Onset of labor and use of analgesia in women using thromboprophylaxis with 2 doses of low-molecular-weight heparin: insights from the Highlow study.

BACKGROUND: Peripartum management of women using low-molecular-weight heparin (LMWH) varies widely. Minimum time intervals are required between LMWH injection and neuraxial procedure, and they differ by dose. OBJECTIVES: The objective of this study was to describe the onset of labor and use of analgesia in women using LMWH and to compare practices between intermediate-dose and low-dose LMWH. METHODS: In the Highlow study (NCT01828697), 1110 women were randomized to intermediate-dose or low-dose LMWH and were instructed to discontinue LMWH when labor commenced unplanned or 24 hours prior to planned delivery. The required time interval since last injection to receive a neuraxial procedure was ≥24 hours for intermediate-dose LMWH or ≥12 hours for low-dose LMWH. RESULTS: In total, 1018 women had an ongoing pregnancy for ≥24 weeks. Onset of labor was spontaneous in 198 of 509 (39%) women on intermediate-dose LMWH and in 246 of 509 (49%) on low-dose LMWH. With unplanned onset, a neuraxial procedure was performed in 37% on intermediate-dose and in 48% on low-dose LMWH (risk difference -11%, 95% CI -20% to -2%). Based on time interval, 61% on intermediate-dose and 82% on low-dose LMWH were eligible for a neuraxial procedure. With planned onset, 68% on intermediate-dose and 66% on low-dose LMWH received a neuraxial procedure, whereas 81% and 93%, respectively, were eligible for a neuraxial procedure (risk difference -13%, 95% CI -18% to -8%). CONCLUSION: With spontaneous onset of labor, neuraxial procedures were performed less often in women using intermediate-dose LMWH. Irrespective of onset, fewer women on intermediate-dose LMWH than those on low-dose LMWH were eligible for neuraxial procedures based on required time intervals since the last LMWH injection.

Treatment and Long-Term Clinical Outcomes of Incidental Pulmonary Embolism in Patients With Cancer: An International Prospective Cohort Study.

PURPOSE: Pulmonary embolism is incidentally diagnosed in up to 5% of patients with cancer on routine imaging scans. The clinical relevance and optimal therapy for incidental pulmonary embolism, particularly distal clots, is unclear. The aim of the current study was to assess current treatment strategies and the long-term clinical outcomes of incidentally detected pulmonary embolism in patients with cancer. PATIENTS AND METHODS: We conducted an international, prospective, observational cohort study between October 22, 2012, and December 31, 2017. Unselected adults with active cancer and a recent diagnosis of incidental pulmonary embolism were eligible. Outcomes were recurrent venous thromboembolism, major bleeding, and all-cause mortality during 12 months of follow-up. Outcome events were centrally adjudicated. RESULTS: A total of 695 patients were included. Mean age was 66 years and 58% of patients were male. Most frequent cancer types were colorectal (21%) and lung cancer (15%). Anticoagulant therapy was initiated in 675 patients (97%), of whom 600 (89%) were treated with low-molecular-weight heparin. Recurrent venous thromboembolism occurred in 41 patients (12-month cumulative incidence, 6.0%; 95% CI, 4.4% to 8.1%), major bleeding in 39 patients (12-month cumulative incidence, 5.7%; 95% CI, 4.1% to 7.7%), and 283 patients died (12-month cumulative incidence, 43%; 95% CI, 39% to 46%). The 12-month incidence of recurrent venous thromboembolism was 6.4% in those with subsegmental pulmonary embolism compared with 6.0% in those with more proximal pulmonary embolism (subdistribution hazard ratio, 1.1; 95% CI, 0.37 to 2.9; P = .93). CONCLUSION: In patients with cancer with incidental pulmonary embolism, risk of recurrent venous thromboembolism is significant despite anticoagulant treatment. Patients with subsegmental pulmonary embolism seemed to have a risk of recurrent venous thromboembolism comparable to that of patients with more proximal clots.

Clinical Impact and Course of Anticoagulant-Related Major Bleeding in Cancer Patients.

