Abstract:
A device for providing a fluid to a target tissue region of a body vessel is described. The device includes an elongate member having a lumen to receive a fluid, and a structure deployable from a distal portion of the elongate member to channel blood flowing in the vessel. Also described are a method of, and a system for, providing a fluid to a target tissue region inside a body.

Description:
TECHNICAL FIELD  
       [0001]     This invention relates to medical devices, and more particularly to local cooling devices.  
       BACKGROUND  
       [0002]     Myocardial ischemia, and in severe cases acute myocardial infarction (AMI), can occur when there is inadequate blood circulation to the myocardium due to coronary artery disease. Evidence suggests that early reperfusion of blood into the heart, after removing a blockage to blood flow, reduces damage to the myocardium. However, the reestablishment of blood flow into the heart may cause a reperfusion injury to occur. Reperfusion injury is believed to be due to the build up of waste products on the myocardium during the time blood flow was inadequate and the reaction of these waste products with oxygen in the blood when normal blood flow is reestablished. It is possible to reduce reperfusion injury to the myocardium by cooling the myocardial tissue prior to reperfusion. Mild cooling of the myocardial tissue to a temperature between 28 and 36 degrees Celsius provides a protective effect, likely by the reduction in the rate of chemical reactions and the reduction of tissue activity and associated metabolic demands.  
         [0003]     Local cooling is a site specific, temperature-reducing procedure that affects the cascade of events controlling the future health of the arterial wall that was recently damaged by a blockage in the blood stream. Emergency room procedures may include post-angioplasty local cooling of the lesion site. This additional procedure after dilating the lesion and re-opening the vessel is beneficial because clinical data has also shown that cooling the arterial wall just after angioplasty reduces restenosis or re-clogging of the artery. These outcomes can affect the long-term cost of treating the patient. However, short-term costs and ease of use are also important considerations.  
         [0004]     Current technologies utilized in local cooling procedures vary widely. One method of cooling myocardial tissue is to place an ice pack over the patient&#39;s heart. Another method involves puncturing the pericardium and providing cooled fluid to a reservoir inserted into the pericardial space near the targeted myocardial tissue. Cooling of the myocardial tissue may also be accomplished by perfusing the target tissue with cooled solutions. Frequently, blood is taken from the angioplasty entry site (usually the groin), cooled outside the body, and then re-introduced into the patient, cooling the entire body. This approach is slow, due to requirements of cooling the whole body. In addition, the following re-elevation of the body temperature may require in excess of an hour. Cooling the blood requires a costly heat-exchanger, including the plumbing to transport blood from the patient to heat-exchanger and back. Cooling balloons present their own problems. Utilization of this cooling technology requires a cold flow of inflation media to the balloon and back. This is accomplished using complicated, multiple lumen catheter shafts. An external cold media is slowly pumped through the catheter at a predetermined flow rate, to the dilating pressure level. This is neither a simple nor low cost task. In addition, with perfusing balloons, the perfusion rate is often so high, that without a very large orifice to deliver the cold media, jetting of the media can occur and put the vessel at risk for further damage.  
         [0005]     Direct injection of cold media often has little impact. Without the capability to hold the temperature at the desired target for an extended period, there is often no effect or benefit from the injection of cold media. Although injection of large amounts of cold media can extend the temperature reduction, this may lead to additional complications. When the flow of cold media is stopped, the arterial branch infused with the media may be shocked by the change. This can cause spasm or other reactions, and damage to the vessel.  
       SUMMARY  
       [0006]     Overcoming the problems associated with cooling a local area leads to the requirements of a device that is preferably low-cost, easy to use, simple, capable of maintaining blood flow during the reduced temperature timeframe, capable of utilizing multiple types of cold media, low profile, and easy to manufacture.  
         [0007]     In one aspect, a device for providing a fluid to a target tissue region of a body vessel is described. The device includes an elongate member having a lumen extending longitudinally therethrough from an entry port near a proximal end and to at least one exit port near a distal end of the elongate member, the member being adapted to receive a fluid into the entry port so that the fluid exits the at least one exit port and into a region of the vessel near a target tissue region. The device also includes a structure deployable from a distal portion of the elongate member, the deployable structure being adapted, when deployed, to channel blood flowing in the vessel and substantially isolate the blood flowing through the vessel from the region within the vessel near the target tissue region.  
