manage their blood clot, and their misdiagnoses associated with symptoms and care. The women recalled the patterns of care received through formal health care systems and the reported misdiagnoses linked to these interactions. The recollections reveal that the subtle nature of venous blood clot symptoms contributes to lay and expert misdiagnoses. Use of antibiotics and pain killers in the wake of misdiagnosis masks symptoms, contributing to costly delays in accurate diagnoses. Four women were aware of a family history of clotting when the event occurred, 13 had such a history but lacked awareness until the clotting event, and three had no known history. Among women with awareness of their family history, blood clot diagnosis occurred sooner, promoting survival and efficiencies in health care. Implications for communicating about family history of thrombosis are considered.

Paternal factor V Leiden and recurrent pregnancy loss: a new concept behind fetal genetics?

BACKGROUND

In up to 50% of couples affected by recurrent pregnancy loss, no identifiable cause is established. Fetal and maternal factors may be equally important in the establishment and maintenance of the placental/maternal arteriovenous anastomoses. Therefore,the inheritance of thrombophilia-related genes may be an important factor in the pathophysiology of recurrent pregnancy loss. Most of the research on recurrent pregnancy loss and thrombophilia has focused on maternal factors, but little is known about the paternal contribution.

OBJECTIVES

On that basis, we studied the association between inherited paternal thrombophilias and recurrent pregnancy loss in a narrowly selective group of 42 Argentine males from couples that presented without any known risk factors for recurrent pregnancy loss.

PATIENTS AND METHODS

The genotypic distributions of factor (F) V Leiden and prothrombin G20210A among cases were compared with those from a reference group composed of 200 Argentine men.

RESULTS

We found a significant difference in the distribution of FV Leiden between both groups (16.7% vs. 3.0%), but no difference was found in the distribution of prothrombin G20210A (2.4% vs.2.0%). Those couples with paternal FV Leiden carriage would be six times more likely to experience recurrent pregnancy loss despite no other apparent cause (OR = 6.47; 95% CI, 2.06–20.39).

CONCLUSION

We found evidence of an association between the paternal carriage of FV Leiden and the predisposition to recurrent pregnancy loss, thereby supporting the hypothesis that genetic contributions from both parents are essential factors in the development of this obstetric disorder.

Inherited Thrombophilia

Thrombophilia alters normal hemostasis, shifting the balance in favor of thrombus formation. Inherited conditions include factor V Leiden (FVL), prothrombin G20210A mutation, deficiencies in natural anticoagulants (antithrombin [AT], protein C, and protein S), hyperhomocysteinemia, and elevations in clotting factors (factors VIII and XI). Although FVL and prothrombin mutation are common disorders, deficiencies in the natural anticoagulants are rare. The risk of initial thrombosis conferred by inherited thrombophilia varies with the highest risk in those homozygous for either FVL or prothrombin mutation, or with AT deficiency. In the nonpregnant patient, the presence of a thrombophilia does not affect treatment of an acute event. Although vitamin B supplementation has been shown to decrease the levels of homocysteine, the treatment has failed to show a benefit in thrombus prevention and is therefore not recommended.

Evaluation and management of stroke in young adults

PURPOSE OF REVIEW

This article provides an overview of the evaluation and management of ischemic stroke in young adults, with an emphasis on cervical artery dissection, patent foramen ovale, and hypercoagulable states.

RECENT FINDINGS

The incidence of ischemic stroke in young patients is increasing, although the reasons remain unclear. Patients with ischemic stroke at a young age are more likely to die at an early age than their peers. Well-established vascular risk factors are prevalent in young stroke patients. Recent studies have informed the treatment of dissection and patent foramen ovale among others. The utility of testing for hypercoagulable states in ischemic stroke is unclear.

SUMMARY

Ischemic stroke in young adults is a major public health problem. A wide range of etiologies of ischemic stroke is found in this age group. A careful history, thorough examination, and methodical workup are essential. Specific management is predicated on identification of the underlying etiology.

