Some possible effects of a catheter on the arterial wall.

When a catheter is inserted through an artery, the wall shear stress increases and the secondary flow exhibits an increased number of instantaneous vortices. These effects become more evident when the annular gap between the catheter and the artery becomes more narrow. Accordingly it is suggested that these factors may affect the preferential distribution of the atheromatous plaques at the sites of the wall with an increased permeability.