[Translation into French and republication of: "Management of cancer-associated thromboembolism in vulnerable population"]

Although all patients with cancer-associated thrombosis (CAT) have a high morbidity and mortality risk, certain groups of patients are particularly vulnerable. This may expose the patient to an increased risk of thrombotic recurrence or bleeding (or both), as the benefit-risk ratio of anticoagulant treatment may be modified. Treatment thus needs to be chosen with care. Such vulnerable groups include older patients, patients with renal impairment or thrombocytopenia, and underweight and obese patients. However, these patient groups are poorly represented in clinical trials, limiting the available data on which treatment decisions can be based. Meta-analysis of data from randomised clinical trials suggests that the relative treatment effect of direct oral factor Xa inhibitors (DXIs) and low molecular weight heparin (LMWH) with respect to major bleeding could be affected by advanced age. No evidence was obtained for a change in the relative risk-benefit profile of DXIs compared to LMWH in patients with renal impairment or of low body weight. The available, albeit limited, data do not support restricting the use of DXIs in patients with TAC on the basis of renal impairment or low body weight. In older patients, age is not itself a critical factor for choice of treatment, but frailty is such a factor. Patients over 70 years of age with CAT should undergo a systematic frailty evaluation before choosing treatment and modifiable bleeding risk factors should be addressed. In patients with renal impairment, creatine clearance should be assessed and monitored regularly thereafter. In patients with an eGFR less than 30mL/min/1.72m2, the anticoagulant treatment may need to be adapted. Similarly, platelet count should be assessed prior to treatment and monitored regularly. In patients with grade 3-4, thrombocytopenia (less than 50,000platelets/μL) treatment with a LMWH at a reduced dose should be considered. For patients with CAT and low body weight, standard anticoagulant treatment recommendations are appropriate, whereas in obese patients, apixaban may be preferred.

[Translation into French and republication of: "Management of venous thromboembolic disease in patients with malignant brain tumours"]

This article addresses the management of venous thromboembolism in patients with malignant brain tumours, including both primary and secondary (metastatic) tumours. The available data on patients on venous thromboembolism recurrence and bleeding risks in patients with brain tumours is limited, since these patients have been excluded from most randomised, interventional, head-to-head, clinical trials comparing low molecular weight heparins to vitamin K antagonists or to direct oral factor Xa inhibitors. More information is available from retrospective observational studies, which however were generally small, and carried a high risk of confounding. Their findings suggest that direct factor Xa inhibitor use is associated with lower rates of intracranial haemorrhage compared with low molecular weight heparins. Overall, the safety profile of direct oral factor Xa inhibitors when used to prevent venous thromboembolism recurrence in patients with either primary or secondary brain tumours appears to be favourable. The available data are in favour of using an anticoagulant at a full therapeutic dose in patients with primary and secondary brain tumours experiencing a venous thromboembolism, although they are not yet sufficiently robust to permit recommending a direct factor Xa inhibitor over low-molecular weight heparin.

Management of cancer-associated thromboembolism in vulnerable population

Although all patients with cancer-associated thrombosis (CAT) have a high morbidity and mortality risk, certain groups of patients are particularly vulnerable. This may expose the patient to an increased risk of thrombotic recurrence or bleeding (or both), as the benefit-risk ratio of anticoagulant treatment may be modified. Treatment thus needs to be chosen with care. Such vulnerable groups include older patients, patients with renal impairment or thrombocytopenia, and underweight and obese patients. However, these patient groups are poorly represented in clinical trials, limiting the available data, on which treatment decisions can be based. Meta-analysis of data from randomised clinical trials suggests that the relative treatment effect of direct oral factor Xa inhibitors (DXIs) and low molecular weight heparin (LMWH) with respect to major bleeding could be affected by advanced age. No evidence was obtained for a change in the relative risk-benefit profile of DXIs compared to LMWH in patients with renal impairment or of low body weight. The available, albeit limited, data do not support restricting the use of DXIs in patients with CAT on the basis of renal impairment or low body weight. In older patients, age is not itself a critical factor for choice of treatment, but frailty is such a factor. Patients over 70 years of age with CAT should undergo a systematic frailty evaluation before choosing treatment and modifiable bleeding risk factors should be addressed. In patients with renal impairment, creatine clearance should be assessed and monitored regularly thereafter. In patients with an eGFR<30mL/min/1.72m2, the anticoagulant treatment may need to be adapted. Similarly, platelet count should be assessed prior to treatment and monitored regularly. In patients with grade 3-4, thrombocytopenia (<50,000 platelets/μL) treatment with a LMWH at a reduced dose should be considered. For patients with CAT and low body weight, standard anticoagulant treatment recommendations are appropriate, whereas in obese patients, apixaban may be preferred.

Venous thromboembolism prophylaxis and multiple myeloma patients in real-life: Results of a large survey and clinical guidance recommendations from the IFM group

Venous thromboembolism (VTE) remains a critical issue in the management of patients with multiple myeloma (MM), particularly when immunomodulatory drugs (IMiDs) combined with dexamethasone therapy are being prescribed as first-line and relapse therapy. One possible explanation for the persistent high rates of VTE, is the use of inappropriate thromboprophylaxis strategies for patients starting antimyeloma treatment. To tackle the issue, the Intergroupe francophone du myélome (IFM) offered convenient guidance for VTE thromboprophylaxis in MM patients initiating systemic therapy. This guidance is mainly supported by the results of a large survey on the clinical habits regarding VTE of physicians who are substantially involved in daily care of MM patients. VTE prophylaxis should be considered for all patients treated with IMiDs in combination with dexamethasone, in the absence of significant comorbidities, such as renal failure or bleeding risk. Anticoagulant should be preferred to antiplatelet agents for thromboprophylaxis. Despite the absence of large randomized controlled trials comparing those attitudes/options, available data on direct oral anticoagulants, which are already used in daily management of MM patients, are consistent with their potential usefulness for VTE prophylaxis in such patients. However, in order to implement a personalized continuous improvement strategy, clinicians must to be organized to collect all the data regarding this management. In other situations, thromboprophylaxis should be evaluated by using risk models and after careful evaluation of the risk/benefit ratio.

