Intravenous thrombolysis for acute ischaemic stroke in patients on direct oral anticoagulants.

BACKGROUND AND PURPOSE: Whereas intravenous thrombolysis (IVT) is allowed for acute ischaemic stroke in patients on vitamin K antagonists with international normalized ratio ≤1.7, there are no similar recommendations for patients on direct oral anticoagulants (DOACs), notably due to the lack of coagulation tests to assess the therapeutic effects. Although the literature is scarce, consisting of small case series and retrospective studies, considering the frequency of this situation the French Vascular Neurology Society and the French Study Group on Haemostasis and Thrombosis have worked on a joint position paper to provide a practical position regarding the emergency management of ischaemic stroke in patients on DOACs. METHOD: Based on a review of the literature, the authors wrote a first text that was submitted to a broad panel of members from the two societies. The text was then amended by the authors to address experts' comments and to reach a consensus. RESULTS: In patients with normal renal function and who stopped the DOAC for at least 48 h, the management should not differ from that in patients without oral anticoagulant. In patients who are still on DOACs, mechanical thrombectomy is encouraged preferentially when applicable in first line. Otherwise, when specific tests are available, values <50 ng/ml indicate that IVT is allowed. In the absence of specific tests, standard tests (thrombin time, prothrombin time and activated partial thromboplastin time) can be used for dabigatran and rivaroxaban, although interpretation of these tests may be less reliable. In some patients on dabigatran, idarucizumab may be used before IVT. CONCLUSIONS: In this expert opinion paper, it is suggested that IVT can be performed in patients selected according to the time elapsed since the drug was last taken, renal function, type of hospital where the patient is admitted and plasma concentration of DOAC.

Compliance with evidence-based clinical management guidelines in bleeding trauma patients.

BACKGROUND: In 2007, the multidisciplinary European Task Force for Advanced Bleeding Care in Trauma published guidelines for the management of the bleeding trauma patient. The present study aimed to assess compliance with the European guidelines during the first 24 h in a level I trauma centre and to determine whether compliance impacts mortality. METHODS: This was a retrospective study of consecutive bleeding trauma patients referred to a university hospital in France between 2010 and 2014. A reference document was developed on the basis of the European guidelines to transform the guidelines pragmatically into 22 objectively measurable criteria. We measured per-patient and per-criterion compliance rates and assessed the impact of guideline compliance on mortality. RESULTS: A total of 121 bleeding trauma patients were included. The median (interquartile range) per-patient compliance rate was 75 (65-82)% and the per-criterion compliance rate 64 (57-81)%. Mortality rates were 18 and 32% at 24 h and 30 days, respectively. After adjusting for injury severity, per-patient compliance rates were associated with decreased mortality at 24 h (odds ratio per 10% increase in patient compliance score, 0.43; 95% confidence interval 0.26-0.71; P = 0.0001) and at 30 days (odds ratio per 10% increase in patient compliance score, 0.47; 95% confidence interval 0.31-0.72; P = 0.0004). CONCLUSIONS: We found that compliance with protocols based on European guidelines impacts trauma outcome, because patient compliance was associated with survival. Further work is needed to improve adherence to these guidelines, with ongoing monitoring to ensure best practice and optimal patient outcome.

Postpartum haemorrhage related early increase in D-dimers is inhibited by tranexamic acid: haemostasis parameters of a randomized controlled open labelled trial.

