Secondary prophylaxis of venous thromboembolism (VTE) with low dose apixaban or rivaroxaban in major-thrombophilia carriers

Direct oral anticoagulants (DOACs) are widely used for treatment and secondary prophylaxis of venous thromboembolism (VTE) and represent the gold standard for VTE secondary prophylaxis, with low-intensity DOACs administration becoming increasingly used worldwide in such scenario. Albeit widespread DOACs usage there are few literature data regarding their efficacy and safety in major thrombophilia carriers and almost no data is available for low intensity apixaban and rivaroxaban as secondary VTE prophylaxis in such patients. The aim of our study is to evaluate and confront the efficacy and safety of low-dose DOACs for VTE secondary prophylaxis, in major thrombophilia carriers vs patients at high risk of VTE recurrence for other reasons. We retrospectively evaluated patients who required long-term anticoagulant secondary prophylaxis to prevent recurrent VTE, treated with apixaban 2.5 mg BID or rivaroxaban 10 mg daily and that were screened for thrombophilia. The examined patients were 339. Baseline characteristics such as sex, age, obesity rate, smoking, number of previous VTEs and comorbidities (such as cardiovascular diseases, diabetes, mild CKD) were equally distributed in either group. The median low-dose DOACs administration time was 19.20 months (IQR 12.17-35.67). During low-dose DOACs treatment, 13 (3.8%) VTE recurrences were observed; 14 bleeding events were registered (4,1%), with no major bleeding (MB), 6 clinically relevant non major bleeding (CRNMB) (1.8%) and 8 minor bleeding (2.3%). No statistically significant difference in the rate of VTE recurrence and/or bleeding events emerged between major thrombophilia carriers and non-major thrombophilia carriers. In multivariate analysis increased risk of VTE recurrence was found for patients with cardiovascular comorbidities (HR 4.00 - p = 0.034) and for patients with more than one previous VTE episode (HR 5.14 - p = 0.034). Our data suggest that low-dose DOACs may be effective and safe in secondary VTE prophylaxis for carriers of major thrombophilia with no increase in VTE recurrence and/or bleeding risk.

Transgender Medicine and Risk of Venous Thromboembolism

Gender dysphoria refers to psychological distress that results from an incongruence between gender identity and sex assigned at birth. Administration of sex hormones is most often used as a first step to develop and maintain physical characteristics consistent with gender identity. Gender-affirming hormone treatment is considered beneficial for the quality of life and reduction of depression. However, estrogen and androgen-lowering hormone therapies used in transwomen are in particular associated with increased risk of venous thromboembolism. In this review, introduced by a clinical case, we provide an overview of the currently available medical therapies in transgender medicine, and put the associated increased risk of venous thromboembolism into perspective.

Risk factors for recurrence during a pregnancy following a first venous thromboembolism: A French observational study

BACKGROUND

Women with a previous venous thromboembolism (VTE) are at risk of recurrence during pregnancy.

OBJECTIVES

We aimed to assess the incidence rate of recurrent VTE during pregnancy, according to the period of pregnancy, and the clinical parameters associated with recurrence, in a prospective cohort of women of childbearing age after a first VTE.

PATIENTS/METHODS

A total of 189 women aged 15-49 years with a first documented VTE were followed until a subsequent pregnancy of at least 20 weeks' gestation between 2000 and 2020. VTE recurrences during pregnancy were recorded, as were potential clinical risk factors for recurrence.

RESULTS

Recurrent VTE occurred in six women during antepartum: five during the first trimester (incidence rate 106.4 per 1000 women-years) (95% confidence interval [CI] 46.3-226.0); none during the second trimester; and one during the third trimester (incidence rate 27.0 per 1000 women-years [95% CI 4.8-138.2]). During postpartum, recurrences occurred in 11 women (incidence rate 212.8 per 1000 women-years [95% CI 119.9-349.1]). These 17 recurrent VTEs presented as pulmonary embolism ± deep vein thrombosis (DVT) in five patients and isolated DVT in 12. Failure of thromboprophylaxis occurred in two cases (33.3%) antepartum and in 10 cases (90.9%) postpartum. In multivariable analysis, only obesity (defined on prepregnancy body mass index) was associated with recurrent VTE (odds ratio 3.34 [95% CI 1.11-10.05, p = .03]).

CONCLUSIONS

This study confirms a high risk of recurrent VTE postpartum, despite thromboprophylaxis, in women with a previous VTE. Only obesity was associated with VTE recurrence during pregnancy, suggesting that low-dose anticoagulation might not be appropriate in obese pregnant women.

The Impact of Direct Oral Anticoagulant Prophylaxis for Thromboembolism in Thrombophilic Patients Undergoing Abdominoplastic Surgery

Congenital or acquired thrombophilia is observed in 10–15% of the general population; therefore, careful screening is carried out in patients at higher risk of venous thrombo-embolism (VTE). High risk of VTE is a contraindication in patients undergoing abdominoplasty. We evaluated rivaroxaban, an oral Xa inhibitor, with enoxaparin, a subcutaneously low molecular weight heparin (LMWH), in 48 female patients with documented thrombophilia, undergoing thrombo-prophylaxis after abdominoplasty. Patients were stratified into two groups according to thrombo-prophylaxis procedure: enoxaparin Group (n = 28) and rivaroxaban Group (n = 20). Hematologic outcomes were evaluated including VTE and hematoma. No episodes of VTE occurred in both groups; two patients during their course of enoxaparin presented severe hematoma for drainage and hemostasis revision. This study suggests that abdominoplasty, in patients with thrombophilia, in combination with thrombo-prophylaxis can be performed safely. Rivaroxaban was as effective as LMWH for preventing VTE, with only a moderate risk of clinically relevant bleeding. More research is needed to determine the optimal timing and duration of prophylaxis in patients undergoing plastic surgery.

