Patent Publication Number: US-11660425-B2

Title: Perfusion catheters and related methods

Description:
CLAIM OF PRIORITY 
     This non-provisional patent document is a continuation of U.S. patent application Ser. No. 16/414,921, entitled “PERFUSION CATHETERS AND RELATED METHODS” and filed May 17, 2019, now U.S. Pat. No. 11,027,102, which claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 62/701,362, entitled “PERFUSION CATHETERS AND RELATED METHODS” and filed on Jul. 20, 2018, each of which is herein incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The subject matter of this patent document relates to the field of medical devices. More particularly, but not by way of limitation, the subject matter relates to catheters and related methods for sealing a vessel perforation or dissection or dilating a vessel occlusion. 
     BACKGROUND 
     A severe or chronic total occlusion (CTO) is a vessel blockage that prevents blood flow beyond the occlusion. Chronic total occlusions most often occur in coronary and peripheral arteries and result from atherosclerosis. 
     A procedure for treating CTOs is percutaneous transluminal angioplasty. 
     During an angioplasty procedure, access to a desired blood vessel is obtained and a guidewire is introduced into the blood vessel. The guidewire is maneuvered into place, including being passed into and through the occlusion, and acts as a guide for positioning a subsequent treatment device used to dilate or otherwise treat the vessel occlusion. The treatment device can be advanced over the guidewire so that its distal portion is positioned within the occlusion. A dilatation balloon at the distal portion of the treatment device can then be inflated to apply radial pressure to the occlusive material and adjacent inner wall portions of the vessel, thereby clearing the occlusion to enable better blood flow. 
     OVERVIEW 
     The present inventors recognize that CTOs are one of the most challenging lesion subsets in interventional cardiology to treat due to their established occlusive structure. Complications related to CTO interventions include vessel wall perforation and dissection. If not treated without delay, blood hemorrhaging through the perforation or dissection can lead to death of the patient within minutes. 
     The present inventors also recognize that sealing of the vessel perforation or dissection using conventional balloon catheters causes complete interruption of blood flow within the damaged vessel while the catheter&#39;s balloon is inflated. Keeping the balloon inflated for an extended period can risk damage to bodily regions nourished by the vessel-regions already weakened by insufficient blood supply. For example, prolonged dilations of several minutes may need to be employed to effectively treat a perforation. Yet, most adults are only able to withstand non-perfusion dilation of 30-60 seconds without significant side effects. 
     The present inventors further recognize that after treating a vessel, the catheter balloon may not sufficiently deflate, making it difficult or even impossible to pull the balloon back into the guide catheter and remove it from the patient. The inventors particularly recognize that fluid remaining in the balloon is often pushed distally as the balloon is pulled proximally into the guide catheter, thereby trapping fluid in the balloon and preventing complete deflation, which also increases the likelihood of puncturing the balloon. 
     The present perfusion catheters can be quickly and easily deployed, inflated, and deflated in a damaged vessel. The catheters can also provide a passage (or flow lumen) formed upon inflation of its balloon. A perfusion catheter can include a balloon formed of an inflatable tube and an elongate shaft having a lumen for providing inflation fluid to, or withdrawing inflation fluid from, the balloon. The inflatable tube can be coiled in a helical manner around a central axis into a series of windings. Adjacent windings can be stacked against and bonded to each other or laterally spaced, and an inner surface of the series of windings, when inflated, can define the passage. The elongate shaft can be eccentrically attached to a distal portion of the balloon and its lumen can be in fluid communication with the interior of the inflatable tube. The inflatable tube can include two different polymer tubes, one slightly smaller than the other. The smaller, inner tube can be formed from a polymer having sufficient radial stiffness to resist collapse or bursting when exposed to inflation pressures, and the larger, outer tube can be formed from a polymer configured to exhibit adhesive properties when heated. 
     The present methods for sealing a perforation or dissection or dilating occlusive material can include inserting a guidewire into a blood vessel and advancing the guidewire to or across a treatment site, passing a perfusion catheter over the guidewire until a distal portion of the perfusion catheter is positioned near or within the treatment site, and inflating a balloon of the perfusion catheter. Inflating the balloon can include inflating a series of windings of helically-wound tubing, which may be contacting or laterally spaced. The balloon, upon inflation, can move from a deflated configuration to an inflation configuration at which an outer surface of the balloon can engage a wall of the blood vessel and an inner surface of the balloon can define a passage. The passage can allow a flow of bodily fluid, such as blood, through the perfusion catheter. Optionally, the method can include passing a treatment device at least partially through the passage. After treatment, the balloon can be deflated in a distal-to-proximal direction and removed through the guide catheter. 
