Patent Description:
In modern medicine there are numerous clinical situations in which it is desirable to control or modify body temperature of a patient. For example, hypothermia can be induced in humans and some animals for the purpose of protecting various organs and tissues against the effects of ischemic, anoxic or toxic insult. For example. hypothermia can have neuroprotective and/or cardioprotective effects in patients who suffer an ischemic event such as a myocardial infraction or acute coronary syndrome, post-anoxic coma following cardiopulmonary resuscitation, traumatic brain injury. stroke, subarachnoid hemorrhage, fever or neurological injury. Also, studies have shown that hypothermia can ameliorate nephrotoxic effects of radiographic contrast media (e.g., radiocontrast nephropathy) in patients who have pre-existing renal impairment.

<CIT>) relates to catheters adapted to exchange heat with a body fluid flowing through a body conduit employ helical elongate lumens for heat transfer with the body fluid. The helical elongate lumen of a catheter forms multiple turns extending longitudinally of a portion of the catheter with the turns each being bonded to the catheter along a fraction of the length of the turn. <CIT> relates to closed loop heat exchange catheters having bi-directional flow heat exchange regions and their methods of manufacture and use. The heat exchange region may be formed of expandable or non-expandable tubular conduit(s) that are configured in a series of loops or coiled configuration defining a supply flow path and a return flow path through which heat exchange medium is circulated. The individual loops of convolutions of the coiled configuration may be the same or different size. In some embodiments, the tubular conduit(s) may be passed through generally transverse bore holes formed in a catheter shaft so that the loops or convolutions of protrude from the catheter shaft. <CIT> relates to a heat exchange catheter has a catheter body with an inflow lumen, an outflow lumen, and an infusion lumen. A first heat exchange balloon helically wraps around at least a portion of the catheter body in fluid communication with the inflow lumen. A second heat exchange balloon helically wraps around at least a portion of the catheter body in fluid communication with the outflow lumen. The first and second balloons form a gap there between to facilitate infusion of fluid into the blood stream of the patient via an infusion port formed within the gap. <CIT> relates to a catheter with multiple heating/cooling fibers employing fiber spreading features.

One method for inducing hypothermia--or otherwise modifying or controlling a patient's body temperature-involves insertion of an endovascular heat exchange catheter into the patient's vasculature and circulation of a heat exchange fluid, such as warmed or cooled saline solution, through a heat exchanger located on the catheter. This results in exchange of heat between the circulating heat exchange fluid and blood that is coursing through the patient's vasculature. Because the blood circulates throughout the patient's entire body, this technique can be effective to change the patient's core body temperature to a desired target temperature and to thereafter maintain the target core body temperature for a period of time.

In some clinical situations, it is desirable to induce hypothermia as rapidly as possible. Once such example is in the treatment of acute myocardial infarction. Patients who are diagnosed with acute myocardial infarction are often treated with a coronary intervention or surgery (e.g., angioplasty or coronary artery bypass surgery) to reperfuse the ischemic myocardium. In at least one study, it was observed that patients with anterior wall infarctions whose core body temperature had been lowered to at least <NUM> prior to reperfusion by angioplasty had significantly smaller median infarct size than other patients with anterior wall infarctions whose core body temperature was greater than <NUM> at the time of reperfusion. This observation is not explained by other factors such as time-to-presentation, lesion location or quantity of antegrade coronary flow (TIMI Flow) prior to the angioplasty. This would suggest that, at least in acute myocardial infarction cases, it is desirable to lower the patient's body temperature to at least <NUM> as rapidly as practical so that reperfusion may also be accomplished as rapidly as practical after such hypothermia has been induced.

The claimed invention is defined by appended claim <NUM>. Preferred embodiments are disclosed in the claims. Also described herein are heat exchange catheter devices, systems and example methods which are useable for efficient endovascular heat exchange.

In many cases, the time required to raise or lower a patient's body temperature using an endovascular heat exchange catheter is dependent to at least some degree on the heat heat-exchanging efficiency of the heat exchange catheter. The present disclosure describes improved heat exchange catheters, systems and example methods which provide high-efficiency heat exchange and the ability to rapidly raise or lower a patient's body temperature.

In accordance with one embodiment, there is provided a catheter device which comprises: a catheter body having a distal end, a first lumen and a second lumen; a spine or other elongate member which extends distally from the catheter body, such spine or other elongate member having a plurality of spaced-apart heat exchange member-receiving features therein or thereon. At least one heat exchange member (e.g., one or more heat exchange tubes) is disposed on the spine or other elongate member and connected to the first and second lumens such that fluid may circulate in a distal direction through the first lumen, then through said at least one heat exchange member, then in a proximal direction through the second lumen.

In accordance with another embodiment there is provided a catheter device which comprises: a catheter body having a distal end, a first lumen and a second lumen; a spine or other elongate member which differs from the catheter body and extends distally from the catheter body and at least one heat exchange member (e.g., one or more heat exchange tubes) disposed on the spine or elongate member and connected to said ·first and second lumens of the catheter body such that fluid may circulate in a distal direction through the first lumen, then through said at least one heat exchange member and then in a proximal direction through the second lumen.

In accordance with yet another embodiment, there is provided a catheter device which comprises: a catheter body having a distal end, a first lumen and a second lumen; an elongate member attached to the catheter body and extending beyond the distal end of the catheter body; at least one tube disposed on said elongate member and connected to said first and second lumens such that fluid may circulate in a distal direction through the first lumen, then through said at least one tube and then in a proximal direction through the second lumen; and an elongate luminal member attached to the catheter body and extending substantially parallel to the elongate member, said elongate luminal member having a through lumen extending therethrough; wherein the elongate member comprises tube-receiving features which correspond to the size and shape of elongate member-contacting locations on said at least one tube, the elongate member - contacting locations on said at least one tube are positioned in the tube-receiving features of the elongate member, and the elongate luminal member extends along the elongate member so as to hold the elongate member-contacting locations of said at least one tube in the tube-receiving locations of the elongate member.

In accordance with yet another embodiment, there is provided a method of manufacturing a catheter comprising the steps of: forming or obtaining a proximal catheter body having a distal end and at least first and second lumens extending therethrough; forming or obtaining a spine or other elongate member; disposing at least one tube on the spine or other elongate member; attaching the spine or other elongate member to the proximal catheter body such that the spine or other elongate member extends beyond the distal end of the catheter body; connecting said at least one tube to at least the first and second lumens such that fluid will flow in a distal direction through the first lumen, then through said at least one tube, and then in a proximal direction through the second lumen.

