Blood characteristics effect on pulse wave velocity.

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Hemodynamics

Background:

• Pulse wave velocity (PWV) is a key indicator of vascular stiffness, often assessed using the Bramwell-Hill equation.
• The influence of blood density on PWV has been historically overlooked due to assumptions of negligible variation.
• Changes in blood density may represent a significant mechanical factor affecting wave propagation in the vasculature.

Purpose of the Study:

• To investigate the impact of mechanical and hemorheologic factors on PWV in patients with cardiovascular disease.
• To determine if blood density, quantified by a derived density score, is an independent predictor of PWV.
• To assess the independent contribution of various hemorheologic parameters to PWV.

Main Methods:

• Analysis of 814 patients with coronary arterial disease undergoing coronary angiography.
• Measurement of PWV, hemorheologic parameters (including high shear whole blood viscosity (WBV) and erythrocyte sedimentation rate (ESR)), and clinical parameters.
• Development of a 'density score' (sum of hemoglobin and total protein) as a proxy for whole blood density.
• Multiple linear regression analysis to identify independent predictors of PWV.

Main Results:

• Age, systolic blood pressure (SBP), high shear WBV, ESR, and density score showed initial correlations with PWV.
• Multivariable regression analysis revealed that only age, SBP, and density score remained significant independent predictors of PWV (p < 0.001).
• Hemorheologic parameters like RBC deformability, aggregation, and WBV did not independently influence PWV.

Conclusions:

• Blood density, represented by the density score, is a significant independent factor influencing PWV alongside age and SBP.
• Traditional hemorheologic parameters do not independently predict PWV in this patient cohort.
• The findings suggest incorporating blood density as a mechanical factor in understanding vascular stiffness and PWV.