Tubular stent

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS.
1A and 1C show a tubular segment of a stent according to the invention which consists of single closed loops 1 in the unexpanded and expanded state, respectively.
Each loop 1 is connected at a interconnection 4 with an adjacent loop 1.
FIG.
1B shows the stent 5 which consists of a longitudinal sequence with respect to the longitudinal axis 8 of the stent 5.
Possible variations of this stent structure are described below.
The stent 5 consists of single loops 1 or sequences of loops 1 which have an oval or circular cross section (see FIGS.
1A and 5A) and which are arranged in circumferential or longitudinal direction, 3 and 2 respectively, having at least one interconnection 4.
The single loops 1 may be formed with round wire by connecting its ends through, for example, welding, soldering and gluing, or they may be cut from tubes or flat material.
The originally formed loop element 1 can correspond to a compressed, i.
e.
unexpanded, form (small diameter of the stent) or to a completely expanded form (large diameter of the stent).
Depending on the material and its strength it may be more suitable for the manufacturing process and the physical characteristics of the stent to fold a basic form (which corresponds to the expanded or partly expanded diameter of the stent) on a balloon of a balloon catheter or to compress it or to fold a basic form (which corresponds to the compressed diameter) on the balloon.
In the latter case, the stent or its loop is deformed far beyond its basic form.
In the first case, it is only partly deformed beyond its basic form or not deformed at all.
The diameter of the basic stent form or its loop form is substantial for the deforming characteristics and the collapse resistance of the expanded stent.
The number of loops 1 of a sequence in the circumferential direction 3 (which is the expanding direction) depends on the necessary diameter of the expanded stent (for the maximum expansion of the stent for a predetermined vessel diameter)