Avaliação da agregação plaquetária e dosagem do fibrinogênio em pacientes com doenças cardiovasculares e sua correlação com o uso de aspirina e fatores de risco coronariano Evaluation of platelet aggregation and level of fibrinogen in patients with cardiovascular diseases and the correlation of taking aspirin with coronary risk factors Abstract Objective: To evaluate aspirin resistance in patients with cardiovascular diseases and to compare the amount of serum fibrinogen in patients taking aspirin with those who do not. To correlate the platelet aggregation and serum fibrinogen to cardiovascular risk parameters.Method: Eighty-two patients were divided into two groups: Group 1 -41 patients who took 100mg aspirin daily and Group 2 -41 patients who did not utilize platelet antiaggregates. Epidemiological data were collected including age, gender and information on smoking and alcohol intake and serum fibrinogen and platelet aggregation were measured.Results: In the groups analyzed, advanced age (p=0.011), smoking (p=0.009) and alcoholism (p=0.007) were directly associated to the serum fibrinogen level. There were no correlations between smoking, alcoholism, serum fibrinogen and platelet aggregation values (p>0.05). In Group 1, 29% of the patients presented with aspirin resistance. Of these, smokers (p=0.029) and alcoholics (p=0.033) had higher serum fibrinogen levels. Conclusion: Aspirin resistance was present in a high number of patients. Moreover, advanced age, smoking and alcoholism had a direct influence on the serum fibrinogen levels.