In accordance with still another embodiment, there is provided a method for imparting a desired curved or looped shape to a tube or other workpiece which has a lumen or passageway extending therethrough. This method generally comprises the steps of i) advancing the tube or other workpiece over or in the forming member while the forming member is in an initial (e.g., substantially straight) configuration; ii) causing the forming member to transition to the desired curved or looped shape, thereby imparting that curved or looped shape to the tube or other workpiece positioned on the forming member; and removing the forming member from the tube or other workpiece while maintaining the tube or other workpiece in the desired curved or looped configuration. This method may be used to impart the looped configuration to heat exchange tubes or other luminal heat exchange members used on various catheter described herein.

In accordance with other embodiments! there are provided systems which comprise any catheter described herein in combination with fluid pumping apparatus operative to cause fluid to circulate in a distal direction through at least one heat exchange member (or at least one segment of a unitary heat exchange member) and then return in a proximal direction through a second heat exchange member (or second segment of a unitary heat exchange member). Such systems may include additional components such as fluid heating or cooling and control apparatus. Examples of endovascular heat exchange systems having pumping, heating/cooling and control apparatus useable in conjunction with the present catheters include but are not limited to those described in <CIT>); <CIT>) and <CIT>) as well as <CIT>). Additionally <CIT>) and <CIT> (<CIT>) and <CIT> (<CIT>) are referred to.

Whereas the claims define a catheter device, other examples in the present disclosure provide methods for modifying or controlling body temperature of a human or animal subject wherein the method comprises the steps of: (i) inserting any embodiment of a catheter described herein into vasculature of the subject such and (ii) circulating heated or cooled heat exchange fluid through the catheter to thereby exchange heat with the subject's flowing blood resulting in modification or control of the subject's body temperature, to treat various conditions, e.g., to treat acute myocardial infarction.

In accordance with yet another embodiment, there is provided a recirculating distal tip for a circulating fluid catheter in which a fluid circulates in a distal direction through a first member on the catheter and then returns in the proximal direction through a second member on the catheter. The recirculating distal tip member has a hollow inner cavity and is connected to the first and second member such that fluid which flows in the distal direction through the first member will pass through the hollow inner cavity of the recirculation tip member and then into the second member such that it will then flow in the proximal direction through the second member. In some embodiments, the catheter may have a through lumen tube which extends through the hollow inner cavity of the recirculating distal tip to an opening in the distal end of the recirculating tip member. The through lumen tube is sealed to the recirculating distal tip member such that fluid which circulates through the hollow inner cavity of the recirculating tip member will not leak into or enter the lumen of the through lumen tube and any fluid that is infused through the trough lumen tube will not leak into or enter the hollow inner cavity of the recirculating tip member.

This disclosure includes a catheter device comprising: a catheter body having a distal end, a first lumen and a second lumen; an elongate member which extends distally from the catheter body, said elongate member having a plurality of spaced-apart heat exchange member-receiving features therein or thereon; at least one heat exchange member disposed on the elongate member and connected to said first and second lumens such that fluid may circulate in a distal direction through the first lumen, then through said at least one heat exchange member, then in a proximal direction through the second lumen.

The at least one heat exchange member may comprise at least one tube configured in a series of loops. The at least one heat exchange member may comprise a continuous tube having a first segment which runs from the catheter body to a distal location on the elongate member and a second segment that returns from the distal location on the elongate member to the catheter body. The loops may be helical. Helical loops of a first size may be formed in a first tube or first tube segment. Helical loops of a second size may be formed in a second tube or second tube segment. The loops may be aligned in a row. Loops of the first size may alternate with the loops of the second size.

The at least one heat exchange member may be selected from: a single heat exchange member having a first segment through which heat exchange fluid circulates in a distal direction and a second segment through which heat exchange fluid circulates in a proximal direction; or a plurality of heat exchange members including at least a first heat exchange member through which heat exchange fluid circulates in a distal direction and a second heat exchange member which is connected to the first heat exchange member such that fluid which has flowed in the distal direction through the first heat exchange member then flows in the proximal direction through the second heat exchange member.

Helical loops may be formed in said at least one heat exchange member. Helical loops of a first size may be formed in the first segment or first heat exchange member. Helical loops of a second size may be formed in the second segment or second heat exchange member. The first segment or first heat exchange member and the second segment or second heat exchange member may be disposed on the elongate member such that the loops of the loops are aligned in a row. The loops of the first size may alternate with the loops of the second size.

The at least one heat exchange member may comprise a first heat exchange member through which heat exchange fluid circulates in a distal direction, a second heat exchange member through which heat exchange fluid circulates in a proximal direction and a fluidic connection between the first and second heat exchange members, and, the fluidic connection may comprise a recirculating distal tip on a distal end of the elongate member, wherein the first and second heat exchange members are connected to the recirculating distal tip such that fluid may flow from the first lumen of the catheter body, in a distal direction through the first heat exchange member, through the recirculating distal tip, in a proximal direction through the second heat exchange member and then into the second lumen of the catheter body.

The catheter device may further comprise: a third lumen extending through the catheter body; and an elongate luminal member attached to the catheter body and extending substantially parallel to the elongate member, said elongate luminal member which has a lumen extending longitudinally therethrough.

