Hydro- and hemodynamic effects of catheterization of vessels. V. Experimental and clinical catheterization of stenoses.

The volumetric flow rate and the pressure course through free and catheterized stenoses have been analysed experimentally. The influence of the following parameters has been considered: (a) the penetration depth of the catheter into stenoses of various geometrical shapes and various dimensions, (b) the length of the stenosis, (c) the size of the annular lumen area between the catheter and the stenosis wall, (d) the geometrical shape of the stenosis. Some previous attempts to derive a simple relation between the volumetric flow through and the pressure fall across stenosis with and without introduced catheter are discussed. Clinical pressure measurements across renal artery stenoses are given, and the validity of catheter-measured pressure gradients across stenoses is discussed.