Challenging anticoagulation cases: Acute extensive portal vein thrombosis in a patient without cirrhosis - Evidence-based management of a rare clinical entity.

Acute non-cirrhotic and non-malignant portal vein thrombosis (aPVT) is a rare and heterogenous condition. Current guidelines recommend early initiation of therapeutic anticoagulation to prevent extension of thrombosis, and favor recanalization. Although not formally defined, a poor outcome in the acute setting would include thrombosis extension with progression to intestinal infarction. Patients are also at risk of negative long-term outcomes related to complications of portal hypertension, such as variceal bleeding, ascites, and portal cholangiopathy. Identifying patients at risk of these events despite early initiation of anticoagulation remains challenging. Trials comparing treatment strategies in those failing standard therapy with meaningful radiological and clinical endpoints, whether in the short or long term, are desperately needed. The objective of this review will be to discuss a real-life clinical case and propose a treatment approach for aPVT based on the available evidence. We will mainly focus on management strategies including anticoagulation, prognostic factors, and options beyond anticoagulation, such as thrombolysis, thrombectomy, and transjugular intrahepatic portosystemic shunts. This review will not cover tumor portal vein thrombosis or thrombosis associated with cirrhosis.

Postoperative low molecular weight heparin bridging treatment for patients at high risk of arterial thromboembolism (PERIOP2): double blind randomised controlled trial.

OBJECTIVE: To determine the efficacy and safety of dalteparin postoperative bridging treatment versus placebo for patients with atrial fibrillation or mechanical heart valves when warfarin is temporarily interrupted for a planned procedure. DESIGN: Prospective, double blind, randomised controlled trial. SETTING: 10 thrombosis research sites in Canada and India between February 2007 and March 2016. PARTICIPANTS: 1471 patients aged 18 years or older with atrial fibrillation or mechanical heart valves who required temporary interruption of warfarin for a procedure. INTERVENTION: Random assignment to dalteparin (n=821; one patient withdrew consent immediately after randomisation) or placebo (n=650) after the procedure. MAIN OUTCOME MEASURES: Major thromboembolism (stroke, transient ischaemic attack, proximal deep vein thrombosis, pulmonary embolism, myocardial infarction, peripheral embolism, or vascular death) and major bleeding according to the International Society on Thrombosis and Haemostasis criteria within 90 days of the procedure. RESULTS: The rate of major thromboembolism within 90 days was 1.2% (eight events in 650 patients) for placebo and 1.0% (eight events in 820 patients) for dalteparin (P=0.64, risk difference -0.3%, 95% confidence interval -1.3 to 0.8). The rate of major bleeding was 2.0% (13 events in 650 patients) for placebo and 1.3% (11 events in 820 patients) for dalteparin (P=0.32, risk difference -0.7, 95% confidence interval -2.0 to 0.7). The results were consistent for the atrial fibrillation and mechanical heart valves groups. CONCLUSIONS: In patients with atrial fibrillation or mechanical heart valves who had warfarin interrupted for a procedure, no significant benefit was found for postoperative dalteparin bridging to prevent major thromboembolism. TRIAL REGISTRATION: Clinicaltrials.gov NCT00432796.

Venous thromboembolism.

Venous thromboembolism, comprising both deep vein thrombosis and pulmonary embolism, is a chronic illness that affects nearly 10 million people every year worldwide. Strong provoking risk factors for venous thromboembolism include major surgery and active cancer, but most events are unprovoked. Diagnosis requires a sequential work-up that combines assessment of clinical pretest probability for venous thromboembolism using a clinical score (eg, Wells score), D-dimer testing, and imaging. Venous thromboembolism can be considered excluded in patients with both a non-high clinical pretest probability and normal D-dimer concentrations. When required, ultrasonography should be done for a suspected deep vein thrombosis and CT or ventilation-perfusion scintigraphy for a suspected pulmonary embolism. Direct oral anticoagulants (DOACs) are the first-line treatment for almost all patients with venous thromboembolism (including those with cancer). After completing 3-6 months of initial treatment, anticoagulation can be discontinued in patients with venous thromboembolism provoked by a major transient risk factor. Patients whose long-term risk of recurrent venous thromboembolism outweighs the long-term risk of major bleeding, such as those with active cancer or men with unprovoked venous thromboembolism, should receive indefinite anticoagulant treatment. Pharmacological venous thromboembolism prophylaxis is generally warranted in patients undergoing major orthopaedic or cancer surgery. Ongoing research is focused on improving diagnostic strategies for suspected deep vein thrombosis, comparing different DOACs, developing safer anticoagulants, and further individualising approaches for the prevention and management of venous thromboembolism.