Portions of said at least one heat exchange member may be captured between the elongate member and the elongate luminal member. The catheter device may further comprise adhesive which adheres said at least one heat exchange member to at least one of the elongate member and the elongate luminal member. At least one heat exchange member may comprise at least one heat exchange tube. At least one heat exchange tube may be collapsed when empty and expanded when filled with fluid. At least one heat exchange tube may be formed of a non-compliant polymer material. The elongate member has receiving features formed therein or thereon, said receiving features may correspond to the size and shape of elongate member-contacting locations on said at least one heat exchange member. The elongate member-contacting locations on said at least one heat exchange member may be positioned in the receiving features. The receiving features may be selected from: clips, projections, prongs, depressions, indentations, locator markings, notches, grooves, troughs, apertures, bores, through holes and open areas formed in the elongate member within which said locations on said at least one heat exchange member is fully or partially positioned. At least one heat exchange member may be adhered to the elongate member. Elongate member-contacting locations may be adhered to the receiving features. The elongate luminal member may comprise a tube. The elongate member comprises an elongate member having receiving features formed thereon or therein. The receiving features may correspond to the size and shape of elongate member-contacting locations on said at least one heat exchange member. The elongate member-contacting locations on said at least one heat exchange member may be positioned in the receiving features formed on or in the elongate member; and the elongate luminal member may be mounted on the elongate member so as to retain said at least one heat exchange member within the receiving features. A series of said receiving features may be formed along the elongate member; said at least one heat exchange member may be formed in a series of loops, elongate member-contacting locations on at least some of the loops may be positioned in the receiving features; and, the elongate luminal member may be mounted on the elongate member so as to retain said loops within the receiving features. At least one heat exchange member may be also adhered to the elongate member. The elongate member-contacting locations may be adhered to the receiving features. The loops may be helical. The helical loops may comprise helical loops of differing diameter. The helical loops may be arranged to alternate between loops of a first diameter and loops of a second diameter. At least one heat exchange member may comprise at least one tube formed of polymer material, having a diameter of <NUM>" (<NUM>) and a wall thickness of <NUM>" (<NUM>). Said at least one tube, when empty, may be collapsible to size that will pass through a <NUM> French (<NUM>) or greater introducer. When filled with fluid, said at least one tube may assume an expanded configuration having a diameter in the range of from approximately <NUM> inch (<NUM>) to approximately <NUM> inch (<NUM>). At least one heat exchange member may have between <NUM> and <NUM> helical loops. At least one heat exchange member may have <NUM> helical loops. The size and number of helical loops may be such that the catheter is capable of delivering at least about <NUM> watts of cooling power when saline solution operated within a rigid <NUM> ID tube through which water at a temperature of <NUM> degrees C is pumped at a rate of <NUM> liters per minute. The catheter body may have a plurality of inflow lumens and a single outflow lumen and said at least one tube may comprise: a plurality of distal circulation tubes or tube segments, each of which is connected to an inflow lumen of the catheter body and a single proximal circulation tube or tube segment which is connected to the outflow lumen of the catheter body; wherein fluid may be circulated in the distal direction through the plurality of inflow lumens, then in the distal direction through the plurality of distal circulations tubes or tube segments, then in the proximal direction through the single proximal circulation tube or tube segment and then in the proximal direction through the single outflow lumen of the catheter body. The catheter body may have a single inflow lumen and a plurality of outflow lumens and said at least one tube may comprise: a single distal circulation tube or tube segment which is connected to the inflow lumen of the catheter body and a plurality of proximal circulation tubes or tube segments, each of which is connected to an outflow lumen of the catheter body; wherein fluid may be circulated in the distal direction through the single inflow lumen, then in the distal direction through the single distal circulation tube or tube segment, then in the proximal direction through the plurality of proximal circulation tubes or tube segments and then in the proximal direction through the plurality of outflow lumens of the catheter body.

According to another aspect, there is provided a system comprising a catheter device as described above in combination with at least one device selected from a guidewire or a temperature sensor sized to be advanced through the lumen of the luminal member.

According to another aspect, disclosed herein is a system comprising a catheter device as described above in combination with fluid pumping apparatus operative to cause fluid to circulate in a distal direction through the first lumen, then through said at least one tube and then in a proximal direction through the second lumen.

According to another aspect, disclosed herein is a system comprising a catheter device as described above in combination with fluid pumping apparatus operative to cause fluid to circulate fluid in a distal direction through the first lumen, then in the distal direction through the first tube segment, then in a proximal direction through the second tube segment and then in the proximal direction through the second lumen.

According to another aspect, disclosed herein is an endovascular temperature management system comprising a catheter as described above in combination with fluid heating or cooling and pumping apparatus operative to cause heated or cooled heat exchange fluid to circulate in a distal direction through the first lumen, then through said at least one tube and then in a proximal direction through the second lumen.

According to another example, disclosed herein is a method for using a catheter device or system as described above to modify or control body temperature of a human or animal subject, said method comprising the steps of: inserting the catheter device into vasculature of the subject such that said at least one tube is within the vasculature in contact with the subject's flowing blood; and circulating heated or cooled heat exchange fluid in a distal direction through the first lumen of the catheter body, then through said at least one tube and then in a proximal direction through the second lumen of the catheter body to thereby exchange heat with the subject's flowing blood resulting in modification or control of the subject t's body temperature.

According to another aspect, disclosed herein is a method of manufacturing a catheter comprising the steps of: forming or obtaining a proximal catheter body having a distal end and at least first and second lumens extending therethrough; forming or obtaining an elongate member; disposing at least one tube on the elongate member; attaching the elongate member to the proximal catheter body such that the elongate member extends beyond the distal end of the catheter body; connecting said at least one tube to at least the first and second lumens such that fluid will flow in a distal direction through the first lumen, then through said at least one tube, and then in a proximal direction through the second lumen. The method may further comprise causing said at least one tube to have a looped configuration. The at least one tube may be caused to have a looped configuration by: i) advancing said at least one tube onto a substantially straight forming member; ii) cusing the substantially straight forming member to assume a curved configuration thereby imparting the looped configuration to said at least one tube; and iii) removing the forming member from the tube while maintaining said looped configuration. The forming member may be preformed to the curved configuration, elastically or super-elastically deformed to and constrained in the substantially straight configuration during advancement of said at least one tube onto the forming member and, thereafter, relieved of said constraint thereby allowing the forming member to elastically or superelastically transition to its pre-formed curved configuration, thereby imparting the looped configuration to said at least one tube. The forming member may comprise a shape memory material and may be transitionable from a first state in which it has the substantially straight configuration to a second state in which it has the curved configuration wherein the forming member may be maintained in the first state during advancement of said at least one tube onto the forming member and, thereafter, transitioned to the second state, thereby imparting the looped configuration to said at least one tube. The shape memory transition from the first state to the second state may be caused to occur by changing the temperature of the forming member. The forming member may be formed of nickel-titanium alloy. The nickel-titanium alloy may comprise <NUM> wt. % nickel / balance titanium. The forming member may be in the first state when at a temperature between <NUM>° and <NUM>° and in the second state when at a temperature above <NUM>° or below <NUM>°. The forming member may be maintained at a temperature between <NUM>° and <NUM>° during advancement of said at least one tube onto the forming member and thereafter cooled to a temperature below <NUM>° or warmed to a temperature above <NUM>° to cause the forming member to transition to the second state. The step of forming or obtaining an elongate member may comprise obtaining a workpiece which comprises an elongate solid member and forming a series of tube-receiving locations in that elongate solid member. The tube-receiving locations may comprise: clips, clamps, cradles, projections, prongs, depressions, indentations, notches, grooves, troughs, apertures, bores, through holes and open areas formed in or on the elongate member, within which one or more tube(s) may be fully or partially positioned. The step of disposing at least one tube on the elongate member may comprise adhering said at least one tube to the elongate member. The step of disposing at least one tube on the elongate member may comprise adhering spine or member-contacting locations on said at least one tube to tube-receiving locations on the elongate member. The step of disposing at least one tube on the spine or elongate member may comprise thermally welding elongate member-contacting locations on said at least one tube to tube-receiving locations on the elongate member.

