Abnormal rheology in cyanotic congenital heart disease--a factor in non-immune nephropathy

There are few data on non-immune nephropathy in cyanotic congenital heart disease reported in the literature. Rheologic changes have been suspected to be involved in the pathogenesis. This study was performed to describe the characteristics of renal functional and hemorheological abnormalities in a large group of patients with cyanotic congenital heart disease.

Thirty-five cyanotic patients with median oxygen saturation of 82% (range 38-92%), age 18 years (range 5-63 years), and 13 acyanotic controls with atrial septal defect, age 37 years (range 20-66 years) were included. Red cell indices, blood and plasma viscosity were analyzed. Renal function was evaluated with measurements of albumin, alpha1-microglobulin, transferrin, immunoglobuline, and N-acetyl-beta-D-glucosaminidase in the urine.

Fifteen cyanotic patients and 1 control patient had pathologic albuminuria (p < 0.05). In cyanotic patients blood and plasma viscosity, erythrocyte count, hemoglobin, and hematocrit were elevated while mean corpuscular volume and mean corpuscular hemoglobin were decreased (p < 0.05). The possible impact of blood hyperviscosity on proteinuria is indicated by multiple regression analysis (odds ratio = 0.5, confidence intervals 22-130, p < 0.05).

Our study shows a coincidence of elevated blood viscosity and proteinuria in patients with cyanotic congenital heart disease. This observation supports the hypothesis that impaired peritubular capillary blood flow with increased intraglomerular blood pressure may add to chronic glomerular dysfunction.