US20080072653A1

US20080072653A1 - Cold collapse method and apparatus

Info

Publication number: US20080072653A1
Application number: US11/524,133
Authority: US
Inventors: Matthew J. Gillick; John E. Papp
Original assignee: Advanced Cardiovascular Systems Inc
Current assignee: Abbott Cardiovascular Systems Inc
Priority date: 2006-09-20
Filing date: 2006-09-20
Publication date: 2008-03-27

Abstract

A system and method are disclosed for collapsing medical devices, such as self-expanding, drug-eluting stents for loading into delivery catheters. The collapsing apparatus may be used for crimping expandable stents and other devices onto a balloon catheter. The medical device is cooled below the austenitic phase transformation temperature of the material forming the device, such as stainless steel or nitinol, and may be cooled until the material has fully transformed to the martenstitic state. For coated medical devices, the device is warmed to a temperature just below the beginning of austenite phase transformation prior to collapsing. An apparatus having a plurality of offset blades, linear bearings, radial bearings and an actuator mechanism is provided for collapsing the medical device. The system is configured with a mandrel subassembly to push the medical device into a catheter sheath, and with a nozzle subassembly to direct cold gas to the medical device.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus and method for collapsing a device, and more specifically for collapsing an intraluminal medical device, such as a stent or an embolic filter. The device may be collapsed and placed into a sheath or crimped onto the distal end of a delivery catheter or balloon catheter, such as those used, for example, in percutaneous transluminal coronary angioplasty (PTCA) procedures or in percutaneous transluminal angioplasty (PTA) procedures. The present invention may be adapted for collapsing or crimping balloon expandable stents and self-expanding stents, such as those made from nickel-titanium alloys (nitinol).
As used herein, the term “proximal” is used as the end or portion that is closest to the user (for example, from the outside of the containment housing), and the the term “distal” is used as the end or portion that is furthest from the user (for example, towards the inside of the containment housing). As used herein, the term “crimping” is used to refer to the process of reducing the size of a device, such as a stent, about a mandrel, a wire, a delivery catheter, a balloon catheter or other longitudinally disposed piece. As used herein, the term “collapsing” is used to refer to the process of reducing the size of a device, such as a stent or other medical device, without necessarily having a longitudinally disposed member within the device being collapsed.
In angioplasty procedures, restenosis of the artery may develop at or near the treatment area, which may require another angioplasty procedure, a surgical bypass operation, or some other method of repairing or strengthening the area. To reduce the likelihood of the development of restenosis and to strengthen the area, a physician can implant an intravascular prosthesis for maintaining vascular patency, commonly known as a stent, inside the artery at the treated area. The stent is transported in its low profile delivery diameter through the patient's vasculature. At the deployment site, the stent is expanded to a larger diameter, often by inflating the balloon portion of the catheter. The stent also may be formed from a material so as to allow it to self-expand when released from a sheath.
Since the catheter and stent travel through the patient's vasculature, and typically through the coronary arteries, the stent must have a small delivery diameter and must be firmly attached to the catheter until the physician is ready to implant it. Thus, the stent must be loaded onto the catheter or within a sheath so that it does not interfere with delivery, and it must not come off the catheter or expand until it is at the desired location within the vasculature.
In procedures where the stent is placed over the balloon portion of the catheter, it is necessary to crimp the stent onto the balloon portion to reduce its diameter and to prevent it from sliding off the catheter when the catheter is advanced through the patient's vasculature. Where the stent is not reliably crimped onto the catheter, the stent may slide off the catheter and into the patient's vasculature prematurely as a loose foreign body, possibly causing blood clots in the vasculature, including thrombosis. Therefore, it is important to ensure the proper crimping of a stent onto a catheter in a uniform and reliable manner. This crimping is sometimes done by hand, which can be unsatisfactory due to the uneven application of force resulting in non-uniform crimps. In addition, it is difficult to visually judge when a uniform and reliable crimp has been applied.
Some self-expanding stents, such as those made from nitinol, are difficult to load by hand into a delivery device such as a catheter or onto a balloon and then covered by a sheath. Self-expanding stents may be compressed or crimped to a small diameter and then inserted into a delivery catheter where the stent remains until it is pushed out and expands into the vessel. Further, the more the stent is handled the higher the likelihood of human error. Accordingly, there is a need in the art for a device for reliably crimping or compressing a self-expanding stent and inserting it into a catheter or sheath.
The present invention solves these and other problems associated with known crimping and collapsing apparatus and methods.

