Enfermedad de von Willebrand adquirida. Aspectos generales Acquired von Willebrand’s disease. General aspects

La enfermedad de von Willebrand adquirida es una enfermedad hemorrágica poco común. Aproximadamente en la mitad de los casos se asocia con enfermedades linfoproliferativas y también se ha relacionado con trastornos mieloproliferativos, neoplasias, enfermedades inmunológicas, cardiovasculares y otras condiciones clínicas. Debe sospecharse en todos los pacientes que presenten una diátesis hemorrágica de aparición tardía sin historia personal o familiar de coagulopatía; los síntomas clínicos son similares a los de la enfermedad de von Willebrand congénita. Esta enfermedad parece tener una etiología multifactorial; en la mayoría de los pacientes afectados el factor von Willebrand (FvW) se sintetiza normalmente, sin embargo, es rápidamente removido del plasma a través de diferentes mecanismos, cuyo resultado final común es la disminución de los niveles circulantes de este factor. Los ensayos clásicos de laboratorio incluyen la exploración de la hemostasia primaria y las pruebas específicas para la determinación de la actividad antigénica y funcional del FvW. El tratamiento va dirigido en 2 direcciones principales: corregir episodios de sangrado agudo y tratar la enfermedad subyacente y condiciones asociadasThe acquired Willebrand’s disease is a rare hemorrhagical disease. Approximately in half of the cases, it is associated with lymphoproliferative diseases and it has been also related to myeloproliferative disorders, neoplasias, immunological and cardiovascular diseases, and other clinical conditions. It must be suspected in all patients presenting a hemorrhagic diathesis of late appearance with no personal or family history of coagulopathy. The clinical symptoms are similar to those of congenital Willebrand’s disease. This disease seems to have a multifactorial ethiology. In most of the affected patients. The von Willebrand factor (vWf) is normally synthesized; however, it is rapidly removed from plasma through different mechanisms, whose final common result is the reduction of the circulating levels of this factor. The clinical laboratory tests include the exploration of primary hemostasia and the specific tests for determining the antigenic and functional activity of vWF. The treatment has 2 main objectives: to correct the acute bleeding episodes and to treat the underlying disease and associated condition

Estado actual del mecanismo de la coagulación sanguínea Present state of the blood coagulation mechanism

Actualmente se acepta de forma categórica que el evento iniciador principal de la coagulación sanguínea es la exposición del factor tisular (FT), lo cual da lugar a la formación del complejo factor VIIa/FT que activa a los factores IX y X en la superficie de las células que expresan el FT, y se forman las primeras cantidades de trombina. Esta trombina ejerce múltiples funciones en el mecanismo hemostático, pero es insuficiente para lograr una hemostasia eficaz, lo cual solo se logra con el ensamblaje del complejo protrombinasa en la superficie plaquetaria. El descubrimiento en la década de los 90 de la activación del factor XI por la trombina, permite explicar las observaciones clínicas en los pacientes con deficiencia de los factores de la fase de contacto de la coagulación: estos no presentan complicaciones hemorrágicas (excepto el déficit de factor XI). El descubrimiento realizado recientemente de la activación de la precalicreína y del factor XI por una cisteín proteasa localizada en la superficie de las células endoteliales fundamentalmente hace sospechar un nuevo papel de estas proteínas in vivo. La coagulación sanguínea es un proceso estrechamente regulado, y por su significación fisiológica es importante la regulación de la vía del factor tisular que limita las cantidades iniciales de trombina, así como la regulación de las proteasas formadas durante el mecanismo de la coagulación por la antitrombina III y de los cofactores activados por el sistema de la proteína CAt present, it is categorically accepted that the exposure of the tissue factor (TF) is the main initiator event of blood coagulation, which brings about the formation of the factor VIIa/TF complex that activates the factors IX and X on the surfaces of the cells expressing the TF and, thus, the first amounts of thrombin are formed. This thrombin has multiple functions in the haemostatic mechanism, but it is insufficient to attain an efficient haemostasis, which is only possible with the assembly of the prothrombinase complex on the platelet surface. The discovery in the 1990’s of the activation of factor XI by thrombin allows to explain the clinical observations made in those patients with deficiency of the coagulation contact phase factors: these patients do not present hemorrhagic complications (excepting the deficit of factor XI). The recent discovery of the activation of precallicrein and factor XI by a cysteine protease located mainly on the surface of the endothelial cells make us think about a new role of these proteins in vivo. Blood coagulation is a closely regulated process and due to its physiological significance it is important the regulation of the tissue factor pathway that limits the initial amounts of thrombin, as well as the regulation of the proteases formed during the mechanism of coagulation by antithrombin III and of the cofactors activated by the protein C syste

Sensibilidad del tiempo parcial de tromboplastina activado a la deficiencia de factores VIII y IX Y a la heparina Sensitivity of the activated partial thromboplastin time to the deficiency of factors VIII and IX and heparin

