Abstract:
A reperfusion system and method of perfusing a blood vessel using the reperfusion system are provided. A sheath has a sheath wall and a lumen that each extend to a distal end to define a distal opening. A distal portion of the sheath wall has at least one wall opening. A balloon catheter has a lumen that extends to the distal end to define a distal opening. The balloon catheter has an inflatable balloon attached to a distal portion. A conduit has a first end in fluid communication with the lumen of the sheath and a second end in fluid communication with the lumen of the balloon catheter. The reperfusion system is configured to allow blood to enter each of the distal opening and the at least one wall opening of the sheath, flow through the sheath, the conduit, and the balloon catheter, and exit through the distal opening of the balloon catheter. The sheath is introduced into body tissue. The balloon catheter is advanced through the sheath to the blood vessel. The balloon is inflated. Blood is allowed to enter each of the distal opening and the at least one wall opening of the sheath, flow through the sheath, the conduit, and the balloon catheter, and exit through the distal opening of the balloon catheter.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/692,012, filed on Aug. 22, 2012, entitled “INTRODUCER SHEATH FOR PERFUSION REGULATION SYSTEM,” the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present disclosure generally relates to medical devices. More specifically, the present disclosure relates to perfusion regulation systems. 
       BACKGROUND 
       [0003]    In standard catheter embolization procedures, backflow may cause non-target embolization. This backflow may be caused by inadequate techniques employed by the person performing the treatment. Also, where pressure builds up distally such as with embolization procedures with microparticles and liquid embolic agents (glue/Onyx [Ev3]) backflow may result. This backflow may also result in non-target embolization. In order to prevent backflow, an occlusion balloon catheter may be used in the target vessel. However, inflation of the balloon stops the blood flow to the organs and or tissues of the target vessel which introduces additional risks. 
       SUMMARY 
       [0004]    In overcoming the drawbacks and other limitations of the related art, the present disclosure provides artificial antegrade flow in the target vessel. The flow provides perfusion to the tissue and organs and is used to aid the embolic agent in reaching the target area. The present disclosure simultaneously combines no back flow when the balloon is insufflated, full embolization control, and enhanced safety. Once the artificial antegrade blood vessel flow is established, a micro catheter may be introduced through the occlusion balloon catheter, in a coaxial manner, up to the target blood vessel and embolization using standard techniques may be performed. The flow into the introducer sheath is enhanced by including openings on the introducer sheath, for example at the distal portion of the introducer sheath. 
         [0005]    The present disclosure provides a reperfusion system. A sheath has a sheath wall that extends from a proximal portion to a distal portion that has a distal end. The sheath has a lumen that extends to the distal end to define a distal opening of the sheath. The distal portion of the sheath wall having a plurality of wall openings that are one of circumferentially and longitudinally spaced apart. A catheter has a catheter wall that extends from a proximal portion to a distal portion that has a distal end. The catheter has a lumen that extends to the distal end to define a distal opening of the catheter. The catheter is disposed in the lumen of the sheath. The catheter has an expandable member attached to the distal portion. A conduit has a first end in fluid communication with the lumen of the sheath between the sheath wall and the catheter wall, and a second end in fluid communication with the lumen of the catheter. The reperfusion system is configured to allow blood to enter each of the distal opening and the at least one wall opening of the sheath, flow through the sheath, the conduit, and the catheter, and exit through the distal opening of the catheter. 
         [0006]    The present disclosure also provides a method of perfusing a blood vessel. The method includes providing the reperfusion system. The method further includes introducing the sheath in body tissue. The method further includes advancing the catheter through the sheath to the blood vessel. The method further includes expanding the expandable member to prevent blood from flowing in the blood vessel. The method further includes allowing the blood to enter each of the distal opening and the at least one wall opening of the sheath, flow through the sheath, the conduit, and the catheter, and exit through the distal opening of the catheter. 
         [0007]    Further features and advantages of the present disclosure will become apparent from consideration of the following description and the appended claims when taken in connection with the accompanying drawings. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a side schematic view of a reperfusion system; 
           [0009]      FIG. 2  is a cross-sectional view taken along lines  2 - 2  of  FIG. 1 ; 
           [0010]      FIG. 3  is a cross-sectional view taken along lines  3 - 3  of  FIG. 1 ; 
           [0011]      FIG. 4  is a side schematic view of an introducer sheath; 
           [0012]      FIG. 5  is a side schematic view of another introducer sheath; 
           [0013]      FIG. 6  is a side schematic view of another introducer sheath; and 
           [0014]      FIG. 7  is a side schematic view of another introducer sheath. 
