Is stand-alone D-dimer testing safe to rule out acute pulmonary embolism?

Essentials A stand-alone D-dimer below 750 μg/L has been proposed to rule out acute pulmonary embolism (PE). This was a post-hoc analysis on data from 6 studies comprising 7268 patients with suspected PE. The negative predictive value of a D-dimer <750 μg/L ranged from 79% to 96% in various subgroups. Stand-alone D-dimer testing seems to be unsafe to rule out PE in all patients.

SUMMARY

Background Recently, stand-alone D-dimer testing at a positivity threshold of 750 μg L-1 has been proposed as a safe and efficient approach to rule out acute pulmonary embolism (PE), without additional imaging, but this approach needs validation. Objectives To evaluate stand-alone D-dimer testing at a positivity threshold of 750 μg L-1 to rule out PE. Methods Individual data from 7268 patients with suspected PE previously enrolled in six prospective management studies were used. Patients were assessed by the Wells rule followed by quantitative D-dimer testing in those with a 'PE unlikely' score. Patients were classified post hoc as having a negative (< 750 μg L-1 ) or positive (≥ 750 μg L-1 ) D-dimer. Using a one-stage meta-analytic approach, the negative predictive value (NPV) of stand-alone D-dimer testing was evaluated overall and in different risk subgroups. Results The pooled incidence of PE was 23% (range, 13-42%). Overall, 44% of patients had a D-dimer < 750 μg L-1 , of whom 2.8% were diagnosed with PE at baseline or during 3-month follow-up (NPV, 97.2%; 95% confidence interval [CI], 94.9-98.5). The NPV was highest in patients with a low probability of PE according to the Wells rule (99.2%; 95% CI, 98.6-99.5%) and lowest in those with a high probability of PE (79.3%; 95% CI, 53.0-92.8%). The NPVs in patients with active cancer, patients with previous venous thromboembolism and inpatients were 96.2% (95% CI, 85.6-99.1%), 94.7% (95% CI, 88.6-97.6%) and 92.7% (95% CI, 79.3-97.7%), respectively. Conclusions Our findings suggest that stand-alone D-dimer testing at a positivity threshold of 750 μg L-1 is not safe to rule out acute PE.

[Pulmonary embolism response teams: what is the added value for patients with acute pulmonary embolism?]

Adequate triaging of patients presenting with acute pulmonary embolism (PE) is essential for appropriate treatment, especially for patients with severe PE. Optimal treatment for this latter group of patients includes pharmaco-mechanical reperfusion treatment for the minority of patients who present with haemodynamic instability, and standard anticoagulation and close monitoring on the ward for the intermediate-high risk patient. In the USA, pulmonary embolism response teams (PERT) have been introduced to coordinate triaging of these patients. We discuss the potential role of PERT teams in Dutch hospitals. The main advantage of PERT could be a uniform management strategy that is supported by a multidisciplinary team including all key specialists in the treatment of severe PE.

[Continued anticoagulation for unprovoked venous thromboembolism: guidance through the maze of recent studies]

Recent American, European and Dutch guidelines recommend indefinite anticoagulation after a diagnosis of unprovoked venous thromboembolism in the absence of a high bleeding risk. The recommended approach would be to only stop anticoagulant therapy after three months in patients with one or more untreatable risk factors for bleeding such as prior major bleeding, uncorrectable hypertension or deep thrombocytopenia. Vitamin K-antagonists and direct oral anticoagulants (DOACs) were found to protect against recurrent venous thromboembolism at cost of major bleedings, although at a lower frequency than the number of prevented thrombotic events. Due to the lower risk of major bleeding than associated with vitamin K-antagonists, DOACs are the preferred treatment option for the long term treatment of unprovoked venous thromboembolism. Apixaban is available in a reduced dose for long-term treatment, and rivaroxaban in a reduced dose was recently shown to be more effective than aspirin.

Continuation of low-molecular-weight heparin treatment for cancer-related venous thromboembolism: a prospective cohort study in daily clinical practice

Essentials Low-molecular-weight heparin (LMWH) injections for venous thromboembolism (VTE) may be burdensome. Patients with active cancer and confirmed VTE were included to evaluate LMWH continuation. The cumulative incidence of discontinuation was 21% after a median period of 90 days. One out of five patients discontinued LMWH injections because of side effects.

