Malgré le bénéfice observé par de nouvelles thérapeutiques, le devenir des patients hospitalisés pour une insuffisance cardiaque aigue (ICA) reste sombre. Ce pronostic péjoratif est en partie influencé par la survenue fréquente d’événements thrombotiques qui sont à parfois directement à l’origine du décès des patients. Les mécanismes physiopathologiques de cette hypercoagulabilité pourraient être considérés comme des cibles thérapeutiques d’intérêt. L’objectif de ce travail est de démontrer qu’une défaillance des systèmes biologiques contrôlant la thrombose est impliquée dans la physiopathologie de l’ICA. Notre travail met en évidence la présence d’une hypercoagulabilité de ces patients qui se caractérise par une génération de thrombine exagérée pendant la phase aigüe de la décompensation cardiaque et qui se normalise ensuite à distance. Cette élévation de la génération de thrombine est la conséquence d’une augmentation du nombre de microparticules procoagulantes circulantes et d’une altération de l'activité d’un système naturel anticoagulant représenté par la voie de la protéine C / Acute heart failure (AHF) is a syndrome with an increasing prevalence and a high mortality whose management is challenging given the incomplete understanding of its pathophysiology. This doomed prognosis is partly influenced by thromboembolic events and is often the cause of death. The present study demonstrates a significant shift towards a prothrombotic biological profile at the acute phase of decompensated heart failure. Using a comprehensive exploration of the dynamics of thrombin generation and inhibition, we found an increased overall thrombin-generating capacity in AHF patients during hospital course. Both increased in circulating procoagulant microparticles and impairment in the downregulation of thrombin generation by the anticoagulant C protein pathway represent mechanisms contributing to this hypercoagulable state in AHF

Le potentiel de génération thrombine (TGP en anglais) est une nouvelle mesure qui permet de quantifier in vitro l'activité globale de la thrombine reflétant bien les mécanismes in vivo de la coagulation. Ce méthode de dosage est sensible aux déficits de facteurs de coagulation, à la prise d'anti-coagulants et à de nombreux troubles de la coagulation. Au moment où j'ai débuté ma thèse, seuls deux polymorphismes génétiques, tous les deux situés dans le gène F2 codant pour la prothrombine, étaient connus pour influencer la variabilité plasmatique du TGP. Mon projet de thèse avait pour objectifs d'identifier de nouveaux facteurs génétiques, mais également épigénétiques, pouvant influencer les taux plasmatiques de TGP. Dans une première partie, j'ai mené la toute première étude d'association génome-entier (GWAS pour Genome Wide Association Study en anglais) sur 3 biomarqueurs (temps de latence, quantité totale de thrombine produite et niveau maximal de thrombine produite) du TGP dans deux études françaises rassemblant 1267 sujets et j'ai répliqué les résultats les plus significatifs dans deux autres études françaises indépendantes de 1344 sujets. Cette stratégie a permis de mettre en évidence qu'un polymorphisme génétique du gène ORM1 était associé de manière robuste au temps de latence, biomarqueur caractérisant le temps nécessaire pour initier la coagulation après induction. Dans la seconde partie de ma thèse, en suivant une stratégie similaire mais cette fois-ci en étudiant non plus des polymorphismes génétiques mais des marques de méthylation d'ADN, j'ai recherché si des niveaux de méthylation de site CpG, mesurés à partir d'ADN sanguin et couvrant l'ensemble du génome, pouvaient être associés à la variabilité des 3 mêmes biomarqueurs de TGP. Malheureusement, à partir de deux échantillons mis à ma disposition et rassemblant 425 sujets, je n'ai pas pu mettre en évidence d'association robuste entre des marques de méthylation sanguine et la génération trombine. / Thrombin Generation Potential (TGP) is a promising in vitro measurement that allows quantifying thrombin activity, in a close way to what happens in vivo. It is sensitive to coagulation factors deficiencies, anticoagulant proteins and is associated to thrombotic disorders. There exists two polymorphisms located in the F2 (prothrombin) gene known to influence TGP levels, and altogether they explain 11.3% of the TGP inter-individual variability. With the aims of identifying novel genetic and epigenetic factors that influence TGP variability, I have performed two different studies in the present work. First, I conducted the first genome-wide association study for the three TGP biomarkers (ETP, Peak and Lagtime) using imputation data from two French studies. The most significant single nucleotide polymorphisms (SNPs) were then replicated in two independent French studies. This analysis lead to the discovery of ORM1 as a new gene participating to the control of TGP. Second, I followed a similar strategy using this time whole blood DNA methylation levels at CpG sites to identify DNA methylation marks involved in TGP variability. I analyzed the association between methylation-wide patterns from a French study and a French-Canadian families measured for TGP. Unfortunately, I did not identify robust associations between whole DNA methylation levels and thrombin generation.

