Journal Article

Decreased erythrocyte aggregation in Glenn and Fontan: univentricular circulation as a rheologic disease model

Badran, Sarah, Meiselman, Herbert J., Coates, Thomas D., Liu, Honglei, Wenby, Rosalinda, Denton, Christopher, Cheng, Andrew L., Patel, Neil, Wood, John C., Detterich, Jon A., Suriany, Silvie

2024

Overview

Background In the Fontan palliation for single ventricle heart disease (SVHD), pulmonary blood flow is non-pulsatile/passive, low velocity, and low shear, making viscous power loss a critical determinant of cardiac output. The rheologic properties of blood in SVHD patients are essential for understanding and modulating their limited cardiac output and they have not been systematically studied. We hypothesize that viscosity is decreased in single ventricle circulation. Methods We evaluated whole blood viscosity, red blood cell (RBC) aggregation, and RBC deformability to evaluate changes in healthy children and SVHD patients. We altered suspending media to understand cellular and plasma differences contributing to rheologic differences. Results Whole blood viscosity was similar between SVHD and healthy at their native hematocrits, while viscosity was lower at equivalent hematocrits for SVHD patients. RBC deformability is increased, and RBC aggregation is decreased in SVHD patients. Suspending SVHD RBCs in healthy plasma resulted in increased RBC aggregation and suspending healthy RBCs in SVHD plasma resulted in lower RBC aggregation. Conclusions Hematocrit corrected blood viscosity is lower in SVHD vs. healthy due to decreased RBC aggregation and higher RBC deformability, a viscous adaptation of blood in patients whose cardiac output is dependent on minimizing viscous power loss. Impact Patients with single ventricle circulation have decreased red blood cell aggregation and increased red blood cell deformability, both of which result in a decrease in blood viscosity across a large shear rate range. Since the unique Fontan circulation has very low-shear and low velocity flow in the pulmonary arteries, blood viscosity plays an increased role in vascular resistance, therefore this work is the first to describe a novel mechanism to target pulmonary vascular resistance as a modifiable risk factor. This is a novel, modifiable risk factor in this patient population.

• Publisher: Nature Publishing Group US,Nature Publishing Group
• Subject: Adolescent / Blood / Blood tests / Blood Viscosity / Cardiac Output / Child / Child, Preschool / Clinical Research Article / Erythrocyte Aggregation / Erythrocyte Deformability / Erythrocytes / Female / Fontan Procedure / Heart Defects, Congenital - physiopathology / Heart Defects, Congenital - surgery / Heart Ventricles - abnormalities / Heart Ventricles - physiopathology / Hematocrit / Humans / Male / Medicine / Medicine & Public Health / Pediatric Surgery / Pediatrics / Pulmonary arteries / Rheology / Univentricular Heart - physiopathology / Univentricular Heart - surgery / Velocity / Viscosity