TY - JOUR
T1 - Blood Viscosity and its Relationship to Iron Deficiency, Symptoms, and Exercise Capacity in Adults With Cyanotic Congenital Heart Disease
AU - Broberg, Craig S.
AU - Bax, Bridget E.
AU - Okonko, Darlington O.
AU - Rampling, Michael W.
AU - Bayne, Stephanie
AU - Harries, Carl
AU - Davidson, Simon J.
AU - Uebing, Anselm
AU - Khan, Arif Anis
AU - Thein, Swee
AU - Gibbs, J. Simon R.
AU - Burman, John
AU - Gatzoulis, Michael A.
N1 - Funding Information:
This study was funded by a grant from the Royal Brompton Hospital Clinical Research Committee.
PY - 2006/7/18
Y1 - 2006/7/18
N2 - Objectives: This study sought to determine the relationship between blood viscosity and iron deficiency and their impact on symptoms and exercise function in adults with cyanotic congenital heart disease. Background: Iron deficiency is believed to raise whole blood viscosity in cyanotic congenital heart disease, although available data are inconsistent. Methods: Thirty-nine cyanotic adults were prospectively assessed for iron deficiency (transferrin saturation ≤5%), hyperviscosity symptoms, and exercise capacity. Same-day measurement of whole blood viscosity and hematocrit (Hct) adjusted viscosity (cells resuspended in autologous plasma to Hct of 45%) was performed at shear rates ranging from 0.277 s-1 to 128.5 s-1. Results: Viscosity did not differ between patients with iron deficiency (n = 14) and those without (n = 25). Whole blood viscosity correlated with Hct (r = 0.63, p < 0.001 at low shear and r = 0.84, p < 0.001 at high shear) but not with red blood cell size or iron indices. Hyperviscosity symptoms were independent of iron indices but directly correlated with increased Hct-adjusted viscosity (r = 0.41, p = 0.01). Exercise capacity did not differ in iron-deficient patients. However, peak oxygen consumption was higher in those with Hct ≥ 65% (12.6 ± 3.4 ml/kg/m2 vs. 9.8 ± 2.6 ml/kg/m2, mean ± SD, p = 0.036) despite higher whole blood viscosity in these same individuals (p < 0.01 for all shear rates). Conclusions: Iron deficiency is common in cyanotic adults but does not alter viscosity. Hyperviscosity symptoms are associated with a higher Hct-adjusted viscosity independent of cell size or iron stores. Higher Hct is associated with better exercise capacity. Further work to understand the origin of hyperviscosity symptoms is warranted.
AB - Objectives: This study sought to determine the relationship between blood viscosity and iron deficiency and their impact on symptoms and exercise function in adults with cyanotic congenital heart disease. Background: Iron deficiency is believed to raise whole blood viscosity in cyanotic congenital heart disease, although available data are inconsistent. Methods: Thirty-nine cyanotic adults were prospectively assessed for iron deficiency (transferrin saturation ≤5%), hyperviscosity symptoms, and exercise capacity. Same-day measurement of whole blood viscosity and hematocrit (Hct) adjusted viscosity (cells resuspended in autologous plasma to Hct of 45%) was performed at shear rates ranging from 0.277 s-1 to 128.5 s-1. Results: Viscosity did not differ between patients with iron deficiency (n = 14) and those without (n = 25). Whole blood viscosity correlated with Hct (r = 0.63, p < 0.001 at low shear and r = 0.84, p < 0.001 at high shear) but not with red blood cell size or iron indices. Hyperviscosity symptoms were independent of iron indices but directly correlated with increased Hct-adjusted viscosity (r = 0.41, p = 0.01). Exercise capacity did not differ in iron-deficient patients. However, peak oxygen consumption was higher in those with Hct ≥ 65% (12.6 ± 3.4 ml/kg/m2 vs. 9.8 ± 2.6 ml/kg/m2, mean ± SD, p = 0.036) despite higher whole blood viscosity in these same individuals (p < 0.01 for all shear rates). Conclusions: Iron deficiency is common in cyanotic adults but does not alter viscosity. Hyperviscosity symptoms are associated with a higher Hct-adjusted viscosity independent of cell size or iron stores. Higher Hct is associated with better exercise capacity. Further work to understand the origin of hyperviscosity symptoms is warranted.
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U2 - 10.1016/j.jacc.2006.03.040
DO - 10.1016/j.jacc.2006.03.040
M3 - Article
C2 - 16843187
AN - SCOPUS:33745727983
SN - 0735-1097
VL - 48
SP - 356
EP - 365
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology
IS - 2
ER -