Method for loading a medical device into a delivery system

• US 8,191,220 B2
• Filed: 12/04/2007
• Issued: 06/05/2012
• Est. Priority Date: 12/04/2006
• Status: Active Grant

• Current Assignee: Cook Medical Incorporated (Cook Group Incorporated)
• Original Assignee: Cook Medical Incorporated (Cook Group Incorporated)
• Inventors: Magnuson, Mark A., Parker, Fred T., Hansen, Palle M.
• Primary Examiner(s): COZART, JERMIE E
• Application Number:
  US11/950,244
• Publication Number:
  US 20080215131A1
• Time in Patent Office: 1,645 Days
• Field of Search: 294/05, 294/47, 148/563, 148/402, 623/1.18, 623/1.19
• US Class Current: 29/405
• CPC Class Codes: A61F 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2/9522 Means for mounting a stent or stent-graft onto or into a placement instrument
• CPC Class Codes: A61F 2210/0014 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2250/0042 differing in shape-memory transition temperatures, e.g. in martensitic transition temperature, in austenitic transition temperature
• CPC Class Codes: C22F 1/00 Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working apparatus for mechanical working of metal B21, B23, B24
• CPC Class Codes: C22F 1/006 Resulting in heat recoverable alloys with a memory effect
• CPC Class Codes: C22F 1/10 of nickel or cobalt or alloys based thereon
• CPC Class Codes: Y10T 29/4976 Temperature
• CPC Class Codes: Y10T 29/49865 by temperature differential [e.g., shrink fit]

Abstract

A process to load a medical device comprising a shape memory material into a delivery system is described herein. According to one aspect, the method includes applying a force to the medical device to obtain a delivery configuration thereof, where the device is at a first temperature within an R-phase temperature range of the shape memory material during application of the force. The medical device is cooled in the delivery configuration to a second temperature at or below a martensite finish temperature of the shape memory material. The force is then removed from the medical device, and the device is loaded into a delivery system. Preferably, the medical device substantially maintains the delivery configuration during the loading process.

Claims

1. A process for loading a medical device into a delivery system prior to insertion into a body lumen, the process comprising:

applying a force to a medical device comprising a shape memory material to obtain a delivery configuration of the medical device, the medical device being at a first temperature within an R-phase temperature range of the shape memory material during the applying;

removing the force from the medical device; and

after removing the force, loading the medical device into a delivery system.

2. The process according to claim 1, further comprising cooling the medical device in the delivery configuration to a second temperature below the first temperature prior to removing the force from the medical device.

3. The process according to claim 2, wherein the second temperature is at or below a martensite finish temperature of the shape memory material.

4. The process according to claim 2, wherein the medical device recovers at least a portion of the delivery configuration upon recooling to the second temperature following removal of the force.

5. The process according to claim 1, wherein the medical device substantially maintains the delivery configuration for a time of at least about 5 seconds following removal of the force.

6. The process according to claim 1, wherein the loading is carried out in an environment maintained at a temperature of less than an austenite start temperature of the shape memory material.

7. The process according to claim 1, further comprising warming the medical device from an initial temperature to the first temperature in the R-phase temperature range.

8. The process according to claim 7, wherein the R-phase temperature range extends from an R′

-phase start temperature to below an austenite start temperature of the shape memory material.

9. The process according to claim 8, wherein the initial temperature is at or below a martensite finish temperature of the shape memory material.

10. The process according to claim 1, further comprising cooling the medical device from a starting temperature to the first temperature in the R-phase temperature range.

11. The process according to claim 10, wherein the R-phase temperature range extends from an R-phase start temperature to above a martensite start temperature of the shape memory alloy.

12. The process according to claim 11, wherein the starting temperature is at or above an austenite finish temperature of the shape memory material.

13. The process according to claim 1, wherein the medical device is a self-expanding stent,

wherein the force is a compressive radial force,

wherein the delivery configuration is a compressed configuration, and

wherein the delivery system is a tube, and

further comprising warming the stent from an initial temperature at or below a martensite finish temperature to the first temperature within the R-phase temperature range, and

further comprising cooling the stent in the compressed configuration to a second temperature at or below a martensite finish temperature of the shape memory alloy prior to removing the compressive radial force from the stent.

14. The process according to claim 1, further comprising, after loading the medical device into the delivery system, inserting the medical device into a body lumen.

15. A process for loading a medical device into a delivery system, the process comprising:

applying a force to a medical device comprising a shape memory material to obtain a delivery configuration of the medical device, the medical device being at a first temperature within an R-phase temperature range of the shape memory material during the applying;

cooling the medical device in the delivery configuration to a second temperature at or below a martensite finish temperature of the shape memory material;

removing the force from the medical device following the cooling;

loading the medical device into a delivery system, wherein the medical device substantially maintains the delivery configuration during loading.

16. The process according to claim 15, further comprising warming the medical device from an initial temperature to the first temperature in the R-phase temperature range.

17. The process according to claim 16, wherein the R-phase temperature range extends from an R′

-phase start temperature to below an austenite start temperature of the shape memory material.

18. The process according to claim 15, further comprising cooling the medical device from a starting temperature to the first temperature in the R-phase temperature range.

19. The process according to claim 18, wherein the R-phase temperature range extends from an R-phase start temperature to above a martensite start temperature of the shape memory alloy.

20. A process for a loading a stent into a delivery system, the process comprising:

cooling a stent comprising a shape memory material from a temperature at or above an austenite finish temperature of the shape memory material to an initial temperature at or below a martensite finish temperature of the shape memory material;

warming the stent from the initial temperature to a first temperature at or above an R′

-phase start temperature and below an austenite start temperature of the shape memory material;

applying a force to the stent to obtain a compressed configuration of the stent, the stent being at the first temperature during the applying;

cooling the stent in the compressed configuration to a second temperature at or below the martensite finish temperature;

removing the force from the stent after the cooling in the compressed configuration; and

loading the stent into a delivery system after removing the force, wherein the stent substantially maintains the compressed configuration during loading.

21. The process according to claim 20, wherein loading the stent into the delivery system comprises a force of less than about 1 N.