Patent Publication Number: US-2023150852-A1

Title: Method and Devices for Passing a Chronic Total Occlusion and Re-entry into a True Lumen

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention describes devices and methods for passing or crossing Chronic Total Occlusions (CTO). More particularly, the invention describes devices and methods for guidewire re-entry from the subintimal space to the distal true lumen while treating chronic occlusion, and establishing a vehicle for other interventions to follow, and to re-establish blood flow past the CTO. 
     2. Description of the Related Art 
     Age, high cholesterol and other factors are causing arterial atherosclerosis and vascular disease, and can cause vascular occlusions that are frequently called CTO. CTO&#39;s are well-organized tissue that is often calcific, and which completely block blood flow, thereby completely occluding portions of the patient&#39;s vasculature and presenting significant risks to a patient&#39;s health. A coronary artery CTO may result in painful angina, loss of cardiac tissue or patient death. A CTO of the femoral and/or popliteal arteries in the leg may result in limb-threatening ischemic and potential limb amputation. 
     Angioplasty is the most common treatment for CTO, and crossing a CTO is one of the most challenging procedures for interventional clinicians. Recanalizing CTOs can improve exercise capacity, symptoms and possibly reduce mortality. Many strategies such as escalating wire stiffness, parallel wire, see-saw, contralateral injection, subintimal tracking and re-entry (STAR), retrograde wire techniques (controlled antegrade retrograde subintimal tracking—CART), reverse CART, confluent balloon, rendezvous in coronary, and looping wire, among others, have been described in the prior art. 
     Current endovascular devices and techniques frequently fail to cross CTO, often landing a CTO crossing guidewire in a subintimal space with endless efforts to re-cross the CTO into a true lumen. Much time is spent to re-enter into a true lumen with a high risk of perforating a vessel, Consequently, the challenge of crossing a CTO is still incomplete and there is a need for further technical improvements. 
     SUMMARY OF THE INVENTION 
     Methods and devices disclosed herein are suitable as the first-line approach/therapy to cross a CTO by placing a guidewire intentionally in a subintimal space, or for a bailout approach of a failed true-to-true lumen CTO crossing when the guidewire ends in a subintimal space after multiple failed attempts to cross the CTO true-to-true lumen. 
     The present invention describes devices and methods employed to cross a CTO by entering the wall of a vascular lumen for bypassing the CTO, Entry into a vascular wall involves the passage of an endovascular device into and out of the wall which is often described as false lumen access, intramural access, submedial access or otherwise commonly called subintimal space access. 
     A novel CTO passing and re-entry method, and associated devices, are proposed. For coronary CTO passing and re-entry, this can be called antegrade transient fenestration and guidewire re-entry. For passing a CTO in peripheral arteries, this can be called antegrade, retrograde, contralateral or brachial transient fenestration and guidewire re-entry, depending on the specific access approach. 
     Methods of the present invention include creating fenestrations, or the opening of the dissection, or creating flaps between the false and true lumens. This is achieved by advancing a slightly undersized balloon into the subintimal space, and inflating it across the distal cap of the CTO and creating fenestration. After balloon deflation, a soft (slippery) polymer-jacketed guidewire is then advanced across the fenestration created by balloon inflation from the subintimal space into the true lumen. 
     Methods of the present invention can be performed within 30 seconds from the moment when the balloon catheter is deflated in a subintimal space because the fenestration tends to quickly close. The sooner a guidewire slides through the fenestration, the easier it is to place it in the true lumen, preferably within 10 seconds. The fenestration is usually opened the widest in the first few seconds, and tends to close quickly within the next few seconds. 
     Embodiments of the present invention also include a low-profile balloon catheter that is suitable for entering the subintimal space, and then dissecting or opening a fenestration between a subintimal space and a true lumen, and which can be easily removed. Preferably, such balloon catheters should be equipped with three lumens, one lumen for the balloon inflation and deflation and two guidewire lumens, one guidewire lumen for placement of the balloon catheter at the fenestration area, and one guidewire lumen for re-entry in a true lumen. 
     In another embodiment of the present invention, the balloon catheter has at least two guidewire lumens. Each guidewire lumen is preferably a separate guidewire lumen; however, the lengths, distal exits/entry and proximal exits/entry may have different locations. 
     Different locations for the proximal entry of the guidewire lumens also provide a differentiation for the operator where guidewires in these lumens are designated. 