Cancer patients with venous thromboembolism (VTE) have a two- to six-fold increased risk of anticoagulant-related major bleeding events compared with VTE patients without cancer. It is unknown whether major bleeding events are more severe in cancer patients than in those without cancer. Individual patient data from four randomized phase III trials that compared factor Xa inhibitors and vitamin K antagonists for the treatment of VTE were used to compare the severity of major bleeding events in patients with and without cancer. Using predefined criteria, the severity of the clinical presentation and course of major bleeding events were classified into four categories of increasing severity. A one-stage meta-analysis was used to evaluate the effect of cancer on the severity of the clinical presentation and course by estimating crude odds ratios (ORs) and ORs adjusted for age, sex and anticoagulant type with 95% confidence intervals (CIs). The study group comprised 290 patients with major bleeding, of whom 50 (17%) had cancer. The clinical presentation was judged to be severe (category 3 or 4) in 38% of patients with cancer and 44% of patients without cancer (adjusted OR, 0.90; 95% CI, 0.47-1.72). The clinical course was found to be severe in 20 and 25% of patients with and without cancer, respectively (adjusted OR, 0.75; 95% CI, 0.35-1.61). The present study suggests that the clinical presentation and course of anticoagulant-related major bleeding events are not more severe in cancer patients than in patients without cancer. This may be reassuring for physicians who treat cancer patients with anticoagulant-related bleeding.

Clinical impact of major bleeding in patients with venous thromboembolism treated with factor Xa inhibitors or vitamin K antagonists. An individual patient data meta-analysis.

Factor Xa (fXa)-inhibitors are as effective and safer than vitamin-K-antagonists (VKA) in the treatment of venous thromboembolism (VTE). We previously classified the severity of clinical presentation and course of all major bleeding events from the EINSTEIN, AMPLIFY and HOKUSAI-VTE trials separately. The current aim was to combine these findings in order to increase precision, assess a class effect and analyse presentation and course for different types of bleeding, i. e. intracranial, gastro-intestinal, and other. We classified the clinical presentation and course of all major bleeding events using pre-defined criteria. Both classifications comprised four categories; one being the mildest, and four the most severe. Odds ratios (OR) were calculated for all events classified as category three or four between fXa-inhibitors and VKA recipients. Also, ORs were computed for different types of bleeding. Major bleeding occurred in 111 fXa-inhibitor recipients and in 187 LMWH/VKA recipients. The clinical presentation was classified as category three or four in 35 % and 48 % of the major bleeds in fXa inhibitor and VKA recipients, respectively (OR 0.59, 95 % CI 0.36-0.97). For intracranial, gastro-intestinal and other bleeding a trend towards a less severe presentation was observed for patients treated with fXa inhibitors. Clinical course was classified as severe in 22 % of the fXa inhibitor and 25 % of the VKA associated bleeds (OR 0.83, 95 % CI 0.47-1.46). In conclusion, FXa inhibitor associated major bleeding events had a significantly less severe presentation and a similar course compared to VKA. This finding was consistent for different types of bleeding.

Comparison of risk prediction scores for venous thromboembolism in cancer patients: a prospective cohort study.

In ambulatory patients with solid cancer, routine thromboprophylaxis to prevent venous thromboembolism is not recommended. Several risk prediction scores to identify cancer patients at high risk of venous thromboembolism have been proposed, but their clinical usefulness remains a matter of debate. We evaluated and directly compared the performance of the Khorana, Vienna, PROTECHT, and CONKO scores in a multinational, prospective cohort study. Patients with advanced cancer were eligible if they were due to undergo chemotherapy or had started chemotherapy in the previous three months. The primary outcome was objectively confirmed symptomatic or incidental deep vein thrombosis or pulmonary embolism during a 6-month follow-up period. A total of 876 patients were enrolled, of whom 260 (30%) had not yet received chemotherapy. Fifty-three patients (6.1%) developed venous thromboembolism. The c-statistics of the scores ranged from 0.50 to 0.57. At the conventional positivity threshold of 3 points, the scores classified 13-34% of patients as high-risk; the 6-month incidence of venous thromboembolism in these patients ranged from 6.5% (95%CI: 2.8-12) for the Khorana score to 9.6% (95%CI: 6.6-13) for the PROTECHT score. High-risk patients had a significantly increased risk of venous thromboembolism when using the Vienna (subhazard ratio 1.7; 95%CI: 1.0-3.1) or PROTECHT (subhazard ratio 2.1; 95%CI: 1.2-3.6) scores. In conclusion, the prediction scores performed poorly in predicting venous thromboembolism in cancer patients. The Vienna CATS and PROTECHT scores appear to discriminate better between low- and high-risk patients, but further improvements are needed before they can be considered for introduction into clinical practice.

