Platelet yield and recovery following the PRGF-U1 protocol in a peruvian population

Objective: to determine the platelet recovery and yield of the PRGF-U1 protocol in a peruvian population. methods: an observational, descriptive and cross-sectional study was conducted with a simple random probability sample of 32 patients who attended the laboratorio Scalab in Trujillo, Peru. a blood sample was taken from each patient in order to obtain the concentration of platelets and before and after the PRGF-U1 protocol, in order to determine platelet recovery and yield. to compare basal platelet concentrations and platelet recovery and yield with gender and age, the chi-square test, student's t-distribution and pearson's correlation coefficient were used considering a significance level of p<0.05. results: platelet yield was less than 2.2 in two patients and greater than or equal to 2.2 in 30 patients; platelet recovery was equal to 0.4 in 30 patients and greater than 0.4 in two patients. a statistically significant relationship (p<0.05) between basal platelet count and age was found when comparing basal platelet count, platelet recovery and platelet yield according to gender and age, but no significant relationship between the other variables (p>0.05). conclusion: the PRGF-U1 protocol presents optimal platelet yield and minimal expected platelet recovery.

Is preoperative clopidogrel resistance a predictor of bleeding and risks in patients undergoing emergency cabg surgery?

Abstract Objective: The aims of this study were to determine whether the detection of preoperative clopidogrel resistance in patients undergoing cardiac surgery while using clopidogrel could play a guiding role in the prediction of postoperative excessive bleeding, transfusion requirements, and risks and to provide clinically significant data. Methods: Two hundred and twenty-two patients [median age: 59.4 (38-83) years; 38 females] undergoing emergency and elective coronary artery bypass graft (CABG) surgeries in our clinic were evaluated prospectively. Patients with multiple systemic diseases, other than diabetes mellitus (DM) and hypertension (HT), were excluded. Patients receiving clopidogrel were also evaluated for clopidogrel resistance and grouped according to the results of this test. Assessments of platelet functions were performed by multiplate impedance aggregometry method and adenosine diphosphate test. Results: The use of postoperative fresh blood replacement and platelet transfusion was higher in patients receiving clopidogrel than in those not receiving it (P=0.001, P=0.018). DM, HT, myocardial infarction, and the number of presentation to the emergency room were significantly higher in patients receiving clopidogrel than in those not receiving it (P<0.05). No significant difference was determined between patients with and without clopidogrel resistance regarding the amount of bleeding during and after surgery, erythrocyte suspension and fresh-frozen plasma transfusion rates, preoperative troponin values, ejection fraction values, and length of hospital stays (P>0.05). Conclusion: We think that resistance studies in patients receiving clopidogrel before cardiac surgery are not efficient to predict bleeding and bleeding-related complications in patients undergoing emergency and elective CABG surgeries.

The role of point-of-care assessment of platelet function in predicting postoperative bleeding and transfusion requirements after coronary artery bypass grafting.

Objective: Objective platelet function assessment after cardiac surgery can predict postoperative blood loss, guide transfusion requirements and discriminate the need for surgical re‑exploration. We conducted this study to assess the predictive value of point‑of‑care testing platelet function using the Multiplate® device. Methods: Patients undergoing isolated coronary artery bypass grafting were prospectively recruited (n = 84). Group A (n = 42) patients were on anti‑platelet therapy until surgery; patients in Group B (n = 42) stopped anti‑platelet treatment at least 5 days preoperatively. Multiplate® and thromboelastography (TEG) tests were performed in the perioperative period. Primary end‑point was excessive bleeding (>2.5 ml/kg/h) within first 3 h postoperative. Secondary end‑points included transfusion requirements, re‑exploration rates, intensive care unit and in‑hospital stays. Results: Patients in Group A had excessive bleeding (59% vs. 33%, P = 0.02), higher re‑exploration rates (14% vs. 0%, P < 0.01) and higher rate of blood (41% vs. 14%, P < 0.01) and platelet (14% vs. 2%, P = 0.05) transfusions. On multivariate analysis, preoperative platelet function testing was the most significant predictor of excessive bleeding (odds ratio [OR]: 2.3, P = 0.08), need for blood (OR: 5.5, P < 0.01) and platelet transfusion (OR: 15.1, P < 0.01). Postoperative “ASPI test” best predicted the need for transfusion (sensitivity ‑ 0.86) and excessive blood loss (sensitivity ‑ 0.81). TEG results did not correlate well with any of these outcome measures. Conclusions: Peri‑operative platelet functional assessment with Multiplate® was the strongest predictor for bleeding and transfusion requirements in patients on anti‑platelet therapy until the time of surgery. Study registration: ISRCTN43298975 (http:// www.controlled‑trials.com/ISRCTN43298975/).