SUMMARY

Background Current guidelines recommend low-molecular-weight heparin (LMWH) monotherapy for 3-6 months as the first-line treatment for cancer-associated venous thromboembolism (VTE). However, although daily administration of LMWH injections over a course of several months may be burdensome, the number of patients who stop treatment because of LMWH side-effects is unknown. Objectives To evaluate the continuation rate and complications of daily LMWH injections in patients with cancer-associated VTE. Methods Consecutive patients with active cancer and objectively confirmed symptomatic proximal deep vein thrombosis and/or pulmonary embolism, treated at three Dutch hospitals and one Spanish hospital, were included to evaluate continuation LMWH therapy during LMWH treatment. Patients were excluded when they received other anticoagulants, were lost to follow-up, or experienced a venous catheter-associated thrombosis. Results A total of 372 patients were analyzed during LMWH treatment for a maximum of 180 days. The cumulative incidence of discontinuation was 21% (95% confidence interval [CI] 17-25) after a median period of 90 days (interquartile range 60-120 days). Only female sex was found to be significantly associated with premature LMWH discontinuation (odds ratio 1.6; 95% CI 1.03-2.5). Thirty patients (8.1%) developed recurrent VTE, 30 patients (8.3%) suffered a major bleed, and 106 patients (28%) died. Conclusion Our study reveals that one of five patients with cancer-associated VTE stopped LMWH injections because of side-effects. This finding provides relevant background information for current clinical trials investigating the efficacy and safety of direct oral anticoagulants as compared with LMWH.

The role of computed tomography in the diagnosis of acute and chronic pulmonary embolism

Pulmonary embolism (PE) is a potentially life threatening condition requiring adequate diagnosis and treatment. Computed tomography pulmonary angiography (CTPA) is excellent for including and excluding PE, therefore CT is the first-choice diagnostic imaging technique in patients suspected of having acute PE. Due to its wide availability and low invasiveness, CTPA tends to be overused. Correct implementation of clinical decision rules in diagnostic workup for PE improves adequate use of CT. Also, CT adds prognostic value by evaluating right ventricular (RV) function. CT-assessed RV dysfunction and to lesser extent central emboli location predicts PE-related mortality in normotensive and hypotensive patients, while PE embolic obstruction index has limited prognostic value. Simple RV/left ventricular (LV) diameter ratio measures >1.0 already predict risk for adverse outcome, whereas ratios <1.0 can safely exclude adverse outcome. Consequently, assessing the RV/LV diameter ratio may help identify patients who are potential candidates for treatment at home instead of treatment in the hospital. A minority of patients develop chronic thromboembolic pulmonary hypertension (CTEPH) following acute PE, which is a life-threatening condition that can be diagnosed by CT. In proximal CTEPH, involving the more central pulmonary arteries, thrombectomy usually results in good outcome in terms of both functional status and long-term survival rate. CT is becoming the imaging method of choice for diagnosing CTEPH as it can identify patients who may benefit from thrombectomy. New CT developments such as distensibility measurements and dual-energy or subtraction techniques may further refine diagnosis and prognosis for improved patient care.

Accurate diagnosis of iliac vein thrombosis in pregnancy with magnetic resonance direct thrombus imaging (MRDTI)

A pregnant woman aged 29 years, G1P0 at 21 weeks of gestation of a dichorionic diamniotic twin, presented with suspected deep vein thrombosis (DVT) of the left leg. Repeated (compression) ultrasonography was not diagnostic for DVT but showed reduced flow over the left external iliac vein, common femoral vein and superficial femoral vein. In pursue of a definite diagnosis, magnetic resonance direct thrombus imaging was performed showing a clear high signal in the left common iliac vein which is diagnostic for acute thrombosis in this venous segment. Phase contrast venography supported this diagnosis, showing no flow in the left common iliac vein. Treatment with anticoagulants was started. 6 months after the diagnosis, the patient is doing well and does not report signs of post-thrombotic syndrome.