Long-term risk of recurrent venous thromboembolism after a first contraceptive-related event: Data from REVERSE cohort study.

INTRODUCTION: The risk of recurrent venous thromboembolism (VTE) after combined oral contraceptive (COC) use is variably reported. We assessed the long-term risk of recurrent VTE in women on COC at the time of a first VTE, in comparison to women without COC use. Our secondary aim assessed the impact of COC use on the recurrent VTE risk in high-risk and low-risk hyperpigmentation, edema, or redness in either leg; D-dimer level ≥250 µg/L; obesity with body mass index ≥30; or older age, ≥65 years (HERDOO2) subgroups. METHODS: The REVERSE cohort study derived the HERDOO2 clinical decision rule to predict recurrent VTE in patients who discontinued anticoagulation after 5-7 months for a first unprovoked VTE. Incidence rates of recurrent VTE among women with and without COC exposure were calculated as the number of recurrent VTE over the number of person-years of follow-up, and Cox proportional hazards model was used to compare risks between groups. RESULTS: The risk of recurrent VTE among COC users was 1.1% (95% confidence interval [CI] 0.3-2.9) per patient-year as compared with 3.2% per patient-year (95% CI 2.4-4.3) among nonusers (hazard ratio 0.37; 95% CI 0.1-1.0). Women who were COC users and high risk by HERDOO2 score had a recurrence rate of 3.5% (95% CI 0.4-12.5) compared with 6.1% (95% CI 4.3-8.5) among women who were non-COC users and at high risk by HERDOO2 score (HR 0.6, 95% CI 0.1-2.5). CONCLUSIONS: Women who were COC users at the time of an otherwise unprovoked VTE event had a lower VTE recurrence rate during long-term follow-up, compared with nonusers. The use of HERDOO2 rule may help identify higher risk women with COC use.

The determinants of maternal homocysteine in pregnancy: findings from the Ottawa and Kingston Birth Cohort.

OBJECTIVE: Observational studies have linked elevated homocysteine to vascular conditions. Folate intake has been associated with lower homocysteine concentration, although randomised controlled trials of folic acid supplementation to decrease the incidence of vascular conditions have been inconclusive. We investigated determinants of maternal homocysteine during pregnancy, particularly in a folic acid-fortified population. DESIGN: Data were from the Ottawa and Kingston Birth Cohort of 8085 participants. We used multivariable regression analyses to identify factors associated with maternal homocysteine, adjusted for gestational age at bloodwork. Continuous factors were modelled using restricted cubic splines. A subgroup analysis examined the modifying effect of MTHFR 677C>T genotype on folate, in determining homocysteine concentration. SETTING: Participants were recruited in Ottawa and Kingston, Canada, from 2002 to 2009. PARTICIPANTS: Women were recruited when presenting for prenatal care in the early second trimester. RESULTS: In 7587 participants, factors significantly associated with higher homocysteine concentration were nulliparous, smoking and chronic hypertension, while factors significantly associated with lower homocysteine concentration were non-Caucasian race, history of a placenta-mediated complication and folic acid supplementation. Maternal age and BMI demonstrated U-shaped associations. Folic acid supplementation of >1 mg/d during pregnancy did not substantially increase folate concentration. In the subgroup analysis, MTHFR 677C>T modified the effect of folate status on homocysteine concentration. CONCLUSIONS: We identified determinants of maternal homocysteine relevant to the lowering of homocysteine in the post-folic acid fortification era, characterised by folate-replete populations. A focus on periconceptional folic acid supplementation and improving health status may form an effective approach to lower homocysteine.

Management of suspected and confirmed recurrent venous thrombosis while on anticoagulant therapy. What next?