SUMMARY OF THE INVENTION

The cold collapser system and method of the present invention are specifically directed to collapsing and/or crimping a self-expanding, drug-eluting stent (SE-DES) to a small diameter for the purpose of loading into a delivery catheter. The collapser system and method of the present invention may also be used to crimp or collapse mechanically expandable stents or other medical devices (with or without a drug coating) onto a balloon catheter. For purposes of simplicity, the text and drawings herein are generally directed to self-expanding nitinol stents; however, those of ordinary skill in the art will appreciate that the various apparatus and methods described herein may be adapted for use with other materials, such as stainless steel, and other devices, medical or otherwise. The present invention is particularly useful with stents, grafts, tubular prostheses, embolic devices, embolic filters, and embolic retrieval devices.
The act of collapsing an SE-DES and pushing it into a catheter sheath provides several challenges. Because the stent is self-expanding, it will produce a radial force outward on any device or sheath that constrains it. The stent must be pushed from the collapsing mechanism into the catheter sheath forcefully because of the friction produced by the outward radial force, thus creating unwanted stress on the drug coating. The friction and stress on this coating has the potential to cause surface scratches or detachment of the coating. The radial force may be eliminated by cooling the stent until the stent alloy has fully transformed to the martensitic state (M_t), but an unwanted side effect is that the drug coating becomes brittle at this low temperature and can crack when the stent is collapsed.
The present invention addresses these issues in several ways. First the temperature of the stent is lowered below the austenitic phase transformation temperature (A_s) and may be lowered until the martensitic phase transformation of the stent alloy is completed—this reduces or eliminates the radial force exerted by the stent on the collapsing machine. Next, the stent is warmed to a temperature just below the beginning of austenite phase transformation in order to bring the drug/polymer coating to a non-brittle temperature for collapsing. Finally, the diameter of the stent is reduced by the collapsing apparatus of the present invention, and a mandrel is used to push the collapsed stent into a sheath. The temperature change and control may achieved by the use of commercially available refrigeration units that generate cold gas (for example, air or nitrogen) at a controlled temperature. Each refrigeration unit is integrated with a containment housing and other apparatus of the present invention that direct the cold gas flow to the stent, collapses the stent, provides fixturing for the sheath and a pushing mandrel, and controls temperature set points. Furthermore, the refrigeration units may be augmented or replaced by other cold gas sources, such as liquid nitrogen tanks and temperature control units.
The cold collapser system of the present invention includes a first cold gas source, a second cold gas source, and a jaws subassembly in fluid communication with the first cold gas source and the second cold gas source. The collapsing system further includes a nozzle subassembly in fluid communication with the first cold gas source and the second cold gas source, the nozzle subassembly being positioned proximate the jaws subassembly. The collapsing system includes a mandrel subassembly having a mandrel slidably disposed within a portion of the jaws subassembly and a portion of the nozzle subassembly. Portions of the collapsing system are contained within a housing having a proximal wall, wherein the proximal wall is configured to slidably retain an arm connected to the mandrel. The proximal wall is also configured with an aperture for removably retaining a sheath holder configured to retain a sheath. A proximal portion of the mandrel passes into the sheath and sheath holder when the arm of the mandrel subassembly is moved in a proximal direction. The mandrel is configured with a middle portion having a diameter larger than a diameter of the proximal portion of the mandrel. The collapsing system may be further configured with a thermocouple subassembly having a thermocouple slidably disposed within a portion of the nozzle subassembly.
The cold collapser system of the present invention is configured with a first cold gas source (for example, a gas chiller) for providing a first gas having a temperature from minus 60° C. to minus 90° C., and is further configured with a second cold gas source (for example, a gas chiller) for providing gas having a temperature from minus 40° C. to 20° C. The first cold gas source may instead be configured with a cold gas supply, such as liquid nitrogen, for providing gas having a temperature from minus 90° C. to minus 150° C. Alternatively, the first cold gas source and the second cold gas source may be fed from a common cold gas supply, such as liquid nitrogen, so as to provide the first cold gas source with gas having a temperature, for example, from minus 60° C. to minus 150° C., and to provide the second cold gas source with gas having a temperature, for example, from minus 40° C. to 20° C., wherein the second cold gas source may be a mixture of liquid nitrogen and room temperature nitrogen gas controlled to a desired warming temperature.
The jaws subassembly of the cold collapser system of the present invention is configured to include at least two first blades, each having at least one aperture and at least one groove (semi-circular cutout). The jaws subassembly further includes at least two second blades, each having at least one aperture and at least one groove (semi-circular cutout). The jaws subassembly further includes a proximal driver and a distal driver linked together and configured to engage the first ends and the second ends of each first blade and each second blade. The jaws subassembly further includes a plurality of linear bearings disposed within the apertures of the first blades and the apertures of the second blades. The grooves of the first blades are positioned to accept the linear bearings of the second blades, and the grooves of the second blades are positioned to accept the linear bearings of the first blades. Each first blade is configured with a beveled edge having a first side and a second side joining at a first tip. Each second blade also is configured with a beveled edge having a first side and a second side joining at a second tip. The set of first blades and each second blade are positioned within the housing to move relative to each other from a first position, with the first and second tips offset from each other by a first distance, to a second position, with the first and second tips offset from each other by a second distance different than the first distance. Radial motion of a linking mechanism causes the first and second tips to move from the first position that forms a lumen within the housing having a first diameter to the second position that causes first and second tips to form a lumen having a second diameter. The blades may be formed from stainless steel, plated with nickel and polished to a substantially defect free surface.
The method of the present invention for collapsing a stent or medical device includes providing the collapsing apparatus of the present invention and inserting the stent or other medical device at a first (expanded) diameter onto the mandrel and moving the stent into the jaws subassembly in the containment housing. The first cold gas is directed to the nozzle subassembly so as to introduce the first gas into the jaws subassembly, and the temperature of the stent is lowered below the austenitic phase transformation temperature and may be lowered below the temperature that completes the martensitic phase transformation. The second cold gas (warmer than the first cold gas) is directed to the nozzle subassembly so as to introduce the second cold gas into the jaws subassembly such that the temperature of the stent is raised (for example, to reduce cracking of the drug coating), but remains below the austenitic phase transformation temperature. The blades of the jaws are then rotated around the stent to collapse the stent to a second, smaller diameter. The mandrel arm is then used to push the stent into the sheath in the sheath holder. The sheath may be part of a delivery catheter or may be used to transfer the stent into a delivery catheter. Alternatively, the method and application of the present invention may be used to collapse the stent or other medical device directly on a delivery catheter or a balloon catheter.
Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of the cold collapser system of the present invention.

FIG. 2 depicts a perspective view of one embodiment of the containment subsystem of the present invention.

FIG. 3A depicts a perspective view of a cover of the housing of the cold collapser system of the present invention.

FIG. 3B depicts a front plan view of a front panel of the housing of the cold collapser system of the present invention.

FIG. 3C depicts a front plan view of a side wall of the housing that provides connections to the cold air subsystem of the present invention.

FIG. 4 is a top plan view of a bottom plate of the containment subsystem of the cold collapser system of the present invention.

FIGS. 5A, 5B and 5C are a proximal perspective, a front plan view and a side plan view, respectively, of the plug for the aperture in the front panel for the arm of the mandrel subsystem.

FIGS. 6A-6D are a distal perspective, a distal end plan view, a side plan view and a side cross-sectional view, respectively, of the sheath holder (plug) of the present invention.

FIG. 7 is a perspective drawing (cover assembly removed) of the cold collapser system of the present invention including portions of the air chilling subsystem, the mandrel subsystem and the device collapser (crimping) subsystem.

FIG. 8 depicts a mandrel subassembly of the present invention.

FIG. 9 depicts a thermocouple subassembly of the present invention.

FIG. 10 depicts an embodiment of the cold air nozzle subassembly of the cold collapser system of the present invention.

FIGS. 11A-11F depict a distal perspective, a proximal plan view, a distal plan view, a side cross-sectional view, a side plan view and a proximal perspective, respectively, of the nozzle assembly shown in FIG. 10.

FIG. 12 depicts a partial perspective (containment cover removed) of the cold collapser system of the present invention showing the cooling subassembly, the mandrel subassembly and the jaws subassembly with the housing removed.

FIG. 13 depicts a partial perspective (containment cover removed) of the cold collapser system of the present invention including the collapsing (crimping) subsystem, wherein the housing and jaws subassembly are depicted in their pre-assembly configuration.

FIGS. 14A-14D depict a distal perspective view of the jaws subassembly, a distal perspective view of the jaws housing, a distal plan view of the jaws housing and a bottom plan view of the jaws housing, respectively, of the present invention.

FIG. 15 depicts a distal perspective view of the jaws assembly, linear bearings and cam assemblies of the cold collapser system of the present invention.

FIG. 16 depicts a cross-sectional view of a jaws assembly of the present invention.

FIGS. 17A-17D depict a distal perspective, a plan end view, a top plan view and a side plan view of a first jaws blade of the present invention.

FIGS. 18A-18D depict a distal perspective, a plan end view, a top plan view and a side plan view of a second jaws blade of the present invention.

FIGS. 19A-19C depict a perspective, a front plan view and a side cross-sectional view, respectively, of the cam assembly of the present invention.

FIG. 20 depicts a perspective view of a cam driver subassembly of the jaws subsystem of the present invention.

FIG. 21 depicts a proximal plan view of a cam driver subassembly of the jaws subsystem of the present invention.

FIGS. 22A-22G depict the method steps of using the cold collapser system of the present invention.

FIG. 23 is a schematic representation of one embodiment of a pneumatic system of the present invention, including gas flow control.

FIG. 24 depicts a method step of using the cold collapser system of the present invention, wherein a stent or medical device is first dipped into a bath of cold material.

FIG. 25 is a perspective view of an embodiment of the cold collapser system of the present invention, including a pre-cooling subsystem separate from the collapsing containment housing.

FIG. 26 is a perspective view of an alternative embodiment of the cold collapser system of the present invention having a pre-cooling subsystem connected to the collapsing containment housing.