     Objects of the present perfusion catheters and related methods include, among others: 
     1. Sealing a vessel perforation or dissection by blocking the injury from inside the vessel for an extended period of time while maintaining a sufficient flow of blood through a treated vessel segment; 
     2. Dilating a vessel occlusion for an extended period of time while maintaining a sufficient flow of blood through a treated vessel segment; 
     3. Delivering or receiving one or more treatment devices while sealing a vessel perforation or dissection or dilating a vessel occlusion; and/or 
     4. Cleanly removing all treatment devices. 
     These and other examples and objects of the present perfusion catheters and related methods will be set forth in the following Detailed Description. This Overview is intended to provide non-limiting examples of the present subject matter—it is not intended to provide an exclusive or exhaustive explanation. The Detailed Description below is included to provide further information about the present perfusion catheters and related methods. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, like numerals can be used to describe similar features and components throughout the several views. The drawings illustrate generally, by way of example but not by way of limitation, various embodiments discussed in the present patent document. 
         FIG.  1    illustrates a schematic view of a guidewire advanced through a patient&#39;s vasculature and unable to penetrate an end cap of an occlusion within a vessel. 
         FIG.  2    illustrates a schematic view of a distal portion of a treatment device dilating an occlusion within a vessel segment, such dilation causing dissection of the vessel&#39;s wall. 
         FIG.  3    illustrates a side view of a perfusion catheter, as constructed in accordance with at least one embodiment. 
         FIG.  4    illustrates an enlarged side view of a distal portion of a perfusion catheter including a dedicated guidewire lumen, as constructed in accordance with at least one embodiment. 
         FIG.  5    illustrates an enlarged cross-sectional view of a distal portion of the perfusion catheter taken along line A-A of  FIG.  4   . 
         FIG.  6    illustrates an enlarged cross-sectional view taken along line B-B of  FIG.  5   . 
         FIG.  7 A  illustrates an enlarged cross-sectional view taken along line C-C of  FIG.  5   . 
         FIG.  7 B  illustrates an enlarged cross-sectional view taken at detail AB of  FIG.  7 A . 
         FIG.  7 C  illustrates an enlarged cross-sectional view taken at detail AA of  FIG.  7 A . 
         FIG.  8    illustrates an enlarged side view of a distal portion of the perfusion catheter shown in  FIG.  4   , with its balloon in a deflated configuration within a vessel segment. 
         FIG.  9    illustrates an enlarged side view of a distal portion of the perfusion catheter shown in  FIG.  4   , with its balloon in an inflated configuration within a vessel segment. 
         FIG.  10    illustrates an enlarged side view of a distal view of a distal portion of a perfusion catheter including a dedicated guidewire lumen, as constructed in accordance with at least one embodiment. 
         FIG.  11    illustrates a cross-sectional view taken along line D-D of the extruded tubing shown in  FIG.  10   . 
         FIG.  12    illustrates a mandrel for manufacturing a balloon of a perfusion catheter, as constructed in accordance with at least one embodiment. 
         FIG.  13    illustrates a side view of an elongate shaft of a perfusion catheter, as constructed in accordance with at least one embodiment. 
         FIG.  14    illustrates a cross-sectional view taken along line E-E of the elongate shaft shown in  FIG.  13   . 
         FIG.  15    illustrates a method of using a present catheter to navigate through vasculature, as constructed in accordance with at least one embodiment. 
     
    
    
     The drawing figures are not necessarily to scale. Certain features and components may be shown exaggerated in scale or in schematic form and some details may not be shown in the interest of clarity and conciseness. 
     DETAILED DESCRIPTION 
     With the advancement of medical devices and increased training, clinicians are treating CTOs using angioplasty techniques more than ever before. The present catheters and methods provide the clinicians with a means to treat complications related to CTO angioplasty interventions or to dilate a vessel occlusion while maintaining a passage through the treated vessel segment. The present catheters and methods also provide the clinicians with a means to safely and effectively remove all interventional devices after treating a CTO. While the catheters and methods are primarily discussed in relation to treatment of coronary arteries, they may also be useful in other blood vessels throughout the body including peripheral arteries and veins. 
       FIGS.  1  and  2    provide examples of complications related to CTO angioplasty interventions in which the present perfusion catheters and related methods can be beneficial. In patients suffering from a CTO, successful treatment of the occlusion can be challenging. A factor that can determine whether a treating clinician can successfully treat the occlusion is the clinician&#39;s ability to advance a guidewire from a first side of the occlusion to a second side of the occlusion. In some instances, such as when the natural lumen  102  of a blood vessel  104  is totally occluded by hard plaque  106  (e.g., calcified atherosclerotic plaque), the guidewire  108  cannot cross the occlusion and, in response to a continued proximally-applied pushing force  110 , its distal portion  112  may deviate to, and perforate  114 , an adjacent vessel wall  116 , as shown in  FIG.  1   . 