Management of venous thromboembolic disease in patients with malignant brain tumours

This article addresses the management of venous thromboembolism in patients with malignant brain tumours, including both primary and secondary (metastatic) tumours. The available data on patients on venous thromboembolism recurrence and bleeding risks in patients with brain tumours is limited, since these patients have been excluded from most randomised, interventional, head-to-head, clinical trials comparing low molecular weight heparins to vitamin K antagonists or to direct oral Factor Xa inhibitors. More information is available from retrospective observational studies, which however were generally small, and carried a high risk of confounding. Their findings suggest that direct Factor Xa inhibitor use is associated with lower rates of intracranial haemorrhage compared with low molecular weight heparins. Overall, the safety profile of direct oral Factor Xa inhibitors when used to prevent venous thromboembolism recurrence in patients with either primary or secondary brain tumours appears to be favourable. The available data are in favour of using an anticoagulant at a full therapeutic dose in patients with primary and secondary brain tumours experiencing a venous thromboembolism, although they are not yet sufficiently robust to permit recommending a direct Factor Xa inhibitor over low-molecular weight heparin.

Long-Term Cangrelor Administration in Neurology Intensive Care: A Case Series

Cangrelor is a P2Y12 inhibitor antiplatelet agent, with a rapid onset and offset. The available literature only reviews short-term administration over a few hours. We describe 5 patients who received cangrelor for >1 month in a neurosurgical intensive care unit due to a very high likelihood of requiring emergency revision surgery. Despite multiple therapeutic interruptions for surgical procedures, no hemorrhagic events occurred, and there was only one transient ischemic event, which occurred during transition from cangrelor to ticagrelor. Cangrelor can be a therapeutic option for patients with a high likelihood of requiring revision neurosurgery after intracranial stenting.

FCGR2A-HH Gene Variants Encoding the Fc Gamma Receptor for the C-Reactive Protein Are Associated with Enhanced Monocyte CD32 Expression and Cardiovascular Events’ Recurrence after Primary Acute Coronary Syndrome

Fcγ receptors (FcγRs) interact with the C-reactive protein (CRP) and mediate activation of inflammation-related pathogenic mechanisms affecting cardiovascular health. Our study evaluated whether FcγRIIA and FcγRIIIA profiles are associated with the recurrence of adverse cardiovascular events during the first year after a primary acute coronary syndrome (ACS). The primary endpoint was the recurrence of cardiovascular events (RCE), identified as a composite outcome comprising acute heart failure (AHF) and major adverse cardiovascular events (MACE). We obtained blood samples of 145 ACS patients to measure hsCRP circulating levels, to identify FcγRIIA-131RH rs1801274 and FcγRIIIA-158FV rs396991 polymorphisms, to analyze circulating monocytes and NK cell subsets expressing CD16 and CD32, and to detect serum-mediated FCGR2A-HH activation by luciferase reporter assays. The hsCRP, CD32-expression, and Fc-R mediated activation levels were similar in all patients regardless of their MACE risk. In contrast, the hsCRP levels and the proportion of CD14+ circulating monocytes expressing the CD32 receptor for CRP were significantly higher in the patients who developed AHF. The FCGR2A rs1801274 HH genotype was significantly more common in patients who developed RCE and MACE than in RCE-free patients and associated with an enhanced percentage of circulating CD32+CD14+ monocytes. The FCGR2A-HH genotype was identified as an independent predictor of subsequent RCE (OR, 2.7; p = 0.048; CI, 1.01–7.44) by multivariate analysis. These findings bring preliminary evidence that host FCGR2A genetic variants can influence monocyte CD32 receptor expression and may contribute to the fine-tuning of CD32-driven chronic activating signals that affect the risk of developing RCEs following primary ACS events.

Endothelial cell biomarkers in critically ill COVID-19 patients with encephalitis

COVID-19 is associated with encephalitis in critically ill patients and endothelial dysfunction seems to contribute to this life-threatening complication. Our objective was to determine the hallmark of endothelial activation in COVID-19-related encephalitis. In an observational study in intensive care unit (ICU), we compared vascular biomarkers of critically ill COVID-19 patients with or without encephalitis. To be classified in the encephalitis group, patients had to have new onset of central neurologic symptom, and pathological findings on either brain magnetic resonance imaging (MRI) and/or electroencephalogram (EEG). Among the 32 critically ill COVID-19 consecutive patients, 21 were categorized in the control group and 11 in the encephalitis group. Encephalitis patients had a longer ICU stay than control patients (median length [25th-75th percentile] of 52 [16-79] vs. 20.5 [11-44] days, respectively, p = 0.04). Nine-month overall follow-up mortality reached 21% (7/32 patients), with mortality rates in the encephalitis group and the control group of 27% and 19%, respectively. Encephalitis was associated with significant higher release of soluble endothelial activation markers (sE-selectin, tumor necrosis factor-α (TNF-α), interleukin 6, placental growth factor, and thrombomodulin), but these increases were correlated with TNF-α plasmatic levels. The hypoxia-inducible protein angiopoietin-like 4 (ANGPTL4) was at significantly higher levels in encephalitis patients compared to control patients (p = 0.0099), and in contrary to the other increased factors, was not correlated with TNF-α levels (r = 0.2832, p = 0.1163). Our findings suggest that COVID-19-related encephalitis is a cytokine-associated acute brain dysfunction. ANGPTL4 was the only elevated marker found in encephalitis patients, which was not correlated with systemic inflammation, suggesting that ANGPTL4 might be a relevant factor to predict encephalitis in critically ill COVID-19 patients.

