Thrombophilia and its impact on pregnancy

Benefits and risks of low molecular weight heparin use on reproductive outcomes: A retrospective cohort study

OBJECTIVE

Low molecular weight heparin (LMWH) has been given to reproductive-age women with various indications. This study aims to assess the benefits and risks of such use.

MATERIALS AND METHODS

We retrospectively reviewed data (n = 204) between Jan 2016 and May 2019. Logistic regression analysis was conducted to evaluate the correlation between indications and reproductive outcomes.

RESULTS

LMWH use had higher odds of live birth in women less than 30 years of age (OR: 4.98; 95% CI = 1.13-21.98; p = 0.034) and with protein S deficiency (OR: 3.90; 95% CI = 1.77-8.59; p = 0.001). For the subgroup of recurrent pregnant loss, LMWH use was only advantageous to women with protein S deficiency (OR: 2.45; 95%:1.01-5.97; p = 0.048). Risks such as preterm delivery, small-for-gestational-age, placental abruption, antepartum/postpartum hemorrhage were not significantly increased among subgroups. Women treated with LMWH and who had successful live births (n = 171) had a slightly increased risk of postpartum hemorrhage compared to controls (n = 8058) during this period in our institution (2.9% vs 1.2%, p < 0.001).

CONCLUSION

LMWH administration produces a higher chance of live-birth to women younger than 30 years of age or with protein S deficiency. However, risk of postpartum hemorrhage is increased.

Thrombophilia Impact on Treatment Decisions, Subsequent Venous or Arterial Thrombosis and Pregnancy-Related Morbidity: A Retrospective Single-Center Cohort Study

(1) Background: Thrombophilia testing utility has remained controversial since its clinical introduction, because data on its influence on treatment decisions are limited. (2) Methods: We conducted a single-center retrospective cohort study of 3550 unselected patients referred for thrombophilia consultation at the Bern University Hospital in Switzerland from January 2010 to October 2020. We studied the influence of thrombophilia testing results on treatment decisions and evaluated the association between thrombophilia and thromboembolic and pregnancy-related morbidity events after testing up to 03/2021. (3) Results: In 1192/3550 patients (34%), at least one case of thrombophilia was found and 366 (10%) had high-risk thrombophilia. A total of 211/3550 (6%) work-ups (111/826 (13%) with low-risk thrombophilia and 100/366 (27%) with high-risk thrombophilia) led to an appropriate decision to extend or initiate anticoagulation, and 189 (5%) negative results led to the withholding of anticoagulation therapy inappropriately. A total of 2492 patients (69%) were followed up for >30 days, with a median follow-up of 49 months (range, 1−183 months). Patients with high-risk thrombophilia had a higher risk of subsequent venous thromboembolic events and pregnancy-related morbidity compared to those without thrombophilia. (4) Conclusions: Our study demonstrated the limited usefulness of thrombophilia work-up in clinical decision-making. High-risk thrombophilia was associated with subsequent venous thromboembolism and pregnancy-related morbidity.

Changes in Coagulation During Twin Pregnancies

To investigate changes in coagulation during twin pregnancies. Methods: A total of 108 women with twin pregnancies and 442 women with singleton pregnancies were recruited. Coagulation tests, including fibrinogen (Fib), activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT), were performed during the course of the pregnancy. The level of fibrinogen gradually increased during singleton pregnancies, while the APTT and PT levels showed a decreasing trend with increasing gestational weeks. In twin pregnancies, the changes in PT and TT were similar, but other parameters displayed a different trend. Fibrinogen showed no significant difference between the second and third trimesters, while APTT showed an increasing trend from the second trimester to the third trimester. Compared with singleton pregnancies, the level of fibrinogen was higher in women pregnant with twins. APTT was longer in women pregnant with twins than in women with singleton pregnancies in the third trimester. PT was shorter in women pregnant with twins than in women with singleton pregnancies in the first and third trimesters. TT was shorter in women pregnant with twins than in women with singleton pregnancies in the first and second trimesters. Through this retrospective longitudinal analysis, this study presents the main coagulation parameter changes in singleton and twin pregnancies and confirms that coagulation is more enhanced in twin pregnancies than in singleton pregnancies.