Abnormal vaginal bleeding in women with venous thromboembolism treated with apixaban or warfarin.

Abnormal vaginal bleeding can complicate direct oral anticoagulant (DOAC) treatment. We aimed to investigate the characteristics of abnormal vaginal bleeding in patients with venous thromboembolism (VTE) receiving apixaban or enoxaparin/warfarin. Data were derived from the AMPLIFY trial. We compared the incidence of abnormal vaginal bleeding between patients in both treatment arms and collected information on clinical presentation, diagnostic procedures, management and outcomes. In the AMPLIFY trial, 1122 women were treated with apixaban and 1106 received enoxaparin/warfarin. A clinically relevant non-major (CRNM) vaginal bleeding occurred in 28 (2.5 %) apixaban and 24 (2.1 %) enoxaparin/warfarin recipients (odds ratio [OR] 1.2, 95 % confidence interval [CI] 0.7-2.0). Of all CRNM bleeds, 28 of 62 (45 %) and 24 of 120 (20 %) were of vaginal origin in the apixaban and enoxaparin/warfarin group, respectively (OR 3.4; 95 % CI 1.8-6.7). Premenopausal vaginal bleeds on apixaban were characterised by more prolonged bleeding (OR 2.3; 95 %CI 0.5-11). In both pre- and postmenopausal vaginal bleeds, diagnostic tests were performed in six (21 %) and in seven (29 %) apixaban and enoxaparin/warfarin treated patients, respectively. Medical treatment was deemed not necessary in 16 (57 %) apixaban and 16 (67 %) enoxaparin/warfarin recipients. The severity of clinical presentation and course of the bleeds was mild in 75 % of the cases in both groups. In conclusion, although the absolute number of vaginal bleeding events is comparable between apixaban and enoxaparin/warfarin recipients, the relative occurrence of vaginal bleeds is higher in apixaban-treated women. The characteristics and severity of bleeding episodes were comparable in both treatment arms.

Clinical impact of major bleeding in patients with venous thromboembolism treated with factor Xa inhibitors or vitamin K antagonists.

Factor Xa (fXa)-inhibitors are as effective and safer than vitamin-K-antagonists (VKA) in the treatment of venous thromboembolism (VTE). We previously classified the severity of clinical presentation and course of all major bleeding events from the EINSTEIN, AMPLIFY and HOKUSAI-VTE trials separately. The current aim was to combine these findings in order to increase precision, assess a class effect and analyse presentation and course for different types of bleeding, i. e. intracranial, gastro-intestinal, and other. We classified the clinical presentation and course of all major bleeding events using pre-defined criteria. Both classifications comprised four categories; one being the mildest, and four the most severe. Odds ratios (OR) were calculated for all events classified as category three or four between fXa-inhibitors and VKA recipients. Also, ORs were computed for different types of bleeding. Major bleeding occurred in 111 fXa-inhibitor recipients and in 187 LMWH/VKA recipients. The clinical presentation was classified as category three or four in 35% and 48% of the major bleeds in fXa inhibitor and VKA recipients, respectively (OR 0.59, 95% CI 0.36-0.97). For intracranial, gastro-intestinal and other bleeding a trend towards a less severe presentation was observed for patients treated with fXa inhibitors. Clinical course was classified as severe in 22% of the fXa inhibitor and 25% of the VKA associated bleeds (OR 0.83, 95% CI 0.47-1.46). In conclusion, FXa inhibitor associated major bleeding events had a significantly less severe presentation and a similar course compared to VKA. This finding was consistent for different types of bleeding.