GFHT Proposals On The Practical Use Of Argatroban - With Specifics Regarding Vaccine-Induced Immune Thrombotic Thrombocytopaenia (VITT)

Argatroban is a direct anti-IIa (thrombin) anticoagulant, administered as a continuous intravenous infusion; it has been approved in many countries for the anticoagulant management of heparin-induced thrombocytopaenia (HIT). Argatroban was recently proposed as the non-heparin anticoagulant of choice for the management of patients diagnosed with Vaccine-induced Immune Thrombotic Thrombocytopaenia (VITT). Immunoglobulins are also promptly intravenously administered in order to rapidly improve platelet count; concomitant therapy with steroids is also often considered. An ad hoc committee of the French Working Group on Haemostasis and Thrombosis members has worked on updated and detailed proposals regarding the management of anticoagulation with argatroban, based on previously released guidance for HIT, and adapted for VITT. In case of VITT, the initial dose to be preferred is 1.0 µg x kg^-1 x min^-1, with further dose-adjustments based on iterative and frequent clinical and laboratory assessments. It is strongly advised to involve a health practitioner experienced in the management of difficult cases in haemostasis. The first laboratory assessment should be performed 4 hours after the initiation of argatroban infusion, with further controls at 2-4-hour intervals until steady state, and at least once daily thereafter. Importantly, full anticoagulation should be rapidly achieved in case of widespread thrombosis. Cerebral vein thrombosis (which is typical of VITT) should not call for an overly cautious anticoagulation scheme. Argatroban administration requires baseline laboratory assessment and should rely on an anti-IIa assay to derive argatroban plasma levels using a dedicated calibration, with a target range between 0.5 and 1.5 µg/mL. Target argatroban plasma levels can be refined based on meticulous appraisal of risk factors for bleeding and thrombosis, on frequent reassessments of clinical status with appropriate vascular imaging, and on the changes in daily platelet counts. Regarding the use of aPTT, baseline value and possible causes for alterations of the clotting time must be taken into account. Specifically, in case of VITT, an aPTT ratio (patient's / mean normal clotting time) between 1.5 and 2.5 is suggested, to be refined according to the sensitivity of the reagent to the effect of a direct thrombin inhibitor. The sole use of aPTT is discouraged: one has to resort to a periodical check with an anti-IIa assay at least, with the help of a specialised laboratory if necessary. Dose modifications should proceed in a stepwise manner with 0.1 to 0.2 µg x kg^-1 x min^-1 up- or downward changes, taking into account the initial dose, laboratory results, and the whole individual setting. Nomograms are available to adjust the infusion rate. Haemoglobin level, platelet count, fibrinogen plasma level and liver tests should be periodically checked, depending on the clinical status, the more so when unstable.

Viscoelastometric Testing to Assess Hemostasis of COVID-19: A Systematic Review

Infection by SARS-CoV-2 is associated with a high risk of thrombosis. The laboratory documentation of hypercoagulability and impaired fibrinolysis remains a challenge. Our aim was to assess the potential usefulness of viscoelastometric testing (VET) to predict thrombotic events in COVID-19 patients according to the literature. We also (i) analyzed the impact of anticoagulation and the methods used to neutralize heparin, (ii) analyzed whether maximal clot mechanical strength brings more information than Clauss fibrinogen, and (iii) critically scrutinized the diagnosis of hypofibrinolysis. We performed a systematic search in PubMed and Scopus databases until 31st December 2020. VET methods and parameters, and patients' features and outcomes were extracted. VET was performed for 1063 patients (893 intensive care unit (ICU) and 170 non-ICU, 44 studies). There was extensive heterogeneity concerning study design, VET device used (ROTEM, TEG, Quantra and ClotPro) and reagents (with non-systematic use of heparin neutralization), timing of assay, and definition of hypercoagulable state. Notably, only 4 out of 25 studies using ROTEM reported data with heparinase (HEPTEM). The common findings were increased clot mechanical strength mainly due to excessive fibrinogen component and impaired to absent fibrinolysis, more conspicuous in the presence of an added plasminogen activator. Only 4 studies out of the 16 that addressed the point found an association of VETs with thrombotic events. So-called functional fibrinogen assessed by VETs showed a variable correlation with Clauss fibrinogen. Abnormal VET pattern, often evidenced despite standard prophylactic anticoagulation, tended to normalize after increased dosing. VET studies reported heterogeneity, and small sample sizes do not support an association between the poorly defined prothrombotic phenotype of COVID-19 and thrombotic events.

[Differences of characteristics and outcomes between cancer patients and patients with no active cancer hospitalised for a SARS-CoV-2 infection]

Introduction

Les patients ayant un cancer solide ou hématologique ont été considérés comme étant plus susceptibles de contracter une infection à SARS-COV-2, et de développer plus fréquemment des complications graves. Nous avons voulu comparer les caractéristiques cliniques et le pronostic des patients atteints de COVID-19 avec ou sans cancer.

Méthodes

Il s’agit d’une étude observationnelle de cohorte prospective, de tous les patients hospitalisés consécutivement dans une unité dédiée aux patients atteints de COVID-19 à l’hôpital de la Pitié-Salpêtrière à Paris, entre le 16 mars et le 26 avril 2020.

Résultats

Parmi les 262 patients hospitalisés pour un diagnostic de COVID-19 dans cette unité lors de la première vague de la pandémie, 62 étaient également suivis pour un cancer solide ou hématologique actif. Il n’y avait pas de différence significative entre les deux groupes en ce qui concerne leurs caractéristiques cliniques, les comorbidités, ou leur pronostic entre ces deux groupes. On retrouvait cependant significativement plus de patients qui avaient une lymphopénie (médiane (IQ) : 0,7 (0,5–1,1) versus 0,9 (0,7–1,3)), et qui avaient été contaminés en milieu hospitalier (35,5 % versus 18 %, p = 0,008).

Conclusions

Les patients oncologiques et non oncologiques hospitalisés pour COVID-19 présentaient des résultats similaires en termes de décès, d’admission en soins intensifs ou de thrombose/hémorragie. Ils devraient bénéficier de la même stratégie thérapeutique similaire à que la population générale pendant la pandémie de COVID-19.

On-Ticagrelor Platelet Reactivity and Clinical Outcome in Patients Undergoing Percutaneous Coronary Intervention for Acute Coronary Syndrome

BACKGROUND

 A strong association between on-thienopyridine platelet reactivity (PR) and the risk of both thrombotic and bleeding events in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI) has been demonstrated. However, no study has analyzed the relationship between on-ticagrelor PR and clinical outcome in this clinical setting.

OBJECTIVES

 We aimed to investigate the relationship between on-ticagrelor PR, assessed by the vasodilator-stimulated phosphoprotein (VASP) index, and clinical outcome in patients with ACS undergoing PCI.