BACKGROUND: Beneficial effects of tranexamic acid (TA) have been established in surgery and trauma. In ongoing postpartum haemorrhage (PPH), a moderate reduction of blood loss was observed in a previously published randomized controlled trial. Analysis of haemostasis parameters obtained from samples collected as part of this study are presented. METHODS: Women with PPH >800 ml after vaginal delivery were assigned to receive either TA (4 g over 1 h, then 1 g per h over six h) (TA) or not (H). A non-haemorrhagic group (NH), <800 ml blood loss, was included as postpartum reference. At four time-points (enrolment, +30 min, +2 h, +6 h), haemostasis was assessed. Haemostasis assays were performed blinded to group allocation. Data were expressed as median [interquartiles] and compared with non-parametric tests. RESULTS: In H compared with NH group, D-dimers increase (3730 ng ml(-1) [2468-8493] vs 2649 [2667-4375]; P=0.0001) and fibrinogen and factor II decrease were observed at enrolment and became maximal 2 h later. When comparing TA to H patients, the increase in Plasmin-Antiplasmin-complexes at +30 min (486 ng ml(-1) [340-1116] vs 674 [548-1640]; P=0.03) and D-dimers at +2 h (3888 ng ml(-1) [2688-6172] vs 7495 [4400-15772]; P=0.0001) was blunted. TA had no effect on fibrinogen decrease. CONCLUSIONS: This study provides biological evidence of an early increase in D-dimers and plasmin-antiplasmin complexes associated with active post-partum haemorrhage and its attenuation by the early use of a clinically effective high dose of TA, opening the perspective of dose ranging studies to determinate the optimal dose and timing in this setting. CLINICAL TRIAL REGISTRATION: ISRCTN09968140.

Coagulation standards in healthy newborns and infants.

BACKGROUND: The range of normal values for coagulation factors in the healthy newborn was described 30 years ago but since then the reagents, automated systems, and dosing techniques have changed considerably. For 30 years, several authors have tried to update the standards and references in children using updated reagents but the newborn and infant population in these studies has been quite small, limiting the findings. The aim of this study was to establish the normal coagulation standards in healthy newborns. METHODS: We included all consecutive healthy newborns with pyloric stenosis presenting to our reference center over a period of 5 years. We calculated the reference ranges defined as mean±2 SD. Normality of distribution was checked graphically and by using the Shapiro-Wilk test. Correlations between two continuous variables were assessed using Spearman's rank coefficient correlation. Statistical testing was done at the two-tailed α-level of 0.05. Data were analyzed using the SAS software package, release 9.4 (SAS Institute, Cary, NC). RESULTS: We included 112 healthy newborns and infants. The median age was 35.5 days (15.0-88.0), median weight was 4062g (2855-6040), and 90.2% were boys. Activated partial thromboplastin time (aPTT) and prothrombin time (PT) were not correlated with age (P=0.92 and P=0.21, respectively) or with weight (P=0.16 and P=0.90, respectively). The reference range was 28.6-46.2 s for aPTT, 0.91-1.49 for aPTT ratio, and 71.3-110.6 s for PT. Regarding fibrinogen (n=24), the median was 2.2g/L (1.2-3.2); the median for factor II was 67.0U/dL (51.0-130.0; n=20), and 101.5U/dL for factor V (68.0-233.0; n=20). Regarding factor VIII, the median was 75.0U/dL (45.0-152.0; n=25), 49.0U/dL for factor IX (32.0-96.0; n=25) and 53.0U/dL (29.0-112.0) for factor XI (n=23). CONCLUSION: This study can help to establish standards for coagulation testing in this very specific population. Indeed, our study represents the largest newborn population in a recent investigation of PT and aPTT using updated reagents.

French lyophilized plasma versus fresh frozen plasma for the initial management of trauma-induced coagulopathy: a randomized open-label trial.