         [0008]     In another aspect, the device includes a structure deployable from a distal portion of the elongate member, the deployable structure being adapted, when deployed, to channel blood flowing in the vessel such that substantially all of the blood flowing through the vessel flows through the deployable structure. The device also includes an elongate member having a lumen extending longitudinally therethrough from an entry port near a proximal end and to at least one exit port near a distal end of the elongate member, the member being adapted to receive a fluid into the entry port so that the fluid exits the at least one exit port and into the interior of the deployable structure deployed in a vessel near a target tissue region.  
         [0009]     In general, the distal end of the device is advancable through a body vessel to the target tissue region when the structure is in a non-deployed state. Likewise, the distal end of the device cannot be advanced through the body when the structure is in a deployed state. Usually, the proximal end of the elongate body remains outside the body when the distal end of the elongate body is positioned near the target tissue region.  
         [0010]     The device may include a wire running from near the proximal end of the elongate member to a point of attachment to the structure, and wherein the structure is deployed from a distal portion of the elongate member by advancing the wire in a distal direction.  
         [0011]     The device may include a wire loop and a blood channeler having a generally tubular shape. The wire loop includes a shape memory material. The blood channeler is adhesively bonded or welded to the wire loop. The blood channeler may be formed from nylon, PET, Pebax, POC, polyurethane, PTFE, or other biocompatible polymer. Alternatively, the blood channeler may include a mono-layer polymer material, or a layer of nano-laminates.  
         [0012]     Variously, the fluid exits the lumen distally of the wire loop and outside the blood channeler, or the lumen extends distally of the wire loop and wraps around the outside of the deployable structure. The device may also include filter material attached to the outside of the distal end of the blood channeler, and lines attached to the filter material such that material collected by the filter material is retained by the filter material when the deployable structure is retracted. The lumen may have a perfusion section with multiple exit ports allowing fluid flow from the lumen into the blood channeled through the interior of the deployable structure.  
         [0013]     Alternatively, the deployable structure may include an inflatable blood channeler. Fluid from the lumen may be able to pass into the inside of the inflatable blood channeler, and pass from the inside of the inflatable blood channeler into the blood being channeled through the deployable structure. The inflatable blood channeler may be made from nylon, PET, Pebax, POC, polyurethane, PTFE, or other biocompatible polymer. Alternatively, the deployable structure includes an expandable, non-inflatable material. The expandable, non-inflatable material may include a mono-layer polymer, or circumferential rings comprising a shape memory material. The shape memory material may be a polymer, or nitinol. The deployable structure may be self expanding, and may expand upon application of fluid pressure from the lumen, or upon application of cooled fluid from the lumen.  
         [0014]     In another aspect, a method of providing a fluid to a target tissue region inside a body is described. The method includes introducing the distal end of a device as described above into a region of a body vessel near a target tissue region in a body vessel, deploying a deployable structure from a distal portion of the elongate member, and passing fluid through a lumen to at least one exit port located near the target tissue region.  
         [0015]     The deployable structure may be adapted to channel blood flowing in a body vessel and substantially isolate the blood flowing through the vessel from the target tissue region, and wherein the fluid passes from the lumen such that the target tissue region substantially receives only the fluid provided through the lumen while blood continues to flow through the deployable structure and past the target tissue region. Alternatively, deployable structure may be adapted such that substantially all of the blood flowing through the vessel near the target tissue region flows through the deployable structure, and wherein the fluid passes from the lumen into the blood passing through the deployable structure near the target tissue region.  
         [0016]     The deployable structure may include an inflatable balloon. The target tissue region may be located in a coronary artery. The method may include trapping material dislodged by the fluid such that the trapped material does not enter the body vessel blood flow. The fluid may be a cooled fluid, may include a drug, or may be a cooled fluid and the temperature at the target tissue region may be maintained for an extended period within a target temperature range.  
         [0017]     In another aspect, a system for delivering fluid to a target tissue region inside the body is described including a device and structure such as described above, and a control system that controls the amount of fluid provided to the lumen and out of the exit port near the target tissue region. The system may deliver a fluid including a drug to the target tissue region, or may deliver cooled fluid to the target tissue region to maintain the target region at a temperature that is below normal internal human body temperature.  
         [0018]     In another aspect, a process including diverting substantially all of the blood flowing through a body vessel from a target region inside a body such that the diverted blood does not exit the body, and infusing a fluid from outside a body to treat the target region is described.  
