Aspirin Resistance in Children with Congenital Heart Disease and Its Relationship with Laboratory and Clinical Parameters

Background: Patients with congenital heart disease (CHD) are more prone to thromboembolism. Aspirin is the most commonly used medication around the world to prevent thrombosis in cardiovascular diseases. Objectives: This study aimed to define the frequency of aspirin resistance in pediatric patients with CHD and to evaluate the correlation of clinical and laboratory parameters with aspirin resistance. Methods: The study population consisted of 103 patients using aspirin, including 53 cases of cyanotic CHD and 50 cases of non-cyanotic CHD. Platelet aggregation was measured by the AggreGuide A-100 ADP Assay. Results: The prevalence of aspirin resistance was 36.9% in children with CHD. Although aspirin resistance in cyanotic CHD patients (41.5%) was higher than in non-cyanotic patients (32%), the difference was not statistically significant (P = 0.414). There was no significant association between aspirin responsiveness or resistance and the patient’s sex, age, duration of aspirin use, and concomitant medication use. Comparison of the laboratory data of aspirin-responsive and -resistant patients showed no significant difference between these groups, except for albumin (P = 0.032) and serum fibrinogen (P = 0.0001) levels. The fibrinogen level and thromboembolism history were independent risk factors for aspirin resistance. Also, there was a significant correlation between platelet aggregation in peripheral blood smears and aspirin resistance (P = 0.0001). Conclusions: Our findings suggest that measurement of the serum fibrinogen level and platelet aggregation in blood smears may be the first step to predict aspirin resistance.