Comme dans tout cancer, l'association entre myélome multiple et maladie thrombo-embolique veineuse est bien établie. Son incidence au cours du myélome est en moyenne de 10 à 20%. Elle semble plus élevée en cas de myélome de novo et lors de l’utilisation de traitements immunomodulateurs comme le thalidomide. Pourtant, la part de surcroît du risque de thrombose dû à ce traitement n’est pas encore très bien définie. Tout d’abord, nous avons réalisé un bilan de ces pathologies afin de délimiter le champ d’étude grâce à une revue de la littérature. Nous avons ensuite évalué l’incidence de la maladie thrombo-embolique veineuse, identifié les facteurs de risque thrombotique et évalué le classement en groupe de risque des patients présentant un myélome et traités par immunomodulateur grâce à une étude observationnelle, multicentrique, prospective, de la prise en charge des myélomes par les hématologues en France. Par la suite, nous avons réalisé l’analyse médico-économique du seul essai randomisé réalisé à ce jour sur la thrombophylaxie chez les malades présentant un myélome multiple traités par thalidomide en première ligne. Cette étude montre un gain de qualité de vie associé à des économies majeures lors de la prévention de la thrombose par aspirine plutôt que par héparine. Enfin nous avons réalisé 2 études médicales utilisant la génération de thrombine, test biologique de recherche. La première a été effectuée afin d’essayer de prédire les patients qui vont présenter une thrombose. La deuxième a pour but de rechercher l’existence d’une résistance à l’héparine aux doses habituelles utilisées dans cette pathologie / The association between multiple myeloma and venous thromboembolic disease is well established. This incidence in myeloma is on average from 10 to 20%. It appears to be higher in newly diagnosed myeloma and immunomodulatory drugs such as thalidomide might significantly increase the risk. However, the risk of thrombosis due to these treatments is not yet well defined. First, we performed a review of these diseases in order to delimit the field of this study through a literature review. Then, we evaluated the incidence of venous thromboembolic disease in patients with myeloma and treated with immunomodulatory, identified the thrombotic risk factors and evaluated the thrombotic risk assessment based on the physicians choice, through an observational, multicenter, prospective French study. Moreover, we performed the medico-economic analysis of the only randomized trial conducted to date on the thrombophylaxis in patients with multiple myeloma treated with thalidomide in the first line of chemotherapy. This analysis showed a gain in quality of life associated with significant cost savings in the prevention of thrombosis by aspirin rather than heparin. Finally we performed two medical studies using thrombin generation test, a global assay that measures the overall tendency of a plasma sample to form thrombin. The first study was conducted to predict patients who will have thrombosis. The second is performed to know if a heparin resistance with the usual doses in this pathology, exists

Introduction: L’obésité est un facteur connu d’hypercoagulabilité in vitro et in vivo. Cependant peu d’études se sont intéressées aux facteurs de risque d’hypercoagulabilité biologique chez le patient obèse morbide, à sa variation après chirurgie bariatrique (CB) ainsi qu’aux facteurs de risques de maladie thromboembolique veineuse (MTEV) postopératoire après CB. Matériel et Méthodes: Tous les patients destinés à une CB entre le 1er Septembre 2014 et le 31 Janvier 2016 au CHU de Brest étaient éligibles pour notre étude de cohorte locale et ont bénéficié d’un large bilan sanguin préopératoire et à 12 mois postopératoires, incluant des tests de génération de thrombine (GT) avec mesure du potentiel endogène de thrombine (ETP), une méthode validée globale d’évaluation de la coagulation. En parallèle, nous avons extrait de la