Idarucizumab and Factor Xa Reversal Agents: Role in Hospital Guidelines and Protocols

As expected with all antithrombotic agents, there is a risk of bleeding complications in patients receiving direct oral anticoagulants (DOACs) because of the DOAC itself, acute trauma, invasive procedures, or underlying comorbidities. For many bleeding events, a prudent course of action will be to withdraw the DOAC, then "wait and support" the patient, with the expectation that the bleeding event should resolve with time. Likewise, DOAC therapy may be interrupted ahead of a planned procedure, the stopping time being dependent on the agent involved and the patient's renal function. However, urgent reversal of anticoagulation is required in patients with serious or life-threatening bleeding or in those requiring urgent surgery or procedures. Novel specific reversal agents, either under development or recently approved, will need to be incorporated into local anticoagulation reversal protocols. For dabigatran-treated patients, idarucizumab recently has been approved for clinical use in cases of life-threatening or uncontrolled bleeding or when patients require emergency surgery or urgent procedures, both associated with a high risk of bleeding. As clinical experience with individual specific reversal agents grows, their roles in managing major bleeding events in DOAC-treated patients will become better defined. Future research, as well as ongoing use of idarucizumab, should help establish when it is appropriate to re-dose with idarucizumab, co-administer with prothrombin complex concentrates, or re-initiate DOAC after idarucizumab use. Ongoing trials should help identify the appropriate doses and expected durations of effect for andexanet alfa and ciraparantag, which are likely to vary depending on the individual oral anticoagulants.

Current and future perspectives in imaging of venous thromboembolism

Several thrombus imaging techniques for the diagnosis of venous thromboembolism (VTE) are available. The most prevalent forms of VTE are deep vein thrombosis of the lower extremities and pulmonary embolism. However, VTE may also occur at unusual sites such as deep veins of the upper extremity and the splanchnic and cerebral veins. Currently, the imaging techniques most widely used in clinical practice are compression ultrasonography and computed tomography (CT) pulmonary angiography. Moreover, single-photon emission CT, CT venography, positron emission tomography, and different magnetic resonance imaging (MRI) techniques, including magnetic resonance direct thrombus imaging, have been evaluated in clinical studies. This review provides an overview of the technique, diagnostic accuracy and potential pitfalls of these established and emerging imaging modalities for the different sites of venous thromboembolism.

Wells Rule and d-Dimer Testing to Rule Out Pulmonary Embolism: A Systematic Review and Individual-Patient Data Meta-analysis

BACKGROUND

The performance of different diagnostic strategies for pulmonary embolism (PE) in patient subgroups is unclear.

PURPOSE

To evaluate and compare the efficiency and safety of the Wells rule with fixed or age-adjusted d-dimer testing overall and in inpatients and persons with cancer, chronic obstructive pulmonary disease, previous venous thromboembolism, delayed presentation, and age 75 years or older.

DATA SOURCES

MEDLINE and EMBASE from 1 January 1988 to 13 February 2016.

STUDY SELECTION

6 prospective studies in which the diagnostic management of PE was guided by the dichotomized Wells rule and quantitative d-dimer testing.

DATA EXTRACTION

Individual data of 7268 patients; risk of bias assessed by 2 investigators with the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2) tool.

DATA SYNTHESIS

The proportion of patients in whom imaging could be withheld based on a "PE-unlikely" Wells score and a negative d-dimer test result (efficiency) was estimated using fixed (≤500 µg/L) and age-adjusted (age × 10 µg/L in patients aged >50 years) d-dimer thresholds; their 3-month incidence of symptomatic venous thromboembolism (failure rate) was also estimated. Overall, efficiency increased from 28% to 33% when the age-adjusted (instead of the fixed) d-dimer threshold was applied. This increase was more prominent in elderly patients (12%) but less so in inpatients (2.6%). The failure rate of age-adjusted d-dimer testing was less than 3% in all examined subgroups.

LIMITATION

Post hoc analysis, between-study differences in patient characteristics, use of various d-dimer assays, and limited statistical power to assess failure rate.

CONCLUSION

Age-adjusted d-dimer testing is associated with a 5% absolute increase in the proportion of patients with suspected PE in whom imaging can be safely withheld compared with fixed d-dimer testing. This strategy seems safe across different high-risk subgroups, but its efficiency varies.

PRIMARY FUNDING SOURCE

None.