Rapid identification of a pathogenic variant of PROS1 in a thrombophilic family by whole exome sequencing: A case report

RATIONALE

Venous thrombosis remains a significant problem in modern days. Genetic factors contribute to a subset of patients with venous thrombosis. It is sometimes challenging to identify the underlying culprit in thrombophilic individuals based on traditional laboratory testing and Sanger sequencing.

PATIENT CONCERNS

A thrombophilic family presented with multiple venous thrombosis was examined.

DIAGNOSES

Molecular genetic analysis revealed a pathogenic missense variant of the PROS1 gene. Based on this finding and clinical manifestations, a final diagnosis of protein S deficiency was made.

INTERVENTIONS

Whole exome sequencing (WES) of the proband was performed to identify disease-causing variants. Subsequently, Sanger sequencing was performed to validate the variant in the affected members.

OUTCOMES

Using WES, we rapidly identified a proven pathogenic missense variant (c.1543C > T, p.Arg515Cys) in the sex hormone-binding globulin domain of PROS1, which was confirmed by Sanger sequencing. The decreased level and activity of protein S caused by the variant explained the phenotypes of the family. Patients received rivaroxaban as a long-term anticoagulation therapy and achieved a good prognosis.

LESSONS

Our study suggests WES as a rapid search strategy to identify the genetic factors underlying thrombophilic disorders. Patients with venous thrombosis caused by PROS1 mutations could receive rivaroxaban as the first choice of anticoagulation therapy.

Long-term recurrence risk after a first venous thromboembolism in men and women under 50 years old: A French prospective cohort

BACKGROUND

Data on long-term venous thromboembolism (VTE) recurrence risk according to gender are conflicting.

OBJECTIVE

To evaluate long-term VTE recurrence risk after a first VTE in men and women under 50 years old.

METHODS

Since May 2000, 875 consecutive patients (315 men, 560 women) with a first symptomatic VTE under 50 years old were enrolled in a French prospective multicentre cohort study and were followed up as long as possible. The primary outcome was symptomatic recurrent VTE during follow-up.

RESULTS

At baseline, men were older and had more comorbidities than women. First VTE was mainly unprovoked in men (80.6%) and hormone-related in women (84.3%). During a median follow-up of 7.0 years (inter-quartile range, 5.0-11.0), recurrent VTE occurred in 97 men (30.8%) and in 72 women (12.9%) (annual incidence rates of recurrent VTE of 4.8% versus 1.8%-person-years, P<0.001). However, there was no difference according to gender in subgroups of patients with a first unprovoked VTE (5.8% versus 3.8%-person-years, P = 0.09). In women, duration of hormonal treatment before first VTE did not influence recurrence risk. In multivariable analysis, unprovoked VTE and family history of VTE were independently associated with recurrence (hazard ratio of 2.50 (95% confidence interval, 1.61 to 3.85) and 1.52 (1.11 to 2.09) respectively).

LIMITATIONS

Number of women with unprovoked VTE was low.

CONCLUSIONS

In patients with a first VTE under 50 years old, a first unprovoked episode and a family history of VTE, but not gender, were associated with a high risk of long-term recurrence.

Pulmonary embolism: update on management and controversies

Pulmonary embolism is a common and potentially fatal cardiovascular disorder that must be promptly diagnosed and treated. The diagnosis, risk assessment, and management of pulmonary embolism have evolved with a better understanding of efficient use of diagnostic and therapeutic options. The use of either clinical probability adjusted or age adjusted D-dimer interpretation has led to a reduction in diagnostic imaging to exclude pulmonary embolism. Direct oral anticoagulation therapies are safe, effective, and convenient treatments for most patients with acute venous thromboembolism, with a lower risk of bleeding than vitamin K antagonists. These oral therapeutic options have opened up opportunities for safe outpatient management of pulmonary embolism in selected patients. Recent clinical trials exploring the use of systemic thrombolysis in intermediate to high risk pulmonary embolism suggest that this therapy should be reserved for patients with evidence of hemodynamic compromise. The role of low dose systemic or catheter directed thrombolysis in other patient subgroups is uncertain. After a diagnosis of pulmonary embolism, all patients should be assessed for risk of recurrent venous thromboembolism to guide duration of anticoagulation. Patients with a venous thromboembolism associated with a strong, transient, provoking risk factor can safely discontinue anticoagulation after three months of treatment. Patients with an ongoing strong risk factor, such as cancer, or unprovoked events are at increased risk of recurrent events and should be considered for extended treatment. The use of a risk prediction score can help to identify patients with unprovoked venous thromboembolism who can benefit from extended duration therapy. Despite major advances in the management of pulmonary embolism, up to half of patients report chronic functional limitations. Such patients should be screened for chronic thromboembolic pulmonary hypertension, but only a small proportion will have this as the explanation of their symptoms. In the remaining patients, future studies are needed to understand the pathophysiology and explore interventions to improve quality of life.

The Rate of Venous Thromboembolism Before and After Spine Surgery as Determined with Indirect Multidetector CT

BACKGROUND

This prospective cohort study investigated the rate of venous thromboembolism (VTE) before and after spine surgery as determined with use of indirect multidetector computed tomography (MDCT).

METHODS

We performed a prospective study of 105 patients (36 women and 69 men ranging in age from 38 to 88 years) undergoing spine surgery at 2 institutions. Indirect MDCT was performed before and 3 days after surgery. Patients with a history of dialysis or drug allergy to contrast medium were excluded.