Essentials An immediate supply of plasma in case of trauma-induced coagulopathy is required. The Traucc trial compared French Lyophilised Plasma (FLyP) and Fresh Frozen Plasma (FFP). FLyP achieved higher fibrinogen concentrations compared with FFP. FLyP led to a more rapid coagulopathy improvement than FFP. SUMMARY: Background Guidelines recommend beginning hemostatic resuscitation immediately in trauma patients. We aimed to investigate if French lyophilized plasma (FLyP) was more effective than fresh frozen plasma (FFP) for the initial management of trauma-induced coagulopathy. Methods In an open-label, phase 3, randomized trial (NCT02750150), we enrolled adult trauma patients requiring an emergency pack of 4 plasma units within 6 h of injury. We randomly assigned patients to receive 4-FLyP units or 4-FFP units. The primary endpoint was fibrinogen concentration at 45 min after randomization. Secondary outcomes included time to transfusion, changes in hemostatic parameters at different time-points, blood product requirements and 30-day in-hospital mortality. Results Forty-eight patients were randomized (FLyP, n = 24; FFP, n = 24). FLyP reduced the time from randomization to transfusion of first plasma unit compared with FFP (median[IQR],14[5-30] vs. 77[64-90] min). FLyP achieved a higher fibrinogen concentration 45 min after randomization compared with FFP (baseline-adjusted mean difference, 0.29 g L-1 ; 95% confidence interval [CI], 0.08-0.49) and a greater improvement in prothrombin time ratio, factor V and factor II. The between-group differences in coagulation parameters remained significant at 6 h. FLyP reduced fibrinogen concentrate requirements. Thirty-day in-hospital mortality rate was 22% with FLyP and 29% with FFP. Conclusion FLyP led to a more rapid, pronounced and extended increase in fibrinogen concentrations and coagulopathy improvement compared with FFP in the initial management of trauma patients. FLyP represents an attractive option for trauma management, especially when facing logistical issues such as combat casualties or mass casualties related to terror attacks or disasters.

Drug-eluting stents: trading restenosis for thrombosis?

Within the last 6 years, it has been demonstrated that drug-eluting stents (DES) reduce significantly angiographic and clinical restenosis after percutaneous coronary interventions. These results are consistent across several clinical randomized controlled trials comparing these new devices with bare metallic stents (BMS), which themselves have already markedly improved the results obtained with balloon angioplasty in the early days of this method of myocardial revascularization. Nevertheless, some concerns have been raised regarding a delayed endothelialization of the coated prostheses leading to late stent thrombosis occurring mainly when antiplatelet therapy is discontinued in the follow-up. The most recent data show that, in comparison with BMS, there is a small excess of late (> 1 year) stent thrombosis but this is not associated with an increased risk of death or myocardial infarction or all cause mortality. These concerns do not outweigh the strong benefits of DES in preventing restenosis but require a number of measures concerning a longer dual antiplatelet treatment (than initially expected), to control patient treatment compliance and to provide a complete education of patients and physicians. Future devices dealing with the two issues (antiproliferative properties with rapid controlled endothelialization preventing thrombosis) would be the next major advance in this rapidly evolving field.

[Direct oral anticoagulant associated bleeding]. / Hémorragie survenant chez un patient traité par un anticoagulant oral direct.

Direct oral anticoagulants (DOAC) are recommended for stroke prevention in atrial fibrillation and for the treatment of venous thromboembolism. However, they are associated with hemorrhagic complications. Management of DOAC-induced bleeding remains challenging. Activated or non-activated prothrombin concentrates are proposed, although their efficacy to reverse DOAC is uncertain. Therapeutic options also include antidotes: idarucizumab, antidote for dabigatran, has been approved for use whereas andexanet alpha, antidote for anti-Xa agents, and aripazine, antidote for all DOAC, are under development. Other options include hemodialysis for the treatment of dabigatran-associated bleeding and administration of oral charcoal if recent DOAC ingestion. DOAC plasma concentration measurement is necessary to guide DOAC reversal. We propose an update on DOAC-associated bleeding, integrating the availability of dabigatran antidote and the critical place of DOAC concentration measurements.

Are there any additional mechanisms for haemolysis in HELLP syndrome?

HELLP syndrome is a microangiopathy that leads to severe maternal complications. The objective of this study was to identify any additional mechanisms that could have contributed to HELLP syndrome-induced haemolysis. This is a pilot, prospective and observational study that lasted 9months. All patients with HELLP syndrome treated at academic tertiary care women hospital accepted to participate. Sixteen patients were included. In ten patients (63%), schizocytes were detected following a blood smear test. Six patients (38%) were diagnosed with a partial expression deficiency of proteins regulating the complement system (CD 55 or CD 59). In nine patients (56%), an activation of the complement classical pathway was detected. In two patients (13%), an ADAMTS 13 activity below 30% was detected. Three patients (19%) were diagnosed with a folate deficiency and one (6%) with an antiphospholipid syndrome. All patients developed maternal or fetal morbidity including nine (56%) an acute kidney injury. All patients but one had at least one additional mechanism that could contribute to haemolysis, besides a simple physical injury. Larger studies should be promoted to understand haemolysis in HELLP syndrome.