Familial Thrombophilia: A Review Analysis

The correct approach to the management of the asymptomatic carrier with a recognized inherited thrombophilic disorder is uncertain because reliable in formation of the risk of spontaneous (unprovoked) throm bosis in these disorders is not available. To determine the best available estimate of the annual incidence of spon taneous thrombosis in asymptomatic carriers of disorders that have been linked to familial thrombophilia, we per formed a literature review. Using Medline search from 1965 to 1992, supplemented by manual searches, we re trieved all articles that presented data on antithrombin III, protein C, protein S, dysfibrinogenemia, plasmino gen, histidine-rich glycoprotein, heparin cofactor II, and fibrinolysis in relation to thrombosis. Publications were included in the analysis if they (1) reported one or more probands with thrombotic disease and a heterozygous biochemical abnormality of the hemostatic system, (2) assessed the presence of this abnormality in family mem bers independent of the presence or absence of a history of thrombotic disease, and (3) assessed the presence of a history of thrombotic disease in all available family mem bers. The biochemical status and clinical details of all family members reported were extracted from each eligi ble article. For each abnormality the odds ratio for throm bosis was compared in family members with and without the biochemical abnormality. If applicable, thrombosis- free survival and age-specific incidences of thrombosis were calculated. The thrombotic episodes were classified as spontaneous or secondary to a recognized risk factor, and the proportion of spontaneous episodes was calcu lated. The influence of diagnostic suspicion bias in symp tomatic patients with a family history of thrombosis was reduced by recalculating the absolute incidence of throm bosis from the odds ratio after adjusting the incidence of venous thrombosis in nonaffected family members to that observed in the general population. Statistically signifi cant associations between the presence of a biochemical abnormality and a history of venous thrombosis were found for antithrombin III deficiency types 1 and 2a and 2b, protein C deficiency type 1, and protein S deficiency type I. Dysfibronogenemia was statistically significantly associated with venous as well as arterial thrombosis. Thirty-five to 67% of the events were classified as being provoked, as they occurred following exposure to a rec ognized risk factor for thrombosis. The recalculated an nual incidence of spontaneous thrombosis was 0.6 to 1.6%/year. It is concluded that this relatively low inci dence does not warrant life-long continuous use of anti coagulant prophylaxis since the reported risk of major and fatal bleeding associated with the use of oral antico agulants is 2-3 and 0.4%/year, respectively.

Antithrombotic therapy use in patients with atrial fibrillation before the era of non-vitamin K antagonist oral anticoagulants: the Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF) Phase I cohort

AIMS

The introduction of non-VKA oral anticoagulants (NOACs), which differ from the earlier vitamin K antagonist (VKA) treatments, has changed the approach to stroke prevention in atrial fibrillation (AF). GLORIA-AF is a prospective, global registry programme describing the selection of antithrombotic treatment in newly diagnosed AF patients at risk of stroke. It comprises three phases: Phase I, before the introduction of NOACs; Phase II, during the time of the introduction of dabigatran, the first NOAC; and Phase III, once NOACs have been established in clinical practice.

METHODS AND RESULTS

In Phase I, 1063 patients were eligible from the 1100 enrolled (54.3% male; median age 70 years); patients were from China (67.1%), Europe (EU; 27.4%), and the Middle East (ME; 5.6%). The majority of patients using VKAs had high stroke risk (CHA2DS2-VASc ≥ 2; 86.5%); 13.5% had moderate risk (CHA2DS2-VASc = 1). Vitamin K antagonist use was higher for persistent/permanent AF (47.7%) than that for paroxysmal (23.9%). Most patients in China were treated with antiplatelet agents (53.7%) vs. 27.1% in EU and 28.8% in ME. In China, 25.9% of patients had no antithrombotic therapy, vs. 8.6% in EU and 8.5% in ME.

CONCLUSION

Phase I of GLORIA-AF shows that VKAs were mostly used in patients with persistent/permanent (vs. paroxysmal) AF and in those with high stroke risk. Furthermore, there were meaningful geographical differences in the use of VKA therapy in the era before the availability of NOACs, including a much lower use of VKAs in China, where most patients either received antiplatelet agents or no antithrombotic treatment.

One versus two years of elastic compression stockings for prevention of post-thrombotic syndrome (OCTAVIA study): randomised controlled trial

OBJECTIVE

 To study whether stopping elastic compression stockings (ECS) after 12 months is non-inferior to continuing them for 24 months after proximal deep venous thrombosis.

DESIGN

 Multicentre single blind non-inferiority randomised controlled trial.

SETTING

 Outpatient clinics in eight teaching hospitals in the Netherlands, including one university medical centre.