Suspected recurrent venous thromboembolism (VTE) is a common and vexing clinical problem. Confounding the diagnosis of recurrent VTE is a high frequency of residual VTE from prior VTE. The diagnosis of recurrent VTE must be established by comparing current imaging with past imaging to distinguish acute from chronic thrombosis. Next, we must ascertain if non-compliance was the cause of "apparent therapeutic failure" and if non-compliance is at play then re-initiate anticoagulant therapy. Therapeutic failure is relatively uncommon. As such, we must consider underlying causes of therapeutic failures including malignancy and potent thrombophilias. Finally, short term anticoagulant management of therapeutic failures is controversial, and requires further research, but the best current evidence supports a course of full-dose low-molecular-weight heparin (LMWH) (and dose escalated LMWH if failure occurs while on full-dose LMWH).

Apixaban to Prevent Venous Thromboembolism in Patients with Cancer.

BACKGROUND: Patients with active cancer have an increased risk of venous thromboembolism, which results in substantial morbidity, mortality, and health care expenditures. The Khorana score (range, 0 to 6, with higher scores indicating a higher risk of venous thromboembolism) has been validated to identify patients with cancer at elevated risk for this complication and may help select those who could benefit from thromboprophylaxis. METHODS: We conducted a randomized, placebo-controlled, double-blind clinical trial assessing the efficacy and safety of apixaban (2.5 mg twice daily) for thromboprophylaxis in ambulatory patients with cancer who were at intermediate-to-high risk for venous thromboembolism (Khorana score, ≥2) and were initiating chemotherapy. The primary efficacy outcome was objectively documented venous thromboembolism over a follow-up period of 180 days. The main safety outcome was a major bleeding episode. RESULTS: Of the 574 patients who underwent randomization, 563 were included in the modified intention-to-treat analysis. Venous thromboembolism occurred in 12 of 288 patients (4.2%) in the apixaban group and in 28 of 275 patients (10.2%) in the placebo group (hazard ratio, 0.41; 95% confidence interval [CI], 0.26 to 0.65; P<0.001). In the modified intention-to-treat analysis, major bleeding occurred in 10 patients (3.5%) in the apixaban group and in 5 patients (1.8%) in the placebo group (hazard ratio, 2.00; 95% CI, 1.01 to 3.95; P = 0.046). During the treatment period, major bleeding occurred in 6 patients (2.1%) in the apixaban group and in 3 patients (1.1%) in the placebo group (hazard ratio, 1.89; 95% CI, 0.39 to 9.24). CONCLUSIONS: Apixaban therapy resulted in a significantly lower rate of venous thromboembolism than did placebo among intermediate-to-high-risk ambulatory patients with cancer who were starting chemotherapy. The rate of major bleeding episodes was higher with apixaban than with placebo. (Funded by the Canadian Institutes of Health Research and Bristol-Myers Squibb-Pfizer Alliance; AVERT ClinicalTrials.gov number, NCT02048865.).

Who should get long-term anticoagulant therapy for venous thromboembolism and with what?

After an initial 3 to 6 months of anticoagulation for venous thromboembolism (VTE), clinicians and patients face an important question: "Do we stop anticoagulants or continue them indefinitely?" The decision is easy in some scenarios (eg, stop in VTE provoked by major surgery). In most scenarios, which are faced on a day-to-day basis in routine practice, it is a challenging decision because of uncertainty in estimates in the long-term risks (principally major bleeding) and benefits (reducing recurrent VTE) and the tight trade-offs between them. Once the decision is made to continue, the next question to tackle is "Which anticoagulant?" Here again, it is a difficult decision because of the uncertainty with regard to estimates of efficacy and the safety of anticoagulant options and the tight trade-offs between choices. We conclude with the approach that we take in our clinical practice.

Who should get long-term anticoagulant therapy for venous thromboembolism and with what?

After an initial 3 to 6 months of anticoagulation for venous thromboembolism (VTE), clinicians and patients face an important question: "Do we stop anticoagulants or continue them indefinitely?" The decision is easy in some scenarios (eg, stop in VTE provoked by major surgery). In most scenarios, which are faced on a day-to-day basis in routine practice, it is a challenging decision because of uncertainty in estimates in the long-term risks (principally major bleeding) and benefits (reducing recurrent VTE) and the tight trade-offs between them. Once the decision is made to continue, the next question to tackle is "Which anticoagulant?" Here again, it is a difficult decision because of the uncertainty with regard to estimates of efficacy and the safety of anticoagulant options and the tight trade-offs between choices. We conclude with the approach that we take in our clinical practice.