     In another embodiment, the balloon catheter has two balloons and two guidewires with a re-entry guidewire exit located between the balloons. 
     In yet another embodiment, the balloon catheter has a re-entry guidewire exit directly attached to the balloon. 
     The balloon catheter of the present invention provides the benefits of both an over-the-wire balloon catheter and a rapid-exchange balloon catheter. Such unique features allow the balloon catheter to be placed at the treatment location using one guidewire, while another guidewire may be used for clinical procedures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1 A  is a plan view of a balloon catheter with dual guidewire lumens according to the present invention. 
         FIG.  1 B  is a cross-sectional view of the catheter in  FIG.  1 A  showing three lumens. 
         FIG.  10    is a cross-sectional view of the catheter in  FIG.  1 A  showing three lumens according to an alternative embodiment. 
         FIG.  1 D  is a cross-sectional view of alternative embodiment of the catheter of  FIG.  1 A . 
         FIG.  2 A  is a plan view of an alternative balloon catheter according to the present invention having one guidewire lumen utilized for two guidewires. 
         FIG.  2 B  is a cross-sectional view of the catheter taken along line A-A in  FIG.  2 A . 
         FIG.  2 C  is a cross-sectional view of the catheter taken along line B-B in  FIG.  2 A . 
         FIG.  2 D  is a cross-sectional view of the catheter taken along line C-C in  FIG.  2 A . 
         FIG.  2 E  is a cross-sectional view of alternative embodiment of the catheter of  FIG.  2 A  taken along either line A-A or C-C. 
         FIG.  3    is enlarged view of a CTO with a guidewire in a subintimal space. 
         FIG.  4    shows the balloon catheter of  FIG.  1 A  in the subintimal space of FIG. 
         FIG.  5    shows the balloon catheter of  FIG.  4    inflated in the subintimal space of  FIG.  3   . 
         FIG.  6    shows the balloon of  FIG.  5    deflated and a second guidewire advanced from the guidewire lumen through fenestration and into a distal true lumen. 
         FIGS.  7 A,  7 B,  7 C and  7 D  illustrate cross-sectional views of the fenestration between a false lumen and true lumen within 0-30 seconds after balloon deflation. 
         FIG.  8    shows a dual guidewire balloon catheter having one guidewire lumen with an entry port, and an exit port distal to the balloon. 
         FIG.  9    shows a dual guidewire balloon catheter with the first and second guidewire lumens located coaxially within the inner lumen of the catheter shaft. 
         FIG.  10    shows a dual guidewire balloon catheter with an intermediate portion having two guidewire lumens positioned partially in parallel. 
         FIG.  11    shows a dual guidewire balloon catheter having two distal balloons and a re-entry guidewire exit located between the two balloons. 
         FIG.  12    shows an alternative configuration of a balloon catheter shaft that can be used for any of the embodiments herein. 
         FIG.  13    shows a dual guidewire balloon catheter with a re-entry guidewire exit lumen attached to the balloon. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As used herein, “subintimal space” and “re-entry from subintimal space” are related to passing or crossing a chronic total occlusion, and pertains to the area beneath the intima and adventitial layers in a blood vessel. 
     The terms “balloon” and “balloon catheter” refer to the catheter having a balloon. 
     The terms “false lumen” and “subintimal space” refer to the same area and relates to the same tract. 
     The term “rapid exchange fashion” refers to a balloon catheter having a “second” guidewire lumen or rail with the entry at the distal end of the catheter and the exit at any location proximal to the balloon. 
     The term “over-the-wire fashion” refers to a balloon catheter having a “first” guidewire lumen or rail with the entry at the proximal end of the catheter and an exit at the distal portion of the catheter either distally to the balloon, proximally to the balloon or at the distal end of the balloon catheter. 
       FIG.  1 A  shows a balloon catheter  100  having a balloon  101  and a catheter shaft  102 . The catheter shaft  102  has a distal end  103  and a proximal end  104 . The catheter shaft  102  is connected at its proximal end  104  to a Y-connector  105 , which has balloon inflation port  106  and a guidewire port  107 . The catheter shaft  102  has three inner lumens as shown in  FIG.  1 B : a balloon inflation lumen  108 , a first guidewire lumen  109  for placement of an over-the-wire guidewire, and a second guidewire lumen  110  for placement of a rapid-exchange guidewire. 