         [0019]     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
     
    
     DESCRIPTION OF DRAWINGS  
       [0020]      FIG. 1  is a side perspective view of one embodiment of a local cooling device, deployed in a vessel.  
         [0021]      FIG. 2  is a side perspective view of one embodiment of a local cooling device, shown undeployed.  
         [0022]      FIG. 3  is a part longitudinal cross-section and part perspective view of a close up of the distal end of the local cooling device of  FIG. 1  in a deployed state.  
         [0023]      FIG. 4  is a cross-section of  FIG. 3  taken along the cut-lines  4 - 4  in  FIG. 3 .  
         [0024]      FIG. 5  is a perspective view of a distal end of one embodiment of a local cooling device.  
         [0025]      FIG. 6  is a perspective view of a distal end of one embodiment of local cooling device.  
         [0026]      FIG. 7  is a cross-sectional view of a portion of the cooling device of  FIG. 6  near the distal end of the cooling device.  
         [0027]      FIG. 8  is a perspective view of a distal end of one embodiment of local cooling device.  
         [0028]      FIG. 9  is a perspective view of a distal end of one embodiment of local cooling device.  
         [0029]     FIG  10  is a cross-section of  FIG. 8  taken along the cut-lines  9 - 9  in  FIG. 8 .  
         [0030]      FIG. 11  is a diagram of a side view of a proximal end of a local cooling device used to cool a target tissue region and a control system connected to the proximal end of the local cooling device, the control system shown in block diagram. 
     
    
       [0031]     Like reference symbols in the various drawings indicate like elements.  
       DETAILED DESCRIPTION  
       [0032]      FIGS. 1, 2 ,  3 , and  4  show one embodiment of a local cooling device  10 . The local cooling device  10  may be inserted into and advanced to reach a target location  50  within the body, such as in a vessel  55 .  
         [0033]     The local cooling device  10  includes an elongate shaft  20  and has a perfusion lumen  30  extending longitudinally therethrough. The perfusion lumen  30  extends from a proximal end  22  to a distal end  24  of the cooling device  10 . An adapter  40  is attached to the proximal end  22  of the cooling device  10 . Fluid  70  may be introduced into the perfusion lumen  30 , pass through the perfusion lumen  30  and exit near the distal end  24  of the cooling device  10 . The fluid  70  treats target location  50 . A wire loop  36  and blood channeler  60  may be deployed from the cooling device  10  (as shown in  FIG. 1 ) to divert blood flowing through the body vessel away from the target location  50 .  
         [0034]     This may be useful in various treatments. For example, a cooled fluid may be passed through the perfusion lumen  30  while the blood is diverted through the blood channeler  60 . This allows the cooled fluid to remain localized for a longer period of time at the target location  50 , enabling a more rapid, effective cooling of the target location  50 , while decreasing the amount of cooled fluid that is required for cooling. In addition, the cooled fluid may be more concentrated at the target location  50  which may result in achieving lower temperatures and more localized cooling.  
         [0035]     Referring again to  FIG. 1 , the cooling device  10  is shown deployed in a body vessel  55 . The cooling device  10  has a proximal end  22 , and an adapter  40  is attached to the proximal end  22  of the cooling device  10 . The adapter  40  includes a fluid entry port  42  allowing the introduction of fluid and a wire access port  44  allowing the manipulation of a wire  34  to assist in deploying the wire loop  36  and blood channeler  60 .  
         [0036]     The cooling device  10  includes a wire  34  that runs from near the proximal end  22  to near the distal end  24  of the cooling device  10 , and may also pass through and exit the adapter  40 . In  FIG. 1 , the wire  34  is shown coming out of the wire access port  44  of the adapter  40 . The wire  34  connects to the wire loop  36  located near the distal end  24  of the cooling device  10 . The wire loop  36  is bonded to the blood channeler  60 . The blood channeler  60  has a proximal end formed by the wire loop  36 , and a distal end  62 . The wire loop  36  controls the diameter size of the proximal end of the blood channeler  60 . When deployed in a body vessel  55 , such as a coronary artery, the wire loop  36  of the cooling device  10  expands to just slightly smaller than the diameter of the body vessel  55  in front of the target location  50 . Thus, the blood channeler  60 , having a generally tubular construction, has a diameter at the proximal or blood entry end just slightly smaller than the internal diameter of the body vessel in which it is deployed. The blood channeler  60  also has a reduced, or necked, area  64 , and an exit port  66 , located at the distal end  62  of the blood channeler  60 . When the wire loop  36  and blood channeler  60  are fully deployed, blood  52  flowing through the body vessel enters the proximal end of the blood channeler  60  formed by the wire loop  36 . This diverts the majority of the blood moving through the body vessel  55  from a target location  50  by passage through the blood channeler  60 . The blood travels through the blood channeler  60 , through the narrowest part, the neck  64  of the blood channeler  60 , and then exits through the exit port  66  at the distal end  62  of the blood channeler  60 .  