Alta reatividade plaquetária durante tratamento é preditora de eventos cardíacos em pacientes com stents farmacológicos / High on-treatment platelet reactivity predicts cardiac events in patients with drug-eluting stents

FUNDAMENTO: O papel dos testes de reatividade plaquetária (RP) na predição de eventos em longo prazo em pacientes latino-americanos tratados com stents farmacológicos (SF) não foi estabelecido. OBJETIVOS: Analisar o papel dos testes de RP na predição de eventos após a implantação de SF. MÉTODOS: De maio de 2006 a janeiro de 2008, foram incluídos 209 pacientes brasileiros que se submeteram a tratamento eletivo com SF. A RP foi avaliada 12 a 18 horas após o procedimento, por agregometria de transmitância de luz com 5µM de ADP. Os pacientes foram acompanhados prospectivamente por até 4,8 anos. Dezessete (8%) dos indivíduos foram perdidos durante o acompanhamento e a coorte final foi composta de 192 pacientes. A curva ROC foi utilizada para determinar o melhor ponto de corte de 5µM de ADP para prever eventos. O endpoint primário foi uma combinação de morte cardiovascular, infarto agudo do miocárdio, trombose definitiva de stent, e revascularização de artéria alvo.Modelos de risco proporcional de Cox foram utilizados para determinar as variáveis independentemente associadas com o tempo até o primeiro evento. RESULTADOS: O melhor ponto de corte de 5µM de ADP foi de 33%. Cento e sete (55,7%) pacientes apresentaram 5mM de ADP > 33%. A taxa de sobrevivência livre de eventos em 1.800 dias foi de 55% contra 70% para os indivíduos com ADP5 acima e abaixo desse ponto de corte, respectivamente (p = 0,001). Preditores de tempo independentes para o primeiro evento foram tabagismo atual (HR 3,49, IC95%: 1,76-6,9, p = 0,0003), ADP 5mM > 33% (HR 1,95, IC95%: 1,09-3,51, p = 0,025) e idade (HR 1,03 IC 95%: 1,0-1,06, p = 0,041). CONCLUSÕES: Neste estudo, 55,7% dos pacientes apresentaram alta reatividade plaquetária durante tratamento. 5µM de ADP > 33% foi um preditor independente de eventos em longo prazo.

BACKGROUND: The role of platelet reactivity (PR) tests in the prediction of long-term events in Latin-American patients treated with drug-eluting stents (DES) has not been established. OBJECTIVES: To assess the role of PR tests in the prediction of events after DES implantation. METHODS: From May 2006 through January 2008, 209 Brazilian patients who underwent elective treatment with DES were included. PR was assessed 12 to 18h after the procedure by light transmittance aggregometry with 5µM of ADP. Patients were prospectively followed for up to 4.8 years. Seventeen (8%) individuals were lost to follow-up and the final cohort comprised 192 patients. Receiver operating curve (ROC) was used to determine the best 5µM of ADP cutoff to predict events. The primary endpoint was a combination of cardiovascular death, acute myocardial infarction, definite stent thrombosis, and target-artery revascularization. Cox proportional hazard models were used to determine the variables independently associated with the time to the first event. RESULTS: The best ADP 5µM cutoff was 33%. One hundred and seven (55.7%) patients had ADP 5µM >33%. Event-free survival rate at 1,800 days was 55% vs. 70% for individuals with ADP5 above and below such cutoff, respectively (p=0.001). Independent predictors of time to first event were current smoking (HR 3.49; 95% CI 1.76-6.9; p=0.0003), ADP 5µM >33% (HR 1.95; 95% CI 1.09-3.51; p=0.025) and age (HR 1.03; 95% CI 1.0-1.06; p=0.041). CONCLUSIONS: In this study, 55.7% of the patients had high on-treatment platelet reactivity. ADP 5µM >33% was an independent predictor of long-term events.