base du SNIIRAM de l’assurance maladie, tous les patients opérés d’une CB entre le 1er Janvier 2012 et le 30 Septembre 2014 et déterminer la fréquence d’une MTEV dans les 90 jours suivants la CB. Résultats: Cent-deux patients étaient inclus dans notre étude de cohorte brestoise. Les facteurs de risque (OR (95% IC)) de présenter un ETP dans le 4ème quartile de distribution étaient : taux de cholestérol total augmenté (Pas=1mmol/l) (2,6 (1,2-5,4);P =0,01) et taux de fibrinogène augmenté (Pas=1 g/l) (2,2; (1,1-4,5);P = 0,03). A un an post-opératoire (%perte de poids: 33.1±8.3), on retrouvait une baisse significative de l’ETP (%) (111 (96-129) vs. 84 (72-102) ; P<0.001), du taux de fibrinogène (g/l) (4,2±0,8 vs. 3,6±0,8 ; P<0.001) et une baisse non significative du taux de cholestérol total (mmol/l) (4,8±0,8 vs. 4,6±1,0; P=0,08). Apres extraction à partir du SNIIRAM, 110.824 patients étaient inclus. Le taux de MTEV dans les 90 jours était de 0,51%. Les principaux facteurs de risque de MTEV retrouvés en analyse multivariée étaient (P<0.001): un antécédent de MTEV (6,41 (4,50-9,14)), des complications post-opératoires (9,23 (7,30-11,68)), une défaillance cardiaque (2,45 (1,48-4,06), une chirurgie par laparotomie (2,38 (1,59-3,45)), un IMC ≥ 50 kg/m² (1,67 (1,28-2,18)), une sleeve gastrectomy (2,02 (1,39-2,93)) et une procédure de deuxième intention (1,37 (1,10-1,72)). Conclusion : Sur une étude de cohorte de plus de 110.000 patients, nous identifions un taux faible de MTEV dans les 90 jours post-opératoires après CB dépendant de facteurs de risque individuels et liés à la chirurgie. De surcroit nous identifions une baisse de la GT à 1 an post-opératoire en parallèle à une perte de poids massive et à une diminution de l’état inflammatoire. / Introduction: Obese patients are known to be in an in vitro and in an in vivo hypercoagulable state relative to normal-weight patients. Studies focusing exclusively on morbidly obese patients are lacking. Our study aimed to identify markers of enhanced coagulability, to compare its evolution one year after bariatric surgery (BS) and to determine risk factors of venous thromboembolism (VTE) within 90 postoperative days. Methods: All patients scheduled for bariatric surgery (BS) between September 1, 2014 and January 31, 2016 in Brest University Hospital were eligible for our prospective local study. In vitro coagulation was assessed using thrombin generation (TG) tests (Endogenous thrombin potential (ETP)). Data on all patients undergoing BS in France from 1st January 2012 to 30 September 2014 were also extracted from the database of the French national health care (SNIIRAM) to determine the rate of VTE in the 90 days after surgery. Results: One hundred and two patients were included in our study assessing TG. Risk factors for enhanced TG (ETP in the 4th quartile) were increased total cholesterol level (Step=1mmol/l) (2.6 (1.2-5.4); P =0.01) and increased fibrinogen level (Step=1g/l) (2.2 (1.1-4.5); P=0.03). At 12 postoperative months, we found a significant lower ETP (%) (111 (96-129) vs. 84 (72-102 P<0.001)), fibrinogen level (g/l) (4.2±0.8 vs. 3.6±0.8; P<0.001)) and a non-significant trend for lower total cholesterol level (mmol/l) (4.8±0.8 vs. 4.6±1.0; P=0.08). After extraction of the SNIIRAM database, 110,824 patients were included with a rate of VTE of 0.51% (90 post-operative days). Main risk factors for postoperative VTE were (p<0.001): history of VTE (6.41 (4.50-9.14)), postoperative complications (9.23 (7.30-11.68)), heart failure (2.45 (1.48-4.06), open approach (2.38 (1.59-3.45)), BMI ≥ 50 kg/m² (1.67 (1.28-2.18)), sleeve gastrectomy (2.02 (1.39-2.93)) and redo procedure (1.37 (1.10-1.72)). Conclusions: Our study highlights the role of total cholesterol and blood inflammatory marker levels in enhancing TG in morbidly obese patients and shows a decrease of TG at 12 months after BS. The risk of postoperative VTE after BS is low depending on the individual risk level.