     In other instances, such as when the occlusive material  206  is soft or where the occlusion has a tiny opening, the guidewire  208  can be forced through the occlusive material and allowed to remain within the natural lumen  202  of the blood vessel  204 . A treatment device, such as a balloon catheter  218 , can be guided over the guidewire  208  to the occlusion site where it can be used to carry out dilation treatment. Mechanical dilatation of the vessel  204  with the balloon catheter  218  can be associated with plaque fracture, intimal wall splitting, and localized medial dissection. Dissection  220 , if it occurs, may propagate into the media and through the adventitia (the outermost layer of the vessel wall), resulting in another form of coronary perforation as shown in  FIG.  2   . 
     Perforations and dissections are serious complications for a catheterization laboratory because of their associated morbidity and mortality rates and, for this reason alone, their management and treatment is important and should be initiated quickly. A first step in management and treatment can be the placement of a balloon to seal the perforation or dissection. Prolonged balloon inflation may successfully seal the perforation or stop the propagation of the dissection and can provide time to prepare and implant a covered stent, if needed. 
     The present perfusion catheter  300  can be used in cases where there is a vessel perforation or dissection to be treated and further in cases where there is occlusive material to be dilated. The catheter  300  can be advanced through a guide catheter and directed through vasculature for treatment of the vessel wall injury using a guidewire and optionally a placement catheter. The perfusion catheter  300  can include a proximal manifold  324  for coupling with an inflation syringe, an elongate shaft  326 , and a distal balloon  328  to seal the perforation or dissection or dilate the occlusive material. 
     The elongate shaft  326  can serve two primary purposes. First, the elongate shaft  326  can transmit forces applied by a clinician to either advance or retract the perfusion catheter  300 , and specifically the balloon  328 , during an angioplasty or sealing procedure. By manipulating the elongate shaft  326 , the balloon  328  can be inserted into and passed through a guide catheter and out the distal portion of the guide catheter to a perforation or dissection to be sealed or an occlusion to be dilated. Second, the elongate shaft  326  includes a lumen  330  for providing inflation fluid to, or withdrawing inflation fluid from, the balloon  328 . The lumen  330  of the elongate shaft  326  can be in fluid communication with the manifold  324 , couplable to an inflation syringe, at its proximal portion  332 , and it can be in fluid communication with the interior of the balloon  328  near its distal portion  334 . 
     The elongate shaft  326  can be eccentrically attached to a distal portion  336  of the balloon  328  and can extend proximally for clinician accessibility outside the guide catheter. The elongate shaft  326  can be attached to the balloon  328  by wrapping the balloon  328  about the shaft&#39;s intermediate  338  or distal  334  portions and affixing it thereto. In an example, the elongate shaft  326  is attached to the distal portion  336  of the balloon  328  for a minimum of 5 mm. 
     The embodiment of  FIG.  3    illustrates that the balloon  328  can be formed from an inflatable tube  340  coiled in a helical or spiral manner around a central axis into a series of windings  342  (or loops), with consecutive or adjacent windings  342 . The windings  342  may be stacked against and contacting each other with substantially no space therebetween, which can ensure the windings  342  act as a unit. Alternatively, the windings  342  may be spaced apart such that adjacent windings do not contact each other. Spaced windings  342  may be preferred for non-coronary applications, which may involve positioning the balloon  328  in veins of greater diameter. The inner surfaces of the windings  342  can define a passage  344  through the open center of the helix when the coiled balloon  328  is inflated. The passage  344  can extend the full length of the balloon  328  to permit blood or other fluid to perfuse (or flow) therethrough, which is important since cutting off blood supply for extended periods of time is undesirable. When the balloon  328  is deflated, it can collapse or flatten into a low profile configuration, which may comprise one or more folds that wrap around the distal portion  334  of the elongate shaft  326 . An elastic sheath can optionally be disposed around the balloon  328  and be utilized to reduce the collapsed profile of the deflated balloon so that it can be more easily inserted or removed from a patient. 
     Because the passage  344  is created by the balloon  328 , blood flow is permitted through the passage  344  and the overall perfusion catheter  300  can be kept to a minimal size. This physical attribute allows the catheter  300  to be of a small diameter when it is inserted into the patient&#39;s body and maneuvered to the desired position, yet provides a relatively large blood flow passage when the balloon  328  is inflated. 
