Abstract: A medical apparatus for removing deposits from arterial and venous walls comprising a partially hollow body, essentially circular in cross-section, having an insertion end and a withdrawal end. At least two shell-shaped parts extend from the insertion end towards the withdrawal end pivotally connected to the body proximate the insertion end and forming a cutting edge distal from the insertion end. The shell-shaped parts have a convex surface towards the cutting edge facing away from the body such that the cutting edge generally faces toward the central axis of the body of the apparatus. At least two leaf arms pivotally connected at one end to each other, the other end of each leaf arm being pivotally connected to one of the shell-shaped parts, are disposed inside the partially hollow body and are connected to means for expanding the shell-shaped parts. Means for withdrawing the body from a vessel are connected to the withdrawal end of the body.

Abstract: A medical instrument for insertion into human vessels for removing plaque deposits from the walls of arteries and/or veins. It is formulated of a partially hollow and, seen in cross section, circular body, which by the means of a controllable, withdraw cutting device, can be extracted from the vessel after performing its primary function of slicing away any plaque deposits from the artery or vein wall, and collecting them in a residue chamber for removal. The tangent of the angles of the cutting section is defined by the central axis of the hollow body and a tangential line intersecting the cutting section increases continuously as the point of intersection of the tangential line with the cutting section is moved in the direction of the cutting edges. The angle of the cutting edges are more than 10 degrees, but less than 90 degrees, from the axis of the hollow body.