Clinical syndromes associated with acquired antithrombin deficiency via microvascular leakage and the related risk of thrombosis

Antithrombin (AT) is a 65kDa glycoprotein belonging to a group of inhibitory factors known as serpins (serine protease inhibitors). It plays a critical role in the inhibition of coagulation and inflammation processes within the environment of the vascular endothelium. Inadequate levels of functional AT in plasma results in an increased risk of thrombotic events, both venous and arterial. AT deficiency can be inherited or acquired. Congenital AT deficiency is the most severe inherited thrombophilic condition with an odds ratio of 20 for the increased risk of venous thrombosis. Acquired AT deficiency occurs in a variety of physiologic and pathologic medical conditions with similar risks of increased thrombosis. In this article, we review clinical settings characterized by an acquired AT deficiency largely or partly subsequent to protein microvascular leakage. Other different mechanisms of AT depletion are implied in some clinical conditions together with endothelial loss, and, therefore, outlined. In addition, we provide a description of the current knowledge on the specific mechanisms underlying endothelial AT leakage and on the consequences of this protein decrease, specifically looking at thrombosis. We identify potential directions of research that might prove useful in patients with acquired AT deficiency.

Mechanistic phenotypes: an aggregative phenotyping strategy to identify disease mechanisms using GWAS data

A single mutation can alter cellular and global homeostatic mechanisms and give rise to multiple clinical diseases. We hypothesized that these disease mechanisms could be identified using low minor allele frequency (MAF<0.1) non-synonymous SNPs (nsSNPs) associated with “mechanistic phenotypes”, comprised of collections of related diagnoses. We studied two mechanistic phenotypes: (1) thrombosis, evaluated in a population of 1,655 African Americans; and (2) four groupings of cancer diagnoses, evaluated in 3,009 white European Americans. We tested associations between nsSNPs represented on GWAS platforms and mechanistic phenotypes ascertained from electronic medical records (EMRs), and sought enrichment in functional ontologies across the top-ranked associations. We used a two-step analytic approach whereby nsSNPs were first sorted by the strength of their association with a phenotype. We tested associations using two reverse genetic models and standard additive and recessive models. In the second step, we employed a hypothesis-free ontological enrichment analysis using the sorted nsSNPs to identify functional mechanisms underlying the diagnoses comprising the mechanistic phenotypes. The thrombosis phenotype was solely associated with ontologies related to blood coagulation (Fisher's p = 0.0001, FDR p = 0.03), driven by the F5, P2RY12 and F2RL2 genes. For the cancer phenotypes, the reverse genetics models were enriched in DNA repair functions (p = 2×10−5, FDR p = 0.03) (POLG/FANCI, SLX4/FANCP, XRCC1, BRCA1, FANCA, CHD1L) while the additive model showed enrichment related to chromatid segregation (p = 4×10−6, FDR p = 0.005) (KIF25, PINX1). We were able to replicate nsSNP associations for POLG/FANCI, BRCA1, FANCA and CHD1L in independent data sets. Mechanism-oriented phenotyping using collections of EMR-derived diagnoses can elucidate fundamental disease mechanisms.

Risk Factors and Treatment Strategies in Patients With Retinal Vascular Occlusions

Retinal vein occlusion (RVO) and retinal artery occlusion (RAO) cause significant visual impairment. The role of thrombophilia and cardiovascular testing is uncertain, and optimal treatment strategies have not been determined. We reviewed medical records of 39 patients with RVO and RAO (23 women and 16 men). Thrombophilia and cardiovascular evaluations were performed and outcomes were reviewed. In all, 24 (61.5%) patients had at least 1 thrombophilia. Elevated factor VIII levels were found in RVO (n = 5) but not in RAO. There are no other significant differences in thrombophilias in RVO compared to those in RAO. Most patients had hypertension(41.2% RAO and 55% RVO) and hyperlipidemia (35.5% RAO and 81.8% RVO). In all, 4 women were using oral contraceptives, 2 were pregnant or postpartum. Follow-up data was available for 28 patients (13 RAO, 15 RVO). Nineteen were treated with aspirin, four with warfarin, and one with low molecular weight heparin. Eight patients reported improvement in vision at time of follow-up (5 RAO, 3 RVO). Multiple risk factors are associated with RVO and RAO, and a complete assessment should include thrombophilia and cardiovascular studies.