       FIG.  4    illustrates an enlarged side view of a distal portion of a perfusion catheter  400 , as constructed in accordance with at least one embodiment. The catheter  400  can be provided with a guidewire lumen  452  separate from a passage  444  defined by windings  442  of a balloon  428  and separate from a lumen  430  of an elongate shaft  426  for providing inflation fluid to, or withdrawing inflation fluid from, the balloon  428 . In the example shown, the windings  442  are stacked against each other, but in additional embodiments, the windings can be spread apart, such that a lateral space  443  is defined between them. The guidewire lumen  452  can have a length  454  approximately equal to, or slightly longer than, the length  448  of the passage  444  and can be positioned therein. An outer surface of a guidewire support tube  456  forming the guidewire lumen  452  can contact inner surfaces of the windings  442  of the balloon  428  and can optionally be inset in these inner surfaces. Polymers of the guidewire support tube  456  and the balloon  428  can be configured to adhere to each other upon application of heat treatment. A proximal end  457  of the guidewire support tube  456  may defined a skived entry configured to receive the guidewire in some examples. In various examples, the proximal end  457  may define a length  453  ranging between 2 mm and 5 mm, inclusive. In some embodiments, the elongate shaft  426  and the proximal end  429  of the balloon  428  may be fused together along a distance  463  of the guidewire lumen  452 . 
     A distal end  436  of the balloon  428  is fluidly coupled with a distal end  431  of the lumen  430  of the elongate shaft  426 , such that inflation fluid is added and removed at the distal end  436  of the balloon. The balloon  428  can be helically coiled proximally from its distal end  436 , and a proximal end  429  of the balloon  428  may comprise a tail portion wrapped around the inflation lumen  430 , thereby sealing the proximal end  429 . Proximal wrapping of the balloon  428  may be implemented without heat shrinking or adhesive application in various implementations. Because the proximal end  429  of the balloon  428  can be sealed and inflation fluid can only be removed via its distal end  436 , deflation of the balloon  428  may occur in a distal-to-proximal direction, in the direction of the arrow toward a guide catheter  455 . Accordingly, when the catheter  400  is deflated and pulled proximally back into a guide catheter, the inflation fluid may not become trapped or sequestered in any portion of the balloon  428 . This facilitates effective and safe removal of the catheter  400  from a treatment site, for example by decreasing the cross-sectional diameter of the deflated balloon. Complete deflation may also reduce the risk of puncturing or tearing the balloon  428  upon its reentry into the guide catheter  455 . In examples, a maximum distance  433  of about 2 mm of the balloon may not be reflowed. 
     The guidewire lumen  452  can be designed to receive and facilitate tracking of a previously positioned guidewire having its distal portion in position near or across a treatment site. The perfusion catheter  400 , and specifically the guidewire support tube  456 , can be slid over the guidewire and advanced to the treatment site. An inner diameter of the guidewire support tube  456  can be sized to be advanced over a 0.36 mm (0.014 in) guidewire, for example. An atraumatic distal end portion  458  culminating in a tapered tip  459  can be disposed at a distal tip of the guidewire support tube  456  to prevent the perfusion catheter  400  from perforating a blood vessel during deployment and use. In various examples, a proximal portion of the distal end portion  458  can be distally offset by a distance  465  ranging from about 0.1 mm-5 mm. Since the guidewire support tube  456  can be short compared to the total lengths of the catheter  400  and the guidewire, the use of the guidewire support tube  456  as a guide permits rapid exchange of the catheter  400  over the guidewire. 
     One or more radiopaque markers  460  can be placed on the guidewire support tube  456  or the elongate shaft  426  proximal or distal to the balloon  428 . These markers  460  can facilitate proper placement of the balloon  428  relative to a vessel wall injury prior to its inflation and can be any suitable radiopaque material detectable through the use of x-ray or fluoroscopy. Materials such as the platinum series of metals (e.g., platinum or palladium), gold, silver, iridium, or tantalum can be used as the markers. Certain stainless steels can also be suitable for use as markers. Alternatively, the polymer used in portions of the perfusion catheter  400  can be radiopaque or made so by addition of filler such as barium sulfate, bismuth trioxide, bismuth carbonate, tungsten, tantalum, or the like. 
       FIG.  5    illustrates a cross-sectional view of a catheter  500  (taken along line A-A of  FIG.  4   ). As shown, the inflation lumen  530  of the elongate shaft  526  can longitudinally span the length of the balloon  528 , such that each of the plurality of windings  542  covers the elongate shaft  526 . The guidewire support tube  556  can extend for a distance beyond the distal end of the elongate shaft. In the embodiment shown, the distal end portion  558  of the guidewire support tube  556 , including the tapered tip  559 , can define a length  561  of about 3 mm. The length  561  may vary in examples, ranging from about 1 mm to about 6 mm, about 2 mm to about 5 mm, or about 1.5 mm to about 4.5 mm. The diameter or width  563  of the distal end portion  558  may also vary. In various embodiments, the maximum width of the distal end portion may be about 0.038 in. The minimum width may be adjustable, provided the width is sufficient to accommodate a guidewire for various applications. In examples, the width  563  may range from about 0.01 in to about 0.05 in. 