Relevance of tissue factor in cardiovascular disease.

Overexpression and exposition of tissue factor (TF) in atherosclerotic plaques and/or arterial thrombi are critical events in atherothrombosis. TF, the receptor for factor VII (FVII) and activated factor VII (FVIIa), is the principal initiator of blood coagulation and induces thrombin generation leading to fibrin formation and platelet activation. TF also plays a major role in cell migration and angiogenesis. TF activity is downregulated by Tissue Factor Pathway Inhibitor (TFPI), a Kunitz-type inhibitor, which forms a neutralizing complex with TF, FVIIa and activated factor X. In physiological conditions, TF is absent from vascular cells which come into contact with flowing blood and is present as an inactive pool in fibroblasts and smooth muscle cells (SMC). In contrast, TF is widely expressed in atherosclerotic plaques and is found in macrophages, SMCs, and foam-cells and also in extracellular matrix and acellular lipid-rich core. TF expression is up-regulated by inflammatory cytokines and oxidized lipids. Plaque thrombogenicity is directly correlated to their TF content. After fibrous cap disruption, TF is exposed on plaque surface and triggers thrombus formation leading to arterial lumen occlusion and/or downstream embolization. In coronary and carotid plaques, TF content was found to be higher in plaques from symptomatic than asymptomatic patients. Soluble forms of TF and microparticles of monocyte and platelet origin, and bearing TF, constitute "blood-born TF". The contribution of this TF pool to arterial thrombosis is still under discussion. TF pathway is a target for new therapeutic agents that can decrease TF activity, such as active site-inactivated factor VIIa, recombinant TFPI and antibodies against TF or peptides interfering with TF-FVIIa complex activity.

[Prophylaxis of thromboembolic events during urologic surgery]. / Prévention de la maladie thromboembolique en chirurgie urologique.

Few scientific evidences are available in the literature, and the methodologic quality of the studies is often under average. Nevertheless, the conclusions are the following. Nephrectomy, renal transplantation, open surgery of the lower urinary tract and lumbar or pelvic lymph nodes dissection are at high risk for thromboembolic events. Other open or endoscopic urological procedures are at low risk. The laparoscopic approach doesn't change the risk associated with the procedure itself. Thromboprophylaxis is recommended in high-risk procedures. There was no evidence to recommend starting the prophylaxis before more than after the procedure. The use of low molecular weight heparin is recommended for prophylaxis. It can be associated with compressive stockings. It is recommended to treat for around seven days after the procedure. In case of cancer surgery, prophylaxis could be needed for four to six weeks.

Circulatory support devices: fundamental aspects and clinical management of bleeding and thrombosis.

Circulatory support devices are increasingly being used to overcome cardiac or respiratory failure. Long-term devices are used either as a 'bridge to transplant' to support patients who are unable to wait any longer for a heart transplant, or, more recently, as 'destination therapy' for older patients suffering from end-stage heart failure and who have contraindications to heart transplantation. Short-term support devices for high-risk percutaneous coronary intervention, or as a 'bridge for decision' for patients suffering from refractory cardiogenic shock, have also been developed. The clinical benefit of such assist devices has been demonstrated in several important studies, but, unfortunately, thrombotic and bleeding complications are two major clinical issues in patients requiring these devices. Overcoming these issues is of major importance to allow the safe and broad use of these devices, and to consider them as true alternatives to heart transplantation. The present review focuses on thrombotic and bleeding complications, and describes how the risk of thrombosis and bleeding may vary according to the clinical indication, but also according to the type of device. We describe the current knowledge of the mechanisms underlying the occurrence of these complications, provide some guidance for choosing the most appropriate anticoagulation regimen to prevent their occurrence for each type of device and indication, and provide some recommendations for the management of patients when the complication occurs.

Immunomodulatory effect of pentoxifylline during human allograft rejection: involvement of tumor necrosis factor-alpha and adhesion molecules.

