Search

Severe ADAMTS13 deficiency defines thrombotic thrombocytopenic purpura (TTP). ADAMTS13 is responsible for VWF cleavage. In the absence of this enzyme, widespread thrombi formation occurs, causing microangiopathic anemia and thrombocytopenia, and leading to ischemic organ injury. Understanding ADAMTS13 function is crucial to diagnose and manage TTP, both in the immune and the hereditary form.ADAMTS13 role in coagulation homeostasis and the consequences of its deficiency are detailed. Other factors that modulate the consequences of ADAMTS13 deficiency are explained, such as complement system activation, genetic predisposition or the presence of an inflammatory status. Clinical suspicion of TTP is crucial to start prompt treatment and avoid mortality and sequelae. Available techniques to diagnose this deficiency and detect autoantibodies or gene mutations are presented, as they have become faster and more available in the last years.A better knowledge of TTP pathophysiology is leading to an improvement in diagnosis and follow-up, as well as a customized treatment in patients with TTP. This scenario is necessary to define the role of new targeted therapies already available or coming soon and the need to better diagnose and monitor at the molecular level the evolution of the disease.

Background The incorporation of genetic variables into risk scores for predicting venous thromboembolic events (VTE) could improve their capacity to identify those patients for whom thromboprophylaxis would be most beneficial. Proof‐of‐concept of this is provided by the TiC‐ONCO score for predicting the risk of VTE in patients with solid tumours. Our aim was to develop a similarly improved tool—the TiC‐LYMPHO score—for predicting VTE in patients with lymphoma. Methods In a retrospective observational study of 208 patients with lymphoma, 31 (14.9%) were found to have experienced an episode of VTE either at the time of diagnosis or over the next 6 months. Clinical variables associated with VTE, determined via logistic regression analysis, plus the same genetic variables included in the TiC‐ONCO score, were used to build the TiC‐LYMPHO score algorithm. The sensitivity, specificity, predictive values and AUC of the TiC‐LYMPHO, the Khorana and ThroLy scores were compared in the same population. Results The TiC‐LYMPHO score showed a significantly higher AUC, sensitivity and NPV (0.783, 95.35% and 97.98% respectively) than the other scores. The ThroLy score showed a significantly higher specificity (96.43% vs. 54.49%; p, This is a single‐centre observational study that analyses the utility of combining genetic and clinical variables in a thromboembolism risk score in patients with lymphoma. The TiC‐LYMPHO score showed a significantly higher AUC, sensitivity and NPV (0.783%, 95.35% and 97.98%, respectively) than the other scores. These results show that by incorporating genetic and clinical data into VTE risk assessment, the TiC‐LYMPHO score can categorize patients with lymphoma better in terms of their risk of VTE and allow individualized thromboprophylaxis to be prescribed.

Early descriptions of COVID-19 associated coagulopathy identified it as a disseminated intravascular coagulation (DIC). However, recent studies have highlighted the potential role of endothelial cell injury in its pathogenesis, and other possible underlying mechanisms are being explored. This study aimed to analyse the coagulation parameters of critically and noncritically ill patients with COVID-19 bilateral pneumonia, determine if coagulation factors consumption occurs and explore other potential mechanisms of COVID-19 coagulopathy. Critically and noncritically ill patients with a diagnosis of COVID-19 bilateral pneumonia were recruited. For each patient, we performed basic coagulation tests, quantification of coagulation factors and physiological inhibitor proteins, an evaluation of the fibrinolytic system and determination of von Willebrand Factor (vWF) and ADAMTS13. Laboratory data were compared with clinical data and outcomes. The study involved 62 patients (31 ICU, 31 non-ICU). The coagulation parameters assessment demonstrated normal median prothrombin time (PT), international normalized ratio (INR) and activated partial thromboplastin time (APTT) in our cohort and all coagulation factors were within normal range. PAI-1 median levels were elevated (median 52.6 ng/ml; IQR 37.2-85.7), as well as vWF activity (median 216%; IQR 196-439) and antigen (median 174%; IQR 153.5-174.1). A mild reduction of ADAMTS13 was observed in critically ill patients and nonsurvivors. We demonstrated an inverse correlation between ADAMTS13 levels and inflammatory markers, D-dimer and SOFA score in our cohort. Elevated vWF and PAI-1 levels, and a mild reduction of ADAMTS13 in the most severe patients, suggest that COVID-19 coagulopathy is an endotheliopathy that has shared features with thrombotic microangiopathy.

