Crush recoverable polymer scaffolds having a low crossing profile
A medical device includes a polymer scaffold crimped to a catheter having an expansion balloon. The scaffold, after being deployed by the balloon, provides a crush recovery of about 90% after the diameter of the scaffold has been pinched or crushed by 50%. The scaffold also has a reduced crimped profile and a modification of the scaffold's ring structure at the crowns that contributes to the reduced crimped profile.
1. A medical device implantable within a peripheral vessel of the body, comprising:
a scaffold formed from a polymer tube
configured for being crimped to a balloon,
the scaffold having a wall thickness of between 0.008″ and 0.0014″,
the scaffold having a pre-crimp diameter of between 7 mm and 10 mm,
the scaffold having a pattern of interconnected elements and
the scaffold having an expanded diameter when plastically deformed from a crimped state by inflation of the balloon,
wherein the scaffold attains at least 90% of its expanded diameter after being crushed to at least 75% of its expanded diameter for a crush duration of 0 to 5 minutes.
2. The medical device of claim 1 , wherein the scaffold attains greater than 80% of its expanded diameter after being crushed to 50% of its expanded diameter for a crush duration of 0 to 5 minutes.
3. The medical device of claim 2 , wherein
the scaffold is crushed using a pair of opposed flat metal plates,
the duration of crush is approximately 0 seconds, 1 minute or 5 minutes, and
the scaffold has a temperature of 20 degrees Celsius during the crush.
4. The medical device of claim 3 , wherein the scaffold is formed from a PLLA tube.
5. The medical device of claim 2 , wherein the interconnected elements include a plurality of rings and a plurality of links connecting each ring to at least one other ring,
wherein the interconnected elements form a plurality of closed cells, wherein a closed cell is connected to adjacent closed cells by a portion of the plurality of links,
wherein each ring includes a plurality of crowns each having a maximum crown angle of between 90 degrees and 115 degrees when the scaffold has the expanded diameter, and
wherein the closed cell is symmetric about two orthogonal axes with respect to the portion of the plurality links connecting the closed cell to the adjacent closed cells.
6. The medical device of claim 1 , wherein the interconnected elements include rings having crowns, and wherein a crown has an inner radius of about 0 inches.
7. The medical device of claim 1 , wherein the scaffold is cut from a tube having the pre-crimp diameter between (1.7)*(SD I )*(1.2) −1 and (1.0*(8130*(1.2) −1 , where SD I is the expanded diameter.
8. The medical device of claim 7 , wherein the expanded diameter (SD I ) is between 6 mm and 12 mm.
9. A medical device for being implanted within a peripheral vessel of the body, comprising:
a scaffold formed from a polymer tube
crimped to a balloon,
the scaffold having interconnected elements and
the scaffold having an expanded diameter when plastically deformed from a crimped state by inflation of the balloon;
wherein the scaffold attains greater than 80% of its expanded diameter after being crushed to 50% of its expanded diameter for a crush duration of between 0 and 5 minutes; and
wherein the crimped scaffold has a crimped diameter of about equal to or less than a theoretical minimum diameter for the crimped scaffold; and
wherein the interconnected elements include a plurality of crowns, each having a maximum crown angle of between 90 degrees and 115 degrees when the scaffold has the expanded diameter.
10. A medical device, comprising:
a polymer scaffold crimped to a balloon and when plastically deformed by the balloon the scaffold attains an expanded diameter;
wherein the crimped scaffold has a pattern of interconnected elements, the interconnected elements including
a plurality of rings and a plurality of links connecting each ring to at least one other ring, and
a plurality of closed cells, wherein a closed cell is connected to adjacent closed cells by a portion of the plurality of links,
wherein the closed cell is symmetric about two orthogonal axes with respect to the portion of the plurality links connecting the closed cell to the adjacent closed cells; and
wherein the scaffold is capable of regaining more than 80% of its expanded diameter after being crushed to 50% of its expanded diameter for a crush duration of between 0 and 5 minutes.
11. The medical device of claim 10 , wherein the scaffold is made from a tube comprising PLLA and wherein the tube is radially expanded such that the scaffold formed from the tube has a morphology comprising circumferentially orientated polymer chains.
12. The medical device of claim 10 , wherein the scaffold expanded diameter is equal to, or greater than 6 mm, and the scaffold has a wall thickness of greater than 0.008 inches.
13. A medical device implantable within a peripheral vessel of the body, comprising:
a scaffold formed from a polymer tube
crimped to a balloon,
the scaffold having interconnected elements, and
the scaffold having a diameter when plastically deformed from a crimped state by inflation of the balloon to at least a nominal diameter of the balloon;
wherein the plastically deformed scaffold attains greater than 80% of the plastically deformed diameter after being crushed to at least 75% of the plastically deformed diameter for a crush duration of between 0 and 5 minutes; and
wherein the interconnected elements include a plurality of crowns, each having a maximum crown angle of between 90 degrees and 115 degrees when the scaffold has the plastically deformed diameter.
14. The medical device of claim 13 , wherein the scaffold attains greater than 80% of the plastically deformed diameter after being crushed to 50% of the plastically deformed diameter for a crush duration of between 0 and 5 minutes.
15. The medical device of claim 13 , wherein the scaffold attains greater than 90% of the plastically deformed diameter after being crushed to at least 75% of the plastically deformed diameter for a crush duration of between 0 and 5 minutes.
16. The medical device of claim 13 , wherein the scaffold is cut from a tube having a tube diameter that is between 0.92 and 1.4 times the inflated diameter.
17. The medical device of claim 13 , wherein
the scaffold is crushed using a pair of opposed flat metal plates,
the duration of crush is approximately 0 seconds, 1 minute or 5 minutes, and
the scaffold has a temperature of 20 degrees Celsius during the crush.