METHODS

 We performed a prospective, multicenter, observational study of patients undergoing PCI for ACS. PR was measured using the VASP index following ticagrelor loading dose. The primary study endpoint was the rate of Bleeding Academic Research Consortium (BARC) type ≥2 at 1 year. The key secondary endpoint was the rate of major adverse cardiovascular events (MACE) defined as the composite of cardiovascular death, myocardial infarction, stroke, and urgent revascularization.

RESULTS

 We included 570 ACS patients, among whom 33.9% had ST-elevation myocardial infarction. BARC type ≥2 bleeding occurred in 10.9% and MACE in 13.8%. PR was not associated with BARC ≥2 or with MACE (p = 0.12 and p = 0.56, respectively). No relationship between PR and outcomes was observed, neither when PR was analyzed quantitatively nor when it was analyzed qualitatively (low on-treatment PR [LTPR] vs. no LTPR).

CONCLUSION

 On-ticagrelor PR measured by the VASP was not associated with bleeding or thrombotic events in ACS patients undergoing PCI. PR measured by the VASP should not be used as a surrogate endpoint in studies on ticagrelor.

Tissue damage from neutrophil-induced oxidative stress in COVID-19

In this Comment article, Becker and colleagues consider how the excessive release of reactive oxygen species by neutrophils may perpetuate red blood cell dysfunction, thrombosis and tissue damage in severe cases of COVID-19.

Heparin-induced thrombocytopenia in COVID-19 patients with severe acute respiratory distress syndrome requiring extracorporeal membrane oxygenation: two case reports

Veno-venous (VV) extracorporeal membrane oxygenation (ECMO) is increasingly used in Coronavirus disease-19 (COVID-19) patients with the most severe forms of acute respiratory distress syndrome (ARDS). Its use is associated with a significant hemostatic challenge, especially in COVID- 19 patients who have been demonstrated to otherwise present a COVID-19-associated coagulopathy. The systematic use of unfractionated heparin therapy to prevent circuit thrombosis is warranted during ECMO support. The clinical presentation and management of heparin-induced thrombocytopenia, which is a rare but life-threatening complication of heparin therapy, has not been described in those patients yet. We report herein two cases of laboratory-confirmed HIT in COVID-19 patients with severe ARDS admitted to our intensive care unit for VV-ECMO support and the successful use of argatroban as an alternative therapy. We also provide a brief literature review of best evidence for managing such patients. The diagnosis and management of HIT is particularly challenging in COVID-19 patients receiving ECMO support. An increased awareness is warranted in those patients who already present a procoagulant state leading to higher rates of thrombotic events which can confuse the issues. Argatroban seems to be an appropriate and safe therapeutic option in COVID-19 patients with HIT while on VV-ECMO.

Management of cancer-related thrombosis in the era of direct oral anticoagulants: A comprehensive review of the 2019 ITAC-CME clinical practice guidelines. On behalf of the Groupe Francophone Thrombose et Cancer (GFTC)

Venous thromboembolism (VTE) is a common disease complication in cancer patients and the second cause of death after cancer progression. VTE management and prophylaxis are critical in cancer patients, but effective therapy can be challenging because these patients are at higher risk of VTE recurrence and bleeding under anticoagulant treatment. Numerous published studies report inconsistent implementation of existing evidence-based clinical practice guidelines (CPG), including underutilization of thromboprophylaxis, and wide variability in clinical practice patterns across different countries and various practitioners. This review aims to summarize the 2019 ITAC-CME evidence-based CPGs for treatment and prophylaxis of cancer-related VTE, which include recommendations on the use of direct oral anticoagulants specifically in cancer patients. The guidelines underscore the gravity of developing VTE in cancer and recommend the best approaches for treating and preventing cancer-associated VTE, while minimizing unnecessary or over-treatment. Greater adherence to the 2019 ITAC guidelines could substantially decrease the burden of VTE and improve survival of cancer patients.

Platelet reactivity inhibition following ticagrelor loading dose in patients undergoing percutaneous coronary intervention for acute coronary syndrome

BACKGROUND

Ticagrelor induces more potent platelet reactivity (PR) inhibition with reduced interindividual variability compared to clopidogrel. Although on-clopidogrel PR was shown to correlate with ischemia and bleeding events, no study has investigated the relationship between on-ticagrelor PR and outcome.

OBJECTIVES

We aimed to evaluate the relationship between on-ticagrelor PR, assessed by the vasodilator-stimulated phosphoprotein index (VASP), and thrombotic and bleeding events in patients with acute coronary syndrome (ACS) treated by percutaneous coronary intervention (PCI).

METHODS

We performed a prospective, multicenter observational study on patients treated with PCI for ACS. The VASP index was used to assess PR after ticagrelor loading dose (LD). The primary endpoint was the link between major adverse cardiovascular events (MACE) and PR.

RESULTS

Among the 530 patients with ACS included, 183 (34.5%) were admitted for ST elevation myocardial infarction. We observed high potency and limited interindividual variability after the ticagrelor LD (VASP 19.1% ± 16.6%). At 1 month, 21 (3.8%) MACE and 29 (5.5%) bleedings ≥ 2 according to the Bleedings Academic Research Consortium (BARC) scale were recorded. Neither MACE nor bleeding was associated with PR (P = .34 and P = .78, respectively). However, there was a strong association between PR and the occurrence of definite acute stent thrombosis (P = .03). Platelet reactivity was the only factor associated with acute definite stent thrombosis.

CONCLUSION

In patients receiving a ticagrelor LD while undergoing PCI for ACS, PR using the VASP did not predict MACE or bleeding, but it was significantly associated with the occurrence of definite acute stent thrombosis.

[Treatment of cancer associated thrombosis: Which role for direct oral anticoagulants in 2018?]