Acquired thrombotic thrombocytopenic purpura (aTTP) is still associated with a 10% to 20% death rate and its clinical course is characterized by recurrent episodes in up to 50% of cases. Over the last decade, mortality predicting models like the French TMA Reference Center Score and the Mortality In TTP Score (MITS) have been developed in an attempt to personalize treatment. The objective of the present study was to compare the results in both scores of de novo and relapsed aTTP episodes. For such purpose, a total of 29 episodes of aTTP (16 de novo and 13 relapses) were analyzed. All patients were homogeneously diagnosed and treated. First episodes had a higher score in both models in comparison with relapsed aTTP, (MITS median, 1 r: 1-4 vs 0 r: 1-2, P = .038 and French TMA Reference Center Score median, 2 r: 1-3 vs 1 r: 0-1, P = .006). The prevalence of neurological symptoms was significantly higher in the first episodes (P = .001) and patients >60 years old were more common in this group (P = .013), which may have been related to the results. Platelet count at presentation was higher in recurrences than in the first disease episode (P = .016) and ADAMTS13 activity

Allogeneic stem cell transplantation is the treatment of choice for acute myeloid leukemia (AML) patients. Unmanipulated haploidentical transplantation (Haplo-HSCT) is commonly used for those AML patients who need a timely transplant and do not have a suitable matched donor, but relapse rates are still high, and improvements are needed. Adoptive immunotherapy using natural killer cells (NK cells) could be a promising tool to improved Haplo-HSCT but, to date, no optimal infusion and manufacturing protocols have been developed.In this study, we describe a quick and reproducible protocol for clinical-grade production of haploidentical donor NK cells using double immunomagnetic depletion and enrichment protocol and overnight IL-15 stimulation.Thus, we have obtained 8 viable and functional NK cell products that have been safely infused to five AML patients undergoing unmanipulated Haplo-HSCT.Our results demonstrate the safety and feasibility of manufactured NK IL15 cells obtained from an adult allogeneic donor in the setting of haploidentical transplantation for AML patients.

Introduction Thrombotic thrombocytopenic purpura (TTP) is a life-threatening thrombotic microangiopathy characterized by microangiopathic hemolytic anemia, thrombocytopenia, and organ injury. TTP pathophysiology is based on a severe ADAMTS13 deficiency, and is a medical emergency with fatal outcome if appropriate treatment is not initiated promptly. Areas covered Authors will review the best options currently available to minimize mortality, prevent relapses, and obtain the best clinical response in patients with immune TTP (iTTP). Available bibliography about iTTP treatment has been searched in Library's MEDLINE/PubMed database from January 1990 until April 2021. Expert opinion The generalized use of plasma exchange marked a paradigm in the management of iTTP. In recent years, strenuous efforts have been done for a better understanding of the pathophysiology of this disease, improve diagnosis, optimize treatment, reduce mortality, and prevent recurrences. The administration of front-line rituximab and, more recently, the availability of caplacizumab, the first targeted therapy for iTTP, have been steps toward a further reduction in early mortality and for the prevention of relapses.

Thrombotic thrombocytopenic purpura (TTP) is a thrombotic microangiopathy (TMA) characterized by the development of microangiopathic haemolytic anaemia, thrombocytopenia, and ischaemic organ dysfunction associated with ADAMTS13 levels lower than 10% in most cases. Recently there have been numerous advances in the field of PTT, new, rapid and accessible techniques capable of quantifying ADAMTS13 activity and inhibitors. The massive sequencing systems facilitate the identification of polymorphisms in the ADAMTS13 gene. In addition, new drugs such as caplacizumab have appeared and relapse prevention strategies are being proposed with the use of rituximab. The existence of TTP patient registries allow a deeper understanding of this disease but the great variability in the diagnosis and treatment makes it necessary to elaborate guidelines that homogenize terminology and clinical practice. The recommendations set out in this document were prepared following the AGREE methodology. The research questions were formulated according to the PICO format. A search of the literature published during the last 10 years was carried out. The recommendations were established by consensus among the entire group, specifying the existing strengths and limitations according to the level of evidence obtained. In conclusion, this document contains recommendations on the management, diagnosis, and treatment of TTP with the ultimate objective of developing guidelines based on the evidence published to date that allow healthcare professionals to optimize TTP treatment.

Despite improvements in device design and hemocompatibility, intracranial hemorrhage and stroke remain the most feared and devastating complications in patients under mechanical circulatory support. We present the case of a 48 year old man with advanced heart failure (INTERMACS 3) and severe biventricular dysfunction who underwent biventricular pulsatile paracorporeal device implantation (Berlin Heart Excor) as a bridge to candidacy. Although on the heart transplantation waiting list, the patient experienced an intracranial hemorrhage, which was successfully managed by switching to a less thrombogenic biventricular assist device (Levitronix Centrimag) using the Excor cannulae, thus enabling temporary withdrawal of antithrombotic therapy. Heart transplant was performed successfully with no significant complications.