     The balloon  101  is inflated by infusing saline  111  (or saline in mixture with contrast) via an inflation port  106  and into the inflation lumen  108 . The saline  111  is delivered into the balloon  101  through inflation holes  112 . 
     To assure delivery and infusion of saline  111  inside the balloon  101 , continuity of the inflation lumen  108  is terminated internally before the distal end  103  of the catheter shaft  102 . Terminating the continuity of the inflation lumen  108  may by accomplished by extruding a discontinuity, plugs, glue and other means (not shown). 
     The first guidewire lumen  109  is constructed for over-the-wire use. The entry into the first guidewire lumen  109  is located at the port  107  and the exit  113  is located proximally to the balloon  101 . The guidewire  114  is introduced through the first guidewire lumen  109 . 
     Alternatively, the exit  113  for the first guidewire lumen  109  may be situated at any proximal area from the location of the balloon  101  on the shaft  102 , including the space within the balloon  101  (not shown). The exit  113  may also be located distally from the balloon  101 , as well as at the exit from the distal end  103  of the catheter shaft  102  (not shown). 
     The second guidewire lumen  110  is constructed for rapid-exchange use. The entry  115  into the second guidewire lumen  110  is coaxially located on the distal end  103  of the catheter shaft  102 . The exit for the guidewire from the second guidewire lumen  110  is located at the area  116 . The exit area  116  may be situated at any location along the catheter shaft  102  proximal from the balloon  101  but before reaching the Y-connector  105 . The guidewire  117  is introduced through the second guidewire lumen  110 . 
     The guidewire lumens  109  and  110  may be made within one continuous extrusion and included together with the balloon inflation lumen  108  in the catheter shaft  102  as shown in  FIG.  1 B . Alternatively, separate individual tubes  108 A,  109 B  110 C may be extended coaxially inside the inner lumen  118  of the catheter shaft  102  as shown in  FIG.  10   , The tube  108 A may provide access for balloon inflation and deflation, while the tubes  109 B and  110 C may be provided for guidewire functions. Also, as shown in  FIG.  1 D , the inner lumen  118  of the shaft  102  may be used for delivering inflation medium for balloon inflation and deflation, while the separate tubes  109 A and  110 A may be provided for guidewire function. 
     Several alternative constructions for guidewire lumens are provided regarding locations for the first (over-the-wire) lumen  109  and the second (rapid-exchange) lumen  110 . All these options are well-known in the art and will only be described herein without reference to any drawings. 
     The first guidewire lumen  109  for over-the-wire use may have the guidewire entry port located at the entry  107  as shown in  FIG.  1 A  or anywhere at the proximal end  104  of the catheter shaft  102 . The exit port  113  of the first guidewire lumen  109  may be located proximal to the balloon  101  as shown in the  FIG.  1 A . Also, the exit port  113  of the first guidewire lumen  109  may be located distal to the balloon  101  along the distal end  103  of the balloon catheter shaft  102  (not shown). Alternatively, the exit port  113  of the first guidewire lumen  109  may be located at the very distal end  115  of the catheter shaft  102  (not shown). 
     The second guidewire lumen  110  for rapid-exchange use may have the guidewire entry port at the distal end  103  of catheter shaft  102 , with the exit port located proximal to the balloon  101  or distally to the balloon  101 . 
     Furthermore, the dual lumen balloon catheter may have two guidewire lumens, both constructed for over-the-wire use. In such a case, the first and the second guidewire lumens will have guidewire entry ports at the proximal end of the catheter shaft and the exit ports at the distal end of the catheter shaft (not shown). 
     The dual lumen balloon catheter may also have two guidewire lumens, both constructed for rapid exchange use. In such a case, the first and the second guidewire lumens will have guidewire entry ports at the distal end of the catheter shaft and the exit ports proximal to the balloon (not shown). 
       FIG.  1    shows the balloon catheter  100  with dual guidewires having three lumens, a balloon inflation and deflation lumen  108 , a first guidewire lumen  109 , and a second guidewire lumen  110 . The internal structure of the shaft  102  may include one extrusion with three lumens as shown in  FIG.  1 B , or have separate tubes  108 A,  109 B and  110 C coaxially extending inside the lumen  118  of the shaft  102  as shown in  FIG.  10   , or have two separate lumens  109 A and  110 A inside the inner lumen  118  of the shaft  102 , as shown in  FIG.  1 D . 