       FIG.  6    illustrates a cross-sectional view of an inflated balloon  628  and a guidewire support tube  656  and elongate shaft  626  extending therethrough, taken along line B-B of  FIG.  5   . The guidewire support tube  656  and the elongate shaft  626  can be inset or embedded within a radial portion of the inflatable tube comprising the balloon  628 , leaving the internal passage  644  unobstructed upon inflation of the balloon  628 . In examples, the balloon windings can be bonded directly to the guidewire support tube  656  for the full length of the balloon, such that the guidewire lumen  652  and inflation lumen  630  are fully enveloped by the balloon. In some embodiments, an outer surface of the elongate shaft  626  and the distal end of the inflatable balloon  628  can be affixed by a heat treatment process such that the shaft&#39;s lumen is in fluid communication with an interior of the balloon. 
     The inner diameter  657  of the inflated balloon  628  can accommodate passage of various treatment devices, e.g., stents, therethrough. The inner diameter  657  may be about 3 mm in some examples, and can range in additional implementations from about 1 mm to about 6 mm, about 2 mm to about 5 mm, or about 1.5 mm to about 4.5 mm. The outer diameter  659  can also vary, depending for example on the diameter of a vessel at the targeted treatment site. In various embodiments, the outer diameter  659  can range from about 2 mm to about 8 mm, about 3 mm to about 6 mm, about 3.5 mm to about 5 mm, about 3.75 mm to about 4.25 mm, or about 4 mm. 
       FIG.  7 A  illustrates a cross-sectional view of a catheter  700 , taken along line C-C of  FIG.  5   . As shown, the elongate shaft  726  and guidewire support tube  756  can be positioned adjacent to each other, each embedded within the balloon  728 .  FIG.  7 B  provides an enlarged view of detail AB, showing where the fluid connection between a distal portion  734  of the elongate shaft  726  and a distal portion  736  of the balloon  728  can be established, proximal to the distal end portion  758  of the guidewire support tube  756 .  FIG.  7 C  provides an enlarged view of detail AA, showing the proximal end  729  portion of the balloon, which in the example shown, comprises a tail portion wrapped around the inflation lumen  730 . 
       FIG.  8    illustrates a perfusion catheter  800  in a blood vessel  804  of a patient. The catheter  800 , and specifically a balloon  828  of the catheter, can be introduced and advanced within the blood vessel  804  in a low profile, unexpanded configuration. In this configuration, the balloon  828  is in a relaxed, folded, or crushed configuration and does not significantly increase the overall diameter of a distal portion of the catheter  800  such that it can be inserted into the patient and guided through the patient&#39;s vasculature to the desired treatment site. 
     Once at the treatment site, the balloon  928  can be inflated as illustrated in  FIG.  9   . Fluid under pressure can be supplied to the balloon  928  through an inflation lumen  930  of an elongate shaft  926 , thereby expanding the balloon  928  toward a wall  916  of the blood vessel  904 , such as for sealing, opening, or otherwise treating it. When inflated, the balloon  928  can impinge upon or engage the vessel wall  916  at the treatment site at pressures of 2 atm-20 atm, for example, yet blood can be allowed to flow through the passage  944  defined by the balloon&#39;s windings  942 . Since the passage  944  created through the windings  942  is relatively large compared to the size of the vessel  904 , the interruption of blood flow through the vessel is minimized and the perfusion catheter  900  is capable of prolonged inflation for temporary hemostasis in coronary perforations or dissections. 
     Beyond allowing for fluid flow, the passage  944  of the balloon  928  can be adapted to slidably receive a treatment device (e.g., a smaller diameter balloon catheter, stent catheter, guidewire support catheter, or guidewire). The balloon  928  can include any number of windings  942  in a number of sizes and configurations depending upon the particular treatment site, procedure and/or patient. Increasing the number of windings  942  in the balloon  928  can increase the ability of the balloon  928  to maintain a dilated state of an occlusion. The passage  944  can have a diameter  946  ranging from 2 mm-6 mm and can extend 10 mm-50 mm in length  948 , for example. The diameter  946  of the passage  944  can be sufficiently large to permit entry of a stent catheter. The present inventors recognize that plaque has a tendency to return to its original form and restrict passage. This restenosis, if it occurs, can occur as quickly as a few minutes. The perfusion catheter  900  allows the stent catheter to be delivered through the catheter while the balloon  928  dilates the occlusion. In this way, there can be minimal time between occlusion dilation and placement of a stent. The diameter  946  of the passage  944  can be sufficiently large to receive a guidewire support catheter to help pre-dilate or otherwise establish a pilot opening through the occlusion, or to receive the distal portion of a retrograde guidewire that is funneled into the passage  944  as a result of engagement between an outer surface  950  of the balloon  928  and the vessel wall  916 . 