BACKGROUND: Pentoxifylline (PTX), a methylxanthine phosphodiesterase inhibitor, is poorly active as an immunosuppressant but prevents the synthesis of proinflammatory cytokines. In a randomized double-blind study comparing PTX versus placebo in 140 patients receiving cadaveric kidney grafts under cyclosporine and prednisone, we have shown that PTX weakened the consequences of rejection on graft survival. To assess the mechanism underlying the beneficial effect recorded during this trial, we analyzed the impact of PTX on tumor necrosis factor (TNF-alpha) production and expression of cell adhesion molecules. METHODS: Plasma levels of TNF-alpha and its soluble receptors (sTNF-RI, sTNF-RII) and of soluble vascular cell adhesion molecule 1 (sVCAM-1) were monitored over the 6 months postgraft period when PTX or placebo were administered. Expression of VCAM-1 and intercellular cell adhesion molecule 1 was scored by immunohistochemical staining of biopsy specimens from patients who underwent rejection crisis. Lymphocyte subset composition was analyzed longitudinally during cytomegalovirus (CMV) infections. RESULTS: Plasma TNF-alpha levels were significantly reduced in the PTX-treated group over the 6 months of administration, and specifically during isolated rejection episodes and during CMV infections. Plasma levels of sTNFR-I, sTNFR-II, and sVCAM-1 did not differ between the two groups of patients, but a decrease in renal tubular VCAM-1 expression was observed in the PTX group. During CMV infections, CD8 lymphocytosis and expansion of CD57+ (CD28-) CD8+ T cells were similar in the two groups. CONCLUSION: The data collected during this double-blind study point to an immunomodulatory role of PTX, the beneficial effect on graft survival resulting from a restraining effect of the drug on the inflammatory conditions involved in acute graft rejection.

Pentoxifylline prevents upregulation of monocyte tissue factor in renal transplant recipients undergoing post-graft complications.

Pentoxifylline (PTX) has been demonstrated to improve graft survival in renal transplant recipients undergoing post graft complications. As activated monocytes are possible initiators of vascular damage through tissue factor (TF) expression, we evaluated the monocyte TF expression and endothelium activation markers in 140 consecutive patients receiving cadaveric kidney grafts, randomized in a double-blind study comparing PTX versus placebo. Monocyte TF expression and plasma von Willebrand factor, tissue plasminogen activator, thrombomodulin and tumor necrosis factor-alpha (TNF-alpha) levels were determined before transplantation and each month after. Additional samplings were realized in case of acute rejection. TF and TNF-alpha expression were significantly modified after graft. In patients with complications, PTX prevented the increase of TF expression at month one, and after rejection episodes. Endothelium activation markers were significantly modified after graft and in patients with complications but PTX had no significant effect on their plasma levels. These results suggest that the protective effect of PTX on graft survival could be related to the prevention of monocyte TF upregulation associated with complications.

Detection of monocyte tissue factor after endotoxin stimulation: comparison of one functional and three immunological methods.

Monocyte procoagulant activity is mainly due to tissue factor (TF) expression, but functional assays may not be sufficiently accurate in clinical use, making useful a determination of TF antigen level. The aim of this study was to compare the results of one functional and three immunological TF assays (ELISA, immunocytochemical staining on slides and flow immuno cytometric analysis), in normal monocytes, after standardized stimulation by endotoxin. TF expression was determined in blood mononuclear cells isolated by gradient centrifugation and cultured, with or without various concentrations of endotoxin. On lysed cells, TF activity was determined by amidolytic assay and TF antigen level was determined, after triton extraction, by ELISA (Imubind, American Diagnostica). Mouse monoclonal antibody against TF (4508, American Diagnostica) was used for 1) immunocytochemical (ICC) staining on cytocentrifuge slides (Avidine-Biotine-peroxidase-Complex revelation) and 2) flow cytometric analysis using indirect labeling (Fab'2 Fluoresceine Isothyocyanate revelation). The determination of TF activity and TF antigen by ELISA method were equally sensitive to low concentration of endotoxin (0.005 EU/ml) and well correlated in the presence of higher concentrations of endotoxin. ICC led to a qualitative detection with a similar sensitivity to endotoxin stimulation. Flow cytometric analysis was poorly sensitive to increasing stimulation of monocytes. Of note, the functional, ELISA and immunocytochemical assays for monocyte TF expression were sensitive to endotoxin concentrations as low as 0.005 EU/ml.