A clinical decision rule and D-dimer testing to rule out upper extremity deep vein thrombosis in high-risk patients.

INTRODUCTION: In a management study, a diagnostic algorithm consisting of a clinical decision rule, D-dimer, and ultrasonography was shown to safely exclude upper extremity deep vein thrombosis (UEDVT). Efficiency may be lower in high-risk subgroups: those with a central venous catheter or pacemaker, inpatients, cancer, and elderly patients. METHODS: Data of 406 patients with suspected UEDVT enrolled in a prospective management study were used for the present analysis. The aim was to evaluate the efficiency of the algorithm in subgroups, defined as the proportion of patients in whom imaging could be safely withheld based on the combination of a decision rule result indicating "UEDVT unlikely" and a normal D-dimer result. RESULTS: The strategy excluded UEDVT in 87 of 406 patients (21%); ultrasonography was withheld in these patients and none developed UEDVT during 3months of follow-up. In contrast, ultrasonography could be withheld in only 4 of 92 patients with a catheter or pacemaker (4.3%; 95% CI: 1.7% to 11%) and in 4 of 83 inpatients (4.8%; 95% CI: 1.9% to 12%). The efficiency was 11% in patients with cancer and 13% in those older than 75years. CONCLUSION: Although the combination of a decision rule and D-dimer testing is safe in excluding UEDVT in the overall population of patients with suspected UEDVT, its efficiency appears limited in some subgroups, in particular those with a central venous catheter or pacemaker, and inpatients.

Clinical presentation and course of bleeding events in patients with venous thromboembolism, treated with apixaban or enoxaparin and warfarin. Results from the AMPLIFY trial.

Apixaban, a direct acting oral anticoagulant (DOAC), was found to be non-inferior to and safer as enoxaparin followed by warfarin for treatment of venous thromboembolism (VTE) in the AMPLIFY trial. Information is needed on how bleeding events with DOACs present and develop. In this post-hoc analysis, the clinical presentation and course of all major and clinically relevant non major (CRNM) bleeding events in the AMPLIFY trial were blindly classified by three investigators, using pre-designed classification schemes containing four categories. Odds ratios (OR) for classifying as category three or four (representing a more severe clinical presentation and course) were calculated between apixaban and enoxaparin/warfarin. In total, 63 major and 311 CRNM bleeding events were classified. Of the major bleeds, a more severe clinical presentation occurred in 28.5 % of apixaban versus 44.9 % of enoxaparin/warfarin related recipients (OR 0.49, 95 % confidence interval [CI] 0.14-1.78). A severe clinical course was observed in 14.3 % and in 12.2 %, respectively (OR 1.19, 95 %CI 0.21-6.69). Of the CRNM bleeding events, a more severe clinical presentation and extent of clinical care was found in 25 % of apixaban recipients compared to 22.7 % in the enoxaparin/warfarin group (OR 1.13, 95 %CI 0.65-1.97). The clinical presentation and course of major and CRNM bleeds were similar in apixaban and enoxaparin/warfarin treated patients. This finding should reassure physicians and patients that even in the absence of a specific reversal agent, apixaban is a convenient and safe choice for VTE.

Low-molecular-weight heparin to prevent recurrent venous thromboembolism in pregnancy: Rationale and design of the Highlow study, a randomised trial of two doses.

BACKGROUND: Women with a history of venous thromboembolism (VTE) have a 2% to 10% absolute risk of VTE recurrence during subsequent pregnancies. Therefore, current guidelines recommend that all pregnant women with a history of VTE receive pharmacologic thromboprophylaxis. The optimal dose of low-molecular-weight heparin (LMWH) for thromboprophylaxis is unknown. In the Highlow study (NCT 01828697; www.highlowstudy.org), we compare a fixed low dose of LMWH with an intermediate dose of LMWH for the prevention of pregnancy-associated recurrent VTE. We present the rationale and design features of this study. METHODS: The Highlow study is an investigator-initiated, multicentre, international, open-label, randomised trial. Pregnant women with a history of VTE and an indication for ante- and postpartum pharmacologic thromboprophylaxis are included before 14weeks of gestation. The primary efficacy outcome is symptomatic recurrent VTE during pregnancy and 6weeks postpartum. The primary safety outcomes are clinically relevant bleeding, blood transfusions before 6weeks postpartum and mortality. Patients are closely monitored to detect cutaneous reactions to LMWH and are followed for 3months after delivery. A central independent adjudication committee adjudicates all suspected outcome events. CONCLUSION: The Highlow study is the first large randomised controlled trial in pregnancy that will provide high-quality evidence on the optimal dose of LWMH thromboprophylaxis for the prevention of recurrent VTE in pregnant women with a history of VTE.