Pharmacokinetics of recombinant human antithrombin in delivery and surgery patients with hereditary antithrombin deficiency

Population pharmacokinetic (PK) analyses were conducted to refine dosing recommendations for recombinant human anti-thrombin therapy in surgery and delivery patients with hereditary antithrombin deficiency (HD). Single-dose PK data from patients with HD and nonlinear mixed-effects modeling were used to devise a dosing regimen to target antithrombin (AT) activity levels between 80% and 120% of normal. External validation with data from a phase 3 trial confirmed the correctness of a covariate-free model for surgery patients, but dosing adjustment was necessary for delivery patients. After different covariates were tested, the model was updated to incorporate the influential covariate, delivery. Simulations were used to develop a therapeutic drug-monitoring scenario that results in steady state AT activity levels within the target range as quickly as practically feasible. Data from a second clinical trial provided additional external validation and confirmed the accuracy of the dosing model for both groups of patients.

Reduced protein C Global assay level in infertile women prior to IVF-ET treatment

PURPOSE

In the last few years more robust evidence is emerging to point out at an increased rate of prematurity and low birth weight in singleton pregnancies following ART. Whether this increased rate is related to ART practice or to infertility per se, is still an open question. Our aim in this study was to explore this question by evaluating Protein C (ProC) Global assay in infertile women before ART treatment.

METHODS

A cohort of 95 unselected and consecutive infertile women, eligible for ART, was prospectively recruited for the study. The control group included 77 matched healthy fertile women with a history of spontaneous conceptions. Pro C Global assay was evaluated in both groups. A full thrombophilic work-up was performed in the study group.

RESULTS

ProC Global assay level was found to be significantly lower in the study as compared to the control group, corresponding to 0.78 ± 0.16 and 0.88 ± 0.16, respectively (P < 0.01). As well, abnormal ProC Global assay level of ≤ 0.8 was significantly higher in the study as compared to control group corresponding to 53 % and 29 %, respectively. ProC Global assay level was significantly lower in women within the study group found to have APCR, factor V Leiden and high factor VIII level, any thrombophilia or combined thrombophilia when compared to women without these thrombophilic risk factors.

CONCLUSIONS

Reduced ProC Global assay level is encountered in infertile women prior to ART treatment. This finding may suggest a unique anticoagulation Protein C pathway in infertile as compared to fertile women. Further studies are encouraged to explore this finding.

Thromboembolische Komplikationen und die Bedeutung der Thrombophilie in der Schwangerschaft

Ziel: Überblick über Pathogenese, Prophylaxe und Therapie thromboembolischer Komplikationen.

Methode: Literaturrecherche in Pubmed.

Ergebnisse und Diskussion: In der Schwangerschaft verändert sich die plasmatische Gerinnung zugunsten der prokoagulatorischen Eigenschaften des Blutes, um dem Blutverlust bei der Geburt entgegenzuwirken. Venöse Thromboembolien (VTE) gehören in der westlichen Welt weiterhin zu den führenden Ursachen für schwerwiegende mütterliche Morbidität und Sterblichkeit. Das Risiko, eine venöse Thromboembolie zu erleiden, steigt in der Schwangerschaft um das 4-5-fache und in der Postpartum-Periode sogar um das 20-fache. Insbesondere bei Patientinnen mit einer erworbenen oder hereditären Thrombophilie kann es zu vaskulär bedingten Schwangerschaftskomplikationen kommen. Hierzu zählen die tiefe Beinvenenthrombose, die Lungenembolie, aber auch rezidivierende Aborte bei AntiphospholipidSyndrom. Empfehlungen im Hinblick auf die Notwendigkeit einer prophylaktischen Gabe von niedermolekularem Heparin werden bei den verschiedenen Thrombophilien individuell getroffen. Sie sind abhängig von der Art der Thrombophilie, der Eigen- und Familienanamnese hinsichtlich tiefer Beinvenenthrombosen, Lungenembolien oder rezidivierender Aborte sowie dem Verlauf der Schwangerschaft. Eine generelle Empfehlung für eine prophylaktische Heparinisierung bei laborchemisch nachgewiesener Thrombophilie gibt es nicht.

