Pulmonary Hypertension in Sickle Cell Disease: Current Controversies and Clinical Practices

Sickle cell disease (SCD), the most common genetic disorder worldwide, affects up to 100,000 people living in the United States and accounts for up to 300,000 births annually worldwide. A hemoglobinopathy characterized by recurrent episodes of hemolysis and vaso-occlusion, SCD adversely affects nearly every vascular bed of the systemic and pulmonary vasculature. The two primary pathogenic mechanisms of SCD are vaso-occlusion and hemolysis, with downstream effects on inflammation, redox biology, nitric oxide (NO) metabolism, and coagulation. The hallmark of vaso-occlusion in SCD is abnormal interactions between erythrocytes, leukocytes, platelets, and the vascular endothelium leading to promotion of inflammation, thrombosis, and oxidative stress [1, 2].