Antiagregantes plaquetários e testes de função plaquetária na era dos stents coronarios / Antiplatelet therapy and platelet reactivity tests in the era of coronary stents

Em pacientes portadores de stents coronarianos é obrigatória a utilização de dupla antiagregação plaquetária com ácido acetilsalicílico e clopidogrel. Umnúmero considerável de pacientes portadores de stents em uso de clopidogrel apresenta alta reatividadeplaquetária, caracterizando uma resposta deficiente a esse fármaco. Esses pacientes apresentam risco maiselevado não apenas de trombose de stents, mas também de morte cardiovascular, infarto agudo do miocárdio e reestenose intra-stent. Dobrar a dose de manutenção doclopidogrel não se mostrou uma estratégia eficaz. A utilização de drogas mais potentes, como prasugrel eticagrelor parece ser uma estratégia válida, principalmente no contexto de síndrome coronariana aguda, mas não hátrabalhos confirmando os benefícios em pacientes estáveis. Nos pacientes crônicos em uso de clopidogrel, não há recomendações na literatura para realização de rotina dos testes de função plaquetária, mas esses podemser realizados em casos selecionados.

El síndrome de las plaquetas pegajosas y su diagnóstico en el laboratorio / The sticky platelet syndrome and its diagnosis in the laboratory

El síndrome de las plaquetas pegajosas (SPP) es un trastorno plaquetario autosómico dominante considerado como una de las causas más frecuentes de eventos trombóticos, tanto arteriales como venosos. Este síndrome supone trastornos en la agregación de las plaquetas caracterizados por su incremento anormal. El mecanismo patogénico no se conoce; su existencia puede determinarse con las pruebas de agregación y adhesión plaquetarias. Tampoco se conoce su prevalencia, pero hay datos que sugieren que es frecuente. Algunos investigadores plantean que es responsable del 23 por ciento de las trombosis arteriales inexplicables y del 14 por ciento de las venosas, en las que no es posible identificar una causa. Se presenta una breve revisión acerca de la información disponible sobre el síndrome de las plaquetas pegajosas y su trascendencia en la salud. En Cuba existen pocos reportes de la evaluación clínica de pacientes con esta afección, por lo que resulta necesario realizar estudios más profundos para establecer la magnitud de la enfermedad

The sticky platelet syndrome (SPS) is an autosomal dominant platelet disorder considered as one of the most common causes of thrombotic events, both arterial and venous. This syndrome involves disturbances in platelet aggregation characterized by abnormal increase. The pathogenic mechanism is not known. Its existence can be determined by platelet aggregation and platelet adhesion tests. Its prevalence is also unknown, but evidence suggests that it is common. Some researchers argue that it is responsible for 23 percent of unexplained arterial thrombosis and 14 percent of the vein thrombosis, in which is not possible to identify a cause. Here a brief review on the available information on the sticky platelet syndrome and its importance in health is shown. In Cuba there are few reports of the clinical evaluation of patients with this condition, so further study to determine the extent of the disease is needed

Avaliação de diferentes metodologias laboratoriais para detecção de aloanticorpos plaquetários. Determinação da prevalência e importância clínica destes aloanticorpos em pacientes transfundidos / Evaluation of different laboratorial methodologies for the detection of platelet alloantibodies. Prevalence determination and clinical importance of these alloantibodies in transfused patients

