Acquired factor XIII deficiency in patients under therapeutic plasma exchange: A poorly explored etiology.

INTRODUCTION: Factor XIII (FXIII) deficiency may cause bleeding under certain clinical circumstances. Therapeutic plasma exchange (TPE) may lead to a transient deficiency. OBJECTIVES: To describe the clinical evolution of patients with acquired FXIII deficiency secondary to TPE. METHODS: We respectively studied a cohort of consecutive patients from 2014 to 2019 who were treated with TPE with FXIII levels <50%. The FXIII was measured after the start of the TPE course, on days between the TPE sessions, due to suspected acquired deficiency. All TPE were performed using continuous flow cell separator. In all cases, the initial replacement fluid applied was albumin. Apheresis procedures were held at 24to 48 hours intervals. RESULTS: Eighteen patients were included, 13 of them were recipients of kidney transplants. The main TPE prescription was humoral rejection. Median FXIII at diagnosis (measured on days between sessions of the TPE course) was 19%(IQR17-25). The median of apheresis procedures before measurement of FXIII was 3(IQR2-4). Among the total cohort, 10 patients suffered hemorrhages. None of the patients without history of kidney transplants had bleeding (n = 5), however, 10/13 with kidney transplants did. Five kidney transplant patients received therapy with FXIII concentrate because of life-threatening bleeding. In all cases, the bleeding stopped within the first 24 hours. All patients had their FXIII levels measured again after finishing the TPE course, with normal results. CONCLUSIONS: TPE is an under-diagnosed cause of acquired FXIII deficiency since routine coagulation tests remain unaltered. It might cause major bleeding, particularly in patients with a recent history of surgery like kidney transplants.

Rivaroxaban Levels in Patients' Plasmas are Comparable by Using Two Different Anti Xa Assay/Coagulometer Systems Calibrated with Two Different Calibrators.

BACKGROUND: Rivaroxaban oral anticoagulant does not need laboratory monitoring, but in some situations plasma level measurement is useful. The objective of this paper was to verify analytical performance and compare two rivaroxaban calibrated anti Xa assays/coagulometer systems with specific or other branch calibrators. METHODS: In 59 samples drawn at trough or peak from patients taking rivaroxaban, plasma levels were measured by HemosIL Liquid anti Xa in ACLTOP 300/500, and STA liquid Anti Xa in TCoag Destiny Plus. HemosIL and STA rivaroxaban calibrators and controls were used. CLSI guideline procedures EP15A3 for precision and trueness, EP6 for linearity, and EP9 for methods comparison were used. RESULTS: Coefficient of variation within run and total precision (CVR and CVWL respectively) of plasmatic rivaroxaban were < 4.2 and < 4.85% and BIAS < 7.4 and < 6.5%, for HemosIL-ACL TOP and STA-Destiny systems, respectively. Linearity verification 8 - 525 ng/mL a Deming regression for methods comparison presented R 0.963, 0.968 and 0.982, with a mean CV 13.3% when using different systems and calibrations. CONCLUSIONS: The analytical performance of plasma rivaroxaban was acceptable in both systems, and results from reagent/coagulometer systems are comparable even when calibrating with different branch material.

[Renal function and plasma dabigatran level measured at trough by diluted thrombin time assay]. / Función renal y nivel plasmático de dabigatrán en el valle, medido por un ensayo de trombina diluida.

Dabigatran etexilate (direct thrombin inhibitor) is effective in preventing embolic stroke in patients with atrial fibrillation. It does not require laboratory control, but given the high renal elimination, its measurement in plasma is important in renal failure. The objectives of the study were to verify the analytical quality of the diluted thrombin time assay for measurement of dabigatran plasma concentration (cc), correlate cc with classic coagulation assays, prothrombin time (PT) and activated partial thromboplastin time (APTT), and evaluate them according to the creatinine clearance (CLCr). Forty plasma samples of patients (34 consecutive and 6 suspected of drug accumulation) receiving dabigatran at 150 (n = 19) or 110 (n = 21) mg/12 hours were collected. Blood samples were drawn at 10-14 hours of the last intake. Dabigatran concentration was determined by diluted thrombin time (HemosIl DTI, Instrumentation Laboratory (IL). PT and APTT (IL) were performed on two fotooptical coagulometers, ACL TOP 300 and 500 (IL). DTI presented intra-assay coefficient of variation < 5.4% and inter-assay < 6%, linearity range 0-493 ng/ml. Patients' cc: median 83 (4-945) ng/ml. Individuals with CLCr in the lowest tertile (22.6-46.1 ml/min) showed significantly higher median cc: 308 (49-945), compared to the average 72 (12-190) and highest tertile, 60 (4-118) ng/ml. Correlation between cc and APTT or PT were moderate, r2 = 0.59 and -0.66, p < 0.0001, respectively. DTI test allowed us to quantify plasma dabigatran levels, both in patients with normal or altered renal function, representing a useful tool in clinical situations such as renal failure, pre surgery or emergencies.