RESULTS

No patient had symptomatic VTE preoperatively or postoperatively. The preoperative and postoperative rates of asymptomatic VTE were 4.8% and 13.0%, respectively; the rates of asymptomatic pulmonary embolism were 2.9% and 8.0%, respectively; and the rates of asymptomatic deep venous thrombosis were 3.8% and 6.0%, respectively. Age, sex, height, weight, body mass index, operative time, volume of intraoperative blood loss, and specific comorbidities (diabetes, hypertension, cardiac disease, previous VTE, and previous anticoagulation treatment) were not found to be risk factors.

CONCLUSIONS

Our findings demonstrated a low rate of preoperative VTE but a high rate of postoperative VTE in association with spine surgery. Surgeons need to be aware of the risk of VTE in patients undergoing spine surgery. MDCT is an effective and convenient technology for the early detection of VTE in such patients.

LEVEL OF EVIDENCE

Prognostic Level I. See Instructions for Authors for a complete description of levels of evidence.

Genetics of Venous Thrombosis: update in 2015

Venous thrombosis (VT) is a common multifactorial disease with a genetic component that was first suspected nearly 60 years ago. In this review, we document the genetic determinants of the disease, and update recent findings delivered by the application of high-throughput genotyping and sequencing technologies. To date, 17 genes have been robustly demonstrated to harbour genetic variations associated with VT risk: ABO, F2, F5, F9, F11, FGG, GP6, KNG1, PROC, PROCR, PROS1, SERPINC1, SLC44A2, STXBP5, THBD, TSPAN15 and VWF. The common polymorphisms are estimated to account only for a modest part (~5 %) of the VT heritability. Much remains to be done to fully disentangle the exact genetic (and epigenetic) architecture of the disease. A large suite of powerful tools and research strategies can be deployed on the large collections of patients that have already been assembled (and additional are ongoing).

Family history of venous thromboembolism as a risk factor and genetic research tool

Familial clustering of venous thromboembolism (VTE) was described as far back as 1905 by Briggs. Although Egeberg discovered inherited deficiency of antithrombin in 1965, it was not until Dahlback discovered resistance to activated protein C in 1993 that it became clear that genetic factors are common risk factors of VTE. Several genes have been linked to familial aggregation of VTE and genome-wide association studies have found several novel gene loci. Still, it has been estimated that much of the heritability for VTE remains to be discovered. Family history (FH) of VTE is therefore still important to determine whether a patient has an increased genetic risk of VTE. FH has the potential to represent the sum of effects and interactions between environmental and genetic factors. In this article the design, methodology, results, clinical and genetic implications of FH studies of VTE are reviewed. FH in first-degree relatives (siblings and/or parents) is associated with a 2–3 times increased familial relative risk (FRR). However, the FRR is dependent on age, number of affected relatives, and presentation of VTE (provoked/unprovoked). Especially high familial risks are observed in individuals with two or more affected siblings (FFR> 50). However, the familial risk for recurrent VTE is much lower or non-significant. Moreover, FH of VTE appears mainly to be important for venous diseases (i. e. VTE and varicose veins). The familial associations with other diseases are weaker. In conclusion, FH of VTE is an important research tool and a clinically potential useful risk factor for VTE.

Determination of age-specific and sex-specific familial risks for the different manifestations of venous thromboembolism: A nationwide family study in Sweden

This nationwide study aimed to determine whether differences exist in age-specific and sex-specific familial risks for pulmonary embolism (PE), venous thrombosis of the lower limbs (VT) and other forms of venous thromboembolism (OVTE) among offspring, siblings and spouses of affected individuals. The Swedish Multi-Generation Register was linked to the Hospital Discharge Register data for the period 1987–2007. Standardised incidence ratios (SIRs) were calculated for individuals whose relatives were hospitalised for venous thromboembolism (VTE), as determined by the International Classification of Diseases (ICD), and those whose relatives were unaffected by VTE. The total number of hospitalised VTE patients was 45,362. All VTE patients were categorised as PE, VT or OVTE according to ICD at first hospitalisation. For example, the parental SIRs for PE, VT and OVTE in offspring at age 10–19 years were 2.89 (95% CI 1.48–5.06), 4.99 (95% CI 3.22–6.10) and 3.89 (95% CI 2.51–5.75), respectively. The low spousal risks of PE (1.08; 95% CI 1.02–1.13), VT (1.06; 95% CI 1.011.12) and OVTE (1.07; 95% CI 1.00–1.15) suggest the familial risks to be largely genetic. In both men and women, familial relative risks were increased for all the different manifestations of VTE with the exception of those older than 70 years. Familial history is a risk indicator in both sexes, and is potentially useful for clinical risk assessment for the different manifestations of VTE.

The prevalence and clinical manifestation of hereditary thrombophilia in Korean patients with unprovoked venous thromboembolisms

Background

Hereditary thrombophilia (HT) is a genetic predisposition to thrombosis. Asian mutation spectrum of HT is different from Western ones. We investigated the incidence and clinical characteristics of HT in Korean patients with unprovoked venous thromboembolism (VTE).

Methods

Among 369 consecutive patients with thromboembolic event who underwent thrombophilia tests, we enrolled 222 patients diagnosed with unprovoked VTE. The presence of HT was confirmed by DNA sequencing of the genes that cause deficits in natural anticoagulants (NAs). Median follow-up duration was 40±38 months.