Low molecular weight heparin (LMWH) for at least 3-6 months is the current standard of care for the treatment of cancer associated venous thromboembolism (VTE). Anticoagulation should be continued as long as the cancer is active. In recent years, several direct-acting oral anticoagulants (DOACs) have been approved for the treatment of VTE in the general population. These drugs have progressively emerged as attractive alternatives with the potential to overcome the limitations of LMWH. Due to the lack of high quality prospective data, DOACs are currently not recommended for the treatment of cancer associated VTE yet. Indeed, evidence supporting the use of DOACs in this specific population remains limited, and concerns have been raised about their safety and efficacy in this setting. However, a pattern of increased use of DOACs has been observed in the cancer population. Meta-analyses of Phase III trials of DOACs in VTE as well as analysis of large health care claims databases and non-controlled retrospective studies suggest that DOACs might have similar effectiveness and safety to LMWH for the management of cancer associated VTE. Results from 2 randomized clinical trial (RCT), HOKUSAI-Cancer and SELECT-D, were recently released. Based on a meta-analysis of these 2 RCTs, compared to LMWH, DOACs had lower 6 month recurrent VTE but higher major bleeding. Thus, DOACs should be used with caution in cancer patients and a careful evaluation of the risks and benefits for individual patients is warranted. Ongoing studies will provide much needed evidence to guide clinical care.

[Venous thromboembolism and pancreatic cancer]

Pancreatic cancer (PC) is a devastating malignancy with an overall 5-year survival of 8% for all stages combined. Most of the PC patients diagnosed have an advanced disease (40%) or metastatic stage (40%), which eliminates surgery as a potentially curative treatment. The disease course is often complicated by venous thromboembolism (VTE) events, which per se account for significant morbidity and mortality, with significantly worsen survival. PC is associated with the highest risk of VTE among all cancer patients. We review the literature data to address the incidence and clinical outcomes of VTE in PC patients. VTE incidence varies from 5 to 41% according to epidemiological studies and is as high as 57% in postmortem series. Since 2013, international clinical practice guidelines recommend primary thromboprophylaxis with a grade 1B level of evidence as an adjuvant therapy in advanced PC. A recent meta-analysis of randomized controlled trials investigating the benefit and risk of low-molecular-weight heparins (LMWH) in ambulatory advanced PC patients under chemotherapy showed that the incidence of VTE was 2.1% in patients treated with LMWH and 11.2% in controls (risk ratio, 0.18; 95% CI, 0.083-0.39; P<0.0001). In conclusion, improved earlier diagnosis and effective management of VTE, a frequent and life-threatening complication in PC, is warranted to improve PC patient outcomes.

[New international guidelines for curative treatment and prophylaxis for venous thromboembolism (VTE) in cancer patients and the dedicated smartphone application]

Venous thromboembolism (VTE) is a frequent and serious complication in cancer patients, and the second leading cause of death in this setting. Cancer patients are also more likely to present recurrent VTE and major bleeding while taking anticoagulants. Management of VTE in these patients is always challenging and remains suboptimal worldwide. In 2013, the International Initiative on Thrombosis and Cancer (ITAC-CME) released international guidelines for the treatment and prophylaxis of VTE and central venous catheter-associated thrombosis, based on a systematic review of the literature ranked according to the Grading of Recommendations Assessment, Development, and Evaluation scale. An update of these ITAC-CME consensus guidelines, including the use of direct oral anticoagulants, was recently published. In this review, we summarize these updated guidelines. Better adherence to the international guidelines, involving an adequate educational and active implementation strategies, will substantially decrease the burden of VTE and allow to increase survival in cancer patients.

Assessment of platelet function on the routine coagulation analyzer Sysmex CS-2000i

BACKGROUND

Light transmission aggregometry (LTA) is considered as the gold standard for testing platelet function in the setting of both platelet disorders suspicion and response to antiplatelet therapy evaluation. LTA requires however specialized equipment, substantial blood sample volumes, is technically challenging and time-consuming.

AIM

To evaluate an automated platelet aggregation method performed on a routine coagulation analyzer Sysmex CS-2000i.

METHODS

46 patients presenting a bleeding syndrome and 62 patients with acute coronary syndrome receiving dual antiplatelet therapy were studied in total. Platelet aggregations were performed on CS-2000i equipped with a dedicated software and on APACT-4004 (Elitech, France) as the reference instrument. Aggregation was measured by monitoring the changes in light absorbance occurring in response to ADP 2.5, 5 and 10µM, collagen 3.3 µg/mL, epinephrin 10µM, ristocetin 1.25 mg/mL and arachidonic acid 0.5 mg/mL in platelet rich plasma (PRP). PRP were tested simultaneously on both CS-2000i and APACT-4004 devices. Platelet stirred speed were 800 rpm for both instruments.

RESULTS

Significant correlations were observed between CS-2000i and LTA after all stimulations (p< 0.001). Patients presenting a bleeding syndrome had similar aggregation profiles with both methods. A single patient presented a severe platelet disorder (Glanzmann Thrombasthenia) and its PRP showed defective aggregation in response to all agonists except ristocetin with both instruments. Finally, the inter-agreement rates for CS-2000i and APACT-4004 to detect low responders to thienopyridines or aspirine were strong (weighted kappa> 0.70).

CONCLUSION

Platelet aggregation on the routine coagulation analyzer CS-2000i is an easily accessible, handy, reliable, standardized, and rapid tool to assess platelet function which allows to skirt most of the LTA limitations.

Major bleeding complications in patients treated with direct oral anticoagulants: One-year observational study in a Paris Hospital

Direct oral anticoagulants (DAOC) are indicated for the treatment of venous thromboembolism and the prevention of stroke or systemic embolism in patients with non-valvular atrial fibrillation. Given their advantages and friendly use for patient, the prescription of long term DOAC therapy has rapidly increased both as first line treatment while initiating anticoagulation and as a substitute to vitamins K antagonist (VKA) in poorly controlled patients. However, DOAC therapy can also be associated with significant bleeding complications, and in the absence of specific antidote at disposal, treatment of serious hemorrhagic complications under DOAC remains complex. We report and discuss herein five cases of major hemorrhagic complications under DOAC, which were reported to the pharmacological surveillance department over one year at Saint-Louis University Hospital (Paris, France). We further discuss the need for careful assessment of the risk/benefit ratio at time of starting DOAC therapy in daily clinical practice.