Die vorliegende Arbeit untersucht in einer Population von 132 gesunden Probanden die Hämostase mittels Calibrated Automated Thrombogram (CAT) und Rotationsthromboelastometrie (ROTEM). CAT wurde im plätchenarmen Plasma mit einer tissue factor (TF) von 1 und 5 pM durchgeführt. Lag time, Thrombin peak, Time to thrombin peak und das endogene Thrombin Potential (ETP) wurden ermittelt. ROTEM wurde ohne Aktivator durchgeführt (NATEM) und die Daten für Gerinnungszeit (clotting time, CT), Gerinnselbildungszeit, Alpha Winkel und maximale Gerinnselfestigkeit (MCF) mit den Daten der Thrombingenerierung korreliert. Es zeigte sich eine positive aber nicht lineare Korrelation bezüglich Alter versus lag time und time to peak, sowie eine annähernd lineare Korrelation bezüglich Alter versus thrombin peak und ETP. Für ROTEM konnte eine positive Korrelation bezüglich Alter versus MCF und Alpha Winkel, aber eine negative Korrelation bezüglich Alter versus CT dargestellt werden. In der Gegenüberstellung beider Assays korrelierten Thrombin peak und ETP (aktiviert mit einer TF Konzentration von 5 pM) signifikant mit dem Alpha Winkel und der MCF. Alle signifikanten Korrelationen zeigten lediglich eine moderate Regressionssteigung. / Published data on thrombin generation variables and their correlation with thromboelastometry in the healthy population are scarce. This study aimed at assessing thrombin generation in adults and its correlation to classical rotational thromboelastometry (ROTEM). Methods: Thrombin generation was measured in platelet-poor plasma from healthy volunteers using the calibrated automated thrombogram (CAT) with 1 and 5 pmol/l tissue factor final concentration. Lag time, thrombin peak, time to thrombin peak and endogenous thrombin potential (ETP) were analyzed. ROTEM was performed without activator (NATEM) and data for clotting time, alpha angle, clot formation time and maximum clot firmness were correlated with those of thrombin generation. Results: Altogether 132 persons (72 men, 60 women; median age: 48.0 years) were included. There was a positive non-linear correlation for age versus lag time (p < 0.001) and time to peak (p = 0.001), and almost linear correlation for age versus thrombin peak (p = 0.024) and ETP (p = 0.001), although with a moderate regression slope. Regarding ROTEM, there was a positive correlation between age and maximum clot firmness and alpha angle (p = 0.001), but a negative correlation between age and clotting time (p = 0.039). Comparing both assays, thrombin peak and ETP measured with a final tissue factor concentration of 5 pmol/l correlated significantly with alpha angle and maximum clot firmness. Conclusion: The age-related changes in CAT and ROTEM variables among adults are not linear. There is a significant correlation, although with a moderate slope, between data from CAT measured with 5 pmol/l tissue factor and ROTEM.

Cette étude avait comme objectif d’évaluer la coagulation par l’utilisation de la thrombélastographie (TEG®) et de la génération de thrombine (GT) chez des beagles en santé recevant de la prednisone ainsi que chez des chiens atteints d’hyperadrénocorticisme (HAC). Dans un premier temps, six beagles adultes en santé ont été évalués dans une étude prospective longitudinale au courant de laquelle chaque individu recevait 1 mg/kg/jour de prednisone par la voie orale pendant 2 semaines. Après un arrêt de traitement d’une durée de 6 semaines, ils ont finalement reçu 4 mg/kg/jour de prednisone pour encore 2 semaines. Les tracés TEG® et les mesures de la GT ont été obtenus au temps 0, à la fin des 6 semaines d’interruption de traitement, ainsi qu’à la suite des 2 dosages de prednisone. Suite aux 2 traitements avec la prednisone, des résultats significatifs,lorsque comparés aux valeurs de base, ont été obtenus pour la cinétique du caillot (« clot kinetics » ou K), l’angle alpha (α) et l’amplitude maximale (« maximal amplitude » ou MA). La GT avait augmenté de manière significative mais seulement après la dose de 1 mg/kg/jour de prednisone. Dans un deuxième temps, 16 chiens atteints d’HAC ont été évalués avant l’initiation d’un traitement pour leur condition. Quinze chiens ont été évalués par TEG® et 15 par GT. Les données obtenues ont ensuite été comparées aux valeurs normales. L’analyse par TEG® a démontré que 12/15 chiens avaient au moins un paramètre suggérant un état d’hypercoagulabilité. L’analyse par GT a démontré que 4/15 chiens avaient des changements compatibles avec un état d’hypercoagulabilité. Un test t-pairé pour des valeurs de variance inégales a démontré que le groupe de chiens atteints d’HAC avait des tracés hypercoagulables et un potentiel endogène de thrombine (« endogenous thrombin potential » ou ETP) plus élevé, lorsque comparé à la population de référence. / The purpose of this study was to use thrombelastography (TEG®) and thrombin generation (TG) to evaluate coagulation in healthy beagles receiving oral prednisone as well as client-owned dogs diagnosed with hyperadrenocorticism (HAC).Six healthy adult beagles were used in a prospective ongitudinal study whereby all dogs received 1 mg/kg of prednisone orally once daily for two weeks, followed by a 6-week washout period and then 4 mg/kg of prednisone orally once daily for two weeks. TEG® tracings and TG measurements were obtained at baseline, at the end of the washout period and at the end of both corticosteroid trials. Significant results as compared to baseline were obtained for clot kinetics (K), alpha angle (α)and maximum amplitude (MA), with tracings compatible with a hypercoagulable profile following both corticosteroid trials. Thrombin generation resulted in a significant increase in endogenous thrombin potential (ETP) after the 1 mg/kg/day trial only. Secondly, sixteen dogs affected by HAC were evaluated. Fifteen dogs were evaluated by TEG® and 15 dogs were evaluated by TG before treatment and compared to the normal reference values. For the TEG® analysis, 12/15 dogs had at least one parameter that suggested hypercoagulability. A paired t test for values with unequal variance was used to compare the HAC dogs to the healthy dogs and found that HAC dogs have hypercoagulable TEG® tracings. The same results were found when TG was used with the ETP elevated in the HAC dogs. However, when dogs were evaluated individually, only 4/15 had hypercoagulable TG results.