Thromboprophylaxis and maternal-fetal outcomes of women with serum markers for hereditary thrombophilia and previous obstetric complications

Abstract Objectives: to evaluate the maternalfetal outcomes of thromboprophylaxis with enoxa parin based on scoring system in women with serum markers for hereditary thrombophilia and previous obstetric complications. Methods: a retrospective study was undertaken based on data collected from clinical records. We included 54 pregnant women with serum markers for hereditary thrombophilia undergoing therapeutic intervention with enoxaparin in the period from November 2009 to December 2013. The initial dose of low molecular weight heparin was guided by a scoring system. The maternalfetal outcomes of previous pregnancies and, subsequently, the treatment were compared using the chisquare (χ2) test with the Yates correction and Fisher's Exact Test; p<0.05 was considered significant. Results: we observed significant reduction in fetal/perinatal deaths (p<0.05) and spontaneous abortions (p<0.001) after intervention. The live births at fullterm delivery (p<0.001) and live births at preterm delivery (p<0.05) increased significantly after intervention. Conclusions: the therapeutic intervention with enoxaparin based on scoring system during pregnancy seems to improve the fetal prognosis.

The Prevalence of Thrombophilia in Women With Recurrent Fetal Loss and Outcome of Anticoagulation Therapy for the Prevention of Miscarriages

OBJECTIVE

To estimate the prevalence of thrombophilia in women with recurrent miscarriages and to assess the effect of antithrombotic therapy.

DESIGN

A retrospective cohort study between the years 2004 and 2010.

SETTING

A hypercoagulation community clinic in northern Israel.

PATIENTS

Four hundred ninety pregnant women referred for thrombophilia screening.

MAIN OUTCOME MEASURES

Screening results for thrombophilia and antithrombotic treatment with enoxaparin, aspirin, or both and pregnancy outcomes.

RESULTS

The most common thrombophilia in our study group was factor V Leiden mutation with a prevalence of 20.9% followed by protein S deficiency with a prevalence of 19%. Live birth rate was higher in the group of women who received enoxaparin regardless of whether a specific thrombophilia could be found. This finding was more pronounced in women who had ≥4 miscarriages.

CONCLUSION

The prevalence of thrombophilia was higher in our study group than in the general population. Furthermore, treatment with enoxaparin might improve the rate of live births in women with or without evidence of thrombophilia, especially in women with ≥4 miscarriages.

The Impact of Inherited Thrombophilia Types and Low Molecular Weight Heparin Treatment on Pregnancy Complications in Women with Previous Adverse Outcome

PURPOSE

To assess the distribution of births and spontaneous abortions, first-trimester abortion (FTA) and mid-trimester abortion (MTA), in untreated (n=128) and low molecular weight heparin (LMWH) treated pregnancies (n=50) of the same women with inherited thrombophilias and adverse pregnancy outcome (APO) in previous pregnancies. We particularly investigated the impact of LMWH on reducing the pregnancy complications in two thrombophilia types, "Conventional" and "Novel".

MATERIALS AND METHODS

50 women with inherited thrombophilia (26 Conventional and 24 Novel) and APO in previous pregnancies were included in the study. Conventional group included factor V Leiden (FVL), prothrombin G20210A (PT) mutations and antithrombin (AT), protein S (PS), and protein C (PC) deficiency, while the Novel group included methylentetrahydrofolate-reductase (MTHFR), plasminogen activator inhibitor-1 (PAI-1), and angiotensin converting enzyme (ACE) polymorphism. APO was defined as one of the following: preterm birth (PTB), fetal growth restriction (FGR), preeclampsia (PE), intrauterine fetal death (IUFD), placental abruption (PA) and deep venous thrombosis (DVT).

RESULTS

There was no difference in distribution of births and spontaneous abortions between Conventional and Novel thrombophilia in untreated pregnancies (χ²=2.7; p=0.100) and LMWH treated pregnancies (χ²=0.442; p=0.506). In untreaed pregnancies thrombophilia type did not have any impact on the frequency of FTA and MTA (χ²=0.14; p=0.711). In birth-ended pregnancies LMWH treatement reduced the incidence of IUFD (p=0.011) in Conventional and FGR, IUFD, and PTB in Novel thrombophilia group.

CONCLUSION

The equal impact of two thrombophilia types on the pregnancy outcomes and a more favorable effect of LMWH therapy on pregnancy complications in Novel thrombophilia group point the need for Novel thrombophilias screening and the future studies on this issue should be recommended.

Maternal thrombophilia and adverse pregnancy outcome: a case-control study

OBJECTIVE

To assess the risk of adverse pregnancy outcomes in patients with acquired and/or congenital thrombophilia factors.