     When the procedure is completed, the balloon  928  can be deflated by applying vacuum to a proximal manifold coupled with the inflation lumen  930  of the elongate shaft  926 . The entire perfusion catheter  900  can then be removed. 
       FIGS.  10  and  11    respectively illustrate side and cross-sectional views of extruded tubing  1040  for use in a balloon of a perfusion catheter, as constructed in accordance with at least one embodiment. The extruded tubing  1040  can have a uniform outer diameter along its length  1062  or can have a larger diameter along a majority of its length and tapered down on its proximal  1064  and distal  1066  portions. The length  1062  of the extruded tubing  1040  can range from 40 cm-120 cm before being coiled in a helical or spiral manner into a series of windings. 
     The coiled shape of the balloon can be maintained by causing adjacent windings to adhere to one another, in some examples, and the integrity of the balloon can be internally provided within each winding. These qualities can be accomplished by coextruding a combination of nested polymers which, after winding of the coil, can be heat treated to allow adjacent coils to stick to each other. In the example of  FIG.  11   , the extruded tubing  1140  is formed by coextruding two different polymer tubes  1168 ,  1170  (or layers), one slightly smaller than the other. The coextrusion process can eliminate seams, which are found in existing balloon designs, form tight bonds, and create a balloon using a reduced number of manufacturing steps. Alternatively, the smaller tube  1168  can be inserted inside the larger tube  1170  post-extrusion. 
     The smaller, inner tube  1168  can be formed from a polymer having sufficient radial stiffness to resist collapse or bursting when exposed to inflation pressures, and the larger, outer tube  1170  can be formed from a polymer configured to exhibit adhesive properties when heated and compliant properties when used within the body. In some examples, the adhesive properties of the outer tube  1170  can allow adjacent windings to adhere to one another. The use of a compliant material for the outer tube  1170  can enable the balloon to conform to a vessel wall at the site of a perforation or tear, so that a substantial portion of the balloon&#39;s outer surface can be compressed against the vessel wall, or at the site of an occlusion that can benefit from being dilated. In various examples, the inner tube  1168  can include polyethylene terephthalate (PET) or PEBAX polyether block amides (which are available from Arkema) having an outer diameter of 0.2 mm-0.28 mm and an inner diameter of 0.12 mm-0.18 mm, and the outer tube  1170  can include HYTREL polyester elastomer (which is available from E.I. du Pont de Nemours and Company), PEBAX, or nylon having an outer diameter of 0.28 mm-0.36 mm and an inner diameter of 0.20 mm-0.28 mm. The inner  1168  and outer  1170  tubes can include polymers having different melting or softening temperatures, with the inner tube  1168  including the polymer with the higher melting temperature. The inner  1168  and outer  1170  tubes can include the same or similar polymers, with the polymer of the inner tube  1168  being cross-linked for strength and with the polymer of the outer tube  1170  not being cross-linked. 
       FIG.  12    illustrates a mandrel  1272  for coiling extruded tubing in a helical manner around a central axis into a series of windings to form a balloon. The extruded tubing can be wrapped in a proximal direction about the mandrel  1272 , which includes a shape of the intended profile of the balloon. After being wrapped onto the mandrel  1272 , the extruded tubing can be pressurized or inflated and adjacent windings can be heat set in order to ensure that they adhere to one another and the balloon maintains its coiled shape. For example, heat setting the coiled configuration of the balloon can include causing the outer surface of adjacent windings of the extruded tubing to adhere to one another via heating the tubing or the mandrel  1272 . The extruding tubing can then be cooled to room temperature. In additional examples, adjacent windings may not be heat set in order to ensure that the windings remain laterally spaced from each other upon inflation. 
       FIGS.  13  and  14    respectively illustrate side and cross-sectional views of an elongate shaft  1326 ,  1426  of a perfusion catheter, as constructed in accordance with at least one embodiment. The elongate shaft  1326 ,  1426  can include a lumen  1430  extending from a proximal portion  1332  to an inflation port for providing inflation fluid to, or withdrawing inflation fluid from, a distal end of a distal balloon. The elongate shaft  1326 ,  1426  can extend a length  1374  of 100 cm-200 cm and can possess the qualities of compression rigidity along its longitudinal axis, which facilitates advancement of the perfusion catheter through a patient&#39;s vascular system, and good distal flexibility, which enhances maneuverability of catheter through directional changes of the vascular system and prevents damage to the vessel walls as it is being inserted. Portions of the elongate shaft  1326 ,  1426  can include a PTFE coating  1376  to facilitate its advancement through the patient&#39;s vascular system. 
