Chapters authored
Pulmonary Hypertension in Thalassemia Patients
Pulmonary hypertension (PH) is defined in children as a mean pulmonary arterial pressure (PAP) greater than 25 mmHg at rest or 30 mmHg during physical activity, with increased pulmonary artery capillary wedge pressure and an increased pulmonary vascular resistance greater than 3 Wood units × M2. it is the main cause of morbidity and mortality in the group of thalassemia, if no treatment leads to right ventricular heart failure and death. The development of pulmonary arterial hypertension (PAH) is assumed to be the result of many multifactorial pathogenic mechanisms including chronic hemolysis, iron overload, hypercoagulability, and erythrocyte dysfunction as a result of splenectomy, inflammation and nitric oxide (NO) depletion. PAH symptoms are non-specific, their signs consist of right ventricular lift, an accentuated pulmonary component of the second heart sound, a (gallop rhythm) right ventricular third heart sound, and parasternal heave meaning a hypertrophied right ventricle. The diagnosis of PAH requires a clinical suspicion based on symptoms and physical examination. Echocardiography is frequently used to screen for PAH, monitor progression over time and allow identification of patients for whom diagnostic right heart catheterization (RHC) is warranted and its treatment includes hemoglobinopathy specific treatment and PAH specific therapy.
Part of the book: Blood
Portal Vein Thrombosis in Patients with β-Thalassemia
Beta (β)-thalassemia major, a chronic inherited hematological disease, leads to chronic anemia in affected children. One of the options for treatment is splenectomy. However, this treatment involves risk of many complications, one of which is portal vein thrombosis (PVT). The risk factors include exposure of phosphatidyl-serine of abnormal red blood cells (RBCs), increased activation, aggregation and a number of platelets and nucleated RBCs after splenectomy, increased endothelial activation, decreased nitric oxide, organ dysfunction, and thrombophilia. PVT is either complete or partial obstruction and has fatal complications, especially after splenectomy and late diagnosis without effective treatment. Diagnosis is typically made with X-ray. Generally, the incidence of PVT is between 1.7% and 9.2%. Initially, it is asymptomatic; symptoms appear gradually as thrombosis progresses. The easiest way to differentiate it from other conditions is via imaging study like Doppler ultrasound. It is usually associated with prolonged prothrombin time (PT). D-dimer and alkaline phosphatase are generally high. The treatment is the same for both the acute and chronic forms and includes the treatment of causal factors, prevention of thrombus extension, and achievement of patency of the portal vein via regular RBC transfusion and antithrombotic agents.
Part of the book: The Erythrocyte