PATIENTS AND METHODS

A cohort of 130 women with a history of pregnancy loss and no successful gestation were investigated for the presence of congenital and acquired thrombophilia factors, and then compared with a control group of 130 healthy women who had had at least one successful gestation and no pregnancy loss, and were screened for congenital and acquired thrombophilia factors.

RESULTS

Acquired and congenital thrombophilia factors were found in 30 (23%) patients and in 14 (10.8%) controls (p < 0.015). The presence of ≥1 congenital thrombophilia factor was associated with pregnancy loss with an odds ratio of 2.46 (p = 0.040). Moreover, women who had had >1 early fetal loss had a 2.85-fold risk of being carriers of congenital thrombophilia factors, compared to the controls.

CONCLUSION

Our study showed the increased risk of miscarriage in patients with congenital thrombophilia factors and >1 early fetal loss.

Pregnancy-Related Venous Thromboembolism

Pregnancy is associated with an increased risk of venous thromboembolism (VTE), with a reported incidence ranging from 0.49 to 2 events per 1000 deliveries. Risk factors include advanced maternal age, obesity, smoking, and cesarian section. Women with a history of previous VTE are at a 4-fold higher risk of recurrent thromboembolic events during subsequent pregnancies. Additionally, the presence of concomitant thrombophilia, particularly factor V Leiden (homozygosity), prothrombin gene mutation (homozygosity), or antiphospholipid syndrome (APS), increases the risk of pregnancy-related VTE. Low-molecular-weight heparin (LMWH) and unfractionated heparin (UFH) are the drugs of choice for anticoagulation during pregnancy. LMWH is preferred due to ease of use and lower rates of adverse events. Women with high thromboembolic risk particularly those with a family history of VTE should receive antepartum thromboprophylaxis. Women with low thromboembolic risk or previous VTE caused by a transient risk factor (ie, provoked), who have no family history of VTE, may undergo antepartum surveillance. Postpartum anticoagulation can be considered in women with both high and low thromboembolic risk.

Differences in thrombotic risk factors in black and white women with adverse pregnancy outcome

INTRODUCTION

Black women have an increased risk of adverse pregnancy outcomes and the characteristics of thrombotic risk factors in this population are unknown. The objective of this study was to examine the racial differences in thrombotic risk factors among women with adverse pregnancy outcomes.

METHODS

Uniform data were collected in women with adverse pregnancy outcomes (pregnancy losses, intrauterine growth restriction (IUGR), prematurity, placental abruption and preeclampsia) referred to Thrombosis Network Centers funded by the Centers for Disease Control and Prevention (CDC).

RESULTS

Among 343 white and 66 black women seen for adverse pregnancy outcomes, protein S and antithrombin deficiencies were more common in black women. The prevalence of diagnosed thrombophilia was higher among whites compared to blacks largely due to Factor V Leiden mutation. The prevalence of a personal history of venous thromboembolism (VTE) did not differ significantly by race. A family history of VTE, thrombophilia, and stroke or myocardial infarction (MI) was higher among whites. Black women had a higher body mass index, and a higher prevalence of hypertension, while the prevalence of sickle cell disease was approximately 27 fold higher compared to the general US black population.

CONCLUSIONS

Thrombotic risk factors differ significantly in white and black women with adverse pregnancy outcomes. Such differences highlight the importance of considering race separately when assessing thrombotic risk factors for adverse pregnancy outcomes.

Thromboembolism risk following recurrent miscarriage

Normal pregnancy is associated with extensive changes in hemostasis such that the procoagulant effect becomes dominant. The evolutionary advantage of this hypercoagulability may be to counteract the inherent instability associated with hemochorial placentation, which is unique to human beings. However, overall, there is a four- to 10-fold increased thrombotic risk throughout gestation and the postpartum period. Certain inherited or acquired thrombophilic factors may predispose to arterial and/or venous thrombosis and have a possible association with pregnancy complications, including recurrent miscarriage (RM), which affects up to 5% of couples with childbearing desire. A subgroup of women with RM has been demonstrated to be in a prothombotic state before and after pregnancy. The long-term health implications of this hypercoagulability may imply an increased risk of ischemic heart disease. Moreover, the presence of antiphospholipid antibodies rather than thrombophilic genetic defects (i.e., factor V Leiden or prothrombin G202010A mutation) in patients with RM is a determinant of thrombotic events later in life, especially among those patients having also cardiovascular risk factors. This article highlights the thromboembolic risk in nonpregnant RM patients in different thrombophilic settings and the need for thromboprophylaxis among these patients.