         [0037]     Fluid may be introduced by passing fluid through the fluid entry port  42  and into the perfusion lumen  30  at the proximal end  22  of the cooling device  10 . The fluid travels through the perfusion lumen  30 , and exits via the fluid exit port  32  near the distal end  24  of the cooling device  10 . The fluid exit port  32  is located distal of the wire loop  36  and the proximal edge of the blood channeler  60  formed by the wire loop  36 . The fluid exit port  32  and is between the outside of the blood channeler  60  and the walls of the body vessel  55 . When properly deployed, the fluid  70  exits the cooling device  10  near target location  50 . The cooling fluid  70  circulates around the outside of the blood channeler  60 , and cools the target area  50  in the body vessel  55 . The cooling fluid  70  stays at the target location  50  for a period of time due to the lack of flow, as the blood  52  is flowing through the inside of the blood channeler  60 . Near the distal end  62  of the blood channeler  60 , the cooling fluid  70  and the blood  52  mix. Thus, the deployed blood channeler  60  diverts most, if not all, of the blood  52  from the target location  50 , allowing the cooling fluid  70  to treat the target area  50 .  
         [0038]     When undeployed, the wire loop  36  and blood channeler  60  are stored in a device lumen  38  located near the distal end of the shaft  20 . The wire  34  may be advanced or pushed to deploy the wire loop  36  and blood channeler  60  from the device lumen  38  near the distal end  24  of the cooling device  10 . The device lumen  38  has a device exit port  28  at the distal end of the device lumen  34 , where the wire loop  36  and blood channeler  60  may exit the shaft  20 . The device lumen  38  may extend longitundinally from the proximal end  22  to near the distal end  24  of the cooling device  10 . Alternatively, the device lumen  38  may only extend a short distance to near the distal end  24  of the cooling device. The device lumen  38  is large enough to allow storage of the wire loop  36  and blood channeler  60  before deployment, and allow retraction of the wire loop  36  and blood channeler  60  after treatment has completed.  
         [0039]     The local cooling device  10  may be advanced to a target location  50  by inserting the cooling device  10  into the body via a vessel, such as an artery, and then advanced to the target location  50 . Alternatively, the cooling device  10  could be advanced over a guidewire (not shown) which may be used to guide the cooling device  10  to the target location  50 . After the cooling device  10  reaches the target location, the guidewire may be removed from the body vessel and the body. When using a guidewire, the perfusion lumen  30  may be used as a lumen for passage of the guidewire.  
         [0040]      FIG. 2  shows a side perspective of the cooling device  10  of  FIG. 1  in an undeployed state. The wire loop  36  and blood channeler  60  are within the device lumen  38  (all not shown in  FIG. 2 ), and may be deployed via device exit port  28  by operation of the wire  34 .  
         [0041]      FIG. 3  shows a more detailed view of the portion of the cooling device  10  near the distal end  24  of the cooling device  10 . The wire loop  36  and blood channeler  60  are shown in a deployed state. As can be seen, the wire  34  is operably connected to wire loop  36 , and can be used to advance the wire loop  36  and blood channeler  60  from the device lumen  38  and out of the device exit port  28 . The wire  34  may also be used to retract the wire loop  36  and blood channeler  60  back into the device lumen  38  via the device exit port  28 . A distal portion of the lumen thus serves as a storage area for the deployable blood channeler  60 .  
         [0042]      FIG. 4  shows a cross section of the shaft  20 , taken along cut lines  4 - 4  in  FIG. 3 . This cross section shows the perfusion lumen  30  and the device lumen  38 , both formed by the shaft  20 . Wire  34  runs through the device lumen  38 .  