Predicting the risk of recurrent venous thromboembolism in patients with cancer: A prospective cohort study.

BACKGROUND: The risk of recurrent venous thromboembolism (VTE) in cancer patients despite anticoagulant therapy is high. Clinical factors and pro-coagulant markers may identify high-risk patients and guide decisions about intensifying anticoagulation therapy. AIMS: To evaluate whether serial measurements of pro-coagulant markers can identify patients at high risk of recurrent VTE. METHODS: In this multicenter, prospective cohort study, patients with active cancer and acute deep vein thrombosis or pulmonary embolism were enrolled. Patients received standard low-molecular-weight heparin therapy and were followed for 6 months. D-dimer and soluble P-selectin levels were measured at baseline and 1, 4, 5, 12, and 24 weeks post treatment initiation. The association between recurrent VTE and a previously developed risk score, baseline values of the biomarkers, and individual relative changes from baseline were assessed. RESULTS: We enrolled 117 cancer patients (22% lung, 21% colorectal, 9% breast) with a mean age of 63 years; 62% had metastatic cancer. Eleven patients (9.4%) developed recurrent VTE, including two cases of fatal pulmonary embolism. VTE recurrence rates were 7.8% (95% CI, 3.1-18) in patients with a risk score of ≤0 points compared to 11% (95% CI, 5.2-20) for those with a score of ≥1 point (hazard ratio 1.3; 95% CI, 0.39-4.5). Baseline P-selectin levels but not D-dimer levels were significantly associated with a high risk of recurrence; the risk was four-fold higher in patients with elevated P-selectin levels than in those with normal levels (hazard ratio 4.0; 95% CI, 1.1-14). Changes in biomarker levels during treatment were not associated with recurrent VTE. CONCLUSION: Baseline P-selectin but not D-dimer levels predict recurrent VTE and may be a valuable addition to clinical prediction rules to select patients for more intensive therapy or closer observation.

The importance of post thrombotic syndrome as an outcome after deep venous thrombosis: A survey of Canadian thrombosis clinicians.

OBJECTIVES: The development of post thrombotic syndrome (PTS) is a major source of morbidity and reduced quality of life. We sought to determine the value assigned by clinicians to post thrombotic syndrome and whether clinicians believe that any post thrombotic syndrome or severe post thrombotic syndrome are important outcomes to assess after deep vein thrombosis (DVT) as compared to other outcomes. DESIGN: The design of the study was a self-responded electronic survey. Questions for the online survey were designed by two authors (R.I. and E.G.). METHODS: The survey was distributed to 233 members of Thrombosis Canada and the Canadian Society for Vascular Surgery between August 2014 and October 2014. RESULTS: There were 84 responses to the survey with complete responses were obtained from 71 respondents for a response rate of 36%. PTS was ranked as a significantly less important outcome after DVT than recurrent DVT, pulmonary embolism during treatment, major bleeding, death, quality of life, venous ulceration and severe post thrombotic syndrome (all comparisons p<0.05 by two sample t-test). CONCLUSIONS: Our survey determined that "any post thrombotic syndrome" is perceived by physicians as less important than other DVT outcomes. Thus, "Severe PTS" and not "Any PTS" should be included as an outcome measure in studies investigating acute DVT.

Pulmonary Complications of Pregnancy: Venous Thromboembolism.

Unique considerations are needed when diagnosing and treating venous thromboembolism (VTE) in women who are pregnant or postpartum. What are the risks to the fetus, such as drug exposure or the risk of radiation with diagnostic imaging? How does the physiology of pregnancy affect imaging techniques and anticoagulation management? How should anticoagulation be managed around labor and delivery? These questions highlight some of the important considerations needed when managing a pregnant patient with suspected or confirmed VTE. This review outlines what is known about the epidemiology, pathophysiology, clinical risk factors, diagnosis, and therapeutic management of VTE in pregnancy. We also review our preferred diagnostic and treatment algorithm for a pregnant patient with suspected or confirmed VTE.

Risk of venous thromboembolism in pregnant women with essential thrombocythemia: a systematic review and meta-analysis.