Results

Among the 222 patients with unprovoked VTE, 66 (29.7%) demonstrated decreased NA level, and 33 (14.9%) were finally confirmed to have HT in a genetic molecular test. Antithrombin III deficiency (6.3%) was most frequently detected, followed by protein C deficiency (5.4%), protein S deficiency (1.8%), and dysplasminogenemia (1.4%). The HT group was significantly younger (37 [32–50] vs. 52 [43–65] years; P < 0.001) and had a higher proportion of male (69.7% vs. 47%; P = 0.013), more previous VTE events (57.6% vs. 31.7%; P = 0.004), and a greater family history of VTE (43.8% vs. 1.9%; P < 0.001) than the non-HT group. Age <45 years and a family history of VTE were independent predictors for unprovoked VTE with HT (odds ratio, 9.435 [2.45–36.35]; P = 0.001 and 92.667 [14.95–574.29]; P < 0.001).

Conclusions

About 15% of patients with unprovoked VTE had HT. A positive family history of VTE and age <45 years were independent predictors for unprovoked VTE caused by HT.

The use of direct oral anticoagulants in inherited thrombophilia

To review the use of the direct oral anticoagulant (DOAC) agents in inherited thrombophilia based on the literature. MEDLINE, International Pharmaceutical Abstracts, and Google Scholar searches (1970-May 2016) were conducted for case reports, case series, retrospective cohorts, or clinical trials using the key words: protein C deficiency, protein S deficiency, antithrombin deficiency, activated protein C resistance, Factor V Leiden, hypercoagulable, NOACs, dabigatran, apixaban, rivaroxaban, betrixaban, edoxaban, Xa inhibitor, direct thrombin inhibitor. Results were limited to English-only articles. Clinical studies evaluating the use of DOACs for hypercoagulable states related to inherited thrombophilia were selected and evaluated. Thrombophilia, a predisposition to thrombosis, manifests predominantly as venous thromboembolism. Causes of inherited thrombophilia include antithrombin deficiency, deficiencies of proteins C and S, and Factor V Leiden mutation. Many patients with thrombophilia receive anticoagulant therapy for primary or secondary prevention of VTE, historically either warfarin or a heparin product. DOAC's have been considered as potential alternatives to traditional agents based on their pharmacologic activity. Case reports and a post-hoc analysis of a clinical trial have indicated positive results in patients with inherited thrombophilia and VTE. Positive results have been reported for the use of DOACs in inherited thrombophilia. Further robust studies are needed for definitive decision making by clinicians.

Risk indicators for venous thrombosis in first-degree relatives of patients with recurrent venous thromboembolism in Chinese

Having encountered several subjects with venous thromboembolism (VTE) in 1 family in which 1 proband has recurrent VTE (rVTE), we aimed to assess the risk of VTE in first-degree relatives, especially the children of individuals with rVTE, and to investigate the association of endothelial nitric oxide synthase (eNOS) G894T polymorphism between Chinese persons with rVTE and their offspring.We collected information about family histories and blood samples from 126 individuals with rVTE who had presented to our institute from 2003 to 2014, and 126 population-based controls and the first-degree relatives of subjects in these 2 groups. We tested blood samples for heritable thrombophilia and calculated odds ratios (ORs) and kappa coefficients.First-degree relatives of individuals with rVTE patients had a statistically significant risk of developing VTE (OR 2.62, 95% confidence interval [CI] 1.61-4.26, P < 0.001). For siblings, the OR was 2.72 (95% CI 1.56-4.73, P < .001). Moreover, for each year that the patient was older, the OR was 0.98 (95% CI 0.97-0.99, P = 0.03). One (11.2%) of the 9 individuals who had the same eNOS G894T polymorphism as their probands had a history of VTE, whereas none of the 17 relatives without the same polymorphism had developed VTE. The associations between patients and their children were statistically significant for VTE (kappa = 0.23, P < 0.001) and for eNOS G894T (kappa = 0.03, P = 0.04).In this case-controlled study, we demonstrated a higher risk of VTE among first-degree relatives of individuals with rVTE, especially in siblings of younger subjects with rVTE. We also found that eNOS G894T polymorphism may be a predictor of VTE in offspring of individuals with rVTE.

A Qualitative Study to Appraise Patients and Family Members Perceptions, Knowledge, and Attitudes towards Venous Thromboembolism Risk

Objective

This study aimed to examine perception, knowledge and concerns developed by patients and their family as regards venous thromboembolism (VTE) risk.

Methods

We conducted a qualitative study. Participants were: (1) patients with unprovoked VTE with either factor V Leiden mutation or G20210A prothrombin gene mutation or not; and (2) their first-degree relatives. Interviews took place mostly at Brest University Hospital. Participants produced narratives of the patient’s illness, stressing their perception of the disorder, its mechanisms, etiology, circumstances and risk factors. Interviews were audiotaped and transcribed verbatim. On an ongoing basis, central themes were identified and data from narratives were categorized by these themes.

Results

A total of ten patients and 25 first-degree relatives were interviewed. Analyses of patient’s narratives suggested 4 main themes: (1) concerns about initial symptoms and suspicion of VTE. The longer the duration of the initial phase, the more likely anxiety took place and persisted after diagnosis; (2) underestimation of potential life-threatening episode once being managed in emergency; (3) possible biographical disruption with inability to cope with the event; and (4) secondary prevention attitudes motivated by remains of the episode and favoring general prevention attitudes. Analyses of the first-degree relatives narratives suggested 3 main themes: (1) common interpretation of the VTE episode shared within the family; (2) diverse and sometimes confusing interpretation of the genetic status; and, (3) interpretation of clinical signs linked to VTE transmission within the family.

Conclusions

Construction of the risk of VTE is based on patient’s initial experience and shared within the family. Collection of narratives illustrates the gap between these perceptions and current medical knowledge. These results support the need to collect the perceptions of the VTE episode and its consequences, as a prerequisite to any health education process.