The method of manufacturing may further comprise the step of disposing an elongate luminal member longitudinally along said elongate member. The catheter body may have a third lumen and the method may further comprise the step of connecting a proximal end of the elongate luminal member to the third lumen of the catheter body. The elongate member may comprise a spine member having tube-receiving locations formed therein; and the step of disposing at least one tube on the spine member may comprise placing spine-contacting locations on said at least one tube in the tube-receiving locations on the spine member; and the step of disposing an elongate luminal member longitudinally along said spine may comprise attaching an elongate luminal member to the spine such that the elongate luminal member holds the spine-contacting locations of said at least one tube in the tube-receiving locations of the spine member. In addition to being held in the tube-receiving locations by the elongate luminal member, the spine contacting locations on said at least one tube may be also adhered or thermally welded to the tube-receiving locations. The elongate luminal member may comprise a tube which is attached to the spine member so that it extends along one side of the spine member and frictionally engages spine-contacting locations of said at least one tube so as to deter them from moving out of the tube-receiving locations on the spine member. The at least one tube member may comprise a distal circulation tube or tube member which has a proximal end and a distal end and a proximal circulation tube member which has a proximal end and a distal end; and the method may further comprise attaching or forming a recirculating distal tip member to the distal end of the elongate member; and the step of connecting said at least one tube to at least the first and second lumens may comprise: connecting the proximal end of the distal circulation tube to a first lumen of the catheter body, connecting the proximal end of the distal circulation tube to the recirculating distal tip member, connecting the distal end of the proximal circulation tube to the recirculating distal tip member and connecting the proximal end of the proximal circulation tube to a second lumen of the catheter body such that fluid may circulate in the distal direction through the first lumen of the catheter body, then in the distal direction through the distal circulation tube, then through the recirculating distal tip member, then in the proximal direction through the proximal circulation tube and then in a proximal direction through the second lumen of the catheter body.

According to another aspect, disclosed herein is a catheter device comprising: an elongate catheter having a proximal end and a distal end; at least one heat exchanger disposed on a distal portion of the elongate catheter proximate its distal end; and a fluid recirculating tip member on the distal end of the elongate catheter, said fluid recirculating tip member comprising an enclosure having a recirculation cavity therewithin; wherein the heat exchanger comprises at least one distal flow heat exchange element through which a heat exchange fluid flows in the distal direction and at least one proximal flow heat exchange element through which heat exchange fluid flows in the proximal direction; and wherein said least one distal flow heat exchange element and said least one proximal flow heat exchange element are in fluid communication with the recirculation cavity so that fluid that flows in the distal direction through said least one distal flow heat exchange element will enter the recirculation cavity and will subsequently flow from the recirculation cavity in the proximal direction through said at least one proximal flow heat exchange element. The fluid recirculating tip member may have a tapered, conical, frustoconical, blunt conical, ogive or bullet shape. The catheter device may further comprise a through lumen that extends longitudinally through at least a portion of the elongate catheter and though the fluid recirculating tip member, said through lumen being fluidly isolated from the recirculation cavity. The through lumen may comprise, in part, the lumen of a tube which extends longitudinally through the recirculation cavity of the recirculating tip member. A distal end of the tube may terminate at a distal aperture formed in the recirculating tip member.

According to another aspect, disclosed herein is a heat exchange catheter comprising an elongate flexible catheter body, a heat exchange region through which heat exchange fluid circulates and a recirculating distal tip member through which said heat exchange fluid also circulates. The heat exchange catheter may further comprise a through lumen which extends through at least a portion of the catheter body and through the recirculating distal tip member, said through lumen being fluidly isolated from heat exchange fluid circulating through the recirculating distal tip member such that heat exchange fluid does not enter the through lumen. The recirculating distal tip member may be formed of material that differs in hardness from the adjacent catheter body. The recirculating distal tip member may differ in radio-opacity from the adjacent catheter body. The recirculating distal tip member may comprise an enclosure having a recirculation cavity therein and the through lumen may comprise, in part, the lumen of a tube that extends through the recirculation cavity and terminates distally at a distal aperture formed in the recirculating tip member. The fluid recirculating tip member may have a tapered, conical, frustoconical, blunt conical, ogive or bullet shape with the distal aperture formed therein.

According to another example, disclosed herein is a method for warming or cooling the body of a human or animal subject comprising the steps of: positioning a heat exchange catheter in the subject's vasculature, wherein the heat exchange catheter comprises (i) a catheter body having a distal end, a first lumen and a second lumen, (ii) a elongate member attached to the catheter body and extending beyond the distal end of the catheter body and (iii) at least one tube disposed on the elongate member and connected to said first and second lumens; and circulating warmed or cooled heat exchange fluid in a distal direction through the first lumen, then through said at least one tube and then in a proximal direction through the second lumen, thereby warming or cooling the body of the subject. The at least one tube may be configured in a series of loops. The at least one tube may comprise a single tube having a first segment that runs from the catheter body to a distal location on the elongate member and a second segment that returns from the distal location on the elongate member to the catheter body. Helical loops may be formed in said at least one tube. Helical loops of a first size may be formed in the first tube segment and helical loops of a second size may be formed in the second tube segment. The first and second tube segments may be disposed on the elongate member such that the helical loops are aligned in a row. The loops of the first size may alternate with the loops of the second size. The method may be applied where the human or animal is suffering from an acute myocardial infarction and the warming or cooling of the body results in treatment of the acute myocardial infarction.

According to another aspect, disclosed herein is a heat exchange catheter system comprising: a heat exchange catheter which comprises (i) a catheter body having a distal end, (ii) a elongate member attached to the catheter body and extending beyond its distal end, and (iii) at least one helically coiled tube disposed on the elongate member and connected to delivery and return lumen in the catheter body; and fluid cooling apparatus connected to the delivery and return lumens of the catheter body and operative to circulate a cooled thermal exchange fluid through said at least one helically coiled tube; wherein the fluid cooling apparatus and said at least one helically coiled tube are sized, configured and constructed to render the system capable of delivering at least about <NUM> watts of cooling power when operated within a rigid <NUM> ID tube through which water at a temperature of <NUM> degrees C is pumped at a rate of <NUM> liters per minute.