Se reevaluó el rango de referencia del tiempo parcial de tromboplastina activada (TPTA). Se obtuvo un rango de referencia de 29 a 40 seg. con una media (<img width=13 height=15 id="_x0000_i1026" src=x.gif>) de 34,01 seg. Con nuestro sistema de reactivos se alcanzaron resultados aceptables en cuanto a la sensibilidad a diferentes niveles de actividad de los factores VIII y IX, se logró una alta correlación en ambos casos (r2 = 0,9842 y 0,9846, respectivamente) cuando se relacionó el TPTa con los diferentes niveles de actividad de los factores VIII y IX. Se obtuvo una respuesta lineal en el intervalo de actividad de heparina utilizado normalmente en la terapia (0,2 a 0,5 UI/mL) y se alcanó una buena respuesta a altas concentraciones de heparina (0,8 UI/mL), expresada por un valor finito del TPTa. Se corroboró la necesidad de alargar el tiempo de incubación con el activador a 10 min para mejorar la sensibilidad del ensayo a la heparina<br>The reference range of the activated partial thromboplastin time (APTT) was reevaluated. A reference range from 29 to 40 seconds with a mean (<img border=0 width=13 height=15 id="_x0000_i1033" src=x.gif>) of 34.01 sec. was obtained. By using our system of reagents, acceptable results were obtained as regards the sensitivity to different levels of activity of factors VIII and IX. A high correlation was attained in both cases (r2 = 0.9842 and 0.9846, respectively) when the APTT was associated with the different levels of activity of factors VIII and IX. A linear response was obtained in the interval of heparin activity commonly used in therapy (0.2 to 0.5 UI/mL) and a good response was attained at high concentrations of heparin (0.8 UI/mL) expressed by a finite value of APTT. The need to extend the incubation time with the activator to 10 min. to improve the sensitivity of the test to heparin was corroborate

Anticoagulante lúpico en enfermedades autoinmunes Lupus anticoagulant in autoimmune diseases

El tromboembolismo venoso es una complicación reconocida en diferentes enfermedades autoinmunes. Se ha establecido que la detección del anticoagulante lúpico (AL) y posiblemente los anticuerpos anticardiolipina (AAC) tipo Ig G en título alto y medio, ayuden a identificar pacientes con riesgo de trombosis. Estudiamos el AL en 81 pacientes con enfermedades autoinmunes: 25 pacientes con lupus eritematoso sistémico (LES), 28 pacientes con púrpura trombocitopénica idiopática (PTI), 15 con anemia hemolítica autoinmune (AHAI) y 13 que se incluyeron en el grupo de otras enfermedades, que comprendían vasculitis cutánea de pequeños vasos, enfermedad mixta del tejido conectivo, artritis reumatoidea y esclerodermia. El AL se encontró en el 19,7 % del total de los estudiados: 16 % en pacientes con LES, 21,4 % en pacientes con PTI y 40 % en la AHAI. En el grupo de otras enfermedades no se halló ningún paciente con el AL positivo. El 56,3 % de los pacientes con AL positivo presentaron alguna manifestación atribuible al síndrome antifosfolípido (SAF)Venous thromboembolism is a well-known complication in different autoimmune diseases. It has been established that detection of lupus anticoagulant (LA) and possibly IgG type anticardiolipin antibodies (AAC) in high and medium titers help to identify patients with thrombosis risk. We studied LA in 81 patients with autoimmune erythomatous lupus, 28 patients with idiopathic thrombocytopenic purpura, 15 with autoimmune hemolytic anemia and 13 patients who were included in the group covering other diseases such as small vessel skin vasculitis, combined disease of the connective tissue, rheumatoid arthritis and sclerodermia. LA was found in 19,7 % of the total number of cases, in 16% of patients with LES, 21,4 % of those with ITP and 40 % of cases with AIHA. In the group of other diseases, there was no patient with positive LA. 56,3 % of patients with positive AL showed some manifestations related to antiphospholipid syndrom

Descripción de un inmunoensayo enzimático que reconoce anticuerpos anti-factor VIII/von Willebrand obtenidos a partir de hibridomas múridos Description of an enzime immunoassay that recognizes anti-factor VIII/von Willebrand antibodies obtained from murine hybridomas

Se describe un inmunoensayo enzimático (ELISA) que detecta anticuerpos anti-Factor-VIII/von Willebrand (FVIII/vW), con una relación de enlace > 5, que permite reconocer dichos anticuerpos tempranamente en los cultivos de hibridomas múridos. Para la adsorción de las placas del inmunoensayo se utilizaron preparados semipurificados de FVIII/vW obtenidos en Cuba. Se inmunizaron ratones Balb/c con la finalidad de generar los anticuerpos monoclonales detectados por este ELISA. Se obtuvo un clon con crecimiento estable y varios subclones positivos por el ELISA con actividad biológica específica de anticuerpos inhibidores de FVIII<br>An enzime immunoassay (ELISA) that detects anti-Factor VIII/von Willebrand (FVIII/vw) antibodies with a binding relationship > 5 that allows the early recognition of such antibodies in the cultures of murine hybridomas is described. Semipurified preparations of FVIII/vw obtained in Cuba were used for the adsorption of the immunoassay plates. Balb/c mice were immunized in order to generate the monoclonal antibodies detected by this ELISA. A clone with stable growth and several positive subclones were obtained by ELISA with specific biological activity of FVIII-inhibiting antibodie