Positive association of Apolipoprotein E4 polymorphism with recurrent pregnancy loss in Iranian patients

PROBLEM

Numerous lines of evidence implicate Apolipoprotein E (Apo E) in lipid metabolism during pregnancy. Hence, a role for its polymorphism has been envisaged in recurrent pregnancy loss (RPL) considering major structural and functional differences between different Apo E genotypes.

METHOD OF STUDY

A case control study of 81 women with two or more pregnancy losses that did not have any other known risk factors including anatomic anomalies of the reproductive system, infections, immunologic factors, hormonal imbalances, chromosomal abnormalities and environmental factors was carried out. The control group consisted of 81 women with at least two healthy children and no RPL in their reproductive history. DNA was extracted from the peripheral blood following written consent and Apo E genotyping was carried out by amplifying exon 4 of the gene and subjecting it to digestion by HhaI restriction enzyme.

RESULTS

Genotyping was concluded by analyzing different fragment sizes produced, which resulted in finding significantly higher frequency of combined E3/E4 and E4/E4 genotypes in the patients (about 20 %) compared to the normal controls (2.4 %). The genotypes were confirmed by DNA sequencing.

CONCLUSION

Allelic frequency for E4 was 13.5 % in the patients and only 1 % in the non-RPL group. Our findings confirm and are in line with a number of similar studies carried out on other populations. Therefore, Apo E4 polymorphism seems to be contributing to the thrombophilic risk factors as a background to RPL.

Vascular associated gene variants in patients with preeclampsia: results from the Danish National Birth Cohort

OBJECTIVE

Preeclampsia has been linked to subsequent vascular disease with many shared predisposing factors. We investigated the association between severe preeclampsia, and its subtypes, and specific vascular-related polymorphisms.

DESIGN

The study was a retrospective nested case-cohort design.

SETTING

Pregnant Danish women participating in the Danish National Birth Cohort. Population. 263 cases of severe preeclampsia and 1851 random controls were selected from the Danish National Birth Cohort.

METHODS

We validated all cases of severe preeclampsia and genotyped for 108 single nucleotide polymorphisms (SNPs) that were selected based on previous publications on the association with vascular disease. Logistic models were used for statistical analyses.

MAIN OUTCOME MEASURES

Maternal polymorphisms in genomic models.

RESULTS

We found 17 of 108 SNPs associated with severe preeclampsia (p < 0.05). Women homozygous for the rs1799983 in NOS3 were 1.6-fold [95% confidence interval (CI) 1.0-2.4] more likely to develop severe preeclampsia. Women homozygous for the rs1010 SNP in VAMP8 were twofold (95%CI 1.1-3.5) more likely to deliver preterm when preeclampsia was present. Women homozygous for the rs10811661 SNP were 2.1-fold (95%CI 1.1-3.9) more likely to develop severe preeclampsia and 3.7-fold (95%CI 1.1-12.4) more likely to deliver a small-for-gestational age child when preeclampsia was present. All associations are available as Supporting Information.

CONCLUSION

We found several vascular-associated SNPs linked to severe preeclampsia; however, most of these associations are probably by pure chance, which warrants replication and further translational research. To date, no specific SNP has yet proven valuable in a clinical setting in predicting preeclampsia.

Thrombophilias and adverse pregnancy outcomes: results from the Danish National Birth Cohort

BACKGROUND

Inherited thrombophilias have inconsistently been linked to adverse pregnancy outcomes. Differences in study design, size and population could explain this heterogeneity.

OBJECTIVE

The aim of the present study was to evaluate if factor (F)V Leiden G1691A, prothrombin mutation G20210A (PTM) and methylenetetrahydrofolate reductase C677T (MTHFR) increased the risk of severe preeclampsia, fetal growth restriction, very preterm delivery, placental abruption and a composite of these outcomes also including stillbirth.

PATIENTS AND METHODS

In a nested case-cohort study of pregnant women in Denmark, we genotyped 2032 cases and 1851 random controls. Each of the medical records of the cases was validated. We calculated both genomic and allelic models, and present both models. We also performed sensitivity analyses adjusting for parity, age, smoking, body mass index and socioeconomic status.