Use of heparins in patients with cancer: individual participant data meta-analysis of randomised trials study protocol.

INTRODUCTION: Parenteral anticoagulants may improve outcomes in patients with cancer by reducing risk of venous thromboembolic disease and through a direct antitumour effect. Study-level systematic reviews indicate a reduction in venous thromboembolism and provide moderate confidence that a small survival benefit exists. It remains unclear if any patient subgroups experience potential benefits. METHODS AND ANALYSIS: First, we will perform a comprehensive systematic search of MEDLINE, EMBASE and The Cochrane Library, hand search scientific conference abstracts and check clinical trials registries for randomised control trials of participants with solid cancers who are administered parenteral anticoagulants. We anticipate identifying at least 15 trials, exceeding 9000 participants. Second, we will perform an individual participant data meta-analysis to explore the magnitude of survival benefit and address whether subgroups of patients are more likely to benefit from parenteral anticoagulants. All analyses will follow the intention-to-treat principle. For our primary outcome, mortality, we will use multivariable hierarchical models with patient-level variables as fixed effects and a categorical trial variable as a random effect. We will adjust analysis for important prognostic characteristics. To investigate whether intervention effects vary by predefined subgroups of patients, we will test interaction terms in the statistical model. Furthermore, we will develop a risk-prediction model for venous thromboembolism, with a focus on control patients of randomised trials. ETHICS AND DISSEMINATION: Aside from maintaining participant anonymity, there are no major ethical concerns. This will be the first individual participant data meta-analysis addressing heparin use among patients with cancer and will directly influence recommendations in clinical practice guidelines. Major cancer guideline development organisations will use eventual results to inform their guideline recommendations. Several knowledge users will disseminate results through presentations at clinical rounds as well as national and international conferences. We will prepare an evidence brief and facilitate dialogue to engage policymakers and stakeholders in acting on findings. TRIAL REGISTRATION NUMBER: PROSPERO CRD42013003526.

Clinical course of upper extremity deep vein thrombosis in patients with or without cancer: a systematic review.

BACKGROUND: The incidence of upper extremity deep vein thrombosis (UEDVT) is increasing. Information on the clinical course of UEDVT is scarce, especially in cancer patients. AIM: To summarize the clinical evidence regarding long-term clinical outcomes of UEDVT, in terms of recurrent venous thromboembolism (VTE), mortality, and anticoagulant-related bleeding, in patients with or without concomitant cancer. METHODS: A systematic search of the literature was conducted in MEDLINE, EMBASE and BIOSIS Previews. Incidence rates for all outcome variables were calculated. RESULTS: In total, 45 studies comprising 4580 patients were included. No randomized controlled trials were identified. In most studies, patients were treated solely with anticoagulants. Among the prospective studies, the incidences of recurrent VTE and bleeding complications averaged 5.1% and 3.1% respectively, during 3 to 59months of follow-up. In the retrospective studies these figures were 9.8% and 6.7% respectively. Among the prospective studies, the mortality rate was 24% after one year. In the retrospective studies this rate was 35%. Cancer patients were found to have a 2- to 3-fold higher risk of recurrent VTE, an 8-fold increased risk of mortality, and a 4-fold increased risk of bleeding during anticoagulant therapy, compared to non-cancer patients. CONCLUSIONS: Studies were very heterogeneous in terms of study design, study populations and treatment approaches. Follow-up durations varied greatly, hampering combined analyses of average incidence rates. There is a need for large prospective studies to provide information on the best management of this disease, especially in high risk groups such as those with cancer.