Venous thromboembolism and varicose veins share familial susceptibility: a nationwide family study in Sweden

Background

Varicose veins (VVs) have been associated with venous thromboembolism (VTE), but whether these diseases share familial susceptibility has not been determined. This nationwide study aimed to determine whether VTE shares familial susceptibility with VVs.

Methods and Results

Swedish Multigeneration Register data for persons aged 0 to 76 years during the period 1964–2008 were linked to the Swedish Inpatient and Outpatient Registers. Familial risks (standardized incidence ratios [SIRs]) of VTE and VVs were examined in 2 ways (ie, bidirectionally): risk of VTE in subjects whose siblings had been diagnosed with VVs and risk of VVs in persons whose siblings had been diagnosed with VTE. The analyses were repeated for spouses to determine the importance of shared adult family environment. In total, 96 810 siblings had VVs and 87 564 had VTE. An increased risk of VTE was observed in persons whose siblings had VVs (SIR 1.30, 95% CI 1.26 to 1.33), whereas persons whose siblings had VTE had an increased risk of VVs (SIR 1.30, 95% CI 1.27 to 1.34). If 2 or more siblings were affected by VTE, the risk for VVs was 1.70 (95% CI 1.53 to 1.88). Conversely, if 2 or more siblings were affected by VVs, the risk for VTE was 1.52 (95% CI 1.38 to 1.67). In spouses of VTE patients, a minor increased risk of VVs was observed (SIR 1.05 for husbands, SIR 1.06 for wives). The risk of VTE in spouses of VV patients was similarly small (SIR 1.01 for husbands, SIR 1.05 for wives).

Conclusions

VVs and VTE share familial susceptibility. This novel finding suggests the existence of shared familial and possibly genetic factors.

Factors that predict thrombosis in relatives of patients with venous thromboembolism

When counseling first-degree relatives of patients with venous thromboembolism (VTE), it is important to know whether factors other than thrombophilia influence their risk for thrombosis. We assessed the risk for VTE in 915 first-degree relatives of patients with provoked VTE, compared this with the risk in 1752 first-degree relatives of patients with unprovoked VTE, and then combined data from the 2 groups of relatives to identify predictors of thrombosis. There had been 123 VTEs in 2617 first-degree relatives (0.12 per 100 person-years). The risk for VTE in first-degree relatives was higher if the index cases had an unprovoked compared with a provoked VTE (odds ratio [OR], 2.38; 95% confidence interval [CI], 1.43-3.85), if the index case was younger (OR, 0.97 per year older; 95% CI, 0.96-0.99), and if an additional family member had VTE (OR, 2.71; 95% CI, 2.22-3.31). Among first-degree relatives of an index case with factor V Leiden or the prothrombin 20210A gene variant, the presence of these abnormalities also predicted thrombosis (OR, 4.42; 95% CI, 1.35-14.38). We conclude that thrombosis at a young age and unprovoked VTE predict VTE in first-degree relatives, and that the influence of these 2 factors is additive.

Familial Transmission of Venous Thromboembolism

Background—

Venous thromboembolism (VTE) clusters in families, but the familial risk of VTE has not been determined among adoptees. The aim was to disentangle the contributions of genetic and environmental factors to the familial transmission of VTE.

Methods and Results—

The Swedish Multi-Generation Register was used to follow all Swedish-born adoptees born from 1932 to 2004 (n=80,214) between January 1, 1964, and December 31, 2010, for VTE. The risk of VTE was estimated in adoptees with ≥1 biological parent with VTE compared with adoptees without a biological parent with VTE. The risk of VTE was also estimated in adoptees with ≥1 adoptive parent with VTE compared with adoptees without an adoptive parent with VTE. Adoptees with ≥1 biological parent with VTE (n=137) were more likely to have VTE than adoptees without a biological parent with VTE (standardized incidence ratio) 1.51 (95% confidence interval, 1.27–1.79). The standardized incidence ratio for VTE was highest for adoptees with a biological parent diagnosed with VTE before the age of 50 years (standardized incidence ratio=2.03, 1.24–3.14). In contrast, adoptees with ≥1 adoptive parent with VTE (n=156) were not at increased risk of VTE (standardized incidence ratio=1.07, 0.91–1.25).

Conclusions—

These novel findings suggest that genetic factors make a stronger contribution to the familial transmission of VTE from parents to offspring than family environmental factors.

Family history of venous thromboembolism (VTE) and risk of recurrent hospitalization for VTE: a nationwide family study in Sweden

BACKGROUND

Data concerning the importance of a family history of venous thromboembolism (VTE) for the risk of recurrent VTE are sparse. The aim of this nationwide study was to determine whether a family history of VTE is a risk factor for recurrent hospitalization for unprovoked VTE (deep vein thrombosis of the lower extremities or pulmonary embolism).

METHODS

We linked Multigeneration Register data on individuals aged 0-77 years to the Swedish nationwide Hospital Discharge Register data for the period 1987-2009 to compare the risk of hospitalization for unprovoked recurrent VTE among individuals with and without a parental or sibling history of VTE. We calculated hazard ratios (HRs) to determine the familial HR for recurrent hospitalization for VTE.

RESULTS AND CONCLUSIONS

The risk of recurrent VTE hospitalization was 1.20 (95% confidence interval [CI] 1.10-1.32) for individuals with affected parents, and 1.30 (95% CI 1.14-1.49) for those with affected siblings. The risk of recurrent VTE hospitalization in individuals with two affected parents was 1.92 (95% CI 1.44-2.58). There was an interaction between age at diagnosis of VTE and a family history of VTE, with a family history having a stronger effect on VTE risk in younger patients. We conclude that a family history of VTE is a modest risk factor for recurrent VTE hospitalization in Sweden.