RESULTS

In the allelic models, FV Leiden increased the risk of the composite outcome (odds ratio [OR] 1.4, 95% confidence interval [CI] 1.1-1.8), severe preeclampsia (OR 1.6, 95% CI 1.1-2.4), fetal growth restriction (OR 1.4, 95% CI 1.1-1.8) and placental abruption (OR = 1.7 (95% CI 1.2-2.4). In the sensitivity analyses, adjustment diminished these estimates slightly. PTM was not significantly associated with any of the outcomes, and MTHFR was only significantly associated with severe preeclampsia (OR 1.3, 95% CI 1.1-1.6).

CONCLUSION

FV Leiden predisposes to adverse pregnancy outcomes in a setting of Scandinavian women.

Factor seven activating protease activity levels in women with recurrent pregnancy loss

This study was designed to analyze the changes in circulating factor seven activating protease (FSAP) levels in association with the thrombophilic state of 40 women with recurrent pregnancy loss (RPL). All women were trying to conceive and were prospectively followed up until the achievement of spontaneous pregnancy. The results obtained showed that plasma FSAP activity levels were higher in RPL than in fertile women (P < .001) and represented an adverse predictor of pregnancy at multivariate analysis (P = .002). In 7 consenting RPL women, FSAP activity levels increased continuously during pregnancy until the third trimester, remained elevated immediately after delivery, and declined 6-week postpartum, although at levels that were still above the range of control women. These results suggest that FSAP activity levels might provide useful information during pregnancy progression in at-risk women, possibly acting as a predictive factor for adverse pregnancy outcome in RPL even in the absence of other well recognized thrombophilic conditions.

Association of elevated soluble P-selectin levels with fetal loss in women with a history of venous thromboembolism

INTRODUCTION

An association between pregnancy complications such as fetal loss with inherited and acquired thrombophilic defects has frequently been reported. Recently, the cell adhesion molecule P-selectin has been identified to be a strong risk factor for venous thromboembolism (VTE).

PATIENTS AND METHODS

The aim of our study was to investigate whether soluble P-selectin (sP-selectin) is also associated with fetal loss (e.g. miscarriage or stillbirth) in 304 women (median age [25th-75th percentile]: 45 [37-54] years) with a history of VTE, in whom data on pregnancy-associated complications had been evaluated. At the time of sP-selectin measurement none of the women was pregnant or had an acute VTE.

RESULTS

The prevalence of miscarriage was 21.4% and that of stillbirth was 4.6%. The median sP-selectin level of the total study population was 38.0 [31.7-44.4] ng/mL. In subjects with elevated sP-selectin levels (defined as sP-selectin ≥44.4ng/mL, representing the 75th percentile of levels in the study population) the prevalence of stillbirth was significantly higher compared to those with lower levels (10.5% vs. 2.6%, p=0.008), whereas no statistically significant difference in the prevalence of miscarriage was observed between women with and without elevated sP-selectin (17.1% vs. 22.9%, p=0.303). The odds ratio [95% CI] of elevated sP-selectin was 4.2 [1.5-12.7] for stillbirth and 0.7 [0.4-1.3] for miscarriage.

CONCLUSIONS

Elevated sP-selectin plasma levels were associated with a 4.2-fold risk for stillbirth in women with a history of VTE. Our data support a possible role of P-selectin in late pregnancy loss.

Changes in coagulation and hemodynamics during pregnancy: a prospective longitudinal study of 58 cases

PURPOSE

To investigate changes and establish reference values in coagulation, anticoagulation, fibrinolysis, anti-fibrinolysis and hemodynamics during normal pregnancy.

METHODS

A total of 58 women with singleton pregnancies were recruited. Blood and ultrasound examinations were performed in the 10th-14th, 20th-24th, and 30th-34th weeks of pregnancy. The same examinations were performed in 50 non-pregnant women who were selected as the control group.

RESULTS

Levels of fibrinogen, thrombin time, fibronectin, prothrombin activated fragments 1+2 and thrombomodulin were higher in early pregnancy than those in the control group (P < 0.05). Fibrinogen, prothrombin time, activated partial thromboplastin time, thrombin time, thromboxane B2, prothrombin activated fragments 1+2, thrombomodulin, D-dimer, and plasminogen activator inhibitor-2 were statistically different between the mid pregnancy and the control group (P < 0.05). Meanwhile, fibrinogen, prothrombin time, activated partial thromboplastin time, thrombin time, fibronectin, thromboxane B2, prothrombin activated fragments 1+2, thrombomodulin, and plasminogen activator inhibitor-2 were obviously elevated in late pregnancy as compared with the control group (P < 0.05). Moreover, fibrinogen, thromboxane B2, prothrombin activated fragment 1+2, D-dimer plasminogen, and activator inhibitor-2 gradually increased during pregnancy with some fluctuation. Prothrombin time, activated partial thromboplastin time, thrombin time, international normalized ratio, and thrombomodulin as well as systolic/diastolic ratio, pulsatility index, and resistance index in uterine arteries showed a tendency to decrease in pregnant women.