FIGS. 27A and 27B are graphs depicting the martensite to austenite phase transformation of nitinol along a temperature range.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in the drawings for purposes of illustration, the present invention is directed to a new system and method for collapsing and/or crimping a stent or medical device to a small diameter for the purpose of loading into a delivery catheter or onto a balloon catheter. The present invention is particularly useful with stents, grafts, tubular prostheses, embolic devices, embolic filters, and embolic retrieval devices. The collapser system and method of the present invention may also be used to crimp or collapse self-expanding and mechanically expandable stents or other medical devices, with or without a drug coating. The text herein and accompanying drawings are generally directed to self-expanding nitinol stents; however, those of ordinary skill in the art will appreciate that the various apparatus and methods described herein may be adapted for use with other devices and materials.
As shown in FIG. 1, the cold collapser system 50 of the present invention includes a containment (housing) subsystem 100, a control subsystem 200 and a cooling subsystem 300. The containment subsystem includes entry ports for connecting to a first air (gas) chiller hose 312 in fluid communication with a first air (gas) chiller 310, and includes a second air (gas) chiller hose 322 in fluid communication with a second air (gas) chiller 320. Each chiller may include or be connected to a moisture remover (dryer) and temperature controller that interface with the control subsystem.
The walls or panels 112, 114 of the containment housing 110 may be formed from a substantially transparent material, such as glass, polycarbonate (Plexiglas™) or other suitable material. The body of the containment housing may be formed from dual layers of the wall material, wherein a gap or spacing 108 is provided between each wall layer, so as to provide contained dry air or other gas to help prevent condensation on the inside and outside of the housing walls (FIGS. 3A, 22A). Alternatively, gas, such as nitrogen or air, at room (ambient) temperature, for example, zero to twenty degrees Celsius (° C.), may be configured to flow through the gaps between the layers in the containment housing walls and discharged to the atmosphere—outside of or within the containment housing. The top of the housing 115 may be secured to the sidewalls by adhesives, screws or other suitable mechanisms. Similarly, each outer sidewall is secured to each inner sidewall by adhesives, screws, dowels or other suitable means. The corners of the sidewalls 108 may be further configured to allow for circulating air between the wall layers. The walls of the containment system may be configured with holes 106 for placement of screws, dowels or other securing devices (FIGS. 3B, 3C).
Referring to FIG. 2, the cover assembly 110 of the cold containment subsystem 100 includes a front wall or panel 112 (FIG. 3B) having an opening or port 102, which may be rectangular or other suitable shape, for insertion and retaining the arm 126 for the mandrel handle 124 (FIG. 7). The front panel of the cover assembly further includes an opening or port 104 for extension of a mandrel 122 so as to allow for positioning of a stent or other medical device (not shown) to be collapsed around the mandrel. The mandrel opening may be circular or other suitable shape and is configured to house a sheath holder (plug) 150 (FIG. 6A) for retaining the mandrel and for substantially preventing cold air or other gas from escaping from the cover assembly. The cover assembly further includes a side panel 14 (FIG. 3C) configured with holes or cut- outs 116, 118 for the first (cold) and second (warm) chiller hoses 312, 322. The top of the cover assembly may be substantially flat so as to allow placement of the electronic control subsystem 200.
As shown in FIG. 4, the cold collapser system 50 of the present invention further includes a base 140 secured to the walls housing. The base allows for securing various mechanisms within the housing to stabilize them during operation. The base has a substantial rectangular portion 141 and a side flange 142 for securing the upper fittings 304, 306 and lower fittings 305, 307 configured to hold the first and second air chiller hoses 312, 322. The base further includes a cutout 144 intended to function as a catch basin for any condensation that may form on the housing 402 of the collapser subsystem 400 (FIG. 7) and drip onto the base.
Referring now to FIGS. 5A, 5B and 5C, the front panel 112 of the housing 110 includes a square (rectangular) hole 102 for slidably retaining the arm 126 of the mandrel subsystem 120. So as to prevent leakage of the insulating air (gas) between the housing walls, a square or other suitable shaped plug 130 is inserted into the aperture for retaining the mandrel arm. The mandrel aperture plug includes a proximal portion 132 sized for substantially sealing the aperture in the outer wall of the housing front panel 112. The mandrel plug further includes a central body portion 134 sized and configured for sealing the gap between the housing walls. In addition, the sheath plug includes a distal portion 136 sized for sealing and fitting within the aperture of the inner wall of the front plate of the housing.
Referring now to FIGS. 6A-6D, the sheath holder 150 of the present invention includes a body 152 having a substantially circular cross-section. The proximal end 154 of the sheath holder is configured for gripping by a human hand including a knurled grip 160 or similar configuration. The body of the sheath holder includes a plurality of vents 158 that are configured for fluidly connecting to the inside of the containment housing 110 at the circular opening (hole) 104 of the front panel 112. The gap 108 between the walls of the front panel is blocked by spacers 138 at either side of the circular opening (FIG. 22A). The distal portion 156 of the sheath holder is adapted for securing within the housing, and may include a lock mechanism 162. The lock mechanism may be configured as is well known to those skilled in the art, such as a peg and groove system.
The distal portion of the sheath holder 150 further includes a cut-out or lumen 164 for allowing passage of the mandrel 122, and is configured with a diameter for retaining the sheath 180 (FIG. 22B). The distal-most portion 166 of the sheath lumen is configured with an expanded diameter so as to retain the flared end 186 of the sheath. The proximal portion 154 of the sheath holder is further configured with a large diameter lumen 168 for venting the air (gas) that passes through the sheath holder apertures 158 from the containment housing 110 to atmosphere. The large diameter lumen further acts as a conduit for the chilling air (gas) that exits the proximal end of the collapser subsystem 400 as the stent (medical device) 170 is cooled to its crimping temperature (FIGS. 22C, 22D). The large diameter lumen further acts to eliminate condensation buildup on the sheath 180 and mandrel proximal end 190, since the relatively dry air (gas) from the containment housing displaces the relatively moist ambient (room) air from the large diameter lumen.
Referring now to FIG. 7, the cold collapser system 50 of the present invention includes an air chilling subsystem 300, a mandrel subsystem 120 and a device collapser (crimping) subsystem 400. The air chilling subsystem includes brackets for removably retaining the chilling air hoses 312 and 322 (FIG. 1). The air hoses are positioned between a first bracket having an upper removal portion 304 and a lower fixed portion 305 secured to the containment base 140. The second bracket includes an upper removal portion 306 and a lower fixed portion 307 secured to the containment base. Each of the brackets includes apertures 308 configured for retaining the chilling air hoses. The chilling subsystem further includes a first (cold) air valve 314 having an inlet air fitting 315 configured to fluidly connect to the first chilling air hose 312. The cooling subsystem further includes a second (warm) air valve 324 having an inlet air fitting 325 configured to connect to the second chilling air hose 322. Each of the cold and warm air valves contain a vent or outlet 318, 328 for purging excess cold and warm air to the atmosphere or within the containment housing 110. In addition, each of the cold air valves include electrical connectors 316, 326 for electrically connecting the valves to fittings 319 and 329 positioned within the support base 146 of the containment subassembly 100. The support base 146 is separated and secured to the containment subsystem base 140 by a plurality of walls or panels 148. The resulting sub-housing allows for the other components of the containment system (FIGS. 12 and 13) to be separated from the chilling, mandrel and jaws subassemblies.
Referring now to FIG. 8, the mandrel subassembly 120 includes the mandrel handle 124, a handle arm 126, a mandrel 122 and a slide mechanism 128, 129. The mandrel handle is ergonomically designed for use by a human hand for grasping the handle so as to move the mandrel arm along the mandrel slide assembly. As the mandrel handle is moved in a longitudinal direction (distal to proximal), the mandrel moves in parallel to the mandrel arm. The mandrel arm is secured to a linear bearing carriage mechanism 128 that is slidably connected to a slide base 129. The distal portion of the 194 of the mandrel is secured to the base mechanism, and may be fixably or removably attached, for example, by a mounting block 196 having a thumbscrew 198. The distal portion 194 of the mandrel has a first outer diameter configured to connect to the base mechanism so as to withstand the torque and stress placed on the mandrel as it slides within the housing. The mandrel is configured with a second (middle) portion 192 having an outer diameter less than the distal portion outer diameter and configured to push the collapsed medical device (stent) into the stent sheath (FIG. 22G).
The proximal portion 190 of the mandrel 122 is configured with a third outer diameter that is less than the outer diameter of the second (middle) mandrel portion 192. The difference between the diameters of the proximal and middle portions of the mandrel may be about 0.005 inches (″) 0.127 millimeters (mm) and about the thickness of the stent wall. The proximal portion is configured for retaining and providing longitudinal support to the stent 170 during loading (FIG. 22B) and collapsing (FIGS. 22E, 22F). The mandrel proximal portion supports the stent, which is rather flexible when cooled and collapsed and subject to sliding frictional forces, as the stent is pushed into the sheath 180 (FIG. 22G).