Als antikoagulatorische Therapie der Wahl bei thromboembolischen Komplikationen in der Schwangerschaft gelten die niedermolekularen Heparine, da sie nebenwirkungsarm und nicht teratogen sind. Die Therapie der akuten VTE sollte in der Regel bis 6 Wochen post part-um bei einer Gesamtdauer von mindestens 3 Monaten durchgeführt werden. Liegt ein Anti-phospholipid-Syndrom vor, wird zusätzlich Acetylsalicylsäure (75–100 mg/Tag) empfohlen. Da ein Großteil der tiefen Beinvenenthrombosen in der Schwangerschaft proximal auftreten, ist das Risiko eines postthrombotischen Syndroms hoch. Zur Minimierung von Früh- und Spätkomplikationen bei Thromboembolien in der Schwangerschaft ist eine frühzeitige Diagnostik sowie eine risikoadaptierte Prophylaxe entscheidend.

Distinct frequencies and mutation spectrums of genetic thrombophilia in Korea in comparison with other Asian countries both in patients with thromboembolism and in the general population

Hereditary natural anticoagulant deficiencies are the major cause of genetic thrombophilia in Asia. Given the growing acknowledgment of the risk of venous thromboembolism in Asian populations, we investigated the frequency and mutation spectrums of natural anticoagulant deficiency in Korea. The group of patients consisted of consecutive patients with venous thromboembolism screened for thrombophilia. Genetic tests were performed on suspicion of natural anticoagulant deficiency. For the population group, >3,000 individuals were screened from routine check-ups, and those with a low level (<1(st) percentile) of natural anticoagulant underwent genetic tests. Mutations were detected by direct sequencing of PROC, PROS1, and SERPINC1, followed by additional multiplex ligation-dependent probe amplification for PROS1 and SERPINC1 for dosage mutations. Among 500 patients screened, 127 were suspected of having a natural anticoagulant deficiency, and this was genetically confirmed in 71: protein C deficiency in 36 (50.7%), antithrombin deficiency in 21 (29.6%), and protein S deficiency in 14 (19.7%). Among 3,129 individuals from the population who were screened, the frequency of natural anticoagulant deficiency was ~1.0%: antithrombin deficiency 0.49%, protein C deficiency 0.35%, and protein S deficiency 0.16%. Two PROC mutations causing type I protein C deficiency were prevalent (Arg211Trp and Met406Ile in patients and Arg211Trp in the population). Two SERPINC1 mutations causing type II antithrombin deficiency, Arg79Cys and Ser158Pro, were prevalent in the population group. This is the first study on the genetic epidemiology of natural anticoagulant deficiencies in Korea. The results demonstrated that the frequencies and spectrum of mutations underlying genetic thrombophilia in Korea are different not only from those in Caucasians but also those in other Asian populations.

Factor IX-Padua enhances the fibrinolytic resistance of plasma clots

Hypercoagulable conditions may determine a hypofibrinolytic state by increasing the activation of thrombin-activatable fibrinolysis inhibitor (TAFI). Factor (F)IX-Padua is a mutated FIX with an eight-fold increased clotting activity and associates with a higher venous thrombotic risk. We evaluated the influence of FIX-Padua on TAFI-mediated regulation of fibrinolysis. A subject hemizygous for FIX-Padua, two family members (heterozygous and normal) and six healthy controls were studied. Clot lysis, TAFI activation and thrombin generation were evaluated in contact-inhibited plasma challenged with low concentrations of tissue factor. Fibrinolysis times were significantly longer in FIX-Padua carriers than controls. The difference disappeared when activated TAFI (TAFIa) was inhibited, when TAFI activation was avoided or when clotting was made independent of FIX. TAFIa generation was markedly enhanced in FIX-Padua carriers as compared to controls, and this could be explained by a greater thrombin generation in the former. Hyperactive FIX, but not wild-type FIX, enhanced fibrinolytic resistance also when the FXI-dependent positive feedback was blocked by a neutralising anti-FXI antibody. This thrombin-mediated, TAFI-dependent down-regulation of fibrinolysis provides new clues for explaining the heightened thrombotic risk in subjects carrying the FIX-Padua mutation.

