Scaffolds having radiopaque markers

• US 9,999,527 B2
• Filed: 02/11/2015
• Issued: 06/19/2018
• Est. Priority Date: 02/11/2015
• Status: Expired due to Fees

• Current Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories)
• Original Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories)
• Inventors: Pacetti, Stephen, Bei, Joan, Wang, Karen, Liu, Annie
• Primary Examiner(s): Afzali, Sarang
• Assistant Examiner(s): FORD, DARRELL CHRISTOPHER
• Application Number:
  US14/620,096
• Publication Number:
  US 20160228267A1
• Time in Patent Office: 1,224 Days
• Field of Search: 29428, 2952506, 264263, 264279
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/91533 characterised by the phase between adjacent bands
• CPC Class Codes: A61F 2002/91575 connected peak to trough
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2210/0071 thermoplastic
• CPC Class Codes: A61F 2240/001 Designing or manufacturing processes
• CPC Class Codes: A61F 2250/0098 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61L 31/04 Macromolecular materials
• CPC Class Codes: A61L 31/18 Materials at least partially X-ray or laser opaque

Abstract

A scaffold includes a radiopaque marker connected to a strut. The marker is retained within the strut by one or more of a mechanical interference fit, a polymer coating or melt, and/or by friction. The marker can take the form of a bead, rivet or snap-in marker, or a tube deformed when attached to the strut. The strut is made from a tube. The strut has a thickness of about 100 microns.

Claims

1. A method for making a medical device, the method comprising:

providing a scaffold comprising a first polymer, the scaffold including a strut having a hole formed in the strut, wherein the hole has a hole volume and a hole opening located on a first side of the strut; and

attaching a marker to the scaffold, the marker comprising a radiopaque material and having a first end, a second end, and a medial portion between the first end and the second end, wherein the marker has a volume less than the hole volume, the attaching comprising the steps of;

press-fitting the marker into the hole, whereupon the medial portion engages the hole, the first end faces the hole opening, and the entire first end is recessed from the hole opening, thereby producing a space between the first end and the hole opening, and

filling at least a portion of the space with a second polymer,

thereby making the medical device.

2. The method of claim 1, wherein the second polymer is in a molten state or the second polymer is dissolved in a solvent when filling the at least the portion of the space with the second polymer.

3. The method of claim 2, wherein the at least a portion of the space is filled with a drug-polymer coating comprising the second polymer.

4. The method of claim 1, wherein the scaffold comprises a plurality of struts, the method further comprising the step of coating the plurality of struts with a third polymer after the filling step.

5. The method of claim 4, wherein the coating is a drug-polymer coating comprising the third polymer.

6. The method of claim 4, wherein a thickness TC measured from an abluminal surface to a luminal surface of the third polymer coating adjacent the marker is related to a distance L′

measured from an abluminal surface to a luminal surface of the third polymer coating at the marker as 1.1≤

L′

/TC≤

1.5.

7. The method of claim 4, wherein the first polymer comprises poly(L-lactide), the scaffold has a wall thickness between 80 and 120 microns, and a distance L′

measured from an abluminal surface to a luminal surface of the third polymer coating at the marker is between 100 microns and 150 microns.

8. The method of claim 1, wherein a bump comprising the second polymer covers the hole opening after the filling step.

9. The method of claim 8, wherein a wall thickness TS of a strut portion adjacent the marker is related to a distance L′

measured from an abluminal surface to a luminal surface at the marker as 1.1≤

L′

/TS≤

1.5, where L′

includes a distance of the bump that extends beyond the hole opening and TS.

10. The method of claim 1, wherein the strut has a first side and a second side and the hole has a first hole opening and a second hole opening located, respectively, on the first side and the second side, and the second end of the marker faces the second hole opening and the first end of the marker faces the first hole opening, and

wherein the filling step further includes depositing the second polymer in the second hole opening.

11. The method of claim 10, wherein the entire second end of the marker is recessed from the second hole opening, and the filling step further includes filling at least a portion of a space between the second end and the second hole opening.

12. The method of claim 1, wherein the marker is comprised of platinum, platinum/iridium alloy, iridium, tantalum, palladium, tungsten, niobium, zirconium, iron, zinc, magnesium, manganese, or alloys thereof.

13. The method of claim 1, wherein the hole is polygonal-shaped or has a roughened wall, and wherein at least one gap is present between the medial portion of the marker and the hole such that the filling step deposits the second polymer in the at least one gap.