Acquired thrombotic thrombocytopenic purpura (aTTP) is still associated with a 10% to 20% death rate and its clinical course is characterized by recurrent episodes in up to 50% of cases. Over the last decade, mortality predicting models like the French TMA Reference Center Score and the Mortality In TTP Score (MITS) have been developed in an attempt to personalize treatment. The objective of the present study was to compare the results in both scores of de novo and relapsed aTTP episodes. For such purpose, a total of 29 episodes of aTTP (16 de novo and 13 relapses) were analyzed. All patients were homogeneously diagnosed and treated. First episodes had a higher score in both models in comparison with relapsed aTTP, (MITS median, 1 r: 1-4 vs 0 r: 1-2, P = .038 and French TMA Reference Center Score median, 2 r: 1-3 vs 1 r: 0-1, P = .006). The prevalence of neurological symptoms was significantly higher in the first episodes (P = .001) and patients60 years old were more common in this group (P = .013), which may have been related to the results. Platelet count at presentation was higher in recurrences than in the first disease episode (P = .016) and ADAMTS13 activity5% was more frequent in the last group (P = .016). There was no significant difference in the rate of refractoriness or exacerbations. In conclusion, first aTTP episodes had a higher probability of short-term mortality compared to relapsed aTTP episodes according to the MITS and French TMA Reference Center Score.

INTRODUCTION Coronavirus disease 2019 (COVID-19) caused by SARS-CoV2 virus is thought to be more severe in patients with prior hematological diseases. There is evidence suggesting that hematological patients are particularly vulnerable and have a higher risk of developing severe events, with higher mortality rate than general population. However, the available data are limited, and prognostic factors at admission still remain unclear. With this background, our aims were to analyze the impact of hematological diseases and their therapy on the COVID-19 severity and to identify clinical and biological risk factors to predict the outcome in these patients. METHODS We carried out a multicenter retrospective observational study with data collection from 19 Spanish centers. A total of 491 patients with hematological diseases who developed COVID-19 (HEMATOCOVID patients) from March 8th to June 9th were included in the study. Clinical and biological data were collected at the time of emergency room assistance or hospital admission. For statistical analysis, chi-square test and Mann-Whitney U-test were used to identify differences between groups. The effects of multiple predictor variables on COVID-19 outcomes were assessed by logistic binary regression. RESULTS The geographic distribution of the studied HEMATOCOVID patients was similar to the national geographic spread of the COVID-19 (Figure 1). Most patients (94,3%) were confirmed cases of COVID-19 with a positive result on SARS-CoV2 RT-PCR on a nasopharyngeal swab or serologic testing, and 15% were nosocomial infections. The mean age was 71 years with 57% males, and 70% had at least one associated comorbidity. The most frequent hematological diseases among COVID-19 patients were Lymphoid Malignancies (53,8%), and 51,7% of patients were on active treatment. Most common symptoms were fever (59%), cough (54%) and dyspnea (46%), with associated pneumonia in 70% of cases. Hospital admission was required in 89% of patients and 6,3% were admitted to intensive care units. Mortality rate was about 36%. Non-survival patients were older and had a higher Charlson comorbidity index and ECOG performance status. Furthermore, patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS), and those with an active or progressive hematological disease at the diagnosis of COVID-19 had higher mortality. Patients who had undergone hematopoietic stem cell transplantation (autologous, allogeneic, and both) had better outcomes. Other factors such as low lymphocyte and platelets counts, or high lactate dehydrogenase (LDH), C-reactive protein (CRP) and procalcitonin values were also associated with poorer outcomes (Table 1). In addition, COVID-19 therapy had no impact on survival, except for corticosteroids, that correlated with a negative impact (p < 0,001) probably because they were not administrated to patients with less severe COVID-19. Multivariate regression analysis showed the following risk factors for death: age >70 years, ECOG ≥2, absolute lymphocyte count ≤0.6·109/L, platelet count ≤40·109/L, high LDH (higher than upper normal limit) and CRP >11 mg/dL (Table 2). CONCLUSIONS SARS-CoV2 infection causes more severe disease and higher mortality rates in hematological patients, especially those with AML/MDS or active/progression status disease. In addition, advanced age, co-morbidities, poor performance status, low lymphocyte and platelet counts and high LDH and CRP at admission are associated with poorer survival. This worse disease evolution could be explained by the immunosuppression state induced by underlying disease and treatments received. These particular features should be taken into account for a population that is highly exposed to SARS-CoV2 contagion due to high number of hospital visits for treatment. Disclosures Hernandez-Rivas: Janssen: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Membership on an entity's Board of Directors or advisory committees; Rovi: Membership on an entity's Board of Directors or advisory committees. Ocio:MDS: Honoraria; Asofarma: Honoraria; Takeda: Honoraria; GSK: Consultancy; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Secura-Bio: Consultancy; Oncopeptides: Consultancy. López Jiménez:Gilead: Research Funding, Speakers Bureau; Janssen: Research Funding, Speakers Bureau; Roche: Research Funding, Speakers Bureau; MSD: Speakers Bureau; Takeda: Speakers Bureau; Abbvie: Research Funding, Speakers Bureau. Córdoba:Takeda Farmacéutica España S.A.: Speakers Bureau; Janssen: Honoraria, Other: travel and accommodation; Abbvie: Honoraria, Other: travel and accommodation; Roche: Honoraria, Other: travel and accommodation; Gilead: Honoraria, Other: travel and accommodation. Moraleda:Takeda: Consultancy, Other: Travel Expenses; Sandoz: Consultancy, Other: Travel Expenses; Novartis: Consultancy, Other: Travel Expenses; Gilead: Consultancy, Other: Travel Expenses; Jazz Pharmaceuticals: Consultancy, Research Funding. Garcia-Sanz:Takeda: Consultancy, Research Funding; Pharmacyclics: Honoraria; Novartis: Honoraria; Janssen: Honoraria, Research Funding; Incyte: Research Funding; Gilead: Honoraria, Research Funding; BMS: Honoraria; Amgen: Membership on an entity's Board of Directors or advisory committees.