We performed a meta-analysis to evaluate the risk of venous thromboembolism (VTE) in pregnant women with essential thrombocythemia. Twenty-one trials and 756 pregnancies met inclusion criteria. The absolute VTE risk in the antepartum period is not above a threshold where low-molecular-weight heparin (LMWH) prophylaxis is clearly indicated or below a threshold where LMWH should be withheld (2.5%; 95% CI, 1.3-4.3). Postpartum, the absolute VTE risk is above a threshold where postpartum LMWH prophylaxis should be considered (4.4%; 95% CI, 1.2-9.5).

Functional and Exercise Limitations After a First Episode of Pulmonary Embolism: Results of the ELOPE Prospective Cohort Study.

BACKGROUND: We aimed to determine the frequency and predictors of exercise limitation after pulmonary embolism (PE) and to assess its association with health-related quality of life (HRQoL) and dyspnea. METHODS: One hundred patients with acute PE were recruited at five Canadian hospitals from 2010 to 2013. Cardiopulmonary exercise testing (CPET) was performed at 1 and 12 months. Quality of life (QoL), dyspnea, 6-min walk distance (6MWD), residual clot burden (perfusion scan, CT pulmonary angiography), cardiac function (echocardiography), and pulmonary function tests (PFTs) were measured during follow-up. The prespecified primary outcome was percent predicted peak oxygen uptake (Vo2 peak) < 80% at 1-year CPET. RESULTS: At 1 year, 40 of 86 patients (46.5%) had percent predicted Vo2 peak < 80% on CPET, which was associated with significantly worse generic health-related QoL (HRQoL), PE-specific HRQoL and dyspnea scores, and significantly reduced 6MWD at 1 year. Predictors of the primary outcome included male sex (relative risk [RR], 3.2; 95% CI, 1.3-8.1), age (RR, 0.98; 95% CI, 0.96-0.99 per 1-year age increase), BMI (RR 1.1; 95% CI, 1.01-1.2 per 1 kg/m2 BMI increase), and smoking history (RR, 1.8; 95% CI, 1.1-2.9), as well as percent predicted Vo2 peak < 80% on CPET at 1 month (RR, 3.8; 95% CI,1.9-7.2), and 6MWD at 1 month (RR, 0.82; 95% CI, 0.7-0.9 per 30-m increased walking distance). Baseline or residual clot burden was not associated with the primary outcome. Mean PFT and echocardiographic results (pulmonary artery pressure, right and left ventricular systolic function) at 1 year were similarly within normal limits in both patients with exercise limitations and those without such limitations. CONCLUSIONS: Almost half of patients with PE have exercise limitation at 1 year that adversely influences HRQoL, dyspnea, and walking distance. CPET or 6MWD testing at 1 month may help to identify patients with a higher risk of exercise limitation at 1 year after PE. Based on our results, we believe that the deconditioning that occurs after acute PE could underlie this exercise limitation, but we cannot exclude the fact that this may have been present before PE. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01174628; URL: www.clinicaltrials.gov.

A multicenter prospective study of risk factors and treatment of unusual site thrombosis.

Unusual site deep vein thrombosis (USDVT) is an uncommon form of venous thromboembolism (VTE) with heterogeneity in pathophysiology and clinical features. While the need for anticoagulation treatment is generally accepted, there is little data on optimal USDVT treatment. The TRUST study aimed to characterize the epidemiology, treatment and outcomes of USDVT. From 2008 to 2012, 152 patients were prospectively enrolled at 4 Canadian centers. After baseline, patients were followed at 6, 12 and 24months. There were 97 (64%) cases of splanchnic, 33 (22%) cerebral, 14 (9%) jugular, 6 (4%) ovarian and 2 (1%) renal vein thrombosis. Mean age was 52.9years and 113 (74%) cases were symptomatic. Of 72 (47%) patients tested as part of clinical care, 22 (31%) were diagnosed with new thrombophilia. Of 138 patients evaluated in follow-up, 66 (48%) completed at least 6months of anticoagulation. Estrogen exposure or inflammatory conditions preceding USDVT were commonly associated with treatment discontinuation before 6months, while previous VTE was associated with continuing anticoagulation beyond 6months. During follow-up, there were 22 (16%) deaths (20 from cancer), 4 (3%) cases of recurrent VTE and no fatal bleeding events. Despite half of USDVT patients receiving <6months of anticoagulation, the rate of VTE recurrence was low and anticoagulant treatment appears safe. Thrombophilia testing was common and thrombophilia prevalence was high. Further research is needed to determine the optimal investigation and management of USDVT.