Validation of an Automated Immunoturbidimetric Assay for Fibrinogen/Fibrin Degradation Products Measurement and its Correlation to a Semi-Quantitative Latex Agglutination Test.

BACKGROUND: Laboratory determination of fibrinogen/fibrin degradation product (FDP) levels is important as a hyperfibrinolytic state marker. The aim of the study was to verify the analytical performance of an automated immunoturbidimetric assay (AIMT) for FDP and its comparison to a latex agglutination semiquantitative (SLAT) test. METHODS: Total precision and accuracy was calculated following the EP 15-A2 protocol at two levels of controls. The protocol EP6 was performed for linearity. For semi-quantitative methods comparison, 71 consecutive samples were used. Concordance between methods results in term of positive and negative, and in categories, from <10 to > 160 µg/mL, was calculated through Cohen kappa coefficient (). RESULTS: Total CV%: low control (10.8 µg/mL) 8.0 and 3.7 vs. 4.8 and high control (31.3 µg/mL) 2.7 and 3.8 vs. 3.6, for coagulometer ACL TOP 500 and 300 vs. manufacturer claimed, respectively. Linearity between 0 and 125 µg/mL showed polynomial fit analysis applicable. When correlating AIMT to SLAT, a good concordance was observed:  of results expressed as positive-negative = 79.5% with 90.1% of agreement (p < 0.001), of results expressed as categories = 72.2% (p < 0.001) with 80.3% concordance. CONCLUSIONS: AIMT presented good analytical performance, and the concordance with SLAT by comparison of patients' samples results was also good. The implementation of IMMT in the clinical laboratory is suitable and reliable.

[Levels of antiplatelet factor 4-heparin antibodies and 4T score for heparin induced thrombocytopenia]. / Los niveles de anticuerpos anti factor plaquetario 4-heparina y el índice 4T para trombocitopenia inducida por heparina.

Heparin induced thrombocytopenia (HIT) is an immune-mediated disorder due to antibodies anti platelet factor 4-heparin (HPIA). Thrombocytopenia is often moderate but certain patients can develop morbid thrombotic complications. HPIA detection by ELISA has high sensitivity but low specificity, and low titers (without clinical significance) are frequent. A pretest clinical score (4T's) was developed in order to recognize patients that are at high risk of HIT. The aim of this study was to correlate HPIA levels and the 4T's score of consecutive patients derived to our center. We evaluated 84 patients (35 of them developed thrombosis); the clinical questionnaire was sent along with the sample and was analyzed by an investigator who did not know the patients' characteristics, and 4T's scores were calculated before performing the laboratory tests. HPIA were measured by ELISA (Asserachrom HPIA) that detects IgG, IgM and IgA isotypes, (the only reagent available in our country). 4T's score correlated with HPIA levels (rho spearman 0.472, p < 0.001). Patients with 4T's = 6 had higher absorbance percentages than those with = 5 (67 vs. 39%, p < 0.001), and patients with thrombosis also presented higher titers (59 vs. 39%, p = 0.017) than those who did not develop this complication. In conclusion, high titers of HPIA measured by EIA which detects the 3 isotypes, clearly correlate with 4T's score = 6 and are more frequent in patients who develop thrombosis, just as reported when an IgG specific ELISA is used.

[MANAGEMENT RECOMMENDATIONS FOR DIRECT ORAL ANTICOAGULANTS (DOACs) ANTI Xa AND ANTI IIa]. / RECOMENDACIONES DE MANEJO DE LOS ANTICOAGULANTES ORALES DIRECTOS (DOACS) ANTI Xa Y ANTI IIa.

Direct oral anticoagulants have emerged as the drugs that have changed the management of the antithrombotic treatment in the last 15 years. Their advantages, like a more friendly way of anticoagulation and their lower risk of bleeding, especially in the brain, have positioned these new anticoagulants as the first drug of choice in the two most frequent indications of anticoagulation, atrial fibrillation, and the venous thromboembolic disease. However, not all the patients can receive these agents, not all the direct oral anticoagulants have the same characteristics, and most importantly, not all the diseases with an indication of an anticoagulant drug can be treated with them. Therefore, it is mandatory that all the faculties involved in the management of these drugs must know them in depth, to decide the best treatment for the patient. This position paper, from a group of experts in anticoagulation in Argentina, can help the general practitioner in the daily use of direct oral anticoagulants based on the new evidence and the experience of a wide group of professionals. The way we relate to the anticoagulant treatment has changed in the last years. The doctors who work with them must also do so.