Introduction: Idarucizumab is a humanized monoclonal antibody fragment that binds to dabigatran and reverses its anticoagulant activity. It has been available in Spain since June 2016 and is indicated for imminent surgery or invasive procedures and life-threatening bleeding. The aim of the study was to describe the actual experience with idarucizumab in different centers in Madrid. Methods: Patients with electronic prescription of idarucizumab between June 2016 and July 2021 were included. Demographic information, comorbidities, laboratory parameters, dabigatran indication, anticoagulation resumption, adverse events related to idarucizumab and death within 30 days were collected from medical records. Qualitative data are presented as frequencies and percentages. Quantitative data are presented as mean ± standard deviation (SD) or median (interquartile range -IQR-). Cumulative survival was calculated by dividing the number of patients alive by the number of patients in each indication category for idarucizumab in a 30-day post-infusion period. Results: A total of 69 patients from 8 hospitals in Madrid were included. Ninety-six percent received dabigatran for prevention of stroke and embolism in nonvalvular atrial fibrillation and 4% received it for the treatment of thromboembolic disease. The mean age was 73.5 ± 13.9 years, and 55.6% were men. Median aPTT was 45.6 seconds and was prolonged in 72.1% (49). Patient characteristics, concomitant conditions and laboratory parameters are reviewed in Table 1. The main indication for idarucizumab was reversal of anticoagulation for persistent bleeding (46.4%), followed by surgery (44.9%). Fibrinolysis due to ischemic stroke was performed in 3 patients (4.3%), dabigatran intoxication occurred in 3 patients due to acute renal failure (4.3%). Gastrointestinal bleeding was the most common type of bleeding. Two of the patients intoxicated with dabigatran also had gastrointestinal bleeding. Cardiac surgery was the most common type of intervention, with heart transplant being a common indication (9/13). Minor surgical procedures included 2 lumbar punctures and 1 central venous catheterization. In one case, the type of surgery was not available. Figure 1 A and B summarize the bleeding location and type of surgery. The median time between infusion of idarucizumab and cessation of bleeding or onset of surgery was 3 hours, however this information was only available in 43 patients. No reports of excessive bleeding during surgery or after fibrinolysis were noted. One patient with dabigatran intoxication was reported to have an episode of persistent melena in which the trough plasma level was 1178.1 ng/mL. This patient died of an aggressive lymphoproliferative disorder that couldn´t be biopsied due to altered coagulation. A case of auricular thrombosis occurred in a patient with a heart transplant due to hyperthophic cardiomiopathy and end-stage heart failure requiring thrombectomy. The patient required a biventricular assistance and died of myocardial infarction. Full 30-day follow-up was available for 68 patients, during this period 11 died. Five patients in the bleeding group died, 3 from hypovolemic shock, 1 from intraparenchymal hemorrhage and data were missing for 1. Two patients who received a heart transplant died, one as described previously 10 days after the transplant and the other 2 days after the transplant from hemorrhagic shock. Three patients who underwent abdominal surgery died of septic shock. One patient with dabigatran intoxication died. Cumulative survival after a follow-up period of 30 days was 86% (Figure 2). Seventy-seven percent (53) resumed anticoagulation after a median of 3 days (0-180), and 62.3% (33) were bridged with low molecular weight heparin (LMWH) at prophylactic doses. Finally, 75% (40) maintained LMWH (7) or restarted dabigatran or another direct oral anticoagulant (33). A total of 13 patients didn´t resume any anticoagulation. Conclusions: Idarucizumab is an effective drug for reversal of dabigatran anticoagulation in bleeding or imminent surgery/invasive procedures. In this cohort it was used safely in patients awaiting a heart transplant. No cases of bleeding after infusion or during surgery were reported, except for a single case of auricular thrombosis. Most patients resumed anticoagulation at discharge. The experience described confirms the safety of idarucizumab in daily clinical practice. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Introduction: Autoimmune thrombotic thrombocytopenic purpura (aTTP) is a severe disease caused by the production of autoantibodies against von Willebrand factor (vWF)-cleaving ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin-1 motifs; 13th member of the family). Without functional ADAMTS13, endothelial cells-derived unusually large vWF (ULVWF) multimers are present and are responsible for platelet clumping in the microvasculature. Plasma exchange (PE) and immunosuppressive therapy with steroids and rituximab are the milestones of the treatment of this disease. Moreover, in 2018, nanobody caplacizumab was approved for the treatment of adult patients with an acute episode of aTTP. Our objective was to retrospectively review the efficacy and safety of the current use of caplacizumab in Spain. Methods: We collected demographic, clinical, and laboratory data of patients with aTTP who were reported in the TTP Spanish Registry from 15 centres between July 2018 and July 2020. All patients were diagnosed with aTTP because of the presence of microangiopathic hemolytic anemia (MAHA), thrombocytopenia, organ dysfunction, ADAMTS13 activity less than 5% and the presence of ADAMTS13 autoantibodies. Qualitative data are presented as number (frequencies). Quantitative data are presented as mean ± standard deviation (SD) or median (interquartile range -IQR-) when appropriate. A correlation test was performed to determine the linear relationship between number of days since diagnosis to caplacizumab start and number of days since diagnosis to the first day with >150x109/L platelets. Results: Our series comprises 30 patients: 22 (73%) females and 8 (27%) males with a median age of 45 (IQR: 31-55). At presentation, neurologic abnormalities were seen in 18 (60%) patients, symptoms and signs of anemia were present in 15 (50%) patients, and bleeding was present in 10 (33%) patients. Fever was present in 1 (3%) patient. Laboratory tests showed hemoglobin 92±28 g/L, platelet count 19±16 x109/L, unconjugated bilirubin 2.33±1.76 mg/dL, LDH 1,467±1,428 IU/L, and creatinine 1.0±0.45 mg/dL. Median ADAMTS13 activity was 0 (IQR: 0-0.5) and ADAMTS13 autoantibodies were positive in all cases. After diagnosis, treatment was started with PE and steroids in all patients after a median of 0 days (IQR: 0-0) and patients received a median of 10 PE procedures (IQR: 7-13). Caplacizumab was administered to all patients with a median of 3 (IQR: 1-9) days after diagnosis and it was administered during 36 days (IQR: 31-39). No severe adverse events were reported with the use of caplacizumab. Rituximab was added in 19 (63%) patients after a median of 4 days (IQR: 14-21). Time to platelet normalization (>150x109/L) was 5.5 days (IQR: 4-17) after diagnosis. The longer the delay in administering caplacizumab after diagnosis, the longer the delay in platelet normalization (Pearson's correlation coefficient, r=0.94 (95% CI: 0.86 to 0.98; R2=0.89; p Conclusion: Caplacizumab was an efficacious and safe drug to treat adult patients with acute episodes of aTTP. A statistically significant strong positive linear correlation was observed between number of days from diagnosis to caplacizumab start and number of days from diagnosis to the first day with >150x109/L platelets. Disclosures No relevant conflicts of interest to declare.