Age-and sex-specific seasonal variation of venous thromboembolism in patients with and without family history: a nationwide family study in Sweden

Seasonal variation in venous thromboembolism (VTE) risk in individuals with familial predisposition to VTE has not been explored. This nationwide study aimed to determine whether there are age- and sex-specific seasonal differences in risk of hospitalisation of VTE among individuals with and without a family history of VTE. The Swedish Multi-Generation Register was linked to Hospital Discharge Register data for the period 1964-2010. Seasonal variation in first VTE events in 1987-2010 for individuals with and without a family history of VTE (siblings or parents) was determined by several independent methods. Stratified analyses were performed according to age, sex, and VTE subtype (pulmonary embolism [PE] or deep venous thrombosis [DVT]). Seasonal variation in VTE incidence, mostly with a peak during the winter, was observed in both sexes in individuals with and without family history with overall peak-to-low ratios (PLRs) of 1.15 and 1.21, respectively. The peak day was December 25 and February 1 for those with and without a family history of VTE, respectively. Seasonal variation was strongest among individuals aged >50 years. Among individuals aged 0-25 years with a family history, the peak for VTE was in July (PLR = 1.20). Significant seasonal variation was observed for PE and DVT with the exception of DVT among those with a family history (PLR = 1.01). In conclusion, our data support the presence of a modest seasonal variation of VTE among individuals with and without a family history of VTE. However, young age and family history may modify and attenuate the effect of season on VTE.

Familial risk of venous thromboembolism in first-, second- and third-degree relatives: a nationwide family study in Sweden

Venous thromboembolism (VTE) clusters in families, but the familial risk of VTE has only been determined in first-degree relatives. This nationwide study aimed to determine the familial risk of VTE in first-, second- and third-degree relatives of affected individuals. The Swedish Multi-Generation Register was linked to Hospital Discharge Register data for the period 1987-2009. This was a case-cohort study. Odds ratios (ORs) for VTE were calculated for individuals whose relatives were hospitalised for VTE, as determined by the International Classification of Diseases (ICD), and those whose relatives were unaffected by VTE. The familial OR for VTE was 2.49 in siblings (95% confidence interval [CI] 2.40-2.58), 2.65 in children (2.50-2.80), 2.09 in parents (2.03-2.15), 1.52 in maternal half-siblings (1.26-1.85), 2.34 in paternal half-siblings (2.00-2.73), 1.69 in nieces/nephews (1.57-1.82), 1.47 in cousins (1.33-1.64), and 1.14 in spouses of individuals diagnosed with VTE (1.09-1.18). Familial clustering was stronger at young ages. The familial transmission was slightly stronger for males compared with females but was only significant for siblings 1.13 (1.05-1.22) and parents 1.11 (1.05-1.78) of probands. The present data showing an increased VTE risk among not only first-degree relatives but also second- and third-degree relatives indicate that the genetic component of the familial clustering of VTE is strong. Family history is a potentially useful genetic surrogate marker for clinical VTE risk assessment, even in second- and third degree-relatives.

Inherited thrombophilia in children with venous thromboembolism and the familial risk of thromboembolism: an observational study

Screening for inherited thrombophilia (IT) is controversial; persons at high risk for venous thromboembolism (VTE) who benefit from screening need to be identified. We tested 533 first- and second-degree relatives of 206 pediatric VTE patients for IT (antithrombin, protein C, protein S, factor V G1691A, factor II G20210A) and determined the incidence of symptomatic VTE relative to their IT status. The risk for VTE was significantly increased among family members with, versus without, IT (hazard ratio = 7.6; 95% confidence interval [CI], 4.0-14.5; P < .001) and highest among carriers of antithrombin, protein C, or protein S deficiency (hazard ratio = 25.7; 95% CI, 12.2-54.2; P < .001). Annual incidences of VTE were 2.82% (95% CI, 1.63%-4.80%) among family members found to be carriers of antithrombin, protein C, or protein S deficiency, 0.42% (0.12%-0.53%) for factor II G202010A, 0.25% (0.12%-0.53%) for factor V G1691A, and 0.10% (0.06%-0.17%) in relatives with no IT. Given the high absolute risk of VTE in relatives with protein C, protein S, and antithrombin deficiency, we suggest screening for these forms of hereditary thrombophilia in children with VTE and their relatives. Interventional studies are required to assess whether thromboembolism can be prevented in this high-risk population.

Hereditary thrombophilia in Korean patients with idiopathic pulmonary embolism

PURPOSE

Hereditary thrombophilia (HT) is a major risk factor for idiopathic pulmonary embolism (iPE) and shows different prevalence among ethnic groups. The prevalence and clinical characteristics of HT in Korean patients with iPE were investigated.

MATERIALS AND METHODS

Patients with PE on computed tomography (CT) scan were recruited, and those with malignancy were excluded. Patients were divided into iPE and provoked PE (pPE) groups. The presence of HT in the iPE group was assessed by DNA sequencing of the corresponding gene in patients who had low levels of natural anticoagulants. The clinical characteristics of iPE with HT (iPE/HT+) were compared with those of iPE without HT (iPE/HT-) and pPE.