       
    
    
       [0015]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
       DETAILED DESCRIPTION 
       [0016]    The present disclosure generally relates to a reperfusion system having an introducer sheath which has openings at its distal portion to optimize blood flow into the introducer sheath and through the reperfusion system. The reperfusion system can be used in all types of embolization procedures including, but not limited to, chemo-embolization, radio-embolization, embolization of high flow blood vessels, situations where there is a high risk of non-target embolization, apparently safe situations in which a non-target embolization might lead to severe complications, and interventional oncology procedures where microparticles (a type of embolic agent) with chemotherapy or with radiation are injected into tumor vessels. 
         [0017]    The term “substantially” used herein with reference to a shape includes variations in the recited shape that are equivalent to the shape for an intended purpose or function. 
         [0018]      FIGS. 1-3  illustrate a reperfusion catheter system  10  which includes an introducer sheath  13  having a sheath wall  17  that extends from a proximal portion  15  to a distal portion  18  that has a distal end  14 . The sheath wall  17  has an inner surface  11  and an outer surface  12 . The inner surface  11  of the sheath wall  17  defines a longitudinal lumen  20  that extends to the distal end  14  to define a distal opening  23  of the introducer sheath  13 . The distal portion has wall openings  29  (i.e. holes or perforations), which will be described in more detail in  FIGS. 4-8 . 
         [0019]    The introducer sheath  13  may be made of polytetrafluoroethylene (PTFE), radiopaque fluorinated ethylene propylene (FEP), or combinations thereof, for example. The introducer sheath  13  may have any suitable size, for example about 5 French, about 8 French, or between about 5 French and about 8 French. The introducer sheath  13  may have an inner diameter  22  of about 0.047 inches and an outer diameter of about 0.094 inches, or it may have an inner diameter  22  of about 0.113 inches and an outer diameter of about 0.133 inches. Thus, the inner diameter  22  may be between about 0.074 inches and about 0.113 inches, and the outer diameter  28  may be between about 0.094 inches and about 0.133 inches, for example. The introducer sheath  13  may be shorter in length than a typical introducer sheath in order to maximize the artificial antegrade blood flow as described in greater detail below. The introducer sheath  13  has the largest inner diameter  22  possible in order to allow antegrade blood flow around an occlusion catheter  25  (e.g. occlusion balloon catheter) that is inserted through the opening  20  in the introducer sheath  13 . The outer diameter  28  of the introducer sheath  13  is as small as possible in order to have a low profile and to minimize puncture site complications. The proximal portion  15  is attached to a lateral check flow  16  which includes a stopcock  19 . The lateral check flow  16  is a side port that may be integrally formed with or attached to the introducer sheath  13 . 
         [0020]    The flexible occlusion balloon catheter  25  has a catheter wall  24  that extends from a proximal portion  27  to a distal portion  40  having a distal end  26 . The catheter wall  24  has an inner surface  45  and an outer surface  42 . The catheter  25  includes a longitudinal lumen  41  that extends to the distal end  26  to define a distal opening  47  of the balloon catheter  25 . 
         [0021]    The balloon catheter  25 , including the catheter wall  24 , may be made of radiopaque vinyl (e.g. polyvinyl chloride), nylon, urethane, or combinations thereof, for example. The balloon catheter  25  may have any suitable size, for example about 5.3 French, or between about 3 French and about 5.3 French. The balloon catheter  25  may have an inner diameter of about 0.038 inches and an outer diameter of about 0.072 inches, or it may have an outer diameter of about 0.039 inches. Thus, the inner diameter may be equal to or less than about 0.038 inches, and the outer diameter may be between about 0.039 inches and about 0.072 inches. 
