Viscosity and ischemic heart disease

Epidemiologic and experimental data support the involvement of plasma and blood viscosity in the various clinical stages of ischemic heart disease. The hemorheologic abnormalities present in survivors of myocardial infarction correlate with the onset of acute phase protein changes. The causal relationship between blood viscosity and ischemic heart disease cannot be clearly stated from these case-control series; however, studies in which cohorts with unstable angina pectoris are monitored prospectively support the role of blood viscosity in identifying patients at high risk of progressing to acute myocardial infarction. Further evidence derives from a prospective population study that demonstrates the impact of plasma viscosity as a predictor for future ischemic heart disease events. Components of blood and plasma viscosity shown to elevate viscosity include fibrinogen and conventional biochemical markers of ischemic heart disease such as cholesterol and other lipoproteins. Future studies are needed to establish the practical utility of measuring viscosity in establishing ischemic heart disease risk, and the determination of whether strategies to reduce viscosity either acutely through hemodilution or chronically by lowering concentrations of lipoproteins will reduce cardiovascular risk and event rate remains a future challenge.