According to another aspect, disclosed herein is a catheter device comprising: a catheter body having a distal end, a first lumen and a second lumen; a spine which differs from the catheter body and extends distally from the catheter body; at least one heat exchange member disposed on the spine and connected to said first and second lumens of the catheter body such that fluid may circulate in a distal direction through the first lumen, then through said at least one heat exchange member and then in a proximal direction through the second lumen. The spine may have different flexural properties than the catheter body. The spine may be more rigid than the catheter body. The spine may have a plurality of spaced-apart tube-receiving features therein or thereon and wherein said at least one tube may be received within the tube-receiving features. The spine may be formed of substantially solid material.

According to another aspect, disclosed herein is a catheter device comprising: a catheter body having a distal end, a first lumen and a second lumen; an elongate member attached to the catheter body and extending beyond the distal end of the catheter body; at least one tube disposed on said elongate member and connected to said first and second lumens such that fluid may circulate in a distal direction through the first lumen, then through said at least one tube and then in a proximal direction through the second lumen; and an elongate luminal member attached to the catheter body and extending substantially parallel to the elongate member, said elongate luminal member having a through lumen extending therethrough, wherein the elongate member comprises tube-receiving features which correspond to the size and shape of spine or mamber-contacting locations on said at least one tube, the spine or member-contacting locations on said at least one tube are positioned in the tube-receiving features of the spine or elongate member, and the elongate luminal member extends along the spine so as to hold the spine or member-contacting locations of said at least one tube in the tube-receiving locations of the spine or elongate member.

Still further aspects and details of the present invention will be understood upon reading of the detailed description and examples set forth herebelow.

The following detailed description and examples are provided for the purpose of non-exhaustively describing some, but not necessarily all, examples or embodiments of the invention.

The following detailed description and the accompanying drawings to which it refers are intended to describe some, but not necessarily all, examples or embodiments of the invention. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The contents of this detailed description and the accompanying drawings do not limit the scope of the invention in any way.

Applicant is filing on even date herewith a patent application entitled High Efficiency Heat Exchange Catheters for Control of Patient Body Temperature.

<FIG> shows an endovascular temperature management system <NUM> which generally includes a control console 10a and an endovascular heat exchange catheter 10b. <FIG> show further details of the endovascular heat exchange catheter 10b.

The console 10a comprises a housing <NUM> within which, or on which, there are positioned heating/cooling apparatus <NUM> for alternately heating and cooling a heat exchange fluid, a pump <NUM> for pumping the heat exchange fluid and a programmable controller <NUM>. A user interface <NUM>, such as a liquid crystal display (LCD), is in communication with the controller <NUM>. The user interface displays system information and also receives user input as well as sensor data, as described more fully herein.

A source of heat exchange fluid <NUM>, such as a bag or container of sterile <NUM> % NaCl solution, is connected by tubing to the heater/cooler <NUM>. Also connected to the heater/cooler <NUM> are proximal ends of a heat exchange fluid outflow line OL and a heat exchange fluid inflow line IL.

A body temperature sensor TS is connected by way of a temperature lead TL, or alternatively by wireless connectivity, to the controller <NUM>.

The endovascular heat exchange catheter 10b generally comprises a proximal catheter body <NUM> and an endovascular heat exchange assembly <NUM>. In this particular embodiment, the proximal catheter body <NUM> has three lumens, an inflow lumen, an outflow lumen and an optional through lumen. The heat exchange assembly <NUM> comprises a spine or elongate member <NUM> and at least one heat exchange member <NUM> disposed on the spine or elongate member <NUM>. The heat exchange assembly <NUM> is attached to and extends distally from the proximal catheter body <NUM>, as shown. An introducer sheath may be used to introduce the catheter into a patient's body. Alternatively, the catheter may be introduced without using an introducer sheath.

The term "elongate member," may mean, in at least some embodiments, a member, e.g., a spine or similar structure, which extends from a catheter body and upon which at least one heat exchange member is disposed. In at least some embodiments, the elongate member <NUM> is distinguishable from the catheter body <NUM> on the basis of one or more differences in structure or physical property. For example, the elongate member <NUM> may be more or less rigid than the catheter body. The elongate member <NUM> has receiving features <NUM> configured to receive the heat exchange member(s) <NUM>. Such receiving features <NUM> may comprise transverse notches formed in one side of the elongate member as seen in <FIG> and <FIG> or, alternatively, may comprise any other clips, clamps, cradles, projections, prongs, depressions, indentations, locator marks, notches, grooves, troughs, apertures, bores, through-holes or open areas in or on which the heat exchange member(s) <NUM> is/are fully or partially positioned. In some embodiments, the elongate member <NUM> may be formed of solid or substantially solid material and/or may be devoid of any lumen(s) that extend longitudinally through the elongate member <NUM>. In some embodiments, the elongate member <NUM> may have one or more lumens extending longitudinally through the elongate member <NUM>. Alternatively, in certain embodiments, the elongate member may comprise a continuation, e.g., a distal portion, of the catheter body, with receiving features formed on one or more sides thereof. Wherein such receiving features include, e.g., clips, clamps, cradles, projections, prongs, depressions, indentations, notches, grooves, troughs, etc..

In the particular embodiment shown, the elongate member <NUM> comprises an elongate, generally C-shaped member having receiving features <NUM> which comprise spaced-apart transverse notches, recesses or grooves formed along the open side of the generally C-shaped member, as may be appreciated from <FIG> and <FIG>. The heat exchange member(s) <NUM> may be inserted in these recessed, groove, or notch-type receiving features <NUM> such that the helical loops extend around the closed side of the generally C-shaped elongate member <NUM>. The heat exchange member(s) <NUM> may be secured to the receiving features <NUM> by adhesive or other suitable means. Additionally, or alternatively, one or more member(s) may be secured along the open side or within the channels formed by the generally C-shaped elongate member <NUM> so as to capture and retain the heat exchange member(s) <NUM> within the recessed, groove, or notch-type receiving features <NUM>. For example! an elongate luminal member <NUM>, such as a plastic tube, may be affixed to the elongate member <NUM> along its open side after insertion of the heat exchange member(s) <NUM> into the receiving features <NUM>, thereby capturing the heat exchange member(s) <NUM> within the receiving features <NUM> and affixing or securing the heat exchange member(s) <NUM> to the elongate member <NUM>. This may be appreciated from <FIG> and <FIG>. The dimensions of the receiving features can vary to accommodate heat exchange members of various sizes to maximize heat exchange performance and optimize catheter profile. The dimensions of the elongate member, including its open side can vary to accommodate elongate luminal members or through lumens having various sizes to optimize catheter profile. Alternatively, any elongate member may be a shape other than generally C-shaped.