PO-34 - Optimal doses of tinzaparin to reduce both cancer-associated thrombosis and tumor growth in a mouse model of ectopic pancreatic syngeneic tumor

INTRODUCTION

In clinical studies, thromboprophylaxis with low-molecular-weight heparins (LMWHs) has been demonstrated to reduce the risk of venous thromboembolism and to improve outcomes in cancer patients. Moreover, preclinical models have previously suggested that LMWHs may also offer additional benefits through direct antitumor properties. However, the optimal doses of LMWHs that may prevent both cancer-related thrombosis and tumor development are yet unknown.

AIM

The goal of this study was to determine the optimal doses of tinzaparin that may prevent both cancer-related thrombosis and tumor development in a syngeneic ectopic model of pancreatic cancer.

MATERIALS AND METHODS

The optimal doses of tinzaparin to generate a plasma anti-Xa activity >0.2IU/mL were determined in vivo following injection into wild type mice.The syngeneic ectopic model of cancer was induced in wild-type mice using the mouse pancreatic cancer cell line Panc02. Mice were injected daily with 200, 300IU/kg or 400IU/kg, or placebo from day 8 to 25 following tumor induction. Kinetics of thrombus formation and fibrin generation were determined in real time by digital real time intravital microscopy in mice bearing a tumor treated with tinzaparin or placebo. The growth of the tumor and the bleeding times were measured and compared in the different groups of mice.

RESULTS

Plasma anti-Xa levels <0.2IU/mL were observed with tinzaparin doses ranging from 0 to 150IU/kg, whereas plasma anti-Xa activities >0.2IU/mL were obtained with >200IU/kg tinzaparin doses. At day 25 following tumor induction, the kinetics of thrombosis were not affected in mice treated with daily 200IU/kg tinzaparin compared to controls whereas it was strongly affected in mice treated with daily 300 and 400IU/kg tinzaparin. Interestingly, a significant decrease in tumor growth was observed in mice treated with 200, 300 and 400IU/kg tinzaparin in comparison to controls, with no significant difference between these groups. Bleeding times were similar to control mice in mice treated with 200IU/kg tinzaparin, but significantly increased in mice treated with 300IU/kg and 400IU/kg tinzaparin.

CONCLUSIONS

At the dose of 200IU/kg, tinzaparin treatment significantly inhibits tumor growth but did not affect the thrombotic phenotype in mice developing a cancer. When 300 and 400IU/kg dose are used, tinzaparin treatment decreases both cancer-related thrombotic phenotype and tumor growth, but at the price of a significant increase in the bleeding time.

[Antiphospholipids antibodies and hemodialysis: a frequent association linked to arteriovenous fistula thrombosis]

Antiphospholipid antibodies (APL) are a heterogeneous family of auto-antibodies that recognize phospholipoproteins bound antigenic epitopes. APL prevalence in patients on chronic hemodialysis ranges from 11 to 37% in the literature. The association of APL with hemodialysis vascular access (VA) thrombosis has already been reported in small studies. In this single center and retrospective study, we defined the APL prevalence and APL risk factors in a large cohort of 192 hemodialysis patients. The association between history of VA thrombosis and APL presence was also analyzed. At least one type of APL was found in 38 patients (19.8%) of which 74% (n=28) had only lupus anticoagulant. Median age of APL positive patients was 68.1years vs. 71.3years in APL negative patients (P=0.02). Smoking history was associated with APL presence: 35.5% of APL positive patients had a smoking history vs only 18.3% of APL negative patients (P=0.04). The multivariate analysis showed an association between the history of VA thrombosis and patient age (HR [IC 95%]=1.04 [1.02-1.06]; P=0.001) or APL presence (HR [IC 95%]=3.03 [1.69-4.42]; P<10(-3)). In conclusion, the prevalence of APL in hemodialysis patients remains high despite hemodialysis techniques improvement: hemodiafiltration, biocompatibility improvements, ultrapure dialysis water. We report that a younger age and past history of smoking are associated with an increased risk of APL presence. The presence of APL, especially lupus anticoagulant, is associated to VA thrombosis in hemodialysis patients.

Ticagrelor versus prasugrel in diabetic patients with an acute coronary syndrome. A pharmacodynamic randomised study

Optimal P2Y12 receptor blockade is critical to prevent ischaemic recurrence in patients undergoing percutaneous coronary intervention (PCI). We aimed to compare the level of platelet reactivity (PR) inhibition achieved by prasugrel and ticagrelor loading dose (LD) in diabetic acute coronary syndrome (ACS) patients undergoing PCI. We performed a single-center prospective open-label randomised trial. Patients with diabetes mellitus undergoing PCI for an ACS were randomised to receive prasugrel 60 mg or ticagrelor 180 mg. The primary endpoint of the study was the level of platelet reactivity (PR) assessed between 6 and 18 hours post-LD using the VASP index. We randomised 100 diabetic patients undergoing PCI for an ACS. No difference was observed in baseline characteristics between the two groups. In particular, the rate of patient receiving insulin therapy was identical (25 vs 28.6%; p =0.7). Ticagrelor achieved a significantly lower PR compared to prasugrel loading dose (17.3 ± 14.2 vs 27.7 ± 23.3%; p=0.009). In addition the rate of high on-treatment platelet reactivity, defined by a VASP ≥50%, tend to be lower in the ticagrelor group although the difference did not reach statistical significance (6 vs 16%; p=0.2). The rate of low on treatment PR was identical (60 vs 54%; p=0.8). The present study demonstrates that ticagrelor LD is superior to prasugrel LD to reduce PR in ACS patients with diabetes mellitus. Whether the higher potency of ticagrelor could translate into a clinical benefit should be investigated.