PARTICIPANTS

 Patients compliant with compression therapy for 12 months after symptomatic, ultrasound proven proximal deep venous thrombosis of the leg.

INTERVENTIONS

 Continuation or cessation of ECS 12 months after deep venous thrombosis.

MAIN OUTCOME MEASURES

 The primary outcome was the incidence of post-thrombotic syndrome 24 months after diagnosis of deep venous thrombosis, as assessed by the standardised Villalta scale in an intention to treat analysis. The predefined non-inferiority margin was 10%. The main secondary outcome was quality of life (VEINES-QOL/Sym).

RESULTS

 518 patients compliant with ECS and free of post-thrombotic syndrome were randomised one year after diagnosis of deep venous thrombosis to stop or continue ECS therapy for another year. In the stop-ECS group, 51 of 256 patients developed post-thrombotic syndrome, with an incidence of 19.9% (95% confidence interval 16% to 24%). In the continue-ECS group, 34 of 262 patients developed post-thrombotic syndrome (incidence 13.0%, 9.9% to 17%), of whom 85% used ECS six or seven days a week during the study period, for an absolute difference of 6.9% (95% confidence interval upper limit 12.3%). Because the upper limit of the 95% confidence interval exceeds the predefined margin of 10%, non-inferiority was not reached. The number needed to treat to prevent one case of post-thrombotic syndrome by continuing ECS was 14 (95% confidence interval lower limit 8). Quality of life did not differ between the two groups.

CONCLUSION

 Stopping ECS after one year in compliant patients with proximal deep venous thrombosis seemed not to be non-inferior to continuing ECS therapy for two years in this non-inferiority trial.

TRIAL REGISTRATION

 Netherlands Trial Register NTR1442.

Association between micro particle-tissue factor activity, factor VIII activity and recurrent VTE in patients with acute pulmonary embolism

Studies on the association between microparticle expressing tissue factor (MP-TF) activity, FVIII activity (FVIII:C) and recurrent VTE yielded inconclusive results. We studied these associations in patients diagnosed with acute pulmonary embolism. Plasma levels of MP-TF and FVIII activity were measured in 277 patients with a first and 72 patients with a recurrent VTE. All patients were categorized based on the quintiles of MP-TF and FVIII activity in those with a single VTE. For both markers, odds ratios (ORs) for recurrent VTE were computed using patients in the lowest quintile as a reference group. No association was observed between MP-TF activity and recurrent VTE, with an OR of 1.4 (95 % CI 0.7–2.9) in the highest quintile of MP-TF activity. Compared with the reference group, patients in the highest quintile of FVIII:C were at increased risk of recurrent VTE, OR 4.2 (95 % CI 1.4–12.2). MP-TF activity was not associated with recurrent VTE whereas high FVIII:C levels were associated with a 4-fold increased risk of VTE recurrence. Future prospective studies are necessary to explore the potential of FVIII:C as a tool for risk stratification, either by itself or in combination with other pro-thrombotic markers.

PO-07 - Excluding pulmonary embolism in cancer patients using the Wells rule and age-adjusted D-dimer testing: an individual patient data meta-analysis

INTRODUCTION

Among patients with clinically suspected pulmonary embolism (PE), imaging and anticoagulant treatment can be safely withheld in approximately one-third of patients based on the combination of a "PE unlikely" Wells score and a D-dimer below the age-adjusted threshold. The clinical utility of this diagnostic approach in cancer patients is less clear.

AIM

To evaluate the efficiency and failure rate of the original and simplified Wells rules in combination with age-adjusted D-dimer testing in patients with active cancer.

MATERIALS AND METHODS

Individual patient data were used from 6 large prospective studies in which the diagnostic management of PE was guided by the original Wells rule and D-dimer testing. Study physicians classified patients as having active cancer if they had new, recurrent, or progressive cancer (excluding basal-cell or squamous-cell skin carcinoma), or cancer requiring treatment in the last 6 months. We evaluated the dichotomous Wells rule and its simplified version (Table). The efficiency of the algorithm was defined as the proportion of patients with a "PE unlikely" Wells score and a negative age-adjusted D-dimer, defined by a D-dimer below the threshold of a patient's age times 10 μg/L in patients aged ≥51 years. A diagnostic failure was defined as a patient with a "PE unlikely" Wells score and negative age-adjusted D-dimer who had symptomatic venous thromboembolism during 3 months follow-up. A one-stage random effects meta-analysis was performed to estimate the efficiency and failure.