The cold collapser system 50 of the present invention may be configured for use with a plurality of different mandrels 122 that are designed for use with a variety of sizes of stents or other collapsible medical devices. A suitable outer diameter for the distal portion 196 is 0.125″ (3.175 mm). For example, a stent having a collapsed inner diameter of 0.030″ (0.762 mm) and a collapsed outer diameter of 0.040″ (1.016 mm), the mandrel would have dimensions including a proximal portion 190 outer diameter of 0.029″ (0.7366 mm), a middle portion 192 outer diameter of 0.039″ (0.9906 mm). Similarly, for a stent having a collapsed inner diameter of 0.180″ (4.572 mm) and a collapsed outer diameter of 0.500″ (12.7 mm), the mandrel would have dimensions including a proximal outer diameter of 0.0179″ (0.455 mm) and a middle outer diameter of 0.499″ (12.675 mm). The mandrels may be made from stainless steel, polymers, such as poly-ether-ether-ketone (PEEK) and high-density polyethylene (HDPE), or other suitable materials able to withstand the cold temperatures used in the present invention. The three portions of the mandrel are configured with lengths that will support the length of the stent or other medical device to be collapsed, and the overall length of the mandrel will depend upon the distance between the mandrel holder 196 and the sheath holder 150.
As shown in FIG. 9, the cold collapser system 50 of the present invention includes a thermocouple subassembly 330. The thermocouple assembly includes a thermocouple 332 that may be contained within a protective sheath (not shown) that may be made from stainless steel or other suitable materials able to withstand the cold temperatures used in the cold collapser system. The thermocouple is attached to a housing or holder 334, wherein the thermocouple may be press fit or otherwise secured within an opening of the holder. The housing further includes a thermocouple wire duct (not shown) for retaining a thermocouple wire and leads 335 that electrically connect to the control subassembly 200. The housing of the thermocouple assembly is connected to or formed with a main body 336 having a flange 338 that is configured for slidably mounting onto a linear slide bracket 339 (FIGS. 7 and 12) secured to the support base 146 of the containment subsystem 100.
As shown in FIG. 10, the cold collapser system 50 of the present invention includes a cold air nozzle subassembly 350. The nozzle subassembly includes a cold air nozzle 352 having a proximal end portion 354, a substantially cylindrical body 356 and a distal end portion 358. The proximal end of the nozzle is configured for slidably entering the distal end 408 of the jaws housing 402 through the distal cam assembly 426 (see FIGS. 14A and 15). The cold air nozzle assembly further includes a cold air inlet 360, a defrost (relatively warm, for example, room temperature) gas inlet 362, a mandrel opening 364 and thermocouple openings 368, 369. As shown in FIGS. 11A-11F, the cold air inlet is mounted within a lumen (hole) 370 that is fluidly connected to a cold air plenum 376 so as to provide a path for the chilling air (gas) to pass from the chiller air hoses 312, 322 through the valves 314, 324 into the jaws subassembly 420 via a plurality of cold air holes 375 in the proximal end 354 of the nozzle.
Referring to FIG. 10, a distal end cap 366 is configured to fit on the distal end 358 of the nozzle 352 to secure the nozzle to a mounting bracket 380. The cap is secured to the nozzle using screws that fit into the holes 379 and 378 (FIGS. 11A, 11C). The mounting bracket is configured with a base 382 configured to be slidably secured to a linear slide 384 that may include a linear bearing carriage on a slide base (FIG. 7). The slide base is mounted onto the support base 146 of the cold collapser housing 110. The body 356 of the nozzle is formed from stainless steel, polymer or other suitable material. The mounting bracket and support base are formed from stainless steel, aluminum or other suitable material.
Referring also to FIG. 11D, the defrost air inlet fitting 362 of the cold air nozzle subassembly 350 is fluidly connected to the defrost (insulating) gas (air) nozzle 344 positioned within a wall of the containment housing 110 (FIGS. 12, 13) so as to allow defrost (ambient, relatively warm and dry) air (gas, such as nitrogen) to enter the cold air nozzle 352, the containment housing 110 and the sheath holder 150. The defrost air inlet fitting resides within a port (hole) 372 surrounded by a substantially rectangular cutout 374 (FIG. 11E) in the body 356 of the cold air nozzle so as to support a nut or other device to secure the fitting to the housing. The defrost air inlet fitting is in fluid communication with a lumen 378 that directs the defrost air to the mandrel opening 364 in the cold air nozzle subassembly (FIG. 11D).
Referring to FIGS. 11B, 11F, the proximal end portion 354 of the cold air nozzle 352 is formed with a substantially circular mandrel lumen 364. A tubing segment 390 traverses from the mandrel opening in the proximal end portion to the distal end portion 358 of the cold air nozzle so as to allow the proximal end portion 190 and middle segment 192 of the mandrel 122 to be slidably disposed within the cold air nozzle and to enter into the jaws subassembly 420. The tubing segment further protects the mandrel from the cold air passing through the nozzle. The tubing segment may be held in place by a dowel 392 disposed with a transverse lumen 394 in the nozzle body 356 (FIG. 11D). The thermocouple opening 368 of the nozzle is sized and configured for allowing the thermocouple 332 to be slidably disposed within the cold air nozzle and the jaws subassembly. The end cap 366 is also configured with a lumen 369 for slidably retaining the thermocouple (FIG. 10).
As shown in FIGS. 12 and 13, the cold collapser system 50 of the present invention includes a cooling subsystem 300 and a device collapser (crimping) subsystem 400 having a jaws subassembly 420. The cooling subsystem 300 includes a first (cold) gas (air) chiller hose 312 that is in fluid connection with the first (cold) gas chiller 310 (FIG. 1). The cold gas chiller is designed to provide a very low temperature gas feed, such as about minus 85° C. (for example, from −60° C. to −90° C.). The cold gas chiller hose is fitted on its distal end (within the housing 110) with a fitting 346 that connects to a tubing (not shown) that is in fluid communication with the inlet gas fitting 315 on the cold gas valve 314. In similar fashion, a second (warm) gas (air) hose 322 that is connected to the second (warm) air chiller 320, which is configured to provide low temperature air (gas) feed, such as about minus 20° C. (for example, from −40° C. to +20° C.) The warm gas chiller hose is fitted on its distal end (within the containment housing) with a fitting 348 that connects to a tubing (not shown) that is in fluid communication with the inlet gas fitting 325 on the cold gas valve 324. The desired temperatures of the outlet gases from the chillers may vary with material composition and material thickness. Alternatively, a single cold gas supply source, such as liquid nitrogen, may be used in conjunction with temperature controllers to provide the two temperature gas feeds. The conduit between the chilling air hoses and the air valves may be made of stainless steel, copper tubing, reinforced polymer or other suitable material.
The cold air control valve 314 is configured with an outlet air (gas) fitting 340, and the warm air control valve 324 is configured with an outlet air (gas) fitting 342. The outlet fittings are connected to a “T” fitting (not shown), which is connected via tubing (not shown) to the inlet air port 360 of the cold air nozzle 352. The cold air and warm air valves are switched via electrical connections 316, 326 that are electrically coupled to the control system 200 via conduits (not shown) that are coupled to the inlet connections 319, 329 in the support base 146 of the containment housing 110.
For certain compositions of nickel-titanium or other alloys, it may be desirable to drive the temperature of the material forming the medical device so low that the phase transformation from austenite to martensite is complete—final (M_f), as shown in FIGS. 27A and 27B. Referring to FIG. 24, one method for reducing the temperature of a nitinol stent 170 below minus 90° C., wherein the martensite phase transformation is likely to be complete, is to expose the stent to liquid nitrogen. Liquid nitrogen may be supplied from a storage tank 710 having a fitting 712 for connecting to a conduit (hose, tube or pipe) 714 having an outlet spigot 716. The spigot may be used to fill a vessel 750 having a base 752 and an insulated wall 756. The stent may be dipped into the vessel for a period of time (for example, several seconds to several minutes) to complete the phase transformation from austenite to martensite. Alternatively, the vessel may be filled with solid carbon-dioxide (dry ice) in an alcohol bath (about −40° C.) or filled with other sub-zero degree Celsius materials or mixtures.
As shown in FIG. 25, a liquid nitrogen supply system 700 may be used to pre-cool a stent or other medical device 170 (prior to the step shown in FIG. 22B) to its martensite state. A liquid nitrogen tank 710 may be connected via a valve 712 and a conduit 714 to a flow controller 720 having a control panel (operator interface) 722. The flow controller may be connected to the first (proximal) end 732 of a liquid nitrogen hose 730 having a second (distal) end 734 connected to a pre-cooler containment housing configured with a control panel 746. The distal end 734 of the hose may be supported and fixed to the housing by a bracket 736. The stent or other device to be pre-cooled may be placed in a holder 744 that is removably positioned within an opening 742 in the housing so as to expose the holder and stent to the temperature provided by the liquid nitrogen supply, which may be gaseous as it enters or exits the pre-cooler containment housing 740. As those of ordinary skill in the art will appreciate, various embodiments of the nitrogen system may be configured, including adapting the nitrogen system to feed the cold gas hose 312 and the warm gas hose 322, and providing appropriate temperature and flow controllers to achieve the desired temperatures during the cold collapse process.