Efecto agregante plaquetario de 2 citolisinas: Sti y Stii purificadas de la anémona marina Stichodactyla Helianthus Platelet aggregating effect of 2 cytolysins: StI and StII purified from the sea anemone Stichodactyla helianthus

Las citolisinas Sticholysina I (St I) y Sticholysina II (St II) inducen la agregación plaquetaria en el plasma rico en plaquetas en el rango de concentraciones ensayadas (0,5 a 10 µg/mL). Para ambas citolisinas se obtienen porcentajes de agregación plaquetaria superiores al 90 % con menos del 50 % de lisis celular. La agregación plaquetaria se mantiene elevada aún cuando la lisis celular disminuye a menos del 20 %. El EDTA 2 mM/L y el verapamilo 100 mM/L inhiben significativamente la agregación inducida por StI, lo que evidencia que el calcio extracelular tiene una función importante en este proceso y probablemente esta citolisina tiene una función similar a la de un ionóforo de calcio. Con StII no se obtuvo inhibición significativa de la agregación en presencia de EDTA y verapamilo. La agregación inducida por ambas citolisinas no está influida por el aumento del AMPc intracelular y es independiente de la formación de tromboxano A2 en la plaquetaCytolysing Sticholysina I (St I) and Sticholysina II (St II) induce platelet aggregation in the plasma rich in platelets in the range of assayed concentrations (0.5 to 10 m g/mL). Percentages of platelet aggregation over 90 % with less than 50 % of cellular lysis were obtained for both cytolysins. The platelet aggregation is high even when the cellular lysis decreases to less than 20 %. EDTA 2 mM/L and verapamyl 100 mM/L significantly inhibit the aggregation induced by StI, which shows that extracellular calcium has an important function in this process and that probably this cytolysin plays a role similar to that of a calcium ionophore. With StII there was no significant inhibition of the aggregation in the presence of EDTA and verapamyl. The aggregation induced by both cytolysins is not influenced by the increase of intracellular AMPc and it is independent of the formation of thromboxane A2 in the platele

Post-anaesthesia pulmonary complications after use of muscle relaxants (POPULAR): a multicentre, prospective observational study

Background Results from retrospective studies suggest that use of neuromuscular blocking agents during general anaesthesia might be linked to postoperative pulmonary complications. We therefore aimed to assess whether the use of neuromuscular blocking agents is associated with postoperative pulmonary complications. Methods We did a multicentre, prospective observational cohort study. Patients were recruited from 211 hospitals in 28 European countries. We included patients (aged ≥18 years) who received general anaesthesia for any in-hospital procedure except cardiac surgery. Patient characteristics, surgical and anaesthetic details, and chart review at discharge were prospectively collected over 2 weeks. Additionally, each patient underwent postoperative physical examination within 3 days of surgery to check for adverse pulmonary events. The study outcome was the incidence of postoperative pulmonary complications from the end of surgery up to postoperative day 28. Logistic regression analyses were adjusted for surgical factors and patients’ preoperative physical status, providing adjusted odds ratios (ORadj) and adjusted absolute risk reduction (ARRadj). This study is registered with ClinicalTrials.gov, number NCT01865513. Findings Between June 16, 2014, and April 29, 2015, data from 22803 patients were collected. The use of neuromuscular blocking agents was associated with an increased incidence of postoperative pulmonary complications in patients who had undergone general anaesthesia (1658 [7·6%] of 21694); ORadj 1·86, 95% CI 1·53–2·26; ARRadj –4·4%, 95% CI –5·5 to –3·2). Only 2·3% of high-risk surgical patients and those with adverse respiratory profiles were anaesthetised without neuromuscular blocking agents. The use of neuromuscular monitoring (ORadj 1·31, 95% CI 1·15–1·49; ARRadj –2·6%, 95% CI –3·9 to –1·4) and the administration of reversal agents (1·23, 1·07–1·41; –1·9%, –3·2 to –0·7) were not associated with a decreased risk of postoperative pulmonary complications. Neither the choice of sugammadex instead of neostigmine for reversal (ORadj 1·03, 95% CI 0·85–1·25; ARRadj –0·3%, 95% CI –2·4 to 1·5) nor extubation at a train-of-four ratio of 0·9 or more (1·03, 0·82–1·31; –0·4%, –3·5 to 2·2) was associated with better pulmonary outcomes. Interpretation We showed that the use of neuromuscular blocking drugs in general anaesthesia is associated with an increased risk of postoperative pulmonary complications. Anaesthetists must balance the potential benefits of neuromuscular blockade against the increased risk of postoperative pulmonary complications