RESULTS

The dataset comprised 938 patients with active cancer with a mean age of 63 years. The most frequent cancer types were breast (13%), gastrointestinal tract (11%), and lung (8%). The type of cancer was not specified in 42%. The pooled PE prevalence was 29% (95% CI 25-32). PE could be excluded in 122 patients based on a "PE unlikely" Wells score and a negative age-adjusted D-dimer (efficiency 13%; 95% CI 11-15). Two of 122 patients were diagnosed with non-fatal symptomatic venous thromboembolism during follow-up (failure rate 1.5%; 95% CI 0.13-14.8). The simplified Wells score in combination with a negative age-adjusted D-dimer had an efficiency of 3.9% (95% CI 2.0-7.6) and a failure rate of 2.4% (95% CI 0.3-15).

CONCLUSIONS

Among cancer patients with clinically suspected PE, imaging and anticoagulant treatment can be withheld in 1 out of every 8 patients by the original Wells rule and age-adjusted D-dimer testing. The simplified Wells rule was neither efficient nor safe in this population.

Coronary or thoracic artery calcium score in provoked and unprovoked pulmonary embolism: a case-control study

Essentials Patients with unprovoked pulmonary embolism (PE) are at increased risk of arterial thromboembolism. Coronary and thoracic aorta calcium were evaluated in patients with and without (unprovoked) PE. No association was found between (unprovoked) PE and coronary or aortic calcification. Assessment of both calcium scores on computed tomography pulmonary angiography was highly reproducible.

SUMMARY

Objective To evaluate the potential association between (unprovoked) pulmonary embolism (PE) and the presence and extent of coronary artery calcium (CAC) and thoracic aorta calcium (TAC). Methods CAC and TAC derived from computed tomography pulmonary angiography of 100 patients with PE were compared to that of 100 patients in whom PE was ruled out. Results Intraobserver and interobserver agreements for both TAC and CAC were excellent (intraclass correlation > 0.95 for both). In patients with PE vs. patients without PE, no significant differences were found in the presence of CAC or TAC (CAC 64% vs. 67%, odds ratio [OR] 1.0, 95% confidence interval [CI] 0.67-1.6; TAC 46% vs. 59%, OR 1.2, 95% CI 0.80-2.1). Mean CAC and TAC scores were significantly lower in patients with PE than in patients without PE (CAC 3.4 vs. 4.9, absolute difference 1.5, 95% CI 0.2-2.8; TAC 1.1 vs. 1.8, absolute difference 0.9, 95% CI 0.2-1.2). No significant differences were found in the presence of CAC or TAC or in mean CAC and TAC scores between patients with unprovoked PE vs. patients with provoked PE, or between patients with unprovoked PE vs. no PE. Conclusion No significant differences were found between the extent of CAC and TAC in patients with unprovoked PE compared to those with provoked PE or without PE. The observed difference in the extend of CAC and TAC between patients with and without PE was dependent on prevalent cardiovascular risk factors.

Efficacy of prothrombin complex concentrates for the emergency reversal of dabigatran-induced anticoagulation

Dabigatran is effective in decreasing the risk of ischaemic stroke in patients with atrial fibrillation. However, like all anticoagulants, it is associated with a risk of bleeding. In cases of trauma or emergency surgery, emergency reversal of dabigatran-induced anticoagulation may be required. A specific reversal agent for dabigatran, idarucizumab, has been approved by the US Food and Drug Administration. Alternative reversal agents are available, such as prothrombin complex concentrates (PCCs) and activated PCCs (aPCCs). In this review we evaluate the role of PCCs and aPCCs in the reversal of dabigatran anticoagulation and consider which tests are appropriate for monitoring coagulation in this setting. Pre-clinical studies, small clinical studies and case reports indicate that PCCs and aPCCs may be able to reverse dabigatran-induced anticoagulation in a dose-dependent manner. However, dosing based on coagulation parameters can be difficult because available assays may not provide adequate sensitivity and specificity for measuring anticoagulation induced by dabigatran or the countering effects of PCCs/aPCCs. In addition, PCCs or aPCCs can potentially provoke thromboembolic complications. Despite these limitations and the fact that PCCs and aPCCs are not yet licensed for dabigatran reversal, their use appears to be warranted in patients with life-threatening haemorrhage if idarucizumab is not available.