Los anticoagulantes orales directos han surgido como una de las herramientas que ha cambiado el manejo de la enfermedad trombótica en los últimos 15 años. Sus ventajas, desde el punto de vista de la facilidad de uso y menor riesgo de sangrado, especialmente de sangrado cerebral, han posicionado a estos nuevos anticoagulantes como la primera alternativa de tratamiento en las dos indicaciones más frecuentes en que necesitamos estas drogas, la fibrilación auricular y la enfermedad tromboembólica venosa. Sin embargo, no todos los pacientes pueden recibir estos agentes, no todos los anticoagulantes directos tienen las mismas propiedades y fundamentalmente, no todas las enfermedades con indicación de un anticoagulante pueden tratarse con ellos;con lo cual es necesario que todos los profesionales que están involucrados en el manejo de estos medicamentos estén obligados a conocerlos en profundidad, para poder decidir el mejor tratamiento en cada caso particular. Este documento de posición de expertos de diferentes especialidades de Argentina, presenta lineamientos para el uso correcto de los anticoagulantes directos en base a nueva evidencia y a la experiencia de uso de un amplio grupo de profesionales. La forma de relacionarnos con el tratamiento anticoagulante ha cambiado. Los médicos que trabajamos con ellos también debemos hacerlo.

Predictors of recurrence of venous thromboembolic disease after discontinuing of anticoagulation: a prospective cohort study. / Predictores de recurrencia de enfermedad tromboembólica venosa post suspensión de anticoagulación: estudio de cohorte prospectiva.

OBJECTIVE: We aim to evaluate factors associated with the recurrence of thromboembolic episodes among patients with a first episode of venous thromboembolic disease during anticoagulation treatment and at least one year after treatment suspension. METHODS: A prospective cohort of patients with a first episode of deep vein thrombosis confirmed by Doppler ultrasound and initiated anticoagulation treatment. Participants were registered in the Institutional Registry of Thromboembolic Disease between June 2015 and March 2019. Patients with cancer, with permanent inferior vena cava filter implant, and those who refused to participate or did not provide informed consent were excluded. All patients were evaluated within treatment at 30 days and at least one year after the suspension of anticoagulation with a D-dimer study and an ultrasound. All patients were evaluated for recurrence, bleeding (major and minor), and death. RESULTS: A total of 304 patients were recruited during the study period. Seventy-three percent were female, and the median age was 80 years. The rate of recurrence rate during anticoagulation treatment was 5% (N = 16/303; 95% confidence interval: 3 to 8), and 5% during post-suspension follow-up (N = 11/202; 95%CI: 3 to 9). The overall bleeding rate was 13% (N = 39; 95%CI: 9 to 17), and 5% for major bleeding. Patients who recurred had higher basal D-dimer mean, higher neutrophils and monocytes, and a higher prevalence of age-adjusted D-dimer ratio greater than 0.5 before discontinuation. In addition, they more frequently had complete leg involvement by ultrasound and received a shorter treatment. CONCLUSIONS: Although some baseline and pre-suspension parameters had a higher recurrence incidence, statistical significance was not reached, probably due to small statistical power and a short-term follow-up.

OBJETIVO: Evaluar factores asociados a la recurrencia de episodios tromboembólicos en pacientes con un primer evento de enfermedad tromboembólica venosa intra-tratamiento, al año de suspendida la anticoagulación. MÉTODO: Cohorte prospectiva con todos los pacientes consecutivos con un primer episodio de trombosis venosa profunda confirmado por eco Doppler, que iniciaron tratamiento anticoagulante incluidos en el Registro Institucional de Enfermedad Tromboembólica, entre junio de 2015 y marzo de 2019. Se excluyeron los pacientes con cáncer, con implante de filtro de vena cava inferior permanente y quienes se negaron a participar o no entregaron el consentimiento informado. Todos los pacientes fueron evaluados a los 30 días, pre-suspensión de anticoagulación con estudio de dímero D y la realización de una ecografía, y al menos un año de suspendida la anticoagulación. Todos los pacientes fueron evaluados para recurrencia, sangrado (mayor y menor) y muerte. RESULTADOS: Se reclutó a 304 pacientes durante el periodo de estudio. La tasa de recurrencia durante la anticoagulación fue de 5% (N = 16/303; intervalo de confianza 95%: 3 a 8), y durante el seguimiento post suspensión fue también 5% (N = 11/220; 95%: 2 a 9). La tasa de sangrado global fue del 13% (N = 39; 95%: 9 a 17), siendo mayor del 5% para sangrado. Los pacientes que recurrieron tenían una media más elevada de dímero D, neutrófilos, monocitos basales y mayor prevalencia de razón de dímero D ajustada por edad mayor a 0,5 previo a la suspensión. Además, presentaban más afectación de la pierna completa por ecografía y recibieron tratamiento anticoagulante de menor duración. CONCLUSIÓN: Si bien algunos parámetros basales y pre-suspensión dieron valores más altos, no se alcanzó significación estadística, probablemente debido al tamaño muestral y a la baja tasa de recurrencia post suspensión asociada al corto seguimiento.

