title: Elevated Low-Shear Blood Viscosity is Associated with Decreased Pulmonary Blood Flow in Children with Univentricular Heart Defects.
abstract: After the Fontan procedure, patients with univentricular hearts can experience long-term complications due to chronic low-shear non-pulsatile pulmonary blood flow. We sought to evaluate hemorheology and its relationship to hemodynamics in children with univentricular hearts. We hypothesized that low-shear blood viscosity and red blood cell (RBC) aggregation would be associated with increased pulmonary vascular resistance (PVR) and decreased pulmonary blood flow (PBF). We performed a cross-sectional analysis of 62 children undergoing cardiac catheterization-20 with isolated atrial septal defect (ASD), 22 status post Glenn procedure (Glenn), and 20 status post Fontan procedure (Fontan). Shear-dependent blood viscosity, RBC aggregation and deformability, complete blood count, coagulation panel, metabolic panel, fibrinogen, and erythrocyte sedimentation rate were measured. PVR and PBF were calculated using the Fick equation. Group differences were analyzed by ANOVA and correlations by linear regression. Blood viscosity at all shear rates was higher in Glenn and Fontan, partially due to normocytic anemia in ASD. RBC aggregation and deformability were similar between all groups. Low-shear viscosity negatively correlated with PBF in Glenn and Fontan only (R (2) = 0.27, p < 0.001); it also negatively correlated with pulmonary artery pressure in Glenn (R (2) = 0.15, p = 0.01), and positively correlated with PVR in Fontan (R (2) = 0.28, p = 0.02). Our data demonstrate that elevated low-shear blood viscosity is associated with negative hemodynamic perturbations in a passive univentricular pulmonary circulation, but not in a pulsatile biventricular pulmonary circulation.
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, 4650 Sunset Blvd., Mailstop #34, Los Angeles, CA, 90036, USA. acheng@chla.usc.edu.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Cheng
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, 4650 Sunset Blvd., Mailstop #34, Los Angeles, CA, 90036, USA.
authors.forename: Cheryl M
authors.initials: CM
authors.lastname: Takao
authors.affiliation: Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors.forename: Rosalinda B
authors.initials: RB
authors.lastname: Wenby
authors.affiliation: Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors.forename: Herbert J
authors.initials: HJ
authors.lastname: Meiselman
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, 4650 Sunset Blvd., Mailstop #34, Los Angeles, CA, 90036, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Wood
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, 4650 Sunset Blvd., Mailstop #34, Los Angeles, CA, 90036, USA.|Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors.forename: Jon A
authors.initials: JA
authors.lastname: Detterich
mesh_terms: D000293:Adolescent; D001809:Blood Viscosity; D006328:Cardiac Catheterization / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D018729:Fontan Procedure / Q000009:adverse effects*; D006330:Heart Defects, Congenital / Q000601:surgery*; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D016014:Linear Models; D008297:Male; D011652:Pulmonary Circulation; D016896:Treatment Outcome
keywords: Congenital heart disease; Fontan; Pulmonary vascular resistance; Rheology; Univentricular heart