As explained more fully below, the lumen of the optional elongate luminal member <NUM> may serve as a through lumen of the catheter 10b useable for guidewire passage, infusion of medicaments or fluids, insertion of the temperature sensor TS or other functions.

In certain embodiments, the elongate member <NUM> may be molded, notched, or extruded. In certain embodiments, the elongate member <NUM> may be attached to the proximal catheter body <NUM> by any suitable means. In this example, a proximal extension <NUM> of the elongate member <NUM> is inserted into the distal end of the proximal catheter body <NUM> and secured therein by adhesive, clamp or fastener and/or tied or fastened to the catheter body with a plastic tubing, string or other tying mechanism or material (e.g., PET or other type of polymer). The heat exchange member(s) <NUM> may comprise first and second helical, spiral or curved heat exchange segments 30a and 30b formed of noncompliant polymeric material, such as polyethylene terephthalate (PET), Pebax, Polyolefin, Polyurethane and/or Nylon or other suitable compliant or noncompliant material. Segments 30a and 30b may have outer diameters of about <NUM> and <NUM>, respectively, and wall thicknesses of about <NUM>. However, suitable diameters and thicknesses may vary. For example, the diameter of either heat exchange segment may be in the range of <NUM> - <NUM> and the thickness can be in the range of <NUM> - <NUM>. In certain embodiments a heat exchange segment may be formed of polymer material having a diameter of <NUM>" (<NUM>) and a wall thickness of <NUM>" (<NUM>), when empty, the heat exchange segment may be collapsible to a size that will pass through a <NUM> French (<NUM> diameter) or greater introducer, and/or when filled with fluid, the heat exchange segment may assume an expanded configuration having a diameter in the range of from approximately <NUM> inch (<NUM>) to approximately <NUM> inch (<NUM>).

The proximal end of the first segment 30a is connected to the inflow lumen of the catheter body <NUM>. The proximal end of the second segment 30b is connected to the outflow lumen of the catheter body <NUM>. The heat exchange member(s) <NUM> may comprise a single continuous heat exchange tube. Alternatively, the heat exchange member(s) <NUM> may comprise one or more heat exchange tubes. For example, heat exchange segments 30a and 30b may be separate heat exchange tubes, the distal ends of which may be connected to each other by a connection, e.g., a connection tube, lumen or other connecting element.

The first and second heat exchange segments 30a and 30b of heat exchange member <NUM> are disposed on the elongate member <NUM> such that heat exchange fluid will circulate from the inflow lumen of the catheter body <NUM>, in the distal direction through the first heat exchange segment 30a, then in the proximal direction through the second heat exchange segment 30b and into the outflow lumen of the catheter body <NUM>. Alternatively, in other embodiments, heat exchange member <NUM> may be connected to a recirculating tip member through which the heat exchange fluid will circulate from the first segment 30a into the second segment 30b, via the recirculating tip member. One example of such a recirculating distal tip member <NUM> is shown in <FIG> and discussed more fully below. Alternatively, in still other embodiments, the distal end of separate heat exchange tubes 30a, 30b may be connected to a recirculating tip member through which the heat exchange fluid will circulate from the first tube 30a into the second tube 30b.

In the non-limiting example shown in <FIG>, the first heat exchange segment 30a (or the first heat exchange tube if formed of two or more separate heat exchange tubes) has equidistantly spaced helical loops of a first fully-inflated diameter and the second heat exchange segment 30b (or the second heat exchange tube if formed of two or more separate heat exchange tubes) has equidistantly spaced helical loops of a second fully-inflated diameter. The second fully inflated diameter is smaller than the first fully inflated diameter. In other embodiments, the first fully-inflated diameter may be smaller than the second fully-inflated diameter, or the first and second fully-inflated diameters may be equal in size.

The number and diameter(s) of the loops may vary depending on various factors, such as the size of the patient's body, the size of the blood vessel in which the catheter is to be inserted and the heat exchange power required for the intended procedure. In the non-limiting example seen in <FIG> and <FIG>, the heat exchange member has a total of <NUM> loops, the larger loops in the first heat exchange segment 30a has a fully inflated diameter of <NUM> and the smaller loops of the second heat exchange segment 30b has a fully inflated diameter of <NUM>. Also, in this example, loops of the heat exchange segments 30a, 30b are positioned within receiving features <NUM> on the elongate member <NUM>. Such positioning causes the loops to be aligned equidistantly or substantially equidistantly in a single row with the large loops of the first heat exchange segment 30a alternating with the smaller loops of the second heat exchange segment 30b. The receiving features <NUM> of the elongate member <NUM> may be specifically located in the elongate member to guide proper placement of each loop during manufacture, thereby ensuring that the loops are placed in their intended positions with the intended spacing between adjacent loops. In certain embodiments, the number of loops may range from <NUM> to <NUM> loops. A hub <NUM> is mounted on the proximal end PE of the proximal catheter body <NUM>. The hub <NUM> has an inflow connector <NUM> that is connected to the inflow lumen of the catheter body <NUM>, an outflow connector <NUM> that is connected to the outflow lumen of the proximal catheter body <NUM> and a through lumen connector <NUM> that is connected to the optional through lumen of the proximal catheter body <NUM>.

An inflow line IL extends from the heater/cooler <NUM> to the catheter's inflow connector <NUM>. An outflow line OL extends from the catheter's outflow connector <NUM> to the heater cooler <NUM>. One or more temperature leads TL with temperature sensor(s) TS may be positioned in any suitable location(s) on or in the subject's body for sensing of the intended body temperature(s). A temperature lead TL having one or more temperature sensor(s) TS may be inserted through the lumen connector <NUM> and through the catheter 10b. The temperature lead TL serves to connect the temperature sensor(s) TS to the controller <NUM>. Alternatively wireless connectivity may be used instead of the temperature lead TL. In some embodiments, the temperature sensor TS need not be inserted through the catheter 10a as shown in <FIG> but, rather, one or more body temperature sensor(s) TS may be positioned at any other suitable location on or in the subject's body to provide real time feedback of the subject's current body temperature to the controller <NUM>. In some embodiments, a temperature sensor TS may be inserted through a catheter and a second TS may be positioned at any other suitable location on or in the subject's body.

<FIG> show an exploded view of certain components of the endovascular heat exchange assembly <NUM> of catheter 10b. Specifically, <FIG> is a side view of the elongate member <NUM>. <FIG> is a side view of a heat exchange member <NUM> which comprises the first heat exchange segment 30a and second heat exchange segment 30b described above. <FIG> is a side view of an optional elongate luminal member <NUM> and an optional distal tip member <NUM>.