Guidance from the Scientific and Standardization Committee for lupus anticoagulant/antiphospholipid antibodies of the International Society on Thrombosis and Haemostasis: Update of the guidelines for lupus anticoagulant detection and interpretation.

This guidance focuses on methodological aspects of lupus anticoagulant (LA) testing, as well as interpretation of results for clinicians. The main changes in how to test for LA compared with the International Society on Thrombosis and Haemostasis Scientific and Standardization Committee 2009 guidelines, in the preanalytical phase are more detailed recommendations on how to handle testing in anticoagulated patients, and the timing of testing. Also, routine coagulation tests are advised to obtain more information on the coagulation background of the patient, and when necessary, anti-Xa activity measurement for heparins or specific assays for direct oral anticoagulants should be performed. The three-step procedure with two test systems (diluted Russell's viper venom time and activated partial thromboplastin time [aPTT]) is essentially not changed. Silica remains the preferable activator in the aPTT assays, but ellagic acid is not excluded. We advise simultaneous performance of the mixing and confirmatory step, in each sample with a prolonged screening test. The confirmatory step can also be performed on a mixture of patient plasma and normal pooled plasma. Cutoff values should be established in-house on at least 120 normals, with transference of the manufacturer's cutoffs as an alternative. Reporting of results has not been changed, although more attention is focused on what clinicians should know. Patient selection for LA testing has been expanded.

Nonimmune-acquired factor XIII deficiency: a cause of high volume and delayed postoperative hemorrhage.

: Factor XIII (FXIII) levels may decrease because of surgical consumption. Acquired FXIII deficiency could be a cause of postoperative hemorrhage usually underdiagnosed in clinical practice. To determine the diagnosis confirmation rate of acquired FXIII deficiency in postsurgical patients with clinical suspicion and to compare the characteristics and evolution of patients with or without FXIII deficiency. We performed a retrospective cohort study, which included 49 inpatients who were attended at our university hospital from 2014 to 2018 with suspicion of acquired FXIII deficiency because of disproportionate postoperative hemorrhage. FXIIIA levels less than 50% was considered a deficiency. Persistence of bleeding for more than 48 h, drop in hematocrit points, red blood cells transfused units, hemoglobin levels 12-36 h after bleeding, and time elapsed from the procedure to the bleeding were assessed as outcome variables. Logistic regression was employed for both univariate and multivariate analyses. Of the 49 patients included, 27(55%) had FXIII deficiency, with a median level of 34% [interquartile range (IQR) 19-42]. Abdominal surgery was the most common [n = 21 (43%)]. All patients had routine coagulation tests within the hemostatic range. FXIII deficiency was associated with a drop of more than 4 points in hematocrit [OR 59.69 (95% CI 4.71-755.30)], red blood transfused units >2 [OR 45.38 (95% CI 3.48-590.65)], and delayed bleeding >36 h after surgery [OR 100.90 (95% CI 3.78-2695.40)]. Plasma-derived FXIII concentrate was administered to eight patients with life-threatening bleeding with resolution within 24 h. Only one deficient patient died from bleeding. FXIII levels were measured 15 days after diagnosis or more in 20 out of 27 deficient patients, with normal results. Acquired FXIII deficiency may be a frequent underdiagnosed entity that should be considered when high-volume and delayed postoperative hemorrhage is present in patients with hemostatic routine coagulation test results.

[Argentine Consensus in effective management of anticoagulation clinics for the use of vitamin k antagonists]. / Consenso Argentino en gestión efectiva de clínicas de anticoagulación para el uso de antagonistas de la vitamina k.

Treating an anticoagulated patient with vitamin K antagonists (VKA) remains a challenge, especially in areas where dicoumarins are still the first drug of choice due to the cost of other oral anticoagulants. Anticoagulation clinics have proven to be the most efficient and safe way to avoid thrombotic and hemorrhagic complications and to keep patients in optimal treatment range. However, they require adequate infrastructure and trained personnel to work properly. In this Argentine consensus we propose a series of guidelines for the effective management of the anticoagulation clinics. The goal is to achieve the excellence in both the clinical healthcare and the hemostasis laboratory for the anticoagulated patient. The criteria developed in the document were agreed upon by a large group of expert specialists in hematology and biochemistry from all over the country. The criteria presented here must always be considered when indicating VKA although they had to be adapted to the unequal reality of each center. Taking these premises into consideration will allow us to optimize the management of the anticoagulated patient with VKA and thus minimize thrombotic and hemorrhagic intercurrences, in order to honor our promise not to harm the patient.