RESULTS

Out of 161 patients, 84 patients had iPE and 77 patients had pPE. Among 54 patients in the iPE group whose coagulation profiles were tested, 28 patients were diagnosed with HT (51.9%; 28/54). Compared with the iPE/HT- and pPE groups, the iPE/HT+ group showed the highest proportion of male patients (71.4%; p<0.001); the youngest mean age (44±14 years; p<0.001); and the highest frequencies for history of venous thromboembolism (64.3%; p<0.001), concurrent deep vein thrombosis (75.0%; p=0.021), and adverse clinical outcomes (42.9%, p<0.001). Protein C deficiency was the most common HT. On molecular genetic tests, causative mutation was identified in 13 patients.

CONCLUSION

In this study of Korean patients, about half of the patients with iPE had HT. Patients with iPE and HT were mostly young males with deep venous thrombosis (DVT), previous venous thromboembolism (VTE), and frequent adverse clinical outcomes. Therefore, Korean patients with iPE should be tested for HT.

A nationwide family study of pulmonary embolism: identification of high risk families with increased risk of hospitalized and fatal pulmonary embolism

BACKGROUND

Family history is an important risk factor for deep venous thrombosis. However, few studies have determined the importance of family history of pulmonary embolism (PE).

OBJECTIVE

This nationwide study aimed to determine the familial risks of fatal and hospitalized PE.

METHODS

The Swedish Multi-Generation Register for subjects aged 0 to 76 years old born since 1932 were linked to the Hospital Discharge Register and Cause of Death Register for the period 1964-2008. Standardized incidence ratios (SIRs) for first hospitalization or death (without previous hospitalization for PE) with a main diagnosis of PE were calculated for individuals whose parent or siblings were hospitalized with or died from PE, compared to those whose parent or siblings were not affected by PE.

RESULTS

A total of 20,860 individuals were hospitalized for PE and 862 died due to primary fatal PE (without previous hospitalization for PE). The familial SIR for individuals with one sibling with hospitalized PE was 2.49 (95% CI 1.62-3.83). The familial SIR for siblings with two affected probands was 114.29 (95% CI 56.57-223.95). The familial SIRs for individuals with a parent or sibling hospitalized for PE were significantly increased for fatal PE (1.76; 95% CI 1.38-2.21) and hospitalized PE (2.13; 95% CI 2.04-2.23). Spouses had low overall familial risk for PE (1.09; 95% CI, 1.03-1.14).

CONCLUSION

The high familial risk in multiplex sibling families suggests the existence of strong genetic risk factors for PE. Familial factors and possibly genetic factors are important risk factors for primary fatal pulmonary embolism.

Incidence and Risk Factors of the Post-thrombotic Syndrome

Annually 1–2 in every 1000 adults will develop a deep venous thrombosis of the lower extremity. A third to half of these patients will develop the post-thrombotic syndrome (PTS). However, predicting which patients will develop the PTS remains elusive. Ipsilateral thrombosis recurrence seems to be the most important risk factor. Moreover, residual venous occlusion and valvular reflux seem to predict PTS incidence to some degree. Laboratory parameters, including D-dimers and inflammatory markers, have shown promise in predicting development of the PTS in patients and are currently under investigation. Creating a model based on all combined risk factors and patient characteristics might aid in risk stratification in individual patients.

Development and validation of risk prediction algorithm (QThrombosis) to estimate future risk of venous thromboembolism: prospective cohort study

OBJECTIVES

To derive and validate a new clinical risk prediction algorithm (QThrombosis, www.qthrombosis.org) to estimate individual patients' risk of venous thromboembolism.

DESIGN

Prospective open cohort study using routinely collected data from general practices. Cox proportional hazards models used in derivation cohort to derive risk equations evaluated at 1 and 5 years. Measures of calibration and discrimination undertaken in validation cohort.

SETTING

564 general practices in England and Wales contributing to the QResearch database.

PARTICIPANTS

Patients aged 25-84 years, with no record of pregnancy in the preceding 12 months or any previous venous thromboembolism, and not prescribed oral anticoagulation at baseline: 2,314,701 in derivation cohort and 1,240,602 in validation cohort. Outcomes Incident cases of venous thromboembolism, either deep vein thrombosis or pulmonary embolism, recorded in primary care records or linked cause of death records.

RESULTS

The derivation cohort included 14,756 incident cases of venous thromboembolism from 10,095,199 person years of observation (rate of 14.6 per 10,000 person years). The validation cohort included 6913 incident cases from 4,632,694 person years of observation (14.9 per 10,000 person years). Independent predictors included in the final model for men and women were age, body mass index, smoking status, varicose veins, congestive cardiac failure, chronic renal disease, cancer, chronic obstructive pulmonary disease, inflammatory bowel disease, hospital admission in past six months, and current prescriptions for antipsychotic drugs. We also included oral contraceptives, tamoxifen, and hormone replacement therapy in the final model for women. The risk prediction equation explained 33% of the variation in women and 34% in men in the validation cohort evaluated at 5 years The D statistic was 1.43 for women and 1.45 for men. The receiver operating curve statistic was 0.75 for both sexes. The model was well calibrated.

CONCLUSIONS

We have developed and validated a new risk prediction model that quantifies absolute risk of thrombosis at 1 and 5 years. It can help identify patients at high risk of venous thromboembolism for prevention. The algorithm is based on simple clinical variables which the patient is likely to know or which are routinely recorded in general practice records. The algorithm could be integrated into general practice clinical computer systems and used to risk assess patients before hospital admission or starting medication which might increase the risk of venous thromboembolism.

Familial risks of unusual forms of venous thrombosis: a nationwide epidemiological study in Sweden

OBJECTIVE

This is the first nationwide study to determine familial risks of unusual forms of venous thrombosis amongst offspring of affected parents and amongst siblings.