         [0043]     Another embodiment of a local cooling device  110  in accordance with the invention is shown in  FIG. 5 , which is a perspective view of the cooling device  110  near the distal end  124  of the cooling device  110 . The cooling device includes an elongate shaft  120 , and has a proximal end (not shown) and a distal end  124 . A perfusion lumen (not shown) is formed by the shaft  120 , and has a fluid exit port  132  at the distal end  124  of the cooling device.  
         [0044]     A wire (not shown) runs the length of the shaft and is operably connected to a wire loop  136 . The wire loop  136  is bonded to a blood channeler  160 . The wire loop  136  forms the proximal end of the blood channeler  160 . The blood channeler  160  also has narrow neck portion  164 , and a distal end  162 . An exit port  166  is located at the distal end  162  of the blood channeler  160 .  
         [0045]     A filter material  180  is bonded to the outside of the distal end  162  of the blood channeler  160 . The filter material  180  extends outward from the blood channeler  160 , and contacts the walls in the body vessel when deployed. The filter material  180  may be made of filter mesh formed from a polymer or other material. A number of traces  182  are bonded or connected to the wire loop  136  periodically around the circumference of the wire loop  136 . These traces  182  run from the wire loop  136  to a point at which the traces  182  bond or connect to the filter material  180 . Thus, there are a number of places around the circumference of the wire loop  136  of the local cooling device  110  at which the traces  180  are bonded or connected to filter material  180 . The traces  182  may be formed of a material, such as a shape memory material, that assists in maintaining the filter material  180  deployed.  
         [0046]     When deployed, the wire loop  136  will contact the walls of the body vessel  155 , and blood  150  flowing through the body vessel  155  will be diverted through the blood channeler  160 . When fluid  170  is passed through the perfusion lumen (not shown) and out of the fluid exit port  132 , the fluid  170  will treat target location  150 . During treatment, some material may be dislodged from the target location  150 . For example, the cooling may dislodge blood clots, cholesterol pieces, or bits of plaque. The deployed filter material  180  will catch and retain particles or dislodged material larger than the pore size of the filter material  180 , and not allow those particles to proceed further in the bloodstream.  
         [0047]     After treatment, when the wire loop  136  and blood channeler  160  are retracted into the device lumen (not shown) of the local cooling device  110 , the filter material  180  and traces  182  will also be retracted. These components may be retracted into the local cooling device in such a way that the filter material  180  and traces  182  interact to close the filter material  180  as it retracts. Thus, any particles or material captured in the filter material  180  would not be dislodged into the blood stream, but would be kept in the filter material  180  by operation of the traces  182 . Thus, the dislodged material will also be retracted into the device lumen and removed from the body when the local cooling device  110  is removed from the body.  
         [0048]     In another embodiment, the area between the traces may also partly or fully include a filter material. This would enable the use of solid particles, such as small ice particles, to be passed through the perfusion lumen and used for localized cooling. The enclosing filter would retain these ice particles until they are less than a determined size. This would enable more rapid cooling.  
         [0049]     Another embodiment of a local cooling device  110  in accordance with the invention is shown in  FIGS. 6 and 7 .  FIG. 6  is a perspective view of the cooling device  210  near the distal end  224  of the cooling device  210 . The cooling device includes an elongate shaft  220 , and has a proximal end (not shown) and a distal end  224 . A perfusion lumen (not shown) is formed by the shaft  220 , and runs throughout the shaft  220  from the proximal end of the cooling device  210  to near the distal end  224 . The perfusion lumen is connected to a perfusion sheath  231 .  
         [0050]     A wire  234  is operably connected to a wire loop  236 . A blood channeler  260  is bonded to the wire loop  236 . The blood channeler  260  has a proximal end formed by the wire loop  236 , a reduce area  264  located at about the midpoint of the blood channeler  260 , and a distal end  262 . A device exit port  232  is located at the distal end  262  of the blood channeler  260 .  
         [0051]     The cooling device  210  is shown in a deployed state in  FIG. 6 . The perfusion sheath  231  is wrapped in a spiral manner around the outside of the blood channeler  260 . The perfusion sheath  231  has numerous perfusion exit ports  233  located along its length. The perfusion exit ports  233  point outward from the blood channeler  260 . When fluid is perfused through a device in the body, there is a risk of perfusion injury due to the flow of the fluid. The numerous perfusion exit ports  233  in the perfusion sheath  231  reduce the risk of injury, as the fluid is perfused through numerous perfusion exit ports  233 . The sum of the areas of the perfusion exit ports  233  exceeds the area of the device exit port  232 . Preferably, the sum of the areas of the perfusion exit ports  233  will be at least twice the area of the device exit port  232 .  