     These qualities are achievable in a variety of ways. In an example, proximal  1332  and intermediate  1338  portions of the elongate shaft  1326 ,  1426  can include a stainless steel hypotube  1377 ,  1477 , and the distal portion  1334  can include a stainless steel support wire  1379 ,  1479  or tube that is connected for a length  1375  to the intermediate portion. The support wire  1379 ,  1479  can help transmit forces applied by a treating clinician to either advance or retract the balloon during a treatment procedure. The support wire  1379 ,  1479  can range in length from 10 cm-20 cm and can be secured to the hypotube  1377 ,  1477  via a laser weld. The support wire  1379 ,  1479  can extend to a location distal to the balloon or can terminate between the balloon&#39;s proximal and distal portions. In another embodiment, the elongate shaft  1326 ,  1426  can be formed from a single piece of metallic or polymer tubing with a proximal portion that has an outer and inner diameter larger than an outer and inner diameter of a distal portion or with a proximal portion having greater wall thickness than a distal portion. 
     A means to affix an outer surface  1378  of the elongate shaft  1326 ,  1426  and the flexible material of the balloon can be employed to withstand stresses associated with pressure changes of inflation and deflation of the balloon. It can be important that the affixing means create a fluid tight seal between the two materials and restrict any delamination along the seal line during prolong periods of working pressures. In an example, portions of the elongate shaft  1326 ,  1426  coupled with the balloon can be covered with nylon (e.g., VESTAMID L2101) as part of the affixing means. The materials can be joined by an adhesive process, such as a cyanoacrylate, epoxy or urethane compounds, or joined by a heat treatment or pressure fit process that melts or welds the two materials together. 
       FIG.  15    illustrates a method  1500  of using a perfusion catheter in a coronary vessel for sealing a perforation or dissection or dilating occlusive material while maintaining a passage. 
     At  1582 , the method involves passing a perfusion catheter, including a balloon and an elongate shaft that is attached to the balloon, into a blood vessel until the balloon is positioned adjacent a perforation or dissection in a wall of the blood vessel. 
     At  1584 , the method involves inflating the balloon to seal the perforation or dissection in the wall of the blood vessel. Inflation of the balloon can include urging fluid through a lumen of the elongate shaft and into the balloon to inflate a series of helical windings. 
     At  1586 , the method specifies that the balloon, upon inflation, moves from a deflated configuration to an inflated configuration at which an outer surface of the balloon engages the wall of the blood vessel and an inner surface of the balloon&#39;s series of helical windings defines a passage. 
     At  1588 , the method involves, after inflating the balloon, passing a treatment device at least partially through the passage. The treatment device can be received in a distal-to-proximal direction or delivered in a proximal-to-distal direction. 
     At  1590 , the method involves deflating the balloon by withdrawing fluid from the balloon in a distal-to-proximal direction of the balloon. 
     At  1592 , the method involves retracting the perfusion catheter from the blood vessel. Additional or alternative steps may be incorporated into method  1500  in accordance with the present disclosure. 
     CLOSING NOTES 
     The above Detailed Description includes references to the accompanying drawings, which form a part of the Detailed Description. The Detailed Description should be read with reference to the drawings. The drawings show, by way of illustration, specific embodiments in which the present catheters and related methods can be practiced. These embodiments are also referred to herein as “examples.” 
     The Detailed Description is intended to be illustrative and not restrictive. For example, the above-described examples (or one or more features or components thereof) can be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above Detailed Description. Also, various features or components have been or can be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter can lie in less than all features of a particular disclosed embodiment. Thus, the following claim examples are hereby incorporated into the Detailed Description, with each example standing on its own as a separate embodiment: 
     In a first example, a perfusion catheter can include an inflatable balloon coiled in a helical manner around a central axis into a series of windings. An inner surface of the series of windings, when inflated, can define a passage through the inflatable balloon. The catheter can also include an elongate shaft extending from a proximal portion to a distal portion, having an inner surface that defines a lumen for providing inflation fluid to, or withdrawing inflation fluid from, a distal end of the inflatable balloon. The catheter can further include a guidewire support tube including a lumen, separate from the lumen from the elongate shaft and the passage through the inflatable balloon, for receiving a guidewire. 
