In a 2004 study at the Kansas University Medical Center, it was found that low-density lipoprotein (LDL) apheresis, a process that separates blood constituents and removes LDL, resulted in significant reductions in whole blood viscosity at all shear rates. It was hypothesized that this procedure would immediately reduce viscosity at all shear rates due to the dramatic reduction of serum cholesterol and particular proteins.
A total of 6 patients, 3 women and 3 men, participated in the study. All 6 patients had cardiovascular disease, LDL cholesterol of >200 mg/dL, and were receiving treatment with lipid-lowering medication. Whole blood viscosity was determined immediately before and after apheresis using an automated scanning capillary viscometer that measures blood viscosity at a complete range of shear rates. Statistically significant reductions for total cholesterol, triglycerides, high-density lipoprotein, very low-density lipoprotein, and LDL were achieved after apheresis, with an overall mean reduction of 62% in LDL cholesterol.
Using blood samples collected immediately before and after apheresis, it was found that LDL apheresis reduced blood viscosity for all shear rates (p < 0.05 for all). The mean viscosity level reduction after apheresis was 21% at a high shear rate (450 seconds-1), and 15% at a low shear rate (11.2 seconds-1). Although high levels of LDL are thought to increase blood viscosity, reduce blood flow, and increase the risk of cardiovascular disease, additional studies are needed to evaluate the relationship between reductions in blood viscosity by LDL apheresis and its effects on vascular disease.