Chez le chien, la daltéparine est un anticoagulant utilisé pour la prévention et le traitement de la thrombose. La surveillance thérapeutique de la daltéparine par l’activité anti-facteur Xa (FXa) n’est pas un test fonctionnel. Cette étude avait pour but d’étudier l’emploi de la génération de thrombine (GT) pour évaluer les effets in vitro de la daltéparine sur du plasma canin, ainsi que pour détecter les effets pharmacodynamiques de la daltéparine administrée chez des chiens sains. Premièrement, les paramètres normaux de la GT ont été établis à partir du plasma de 25 beagles et 11 chiens sains de clients. Ensuite, des pools de plasma canin fortifié avec de la daltéparine, à dose croissante, ont été analysés selon la GT, l’activité anti-FXa et selon le temps de thromboplastine partielle activée (aPTT). Finalement, 24 beagles sains répartis au hasard dans 4 groupes on reçu soit une dose sous-cutanée (SC) de 50U/kg, 100U/kg ou 150U/kg de daltéparine ou un placebo. Du plasma pauvre en plaquettes (PPP) a été récolté pendant 24 heures et analysé selon la GT, l’anti-FXa et l’aPPT. In vitro, la daltéparine a démontré un effet anticoagulant sur la GT qui était concentration-dépendant. Les tests de GT et anti-FXa étaient plus sensibles aux effets de la daltéparine que l’aPPT. L’étude pharmacodynamique a démontré que le temps, la dose ainsi qu’une interaction temps*dose avaient un effet significatif sur les paramètres de GT et anti-FXa. La GT peut mesurer les effets pharmacodynamiques de la daltéparine à des doses variées chez des chiens sains. / Dalteparin is an anticoagulant used to prevent and treat thrombotic disorders in dogs. Measurement of anti-factor Xa (FXa) activity is currently used for monitoring therapy, but remains a non-functional test. The aim of this study was to investigate if a thrombin generation (TG) assay could be used for the in vitro evaluation of the effects of dalteparin on canine plasma, as well as for monitoring the pharmacodynamic effects of dalteparin administration in healthy dogs. Normal TG parameters were assessed in plasma from 25 adult beagles and 11 client-owned healthy dogs. Pooled plasma was spiked with dalteparin to obtain 9 final increasing concentrations. TG, anti-FXa activity and activated partial thromboplastin time (aPTT) were measured for each concentration. 24 healthy beagles were randomized across four equal groups. À single SC dose of 50 U/kg, 100 U/kg or 150 U/kg of dalteparin was given and compared to a placebo group. Platelet poor plasma (PPP) was collected over 24 hours and assed by TG, anti-FXa activity and aPTT. In vitro results showed that dalteparin exerted a concentration-dependent anticoagulant effect on TG parameters and TG and anti-FXa activity were more sensitive than aPTT to detect these effects. The pharmacodynamics study showed a time, dose and time*dose interaction that significantly affected TG and anti-FXa parameters. TG can be employed to measure the pharmacodynamics effects of dalteparin at different doses in healthy dogs.