INTRODUCTION COVID-19 is associated with coagulopathy that correlates with poor prognosis. Although the underlying mechanism of COVID-19 coagulopathy remains unknown, early reports suggested that it may be a form of disseminated intravascular coagulation (DIC). However, recent studies have highlighted the potential role of endothelial cell injury in its pathogenesis. AIMS The aims of our study were to analyze the coagulation parameters of critically and non-critically ill patients with COVID-19 pneumonia admitted to our hospital, determine if coagulation factors consumption occurs, identify potential prognostic biomarkers of this new disease and explore possible underlying mechanisms of COVID-19 coagulopathy. METHODS We conducted a retrospective cohort study performed at Gregorio Marañon Hospital in Madrid, Spain. Adult patients with a diagnosis of COVID-19 hospitalized in our center were recruited, including those admitted to the ICU and to general wards. Patients were randomly selected from blood samples that arrived at our Hemostasis laboratory during April 2020. For each patient, we conducted a complete analysis of coagulation parameters, including basic coagulation tests, quantification of coagulation factors and physiological inhibitor proteins, evaluation of the fibrinolytic system and determination of von Willebrand Factor (vWF) and ADAMTS13. Laboratory data were compared with clinical data and outcomes. Data were analyzed using IBM SPSS Statistics for Mac, version 24. This study was approved by our institutional Ethics Committee and it was executed along with the international ethics recommendations for conducting research in humans following the latest revision of Declaration of Helsinki. RESULTS A total of 62 patients (31 ICU, 31 non-ICU) were analyzed. Mean age of the sample was 61.8 (SD 15.2) years and 69.4% of the patients were male. The coagulation parameters assessment demonstrated normal median PT, INR and APTT in our cohort and all coagulation factors were within normal range. Factor VIII showed an increasing trend (194.5±71.9) which could be interpreted as an acute phase reactant, and it was significantly higher in non-survivors (p=0.003). Similarly, we did not observe consumption of physiological inhibitor proteins and platelet counts were also within the normal limits, despite being slightly lower in non-survivor patients (p=0.006) (Table 1). Von Willebrand Factor (vWF) was above the normal range (median 216%, IQR 196-439, normal range 62-175%) in our cohort and higher levels of vWF-antigen (p=0.001) and vWF-activity (p=0.02) were associated with poor prognosis. Likewise, a lower ADAMTS13 activity was observed in non-survivors (p=0.008). Regarding the fibrinolytic pathway, PAI levels were above the normal range (median 52.6ng/ml, IQR 37.2-85.7, normal range 4-40ng/ml), but we found no statistically significant differences based on survival. The remaining parameters of the fibrinolytic pathway (plasminogen and alpha-2 antiplasmin) were within normal range (Table 1). ICU-patients had a poorer prognosis, with a higher rate of mortality (p=0.003). Likewise, they showed more elevated acute phase reactants (p CONCLUSIONS COVID-19 infection is associated with coagulopathy that correlates with poor prognosis. However, coagulation factors, physiological inhibitory proteins and alpha-2-antplasmin levels were preserved in our study. Similarly, we did not observe platelets or fibrinogen consumption, which leads us to assume that COVID-19 coagulopathy is not a form of DIC. Increased vWF and decreased ADAMTS13 activity in our cohort could indicate that the underlying mechanism of this coagulopathy may reside in the endothelial cells and share a similar pathogenesis with thrombotic microangiopathy (TMA), as it has been recently suggested in some scientific reports. Disclosures No relevant conflicts of interest to declare.

