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 9.9years (±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] >25mmHg.

Results: We found that, mean±SD serum P-selectin level (platelet activator marker) was significantly higher in thalassemic patients (2337±566pg/ml) in comparison to controls (1467±247pg/ml) (P<0.001). Mean serum protein-C and antithrombin-III levels were significantly lower in thalassemic patients (1.2±1.3µg/ml, 27.3±7.5mg/dl) in comparison to controls (2.3±1.3µg/ml, 35.1±4.1mg/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.

Keywords: Hypercoagulable state; Platelet activation; Pulmonary hypertension; Thalassemia; Thromboembolism.