Introdução: Pacientes com cirrose possuem altos níveis de fator VIII e preservação da trombomodulina (TM) (ativador da proteína C) apesar da redução global nas concentrações dos procoagulantes e anticoagulantes naturais. Isto não é levado em conta no teste de TP/INR, o qual não requer a adição de trombomodulina. Deste modo, o TP/INR não é capaz de demonstrar a magnitude da geração de trombina, em condições similares à que ocorre in vivo. De fato, o teste de TP/INR mede o lado procoagulante e se correlaciona com somente 5% do total de trombina gerada. Nossa hipótese é que a geração de trombina está bem preservada na cirrose, ainda que avançada, apesar dos resultados anormais do TP/INR, os quais indicariam coagulopatia. Objetivo: correlacionar os resultados do teste TP/INR com a geração de trombina nos pacientes com cirrose após procedimento invasivo (ligadura elástica de varizes esofagianas - LEVE). Pacientes e métodos: 97 pacientes foram consecutivamente incluídos no estudo (58 homens; 54±10 anos) e divididos em dois grupos INR < 1,5 e INR >= 1,5. Todos os pacientes passaram por uma criteriosa análise clínica e laboratorial, que incluiu revisão dos prontuários, determinação do TP/INR e da geração de trombina (ETP) com e sem adição de trombomodulina e cálculo do rETP (razão dos resultados com e sem adição de trombomodulina). Resultados: Não houve diferença significante na média dos valores de ETP sem trombomodulina no grupo INR < 1,5 (n=72), que foi 1.250±315,7 nmol/min quando comparada ao grupo INR >= 1,5 (n=25), cujos valores foram 1.186±238 nmol/min, p=0,3572. Após adição de trombomodulina, os valores mudaram para 893,0±368,6 e 965,9±232,3 nmol/min, respectivamente (p=0,6265). Ambos os grupos apresentaram preservação da geração de trombina, com valores mais elevados no grupo INR >= 1,5 do que no grupo de pacientes com INR < 1,5 (rETP 0,81±0,1 versus 0,69±0,2; p=0,0042). Evidência de hipercoagulabilidade (valores altos de rETP) foi demonstrada em 80% dos pacientes. Mesmo pacientes com INR >= 1,5 apresentam geração de trombina preservada, o que justificaria a baixa prevalência de sangramento após ligadura elástica de varizes esofagianas (5,2%; 3 pacientes no grupo INR < 1,5 e 2 pacientes no grupo INR >= 1,5). Conclusões: a geração de trombina se encontrou preservada nos pacientes com cirrose e os valores anormais de INR não refletiram a ocorrência de sangramento. A maioria dos pacientes mostrou evidência de hipercoagulabilidade, apesar do INR alargado. Sangramento após LEVE ocorreu em pequena parcela dos pacientes e não foi relacionado ao status da coagulação / Introduction: Patients with cirrhosis have higher levels of factor VIII and preservation of endothelial thrombomodulin (protein C activator) in spite of the global reduction in procoagulant and natural anticoagulant concentrations. This is not taken into account in the laboratory test of INR/PT, which does not require the addition of thrombomodulin and, thus, is not able to emulate the generation of thrombin that happens in vivo. In fact, INR/PT is a measure of procoagulant status and correlates with only 5% of the total amount of generate thrombin. We hypothesized that thrombin generation is well preserved in cirrhosis, even in advanced stages, despite the abnormal result of INR/PT, which would indicate coagulopathy. Aims: to correlated INR/PT with thrombin generation in patients with cirrhosis in the elective setting of an invasive procedure (endoscopic variceal ligation- EVL). Patients and Methods: 97 consecutive patients were prospectively included in this study (58 men; 54±10 years old) and divided into two groups INR < 1.5 and INR >= 1.5. All patients underwent a stringent clinical and laboratory assessment which included review of the clinical chart, INR/PT determinations and assessment of endogenous thrombin potencial (ETP) without and with the addition of thrombomodulin and calculation of the ETP ratio (rETP= without/with thrombomodulin). Results: There was no significant difference in the mean value of ETP without thrombomodulin that was 1,250±315.7nmol/min for patients with INR < 1.5 (n=72) and 1,186±238 in those with INR >= 1.5 (n=25); p= 0.3572. After the addition of thrombomodulin, values changed to 893.0±368.6 and 965.9±232.3, respectively (p= 0.6265). Both groups had preserved thrombin generation, which was higher in patients with INR >=1.5 than in patients with INR < 1.5 (rETP 0.81±0.1 versus 0.69±0.2; p=0.0042). Evidence of hypercoagulability (high rETP) was demonstrated in 80% of patients. Even patients with INR >= 1.5 had preserved thrombin generation, which is likely to account for the low prevalence of post-EVL bleeding (5.2%; n=3 with INR < 1.5 and n=2 with INR >= 1.5). Conclusions: thrombin generation was well preserved in patients with cirrhosis and was not reflected by abnormal results of INR. Most of the patients had evidence of hypercoagulability, despite enlarged INR. Post-procedure bleeding occurred in a small subset of the patients and was not related to the coagulation status