Influence of proband’s characteristics on the risk for venous thromboembolism in relatives with factor V Leiden or prothrombin G20210A polymorphisms

The risk for venous thromboembolism in relatives with factor V Leiden or prothrombin G20210A differs according to the probands’ selection. Relatives belonging to families with heterozygous probands with venous thromboembolism have the highest risk for venous thromboembolism.

Hypercoagulability in a newborn with concomitant homozygous factor V Leiden and severe homozygous protein C deficiency type 1

This is a case report of a female newborn presented with skin necrotic lesions 1 week after delivery. Laboratory investigations revealed severe homozygous protein C deficiency associated with homozygous factor V Leiden, although her pregnancy and perinatal periods were otherwise uneventful, with negative family history of thrombotic or bleeding disorders. Patient stabilization was established by supportive measures and long-term administration of fresh frozen plasma and warfarin.

Retinal venous thrombosis in a young patient with coagulation factor XII deficiency

CASE REPORT

A 35-year-old woman, with no relevant medical history, was referred for sudden vision loss in the left eye. Ophthalmological examination showed best corrected visual acuity of 1.0 in the right eye and 0.3 in left eye, with normal anterior pole and intraocular pressure. Fundus examination of the left eye revealed a venous thrombosis in the superior temporal branch, with dilated and tortuous retinal veins. The patient was referred to the hematology unit for thrombophilia study, and was diagnosed with a coagulation XII or Hageman factor deficiency.

DISCUSSION

The development of retinal vessel occlusions, in patients under 50 years of age, is frequently associated with thrombophilia or hypercoagulability disorders. Factor XII deficiency is a rare condition, and its presence could contribute to a higher risk of thromboembolic events.

Testing for inherited thrombophilia and consequences for antithrombotic prophylaxis in patients with venous thromboembolism and their relatives. A review of the Guidelines from Scientific Societies and Working Groups

The clinical penetrance of venous thromboembolism (VTE) susceptibility genes is variable, being lower in heterozygous carriers of factor V Leiden and prothrombin 20210A (mild thrombophilia), and higher in the rare carriers of deficiencies of antithrombin, protein C or S, and those with multiple or homozygous abnormalities (high-risk thrombophilia). The absolute risk of VTE is low, and the utility of laboratory investigation for inherited thrombophilia in patients with VTE and their asymptomatic relatives has been largely debated, leading to the production of several Guidelines from Scientific Societies and Working Groups. The risk for VTE largely depends on the family history of VTE. Therefore, indiscriminate search for carriers is of no utility, and targeted screening is potentially more fruitful. In patients with VTE inherited thrombophilia is not scored as a determinant of recurrence, playing a minor role in the decision of prolonging anticoagulation; indeed, a few guidelines consider testing worthwhile to identify carriers of high-risk thrombophilia, particularly those with a family history of VTE. The identification of the asymptomatic carrier relatives of the probands with VTE and thrombophilia could reduce cases of provoked VTE, offering them primary antithrombotic prophylaxis during risk situations. In most guidelines, this is considered justified only for relatives of probands with a deficiency of natural anticoagulants or multiple abnormalities. Counselling the asymptomatic female relatives of individuals with VTE and/or thrombophilia before pregnancy or the prescription of hormonal treatments should be administered with consideration of the risk driven by the type of thrombophilia and the family history of VTE.

Association between Thrombophilia and the Post-Thrombotic Syndrome

The post thrombotic syndrome (PTS) is a chronic condition that develops in 20%–40% of deep vein thrombosis (DVT) patients. While risk factors that predispose to the development of venous thromboembolism (VTE) are widely known, factors that influence the development of PTS after DVT have not been well elucidated. Over 10% of the general population is affected by one or more identifiable inherited thrombophilias which have been shown to underlie at least 1/3 of cases of VTE. The various thrombophilias are important risk factors for VTE, but it is unknown whether they also increase the risk for development of PTS. We performed a review of studies that have reported on the association between thrombophilia and the development of PTS in populations of patients with DVT and with chronic venous ulcers. Studies vary with regards to the definition of PTS, study design, follow-up period, and present conflicting results. Based on these results, the question of whether thrombophilia predisposes to the development of PTS remains unanswered.