CV, Weitz JI, Reilly PA, Eikelboom J, Huisman MV, Kamphuisen PW, Kreuzer J, Levy JH, Steiner T. Abstract 213: Effect of Idarucizumab on Intracranial Bleeding in Dabigatran-treated Patients: Initial Results From RE-VERSE AD

Introduction: Dabigatran is a non-vitamin K antagonist oral anticoagulant (NOAC) licensed for stroke prevention in nonvalvular atrial fibrillation. In the RE-LY trial, both doses of dabigatran (110 mg and 150 mg bid) were associated with a significantly lower annualized rate of intracranial hemorrhage (ICH) than warfarin (0.23%, 0.32% and 0.76%, respectively). Nonetheless, the mortality rate with ICH in the context of any anticoagulation remains high, probably reflecting the effects of hematoma expansion. Whether a specific reversal agent for dabigatran will improve clinical outcomes in dabigatran-treated patients with ICH is unknown. RE-VERSE AD is an ongoing, open-label, phase 3, cohort study evaluating the extent to which idarucizumab, a humanized Fab fragment directed against dabigatran, reverses the latter’s anticoagulant effects in patients with serious bleeding or in those requiring urgent interventions. This study focuses on the results in patients with ICH.

Hypothesis: Compared with historical controls, idarucizumab improves clinical outcomes in dabigatran-treated patients with ICH.

Methods: Patients presenting with ICH were given intravenous idarucizumab 5 g as two 2.5 g bolus infusions administered no more than 15 minutes apart. The primary endpoint was the maximum reversal of the anticoagulant effect of dabigatran, based on central laboratory determination of the dilute thrombin time or ecarin clotting time.

Results: In an interim analysis at 90 patients, 18 with ICH had been enrolled in RE-VERSE AD. Updated results on the effects of idarucizumab on coagulation parameters, imaging studies, and clinical outcomes in this patient subgroup will be presented.

Conclusions: Currently, there are no specific reversal agents for the NOACs. We present the first data on the clinical outcomes for idarucizumab in dabigatran-treated patients who present with ICH.

Abstract TP428: Antithrombotic Therapy in Patients With Atrial Fibrillation and Prior Stroke in GLORIA- AF Phase II (Global Registry on Long-term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation, Phase II)

Introduction: Given their substantial risk of recurrent stroke, patients with atrial fibrillation (AF) and prior stroke are at highest risk. Such patients should be pre-scribed oral anticoagulants (OAC), either a Vitamin K Antagonist (VKA) or Non-VKA OAC (NOAC).

Methods: Using an inception cohort design, GLORIA-AF collected data on choice of antithrombotic therapy for patients with newly identified AF at risk of stroke (CHA2DS2VASc scores ≥ 1) in the course of routine care. We examined the use of an-tithrombotic therapy in those with prior stroke.

Results: From 15,092 patients in Phase II of GLORIA-AF enrolled in 5 geographical regions worldwide (Europe, North America, Asia, Latin America and Africa/Middle East), 1,582 patients (median age 75 years, 54.9% male) had previous stroke, with a median CHA2DS2-VASc score of 5, compared with a score of 3 in those without previ-ous stroke (n=13,500). For 10 patients previos stroke status was unknown.

In those with previous stroke, VKA alone was prescribed in 25.2%, VKA plus an-tiplatelet therapy (AP) in 5.8%, NOAC alone in 42.9%, NOAC plus AP in 7.7%, and AP alone in 12.1%; 6.3% received no antithrombotic therapy. Proportions were broadly similar in males and females. In comparison, among patients without prior stroke the proportions on AP only or no therapy were a little higher (20.2 versus 18.3%). Among those with prior stroke, proportions on AP alone in Asia, Europe, and North America were 24.2, 9.9 and 5.6% respectively, while proportions on no antithrombotic therapy in these regions were 16.3, 3.2 and 4.5%.

Conclusion: In this prospective registry, AF patients with prior stroke and a median CHA2DS2-VASc score of 5, approximately 18% were treated with AP alone or no an-tithrombotic therapy, and the treatment gap was greater in Asia than in Europe or North America.