El tratamiento de un paciente anticoagulado con antagonistas de la vitamina K (AVK) sigue siendo un desafío, especialmente en regiones donde, por el costo, los dicumarínicos son todavía la alternativa más buscada a la hora de elegir un anticoagulante oral. Las clínicas de anticoagulación han demostrado ser la forma más eficiente y segura de evitar complicaciones trombóticas y hemorrágicas y de mantener al paciente en rango óptimo de tratamiento. Sin embargo, requieren de una adecuada infraestructura y personal capacitado para que funcionen eficientemente. En este consenso argentino se propone una serie de parámetros para la gestión efectiva de una clínica de anticoagulación. El objetivo es lograr una elevada calidad desde el punto de vista clínico-asistencial a través de un laboratorio de hemostasia de excelencia. Los criterios desarrollados en el documento fueron consensuados por un amplio grupo de expertos especialistas en hematología y en bioquímica de todo el país. Estos criterios deben adaptarse a la irregular disponibilidad de recursos de cada centro, pero siempre se los debe tener en cuenta a la hora de indicar el tratamiento anticoagulante con estas drogas. Tener en consideración estas premisas nos permitirá optimizar la atención del enfermo anticoagulado con AVK y de esta forma minimizar las intercurrencias trombóticas y hemorrágicas a las que está expuesto, para así honrar nuestra promesa de no dañar al paciente.

Thrombophilia in human immunodeficiency virus-infected patients with osteonecrosis: Is there a real connection? The first case-control study.

Several reports have described an increased incidence of osteonecrosis in human immunodeficiency virus-infected patients (HIV+), but the cause has not been established. The association between thrombophilia and osteonecrosis in HIV+ was studied. A case-control study in HIV+, 19 cases and 38 controls, was designed. Magnetic resonance imaging was made in both groups to confirm or exclude hip osteonecrosis. The extensive tests of thrombophilia were measured, and the clinical data were recorded, nadir of CD4(+) cell count and well-known risk factors for osteonecrosis. Thrombophilia has been frequently found both in patients with and without osteonecrosis (thrombophilia, 68.4% vs 60.5%), but no specific thrombophilia tests were significantly associated with osteonecrosis. A low nadir of CD4(+) (<60 cells/microL) and corticoid use were significantly (P < .05) associated with osteonecrosis. In multivariate analysis, only nadir of CD4(+) <60 cells/microL remained a predictor of osteonecrosis (odds ratio = 7.33; 95% confidence interval, 1.80-29.82, P = .005). Thrombophilia might have a limited role in the development of osteonecrosis in HIV+. Nadir of CD4(+) <60 cells/microL and corticoid use were main factors.

[Chronic thromboembolic pulmonary hypertension with and without antiphospholipid syndrome]. / Hipertension pulmonar tromboembolica cronica con y sin sindrome antifosfolipido.

UNLABELLED: Chronic thromboembolic pulmonary hypertension (CTE-PH) is defined as the chronic obstruction by organized thrombi in pulmonary artery and their branches causing pulmonary hypertension. The objective is to evaluate features and outcome of CTE-PH in patients with and without coexisting antiphospholipid syndrome (APS). All patients studied at our Institution with CTE-PH between June 1993 and June 2005 were analyzed retrospectively. Sixteen out of 38 patients were APS positive (group A), and 22/38 patients (group B) disclosed normal results (n = 10) or other thrombophilic abnormalities (n =12). RESULTS: both groups were similar in age (mean 41 vs. 50 years), NYHA class at diagnosis (81 vs. 100% in III-IV) and the presence of previous or coexistent thrombosis in other territories (31 vs. 27%). Sixty three percent of patients in group A and 55% of patients in group B underwent thromboendarterectomy. The patients were followed during an average of 45 months (0.5-144). At the end of follow up all the APS patients and all the chirurgical patients were in I-II functional class (p=0.053). The median survival from diagnosis was 59 months for group A and 27 months for group B (p=0.199). The mean survival of patients who underwent thromboendarterectomy was 56 months for group A vs. 33 months for group B (p=0.08). We conclude that patients with CTE-PH and APS disclosed a trend to a better survival than patients with CTE-PH without APS. Those patients with CTE-PH and APS who underwent thromboendarterectomy tended to achieve a better functional class and survival than those who received medical treatment.

Estudio del desempeño analítico del dispositivo portátil microINR en pacientes anticoagulados con acenocumarol / Analytical performance of the microINR portable device in acenocoumarol anticoagulated patients