Introduction: Acquired thrombotic thrombocytopenic purpura (aTTP) is a rare disease characterized by a severe deficiency of the enzymatic activity of ADAMTS13 caused by autoantibodies, with an incidence of 3-4 x106inhabitants per year according to the few published data available. Accurate estimates of the incidence of aTTP are important to assess the resources required for current treatments and to anticipate the need to develop new treatments. The aim of this study was to determine the actualincidence of aTTP in Spain, as well as its diagnosis, management, and associated complications. Material and methods:A cross-sectional surveywascarried out among hematologists working in Spanish hospitals by means of an email that was sent to all members of the three main hematological scientificsocieties of Spain. All participants were asked to report the number of patients over the age of 16 years with a de novodiagnosis and relapses examined between Jan 2015 and Dec 2017. They were also asked about the number of patients that were known and alive in each hospital without having experienced any episode during such period. The population area of each participating hospital was consideredto calculate the incidence and prevalence of the disease. We also estimated the hospitalization service, mean hospital stay, percentage of ADAMTS13 activity at diagnosis and during follow-up, initial management, refractory cases and exacerbations (as defined by Scully et al.), treatment-related complications, and sequelae of aTTP. The median, interquartile ranges, and percentages were used for the descriptive analysis. Given that no personal data were treated, this study did not require the approval of a Research Ethics Committee. Results:A response was received from 42 centers (Figure 1). All hospitals except a private one belonged to the Spanish public health system, which provides health coverage to the entire Spanish population.A total of 203 episodes were reported (138 new episodes). The calculated population of the participating centers was nearly 21 x 106inhabitants. The incidence was 2.25 x106inhabitants per year, and the prevalence 19 x106inhabitants. Six patients died before they could start treatment (all but one in first episodes) and five were sent to other hospitals; thus, a total of 192 episodes were eventually treated. Table 1 and 2 show the data of the enzymatic activity of ADAMTS13 and the ADAMTS13 inhibitor at diagnosis, as well asthe complications. Plasma exchange (PEX) was performed by the Hematology and Nephrology Departments of 29 (70.7%) and 12 (29.3%) hospitals, respectively. The median hospital stay was 14 days (IQR: 10-20). Seventy-five episodes (39.1%) required admission to the intensive care unit with a median stay of 4 days (IQR: 3-7). During first-time episodes, a median of 12 PEX procedures (IQR: 8-19) were performed per patient, whereas in the case of relapses, a median of 9 (7-10) PEX procedures were carried out per patient. One plasma volume (PV) was used in the PEX procedures performed in 34% of the episodes, while 1.5 PVs were used in 56% of the episodes, and other PVs were used in the remaining 9.8%. The median duration of the PEX procedures was 121 minutes (IQR: 118-180). PEX and corticosteroids were the initial treatments administered in 98.4% of the episodes. Rituximab was used as a first-line treatment for new episodes in 18 of the 127 patients (14.1%), as a second-line treatment in 34 patients (26.6%), and as a prophylactic treatment (followingremission) in 4 patients (3.5%). In addition to the 6 early deaths, 9 patients died despite receiving the treatment (15 of 203 episodes, accounting for a mortality rate of 7.3%). Refractoriness to the PEX + corticoids was observed in 31 episodes of the 192 ones treated (16.1%), and at least one exacerbation (26.5%) took place in 51 episodes. Conclusion.Wecalculated the incidence ofclinically diagnosed aTTP associated with a severe ADAMTS13 deficiency inalmost half of the Spanish population which provided a high accuracy to our findings. These data are concordant with those published previously in other countries. Despite the currently available therapies, considerable rates of refractoriness and mortality still persist.Our data will be very useful for estimating the budget invested in this pathology and proposing standards for the diagnosis and treatment of this disease in our region. Disclosures Pascual Izquierdo: Novartis: Consultancy; Sanofi: Consultancy. De La Rubia:AMGEN: Consultancy; Celgene Corporation: Consultancy; Takeda: Consultancy; AbbVie: Consultancy; Janssen: Consultancy. Mingot-Castellano:Novartis: Consultancy; Novonordisk: Consultancy; Roche: Consultancy; Takeda: Consultancy; Bayer: Consultancy; Amgen: Consultancy; CSL Behring: Consultancy; Sobi: Consultancy.