         [0052]     When undeployed, the wire loop  236 , blood channeler  260 , and perfusion sheath  231  reside within the cooling device  210  near the distal end  224 . When deployed, the wire  234  may be advanced, which advances the wire loop  236 , blood channeler  260 , and perfusion sheath  231  out of the device exit port  232  located at the distal end  224  of the cooling device  210 . After treatment is complete, the wire  234  may be retracted, which in turn, retracts the wire loop  236 , blood channeler  260 , and perfusion sheath  231 .  
         [0053]      FIG. 7  is a cross-sectional view of a portion of the cooling device of  FIG. 6  near the distal end of the cooling device. This view shows a perfusion lumen  230  and a device lumen  238  formed by the shaft  220  of the cooling device  210 . The wire  234  extends through the device lumen  238  and is connected with the wire loop  236 . The perfusion sheath  231  is shown attached to the interior of the shaft  220 , and exits the cooling device  210  via the device exit port  232 , before wrapping around the blood channeler  260 . Fluid is able to flow through the perfusion lumen  230  and into the perfusion sheath  231 . When not deployed, the wire loop  236 , perfusion sheath  231 , and blood channeler  260  are stored in the distal end of the cooling device  210 . The wire loop  236 , perfusion sheath  231 , and blood channeler  260  are deployed by advancing through the device exit port  232 , and undeployed by retracting through the device exit port  232 . A distal portion of the device inside the shaft  220  thus serves as a storage area for the deployable blood channeler  260 .  
         [0054]     One concern with the application of cooling fluids into body vessels is the possibility of damage to the body vessel caused by jetting. As the fluids exit into the body vessel from a delivery device, there is the possibility that the fluid will damage the body vessel due to the flow rate of the cooling fluid. The following embodiments address this potential issue by perfusing from the outside in. The walls of the body vessel are protected by a layer of material of the delivery device.  
         [0055]     An embodiment of a local cooling device  310  in accordance with the invention, shown in  FIG. 8 , includes an elongate shaft  320  having a proximal end (not shown) and a distal end  322 . The shaft  320  has a perfusion lumen (not shown) formed by the shaft  320 . The perfusion lumen extends from an entry port (not shown) near the proximal end of the cooling device  310  to a series of exit ports  326 , near the distal end  322  of the shaft  320 .  
         [0056]     The local cooling device  310  also includes a blood channeler  360 . The blood channeler  360  includes ribs  362  and a material portion  364 . The ribs  362  may be formed from a shape memory material, such as nitinol, or other material. The ribs  362  are connected to the sheath material  364 , for example by bonding.  
         [0057]     When fully deployed, the ribs  362  form a generally spiral configuration, with the ribs  362  and sheath material  364  between the ribs forming a tunnel for blood to flow through. The leading edge of the ribs  362  forms the proximal end of the blood channeler  360 , while the distal end of the blood channeler  360  is formed by the trailing edge of the ribs  362 . The ribs  362  control the diameter size of the blood channeler  360 . The deployed blood channeler  360  deploys to fill the body vessel in which it is deployed, and the blood channeler  360  may touch the vessel walls. The blood channeler  360  may be self-expanding. Alternatively, a wire may be operably connected to the ribs  362 , and advancing the wire may deploy the blood channeler  360 .  
         [0058]     Before deployment, the blood channeler  360  including ribs  362  and sheath material  364  may be partially stored within a device lumen (not shown), and partially wrapped around the outside of the cooling device  310  near the distal end  322  of the cooling device  310 . During deployment, some of the ribs  362  and sheath material  364  is advanced from the device lumen out the device exit port  368 . The blood channeler  360  may deploy by taking advantage of properties of the shape change material. For example, the associated shape change may occur under pressure or temperature change. Alternatively, the blood channeler may deploy by advancing a wire connected to the ribs  362 .  
         [0059]     The cooling device  310  in  FIG. 8  is shown expanded and deployed. The ribs  362  of the cooling device  310  are expanded forming a tunnel. Blood flowing through a body vessel in which the cooling device is deployed enters the proximal end of the blood channeler  360 . At the same time, a cooling fluid  370  is passed through a perfusion lumen and exits at perfusion exit ports  326 . Therefore, as blood travels through the blood channeler  360 , it mixes with the cooling fluid  370 , causing the blood to cool before it exits the distal end of the blood channeler  360 .  