     The balloon  101  preferably comprises a non-compliant balloon made of relatively non-elastic material, including but not limited to, medium density polyethylene, linear low-density polyethylene, polyethylene terephthalate, nylon, polyester, or any of a variety of other medical grade polymers known for this use in the medical balloon art. Preferably, the geometry and balloon materials will withstand an internal pressure of at least 8 atmospheres without any leakage or rupture. The fluid to inflate the balloon  101  may be saline, contrast or saline diluted contrast that is introduced at any suitable rate as preferred by the physician. 
     The balloon  101  may be made with reinforcement, implemented cutting edges or other features to improve its ability to create fenestration in the subintimal space, Balloons with such features are well known in the art, including but not limited to: AngioSculpt™ Balloon (Spectranetics Colorado Springs, Colo.), Chocolate™ Balloon (TriReme Fremont, Calif.), and VascuTrack™ (Cardinal Health Dublin, Ohio). 
     Materials used for the catheter and the guidewires are well-known in the art and no additional description will be provided. 
       FIG.  2 A  shows an alternative balloon catheter  200  according to the present invention comprising a balloon  201  and a shaft  202  having the distal end  203  and proximal end  204 . The proximal end of the shaft  204  is attached to a Y-connector  205  having an inflation port  206  and a guidewire port  207 . An irrigation lumen  208  and a guidewire lumen extend longitudinally along the shaft  202 . The balloon  201  is inflated with saline  210  via an inflation port  206  and outlet ports  211  located inside the balloon  201 . The guidewire lumen is divided into two lumen segments, a first over-the-wire lumen segment  209 A and a second rapid-exchange lumen segment  209 B. 
     The second rapid exchange lumen segment  209 B extends through the distal portion  212 , and has an entry port  213  located on the distal end  203  of the shaft  202 , and an exit port  214  located on the shaft  202  proximal to the balloon  201 . A rapid-exchange guidewire  215  is shown extending through the second rapid exchange lumen segment  209 B in the distal portion  212 . 
     The first over-the-wire lumen segment  209 A extends through the proximal portion  216 , and has an entry port  207  and an exit port  217  that are both located proximal to the port  214 . An over-the-wire guidewire  218  is shown extending through the first over-the-wire lumen segment  209 A in the proximal portion  216 . 
     The balloon  201  is inflated by infusing saline  210  (or saline in mixture with contrast) via the inflation port  206  and into the inflation lumen  208 . The saline  210  is delivered into the balloon  201  through inflation holes  211 . 
       FIG.  2 B  shows the cross-section A-A of the shaft  202  with the irrigation lumen  208  and the first over-the-wire lumen segment  209 A along the length of the proximal portion  216 .  FIG.  2 C  shows the cross-section B-B of the shaft  202  between the exit ports  214  and  217 , where there is no guidewire lumen and only the irrigation lumen  208 .  FIG.  2 D  shows the cross-section C-C of the shaft  202  with the irrigation lumen  208  and the second rapid exchange lumen segment  209 B along the length of the distal portion  212 . 
     Thus, the guidewire lumen does not extend within the shaft  202  at the area around the cross-section B-B. This area constitutes an interruption of the guidewire lumen in this area, and may be achieved by extruding a discontinuity, providing plugs, using glue, and other suitable means. 
     Several alternative constructions for guidewire lumens can be provided regarding locations for the exit and the entry of the first over-the-wire lumen segment  209 A and the second rapid-exchange lumen segment  209 B. All these options are known in the art and will only be described herein without reference to any drawings. 
     The first over-the-wire lumen segment  209 A may have the guidewire entry port located at the entry  207  as shown in  FIG.  2 A  or anywhere at the proximal end  204  of the catheter shaft  202 , and the exit port may be located at the exit  217  or anywhere along the catheter shaft  202  proximal to the balloon  201 . 
     The second rapid exchange lumen segment  209 B may have the guidewire entry port at the distal end  213  of catheter shaft  102 , and the exit port  214  located anywhere proximal to the balloon  201 . 
     Alternatively, separate tubes may be used inside the shaft  202 : one tube for inflating and deflating the balloon  201 , one separate tube for the first over-the-wire lumen segment  209 A attached on one end to the exit  217  and on the other end to the entry port  207 , and one separate tube for the second rapid exchange lumen segment  209 B attached on one end at the distal end  103  of the shaft  102  and on the other end attached at the exit  214 . 