Alternatively, and as shown in FIG. 26, the pre-cooler containing housing 740 could be placed directly in front of the mandrel opening 104 (FIG. 2) in the containment housing 110. The stent or other medical device 170 would be placed on the mandrel distal portion 190 (as shown in FIG. 22B) and moved into the pre-cooler containment housing 740. The sheath holder 150 (containing sheath 180) would be secured into the opening 742 in the proximal wall of the pre-cooler containment housing 740, and the pre-cooling stent holder 744 may not be required. The control panel 746 may be used to pre-cool the stent to the desired temperature, for example to bring the material forming the medical device to a temperature where the transformation to the martensite phase is complete. The stent would then be shuttled via the mandrel 122 into the collapser subsystem 400 (FIG. 22D) for warming to the desired collapse temperature (for coated devices) and collapsing of the stent. The functions of the pre-cooling control panel 746, the flow controller 720 and the control panel 722 may be incorporated into the control subsystem 200. In such an embodiment, the cold chiller 310 and hose 312 may not be needed. The stent would be exposed to pre-cooling temperatures ranging, for example, from −90° C. to −150° C. in the pre-cooler containment housing 740, and exposed to temperatures ranging, for example, from 20° C. to −40° C. in the jaws subassembly. This embodiment of the apparatus and method of the present invention also would be used to maintain the martensitic phase of the device material through the collapse process, as shown in FIGS. 22E-22G. This process could also be used for non-coated nitinol (NiTi) stents and other medial devices.
Referring now to FIGS. 14A-14D, the collapser (crimping) subsystem 400 includes a jaws subassembly 420 (FIGS. 15, 16). The collapser subsystem also includes a driver subassembly 450 (FIG. 20), and further includes an activator subassembly 480 (FIG. 21) for opening and closing the jaw blades 430, 440 of the jaws subassembly. The collapser subsystem includes a housing 402 having a proximal end portion 404, a body portion 406 and a distal end portion 408. The body of the housing includes a plurality of apertures (holes) 412 to retain the linear bearings 422 of the jaws subassembly. Both the proximal end and the distal end portions of the housing include an end cap 410 configured for retaining the cam assemblies 424, 426 and radial bearings 425, 427. The housing is further configured with a proximal flat portion 414 and distal flat portion 416 configured for mounting the collapser subsystem housing to the support base 146 of the containment housing 110. The flat portions or cutouts include one or more holes 418 for screws or dowels to secure the jaws housing to the containment support base.
As shown in FIGS. 15 and 16, the jaws subassembly 420 includes a plurality of jaw blades 430, 440 and linear bearings 422 that are in mechanical communication with the proximal cam assembly 424 and distal cam assembly 426. The cam assemblies fit within proximal radial bearing 425 and distal radial bearing 427. The cam assemblies include flanges 472 that are configured to mechanically engage slots 438, 439, 448, 449 within proximal and distal ends of the jaw blades. The jaw blades may be formed from stainless steel, aluminum, polymer or other suitable material, and may be provided with a nickel or similar coating that is polished to reduce damage to any coating on the stent or medical device. The jaws assembly housing 402 may be formed from stainless steel, aluminum, polymer or other suitable material. The cam assembly, linear bearings and radial bearings are formed from stainless steel, aluminum, polymer or other suitable material.
Referring to FIGS. 17A-17D and 18A-18D, there are two separate blade assemblies 430 and 440 within the jaws assembly 420. As shown in FIGS. 17A-17D, the first jaw blade 430 includes two holes or apertures 432 in its proximal portion and its distal portion. Each hole is configured to retain a linear bearing 422. In addition, two grooves (semi-circular cutouts) 434 are configured in the proximal portion and distal portion of the blade so that as the jaw blades collapse the linear bearings from the other jaw blades fit within the grooves. The linear bearing holes 432 of the first jaw blade 430 are positioned outside (proximal or distal) of the grooves 434. The jaw blades are further configured with proximal and distal slots 438, 439 for engaging the inside portion of the flange 472 of the cam assemblies 424, 426. Thus, as each cam assembly rotates, the flanges rotate the jaw blades about a center axis of the collapser subsystem housing 402. Each blade is beveled on its inside portion 436 at an angle 435 of approximately forty-five degrees. This beveling allows the blades to slide against each other as the cam assemblies rotate. As shown in FIGS. 18A-18D, the second jaw blade 440 is configured similar to the first jaw blade 430; however, the apertures 442 for the linear bearings are on the inside (medial) portion of the jaw blade relative to the grooves 444 in the jaw blade body. The second jaw blades are also configured with proximal and distal slots 448, 449 for engaging the flanges 472 on the cam assemblies. The second jaw is also configured with a beveled edge 446 having a similar angle 445 as the first jaw edge 436 and angle 435.
Referring now to FIGS. 19A-19C, the proximal cam assembly 424 is substantially cylindrical, having a thickness in its body 460 substantially less than the diameter of the cam assembly. The distal cam assembly 426 is configured the same as the proximal cam assembly. Each cam assembly is substantially toroidal (donut-shaped), having a central lumen 462 within which the sheath holder 150 resides (proximal cam assembly), the cold air nozzle 352 resides (distal cam assembly) and the mandrel 122 passes through (FIG. 22A). Each cam assembly includes an outside face 464 and an inside face 466. A plurality of flanges 472 protrude from the inside face and are substantially flush 470 with the outer face 464. The body of each cam assembly further includes a plurality of holes 474 spaced between the flanges for accepting screws or other securing mechanisms to attach each cam assembly to the drivers 454, 456 (FIG. 20).
Referring now to FIGS. 20 and 21, the collapser subsystem 400 includes a driver subassembly 450 and an activator subassembly 480. A proximal driver 454 having a upper circular shaped body with a lower rectangular flange is connected to a distal driver 456 by a link bar 458. As heretofore described, the drivers are connected to the cam assemblies 424, 426 via screws, dowels, bolts or other mechanisms through holes or apertures 459 in the driver assemblies and the holes 474 in the cam assemblies. The link bar 458 is connected via a hinge mechanism 486 that is mechanically connected to a drive shaft 484 operated by an air cylinder 482. The air cylinder is connected to the containment housing 110 by a trunnion bracket 485 secured to the support base 146 of the containment subsystem 100. A spring mechanism 488 is connected to the drive shaft and hinge mechanism to limit the force that can be applied to the drivers and cam assemblies by the air cylinder.
J As the air cylinder 482 pushes the drive shaft 484 in a transverse direction, the link bar 458 rotates about the axis of the collapser housing 402. Rotation of the link bar causes the proximal driver 454 and the distal driver 456 to rotate in a radial fashion. As the drivers rotate in a radial direction, the linkage bar 458 between the drivers and the cam assemblies 424, 426 cause the cam assemblies to rotate the jaw blades 430 and 440 as the cam flanges 472 engage the slots 438, 439, 448, 449 in the proximal and distal ends of the jaw blades. As the cam assemblies rotate within the radial bearings 425, 427, the jaw blades begin to move (collapse) in an iris fashion. The jaw blades are longitudinally held in place by the linear bearings 422. As the jaw blades rotate, they narrow or widen the lumen 490 within the jaws assembly 420. As the beveled edges 436, 446 of the jaw blades move closer to each other, they slide point to point so as to collapse the stent or medical device during the collapsing procedure (FIGS. 22F, 22G).
As heretofore described, each first blade 430 is configured with a beveled edge 436 having a first side and a second side joining at a first tip (FIGS. 17A-17D). Similarly, each second blade 440 is configured with a beveled edge 446 having a first side and a second side joining at a second tip. As shown in FIGS. 15 and 16, at least two (for example, four) of the first blades and at least two of the second blades (for example, four) are positioned and arranged within the housing 402 to move relative to each other from a first position, such that the tips of the first and second tips offset from each other by a first distance, forming a lumen 490 between the blade tips. Radial motion of the linking mechanism (the driver subassembly 450 and the activator subassembly 480) causes the first and second blade tips to move from the first position that forms a lumen within the housing having a first diameter to a second position that causes first and second tips to form a lumen having a second diameter. At the second position, the first blades and the tips of the second blades are offset from each other by a second distance different than the first distance, such that the diameter of the lumen narrows. The stent 170 having an expanded diameter is placed into the lumen of the jaws assembly 420 when the lumen is at a large (open) diameter. When the linking mechanism is rotated, the first and second blades form a lumen of a smaller (closed) diameter, wherein the stent is collapsed from the expanded diameter to substantially the smaller diameter of the lumen in the jaws assembly.
Referring now to FIGS. 22A-22G, the method of use of the cold stent collapse system 50 of the present invention is shown in several discrete steps. Of course, the system is operated on a substantially continuous basis, including automatic and manual operation of the pneumatic control system (FIG. 23). For example, the operator of the cold collapser system ensures that valves for the air and other gas (such as nitrogen) lines are open and set at the appropriate pressures and flow for the air chillers 310, 320 within the chilling subsystem 300. Similarly, the operator turns on all power strips and switches to the temperature controllers and other electronics of the control subsystem 200. The system may be operated in a “pre-cooling” phase (initial cooling from room temperature) prior to an actual collapsing (crimping) procedure. The following method description is in relation to collapsing (crimping) a stent, but as those of ordinary skill in the art will appreciate, the steps may be varied for other suitable medical devices and variations of the cold collapser system of the present invention. In addition, the collapser subsystem 400 may be utilized without the cooling (chilling) subsystem 300.