Resumen La razón internacional normalizada (RIN) se utiliza para controlar a los pacientes anticoagulados con antagonistas de la vitamina K. El objetivo de este estudio fue evaluar el desempeño del nuevo dispositivo portátil microINR, que utiliza tromboplastina recombinante, en pacientes anticoagulados con acenocumarol. Grupo 1: los pacientes proporcionaron muestras de sangre venosa y capilar para realizar pruebas paralelas que permitieron comparar microINR con cinco combinaciones diferentes de reactivo/sistema de detección: tromboplastina de cerebro de conejo con detección nefelométrica, foto-óptica y por viscosidad y tromboplastina humana recombinante con detección nefelométrica y fotoóptica. Todas las tromboplastinas tenían un índice de sensibilidad internacional (ISI) específico de equipo informado por el fabricante menor de 1,10. Grupo 2: los resultados de microINR se compararon con CoaguChek como dispositivo preestablecido. La precisión se evaluó utilizando materiales de control líquidos. El coeficiente de variación del material de control en microINR fue de 6,2%. El análisis de regresión de Passing-Bablok y Bland-Altman mostró un coeficiente de correlación superior a 0,92 y un pequeño sesgo cercano a cero para todas las comparaciones de microINR con cada método tradicional realizado con sangre venosa. Ambos dispositivos portátiles tuvieron un muy buen coeficiente de correlación (r=0,98) y un pequeño sesgo de 0,02. Los resultados muestran un acuerdo clínico del 100% con un grado de concordancia Kappa mayor de 0,63 para todos los métodos tradicionales y de 0,82 para la comparación con Coagu- Chek. De acuerdo a los resultados obtenidos, el microINR es adecuado para el control de pacientes anticoagulados con acenocumarol.

Abstract The international normalised ratio (INR) is used to monitor vitamin K antagonist anticoagulated patients. The aim of this study was to evaluate the performance of the microINR portable device in acenocoumarol anticoagulated patients. Group 1: patients provided capillary and venous blood samples for parallel testing comparing microINR with five different pairs of reagent/clot detection systems: brain rabbit thromboplastin with nephelometric, photooptic and viscocity clot detection and recombinant human thromboplastin with nephelometric and photooptical detection. All thromboplastins have an instrument-specific International Sensitivity Index (ISI) lower than 1.10 reported by the manufacturer. Group 2: microINR results were compared with CoaguChek as an established device. Precision was assessed using liquid control materials. The control material coefficient of variation obtained in microINR device was 6.2%. The Passing-Bablok and Bland-Altman regression analysis showed a correlation coefficient greater than 0.92 and a small bias close to zero for all comparisons of microINR with each traditional coagulation method performed on venous blood samples. Both portable devices had a good correlation (r=0.98) and a very low bias of 0.02. The results show clinical agreement of 100% with a Kappa greater than 0.63 for different traditional INR and greater than 0.83 for CoaguChek. The performance microINR is suitable for the anticoagulation control of patients taking acenocumarol.

Resumo A razão normalizada internacional (INR) é utilizada para monitorar pacientes anticoagulados com antagonistas da vitamina K. O objetivo deste estudo foi avaliar o desempenho do dispositivo portátil microINR, um novo dispositivo que utiliza tromboplastina recombinante, em pacientes anticoagulados com acenocumarol. Grupo 1: os pacientes forneceram amostras de sangue venoso e capilar para testes paralelos que permitiram a comparação do microINR com cinco combinações diferentes de reagente/ sistema de detecção: tromboplastina de cérebro de coelho com detecção nefelométrica, foto-óptica e de viscosidade. Tromboplastina humana recombinante com detecção nefelométrica e foto-óptica. Todas as tromboplastinas tinham o Índice de Sensibilida de Internacional (ISI) específico do kit relatado pelo fabricante inferior a 1,10. Grupo 2: os resultados do microINR foram comparados com o CoaguChek como dispositivo padrão. A precisão foi avaliada usando materiais de controle líquidos. O coeficiente de variação do material de controle em microINR foi de 6,2%. A análise de regressão de Passing-Bablok e Bland-Altman mostrou um coeficiente de correlação maior que 0,92 e um pequeno viés próximo a zero para todas as variáveis. sangue. Ambos os wearables tiveram um coeficiente de correlação muito bom (r=0,98) e um pequeno viés de 0,02. Os resultados mostram 100% de concordância clínica com grau de concordância Kappa maior que 0,63 para todos os métodos tradicionais e 0,82 para a comparação com CoaguChek. De acordo com os resultados obtidos, o microINR é adequado para o controle de pacientes anticoagulados com acenocumarol.

Recomendaciones de manejo de los anticoagulantes orales directos (DOACs) anti Xa y anti IIa / Recommendations for the practical management of the direct oral anticoagulants anti Xa and anti IIa

Resumen Los anticoagulantes orales directos han surgido como una de las herramientas que ha cambiado el manejo de la enfermedad trombótica en los últimos 15 años. Sus ventajas, desde el punto de vista de la facilidad de uso y menor riesgo de sangrado, especialmente de sangrado cerebral, han posicionado a estos nuevos anticoagulantes como la primera alternativa de tratamiento en las dos indicaciones más frecuentes en que necesitamos estas drogas, la fibrilación auricular y la enfermedad tromboembólica venosa. Sin embargo, no todos los pacientes pueden recibir estos agentes, no todos los anticoagulantes directos tienen las mismas pro piedades y fundamentalmente, no todas las enfermedades con indicación de un anticoagulante pueden tratarse con ellos;con lo cual es necesario que todos los profesionales que están involucrados en el manejo de estos medicamentos estén obligados a conocerlos en profundidad, para poder decidir el mejor tratamiento en cada caso particular. Este documento de posición de expertos de diferentes especialidades de Argentina, presenta lineamientos para el uso correcto de los anticoagulantes directos en base a nueva evidencia y a la experiencia de uso de un amplio grupo de profesionales. La forma de relacionarnos con el tratamiento anticoagulante ha cambiado. Los médicos que trabajamos con ellos también debemos hacerlo.