A aloimunização contra antígenos plaquetários é um dos grandes desafios no tratamento de pacientes refratários à transfusão de plaquetas. OBJETIVOS: avaliar o desempenho de metodologias mais utilizadas em laboratórios de referência internacional para a pesquisa de anticorpos plaquetários (PAP); verificar a prevalência destes anticorpos na nossa população; avaliar se as transfusões estão causando aloimunização, e se estes aloanticorpos apresentam importância clínica. MATERIAIS E MÉTODOS: foram testadas amostras PRÉ e PÓS transfusionais em três grupos de pacientes sendo grupo 1 com patologias onco-hematológicas, grupo 2 com patologias não tumorais e grupo 3 composto dos mesmos tipos de pacientes do grupo 2 mas que não receberam transfusão (grupo controle). Numa primeira fase foi realizado estudo retrospectivo com amostras de soro congeladas no período de 1996 a 2001. A segunda fase consistiu em estudo prospectivo com amostras coletadas dos pacientes durante sua internação, no período de 2004 a 2006. Quatro diferentes metodologias foram testadas: imunofluorescência indireta por citometria de fluxo (PIFT), imobilização de antígenos plaquetários utilizando anticorpos monoclonais (MAIPA), teste de microlinfocitotoxicidade (LCT) e uma nova metodologia, conhecida como FLOW PRA N. Na fase 1 foram analisados 87 pacientes, e na fase 2, 96 pacientes, separados nos três grupos respectivamente. Na segunda fase do estudo, foi realizado o incremento da contagem corrigida de plaquetas (ICCp) para todos os pacientes que receberam transfusão de plaquetás. Para esta avaliação um novo grupo de pacientes (n=40) foi adicionado ao estudo, devido ao pequeno número encontrado na segunda fase. RESULTADOS: -as metodologias testadas apresentaram diferenças nas freqüências dos anticorpos detectados, porém as inefodologias MAIPA, PIFT e FLOW ´PRAPOT.TM´ foram as mais concordantes entre si...

Evaluation of some platelet functions and platelet membrane glycoproteins in uremic, hemodialysis and renal transplant patients

The hemostatic defect of chronic renal failure [CRF] is well recognized. Increased bleeding has been attributed to platelet dysfunction. However, the available reports are controversial. To study platelet aggregation and glycoprotein receptors' [GP] expression in a well identified population with CRF. 25 patients with advanced CRF on conservative treatment [CRF group], 25 patients on regular hemodialysis [HD group], 25 renal transplant patients [Tx group], and 20 age-, race- and sex-matched healthy controls [control group] were subjected to complete physical examination, complete blood count, bleeding time [BT], renal functional parameters and other necessary laboratory tests, in addition to estimation of platelet aggregation in response to adenosine 5-diphosphate [ADP] and ristocetin as well as GPIb, GPIIb, and GPIIIa receptors' expression using fluorescein isothiocyanate-conjugated monoclonal antibodies CD42b, CD41 and CD62, respectively and a flow cytometer. BT was prolonged in both CRF and HD groups [P<0.001], and was not attributed to a decrease in platelet count. Both CRF and HD patients had similar, but significantly decreased maximum percentage of platelet aggregation induced by either ADP or ristocetin compared with Tx and healthy control groups [P<0.001]. GPIb expression was significantly decreased in the CRF group than the Tx and healthy control groups [P<0.05], while HD group showed non significant difference when compared with CRF, Tx or control groups. GPIIb and GPIIIa showed a highly significant decreased expression in both CRF and HD groups compared with Tx and healthy control groups [P<0.001], with no significant difference in between both uremic groups. An inverse correlation was observed between serum creatinine and GPIIb [r=-0.641, P=0.023] and GPIIIa [r=-0.545, P=0.031] receptors' expression in CRF patients versus no correlation in HD patients. The results of the studied parameters in Tx group were comparable to healthy controls. Uremic patients have decreased platelet aggregability and decreased GP receptors' expression [mainly GPIIb and GPIIIa], denoting that platelet dysfunction is at least partially contributing to their hemorrhagic problem. The observed defects were not corrected by regular HD. Renal transplantation seemed to be a better choice

La citometría de flujo en el estudio de las plaquetas / Flow cytometry in the study of platelets

En la década de los 60 comenzó a desarrollarse la técnica de citometría de flujo, pero los primeros trabajos basados en esta técnica aplicados al estudio de las plaquetas, aparecieron a finales de la década de los 80 del siglo pasado. Los ensayos de citometría de flujo complementan e incluso pueden remplazar los estudios convencionales de función plaquetaria. Se describen las ventajas y limitaciones del método, así como los antígenos plaquetarios que más se han empleado como marcadores de activación plaquetaria. El valor diagnóstico del método ha sido bien establecido en el estudio de defectos genéticos, de los síndromes protrombóticos que involucran activación plaquetaria, trombopoyesis, terapia antitrombótica, estudios de trombocitopenias alo y autoinmunes, así como la activación plaquetaria en otras situaciones clínicas como el infarto agudo de miocardio y la angina inestable. La incorporación de la citometría de flujo al estudio de las plaquetas ha tenido una importante repercusión no solo en el diagnóstico, sino también en la fisiopatología de un grupo de enfermedades relacionadas con el comportamiento plaquetario

