Study of platelet activation, hypercoagulable state, and the association with pulmonary hypertension in children with β-thalassemia

Abstract

Background: The increased survival rate of thalassemic patients has led to unmasking of management related complications which were infrequently encountered. Objective: Study the increased coagulation and platelet activation in children with β-thalassemia, to analyze the factors that lead to such hypercoagulable state and to study pulmonary hypertension (PH) in conjunction with platelet activation and hypercoagulable state in children with β-thalassemia. Methods: 36 Egyptian children with β-thalassemia with a mean age of 9.9 years (±4.7 SD). In addition, 20 healthy Egyptian children matched for age and sex were enrolled as a control group. Both were subjected to clinical and laboratory assessments. Echocardiography was done to the patient group and PH was diagnosed based on calculated mean pulmonary artery pressure [MPAP] >25 mmHg. Results: We found that, mean ± SD serum P-selectin level (platelet activator marker) was significantly higher in thalassemic patients (2337 ± 566 pg/ml) in comparison to controls (1467 ± 247 pg/ml) (P < 0.001). Mean serum protein-C and antithrombin-III levels were significantly lower in thalassemic patients (1.2 ± 1.3 µg/ml, 27.3 ± 7.5 mg/dl) in comparison to controls (2.3 ± 1.3 µg/ml, 35.1 ± 4.1 mg/dl) (P = 0.003 and <0.001) respectively. PH was detected in 17 (47.2%) patients and it was significantly associated with splenectomy (P = 0.01) and non-transfusion dependent thalassemia (NTDT) (P = 0.04). PH was positively correlated with serum levels of P-selectin (r = 0.38, P = 0.02), fibrinogen (r = 0.41, P = 0.01) and negatively correlated with serum protein-C level (r = −0.48, P = 0.003). Conclusion: A chronic hypercoagulable state and platelet activation is present in children with β-thalassemia. Splenectomy and transfusion infrequency are the main risk factors noted to be associated with such hypercoagulable state and platelet activation and consequently the PH among our thalassemic patients.