Introdução: O efeito da transfusão de plasma fresco congelado (PFC) para corrigir coagulopatia na cirrose ainda não foi devidamente esclarecido. As diretrizes internacionais permanecem sem uma indicação clara neste cenário e pacientes com cirrose chegam a consumir 30% do estoque de plasma dos bancos de sangue. Nosso objetivo foi avaliar o efeito do PFC na geração de trombina (GT) corrigida por trombomodulina (TM) em pacientes com cirrose e testes convencionais de coagulação alterados. Métodos: neste estudo observacional foram incluídos pacientes adultos, o i o om i g ó i o i o , RNI/TP >= 1,5 i i ç o PFC o médico assistente com intuitos profiláticos e/ou terapêuticos. Amostras de sangue foram coletadas antes e em até 6 horas após transfusão. O desfecho principal foi a melhora do parâmetro de GT, ETP adicionado de TM (ETP TM). Todas as amostras foram testadas para RNI/TP, TTPa e todos parâmetros de GT com e sem TM. Resultados: 53 pacientes receberam dose média de plasma de 11,26 ± 1,3 mL/kg. Após transfusão RNI, TP e TTPa diminuíram significantemente (p < 0,00001), correspondendo a melhora de 33,7%, 23, 5% e 16,6% respectivamente. Entretanto, foram atingidos valores <1,5 para RNI e TP em apenas 8 (15%) e 21 (40%) dos pacientes. O PFC aumentou a ETP TM em apenas 8% (1008 ± 345 a 1090 ± 341 nMol / L*min; p = 0,019). Antes da transfusão, evidência de GT normal ou alta foi encontrada em 96% por ETP TM e em 98% dos pacientes pelo parâmetro ETPr. Apenas 2 (3,8%) pacientes apresentaram valores de ETP TM abaixo da faixa normal e a transfusão de PFC corrigiu a geração de trombina em um deles. Nenhum destes sangrou. O ETP TM diminuiu em uma média de 12,8% em 18 (34%) pacientes após a transfusão (1270 ± 256 a 1107 ± 278 nMol / L* min ; p = <0,0001). O ETPrazão (com/sem TM) permaneceu praticamente inalterado (de 0,81 ± 0,13 para 0,80 ± 0,12, p = 0,75). Conclusão: Pacientes com cirrose e testes convencionais da coagulação alterados parecem ter GT preservada em seus estados basais. A transfusão de PFC aumenta a GT e melhora os testes convencionais de coagulação em um número limitado destes pacientes, e piorou a ETP TM em um terço dos casos / Background and aims: the efficacy of fresh frozen plasma (FFP) transfusion in correcting coagulopathy in cirrhosis has not been fully clarified. International manuals remain without a clear indication in this scenario and patients with cirrhosis consume up to 30% of the blood bank stock of plasma. Our aim was to assess the effect of FFP transfusion on thrombomodulin(TM)-corrected thrombin generation (TG) in patients with cirrhosis and impaired conventional coagulation tests. Methods: consecutive adult patients with INR/PT ratio >= 1.5 and receiving standard FFP dose for bleeding treatment and/or before invasive procedures were enrolled in this observational study. Primary endpoint was the amelioration of the GT parameter ETP with TM (ETPTM) after FFP transfusion (TM was added to mimic in vivo conditions). PT/INR, aPTT and all TG parameters (with and without TM) were examined in patients with cirrhosis before and after FFP transfusion. Results: 53 patients received FFP at a mean dose of 11,26 ± 1,3 mL/kg. FFP enhanced ETP TM by only 8% (1008±345 to 1090±341 nMol/L*min; p= 0.019). Before transfusion, evidence of normal or high TG was found in 96% by ETP TM and 98% of patients by the ETP ratio parameter. Only 2 (3.8%) had ETP TM values below normal range and FFP transfusion corrected thrombin generation in one of them. None of them bled. ETP TM had a 12.8% mean decrease in 18 (34%) after FFP transfusion (1270±256 to 1107±278 nMol/L*min; p= <0.0001). ETP ratio (with/without TM) remained practically unchanged (from 0.81 ± 0.13 to 0.80 ± 0.12, p = 0.75). FFP significantly ameliorated INR/PT values (p < 0.0001), but correction of INR and PT ratio for values <1.5 was observed in only 8 (15%) and 21 (40%) of the patients. Conclusions: Patients with cirrhosis and coagulopathy seem to have normal results of GT at baseline. FFP transfusion enhances TG and ameliorates conventional coagulations tests in a limited number of those patients, and might worsen ETP TM in in a third of cases