Background: Successful discontinuation of eltrombopag in certain immune thrombocytopenia (ITP) patients after complete response has already been demonstrated. However, the frequency of this phenomenon and type of candidate patients are still matter of discussion. Moreover, possibility of long term discontinuation responses is not clearly established. Methods: Here we retrospectively evaluated our whole cohort of 508 adult patients (aged 18 years or more) with primary ITP treated with eltrombopag included in the Spanish Eltrombopag Registry with a focus on the patients who achieved a durable (at least six months) platelet response after stopping eltrombopag. Successful discontinuation of eltrombopag (SDOE) was defined as those patients who reached remission and maintained platelet counts ≥ 50x109/l for at least 6 months in absence of eltrombopag or any rescue therapies administered. Long term discontinuation of eltrombopag (LTDOE) was defined as those patients who reached remission and maintained platelet counts ≥ 50x109/l for at least 36 months in the absence of eltrombopag or any rescue therapies administered. The study was approved by the Hospital Universitario de Burgos Ethics Committee and fulfilled Helsinki declaration standards. Results: While 37.4% of our patients relapsed of ITP with subsequent platelet count drop sometime during first six months of discontinuation of eltrombopag, a total of 74 patients (14.6%) were able to achieve SDOE. The median age of SDOE patients was 62 [range, 47-79] years. There were 47 women and 27 men. According to the standard definition, patients were allocated to newly diagnosed (n=17), persistent (n=15) and chronic (n=42) ITP groups. The median time from diagnosis to eltrombopag initiation was 31 [range, 4-104] months. The median number of previous therapies was 2 [range, 1-2], including splenectomy (14%), rituximab (18%) and romiplostim (12%). As expected, all patients but 1 achieved a complete response (platelet count ≥100 x 109/L) prior to eltrombopag discontinuation The median duration of eltrombopag treatment was 7 [range, 2-19] months. Reasons for eltrombopag discontinuation were: persistent response despite a reduction in dose over time (n=43), platelet count >400x109/L (n=16), aspartate aminotransferase elevation (n=5), diarrhea (n=4), thrombosis (n=3), patient's request (n=2) and other reasons (n=1). Analysis of these SDOE discontinued patients show that with a median follow-up of 55 [range, 29-79] months, 38 patients (51.3%) maintained treatment-free response 36 months after stopping eltrombopag with no need of additional ITP therapies (median time of eltrombopag discontinuation was 70 [range, 50-77] months).This condition is what we define now as LTDOE. Nevertheless, 36 patients relapsed beyond 6 months but before 36 months of eltrombopag discontinuation (median time of eltrombopag discontinuation was 10 [range,7 -22] months). Characteristics of LTDOE population were a median time since ITP diagnosis of 32 [range, 5-88] months with 15/38 patients having ITP The main characteristics (age, gender, duration of ITP, prior ITP lines, platelet count before starting eltrombopag, duration of eltrombopag treatment, and platelet count before eltrombopag withdrawal) of the 38 patients with LTDOE were compared with those of the SDOE cohort who did not achieve a LTDOE. Unfortunately, no predictive factors of LTDOE could be identified. Conclusion: Durable platelet response following eltrombopag cessation may be observed in only 15% of primary ITP patients treated with this drug. On the contrary, half of patients who achieve a sustained response after eltrombopag withdrawal will get a long term discontinuation. However, we are lacking predictor factors for successful and long-term discontinuation of eltrombopag in primary ITP. Disclosures Gonzalez-Lopez: Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau. Pascual Izquierdo:Novartis: Consultancy; Sanofi: Consultancy. Sánchez-González:Amgen: Consultancy, Speakers Bureau; Gilead: Speakers Bureau; Navartis: Consultancy, Speakers Bureau; Shire: Speakers Bureau; Takeda: Consultancy, Speakers Bureau. Jarque:Takeda: Consultancy, Speakers Bureau; Shire: Consultancy, Speakers Bureau; Shionogi: Consultancy, Speakers Bureau; Servier: Speakers Bureau; Roche: Consultancy, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; MSD: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Grifols: Consultancy; Gilead: Consultancy, Speakers Bureau; CellTrion: Consultancy; Celgene: Consultancy, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Abbie: Consultancy, Speakers Bureau; Alexion: Consultancy, Speakers Bureau.