As shown in FIG. 22A, the collapser subsystem 400 starts out with the collapser jaw blades 430, 440 in an open position with the mandrel 122 and mandrel handle in their retracted (distal) position. The proximal end 190 of the mandrel extends through the jaws subassembly 420 and into the sheath holder 150. The thermocouple subsystem 330 is positioned such that the thermocouple 332 resides within the open area (lumen) 490 of the jaws subassembly. The nozzle subsystem 350 is positioned so that the nozzle 352 is in its proximal position inside the distal end of the jaws subassembly. The cold air subsystem 300 (shown schematically in FIGS. 22A-22G) is set such that the cold air valve 314 is open to a cold air conduit 395 that is in fluid connection to the inlet fitting 360 of the nozzle subsystem. At this point, the pneumatic and electronic control systems are set such that cold air flow (for example, −85° C.) from the cold air chiller 310 and warm air flow (for example, 0° C.) from the warm air chiller 320 are at a low flow, for example 1.2 standard cubic feet per minute (SCFM). This is considered the system standby position, wherein the warm air flow exhausts into the containment housing 110 through its exhaust port 328 to cool the containment area below room temperature, thereby also pre-cooling the collapser subsystem 400.
As shown in FIG. 22B, to begin the process of loading the stent 170 onto the mandrel 122, the sheath holder 150 is removed from the collapser subsystem 400. If not preloaded, then the stent sheath 180 is placed into the sheath holder distal lumen 164, such that the body 184 of the stent sheath resides in the distal lumen and the flared end 186 of the sheath is positioned at the widened aperture 166 at the distal end of the lumen. Once the sheath holder is removed from the collapser subsystem, the mandrel handle 124 is pulled out approximately halfway of its fullest extended proximal position. As the handle is extended proximally, the mandrel distal portion 190 also extends beyond the front wall 112 of the housing. At this point, the cold air nozzle 352 and thermocouple 332 are in place and the cold air flow is still at a low flow rate.
Referring now to FIG. 22C, the stent or other medical device 170 is placed on the proximal portion 190 of the mandrel 122, and the mandrel handle 124 is moved to its most distal position such that the mandrel and stent are moved distally, wherein the stent is positioned within the jaws housing lumen 490 and proximate the jaw blades. The mandrel middle portion 192 is positioned distal to the proximal end of the nozzle 352 so that the stent is crimped to the diameter of the mandrel's proximal portion. The stent may be lubricated (for example, with silicone—DOW 360) to reduce damage to any coating during the process of placing the stent on the mandrel, crimping and insertion into the sheath 180. As shown in FIGS. 24-26, the stent may be pre-cooled with liquid nitrogen or other sub-zero material.
The operator then pushes the “start” button 222 on the control housing 202, and the cold air (for example, −85° C.) flow rate increases (for example, to 2.4 SCFM) into the jaws chamber 490. The operator can monitor the temperature within the jaws chamber by viewing the display 252 on the control housing (FIG. 1). The cold air flow moves from the cold air hose 312 through the cold air flow valve 314 via fitting 340 (and the “T” junction) into the cold air nozzle 352 via fitting 360 and through cold air exits 375 (FIG. 11F) and into the jaws chamber. This cold air flow continues at a high rate of flow until the thermocouple 332 indicates that the internal temperature of the jaws chamber is at a desired temperature (for example, −60° C.), such that the temperature of the material forming the stent is lowered below the austenite phase transformation temperature (A_s) (FIGS. 27A, 27B) and perhaps lowered until the martensite phase transformation of the stent alloy is completed (M_f)—so as to substantially eliminate the radial force exerted by the stent on the collapsing apparatus.
As shown in FIG. 22D, once the thermocouple 332 indicates that the internal temperature of the jaws chamber 490 has been at the desired temperature (for example, −60° C.) for several seconds or minutes, the cold air valve 314 switches to exhaust the “cold air” flow (for example, −85° C.) into the containment housing 110. The warm air valve 324 switches from its exhaust position to direct “warm air” (for example, 0° C.) at a high flow rate (for example, at 2.4 SCFM) from the warm air hose 322 through the warm air flow valve exit fitting 342 into the cold air nozzle 352 so as to enter the jaws chamber 490. The warm air continues to flow into the jaws chamber until the thermocouple indicates a desired temperature (for example, −20° C.) for a sufficient time to warm the stent coating to a temperature that will reduce cracking of the coating (for example, several seconds or minutes). This warming temperature is chosen so that the temperature of the stent is still below the beginning of austenite (A_s) phase transformation and the drug/polymer coating on the stent is at a non-brittle temperature for collapsing the stent.
Referring to FIG. 22E, once the internal temperature of the collapser chamber 490 of the jaws subassembly 420 reaches a desired temperature (for example, −20° C.) and after a delay of several seconds to several minutes, the cold air nozzle subassembly 350 moves in a distal direction such that the proximal end 354 of the cold air nozzle 352 is distal of the jaw blades 430, 440 so as to not interfere with the collapsing (crimping) process. Likewise, the thermocouple assembly 330 is moved in a distal direction such that the thermocouple 332 is moved distal of the distal end of the jaws and within the nozzle so as to not interfere with the movement of the jaw blades. The electronic and pneumatic subsystems activate the cam assemblies 424, 426 at the ends of the jaws subassembly 400 so as to collapse the jaw blades around the stent 170.
As shown in FIG. 22F, the stent 170 is collapsed by movement of the jaw blades 430, 440 to have an inner diameter substantially the same as the diameter of the mandrel distal portion 190 that resides within the collapser chamber 490. The outer diameter of the stent is collapsed to a position such that it has essentially the same diameter as the middle portion 192 of the mandrel 122 and slightly smaller than or essentially the same diameter as the inner diameter of the body 184 of the sheath 180. Note that the mandrel middle portion is distal to the proximal end of the nozzle 352 so that the stent is protected against collapsing onto the mandrel middle portion and damaging the jaws subsystem 420 and the stent.
As shown in FIG. 22G, the next step is to fully extend the mandrel handle 124 to its proximal most position, causing the stent 170 and middle portion 192 of the mandrel 122 to move towards the sheath holder 150. The full extension of the handle and mandrel moves the middle portion of the mandrel against the distal portion of the stent so as to push the stent through the flared distal end 186 of the sheath 180 and into the sheath body 184. Once the stent has been moved into the sheath, the sheath holder is removed from the collapser subsystem 400, and the sheath is removed from the sheath holder. Thereafter, the sheath containing the stent is directed to the next portion of the catheter assembly process.
The operator then pushes the “reset” button 242 on the control housing 202, causing the jaw blades 430, 440 to open. The nozzle subassembly 350 and thermocouple subassembly 330 move in a proximal direction, as shown in FIG. 22A. The warm air valve 314 is switched to its exhaust position at its low flow rate (for example, at 1.2 SCFM), and the cold air valve 312 is switched to direct its flow to the nozzle 352 at its low flow rate (for example, at 1.2 SCFM). The cold collapser system 50 of the present invention is then ready to collapse its next stent when the operator pushes the “start” button 222. An emergency stop button 212 may be provided to disconnect power from all system components in the event that some component or wiring becomes damaged, thus compromising electrical insulation and operator safety.
Referring now to FIG. 23, the pneumatic system 500 of the cold collapser system 50 of the present invention includes the base 520 of the flow control subsystem housing 202, the containment housing base 140 and the containment housing support base 146. House gas or air, for example, nitrogen at eighty to one-hundred and fifty pounds per square inch (psi), is provided by connection to a first inlet fitting 522. The house air is connected to a first air dryer 524, available from FTS SYSTEMS, Model AD80. The air dryer connects to the flow control base through a second fitting 526, which is connected to a pressure regulator 530, for example, an eighty psi non-adjustable regulator. The air flow then splits into a first flow line 532 and a second flow line 534. The first flow line connects to a first control valve 536, which directs the flow to a first (high flow) controller 540 connected to the high flow meter 232 and to a second (low flow) controller 542 connected to the low flow control meter 236. Both the low flow line and the high flow line include check valves 544, 546 that are connected to an outlet fitting 548.
As further shown in FIG. 23, the outlet fitting 548 from the flow control box is connected to the first cold chiller 310 (FTS SYSTEMS XR2-851), which is connected to the first cold gas hose 312 and cold gas control valve 314. A second house gas fitting 550 is connected to a second (warm) air dryer 552 that is connected to a warm air flow controller 554. The warm air flow controller feeds the second (warm) chiller 320 (FTS SYSTEMS XR2-A51), which is connected to the second cold gas hose 322 and the warm gas valve 324. The outlets from the cold control valve and the warm control valve are connected to a “T” junction 556 that connects to the fitting 360 on the cold collapser nozzle 352.
The containment housing support base 146 includes a house air inlet fitting 560 and control valve connected in the fluid line to a pressure regulator 562 (for example, locked at sixty psi) that is connected to a main control valve 564 that is connected to a solenoid-operated control valve 566 also connected to the second flow line 534 from the flow control base 520. The house air flow line is further connected to a control valve 570 connected to the collapse cylinder 482. A cold gas nozzle control valve 580 is connected to the thermocouple slide cylinder 582 and the nozzle slide cylinder 584. The inlet house air is further connected to the mandrel defrost nozzle 362. The system is configured with several flow and delay adjustments 590.
While a particular form of the invention has been illustrated and described, it will also be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited except by the appended claims.