Cohort Study on the Management of Cancer-Associated Venous Thromboembolism Aimed at the Safety of Stopping Anticoagulant Therapy in Patients Cured of Cancer

BACKGROUND

After diagnosis of cancer-associated VTE, guidelines recommend considering the continuation of anticoagulant treatment until the patient is cured of cancer, although the safety of stopping anticoagulant treatment after the patient is cured has never been evaluated.

METHODS

We conducted a cohort study in consecutive patients in whom cancer-associated VTE was diagnosed at the Leiden University Medical Center between January 2001 and January 2010 and monitored for the effect of cancer treatment, occurrence of recurrent VTE, major hemorrhage, and death.

RESULTS

Of the 358 patients with cancer-associated VTE, anticoagulant treatment was continued until the death of 207 patients. In another 12 patients anticoagulant treatment was continued because of an alternative indication despite their being cured of cancer. Anticoagulant treatment was stopped in 50 patients for reasons other than major hemorrhage despite active cancer, in 21 patients after major hemorrhage, and in 68 patients after they had been cured of cancer. Among these 68 patients, 10 patients received a diagnosis of symptomatic recurrent VTE during a cumulative follow-up of 311 years, resulting in an incidence rate of 3.2 per 100 patient-years (95% CI, 1.5-5.9). Seven of these 10 patients with recurrent VTE experienced a cancer relapse during follow-up. For the 50 patients who stopped anticoagulant treatment despite active cancer the recurrent VTE incidence rate was 19 per 100 patient-years (11 events during 59 years of follow-up; 95% CI, 9.3-33).

CONCLUSIONS

Our data support the recommendation to stop anticoagulant treatment of cancer-associated VTE in patients cured of cancer. A cancer relapse seems to be a strong risk factor for recurrent symptomatic VTE.

[Assessment of bleeding risk in patients with venous thromboembolism: we are still a long way from home]

Recent American, European and Dutch guidelines recommend lifelong anticoagulation after a diagnosis of unprovoked venous thromboembolism (VTE) in the absence of high bleeding risk. Major bleeding events may, however, be devastating, and are reported to have a higher case fatality rate than recurrent venous thromboembolism itself. Unfortunately, there are no validated risk assessment tools for major bleeding that help physicians determine the optimal duration of anticoagulant therapy after VTE. Furthermore, the scarce studies on this subject have focused on vitamin K antagonist treatment regimens only, covering mainly the initial weeks and first month, during which period the level of anticoagulation is unstable. New studies focusing on bleeding risk during the 'chronic' treatment period with modern anticoagulants, i.e. the direct oral anticoagulants or 'DOACs', are urgently needed. Until these are available, the 2016 Dutch guideline on anticoagulation therapy provides a table with a summary of known individual risk factors that can be applied in clinical practice.

Recent developments in the diagnosis and treatment of pulmonary embolism

Due to the nonspecific symptoms of the condition, a diagnosis of acute pulmonary embolism (PE) is frequently considered. However, PE will only be confirmed in 10-20% of patients. Because the imaging test of choice, computed tomography pulmonary angiography (CTPA), is costly and associated with radiation exposure and other complications, a validated diagnostic algorithm consisting of a clinical decision rule and D-dimer test should be used to safely exclude PE in 20-30% of patients without the need for CTPA. Recently, the age-adjusted D-dimer threshold has been validated, and this has increased the proportion of patients at older age in whom PE can be excluded without CTPA. Initial therapeutic management of PE depends on the risk of short-term PE-related mortality. Haemodynamically unstable patients should be closely monitored and receive thrombolytic therapy unless contraindicated because of an unacceptably high bleeding risk, whereas patients with low-risk PE may be safely discharged early from hospital or receive only outpatient treatment. The PESI score and Hestia decision rule are available to select patients in whom early discharge or outpatient treatment will be safe, although the safety of these strategies should be confirmed in additional studies. Standard PE therapy consists of low molecular weight heparin (LMWH) followed by vitamin K antagonists (VKAs). Recently, several nonvitamin K-dependent oral anticoagulants have been shown to be as effective as LMWH/VKAs, and maybe safer. Determining the optimal duration of treatment for a first unprovoked PE remains a challenge, although clinical prediction rules for estimating the risk of recurrence of venous thromboembolism and anticoagulation-associated haemorrhage are under investigation. Using these prediction rules may lead to both more standardized and more individualized long-term treatment of PE.