Contact and friction between catheter and blood vessel

Therapeutic vascular catheterization techniques are sometimes hampered by the frictional forces between the blood vessel and the catheter, when contact points of the vessel are changing and deforming during the movement of the catheter. The goal of the present study was to characterize frictional interactions between the blood vessel wall and the catheter using experimental and numerical analysis. First, the frictional force was measured with an experimental apparatus that uses a ball and flattened porcine aorta to simulate frictional forces between the catheter and the vessel. Second, catheter motion was characterized by two-dimensional numerical calculations based on the experimental results. Experimental analysis demonstrated that slip occurred and that friction coefficient between the vessel and the catheter and the deformation of the specimen were small when the contact between the ball and the aorta occurred at a small angle. The compliance of the specimen in the normal direction obtained by the experiment was by far larger than that calculated according to the Hertzian contact theory. Numerical analysis shows that this difference of the parameter of the vessel, which must be determined accurately in surgical simulator, could affect the trajectory of the catheter.