     Thus,  FIG.  2    shows the balloon catheter shaft  202  comprising two lumens  208  and  209 A/ 209 B extruded from the body of the catheter shaft  202 . Alternatively, as shown in  FIG.  2 E , the catheter shaft  202  can be provided with an inner lumen  219 , and a separate guidewire tube  209 A/ 209 B may be coaxially extended inside the inner lumen  219 . In this embodiment, the inner lumen  219  functions to deliver inflation medium for balloon inflation and deflation. 
       FIGS.  1 A and  2 A  show several different locations for the guidewire exit ports and entry ports. The entry and exit ports for these guidewire lumens are not limited to locations along the same axial line, as they can be radially offset from each other at any desired angle. 
     The guidewires  114  and  117  in  FIG.  1    and the guidewires  215  and  218  in  FIG.  2    are not limited to any guidewire dimension, length or structure, and can be any conventional guidewire. 
       FIG.  3    shows a blood vessel  300  having a true lumen  301 , and a CTO  302  located inside the vessel  300  having a distal cap  303  and proximal cap  304 . The CTO  302  is inadvertently wired in a subintimal fashion into the subintimal space  305  with the guidewire  306  having a distal end  307 . The distal end  307  of the guidewire  306  is located beyond the distal cap  303  of the CTO  302  and in the subintimal space  305 . 
     The guidewire  306  may be navigated at the beginning of the passing of the CTO  302  in the subintimal space  305  of the vessel  300 . Such a scenario will be considered as an intentional subintimal crossing of CTO  302 . However, most of interventional clinicians will attempt to cross the CTO  302  within the true lumen  101  and through the CTO  302 . After a minute or so of probing the CTO  302  with the guidewire  306 , the clinician will quickly understand the morphology of the CTO  302  and either decide to continue with a different kind of guidewire hoping to cross CTO  302  in the true lumen  301 , or to place the guidewire  306  in the subintimal space  305 . 
     Once the distal end  307  of the guidewire  306  is in the subintimal space  305 , re-entry of the guidewire  306  into the vessel  300  should be attempted as close as possible to the distal cap  303  of the CTO  302 , and far from the beginning of any side branches. This will minimize the risk of damaging any side branches during the guidewire manipulations, and maximize the likelihood of achieving a good distal flow. 
     The subintimal technique creates a neo-lumen between the intimal and adventitial layers of the arterial wall, displacing the atheromatous and calcified intimal and medial layers to the contralateral side of the vessel lumen (not shown) and producing a relatively smooth flow lumen. 
     Subintimal peripheral recanalization and angioplasty of the femoral and popliteal arteries are widely practiced and have diminished reliance upon bypass as first-line therapy. Re-entry into the true lumen is usually the most time-consuming part of interventional procedures. Improved CTO guidewires and support catheters, pedal access, re-entry catheters, and CTO crossing devices have recently been developed that significantly improve true lumen and subintimal crossings. However, as in coronary CTO crossing, re-entry in the femoral and popliteal arteries may be challenging, especially in the presence of calcification. 
     The subintimal space made by a guidewire is a strong factor of unsuccessful recanalization of CTOs. Once the subintimal space is created by a guidewire, the guidewire tends to slip into this space repeatedly and extend it along the circumference of the media of the vessel wall. If this happens, it is difficult to reach the distal true lumen or re-enter into the distal true lumen. 
     The most difficult part of a CTO passing or crossing procedure is to penetrate tissue at the distal end of the CTO to reach the distal true lumen  301 . The major reason is the presence of enlarged false lumens in subintimal space made by a guidewire around the distal true lumen. 
     Re-entry into the true lumen  301  with the guidewire  306  should be performed as close as possible to the distal cap  303  of the CTO  302  and away from the takeoff of side branches so as to minimize the subintimal track and the risk of losing side branches, 
       FIG.  4    shows the dual guidewire balloon catheter  100  of  FIG.  1    introduced over a guidewire  306  located in the second rapid-exchange guidewire lumen  110  into the subintimal space  305 . The balloon  101  is located across of the distal cap  303  of the CTO  302 . The second guidewire  114  is extended through the first over-the-wire guidewire lumen  109  slightly outside of the exit port  113 . 
     The balloon  101  is sized 1:1 or less as compared to the vessel  300  diameter to avoid perforation of the vessel  300  when the balloon  101  is inflated. For example, if the vessel  300  size is 3 mm, the appropriate size of the balloon  101  should be 2.5 mm. Using a nominal balloon inflation pressure with non-compliant balloons would assure that the 1:1 ratio between the balloon size and vessel diameter will never be exceeded. 
