Insights provided by the hemorheologic–hemodynamic theory

The hemorheologic-hemodynamic theory explains the significant remaining risk of adverse cardiovascular events in patients with established coronary artery disease despite aggressive lowering of LDL-cholesterol using high dose statin therapy. Such therapy does not address the adverse consequences of arterial stiffening, or increased blood viscosity caused by other factors.  The hemorheologic-hemodynamic theory provides a more plausible explanation for the protective effect of HDL than “reverse transport of cholesterol.”

The hemorheologic-hemodynamic theory explains the existence of atherosclerotic plaques in synthetic arteriovenous grafts.10 These provide an extreme hemodynamic environment, where extremely high velocity blood flows through a curved vessel. These vessels are prone to thrombosis and development of atherosclerotic plaques despite anticoagulation. These vessels lack a tunica media, which received wisdom maintains is the origin of smooth muscle cells in atherosclerotic plaques via migration. The identification of the fibrocyte provides an alternative explanation for the origin of smooth muscle cells in atherosclerotic plaques.15, 16, 17 Being largely inanimate, the capacity of these vessels to respond to an injury with an inflammatory response, would be very limited to put it mildly. Further, this theory explains the benefit of blood donation.22 and drinking large quantities of water.23 Both of these very low risk interventions reduce blood viscosity.

The hemorheologic-hemodynamic eliminates reliance on the fatty streak in atherogenesis. Fatty streaks routinely resolve without sequelae.6 This is acknowledged by mainstream atherogenesis theory, which is unable to predict why a particular fatty streak progresses into an atherosclerotic plaque while the majority regress.4  Increased HDL particle size and increased low-shear blood viscosity caused by torcetrapib therapy could account for the increased cardiovascular mortality seen in clinical trials.