Portal vein thrombosis: should anticoagulation be used?

Portal vein thrombosis (PVT) can contribute to significant morbidity and mortality; in patients with cirrhosis, this can make transplant more technically challenging. Additionally, the clot may extend further into the mesenteric and splenic veins, and disturbance of the hepatic blood flow may lead to faster progression of the cirrhosis. Development of PVT is associated with local risk factors, and many patients have associated systemic prothrombotic factors. Anticoagulation in noncirrhotic patients should be initiated at diagnosis, using low-molecular-weight heparin overlapping with vitamin K antagonists. Cirrhotic patients with PVT should be screened for varices and then anticoagulated with low-molecular-weight heparin for at least a 6-month period. All patients should be assessed for triggering factors and tumors, as well as systemic prothrombotic factors. Newer evidence suggests that prophylactic anticoagulation in patients with cirrhosis may have a role in clinical management with decreased incidence of PVT and improved survival; further study is needed.

Congenital Thrombophilia and Intracardiac Thrombosis: Probably an Underdiagnosed Event

Background

To investigate the number of patients with congenital thrombophilia who presented an intracardiac thrombosis.

Methods

Personal files were reevaluated together with a time-unlimited search of the literature.

Results

Twenty-five patients with intracardiac thrombosis and congenital thrombophilia have been gathered from the literature including the two personal cases. The distribution observed in thrombophilia patients is similar for left side or right side heart (9 vs 11 cases). The left ventricle and the right ventricle were involved in six or five instances, respectively. In one case, both ventricles were involved. On the contrary, the left atrium was involved in three cases whereas the right atrium was affected in six cases. In the remaining cases, more than one heart chamber was involved.

Conclusions

In “normal” subjects, left side thromboses are predominant once catheter-associated thrombi are excluded. The reason of this discrepancy lies in the greater prothrombotic effect exercised by congenital thrombophilia on venous thrombosis compared to arterial thrombosis. The relative high prevalence of cardiac thrombosis seen in patients with antithrombin and protein C deficiencies indicated that a cardiac evaluation should be carried out in all patients with these two defects.

Current knowledge on the genetics of incident venous thrombosis

The genetic burden underlying venous thrombosis (VT) is characterized by a sibling relative risk of 2.5 and a strong heritability whose estimates varied from 35% to 60% according to different studies. However, the genetic factors identified so far only explain about 5% of VT heritability and just 16 genes have been robustly associated with the susceptibility to VT, most of them affecting the coagulation cascade. Eight of these have been identified during the last 5 years, thanks to the development of high-throughput micro-array genotyping technologies, which have radically changed the research landscape in human genetics. The present work is aimed at providing a historical review of the known genetic factors contributing to VT risk, as well as discussing future research strategies to follow to disentangle the whole spectrum of genetic variants associated with VT.

Management of patients with unprovoked venous thromboembolism: an evidence-based and practical approach

OPINION STATEMENT

The management of patients with unprovoked venous thromboembolism is a common and challenging clinical problem. Although the initial antithrombotic management is well-established, there is uncertainty about the optimal long-term anticoagulant management, specifically whether patients should receive a short (i.e., 3- to 6-month) duration of anticoagulant therapy or indefinite anticoagulation. Factors that may be considered to estimate patients' risk for recurrent thromboembolism include the mode of initial clinical presentation, as deep vein thrombosis or pulmonary embolism, patient sex, antecedent hormonal therapy use, thrombophilia, D-dimer levels, and residual vein occlusion in patients with deep vein thrombosis. Many of these factors have been integrated into clinical prediction guides which stratify patients with unprovoked venous thromboembolism according to their risk for disease recurrence and, thereby, can assist clinicians in decisions about the duration of anticoagulation. The objective of this review is to consider the evidence relating to the clinical significance of purported risk factors and provide a practical case-based approach to guide decisions on duration of anticoagulation for patients with unprovoked venous thromboembolism.