       FIG.  5    shows the balloon  101  of the  FIG.  1 A  inflated across the distal cap  303  of the CTO  302  such that inflating the balloon  301  will partially dilate the distal cap  303 . The diameter of the inflated balloon  101  should be equal to or slightly smaller than the size of the vessel  300  to avoid perforations in the vessel  300 . 
     Dilatation of the balloon  101  within the subintimal space  305  over the distal portion  303  of the CTO  302  will squeeze and dilate the area of the distal cap  303  as shown by arrow  500  towards the vessel  300 . Thus, the balloon  101  creates tears, rips, splits, slashes, slits or snags of the dissected portion. Alternatively, the balloon device of  FIG.  2 A  may be used instead of the balloon device  100  of  FIG.  1   . 
       FIG.  6    shows the balloon  101  of  FIG.  5    deflated. After the balloon  101  is deflated, a fenestration  600  between the subintimal space  305  and the true lumen  301  is created with split flaps  601  and  602 . The second guidewire  114  is advanced from the first over-the-wire lumen exit  113  through the fenestration  600  into the distal true lumen  301 . Once the guidewire  114  is positioned in the true lumen  301  of the vessel  300 , a conventional angioplasty (e.g., including but not limited to conventional balloon angioplasty, stenting or the use of drug eluting balloons) will follow. 
     The fact that the balloon  101  is partially positioned on the distal cap  303  of the CTO  302  may be a contributing factor in creating the fenestration  600 . Presence of a harder plaque within the balloon  101  inflation space may serve as a “cutting” element and further facilitate creation of the fenestration  600 . 
     The re-entry guidewire  114  should preferably be a polymer-jacketed, low tip-load guidewire, which can be one of the following: Sion Black™ or Fielder™ family, Asahi Intecc, Nagoya, Japan; or Fighter™, Boston Scientific; for ease and smooth manipulation and advancement. 
     Often, in clinical reality, there is no clear defining line between where the distal cap  303  of the CTO  302  ends and where a healthy vessel begins. Frequently, the presence of plaque or calcification appears in the vessel  300  distal to the distal cap  303  of the CTO  302 . In such a circumstance, harder plaque or calcification can help to create a fenestration when there is a need to dilate the balloon again and create another fenestration. 
     The orientation of the guidewire exit port  113  of the catheter shaft  102  within the subintimal space  305  should preferably be directed towards the true lumen  301  during inflation and deflation of the balloon  101 , Use of a directional L-shape radiopaque marker at the exit port  113  location may be helpful to direct the guidewire  114  into the true lumen  301  (not shown). 
     Once the guidewire  114  is advanced into the true lumen  301 , a conventional angioplasty can follow that may include, but is not limited to, deployment of a drug eluting stent or drug eluting balloon. More detailed illustrations showing fenestration between the subintimal space  305  and the true lumen  101  are shown in  FIGS.  7 A,  7 B,  7 C,  7 D . 
     When the balloon  101  is deflated, the guidewire  114  must be manipulated quickly to smoothly pass through the fenestration  600  from the subintimal space  305  and into the true lumen  301 . Multiple approaches may be required to pass the second guidewire  114  from the subintimal space  305  into the true lumen  301 . If the clinician has trouble to re-enter the guidewire  114  into the true lumen  301 , the process of dilating the balloon  101  to create another fenestration  600  may be repeated again at a more distal location. 
       FIG.  7 A  illustrates a cross-sectional view based on a schematic Intravascular Optical Coherence Tomography (OCT) picture inside the vessel  300  and after the balloon  101  has been deflated and removed. The fenestration  600  between the false lumen or subintimal space  305  is opened to its widest extent. The dissection flaps  601  and  602  created during the balloon  101  inflation as shown in  FIG.  5    expose a wide aperture from the subintimal space  305  into the true lumen  301 . OCT analyses indicate that such wide fenestration will stay open approximately 3-4 seconds, 
       FIG.  7 B  illustrates the same area as in  FIG.  7 A  at a timing of 4-5 seconds from the balloon  101  deflation. The fenestration  700  is becoming smaller than the fenestration  600  shown in  FIG.  6 A , 
       FIG.  7 C  illustrates the same area as in  FIGS.  7 A &amp;  7 B  at a timing of 10 seconds after the balloon  101  deflation. The fenestration  701  is further narrowing and the dissection flaps  601  and  602  are getting close to each other. Thus, this indicates that the fenestrations  600 ,  700  and  701  between the subintimal space  305  and the true lumen  301  after the balloon  101  deflation are transient in the nature. 