Clinical impact and course of major bleeding with edoxaban versus vitamin K antagonists.

Edoxaban is a once-daily direct oral anticoagulant (DOAC). The Hokusai-VTE study revealed that, after initial treatment with heparin, edoxaban was non-inferior to and safer than vitamin K antagonists (VKA) in the prevention of recurrent deep-vein thrombosis and pulmonary embolism. This is the first report on the clinical relevance and management of bleeding events with edoxaban. All major bleeding events were classified blindly by three study-independent adjudicators. Pre-defined criteria were used to classify severity of clinical presentation and, separately, the clinical course and outcome into four categories. Major bleeding occurred in 56 patients treated with edoxaban and 65 patients treated with VKA. The severest categories (3 or 4) of the clinical presentation were assigned to 46 % of the major bleeding episodes in edoxaban recipients versus 58 % of the major bleeds in VKA recipients (odds ratio [OR] 0.62, 95 % confidence interval [CI] 0.30-1.27, p = 0.19). Clinical course was classified as severe (category 3 or 4) in 23 % of the edoxaban and 29 % of the VKA associated bleeds (OR 0.73, 95 % CI 0.32-1.66, p = 0.46). In conclusion, edoxaban associated major bleeding events have a comparable clinical presentation and course to major bleeds with VKA in patients treated for venous thromboembolism in the Hokusai-VTE study. These results may assure physicians that it is safe to prescribe this medication. If a major bleeding during edoxaban treatment occurs, its clinical presentation and clinical course are not worse than in VKA-treated patients.

Prevention and Treatment of Venous Thromboembolism in Patients with Cancer: Focus on Drug Therapy.

Venous thromboembolism (VTE) is a frequent complication in patients with cancer and is associated with significant morbidity and mortality. The use of anticoagulants for the prevention and treatment of VTE in this population is challenging given the high risk of both recurrent VTE and bleeding complications. Thromboprophylaxis with subcutaneous low-molecular-weight heparin (LMWH) is recommended in cancer patients hospitalized for an acute medical illness and in those undergoing major surgery. In ambulatory cancer patients with or without central venous catheters, routine thromboprophylaxis is not recommended because of the relatively low benefit-to-risk ratio. To identify cancer outpatients at very high risk of VTE who may benefit from thromboprophylaxis, VTE risk stratification tools based on tumour type, clinical parameters, or coagulation biomarkers have been proposed, but their clinical utility needs validation. The mainstay of treatment for cancer-associated VTE is LMWH for at least 6 months or longer in case of active disease. The same initial and long-term treatment for incidental VTE as for symptomatic VTE can be suggested while awaiting additional studies in this area.

Clinical Significance of Tissue Factor-Exposing Microparticles in Arterial and Venous Thrombosis.

Microparticles (MP) are small extracellular vesicles (30-1,000 nm) that are released from activated cells or platelets. Exposure of negatively charged phospholipids and tissue factor (TF) renders MP procoagulant. Normal plasma levels of intravascular TF-exposing MP (TFMP) are low, but their number may rise in pathological conditions, including cancer and infectious disease. Emerging evidence indicates an important role for these circulating TFMP in the pathogenesis of thrombotic complications such as venous thromboembolism and disseminated intravascular coagulation, whereas their contribution to arterial thrombosis is less studied. Despite serious limitations of the currently available assays for measuring TFMP levels or the procoagulant activity associated with TFMP with respect to sensitivity and specificity, the scientific interest in TFMP is rapidly growing because their application as prognostic biomarkers for thrombotic complications is promising. Future advances in detection methods will likely provide more insight into TFMP and eventually improve their clinical utility.

Edoxaban for treatment of venous thromboembolism in patients with cancer. Rationale and design of the Hokusai VTE-cancer study.

