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Abstract(s)
As doenças cardiovasculares representam uma importante causa de mortalidade e morbilidade precoce no mundo inteiro. O papel da antiagregação plaquetar tem tido uma importância clínica crescente no tratamento destes pacientes e a sua actividade e o seu uso tem sido alvo de várias pesquisas. O efeito farmacológico das classes de antiagregantes plaquetares caracteriza-se por, mediante o seu mecanismo de acção, produzirem um efeito na fisiologia da hemostase primária, com consequências clínicas que são conhecidas, mas a correlação do efeito laboratorial com o efeito terapêutico ainda é objecto de investigação. O estudo da agregação plaquetar, inserido no estudo mais global da hemostase primária, é hoje efectuado através de diversos métodos laboratoriais, alguns dos quais introduzidos na prática clínica corrente.
O objectivo do presente trabalho é descrever os principais métodos laboratoriais aplicados na avaliação da actividade dos antiagregantes plaquetares, com principal atenção sobre a técnica Platelet Function Analyser (PFA-100) e investigar a sua potencial correlação com a clínica e terapêutica.
Seguiu-se com a metodologia de revisão sistemática de literatura. São descritos os métodos de Agregometria, Tromboelastometria, VerifyNow Assay® (Rapid Platelet Function Analyser - RPFA) e Platelet Function Analyser® (PFA-100) [Siemens]. Discutiu-se os resultados obtidos por testes PFA-100 de amostras sob o efeito de diversos antiagregantes plaquetares e discutiu-se a sua potencial utilização em situações clínicas.
Conclui-se que a técnica PFA-100 é útil na monitorização do tratamento com os inibidores da glicoproteína IIb/IIIa, mostrando diferenças na fase de recuperação dos diferentes agentes. Relativamente aos inibidores P2Y12, vários estudos evidenciaram o uso limitado da técnica PFA-100 na sua monitorização. Em contraste, alguns estudos mostraram a utilidade do teste para estudo de um subconjunto de pacientes com AVC, tratados com clopidogrel e para prever resultados adversos em doentes, após intervenção percutânea nos membros inferiores. Verificou-se um sinergismo nos efeitos antiagregantes plaquetares do ácido acetilsalicílico e do clopidogrel, quando usados em conjunto. O teste tem sido, igualmente, amplamente usado para detectar resistências ao ácido acetilsalicílico e correlacionar este facto com futuros eventos adversos nos doentes. Assim, a técnica PFA-100 torna-se um método promissor no estudo da antiagregação plaquetar mas ainda são necessários mais estudos para permitir concluir a sua utilidade em situações clínicas.
Cardiovascular diseases are a major cause of premature mortality and morbidity worldwide. Antiplatelet therapy has a growing role in the treatment of these patients and their a ctivity and their use have been the subject of several studies. Different classes of platelet inhibitors are characterized by their mechanism of action, produce an effect on the physiology of primary hemostasis, with known clinical results. The correlation between laboratory effect and therapeutic result is still subject to research. The study of platelet aggregation, inserted in the study of global primary hemostasis, can be done by various laboratory methods, some of which are introduced in current clinical practice. The purpose of this paper is to describe the laboratory methods more frequently used in the assessment of antiplatelet activity, a focus on Platelet Function Analyzer technique (PFA-100) and to investigate its potential therapeutic correlation. The methodology followed was a systematic review of literature. The methods described are Aggregometry, Thromboelastography, VerifyNow Assay® (Rapid Platelet Function Analyzer - RPFA) and Platelet Function Analyzer® (PFA-100) [Siemens]. Studies of PFA-100 in different clinical settings are reviewed. It was concluded that the technique PFA-100 is useful in monitoring the treatment with the inhibitors of glycoprotein IIb / IIIa, showing differences in the recovery phase of the different drugs. For the P2Y12 inhibitors, several studies have found little effect on PFA-100 monitoring. Some studies have shown that the PFA-100 is useful to study a subset of stroke patients treated with clopidogrel and for predicting adverse outcomes in patients following percutaneous interventions of the lower limbs. There was a synergism in the effects of antiplatelet with acetylsalicylic acid and clopidogrel, when used together. The test has been also used to detect resistance to acetylsalicylic acid and correlating this with future clinical events in patients. Thus, the technique PFA-100 becomes a promising method to study antiplatelet therapy but more studies are needed to conclude their usefulness in clinical situations.
Cardiovascular diseases are a major cause of premature mortality and morbidity worldwide. Antiplatelet therapy has a growing role in the treatment of these patients and their a ctivity and their use have been the subject of several studies. Different classes of platelet inhibitors are characterized by their mechanism of action, produce an effect on the physiology of primary hemostasis, with known clinical results. The correlation between laboratory effect and therapeutic result is still subject to research. The study of platelet aggregation, inserted in the study of global primary hemostasis, can be done by various laboratory methods, some of which are introduced in current clinical practice. The purpose of this paper is to describe the laboratory methods more frequently used in the assessment of antiplatelet activity, a focus on Platelet Function Analyzer technique (PFA-100) and to investigate its potential therapeutic correlation. The methodology followed was a systematic review of literature. The methods described are Aggregometry, Thromboelastography, VerifyNow Assay® (Rapid Platelet Function Analyzer - RPFA) and Platelet Function Analyzer® (PFA-100) [Siemens]. Studies of PFA-100 in different clinical settings are reviewed. It was concluded that the technique PFA-100 is useful in monitoring the treatment with the inhibitors of glycoprotein IIb / IIIa, showing differences in the recovery phase of the different drugs. For the P2Y12 inhibitors, several studies have found little effect on PFA-100 monitoring. Some studies have shown that the PFA-100 is useful to study a subset of stroke patients treated with clopidogrel and for predicting adverse outcomes in patients following percutaneous interventions of the lower limbs. There was a synergism in the effects of antiplatelet with acetylsalicylic acid and clopidogrel, when used together. The test has been also used to detect resistance to acetylsalicylic acid and correlating this with future clinical events in patients. Thus, the technique PFA-100 becomes a promising method to study antiplatelet therapy but more studies are needed to conclude their usefulness in clinical situations.
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Keywords
Doenças cardiovasculares Inibidores da agregação plaquetar Trombose coronária Enfarte cerebral Doenças cerebrovasculares Homeostase primária - Plaquetas Aterotrombose - Plaquetas
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Universidade da Beira Interior