Sickle-cell Anemia and Latent Diastolic Dysfunction: Echocardiographic Alterations

Introduction

Sickle-cell anemia (SCA) is a disease that can cause systemic complications, such as multiple organ dysfunction due to vaso-occlusion and endothelial activation. The genetic cause of the disease is a substitution of the amino acid glutamic acid for valine in the position 6 of the beta globin chain. Stress factors in the vascular microenvironment (cellular dehydration, hypoxemia, increased corpuscular hemoglobin concentration, decreased red blood cell transit time in the microcirculation, and decreased blood pH) trigger intracellular hemoglobin polymerization, forming paracrystalline structures that cause sickling of erythrocytes and increased blood viscosity, hemolysis, and vaso-occlusion^,. Simultaneously, free hemoglobin in the plasma sequesters nitric oxide (NO), leading to decreased NO bioavailability and increased endothelial adhesion (in physiological conditions, NO inhibits of platelet aggregation, platelet activation, transcription of platelet adhesion proteins).

The increase in cardiac output (CO), the afterload reduction due to the peripheral vasodilation as a response to hypoxemia, the increase in blood viscosity secondary to the morphological alterations, and the loss of the deformability of the sickle red blood cells are factors involved with the systolic ventricular overload and progressive enlargement of the cardiac chambers^–.

[…]