       FIG.  7 D  illustrates the same area as in  FIGS.  7 A,  7 B &amp;  7 C  at a timing of 30 seconds after the balloon  101  deflation. The fenestration  702  has disappeared and the dissection flaps  601  and  602  are almost closed. This further validates the fact that the fenestration  600  between the subintimal space  305  and the true lumen  301  after the balloon  101  deflation will narrow after 10 seconds, and be almost closed after 30 seconds. The opportunity to sneak the re-entry guidewire  114  from the subintimal space  305  into the true lumen  301  will diminish after 30 seconds from balloon  101  deflation. 
     Frequently, multiple approaches are required to slide the re-entry guidewire  114  through the fenestration  600  to pass the re-entry guidewire  114  into the true lumen  301 . If the passing of the re-entry guidewire  114  is not successful within the 30 seconds from the time when the first fenestration was created, it would be desirable to dilate the balloon  101  again and create another fenestration, preferably at slightly more distal location. 
     Crossing of the CTO and re-entry approaches described in the present invention carry the risk of arterial perforations. While perforations in peripheral arteries are less dangerous, perforations in coronary arteries may cause cardiac tamponade that constitutes the most severe clinical consequence. In the case of perforations, the balloon devices of the present invention may provide at least a temporary vehicle to stop bleeding and provide time for the clinician to proceed with other procedural steps, if needed, including cover stent placement or micro-coils deployment if the perforation is located in the distal portion of the vessel and it is not possible to heal with prolonged temporary balloon closure. 
     The balloon catheter  800  in  FIG.  8    comprises a balloon  801  and an extrusion shaft  802  having a distal portion  803  and a proximal portion  804 . A first over-the-wire guidewire lumen  805  extends along the proximal portion  804  of the shaft  802  and has an exit port  806  located proximal to the balloon  801 . A second rapid-exchange lumen  807  extends along the distal portion  803  of the shaft  802  located distal to the balloon  801  and has an entry port  808  located on the very distal end of the shaft  802  and an exit port  809  located distal to the balloon  801 . The balloon  801  is inflated using a lumen  810  within the shaft  802  having inflation exit ports  811  inside the balloon  801 . A guidewire  813  is extended through the over-the-wire lumen  805 , and a guidewire  814  is extended through the rapid-exchange lumen  807   
     The guidewire  814  is extended around the balloon  801  and may be utilized as a cutting edge to improve the ability of the balloon  801  to create fenestrations in the subintimal space. Alternatively, other balloons having any form of cutting edges may improve the ability to create fenestrations in the subintimal space. Balloons with such features may include but are not limited to: AngioSculpt™ Balloon (Spectranetics Colorado Springs, Colo.), Chocolate™ Balloon (TriReme Fremont, Calif.), and VascuTrack™ (Cardinal Health Dublin, Ohio) 
     The balloon catheter  900  of  FIG.  9    comprises a balloon  901 , a shaft  902 , a distal portion  903  and a proximal portion  904 . A first over-the-wire guidewire lumen  905  extends along the proximal portion  904  of the shaft  902  and has an exit port  906  located proximal to the balloon  901 . A second rapid-exchange lumen  907  extends along the distal portion  903  of the shaft  902  and has an entry port  908  located on the very distal end of the shaft  902  and an exit port  909  located proximal to the balloon  901 . The over-the-wire guidewire lumen  905  is located coaxially within the shaft  902  within its proximal portion  905 . The rapid-exchange guidewire lumen  907  is located coaxially within the catheter shaft  902  on its distal portion  903 . A guidewire  910  is extended through the over-the-wire lumen  905 , and a guidewire  911  is extended through the rapid-exchange lumen  907 . 
     An intermediate space is defined between the exit port  906  of the over-the-wire lumen  905  and exit port  909  of the rapid-exchange lumen  907 , where there is no guidewire lumen. 