DESIGN AND SETTINGS

The Swedish Multigeneration Register of 0- to 75-year-old subjects was linked to the Hospital Discharge Register for the period 1987-2007. Standardized incidence ratios (SIRs) were calculated for individuals whose relatives were hospitalized for venous thromboembolism (VTE), as determined by the International Classification of Diseases, compared to those whose relatives were not affected by VTE.

RESULTS

The total number of hospitalized patients with VTE was 45 362, of which 1824 (4.0%) were affected by a rare thrombotic condition. The familial SIRs in cases with a history of VTE in parents or siblings were significantly increased for migrating thrombophlebitis (1.81; 95% confidence interval (CI) 1.40-2.31), portal vein thrombosis (2.35; 95% CI 1.77-3.06), vena cava thrombosis (1.96; 95% CI 1.42-2.64) and cerebral venous thrombosis (1.74; 95% CI 1.30-2.28). Budd-Chiari syndrome (SIR, 0.92; 95% CI 0.24-2.38) and renal vein thrombosis (SIR, 1.72; 95% CI 0.62-3.77) were not significantly associated with parental or sibling history of VTE; however, these two conditions were very rare, and therefore, we cannot draw any definite conclusions from this finding.

CONCLUSIONS

Family history is an important risk factor for most unusual forms of VTE. Moreover, even the paraneoplastic phenomenon, migrating thrombophlebitis (Trousseau's syndrome), is associated with a family history of VTE. Thus, our data suggest that most rare forms of VTE have a familial background.

Parental history and venous thromboembolism: a nationwide study of age-specific and sex-specific familial risks in Sweden

BACKGROUND

The value of parental history as a risk indicator for venous thromboembolism (VTE) has not been determined in a nationwide setting.

OBJECTIVES

To perform the first nationwide study of age-specific and sex-specific familial VTE risks in offspring of parents hospitalized for VTE.

PATIENTS/METHODS

The Swedish Multigeneration Register of 0-75-year-old subjects was linked to the Hospital Discharge Register for 1987-2007. Standardized incidence ratios (SIRs) were calculated for individuals whose parents were hospitalized for VTE as compared with those whose parents were unaffected.

RESULTS

Among 45,362 hospitalized offspring cases with VTE, 4865 offspring of affected parents were identified with a familial SIR of 2.00 (95% confidence interval [CI] 1.94-2.05). Familial SIR was slightly higher for male offspring than for female offspring (2.08, 95% CI 2.00-2.16 vs. 1.91, 95% CI 1.84-1.99). The risk in offspring was further increased when both parents were affected (3.97, 95% CI 3.40-4.61), with high familial risks at ages 20-29 years (10.00, 95% CI 5.91-15.84). The familial risks for VTE among offspring were increased from the age of 10 years up to 75 years, with familial SIRs of 3.96 (95% CI 3.13-4.94) at age 10-19 years and 1.48 (95% CI 1.17-1.84) at ages 70-75 years. However, the absolute incidence rate increased with age.

CONCLUSIONS

Parental history is potentially useful for risk assessments of VTE, although age needs to be considered. Our results support the use of an age-dependent multicausal model to estimate the risk of VTE.

Predictors of thrombosis in relatives of patients with venous thromboembolism

PURPOSE OF REVIEW

Hereditary and acquired risk factors contribute to the development of venous thromboembolism (VTE). Relatives of patients who have a hereditary predisposition to thrombosis ('hereditary thrombophilia') will have a heightened risk of VTE if they share the same thrombophilic abnormality. However, if patients do not have a currently recognized thrombophilia it cannot be assumed that their relatives have a normal risk of thrombosis; the patient and their relatives may have a yet to be discovered hereditary abnormality.

RECENT FINDINGS

A recent study by our group suggests that the relatives of patients with unprovoked VTE at a young age (e.g. <45 years) have a substantially higher risk [odds ratio (OR) 3.3; 95% confidence interval (CI) 1.7-6.4] of developing VTE than the relatives of older patients with unprovoked VTE (e.g. >71 years). This effect occurred independently of whether patients had a currently recognized hereditary thrombophilia.

SUMMARY

Relatives of patients with unprovoked VTE have an increased risk of VTE. Testing for thrombophilia in the patients, and in the relatives of the patients who have a thrombophilia, allows the risk of thrombosis in the relatives to be estimated. Thrombosis at a young age appears to be an additional independent risk factor for a heightened risk of thrombosis in patients' relatives.

Pulmonary thromboembolic disease. Clinical management of acute and chronic disease

Pulmonary thromboembolism falls between the areas of pulmonology and cardiology, internal medicine and intensive care, radiology and nuclear medicine, and hematology and cardiothoracic surgery. Depending on their clinical background, physicians faced with a patient with a pulmonary thromboembolism may speak different languages and adopt different treatment approaches. Now, however, there is an opportunity to end the Tower of Babel surrounding pulmonary thromboembolism. There is a growing acknowledgement that the key clinical problems in both acute pulmonary embolism and chronic thromboembolic pulmonary hypertension are linked to right ventricular pressure overload and right ventricular failure. As a result, cardiologists and cardiac intensive care specialists are taking an increasing interest in understanding and combating these conditions. The European Society of Cardiology was the first to elaborate comprehensive clinical practice guidelines for pulmonary thromboembolism and chronic thromboembolic pulmonary hypertension. The task forces involved in producing these guidelines included radiologists, pulmonologists, hematologists, intensive care physicians and surgeons, which ensured that the final document was universally acceptable. The aim of this article was to provide an overview of the epidemiology, risk factors, diagnosis, treatment, prognosis and prevention of acute pulmonary thromboembolism and chronic thromboembolic pulmonary hypertension, while taking into account European Society of Cardiology guidelines and incorporating new evidence where necessary.