Abstract Direct oral anticoagulants have emerged as the drugs that have changed the man agement of the antithrombotic treatment in the last 15 years. Their advantages, like a more friendly way of anticoagulation and their lower risk of bleeding, especially in the brain, have positioned these new anticoagu lants as the first drug of choice in the two most frequent indications of anticoagulation, atrial fibrillation, and the venous thromboembolic disease. However, not all the patients can receive these agents, not all the direct oral anticoagulants have the same characteristics, and most importantly, not all the diseases with an indication of an anticoagulant drug can be treated with them. Therefore, it is mandatory that all the faculties involved in the management of these drugs must know them in depth, to decide the best treatment for the patient. This position paper, from a group of experts in anticoagulation in Argentina, can help the general practitioner in the daily use of direct oral anticoagulants based on the new evidence and the experience of a wide group of professionals. The way we relate to the anticoagulant treatment has changed in the last years. The doctors who work with them must also do so.

Efecto de las diferentes drogas anticoagulantes sobre el ensayo de fibrinógeno derivado del tiempo de protrombina / Effect of different anticoagulant drugs on the prothrombin time-derived fibrinogen assay

Resumen El objetivo de este trabajo fue comparar los niveles de fibrinógeno (FBG) obtenidos por el método de Clauss con los obtenidos por el método de fibrinógeno derivado del tiempo de protrombina (FBG PT-d), con dos tromboplastinas, en pacientes anticoagulados con distintas drogas. Se estudiaron pacientes anticoagulados consecutivos: 105 con antagonistas de la vitamina K (AVK), 55 con heparina no fraccionada (HNF), 58 con heparina de bajo peso molecular (HBPM), 60 con rivaroxabán, 45 con apixabán, 60 con dabigatrán y 100 controles normales (CN). El FBG se determinó por el método de Clauss y FBG PT-d utilizando tromboplastina de cerebro de conejo o recombinante humana; los niveles de heparina, rivaroxabán y apixabán por método cromogénico anti Xa; el dabigatrán con el ensayo de tiempo de trombina diluido. Existió un sesgo positivo (p<0,001) al comparar el FBG PT-d vs. FBG por Clauss: CN: 13,7%, AVK: 31,8%, rivaroxabán: 34,8% y apixabán: 20,0% cuando se utilizó tromboplastina de conejo. En el caso de las muestras que contenían HBPM se observó este desvío con ambas tromboplastinas. El sesgo porcentual en presencia de dabigatrán y heparina no fraccionada no fue estadísticamente distinto del obtenido en el grupo control. El ensayo de FBG PT-d no debe utilizarse en pacientes anticoagulados con rivaroxabán, apixabán, HBPM o AVK, ya que sobreestima los niveles de FBG. El porcentaje de sesgo depende del tipo de tromboplastina utilizado y fue mayor con la de cerebro de conejo en el sistema de detección utilizado.

Abstract The aim of this study was to compare fibrinogen (FBG) results obtained by Clauss method (FBG-C) and by the prothrombin time-derived fibrinogen assay (FBG PT-d) with two thromboplastins in patients under anticoagulation. Consecutive anticoagulated patients were studied: 105 vitamin-K antagonist (VKA), 55 unfractioned heparin, 58 LMWH, 60 rivaroxaban, 45 apixaban and 60 dabigatran, and 100 healthy controls (NC). FBG-C was performed by Clauss and FIB PT-d with rabbit brain and human recombinant thromboplastins, respectively. Heparins, rivaroxaban and apixaban levels were measured by antiXa; dabigatran by thrombin diluted assay. A positive bias of FBG PT-d vs. FBG-C with both thromboplastins were seen in NC (13.7 and 19.0 % for HS and RP, respectively), but bias with HS in rivaroxaban, apixaban and VKA patients were significantly higher compared to NC: 34.8%, 20.0 % and 31.8 %, respectively. LMWH presented higher BIAS compared to NC with both thromboplastins. Samples with unfraction heparin and dabigatran presented similar bias to NC. FBG PT-d should not be used in patients under anticoagulant treatment because of an important overestimation of FBG could be obtained in these patients. The percentage of bias depends on the type of thromboplastin used; it was higher with rabbit brain thromboplastin in the detection system used.