         [0060]     The body vessel  350  is protected as the cooling fluid  370  perfuses through the exit ports  326  towards the middle of the vessel. Thus, the cooling fluid  370  interacts with the blood in the space formed by the blood channeler  360 . In addition, the walls of the vessel are protected by the blood channeler  360 . Therefore, the blood channeler  360  protects the walls of the body vessel, as fluid  370  will strike the blood channeler  360  and not the walls of the body vessel.  
         [0061]     The fluid used with any of the devices of this invention may be blood, saline solution, or another suitable fluid. The fluid may be cooled. The fluid may be oxygenated. The cooled fluid may include particles, such as ice crystals to enhance cooling. The fluid may include drugs, such as an anti-inflammatory, anti-coagulant, or other drug(s) to assist in treating the patient.  
         [0062]     The blood channeler may be formed, for example, of nylon, pebax, POC, PET, ePTFE, urethane, polymer blends, other polymers, or other material. The sheath may be formed of a mono-layer or a multi-layer material. As the inner blood flow and outer cooling fluid flow do not mix until near the distal end of the sheath, there is minimal heat exchange between the fluids over the length of the sheath.  
         [0063]     In order to further decrease heat conductivity across the blood channeler, nano-laminates of dissimilar materials may be applied to the blood channeler. This would act to maintain maximum cooling of the target area, as heat transfer to the flowing blood on the other side of the sheath would be further minimized. It has been found recently that heat cannot be carried efficiently across these material interfaces. Heat is transferred normally by lattice vibrations. When using dissimilar materials, an amount of these lattice vibrations are merely reflected instead of transferred through the material. By making the individual layers only a few nanometers thick, a nanolaminate material with a thermal conductivity three times less than a conventional insulator has been produced. The deposition of single molecule layers of dissimilar materials on top of a base polymeric sheath may be achieved using a polyelectrolyte method.  
         [0064]     Another embodiment of a local cooling device  410  in accordance with the invention is shown in  FIGS. 9 and 10 .  FIG. 9  is a perspective view of the area near the distal end of the cooling device  410 .  FIG. 10  is a cross section of a portion of the cooling device  410  in the area of the expandable sheath  460 , taken along cut lines  10 - 10  in  FIG. 9 .  
         [0065]     The cooling device  410  includes an elongate shaft  420  having a proximal end (not shown) and a distal end  422 . A perfusion lumen  430  is formed by the shaft  420  and extends longitudinally through the shaft  420  to near the distal end  424 . The perfusion lumen  430  extends from an entry port (not shown) to an expandable sheath  460  located near the distal end  424  of the cooling device  410 .  
         [0066]     The cooling device  410  is shown expanded and deployed in  FIG. 9 . Before deployment, the expandable sheath  460  may be wrapped and folded around the shaft  420  in the area near the distal end  424  of the cooling device  410 .  
         [0067]     The expandable sheath  460  may be deployed by injecting a fluid  470  into the perfusion lumen  430  and passing the fluid  470  through the perfusion lumen  430  into the interior of the expandable sheath  460 . The fluid  470  may enter the expandable sheath  460  via perfusion exit ports  472  that lead from the perfusion lumen  430  into the interior of the expandable sheath  460 . The expandable sheath  460  expands and deploys as fluid is passed into the interior of the expandable sheath  460 . The expandable sheath  460  expands to the diameter of a body vessel  450  in which it is located. The expandable sheath is placed just prior to a target location  480  in the body. The expanded sheath has a proximal end  462  and a distal end  464 . As blood  452  travels along the body vessel  450 , it enters the proximal end  462  of the expandable sheath  460 .  
         [0068]     As fluid  470  is passed through the perfusion lumen  430 , and expanding the expandable sheath  460 , some of the fluid  470  also passes through fluid exit ports  426 . Fluid exit ports  426  are located on the interior surface of the expandable sheath  460 , and also the interior surface of the shaft  420  located within tunnel formed by the expandable sheath  460 . These exit ports  426  may be located in perfusion strips forming parts of the sheath, or may be exit ports located as part of the inner surface of the expandable sheath  460 . There may be one or more exit ports  426 .  