         [0022]    A detachable valve system  31  (for example, a Touhy-Borst adapter) is attached to a hub  34  in the proximal portion  27  of the balloon catheter  25 . An expandable member  37  (for example, an inflatable balloon) is attached to the distal portion  40  of the balloon catheter  25 . The balloon  37  may be made of polyurethane, nylon, or latex, for example. A side port  43  intersects with the balloon catheter  25  at the proximal portion  27 . The inner surface  45  of the catheter wall  24  defines an inflation lumen  48  that extends from the intersection to the inside of the balloon  37 . The lumen  41  is coaxially located inside the inflation lumen  48 . A wall  50  separates the inflation lumen  41  and the lumen  48 . In other embodiments, the inflation lumen  48  may be located coaxially inside the lumen  41 . In other embodiments, rather than being coaxial, the lumen  41  and the inflation lumen  48  may be non-coaxially spaced away from each other inside the catheter  25 . The balloon  37  can be expanded (e.g. inflated) by providing fluid through the side port  43  and through the inflation lumen  48 . The valve system  31  has a side port  44  which is attached to a connecting tube  46  that extends to and is attached to the lateral check flow  16  of the introducer sheath  13 . Thus, the side port  44 , connecting tube  46 , and the lateral check flow  16  form a conduit that allows blood to flow from the introducer sheath  13  (which, for example, may be located in the lumen of the femoral artery) through the connecting tube  46  into the balloon catheter  25  and exiting through the distal opening  47  of the balloon catheter  25  at the target vessel location. 
         [0023]    A micro catheter  49  may be inserted through the lumen  41  in the occlusion balloon catheter  25  to allow embolization with microparticles, micro coils or liquid embolic agents (glue or Onyx [Ev3]). The micro catheter  49 , including its outer wall  55 , may be made of PTFE, metal braids, nylon, PEBAX, or combinations thereof, for example. The micro catheter  49  may have any suitable size, for example about 2.3 French, or equal to or less than about 2.3 French. The outer diameter  52  of the micro catheter  49  may be about 0.03 inches, or equal to or less than about 0.03 inches. The outer diameter  52  ( FIG. 3 ) is preferably minimized. Also, the outer wall  55  ( FIG. 3 ) of the micro catheter  49  is preferably made as thin as possible as long as there is no compromise in push ability and the ability to deliver embolic agents. Alternatively, embolic agents, for example 0.035″ coils, can be delivered through the occlusion balloon catheter  25 . The catheter system  10  of the present invention is preferably comprised of polymers that provide the specific features of diameter compatibility, flexibility, torque-ability, and optimized blood flow. 
         [0024]      FIGS. 4-7  illustrate introducer sheaths  13 ,  113 ,  213 ,  313 , each having different patterns of openings  29 ,  129 ,  229 ,  329  on the sheath wall  17 , and each of which can be used with the reperfusion system  10 . Each of the openings  29 ,  129 ,  229 ,  329  extend from the inner surface  11  to the outer surface  12  of the introducer sheaths  13 ,  113 ,  213 ,  313 . The patterns and shapes of the openings may be designed to optimize blood flow into the introducer sheath  13 ,  113 ,  213 ,  313  and through the reperfusion system  10 . The  FIG. 4  shows rectangular openings  29  which are circumferentially spaced apart around the entire circumference of the introducer sheath  13 .  FIG. 5  shows circular openings  129 , two of which are longitudinally spaced apart on the introducer sheath  113 . The circular openings  129  may also be circumferentially spaced apart the entire circumference of the introducer sheath  113 . Additionally, as shown in  FIGS. 4 and 5 , the openings  29 ,  129  are formed only on the distal portion  18  of the introducer sheath  13 ,  113 . In variations of the patterns of  FIGS. 4 and 5 , the openings  29 ,  129  may be spaced around only part of the circumference rather than the entire circumference. In variations of the introducer sheaths  13 ,  113  of  FIGS. 4 and 5 , the introducer sheaths  213 ,  313  show the openings  229 ,  329  spaced longitudinally along the entire length of the introducer sheaths  213 ,  313 . Additionally, the openings  229 ,  329  may be circumferentially spaced apart around a part of or the entire circumference of the introducer sheaths  213 ,  313 . In some embodiments, the openings  29 ,  129 ,  229 ,  329  may be located only on the proximal portion  13  of the sheaths  13 ,  113 ,  213 ,  313 . 
         [0025]    The shape of each opening may be a polygon or substantially a polygon, triangle or substantially a triangle, quadrilateral or substantially a quadrilateral, square or substantially a square, rectangle or substantially a rectangle, pentagon or substantially a pentagon, a hexagon or substantially a hexagon, an octagon or substantially an octagon, a circle or substantially a circle, an oval or substantially an oval, or an irregular shape. In some examples, a particular introducer sheath may openings of more than one shape, where the possible combinations may include any of the above shapes. 