Claims

1. A system for collapsing a device, comprising:

a first cold gas source;

a second cold gas source; and

a jaws subassembly in fluid communication with the first cold gas source and the second cold gas source.

2. The collapsing system of claim 1, further comprising a nozzle subassembly in fluid communication with the first cold gas source and the second cold gas source, the nozzle subassembly being positioned proximate the jaws subassembly.

3. The collapsing system of claim 2, further comprising a mandrel subassembly having a mandrel slidably disposed within a portion of the jaws subassembly and a portion of the nozzle subassembly.

4. The collapsing system of claim 3, further comprising a containment housing having a proximal wall, wherein the proximal wall is configured to slidably retain an arm connected to the mandrel.

5. The collapsing system of claim 4, wherein the proximal wall is configured with an aperture for removably retaining a sheath holder configured to retain a sheath, wherein a proximal portion of the mandrel passes into the sheath and sheath holder when the arm of the mandrel subassembly is moved in a proximal direction, and wherein the mandrel is configured with a middle portion having a diameter larger than a diameter of the proximal portion of the mandrel.

6. The collapsing system of claim 5, further comprising a thermocouple subassembly having a thermocouple slidably disposed within a portion of the nozzle subassembly.

7. The collapsing system of claim 1, wherein the first cold gas source includes a first gas supply for providing gas having a temperature from minus 60° C. to minus 90° C., and the second cold gas source includes a second gas supply for providing gas having a temperature from 20° C. to minus 40° C.

8. The collapsing system of claim 7, further comprising a third cold gas source including a-third gas supply for providing gas having a temperature from minus 90° C. to minus 150° C.

9. The collapsing system of claim 8, wherein the third gas supply includes liquid nitrogen.

10. The collapsing system of claim 1, wherein the first cold gas source and the second cold gas source are fed from a common gas supply so as to provide the first cold gas source with gas having a temperature from minus 60° C. to minus 150° C., and to provide the second cold gas source with gas having a temperature from 20° C. to minus 40° C.