Adrenergic receptor polymorphisms and platelet reactivity after treatment with dual antiplatelet therapy with aspirin and clopidogrel in acute coronary syndrome

Platelet response to clopidogrel shows inter-individual variability that is partially explained by genetic polymorphisms. This variability affects clinical outcome when clopidogrel is administered in patients with acute coronary syndrome (ACS). Catecholamines, released during ACS, contribute to platelet aggregation through platelet alpha2A-(alpha2A-AR) and beta2-adrenergic receptor (beta2-AR) stimulation. It was the objective of this study to assess the potential influence of alpha2A-AR and beta2-AR gene polymorphisms on platelet reactivity after dual antiplatelet therapy with aspirin and clopidogrel in ACS. We screened 641 ACS patients for 6.3/6.7 kb alpha2A-AR polymorphism, and for Arg16Gly and Gln27Glu beta2-AR polymorphism. After 600 mg clopidogrel, we assessed ADP 10 micromol-induced platelet aggregation (ADP-Ag) and vasoactive stimulated phosphoprotein (VASP). All single nucleotide polymorphisms were in Hardy-Weinberg equilibrium. A slight though negligible association was found between 6.3 kb allele of alpha2A-AR with platelet reactivity ADP-Ag induced (beta: -2.91 [-5.68;-0.14], p=0.04). A borderline not significant reduction in PRI VASP was observed in 6.3 kb alpha2A-AR carriers (beta: -3.81 [-0.09;7.72], p=0.06). No significant effect on platelet parameters was observed for the other tested polymorphisms. Common alpha2A- and beta2-adrenergic receptor polymorphisms do not show any major impact on residual platelet reactivity in non-ST-elevation ACS when a dual antiplatelet therapy with 250 mg aspirin and 600 mg clopidogrel is administered.

[Platelet function after a high dose bolus of tirofiban immediately after coronary angioplasty]

In the TARGET trial, the lower incidence of cardiac events at one month with abciximab compared with tirofiban was attributed to a lack of efficacy in the first hour because of suboptimal dosage. The object of this study was to confirm that high dose tirofibal is associated with over 90% platelet inhibition during the first hour and to analyse the effect of this new dosage on platelet activation. Thirty-three patients treated with clopidogrel and aspirin for an acute coronary syndrome without ST elevation were given before angioplasty a bolus of 25 microg/Kg of tirofiban injected in 3 minutes, followed by an infusion of 0.15 microg/kg/min. Blood samples were taken before the treatment (TO) and at the 45th minute (T1) to measure platelet aggregation induced by ADP, the expression of P-selection, the quantification of circulating monocyte-platelet aggregates and the phospholyration of VASP protein. The results showed that all patients had over 90% (100%) inhibition of platelet aggregation at T1. The expression of P-selection was significantly reduced (T0: 0.195 +/- 0.057 MFI; T1: 0.186 +/- 0.055 MFI, p = 0.03). There was no significant difference in the number of monocyte-platelet aggregates or in the phosphorylation of VASP. In conclusion, a bolus of 25 microg/Kg/3 min of tirofiban provides over 90% inhibition of platelet aggregation in the first hour. The initial platelet proactivator effect at this dosage was shown to have disappeared with an inhibition of platelet activation.

[Beneficial effect of a loading dose of 600 mg of clopidogrel on platelet parameters in patients admitted for acute coronary syndrome]

INTRODUCTION

Despite the beneficial effect of an aspirin-clopidogrel combination in acute coronary syndrome, the incidence of ischaemic recurrences remains significant and very probably implicates a variability in the response to anti-platelet agents.

OBJECTIVE

We sought to demonstrate the evidence for a beneficial effect, in terms of anti-platelet effect, of a higher loading dose of 600 mg of clopidogrel compared to the usual 300 mg in patients admitted to our centre with acute coronary syndrome.

MATERIALS AND METHODS

Platelet reactivity was evaluated with the ADP 10_mol test and the degree of platelet activation by the expression of P-selectin. 178 consecutive patients admitted for acute coronary syndrome received 250 mg of intravenous aspirin together with either a loading dose of 300 mg of clopidogrel (n = 104) or 600 mg (n = 74) administered 12 to 24 hours prior to coronary angiography.

RESULTS

The patients who received 600 mg of clopidogrel had an average aggregation intensity to ADP and a rate of platelet high reactivity post treatment that was significantly lower [48+20 vs 58+18, p = 0.0011 and 11 patients (15%) vs 26 patients (25%), p = 0.0003 respectively]. The degree of platelet activation evaluated with P-selectin was significantly lower in patients receiving 600mg [0.33 + 0.17 vs 0.50+0.29, p < 0.001].

CONCLUSION

Our study provides evidence for a beneficial effect of a loading dose of 600mg of clopidogrel compared to the usual 300 mg in terms of platelet reactivity and platelet activation post treatment.

Evolution of Thrombin Formation and Fibrinolysis Markers, Including Thrombin-Activatable Fibrinolysis Inhibitor, during Severe Meningococcemia

A 17-year-old girl presented with Neisseria meningitidis sepsis, with evidence of disseminated intravascular coagulation. Substitution therapy with both antithrombin and protein C concentrates was initiated, leading to clinical and biological improvement. Sequential dosages were performed for biological markers including thrombin-activatable fibrinolysis inhibitor (TAFI). Substitution therapy with both antithrombin and protein C concentrates led to a clinical and biological improvement. Biological markers showed a decrease in thrombin generation and in plasminogen activator inhibitor 1 (PAI-1) and a return of TAFI to a normal value. Discontinuation of substitutive treatment was marked by a clinical relapse at 24 h, with thrombin generation and increase in PAI-1, while TAFI remained unchanged. This report shows the evolution of hemostasis markers during septic shock and provides new data concerning the effects of a substitutive therapy.

Fine mapping of quantitative trait nucleotides underlying thrombin-activatable fibrinolysis inhibitor antigen levels by a transethnic study

Recent studies revisiting the association between plasma thrombin-activatable fibrinolysis inhibitor (TAFI) Ag levels and polymorphisms of the CPB2 gene (coding for TAFI) suggested that TAFI Ag levels were influenced by 2 major quantitative trait nucleotides (QTNs) in European whites. However, the strong linkage disequilibrium (LD) between CPB2 polymorphisms in European whites did not allow one to distinguish which polymorphisms could be the putative QTNs. To get a better insight into the identification of QTNs, a transethnic haplotype analysis contrasting 2 populations of African and European subjects was performed using 13 CPB2 polymorphisms. Results of the haplotype analyses suggested that 3 QTNs had independent effects and explained about 15% of the TAFI variability, consistently in the 2 populations. The lower LD observed in the African population enabled us to identify the 1583T>A SNP located in 3'UTR as one of these QTNs, whereas the -2599C>G and -2345--2344insG SNPs located in the 5' region might be the 2 other QTNs. A phylogenetic study suggested that these 3 polymorphisms occurred before the period of migration "out of Africa." Although this transethnic comparison contributed to better map the putative CPB2 QTNs, further studies are required to clarify the role of the promoter region.