         [0026]    In operation the system is used as follows. Once vascular access has been obtained (either arterial/venous), the introducer sheath  13  is introduced into body tissue, for example a blood vessel such as the femoral artery. In the lumen of the blood vessel (e.g. the femoral artery) where the introducer sheath  13  is introduced, the normal blood flow is in the direction of arrow  58 , for example if arterial entry of the introducer sheath  13  is done in the superior direction. Using standard catheterization techniques, the expandable member  25  (e.g. occlusion balloon catheter  25 ) is advanced selectively up to a target vessel. At the lumen of the target vessel, the normal blood flow is in the direction of arrow  61 . The blood flow may be in the direction of arrow  61  in both the vessel where the introducer sheath  13  is introduced, and in the target vessel, for example if arterial entry of the introducer sheath  13  is done in the inferior direction. In such examples, these entry vessel and target vessel may also, for example, be the same vessel. 
         [0027]    The distance between the position where vascular access is obtained (e.g., the femoral artery) and the target vessel varies depending on the location of the target vessel. Accordingly, the length  79  of the balloon catheter  25  between the distal end  14  of the introducer sheath  13  and the balloon  37  will vary depending on how far the balloon catheter  25  is extended into the vasculature. Once the balloon catheter  25  is deployed to the target vessel, the lateral check flow  16  of the introducer sheath  13  may be connected into the valve system  31  (for example, a Tuohy-Borst adaptor) by means of the connecting tube  46 . An adapter such as, for example, a Luer-lock attaches the valve system  31  to the hub  34  of the occlusion balloon catheter  25 . At this point, to stop the blood flow in the target vessel, the expandable member  37  (e.g. balloon  37 ) is expanded (e.g. insufflated, and thereby inflated) by providing fluid through the side port  43  and the inflation lumen  48 . The stopcock  19  can be switched from a closed position to an open position to allow blood from the common femoral artery to flow through the lateral check flow  16  and the valve system and through the reperfusion system  10  into the target vessel. 
         [0028]    The above-identified technique provides an artificial/diverted antegrade flow towards the target vessel that is important to aid the embolic agent in reaching the target area distally, such as for treating a tumor microvasculature. Without having back blood flow in the target vessel when the balloon  37  of the occlusion balloon catheter  25  is insufflated, there is a remarkable enhancement in procedure safety (antegrade flow, no back flow). 
         [0029]    The flow path for the blood is indicated by arrows numbered  1 - 6  in  FIG. 1 . As indicated by arrow  1 , the blood flows into the distal opening  23  and the wall openings  29  of the introducer sheath  13  and flows through the lumen  20  between the outer surface  42  of the balloon catheter  25  and the inner surface  17  of the introducer sheath  13 . The openings  29  are advantageous because they can improve flow into the introducer sheath  13 , especially when there is little room for blood to flow into only the distal opening  23 . From the inside of the introducer sheath  13 , the blood flows into the lateral check flow  16  to the stopcock  19  as indicated by arrows  2 . The blood cannot flow through the introducer sheath  13  past the lateral check flow  16  because the proximal end  60  is sealed. As indicated by arrows  3 , after the blood exits the lateral check flow  16  it passes through the connecting tube  46  to the valve assembly  31 . The blood passes through the valve assembly  31  into the balloon catheter  25  as indicated by arrows  4 . The blood then travels through the balloon catheter  25  (e.g. through the lumen  41 ) as indicated by arrows  5  and exits at the tip  40  of the balloon catheter  25  as indicated by arrows  6 . 
         [0030]    Once the artificial antegrade blood vessel flow is established, a micro catheter  49  may be introduced through the occlusion balloon catheter  25  in a coaxial manner up to the target blood vessel and embolization using standard techniques can be performed. In a high flow blood vessel, the balloon insufflation permits flow control. As there is no retrograde or backflow, there is full control to avoid non-target embolization that may potentially happen at any time during the current embolization techniques using the existing devices available in the market. The balloon  37  may be deflated at any time if needed, and the inherent/native antegrade blood vessel flow can be reestablished immediately. 
         [0031]    As a person skilled in the art will readily appreciate, the above description is meant as an illustration of implementation of the principles of this invention. This description is not intended to limit the scope or application of this invention in that the invention is susceptible to modification, variation and change, without departing from the spirit of this invention, as defined in the following claims.