Abstract: A clinically usable pump apparatus for a dilatation device comprising a dilatation catheter, preferably for opening a stenosis and occlusions or for closing vessels, ducts and openings, while using a pumpable medium, which comprises a pump structured to accomplish the double function of producing positive pressure and negative pressure and operatively connected with the dilatation catheter.

Abstract: A catheter arrangement for opening or closing hollow spaces, cavities, passages and the like comprising a guide catheter and a dilatation catheter. A dilatation element arranged at the dilatation catheter has an at least partially cylindrical foldable wall. The catheterization technique employable with such catheter arrangement contemplates introducing the guide catheter by forces applied in translatory and rotational direction and engaging at the surface layer of the guide catheter, into the near region of the hollow space to be opened or closed, then inserting the dilatation catheter through a bore of the guide catheter, with the dilatation element having in its internal space a negative pressure in relation to the hollow space which is to be opened or closed.