11. The collapsing system of claim 1, further comprising:

a nozzle subassembly in fluid communication with the second cold gas source having a gas supply for providing gas having a temperature from 20° C. to minus 40° C., the nozzle subassembly being positioned proximate the jaws subassembly; and

a mandrel subassembly having a mandrel slidably disposed within a portion of the jaws subassembly and a portion of the nozzle subassembly, and further configured to extend into a containment housing configured for exposing a proximal portion of the mandrel to the first cold gas source having a first gas supply for providing gas having a temperature from minus 60° C. to minus 150° C.

12. The collapsing system of claim 5, further comprising a third gas source having a third gas supply for providing gas at room temperature, wherein the third gas source is configured to circulate the room temperature gas within outer and inner walls of the containment housing.

13. The collapsing system of claim 1, wherein the jaws subassembly includes at least two first blades each having a first end and a second end, each first blade having at least one aperture and at least one groove, and wherein the jaws subassembly includes at least two second blades each having a first end and a second end, each second blade having at least one aperture and at least one groove.

14. The collapsing system of claim 13, wherein the jaws subassembly further includes a proximal driver and a distal driver linked together and configured to engage the first ends and the second ends of each first blade and each second blade.

15. The collapsing system of claim 14, wherein the jaws subassembly further includes a plurality of linear bearings disposed within the apertures of the first blades and the apertures of the second blades, and wherein the grooves of the first blades are positioned to accept the linear bearings of the second blades and the grooves of the second blades are positioned to accept the linear bearings of the first blades.

16. A method for collapsing a device, comprising:

providing a device having a first diameter;

providing a jaws subassembly configured for retaining the device;

providing a first gas at a first temperature into the jaws subassembly;

providing a second gas at a second temperature into the jaws subassembly; and

actuating the jaws subassembly so as to collapse the device from the first diameter to a second diameter.

17. The collapsing method of claim 16, further comprising:

directing the first gas to a nozzle subassembly so as to introduce the first gas into the jaws subassembly;

directing the second gas to the nozzle subassembly so as to introduce the second gas into the jaws subassembly;

providing a mandrel subassembly having a mandrel slidably disposed within a portion of the jaws subassembly and a portion of the nozzle subassembly;

providing a containment housing having a proximal wall, wherein the proximal wall is configured to slidably retain an arm connected to the mandrel, wherein the proximal wall is configured with an aperture for removably retaining a sheath holder configured to retain a sheath, wherein a proximal portion of the mandrel passes into the sheath and sheath holder when the arm of the mandrel subassembly is moved in a proximal direction, and wherein the mandrel is configured with a middle portion having a diameter larger than a diameter of the proximal portion of the mandrel; and

prior to actuating the jaws subassembly, placing the device configured in its first diameter on the proximal portion of the mandrel.

18. The collapsing method of claim 17, further comprising moving the arm in a proximal direction so as to move the device in its second diameter into the sheath.

19. The collapsing method of claim 16, wherein providing a first gas includes providing the first gas at a temperature from minus 60° C. to minus 90° C., and wherein providing a second gas includes providing the second gas at a temperature from 20° C. to minus 40° C.

20. The collapsing method of claim 19, further comprising, prior to providing a first gas at a first temperature, exposing the device in its first diameter to a third gas at a temperature from minus 90° C. to minus 150° C.

21. The collapsing method of claim 16, wherein providing a first gas includes providing the first gas at a temperature from minus 90° C. to minus 150° C., and wherein providing a second gas includes providing the second gas at a temperature from 20° C. to minus 40° C.

22. An assembly for collapsing a device, comprising:

at least two first blades each having a proximal end having a slot and a distal end having a slot, each first blade having a proximal aperture, a distal aperture, a proximal groove and a distal groove, wherein the proximal aperture is positioned proximal the proximal groove and the distal aperture is positioned distal the distal groove; and

at least two second blades each having a proximal end having a slot and a distal end having a slot, each second blade having a proximal aperture, a distal aperture, a proximal groove and a distal groove, wherein the proximal aperture of the second blade is positioned distal the proximal groove and the distal aperture of the second blade is positioned proximal the distal groove.

23. The collapsing assembly of claim 22, further comprising a plurality of linear bearings disposed within the apertures of the first blades and the apertures of the second blades, wherein the grooves of the first blades are positioned and configured to accept the linear bearings of the second blades and the grooves of the second blades are positioned and configured to accept the linear bearings of the first blades.

24. The collapsing assembly of claim 23, further comprising:

a housing having a proximal end having a proximal radial bearing and a distal end having a distal radial bearing, the housing further having a plurality of apertures configured to retain the linear bearings;

a proximal cam assembly configured to be rotatably secured within the proximal radial bearing and configured to engage the proximal end slots of each first blade and each second blade;

a distal cam assembly configured to be rotatably secured within the distal radial bearing and configured to engage the distal end slots of each first blade and each second blade;

a proximal driver operatively connected to the proximal cam assembly;

a distal driver operatively connected to the distal cam assembly; and

a linking mechanism connected to the proximal driver and the distal driver.

25. The collapsing assembly of claim 24, wherein each first blade is configured with a beveled edge having a first side and a second side joining at a first tip, wherein each second blade is configured with a beveled edge, having a first side and a second side joining at a second tip, and wherein each first blade and each second blade are positioned within the housing to move relative to each other from a first position with the first and second tips offset from each other by a first distance, to a second position with the first and second tips offset from each other by a second distance different than the first distance, such that radial motion of the linking mechanism causes the first and second tips to move from the first position that forms a lumen within the housing having a first diameter to the second position that causes first and second tips to form a lumen having a second diameter.

26. The collapsing assembly of claim 25, wherein each blade is formed from stainless steel, plated with nickel and polished to a substantially defect free surface.

27. A method for collapsing a device, comprising:

providing at least two first blades each having a proximal end having a slot and a distal end having a slot, each first blade having a proximal aperture, a distal aperture, a proximal groove and a distal groove, wherein the proximal aperture is positioned proximal the proximal groove and the distal aperture is positioned distal the distal groove;

providing at least two second blades each having a proximal end having a slot and a distal end having a slot, each second blade having a proximal aperture, a distal aperture, a proximal groove and a distal groove, wherein the proximal aperture of the second blade is positioned distal the proximal groove and the distal aperture of the second blade is positioned proximal the distal groove;

providing a plurality of linear bearings disposed within the apertures of the first blades and the apertures of the second blades, wherein the grooves of the first blades are positioned and configured to accept the linear bearings of the second blades and the grooves of the second blades are positioned and configured to accept the linear bearings of the first blades;

providing a housing having a proximal end having a proximal radial bearing and a distal end having a distal radial bearing, the housing further having a plurality of apertures configured to retain the linear bearings;

providing a proximal cam assembly configured to be rotatably secured within the proximal radial bearing and configured to engage the proximal end slots of each first blade and each second blade;

providing a distal cam assembly configured to be rotatably secured within the distal radial bearing and configured to engage the distal end slots of each first blade and each second blade;

providing a proximal driver operatively connected to the proximal cam assembly;

providing a distal driver operatively connected to the distal cam assembly;

providing a linking mechanism connected to the proximal driver and the distal driver;

wherein each first blade is configured with a beveled edge having a first side and a second side joining at a first tip, wherein each second blade is configured with a beveled edge having a first side and a second side joining at a second tip, and wherein each first blade and each second blade are positioned within the housing to move relative to each other from a first position with the first and second tips offset from each other by a first distance, to a second position with the first and second tips offset from each other by a second distance different than the first distance, such that radial motion of the linking mechanism causes the first and second tips to move from the first position that forms a lumen within the housing having a first diameter to the second position that causes first and second tips to form a lumen having a second diameter;

placing a device having an expanded diameter into the housing having a lumen at a first diameter; and

rotating the linking mechanism so that the first and second blades form a lumen of a second diameter, wherein the device is collapsed from the expanded diameter to substantially the second diameter.