Programa de controle da qualidade externo em hematologia: variações interlaboratoriais para eritrograma e plaquetas em Curitiba e Região Metropolitana, PR / External quality control program in hematology: interlaboratory variability for red blood cell and platelets values in Curitiba and Metropolitan Area, PR, Brazil

A padronização e o controle de qualidade representam elementos imprescindíveis para a rotina laboratorial. Este projeto teve como objetivo analisar a variabilidade interlaboratorial, a partir da distribuição de amostras preservadas para os valores de eritrograma e contagem de plaquetas. Foram preparadas amostras estáveis para eritrograma e contagem de plaquetas a partir de unidades de sangue venoso de 3 doadores, coletadas no Banco de Sangue do Hospital de Clínicas da UFPR. Os eritrócitos e as plaquetas foram isolados e ressuspensos em meio CE após fixação parcial com glutaraldeído (leonart et al. Rev. Brasil. Anal. Clin. 21: 111, 1989; Emendorfer et al Rev. Bras. Anal. Clin. 32: 191, 2000), para amostras controle altas, médias e baixas. Distribuiu-se alíquotas a 14 Laboratórios de Análises Clínicas de Curitiba e Região Metropolitana, que determinaram que os valores do eritrograma e plaquetas, semanalmente, empregando os equipamentos T890 e STKS (Coulter), Cell Dyn 1400,1700 e 3500 (Abbott) ou Sysmex (Roche). Verificou-se o desempenho dos laboratórios por meio dos gráficos de controle de qualidade, determinando-se a frequência de resultados de fora dos limites controle. Observou-se menor ocorrência desses limites para os laboratórios que realizavam controle de qualidade externo e interno, e uma correlação aceitável entre os resultados obtidos com os equipamentos empregados. Tais resultados incentivam a utilização de sistemas de qualidade para assegurar a padronização das técnicas e garantir o controle de qualidade nos Laboratórios e Análises Clínicas.

Alteración de la función plaquetaria / Platelet dysfunction

Las alteraciones de la coagulación en otorrinolaringología son un tema de fundamental importancia, dadas las características de los pacientes de esta especialidad y de las cirugías que se realizan. Estas tienden a sangrar profusamente y no se puede con frecuencia realizar procedimientos hemostáticos. Por esto es de suma importancia conocer las alteraciones existentes. Sobre todo aquellas que son menos frecuentes y por tanto más desconocidas entre los especialistas

Validación clínica de la adhesividad plaquetaria al vidrio por el método de Hellem modificado / Clinical validation of Hellem modified method by glass platelets adhesivity

Se realizó la validación clínica de la determinación de la adhesividad de las plaquetas (AP) al vidrio por el método de Hellem modificado (MHM) sobre una muestra constituida por 30 sujetos sanos, de ambos sexos y edades comprendidas entre 20 y 55 años. dadas las características de este experimento, la determinación se efectuó extrayendo sangre de los brazos izquierdo y derecho, consoderando que ambas detrminaciones son alícuotas aleatorias del tejido sanguíneo de los individuos de la muestra. Adicionalmente se midió en los mismos individuos la tensión arterial, sistólica y diastólica, en ambos brazos. Del análisis de los resultados obtenidos se deduce que: para el grupo de sujetos considerados no hay diferencias significativas en la AP entre muestras tomadas en ambos brazos; la adhesividad porcentual tiene una distribución normal, las adhesividades no están correlacionadas con las correspondientes tensiones sistólicas y diastólicas, y en relación a los valores de la tensión arterial sistólica, los mismos muestran que existen diferencias significativas entre ambos brazos. Las diferencias intraindividuo, en valor absoluto, son importantes (un tercio de las mismas son mayores que el 20 por ciento de AP). Por otra parte el rango de valores obtenidos para la AP en la muestra de individuos estudiada fue del 2 al 80 por ciento. Las amplitudes de las diferencias y del rango de valores de AP en sujetos sanos señalan que la sensibilidad clínica del método es pobre. Este defecto, junto a los inconvenientes operativos, hacen que se discrepe con otros autores sobre la utilidad de emplear el MHM para medir la AP