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.

Common genetic risk factors for venous thrombosis in the Chinese population

Venous thrombosis is a major medical disorder caused by both genetic and environmental factors. Little is known about the genetic background of venous thrombosis in the Chinese population. A total of 1,304 individuals diagnosed with a first venous thrombosis and 1,334 age- and sex-matched healthy participants were enrolled in this study. Resequencing of THBD (encoding thrombomodulin) in 60 individuals with venous thrombosis and 60 controls and a functional assay showed that a common variant, c.-151G>T (rs16984852), in the 5' UTR significantly reduced the gene expression and could cause a predisposition to venous thrombosis. Therefore, this variant was genotyped in a case-control study, and results indicated that heterozygotes had a 2.80-fold (95% confidence interval = 1.88-4.29) increased risk of venous thrombosis. The THBD c.-151G>T variant was further investigated in a family analysis involving 176 first-degree relatives from 38 index families. First-degree relatives with this variant had a 3.42-fold increased risk of venous thrombosis, and their probability of remaining thrombosis-free was significantly lower than that of relatives without the variant. In addition, five rare mutations that might be deleterious were also identified in thrombophilic individuals by sequencing. This study is the largest genetic investigation of venous thrombosis in the Chinese population. Further study on genetics of thrombosis should focus on resequencing of THBD and other hemostasis genes in different populations.

Antibody SPC-54 provides acute in vivo blockage of the murine protein C system

Multiple protective effects of pharmacological activated protein C (APC) are reported in several organ pathologies. To help evaluate the endogenous murine PC system, we characterized a rat monoclonal anti-mouse PC antibody, SPC-54, which inhibited the amidolytic and anticoagulant activities of murine APC by>95%. SPC-54 blocked active site titration of purified APC using the active site titrant, biotinylated FPR-chloromethylketone, showing that SPC-54 blocks access to APC's active site to inhibit all enzymatic activity. A single injection of SPC-54 (10mg/kg) neutralized circulating PC in mice for at least 7days, and immunoblotting and immuno-precipitation with protein G-agarose confirmed that SPC-54 in vivo was bound to PC in plasma. Pre-infusion of SPC-54 in tissue factor-induced murine acute thromboembolism experiments caused a major decrease in mean survival time compared to controls (7min vs. 42.5min, P=0.0016). SPC-54 decreased lung perfusion in this model by 54% when monitored by vascular perfusion methodologies using infrared fluorescence of Evans blue dye. In LD50 endotoxemia murine models, SPC-54 infused at 7hr after endotoxin administration increased mortality from 42% to 100% (P<0.001). In summary, monoclonal antibody SPC-54 ablates in vitro and in vivo APC protective functions and enzymatic activity. The ability of SPC-54 to block the endogenous PC/APC system provides a powerful tool to understand better the role of the endogenous PC system in murine injury models and in cell bioassays and also to neutralize the enzymatic activities of murine APC in any assay system.

The challenge of managing hemophilia A and STEC-induced hemolytic uremic syndrome

BACKGROUND

The hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy leading to acute kidney injury in children. In most cases it is triggered by an infection caused by Shiga-like toxin-producing Escherichia coli (STEC). Endothelial damage plays a central role in the pathogenesis of disease. Hemophilia A is a genetic disorder leading to factor VIII (FVIII) deficiency, an important factor in the coagulation system.

CASE

Here we describe a hemophilia A patient who developed HUS due to a STEC O26 infection. The patient developed not only acute kidney injury, but also severe gastro-intestinal and neurological complications. Increased amounts of recombinant FVIII (rFVIII) had to be administered during the acute phase of the disease to reach acceptable blood levels of FVIII, in order to control the hemorrhagic colitis and to prevent severe neurological complications.

CONCLUSION

The patient's treatment schedule of rFVIII during the HUS period was a serious challenge, and we cannot exclude that it contributed to the severity of the HUS by enhancing the thrombotic microangiopathic process. The role of factor VIII administration in the severe outcome of this disease is discussed.