     In some examples, the perfusion catheter can optionally be configured such that the guidewire support tube is inset in the inner surface of the series of windings. In some examples, the perfusion catheter can optionally be configured such that an outer surface of the elongate shaft and the distal end of the inflatable balloon are affixed by a heat treatment process such that the shaft&#39;s lumen is in fluid communication with an interior of the balloon. In some examples, the passage can have a diameter ranging from 2 mm-6 mm and a length ranging from 10 mm-50 mm. In some embodiments, the elongate shaft can be eccentrically positioned relative to the inflatable balloon such that the elongate shaft does not protrude radially into the passage. In some examples, a proximal portion of the inflatable balloon can wrap around the elongate shaft, such that the proximal portion is sealed. In some examples, the guidewire support tube and the elongate shaft can be inset in the inner surface of the series of windings. In some examples, the inflatable balloon can be configured to deflate in a distal-to-proximal direction. In some examples, the inflatable balloon can include concentric inner and outer tubes, a polymer of the inner tube can be cross-linked, a polymer of the outer tube can be non-cross-linked, and the polymer of the inner tube can have sufficient radial stiffness to resist bursting when exposed to inflation pressure. In some examples, adjacent windings of the series of windings can be stacked against and bonded to each other through adhesive properties of the polymer of the outer tube when heated. In some examples, a distal portion of the guidewire support tube can protrude distally beyond the distal end of the inflatable balloon by 2 mm-8 mm. 
     In accordance with some examples, a method can involve passing a perfusion catheter, including a balloon, and an elongate shaft that is attached to the balloon, into a blood vessel until the balloon is positioned adjacent a perforation or dissection in a wall of the blood vessel. The method can also involve inflating the balloon to seal the perforation or dissection in the wall of the blood vessel including urging fluid through a lumen of the elongate shaft and into the balloon to inflate a series of helical windings of the balloon. The balloon, upon inflation, can move from a deflated configuration to an inflated configuration at which an outer surface of the balloon engages the wall of the blood vessel and an inner surface of the balloon&#39;s series of helical windings defines a passage. After inflating the balloon, the method can involve passing a treatment device at least partially through the passage, including receiving, in a distal-to-proximal direction, or delivering, in a proximal-to-distal direction, a treatment device. The method can also involve deflating the balloon by withdrawing fluid from the balloon in a distal-to-proximal direction of the balloon, and retracting the perfusion catheter from the blood vessel. 
     In some examples, passing the perfusion catheter into the blood vessel can include advancing a guidewire through a guidewire support tube, which is separate from the lumen of the elongate shaft and the passage defined by the balloon&#39;s series of helical windings. In some examples, passing the perfusion catheter into the blood vessel can include advancing a guidewire through a guidewire support tube, which is inset into the inner surface of the balloon&#39;s series of helical windings. In some examples, inflating the balloon can include dilating occlusive material accumulation within the wall of the blood vessel. In some examples, inflating the balloon can involve urging the fluid into the balloon in a distal-to-proximal direction of the balloon. In some examples, deflating the balloon and retracting the perfusion catheter can occur simultaneously. In some examples, inflating the balloon can include inflating the balloon to a pressure between 2 atm-20 atm, inclusive. In some examples, delivering the treatment device to the treatment site or distal to the perforation or dissection can include guiding the treatment device along a path offset from an axis of the elongate shaft. In some examples, inflating the balloon can involve urging the fluid through a fluid connection at a distal end of the balloon and a distal end of the elongate shaft. 
     Certain terms are used throughout this patent document to refer to particular features or components. As one skilled in the art appreciates, different people may refer to the same feature or component by different names. This patent document does not intend to distinguish between components or features that differ in name but not in function. 
     For the following defined terms, certain definitions shall be applied unless a different definition is given elsewhere in this patent document. The terms “a,” “an,” and “the” are used to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” The term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B.” All numeric values are assumed to be modified by the term “about,” whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (e.g., having the same function or result). In many instances, the term “about” can include numbers that are rounded to the nearest significant figure. The recitation of numerical ranges by endpoints includes all numbers and sub-ranges within and bounding that range (e.g., 1 to 4 includes 1, 1.5, 1.75, 2, 2.3, 2.6, 2.9, etc. and 1 to 1.5, 1 to 2, 1 to 3, 2 to 3.5, 2 to 4, 3 to 4, etc.). The terms “patient” and “subject” are intended to include mammals, such as for human or veterinary applications. The terms “distal” and “proximal” are used to refer to a position or direction relative to the treating clinician. “Distal” and “distally” refer to a position that is distant from, or in a direction away from, the treating clinician. “Proximal” and “proximally” refer to a position that is near, or in a direction toward, the treating clinician. 
     The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended; that is, a device, kit or method that includes features or components in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. 
     The Abstract is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.