TGF-β1 Released from Activated Platelets Can Induce TNF-Stimulated Human Brain Endothelium Apoptosis: A New Mechanism for Microvascular Lesion during Cerebral Malaria

Platelets have recently been shown to accumulate in brain microvessels of patients with cerebral malaria and to modulate the binding of Plasmodium falciparum-infected red cells to human brain endothelium in vitro. In the present study we used a platelet-endothelial cell coculture model to investigate the mechanisms by which platelets modify the function of human brain microvascular endothelial cells (HBEC). Platelets were found to have a proapoptotic effect on TNF-activated HBEC, and this was contact-dependent, as inhibiting platelet binding prevented endothelial cell killing. We also showed that the supernatants of thrombin-activated platelets killed TNF-stimulated HBEC and that TGF-beta1 was the main molecule involved in endothelial cell death, because its inhibition completely abrogated the activated-platelet supernatant effect. Our data illustrate another aspect of the duality of TGF-beta1 in malaria and may provide new insights into the pathogenesis of cerebral malaria.

Quantification of thrombin activatable fibrinolysis inhibitor (TAFI) gene polymorphism effects on plasma levels of TAFI measured with assays insensitive to isoform-dependent artefact

Reports have reappraised the genotype-dependent variation of Thrombin Activatable Fibrinolysis Inhibitor (TAFI), demonstrating that, in some enzyme-linked immunosorbent assays (ELISA), decreased antibody reactivity towards the TAFI 325 Ile isoform led to erroneous TAFI levels. Assays free of this artefact are required to evaluate the contribution of the TAFI gene polymorphisms to TAFI level variability. TAFI levels were measured in 209 individuals with both immunological and functional assays. Each assay was characterized, in particular for its reactivity towards the 325 Thr and Ile isoforms. Two ELISAs were found to have a lower reactivity towards the Ile isoform, leading to an overestimate of the magnitude of variation between two different genotypes. In contrast, one ELISA, as well as functional assays, was found to be free of genotype-dependent artefact constituting a reliable method to detect true quantitative variations of TAFI levels. Using these reliable methods, univariate and haplotype analyses revealed that TAFI gene polymorphisms explain 25% of TAFI level variability. This effect seems to be the consequence of the joint independent action of two polymorphisms, one in the 5' (G-1102T) and the other in the 3' region (T+1583A) of the TAFI gene.

Substances produites par le tissu adipeux, obésité et risque vasculaire

Obesity is associated with increased risk of cardiovascular morbidity. Biologically active molecules produced by adipose tissue constitute a critical link between obesity and cardiovascular complications. Adipose tissue has recently been recognized to be an important endocrine organ that controls energy metabolism. It also secretes adipocytokines, which can modify vascular responses, and antifibrinolytics, including plasminogen activator inhibitor 1, which favors fibrin accumulation, and proinflammatory cytokines, which facilitate the inflammatory response. Here we review new advances in our understanding of the mechanisms linking the endocrine activity of adipose tissue to vascular risk.

Weak and non-independent association between plasma TAFI antigen levels and the insulin resistance syndrome

Increased plasma thrombin-activatable fibrinolysis inhibitor (TAFI) levels were recently shown to be a part of the insulin resistance syndrome. We investigated the relationship between plasma TAFI antigen levels and insulin resistance markers and compared these results with those obtained for PAI-1 and fibrinogen which are known to be closely related to insulin resistance syndrome and fat mass, respectively. Eighty-nine obese females had 1.3-, 1.2-, and 3-fold higher circulating TAFI, fibrinogen and PAI-1, respectively, compared with 64 lean females. Univariate analysis showed that the significance level for association between TAFI or fibrinogen concentrations and insulin resistance markers was lower than the significance level for association between PAI-1 and insulin resistance markers. Nevertheless, TAFI, fibrinogen, and PAI-1 plasma levels were significantly associated to each other. In linear stepwise ascendant analysis, insulin resistance markers accounted for 50% of the interindividual variability of plasma PAI-1 and only for 10% of plasma TAFI and 13% of fibrinogen variability. The contribution of insulin resistance markers to plasma TAFI antigen levels variability disappeared when PAI-1 or fibrinogen was entered in the statistical model. TAFI mRNA was detected in the liver but not in adipose tissue and endothelial cells. No TAFI mRNA was detected in normal or atherosclerotic vessels either. These results suggest that elevated TAFI antigen levels found in obese subjects are not independently associated with the metabolic markers of the insulin resistance syndrome. Increased plasma TAFI antigen levels in obesity might reflect a specific pathway of regulation at the liver level.

Reconstruction in inclined planes of curved computer generated holograms

The determination of the complex amplitude in the hologram is one major step in the realization of computer generated holograms. Usually the input distribution is assumed to be in a plane parallel to the hologram plane. However, sometimes a more flexible geometry is of interest. Here, in particular an arbitrarily shaped computer generated hologram of a plane input distribution is considered. The calculation of the complex amplitude in the hologram mainly consists of a Fourier transformation and a nonlinear coordinate transformation. The feasibility of this procedure is demonstrated by optical reconstructions of cylindrically shaped computer generated holograms in arbitrarily oriented planes.

Large objects reconstructed from computer-generated holograms

In digital holography the first step is the determination of the complex amplitude in the hologram. Large objects can be synthesized from tilted planar segments. In the calculation step, configurations of inclined object and inclined hologram plane are considered. The Fresnel transformation is generalized, and its implementation is discussed. Optical reconstructions show the feasibility.

Computer-generated holograms of 3-D objects composed of tilted planar segments

The Fresnel diffraction of tilted planar objects is determined. It can be calculated by a Fourier transformation, a coordinate transformation, and a subsequent multiplication by a quadratic phase. Images of 3-D objects are composed by superimposing several planar segments. The resultant complex amplitude is coded and stored in a computer-generated hologram. Optical reconstructions of planar segments nearly parallel to the optical axis are demonstrated.