Introdução: Pacientes com cirrose possuem altos níveis de fator VIII e preservação da trombomodulina (TM) (ativador da proteína C) apesar da redução global nas concentrações dos procoagulantes e anticoagulantes naturais. Isto não é levado em conta no teste de TP/INR, o qual não requer a adição de trombomodulina. Deste modo, o TP/INR não é capaz de demonstrar a magnitude da geração de trombina, em condições similares à que ocorre in vivo. De fato, o teste de TP/INR mede o lado procoagulante e se correlaciona com somente 5% do total de trombina gerada. Nossa hipótese é que a geração de trombina está bem preservada na cirrose, ainda que avançada, apesar dos resultados anormais do TP/INR, os quais indicariam coagulopatia. Objetivo: correlacionar os resultados do teste TP/INR com a geração de trombina nos pacientes com cirrose após procedimento invasivo (ligadura elástica de varizes esofagianas - LEVE). Pacientes e métodos: 97 pacientes foram consecutivamente incluídos no estudo (58 homens; 54±10 anos) e divididos em dois grupos INR < 1,5 e INR >= 1,5. Todos os pacientes passaram por uma criteriosa análise clínica e laboratorial, que incluiu revisão dos prontuários, determinação do TP/INR e da geração de trombina (ETP) com e sem adição de trombomodulina e cálculo do rETP (razão dos resultados com e sem adição de trombomodulina). Resultados: Não houve diferença significante na média dos valores de ETP sem trombomodulina no grupo INR < 1,5 (n=72), que foi 1.250±315,7 nmol/min quando comparada ao grupo INR >= 1,5 (n=25), cujos valores foram 1.186±238 nmol/min, p=0,3572. Após adição de trombomodulina, os valores mudaram para 893,0±368,6 e 965,9±232,3 nmol/min, respectivamente (p=0,6265). Ambos os grupos apresentaram preservação da geração de trombina, com valores mais elevados no grupo INR >= 1,5 do que no grupo de pacientes com INR < 1,5 (rETP 0,81±0,1 versus 0,69±0,2; p=0,0042). Evidência de hipercoagulabilidade (valores altos de rETP) foi demonstrada em 80% dos pacientes. Mesmo pacientes com INR >= 1,5 apresentam geração de trombina preservada, o que justificaria a baixa prevalência de sangramento após ligadura elástica de varizes esofagianas (5,2%; 3 pacientes no grupo INR < 1,5 e 2 pacientes no grupo INR >= 1,5). Conclusões: a geração de trombina se encontrou preservada nos pacientes com cirrose e os valores anormais de INR não refletiram a ocorrência de sangramento. A maioria dos pacientes mostrou evidência de hipercoagulabilidade, apesar do INR alargado. Sangramento após LEVE ocorreu em pequena parcela dos pacientes e não foi relacionado ao status da coagulação / Introduction: Patients with cirrhosis have higher levels of factor VIII and preservation of endothelial thrombomodulin (protein C activator) in spite of the global reduction in procoagulant and natural anticoagulant concentrations. This is not taken into account in the laboratory test of INR/PT, which does not require the addition of thrombomodulin and, thus, is not able to emulate the generation of thrombin that happens in vivo. In fact, INR/PT is a measure of procoagulant status and correlates with only 5% of the total amount of generate thrombin. We hypothesized that thrombin generation is well preserved in cirrhosis, even in advanced stages, despite the abnormal result of INR/PT, which would indicate coagulopathy. Aims: to correlated INR/PT with thrombin generation in patients with cirrhosis in the elective setting of an invasive procedure (endoscopic variceal ligation- EVL). Patients and Methods: 97 consecutive patients were prospectively included in this study (58 men; 54±10 years old) and divided into two groups INR < 1.5 and INR >= 1.5. All patients underwent a stringent clinical and laboratory assessment which included review of the clinical chart, INR/PT determinations and assessment of endogenous thrombin potencial (ETP) without and with the addition of thrombomodulin and calculation of the ETP ratio (rETP= without/with thrombomodulin). Results: There was no significant difference in the mean value of ETP without thrombomodulin that was 1,250±315.7nmol/min for patients with INR < 1.5 (n=72) and 1,186±238 in those with INR >= 1.5 (n=25); p= 0.3572. After the addition of thrombomodulin, values changed to 893.0±368.6 and 965.9±232.3, respectively (p= 0.6265). Both groups had preserved thrombin generation, which was higher in patients with INR >=1.5 than in patients with INR < 1.5 (rETP 0.81±0.1 versus 0.69±0.2; p=0.0042). Evidence of hypercoagulability (high rETP) was demonstrated in 80% of patients. Even patients with INR >= 1.5 had preserved thrombin generation, which is likely to account for the low prevalence of post-EVL bleeding (5.2%; n=3 with INR < 1.5 and n=2 with INR >= 1.5). Conclusions: thrombin generation was well preserved in patients with cirrhosis and was not reflected by abnormal results of INR. Most of the patients had evidence of hypercoagulability, despite enlarged INR. Post-procedure bleeding occurred in a small subset of the patients and was not related to the coagulation status