Pulmonary Hypertension: An Emerging Risk in Hemoglobin Disorders

Pulmonary hypertension (PH) is one of the main cardiovascular complications in haemoglobinopathies and is considerably implicated in patients’ morbidity and mortality. In thalassemia intermedia, PH is found in about 60% of traditionally managed patients and represents the main cause of heart failure. In sickle cell anemia, PH is encountered in one third of patients and has been found to be a strong and independent predictor of mortality, while in sickle thalassemia, PH is generally less frequent and severe. The pathophysiology of PH in haemoglobinopathies is multifactorial and several mechanisms seem to be implicated, including a complex vasculopathy, hypercoagulability and elastic tissue defects, all associated with chronic hemolysis, high output state due to chronic anemia, as well as left heart dysfunction, pulmonary disorders and thromboembolic complications. Echocardiography is the most useful tool for patients’ screening on a regular basis, while the diagnosis of PH should always be confirmed by right cardiac catheterization. The proper management of the disease itself with haematological modalities such as blood transfusions combined with iron chelation or hydroxyurea, is the most effective approach for the prevention and treatment of haemoglobinopathy-associated PH. Antithrombotic agents should also be considered while the value of novel agents used in the treatment of pulmonary arterial hypertension, including endothelin antagonists or phosphodiesterase-5 inhibitors, is not yet established in patients with haemoglobinopathies.