Patent Publication Number: US-2020289129-A1

Title: Tissue compression device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims under 35 U.S.C. § 119(e) the benefit of the filing date of U.S. Provisional Application No. 62/818,530, filed Mar. 14, 2019, the entire contents of which are incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to tissue compression devices. 
     BACKGROUND 
     A medical catheter may be advanced through an access site into vasculature of a patient to provide a lumen through which a medical device or a therapeutic agent may be introduced to reach a treatment site. For example, the access site for percutaneous coronary procedures may include the radial artery or the femoral artery of a patient. 
     SUMMARY 
     The present disclosure describes tissue compression devices and techniques to apply pressure to an ulnar region (e.g., and not a radial region), a radial region (e.g., and not an ulnar region), or both the ulnar and radial regions of a patient before, during, and/or after a transradial access procedure. The ulnar region may include tissue at or near (e.g., superficial to) an ulnar artery and/or ulnar veins in an arm of the patient. The radial region may include tissue at or near (e.g., superficial to) a radial artery and/or radial veins in an arm of the patient. Application of pressure at the ulnar region may be used to facilitate transradial access, reduce occlusion of the radial artery after transradial procedure, or both. Application of pressure at the radial region may be used to facilitate transradial access, achieve patent hemostasis of the access site of the radial artery after transradial procedure, or both. 
     In some examples, the tissue compression device is non-circumferential, which enables it to apply pressure to less than the entire outer perimeter of a wrist of a patient at a particular time. In this way, the tissue compression device may be configured to more selectively (e.g., more directly) apply pressure to only one of the ulnar region or the radial region at a time. In some examples, a non-circumferential tissue compression device includes a base configured to, when on a wrist of a patient, surround at least a portion of the wrist in a non-circumferential configuration, and an expandable member coupled to the base. The non-circumferential configuration may include a “C” shape configured to allow a clinician to fit the tissue compression device onto the wrist of the patient, orient the tissue compression device to engage the wrist of the patient, and to enable the expandable member to be inflated without becoming disengaged with the wrist of the patient. The expandable member is configured to be positioned over an ulnar region or a radial region of the patient when the wrist is engaged. The expandable member also is configured to apply pressure to the ulnar region or radial region before, during, and/or after a transradial access procedure. 
     In some examples, a tissue compression device may include a base configured to, when on a wrist of a patient, surround at least a portion of the wrist in a non-circumferential configuration, and an expandable member mechanically connected to the base. The expandable member is configured to be positioned over an ulnar region or a radial region of the wrist of the patient when the base is engaged with the portion of the wrist. The expandable member also is configured to apply pressure to the ulnar region or the radial region. 
     In some aspects of the tissue compression device, the expandable member comprises a bladder configured to inflate to at least a pressure to cause compression of tissue near at least one of an ulnar artery or a radial artery of the patient. 
     In some aspects the tissue compression device, when on the wrist of the patient, the tissue compression device is configured to partially surround the wrist in a first orientation and in a second, different orientation, and, when in the first orientation, the expandable member is positioned over the ulnar region, and, when in the second orientation, the expandable member is positioned over the radial region. 
     In some aspects the tissue compression device, when the base is on the wrist of the patient, the expandable member is configured to more directly apply pressure to the ulnar region than the radial region. 
     In some aspects of the tissue compression device, when the base is on the wrist of the patient, the expandable member is configured to more directly apply pressure to the radial region than the ulnar region. 
     In some aspects of the tissue compression device, the base comprises a first curved section extending from a terminal end to a medial end, wherein the first curved section is configured to traverse one of a radial side of the wrist or an ulnar side of the wrist when the base is on the wrist, a second curved section extending from a terminal end to a medial end, wherein the second curved section is configured to traverse the other of the radial side of the wrist or the ulnar side of the wrist when the base is on the wrist, and a substantially straight section extending between the medial end of the first curved section and the medial end of the second curved section. In some aspects of the tissue compression device, the substantially straight section is configured to traverse a dorsal surface of the wrist when the base is on the wrist. In some aspects of the tissue compression device, the first curved section is configured to extend from the dorsal surface of the wrist to a palmar surface of the wrist when the base is on the wrist. In some aspects of the tissue compression device, the second curved section extends from the dorsal surface of the wrist to traverse at least a portion of one of a radial border of the wrist or an ulnar border of the wrist when the base is on the wrist. In some aspects of the tissue compression device, the terminal end of the first curved section and the terminal end of the second curved section define a gap, wherein the gap is sized to enable the wrist of the patient to pass through the gap. 
     In some aspects of the tissue compression device, the base is configured to engage a left wrist of the patient, a right wrist of the patient, or both the left wrist and the right wrist of the patient. 
     In some aspects of the tissue compression, the expandable member is adjustably mechanically connected to the base. 
     In some aspects of the tissue compression device, the expandable member comprises a protrusion extending from a surface of the expandable member and configured to apply pressure to a tissue near an ulnar artery or a radial artery of the patient. 