Direct oral anticoagulants may be effective and safe for treatment of venous thromboembolism (VTE) in cancer patients, but they have not been compared with low-molecular-weight heparin (LMWH), the current recommended treatment for these patients. The Hokusai VTE-cancer study is a randomised, open-label, clinical trial to evaluate whether edoxaban, an oral factor Xa inhibitor, is non-inferior to LMWH for treatment of VTE in patients with cancer. We present the rationale and some design features of the study. One such feature is the composite primary outcome of recurrent VTE and major bleeding during a 12-month study period. These two complications occur frequently in cancer patients receiving anticoagulant treatment and have a significant impact. The evaluation beyond six months will fill the current gap in the evidence base for the long-term treatment of these patients. Based on the observation that the risk of recurrent VTE in patients with active cancer is similar to that in those with a history of cancer, the Hokusai VTE-cancer study will enrol patients if whose cancer was diagnosed within the past two years. In addition, patients with incidental VTE are eligible because their risk of recurrent VTE is similar to that in patients with symptomatic disease. The unique design features of the Hokusai VTE-cancer study should lead to enrolment of a broad spectrum of cancer patients with VTE who could benefit from oral anticoagulant treatment.

Safety of anticoagulant treatment in cancer patients.

INTRODUCTION: Patients with cancer are at increased risk of (recurrent) venous thromboembolism. They are also at increased risk of bleeding. This makes treatment of venous thromboembolisms (VTE) in cancer patients challenging. AREAS COVERED: In this review, we will focus on the safety of anticoagulant treatment of VTE in cancer patients. We will discuss the absolute and relative bleeding risks associated with the various types of anticoagulants, specifically focusing on low-molecular-weight heparins (LMWH), vitamin K antagonist (VKA) and the new oral anticoagulants (NOACs). EXPERT OPINION: Monotherapy with LMWH is recommended for treatment of acute VTE in cancer patients. The bleeding risk associated with LMWH is comparable to VKAs, but LMWH are more effective in preventing recurrent VTE. More evidence on the efficacy and safety of NOACs in cancer patients is needed.

Cancer-associated unsuspected pulmonary embolism.

Clinically unsuspected pulmonary embolism (UPE) is frequently diagnosed in cancer patients undergoing routine computed tomography scans for staging purposes or treatment response evaluation. The reported incidence of UPE ranges from 1% to 5% which probably represents an underestimation. A significant proportion of cancer patients with UPE actually do have pulmonary embolism (PE) related symptoms. However, these can erroneously be attributed to the cancer itself or to cancer therapy leading to a delayed or missed diagnosis. The incidence of UPE is likely to increase further with the improvements of imaging techniques. Radiologic features of UPE appear similar to symptomatic PE with nearly half of the UPE located in central pulmonary arteries and one third involving both lungs. UPE in cancer patients is not a benign condition with rates of recurrent venous thromboembolic events, bleeding and a mortality rate comparable to cancer patients with symptomatic PE. Current guidelines suggest that UPE should receive similar initial and long-term anticoagulant treatment as for symptomatic PE. However, direct evidence regarding the treatment of UPE is scarce and treatment indications are largely derived from studies performed in cancer patients with symptomatic venous thromboembolism. Selected subgroups of cancer patients with UPE such as those with sub-segmental UPE may be treated conservatively by withholding anticoagulation and avoiding the associated bleeding risk, although this requires further evaluation.

Sex, thrombosis and inherited thrombophilia.

The incidence of venous thromboembolism (VTE) is two-fold higher in women than in men during reproductive age, which is likely explained by the use of hormonal contraceptives and by pregnancy in this phase of life. After adjustment for these factors, men have a two-fold higher risk of developing a first VTE compared with women, which is in line with earlier observations that men have a two-fold higher risk of recurrent VTE. These findings indicate that the intrinsic risk of VTE is higher in men than in women. Hormonal contraceptives increase the risk of VTE and the risk varies per type, dose, and administration route. In women with a high baseline risk of VTE, avoidance of some hormonal contraceptives should be considered, as well as thrombosis prophylaxis during pregnancy. Presence of hereditary thrombophilia increases the risk of a first VTE episode. This review focuses on the differences in risk of VTE between men and women, hormonal risk factors for women, and how these interact with common types of hereditary thrombophilia.