RESUMO
INTRODUCTION: Platelets play a role in the pathophysiology of venous thromboembolism (VTE). Some studies have not found an association between VTE and platelet aggregation. The PFA-100® analyser is an in vitro assay for assessing primary haemostasis. But, there are no studies to evaluate its association with VTE. We investigated the contribution of the global platelet function and aggregation in the development of VTE. MATERIAL AND METHODS: We analysed 800 individuals who were included in the RETROVE Study (Riesgo de Enfermedad TROmboembólica VEnosa). Global platelet function was evaluated as closure times (CT) with the agonists ADP and epinephrine using a PFA-100® analyser. Platelet aggregation was evaluated by Multiplate™ analyser. The VTE risk for all the parameters was calculated by unconditional logistic regression analyses considering the potential confounders: age, gender, body mass index (BMI), factor VIII (FVIII), the von Willebrand factor (vWF) and the ABO blood group system. RESULTS: The unadjusted odds ratio (OR) values ≤10th percentile for the PFAadp and PFAepi were 4.02 (95% CI, 2.76-5.95) and 3.33 (2.27-4.97). Also, after adjusting for vWF, we obtained lower OR for the PFAadp and for PFAepi: 2.24 (1.44-3.49) and 1.63 (1.04-2.59). But, the whole blood aggregation parameters did not shown an association with VTE risk. CONCLUSION: We demonstrated an association between short CT and VTE risk. Although, the whole blood aggregation parameters did not show an association with the VTE risk. This striking contrast suggests that there are other platelet function mechanisms (e.g. adhesion) that are responsible of VTE risk.
Assuntos
Agregação Plaquetária , Testes de Função Plaquetária/métodos , Tromboembolia Venosa/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Coagulação Sanguínea , Plaquetas/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Tromboembolia Venosa/sangue , Tromboembolia Venosa/etiologia , Tromboembolia Venosa/patologiaRESUMO
OBJECTIVE: To analyze the value of early resting myocardial perfusion gated-SPECT in patients with chest pain and non-diagnostic ECG in the emergency department. PATIENTS AND METHOD: 222 patients (49% women, mean age 61 [13] years) with atypical chest pain and with non-diagnostic ECG were randomized into two groups. Group A comprised 111 patients in whom early resting myocardial perfusion gated-SPECT (<6 hours since the end of chest pain) was performed and CK-MB mass and troponin I were determined at 0, 4 and 8 hours. Group B comprised 111 patients with conventional management in the emergency department without gated-SPECT. RESULTS: Myocardial perfusion gated-SPECT was positive in all 8 patients with increased levels of CK-MB mass and troponin I. This corresponded to a sensitivity and a negative predictive value of 100% for the diagnosis of AMI. Specificity was 84% and positive predictive value was 33% when doubtful results were considered as negative. The number of patients admitted (18.4% vs 32.7%, P<.027) and length of stay (13 [6] hours vs 15.9 [8.6] hours, P<.009) in the emergency department were lower in group A. CONCLUSIONS: In patients with atypical chest pain and non-diagnostic ECG in the emergency department, early resting gated-SPECT was highly sensitive and showed good negative predictive value for the diagnosis of AMI, but positive predictive value was low. This technique may reduce the number of hospitalized patients and length of stay in the emergency department.