<FIG> show certain steps in a process which may be used for assembling the heat exchange assembly <NUM> of catheter 10b. After the heat exchange member(s) has been set in the looped configuration, elongate member-contacting locations on the loops are inserted in the receiving features <NUM> of the elongate member <NUM>, as shown in <FIG>. Adhesive may be applied to secure each loop within each receiving feature <NUM>. Thereafter, if the optional elongate luminal member <NUM> is to be used, the distal end <NUM> of the elongate luminal member <NUM> is inserted into a distal structure <NUM> of the elongate member <NUM> such that the lumen of the elongate luminal member <NUM> is aligned with an optional bore that extends longitudinally through a distal tip member <NUM>, which may optionally be attached to the distal end of the elongate member <NUM>, as shown in detail in <FIG>. The length of the elongate luminal member <NUM> is then snapped into, mounted on and/or affixed, by adhesive, clamp or fastener and/or tied or fastened with a plastic tubing, string or other tying mechanism or material (e.g., PET or other type of polymer) to the open side of the generally C-shaped elongate member <NUM>, as seen in <FIG> as well as the cross sectional view of <FIG>.

After the heat exchange assembly <NUM> has been assembled, the proximal ends of the heat exchange member(s) <NUM> is/are inserted into and secured to the inflow and outflow lumens of the proximal catheter body <NUM>. Also, if present, the proximal end <NUM> of the optional elongate luminal member <NUM> is inserted into and secured to the optional through lumen of the proximal catheter body <NUM>. Additionally, the proximal extension <NUM> of the elongate member <NUM> is inserted into and secured to the proximal catheter body <NUM>.

<FIG> though 5B show one embodiment of an optional recirculating tip member <NUM> which may be used on certain embodiments of heat exchange catheter described herein, or other types of recirculating fluid catheters. This recirculating distal tip member <NUM> comprises a generally bullet-shaped or blunt-tipped cylindrical structure having a hollow inner cavity <NUM>. An inflow connector <NUM> and outflow connector <NUM> are formed on the proximal end of the recirculating tip member <NUM>. When this recirculating distal tip member <NUM> is mounted on the end of the above-described catheter 10b, the distal end of heat exchange tube 30a will not be directly connected by way of connector <NUM> to the distal end of heat exchange tube 30b. Rather, the distal end of heat exchange tube 30a will be connected to inflow connector <NUM> and the distal end of heat exchange tube 30b will be connected to outflow connector <NUM>. In this manner, heat exchange fluid will flow out of the distal end of heat exchange tube 30a, through inflow connector <NUM>, through the hollow inner cavity <NUM> of the distal tip member <NUM>, through outflow connector <NUM> and into the distal end of heat exchange tube 30b. In catheters which include the optional elongate luminal member <NUM>, the recirculating tip member <NUM> will have optional proximal and distal openings <NUM>, <NUM>. A distal portion or extension of the elongate luminal member <NUM> will be inserted through proximal opening <NUM>, advanced through inner cavity <NUM> and sealed to the distal opening <NUM>, as seen in <FIG>. In this manner, the lumen of the elongate luminal member <NUM> is fluidly isolated from the inner cavity <NUM> of the distal tip member <NUM> such that heat exchange fluid may circulate through the inner cavity <NUM> and around the outer surface of the elongate luminal member <NUM> without entering or leaking into the lumen of the elongate luminal member <NUM>. The recirculating tip member <NUM> may be of multi-piece or single piece construction any may be formed of any suitable material, including radiopaque materials. Examples of materials of which the recirculating tip member <NUM> may be formed include aluminum, <NUM>%/<NUM>% platinum-iridium, and/or ceramic. In certain embodiments, a lumen may extend from proximal opening <NUM>, through inner cavity <NUM>, to distal opening <NUM>, providing a lumen through which an elongate luminal member may extend, which lumen is fluidly isolated from the inner cavity <NUM> of the distal tip member <NUM> such that heat exchange fluid may circulate through the inner cavity <NUM> and around the outer surface of the lumen without entering or leaking into the lumen.

<FIG> shows an alternative embodiment of a heat exchange catheter 10c. In this embodiment, the lumen of the elongate luminal member <NUM> terminates proximal to the distal end of the catheter and is connected to the distal ends of the heat exchange tubes 30a, 30b. As indicated by arrows, heat exchange fluid may be circulated in the distal direction through the lumen of elongate luminal member <NUM> and then in the proximal directions through both of the heat exchange tubes 30a and 30b. This effectively results in distally-directed inflow of heat exchange through a single straight lumen followed by outflow (return) of the heat exchange fluid through both of the looped heat exchanged tubes. The elongate luminal member may be insulated to minimize heat gain or loss as the cooled or warmed heat exchange fluid is being delivered to the distal ends of the heat exchange tubes 30a, 30b. Although this example shows a single inflow lumen with two looped outflow lumens, it is to be appreciated that any number of inflow and outflow lumens may be employed. Optionally, the elongate luminal member may have one or a plurality of lumens. For example, one or more lumens may serve as a through lumen useable for guidewire passage, infusion of medicaments or fluids, insertion of the temperature sensor TS or other functions.

Alternatively, with reference to <FIG>, the flow directions may be inverted such that heat exchange fluid circulates in the distal direction through the looped heat exchange tubes 30a, 30b and then returns in the proximal direction through the lumen of the elongate luminal member <NUM>. Optionally, any of the heat exchange catheter embodiments described herein may include a recirculating tip member <NUM>.

The number and configuration of inflow and outflow lumens used will affect flow rate of the heat exchange fluid and heat exchange power of the catheter. <FIG> show graphic representations of catheter power and flow rate vs. time for several different catheter configurations of the present disclosure in an experimental bench top model representing IVC flow and temperature for the purpose of measuring heat exchange. In this water based model, a catheter is placed in a cylinder up to the manifold (<NUM>). <NUM> water is circulated at a rate of <NUM>/min in the cylinder in the direction of manifold (<NUM>) to balloon (<NUM>). Two thermistors are attached to the catheter. One to the outlet (<NUM>) and one to the inlet (<NUM>) luers. A console that is able to provide 60psi of pressure and saline at ≤ <NUM> fluid is connected to the catheter's luers. On the outlet side of the catheter flow a flow meter is installed. <FIG> shows power and flow versus time for the first embodiment of a heat exchange catheter 10b as shown in <FIG>, wherein the heat exchange member <NUM> has a total of <NUM> loops and wherein heat exchange fluid is pumped in the distal direction through the first heat exchange segment 30a wherein the larger loops are formed and returns in the proximal direction through the second heat exchange segment 30b wherein the smaller loops are formed.