CONCLUSIONS

Coagulation, anti-coagulation, fibrinolytic and anti-fibrinolytic activities are enhanced and balanced at a higher level during pregnancy. In addition, uterine artery and umbilical artery hemodynamics become more baby friendly (i.e., high flow and low resistance).

Coagulation disorders in pregnancy: acquired and inherited thrombophilias

Both acquired and inherited thrombophilias are associated with an increased risk of pregnancy-related venous thromboembolism (VTE) as well as with adverse pregnancy outcome. However, the extension of attributable risk for each thrombophilia and outcome is still a question of debate. Thrombophilias have been investigated in connection with VTE and pregnancy complications such as: recurrent and nonrecurrent early pregnancy loss, late fetal death, placental abruption, fetal growth restriction, and preeclampsia. This review discusses the evidence of association between thrombophilias and pregnancy outcome together with issues as to clinical management and preventive strategies.

Pre-eclampsia

Pre-eclampsia remains a leading cause of maternal and perinatal mortality and morbidity. It is a pregnancy-specific disease characterised by de-novo development of concurrent hypertension and proteinuria, sometimes progressing into a multiorgan cluster of varying clinical features. Poor early placentation is especially associated with early onset disease. Predisposing cardiovascular or metabolic risks for endothelial dysfunction, as part of an exaggerated systemic inflammatory response, might dominate in the origins of late onset pre-eclampsia. Because the multifactorial pathogenesis of different pre-eclampsia phenotypes has not been fully elucidated, prevention and prediction are still not possible, and symptomatic clinical management should be mainly directed to prevent maternal morbidity (eg, eclampsia) and mortality. Expectant management of women with early onset disease to improve perinatal outcome should not preclude timely delivery-the only definitive cure. Pre-eclampsia foretells raised rates of cardiovascular and metabolic disease in later life, which could be reason for subsequent lifestyle education and intervention.

Behçet's Disease as a Model of Venous Thrombosis

Behçet's disease (BD) is a chronic inflammatory disease of unknown aetiology characterized by recurrent oral, genital aphthous ulcerations, uveitis, skin lesions and other multisystem affections associated with vasculitis. Different types of vessels, predominantly veins, can be affected in BD. The frequency of vascular lesions in BD, such as superficial and deep venous thromboses, arterial aneurysms and occlusions, ranges between 7-29%. In this review, various factors of thrombogenesis in BD, particularly pro- and antithrombotic endothelial and non-endothelial factors, factors of coagulation, platelet activation and rheological changes are presented and discussed from positions of Virchow's triad of venous thrombosis. Despite advances in understanding of thrombogenesis in BD, still many issues of diagnosis and targeted preventive and therapeutic measures remain unresolved. Further studies are needed to clarify the pathobiology of BD-related thrombosis and to provide the clinicians with recommendations over the utility, safety and effectiveness of the antithrombotic therapy in BD.

Behçet’s Disease as a Model of Venous Thrombosis

Behçet’s disease (BD) is a chronic inflammatory disease of unknown aetiology characterized by recurrent oral, genital aphthous ulcerations, uveitis, skin lesions and other multisystem affections associated with vasculitis. Different types of vessels, predominantly veins, can be affected in BD. The frequency of vascular lesions in BD, such as superficial and deep venous thromboses, arterial aneurysms and occlusions, ranges between 7-29%.

In this review, various factors of thrombogenesis in BD, particularly pro- and antithrombotic endothelial and non-endothelial factors, factors of coagulation, platelet activation and rheological changes are presented and discussed from positions of Virchow’s triad of venous thrombosis.

Despite advances in understanding of thrombogenesis in BD, still many issues of diagnosis and targeted preventive and therapeutic measures remain unresolved. Further studies are needed to clarify the pathobiology of BD-related thrombosis and to provide the clinicians with recommendations over the utility, safety and effectiveness of the antithrombotic therapy in BD.