Monocyte tissue factor response is decreased in patients with hyperlipidemia.

Monocytes are potent regulators of blood coagulation through the expression of tissue factor (TF) on stimulation and of tissue factor pathway inhibitor (TFPI), a selective inhibitor of TF pathway. As hyperlipidemia can modify some monocyte functions, we compared the TF and TFPI expression by circulating monocytes and the plasma TFPI levels between 65 healthy normolipemic controls and 38 nontreated hyperlipemic patients. TF and TFPI relationships with plasma lipoproteins are also examined. TF and TFPI expression were evaluated in peripheral mononuclear cells after isolation from blood by density gradient centrifugation and after short culture with or without lipopolysaccharide (LPS). TF and TFPI activity and antigen were measured in mononuclear cell lysates using amidolytic assay and enzyme-linked immunosorbent assay, respectively. TFPI activity and antigen were measured in plasma using the same methods. Plasma factor VII (FVII) activity and antigen were also determined. LPS-stimulated monocyte TF activity and antigen were lower in hyperlipidemic patients than in controls (0.0001

[Peripheral arterial revascularization: which antithrombotic agents?]. / Revascularisations artérielles périphériques: quels antithrombotiques?

Thrombotic occlusion after vascular reconstructive surgery is a frequent complication, specially when low-flow arteries and arterial prostheses are involved. Heparin therapy is usually administered in acute arterial insufficiency, and also during the perioperative period, in order to limit thrombus formation or propagation at the surgical or the cross-clamp application sites. The overall benefit of antiplatelet agents, specially aspirin, during the pre, peri and postoperative periods has been clearly demonstrated for arterial prostheses, and is probably useful in venous bypasses. Aspirin therapy also prevents thrombotic complication in other vascular beds, and reduces long-term cardiovascular morbidity and mortality. Oral anticoagulation by vitamin K antagonists, alone or combined with aspirin is perhaps an appropriate choice in selected patients with high risk of graft thrombosis, but cannot be recommended for routine treatments because of an increased risk of hemorrhage.

[Cell therapy to treat heart failure]. / Thérapie cellulaire et insuffisance cardiaque.

INTRODUCTION: Systolic heart failure is mainly due to a decreased left ventricular systolic function after myocardial infarction. Despite significant improvements in medical management of heart failure, the prognostic remains poor, with a 5-years survival only of 30%. PURPOSE: Current treatments are only able to delay progression toward end-stage heart failure. Heart transplantation is accessible only for selected patients. Thus, in the context of post-myocardial infarction, cell therapy appears to be a new original technique, available for the majority of patients and potentially non-invasive. CONCLUSION: After promising results in experimental models, a phase I clinical trial has been conducted in France, showing the feasibility of intracardiac autologous skeletal myoblast implantation. Other studies in Europe and USA are currently testing a variety of cells and delivery systems. A phase II-trial will begin in France.

[Hormone replacement therapy and venous thromboembolism]. / Traitement substitutif de la ménopause et risque thrombotique veineux.

Venous thromboemboembolism is a multigenic and a multifactorial disease. Several genetic risk factors have been identified: antithrombin, protein C and protein S deficiencies, and molecular defects in factor V gene (factor V Leiden) or factor II gene (G 20210A transition). Retrospective and prospective studies have demonstrated that hormone replacement therapy (HRT) in women is associated with a 2-3-fold increase of venous thromboembolism events. To minimize this risk, it seems desirable to carefully evaluate the individual clinical risk factors. Prescribing HRT should clearly be avoided in women with previous thromboembolic events. In case of familial thrombophilia, HRT should probably be prescribed with caution. Recent data suggest that transdermal HRT would induce a lower increase in thrombotic risk, but additional studies are needed to determine whether they can be safely used in women at risk. In each case, the net balance of risk and benefit of HRT use must consider the potential beneficial health effects, the most evident being the relief of climacteric symptoms.