Flow rate is measured by a flow meter positioned at the outlet of the catheter. Power is calculated by the following formula: Power = <NUM>(ΔT * Flow), where temperature T is in Celsius and Flow is in ml/min.

As seen in <FIG>, the first embodiment of the catheter 10b consistently provides power between <NUM> and <NUM> Watts at a substantially constant flow rate of approximately <NUM>/min.

<FIG> is a graph of power and flow versus time in an alternative embodiment of an endovascular heat exchange catheter 10c of the type shown in <FIG>, wherein the looped heat exchange tubes 30a, 30b have a total of <NUM> loops and wherein the heat exchange fluid is circulated in the distal direction through the lumen of the elongate luminal member <NUM> and then returns in the proximal direction through both of the looped heat exchange tubes 30a, 30b.

As seen in <FIG>, this embodiment provides power which increases gradually from approximately <NUM> Watts to approximately <NUM> Watts at a substantially constant flow rate of approximately <NUM>-<NUM>/min.

<FIG> is a graph of power and flow versus time in an alternative embodiment of an endovascular heat exchange catheter 10c of the type shown in <FIG>, wherein the looped heat exchange tubes 30a, 30b have a total of about <NUM> loops, and wherein the heat exchange fluid is circulated in the distal direction through both of the looped heat exchange tubes 30a, 30b and returns in the proximal direction through the lumen of the elongate luminal member <NUM>. In other embodiments, the number of loops may be from <NUM> to <NUM>.

As seen in <FIG>, this embodiment provides catheter power which varies between approximately <NUM> Watts and approximately <NUM> Watts at flow rats which vary between approximately <NUM>/min and approximately <NUM>/min.

<FIG> is a flow diagram which shows steps in an exemplary method for forming the desired loops in the heat exchange member <NUM>. In this method, a shape memory forming member, such as a segment of nickel titanium (Nitinol) wire, is used to impart the desired looped configuration to the heat exchange member <NUM> or any other tube or workpiece having a lumen that extends therethrough. Initially, the heat exchange member, tube or other workpiece in which loops are to be created is advanced over the forming member while the forming member is in a non-looped (e.g., substantially straight) initial configuration. Thereafter, the forming member is caused to transition from its initial configuration to the desired looped configuration, thereby also causing the heat exchange member, tube or other workpiece to assume such looped configuration. Thereafter, the forming member is removed from the heat exchange member, tube or other workpiece while the member, tube or other workpiece is maintained in the looped configuration. In this manner, loops of the desired number, size, shape and spacing may be formed in the heat exchange member <NUM> and/or tubes 30a and 30b or other tube or luminal workpieces. In some embodiments, the forming member may be formed of a shape memory nickel-titanium alloy or other material and the step of causing the forming member to transition from its first configuration to the desired second configuration may be accomplished by changing the temperature of the forming member to cause the forming member to transition from the first shape to the second shape. For applications where the method is used to induce the desired looped configuration to the heat exchange member <NUM> or tubes 30a, 30b of catheters of the present disclosure, the forming member may comprise a nickel-titanium alloy wire formed of e.g., Nitinol that is <NUM>/<NUM> by weight of Titanium and Nickle having a shape memory transition temperature of about <NUM> - <NUM> degrees C or below <NUM> degrees and/or above <NUM> degrees. In an alternative embodiment, the shape memory forming member may be in the form of a tube. The tube has a lumen in which the heat exchange member would be inserted. This tube shape memory forming member would transition between a straight and looped configuration, thereby imparting the desired looped configuration in the heat exchange member.

In certain examples, materials such as PEBAX and PET may be used in the construction of one or more of the catheters or catheter components described herein. For example, materials such as PEBAX and PET may be used in the construction of the catheter body, the elongate member or spine and/or the heat exchange member. Optionally, a catheter may include or be reinforced with a non-ferrous or MRI compatible material, such as Tevlar, Tedlar™ (polyvinyl fluorides, E. Dupont, Wilmington, Delaware, USA), liquid crystal polymer, PEEK or other non-ferrous high temperature polymers. These materials may be used to create a braid or coil reinforcement in the catheter.

The heat exchange catheters described herein provide a number of advantages over existing heat exchange catheters. For example, the elongate member or spine <NUM> may provide the rigidity or column strength necessary to advance the heat exchange assembly <NUM> to the intended location within the subject's vasculature. The elongate member <NUM> may make it easier to manufacture the catheter 10b, compared to tying the balloon around an extended guidewire lumen or other member. The elongate member may be injected molded with teeth/grooves or other receiving features for receiving the heat exchange member, tube or balloon which hold each loop of a heat exchange member, tube or balloon in place, and maintain spacing between the loops. This may be especially advantageous when working with a heat exchange member, tube or balloon having looped supply and return lumens with many loops. The elongate member <NUM> may allow the heat exchange assembly <NUM> to have a relatively small cross sectional profile when deflated (e.g., <NUM> to <NUM> French (<NUM> to <NUM>) or <NUM> to <NUM> French (<NUM> to <NUM>) or <NUM> French (<NUM>). Also, the receiving features <NUM> of the elongate member <NUM> maintain spacing of the loops, thereby making the heat exchange member(s) <NUM> less obstructive within the vessel. This may allow for better blood flow through and around the balloon and decrease the risk of blood clot formation compared to a more obtrusive catheter construction in which the heat exchange member(s) are wrapped around a catheter body or adjacent loops of a heat exchange member are not evenly spaced apart. The heat exchange catheters, systems and methods described herein may provide high-efficiency heat exchange and the ability to rapidly raise or lower a patient's body temperature.

Claim 1:
A catheter device comprising:
a catheter body (<NUM>) having a distal end, a first lumen and a second lumen;
an elongate member (<NUM>) which extends distally from the catheter body, said elongate member having a plurality of spaced-apart heat exchange member-receiving features (<NUM>) therein or thereon, wherein the plurality of spaced-apart heat exchange member-receiving features comprises open areas transversing the elongate member along a first transverse axis (<NUM>) configured to receive the heat exchange member along a second transverse axis orthogonal to the first axis; and
at least one heat exchange member (<NUM>) disposed on the elongate member, wherein the at least one heat exchange member is fully or partially positioned within the plurality of spaced-apart heat exchange member-receiving features, wherein the at least one heat exchange member is further connected to said first and second lumens such that fluid may circulate in a distal direction through the first lumen, then through said at least one heat exchange member, then in a proximal direction through the second lumen.