Implantable vascular and endoluminal stents and process of fabricating the same

• US 5,843,117 A
• Filed: 02/14/1996
• Issued: 12/01/1998
• Est. Priority Date: 02/14/1996
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: InFlow Dynamics, Inc. (Boston Scientific Corporation)
• Inventors: Fliedner, Thilo, Alt, Eckhard, Stemberger, Axel, Alter, Robert
• Primary Examiner(s): Thaler, Michael H.
• Application Number:
  US08/599,880
• Time in Patent Office: 1,021 Days
• Field of Search: 606/108, 606/198, 606/191, 606/195, 623/1, 623/12, 623/901
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/86 Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2002/91541 Adjacent bands are arranged out of phase
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2240/001 Designing or manufacturing processes
• CPC Class Codes: A61F 2250/0036 differing in thickness
• CPC Class Codes: A61F 2250/0098 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: C21D 1/773 under reduced pressure or vacuum
• CPC Class Codes: Y10S 623/901 Method of manufacturing prosthetic device

Abstract

A vascular or endoluminal stent adapted for deployment in a vessel or tract of a patient to maintain an open lumen therein is formed from a metal open-ended tube which is the single component of the stent. The tube has a multiplicity of holes cut by laser through its wall. The through-holes are encompassed by serpentines that constitute the wall, the serpentines extending sinusoidally each in multiple 360° wavelengths in a single turn about the axis of the tube and juxtaposed in plural substantially identical segments disposed with regularity along the axis. Each segment has a length equal to the distance between crests and troughs of the sinusoid. Adjacent serpentines are joined together at crest and trough, respectively, so that their interconnections are 180° out of phase relative to their wavelength. The serpentines and interconnections thereof are shaped throughout for optimum uniform expansion of the stent during deployment thereof, including a notch substantially symmetrically located at either side of the junction of the respective crest and trough of the interconnections between adjacent serpentines. The serpentines are substantially devoid of sharp corners and edges, except at the notches, and each serpentine has an oval cross-section. The regularity of the segments is interrupted at least once along the axis of the tube by serpentines oriented differently from the others, used to maintain the tube'"'"'s length substantially invariant despite radial expansion of the stent during deployment. The serpentines are pre-stressed and annealed before deployment of the stent to ease deployment and enhance symmetrical radial expansion. The exterior surface of the tube is longitudinally tapered from its mid-point toward its ends, and substantially rounded surfaces prevail throughout the tube.

Claims

1. A vascular or endoluminal stent adapted to be expanded from a small diameter production state to a larger diameter deployed state for deployment in a vessel or tract of a patient to maintain an open lumen therein, said stent comprising a biocompatible hollow tube with a multiplicity of openings through an open-ended tubular wall thereof, said openings having a closed oval shape when said stent is in the production state, according to the shape of a plurality of serpentine elements bounding said openings within at least a substantial portion of said wall and running circumferentially in juxtaposed sine wave patterns, each of uniform multiple cycles, wherein adjacent ones of said patterns are offset 180 degrees out of phase from each other about the circumference of the tubular wall, are directly connected together without intervening bridges at the most closely confronting points of each pair of out of phase cycles of adjacent ones of the sine wave patterns, and are uniformly displaced longitudinally along an axis of the tube, said tube constituting a single member from which the entire stent is fabricated,

wherein the uniform longitudinal displacement of the circumferential substantially sine wave-like patterns is interrupted at least once along the axis of the stent by transversely oriented serpentine elements that run longitudinally within said wall in juxtaposed at least partial substantially sine wave-like patterns having openings through the wall which are shaped according to the transversely oriented serpentine elements, adjacent ones of the transverse patterns being offset from each other by a 180°

cyclical phase difference at interconnecting points therebetween along the circumference of the tube, said transversely oriented serpentine elements being adapted to maintain the length of said tube substantially invariant with radial expansion of the stent.

2. A process for fabricating a vascular or endoluminal stent adapted for deployment in a vessel or tract of a patient to maintain an open lumen therein, comprising the step of laser cutting a biocompatible hollow tube to form a multiplicity of openings through an open-ended tubular wall thereof while simultaneously forming a plurality of serpentine elements in the wall running circumferentially therein in juxtaposed substantially sine wave patterns of uniform multiple wavelengths, with adjacent ones of said patterns tangentially contacting each other and interconnected directly at each point of tangential contact between waves thereof offset from each other by 180 degrees about the circumference of the tubular wall, said adjacent patterns arranged in uniform longitudinally displaced segments along the axis of the tube, whereby each of said openings in the wall deviates from a substantially oval shape only by virtue of notches formed at each side of the interconnection between waves at the respective points of tangential contact,

including the step of interrupting the longitudinal segments in which the substantially sine wave patterns are lying, at least once along the axis of the tube by laser cutting transversely oriented serpentine elements in the wall that run longitudinally in at least partial substantially sine wave patterns and juxtaposed circumferentially, while simultaneously cutting openings of said transversely oriented serpentine elements through the wall, and with adjacent ones of the transversely oriented patterns being offset from each other by 180°

relative to their wavelengths at interconnecting points therebetween along the circumference of the tube, so that said transversely oriented serpentine elements will act to maintain the length of said tube substantially invariant with radial expansion of the stent.

3. A vascular or endoluminal stent adapted for deployment in a vessel or tract of a patient to maintain an open lumen therein, the stent comprising a metal open-ended tube having a multiplicity of through holes in the wall thereof, said tube being the single component of the stent with elements thereof being shaped throughout for optimizing symmetrical expansion of the stent without substantial deformation from a tubular shape during deployment thereof, the inner lumen of the tube being of uniform diameter throughout and the outer diameter of the tube ranging substantially uniformly from a maximum at the mid-point of the length of the tube to a minimum at each end of the tube whereby the tube wall is longitudinally tapered at the exterior surface thereof to be more flexible at its ends than at its mid-point.

4. A process for fabricating a vascular or endoluminal stent adapted for deployment in a vessel or tract of a patient to maintain an open lumen therein, comprising the steps of forming a multiplicity of generally oval-shaped openings through an open-ended tubular wall of a biocompatible hollow tube, to leave a multiplicity of interconnected serpentine elements bounding the openings and maintaining the tubular shape of the wall, tapering the outer surface of the wall to be thicker from the middle of the length to each thinner end thereof while maintaining a uniform diameter throughout the lumen of the tube, so as to render the stent more rigid in the middle and more flexible at the ends thereof.