     The balloon catheter  1000  of  FIG.  10    comprises a balloon  1001 , a shaft  1002 , a distal portion  1003 , and a proximal portion  1004 . A first over-the-wire guidewire lumen  1005  extends along the proximal portion  1004  of the shaft  1002  and has an exit port  1006  located proximal to the balloon  1001 . A second rapid-exchange lumen  1007  extends along the distal portion  1003  of the shaft  1002  and has an entry port  1008  located on the very distal end of the shaft  1002  and an exit port  1009  located proximally to the balloon  1001 . The exit port  1009  of the rapid-exchange guidewire lumen  1007  is located proximal to the exit  1006  of the over-the-wire lumen  1005 . A guidewire  1010  is extended through the over-the-wire lumen  1005 , and a guidewire  1011  is extended through the rapid-exchange lumen  1007 . The inner lumen defined by the shaft  1002  provides for inflation of the balloon  1001 . 
     The proximal end  1012  of the rapid-exchange lumen  1007  and the distal end  1013  of the over-the-wire lumen  1005  are positioned in parallel in an overlapping manner inside the lumen the shaft  1002  and within an intermediate area  1014 . Such intermediate area  1014  may have a length between 1 mm to 150 cm, preferably 5-20 cm. 
       FIG.  11    shows a balloon catheter  1100  comprising a distal balloon  1101  and a proximal balloon  1102 , Both balloons  1101  and  1102  are located on the distal portion of an elongated shaft  1103 . The distal balloon  1101  and the proximal balloon  1102  are fluidly connected with the inner lumen defined by the shaft  1103 . The distal balloon  1101  and the proximal balloon  1102  may be inflated using contrast, or a mixture of contrast with saline solution, as shown by arrow  1104 . A first lumen  1105  extends from the proximal end of the balloon catheter  1100  and exits between distal balloon  1101  and proximal balloon  1102  at the exit port  1106 . The first lumen  1105  serves to accommodate a first guidewire  1107  in a conventional over-the-wire fashion. A second lumen  1108  extends from the very distal end  1109  of the balloon catheter  1100  and exits proximal to the proximal balloon  1102  at the exit port  1110 . The second lumen  1108  serves to accommodate a second guidewire  1111  in a conventional rapid-exchange fashion. The first lumen  1105  and the second lumen  1108  may be in a parallel, overlapping relationship with each other for a portion of their lengths, or may be coaxially extended inside the shaft  1103  in a similar manner as the lumen  905  and  907  shown in  FIG.  9   . 
     The catheter shaft  1103  may be made from a multi-lumen extrusion and provide the same guidewire lumen functions as the separate lumens  1105  and  1108  positioned inside the shaft  1103 . 
       FIG.  12    shows a partial view of an alternative configuration for a balloon catheter shaft  1200  comprising lumens  1201 ,  1202  and  1203  attached together or bundled together. Bundling of the lumens  1201 ,  1202  and  1203  may be achieved by any suitable methods, including but not limited to, gluing or fusing (not shown), and such separate lumens may be used for balloon inflation and guidewire functions as desired. In the configuration shown in  FIG.  12   , the lumen  1201  can be used for inflation, the lumen  1202  can be used to accommodate a first guidewire, and the lumen  1203  can be used to accommodate a second guidewire. 
       FIG.  13    shows a balloon catheter  1300  comprising a distal balloon  1301  located on the distal portion of an elongated shaft  1302  which is fluidly connected with the balloon  1301  for balloon inflation. The distal balloon  1301  may be inflated using contrast, or a mixture of contrast with saline solution, as shown by arrow  1303 . A first lumen  1304  extends from the proximal end of the balloon catheter  1300  and exits inside the balloon  1301  at the exit port  1305 . The distal end of the first lumen  1304  is attached to a wall of the balloon  1301  by any suitable method, including but not limited to bonding or fusing. The first lumen  1304  serves to accommodate a first guidewire  1306  in a conventional over-the-wire fashion. A second lumen  1307  extends from the very distal end  1308  of the balloon catheter  1300  and exits proximal to the balloon  1301  at an exit port  1309 . The second lumen  1307  serves to accommodate a second guidewire  1310  in a conventional rapid-exchange fashion. 
     Some clinical, theoretical and hypothetical considerations have been introduced herein for explanation of how devices and methods of the present invention work and are effective; these considerations have been presented for providing a better understanding of the invention only, and do not limit the scope of the claims. 
     The above described embodiments of the invention are merely descriptive of its principles and are not to be considered limiting. Further modifications of the disclosed invention will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the invention as defined by the following claims.