Estimation of aortic-to-radial artery distribution of arterial wall elasticity

The purpose of this paper is to clarify the cause of the peaking/steepening phenomenon and pressure gradient after cardiopulmonary bypass by measuring the distribution of intra-arterial pressures and that of pulse wave velocities and estimating the vascular wall elasticity's from the aorta to radial artery.

We measured the intra-arterial pressures and pulse wave velocities simultaneously from aorta to radial artery using a guide-wire tipped with a pressure transducer before and after cardio-pulmonary bypass (CPB), and calculated the distribution of the stiffness parameters (called β) of aorta-to-radial artery wall. Thereafter, we converted β's into the wall elasticity's.

We found that before CPB the intra-vascular pressures increased gradually from aorta to radial artery, and that corresponding β and wall elasticity increased simultaneously. After CPB, the intra-arterial pressure and β or wall elasticity showed the gradual decrease from aorta to radial artery. These results suggest that aortic-to-radial artery pressure change is attributed to gradual change in β, that is, in the wall elasticity.

The findings indicate that the gradual rise and fall in β, namely, the increase and decrease in vascular elasticity may account for the peaking, steepening and pressure gradient.