Study of the possible effect of some calcium channel blockers on platelet functions and blood fibrinolytic activity in the rabbit

Thirty rabbits were used in this study to determine and compare the possible effects of repeated oral daily administration for four weeks of some calcium channel blockers; namely, verapamil [10 mg/kg], perhexiline [10 mg/kg], diltiazem [10 mg/kg], and nifedipine [10 mg/kg] on platelet count and aggregation and on fibrinolytic activity as measured by euglobin clot lysis time [ECLT], plasma platelet factor 4 [antiheparin], concentration and prothrombin, coagulation time. The results indicated that each of verapamil and perhexiline exhibited significant increased tendency to fibrinolysis. On the other hand, diltiazem or nifedipine did not implement such results. Results may indicate that verapamil or perhexiline should be used cautiously in cardiovascular or hematological disorders

Assessment of platelet functions and lipid profile in hypertension

Blood platelets play an important role in the pathogenesis of essential hypertension and hyperlipidemia is a common finding in hypertensive patients. To verify this, 30 male subjects were selected; 10 as a control group with their mean age [51.4 +/- 4.03], they are free from any disease, and 20 recently discovered male patients with essential hypertension with their mean age [52.2 +/- 4.26] years. All subjects were subjected to the following: Full history and meticulous examination, lipid profile study and platelet function tests. The results showed that there is a highly significant increase in platelet functions [aggregation, adhesiveness and platelet factor-3] in hypertensive patients compared to control subjects. A highly significant increase in the levels of total serum lipids, triglycerides, total serum cholesterol and low density lipoprotein, but a highly significant decrease in the level of high density lipoprotein cholesterol when compared to the normotensive control group. Also, there is a significant positive correlation between blood pressure levels, and markers of platelet activity indicating that platelet activity plays a role in the pathogenesis of hypertension and atherosclerosis. The results also showed a positive correlation between blood pressure level and triglycerides and also between platelet aggregation and triglycerides and low density lipoprotein cholesterol. Such a positive correlation between platelet markers and atherogenic LDL-cholesterol may be of pathogenic importance for atherogenesis in hypertension

Platelet function and diabetes mellitus

Platelet aggregation was found to be enhanced in diabetic patients, who did not show any clinical evidence of diabetic vascular disease. This increase was shown with all the four aggregating agents, that is, ADP, epinephrine, collagen and arachidonic acid. Platelet aggregation was enhanced in diabetic patients with clinically apparent diabetic vascular disease. We did not find any difference between the Platelet aggregation of diabetic patients with and without diabetic vascular complications. The aggregation pattern was found to be similar in all the diabetic groups with all four aggregating agents. No significant difference was found between intensity of aggregation, rate of aggregation and lag phase when different concentrations of the aggregating agents were used

Testes de agregaçäo plaquetária: novo parâmetro na avaliaçäo de hemostasia, metodologia e interpretaçäo com revisäo de 198 casos / Plateled aggregation tests: new parameter in the hemostasis evaluation, methodology and interpretation with review of 198 cases

Uma das fases da coagulaçäo inclui a aderência plaquetária à formaçäo vascular, durante a formaçäo do plug hemostático. A formaçäo de trombos envolve um mecanismo similar. A elucidaçäo das alteraçöes plaquetárias, de formas discóides näo adesivas para partículas adesivas, permitiu o desenvolvimento de técnicas para testar o aspecto funcional das plaquetas. Uma destas técnicas é o estudo in vitro da resposta plaquetária a uma série de agentes estimuladores. Testes de agregaçäo plaquetária (TAP) säo indicados na detecçäo de anormalidades funcionais plaquetárias hereditárias ou adquiridas. Discute-se a indicaçäo, metodologia e análise dos TAP, propondo-se fluxogramas para indicaçäo e interpretaçäo clínica dos resultados, baseados em dados da literatura e revisäo de 198 casos

El laboratorio en el estudio de la función plaquetaria / The laboratory in the study of platelet function

Se describen diversas pruebas de laboratorio que son de utilidad en el estudio de la función plaquetaria. Se consideran su técnica e interpretación