Resumo O objetivo deste trabalho foi comparar os níveis de fibrinogênio (FBG) obtidos pelo método de Clauss com aqueles obtidos pelo método do fibrinogênio derivado do tempo de protrombina (FBG PT-d), com duas tromboplastinas, em pacientes anticoagulados com diferentes drogas. Pacientes anticoagulados consecutivos foram estudados: 105 com antagonista da vitamina K (AVK); 55 com heparina não fracionada (UFH); 58 com heparina de baixo peso molecular (HBPM), 60 com rivaroxabana, 45 com apixabana, 60 com dabigatrana e 100 controles normais (CN). FBG foi determinado pelo método de Clauss e FBG PT-d usando tromboplastina de cérebro de coelho ou tromboplastina humana recombinante; níveis de heparina, rivaroxabana e apixabana pelo método cromogênico anti-Xa; dabigatrana com ensaio de tempo de trombina diluída. Há um viés positivo (p<0,001) ao comparar o FBG PT-d vs FBG de Clauss: CN: 13,7%; AVK: 31,8%, rivaroxabana: 34,8% e apixabana 20,0% quando foi utilizada tromboplastina de coelho. No caso das amostras contendo HBPM, esse desvio foi observado com ambas as tromboplastinas. O viés percentual na presença de dabigatrana e heparina não fracionada não foi estatisticamente diferente daquela obtida no grupo controle. O ensaio de FBG PT-d não deve ser usado em pacientes anticoagulados com rivaroxabana, apixabana, LMWH ou VKA, pois superestima os níveis de FBG. A porcentagem de viés depende do tipo de tromboplastina utilizado e foi maior com a de cérebro de coelho, no sistema de detecção utilizado.

The emerging role of multiple antiphospholipid antibodies positivity in patients with antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by clinical symptoms of vascular thrombosis and/or pregnancy morbidity in the presence of autoimmune antiphospholipid antibodies (aPL). Current laboratory APS criteria include the presence of at least one of the three relevant aPL: lupus anticoagulant, anticardiolipin antibodies and anti-ß2 glycoprotein I antibodies. Therefore, patients could have a single aPL pattern or combinations of aPL. Evidence arising from clinical experience indicates that patients having the highest aPL titer and simultaneous aPL detected by different tests have a worse prognosis and a higher probability of recurrence of the APS clinical features. In recent years, an emerging role of multiple aPL positivity in the identification of high-risk patients with aPL/APS is evident. This paper will review the current knowledge on the clinical relevance of having single or multiple aPL positivity.

Consenso argentino en gestión efectiva de clínicas de anticoagulación para uso de antagonistas de la vitamina K / Argentine consensus in effective management of anticoagulation clinics for the use of vitamin K antagonists

Resumen El tratamiento de un paciente anticoagulado con antagonistas de la vitamina K (AVK) sigue siendo un desafío, especialmente en regiones donde, por el costo, los dicumarínicos son todavía la alternativa más buscada a la hora de elegir un anticoagulante oral. Las clínicas de anticoagulación han demostrado ser la forma más eficiente y segura de evitar complicaciones trombóticas y hemorrágicas y de mantener al paciente en rango óptimo de tratamiento. Sin embargo, requieren de una adecuada infraestructura y personal capacitado para que funcionen eficientemente. En este consenso argentino se propone una serie de parámetros para la gestión efectiva de una clínica de anticoagulación. El objetivo es lograr una elevada calidad desde el punto de vista clínico-asistencial a través de un laboratorio de hemostasia de excelencia. Los criterios desarrollados en el documento fueron consensuados por un amplio grupo de expertos especialistas en hematología y en bioquímica de todo el país. Estos criterios deben adaptarse a la irregular disponibilidad de recursos de cada centro, pero siempre se los debe tener en cuenta a la hora de indicar el tratamiento anticoagulante con estas drogas. Tener en consideración estas premisas nos permitirá optimizar la atención del enfermo anticoagulado con AVK y de esta forma minimizar las intercurrencias trombóticas y hemorrágicas a las que está expuesto, para así honrar nuestra promesa de no dañar al paciente.

Abstract Treating an anticoagulated patient with vitamin K antagonists (VKA) remains a challenge, especially in areas where dicoumarins are still the first drug of choice due to the cost of other oral anticoagulants. Anticoagulation clinics have proven to be the most efficient and safe way to avoid thrombotic and hemorrhagic complications and to keep patients in optimal treatment range. However, they require adequate infrastructure and trained personnel to work properly. In this Argentine consensus we propose a series of guidelines for the effective management of the anticoagulation clinics. The goal is to achieve the excellence in both the clinical healthcare and the hemostasis laboratory for the anticoagulated patient. The criteria developed in the document were agreed upon by a large group of expert specialists in hematology and biochemistry from all over the country. The criteria presented here must always be considered when indicating VKA although they had to be adapted to the unequal reality of each center. Taking these premises into consideration will allow us to optimize the management of the anticoagulated patient with VKA and thus minimize thrombotic and hemorrhagic intercurrences, in order to honor our promise not to harm the patient.