Objectives To evaluate the level of concordance between the 2007 PRETEMED guidelines and the 2012 American College of Chest Physicians (ACCP) guidelines in medical patients at admission. Methods A cross-sectional, observational and descriptive study was designed and included all adult medical patients admitted from an emergency department. Firstly, patients classified as low-moderate risk and high risk according to PRETEMED were compared to those classified by ACCP as low and high risk. Secondly, the same analysis was performed but this time low and moderate-high risk patients according to PRETEMED were compared to ACCP low and high risk patients. The level of concordance was calculated using the kappa concordance index. The study was approved by the Ethics Committee for Clinical Research of the hospital. Results The analysis was performed with 207 patients; 53.1% were male and the median age was 75.3 years (minimum 18, maximum 100 years old). The most common diagnosis at admission was related to a respiratory disease (37.2%). The level of concordance was 0.59 (95% CI 0.48 to 0.70) when moderate risk patients were grouped with low-risk patients and 0.53 (95% CI 0.42 to 0.65) when moderate risk patients were grouped with high-risk patients. Conclusions The level of concordance between both guides is moderate. It would be helpful to confirm whether the level of agreement improves when the patient9s condition stabilises after several days of hospitalisation.

Abstract 4397 OBJECTIVES Thrombotic events have been reported as a major cause of morbidity after the Fontan procedure. There is no consensus about the type and duration of postoperative anticoagulation prophylaxis, due to the high risk of bleeding complications, the difficulties in monitoring and the questionable therapeutic compliance in children. In spite of the lack of long term prospective studies in this situation, the ACCP has recommended in their guidelines OAT following Fontan or Glenn operation for at least 6 months. This has also been our practice in our institution during the period of study. AIM OF THE STUDY To analyze the efficacy and complications of OAT in our pediatric patients after undergoing the Fontan operation. METHODS Retrospective chart review of all the children treated with OAT in our institution between 1995 and 2009. All patients were treated initially with acenocumarol 0,2 mg/kg, except the Fontan patients, who received 0,1 mg/kg. Target INR was 2–3 for all patients. The Mann-Whitney test was used to compare the rate of complications, and the percentage of visits out of target INR between the Fontan patients and the rest of the cohort. RESULTS There were 61 children (26 female/35 males) aged between 1 month and 17 years, who received OAT with a range of follow up between 4 months and 14 years: 27 after Fontan operation (Group A), an 34 for other reasons (Group B: n=13 non prothetic valve cardiopathy, n=21 treatment of thromboembolic disease). The average follow-up was similar in both groups (median of 6.5 months in group A vs.7.5 months in group B). There were few complications: 1 mild epistaxis and 1 thrombotic event in group B, and none in group A. There were no differences in the proportion of controls in normal range between both groups; there was a moderate proportion of controls outside the target range of INR, with higher distribution below the range than above the range. The median dose used to achieve the target INR was 0.3 mg/kg/d in Group A and 0.4 mg/kg/d in Group B. CONCLUSIONS Oral Anticoagulant therapy is safe and effective in pediatric patients,with very low rates of thrombotic or hemorragic complications including those undergoing the Fontan surgery. There were not any differences between both groups in any of the analizyed parameters. Disclosures: No relevant conflicts of interest to declare.