         [0069]     Exit port  426  are located along the shaft  420 , and also exit ports  426  along the inner edge of the balloon directly across from the shaft  420 , and exit ports  426  on the inner wall on each side halfway between the other described sets of exit ports  426 . This is more clearly shown in  FIG. 10 . Fluid  470  passes out of the perfusion lumen  430  and into the expandable sheath  460 . Fluid  470  also exits through fluid exit ports  426  located at 0°, 90°, 180°, and 270° around the inside of the expandable balloon  460  in this embodiment as shown in  FIG. 10 .  
         [0070]     As the fluid  470  exits towards the interior of the expandable sheath  460 , the walls of the body vessel  450  are protected from jetting damage. The fluid  470  perfuses through the exit ports  426  towards the middle of the vessel, rather than from the middle towards the walls of the body vessel  450 . Thus, the fluid  470  interacts with the blood  452  in the space formed by the expandable sheath  460 , and would strike the inner wall of the sheath  460  and not the walls of the body vessel  450 . As blood  452  passes through the proximal end  442  of the expandable sheath  460 , and through the expandable sheath  460 , fluid  470  mixes with the blood  452 . When a cooled fluid is used, this mixing causes the blood to cool before it exits the distal end  444  of the expandable sheath  460 .  
         [0071]     The fluid exit ports  426  may be constructed to only allow passage of fluid at a certain pressure or higher. This design enables the expandable sheath  460  to be fully expanded and remain expanded, while fluid  470  is being perfused out of the fluid exit ports  426 . The fluid exit ports  426  may be designed to only allow one direction of fluid flow. Thus, only fluid flowing form the cooling device  410  into the body vessel would be allowed. In such a design, blood  452  could not enter or flow into the cooling device  410 . The uni-directional fluid exit ports would also allow the expandable sheath  460  to be retracted after treatment is completed. Instead of perfusing fluid, a slight vacuum could be pulle don&#39;t eh perfusion lumen  430 . This would evacuate all the fluid from the expandable sheath  460 , and bring the sheath down to where it is closely wrapped on the shaft  420  near the distal end  424  of the cooling device  410 . This would enable the cooling device  410  to be removed form the patient following treatment.  
         [0072]     The expandable sheath may be formed, for example, of nylon, pebax, POC, PET, ePTFE, urethane, polymer blends, other polymers, or other material. The sheath may be formed of a mono-layer or a multi-layer material.  
         [0073]      FIG. 11  shows a system including a local cooling device  810  (only a portion of which is shown) and external equipment attached to the local cooling device  810 . In this example, the proximal end  822  of the shaft  820  of the local cooling device  810  is attached to an adapter  840 . The adapter  840  includes a fluid access port  842  and a wire access port  844 . A wire  834  is shown coming out of the wire access port  844 .  
         [0074]     A control system  800  is shown in box diagram, and includes a controller  802 , a patient monitor  804 , a fluid reservoir  806 , a fluid pump  808 , and a heat exchanger  810 . The controller  802  receives information from the patient monitor  804  and uses that information to control the amount and temperature of the fluid delivers to the local cooling device  820  by controlling the operation of the fluid pump  808  and the heat exchanger  810 .  
         [0075]     Fluid access port  842  on the adapter  840  provides access to a perfusion lumen (not shown) that extends longitudinally through the shaft  820  of the local cooling device  810  to near the distal end (not shown) of the cooling device  810 . The fluid pump  808  is connected to the perfusion lumen via port  842 . The controller  802  controls the operation of the fluid pump  808 , and the amount and rate of cooled fluid provided to local cooling device  820 . The fluid provided to the local cooling device  820  may be blood, saline solution, or another suitable fluid. The fluid may be cooled. The fluid may include pharmaceutical drugs or other materials.  
         [0076]     The port  844  provides access to a device lumen that extends longitudinally through the shaft  820  of the local cooling device  810  to near the distal end of the cooling device  810 . A wire  834  runs from outside the body, via port  844 , and in some embodiments, may be manipulated to deploy and retract the deployable portion of the local cooling device  810 . Typically, the wire  834  may be advanced, retracted, and rotated to assist in operating the local cooling device most effectively and efficiently.  
         [0077]     In other implementations, additional external devices may be added to the control system  800 , or alternatively, some of the devices may be omitted.  
         [0078]     The local cooling device may be used to cool tissue regions in all areas of the body. For example, the local cooling device may be used near the heart or aorta, near the brain, kidneys, and in the legs, torso, or arms.  
         [0079]     A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.