     In some aspects of the tissue compression device, the expandable member is a first expandable member configured to be positioned over the ulnar region of the wrist of the patient when the base surrounds the portion of the wrist and apply pressure to the ulnar region, wherein the tissue compression device further comprises a second expandable member mechanically connected to the base, wherein the second expandable member is configured to be positioned over the radial region of the wrist of the patient and apply pressure to the radial region when the base surrounds the portion of the wrist. In some aspects of the tissue compression device, the first expandable member comprises a first bladder configured to inflate to at least a pressure to cause compression of tissue near an ulnar artery of the patient, and the second expandable member comprises a second bladder configured to inflate to at least a pressure to cause patent hemostasis of a vascular access site at the radial artery of the patient. In some aspects of the tissue compression device, the second expandable member comprises a bladder configured to inflate to at least a pressure to urge the wrist of the patient toward the first expandable member. 
     In some aspects of the tissue compression device, the base comprises a substantially rigid thermoplastic or a substantially rigid thermoset plastic. 
     In some examples, a tissue compression device may include a non-circumferential base configured to, when on a wrist of a patient, surround only a portion of an outer perimeter of the wrist, and an expandable member mechanically connected to the base. The expandable member is configured to be positioned over an ulnar region or a radial region of the wrist of the patient when the base is on the wrist. The expandable member also is configured to apply pressure to the ulnar region or the radial region. 
     In some aspects of the tissue compression device, when the base is on the wrist of the patient, the expandable member is configured to more directly apply pressure to the ulnar region than the radial region. In some aspects of the tissue compression device, when the base is on the wrist of the patient, the expandable member is configured to more directly apply pressure to the radial region than the ulnar region. 
     In some aspects of the tissue compression device, the base comprises a first section extending from a terminal end to a medial end, wherein the first section is configured to traverse one of a radial side of the wrist or an ulnar side of the wrist when the base is on the wrist, a second section extending from a terminal end to a medial end, wherein the second section is configured to traverse the other of the radial side of the wrist or the ulnar side of the wrist when the base is on the wrist, and a third section extending between the medial end of the first section and the medial end of the second section, wherein the terminal end of the first section and the terminal end of the second section define a gap, wherein the gap is sized to enable the wrist of the patient to pass through the gap. 
     In some aspects of the tissue compression device, the terminal end of the first curved section and the terminal end of the second curved section define a gap, wherein the gap is sized to enable the wrist of the patient to pass through the gap. 
     In some aspects of the tissue compression device, the expandable member comprises a protrusion extending from the surface of the expandable member and configured to apply pressure to a tissue near an ulnar artery or a radial artery of the patient. 
     In some aspects of the tissue compression device, the expandable member is a first expandable member configured to be positioned over the ulnar region of the wrist of the patient when the base is on the wrist and apply pressure to the ulnar region, wherein the tissue compression device further comprises a second expandable member mechanically connected to the base, wherein the second expandable member is configured to be positioned over the radial region of the wrist of the patient when the base is on the wrist and apply pressure to the radial region. 
     In some examples, a method of using a tissue compression device may include positioning the tissue compression device on a wrist of a patient such that a base of the tissue compression device surrounds at least a portion of an outer perimeter of the wrist in a non-circumferential manner, and such that an expandable member mechanically connected to the base is positioned over an ulnar region or a radial region of the wrist of the patient. The method also may include inflating the expandable member to apply pressure to the ulnar region or the radial region. 
     In some aspects of the method, the expandable member comprises a bladder, and inflating the expandable member comprises inflating the bladder to at least a pressure to cause compression of tissue near at least one of an ulnar artery or a radial artery of the patient. 
     In some aspects of the method, the tissue compression device is configured to partially surround the wrist when on the wrist of the patient in a first orientation and when on the wrist of the patient in a second, different orientation, and the step of positioning the tissue compression device on the wrist of the patient comprises positioning the tissue compression device in the first orientation such that the expandable member is positioned over the ulnar region, or the step of positioning the tissue compression device on the wrist of the patient comprises positioning the tissue compression device in the second orientation such that the expandable member is positioned over the radial region. 
     In some aspects of the method, positioning the tissue compression device on the wrist of the patient further comprises positioning the expandable member to apply pressure more directly to the ulnar region than to the radial region. 
     In some aspects of the method, positioning the tissue compression device on the wrist of the patient further comprises positioning the expandable member to apply pressure more directly to the radial region than to the ulnar region. 
     In some aspects of the method, the base comprises a substantially rigid thermoplastic or a substantially rigid thermoset plastic that resists deformation of the base when inflating the expandable member. 
     In some aspects of the method of, the base comprises a first section extending from a terminal end to a medial end, wherein positioning the tissue compression device comprises traversing, with the first section, one of a radial side of the wrist or an ulnar side of the wrist, a second section extending from a terminal end to a medial end, wherein positioning the tissue compression device comprises traversing, with the second section, the other of the radial side of the wrist or the ulnar side of the wrist when the base is on the wrist, and a third section extending between the medial end of the first section and the medial end of the second section. 
     In some aspects of the method, positioning the tissue compression device comprises the third section traversing a dorsal surface of the wrist when the base is on the wrist. In some aspects of the method, positioning the tissue compression device on a wrist of a patient comprises positioning the first section to extend from the dorsal surface of the wrist to a palmar surface of the wrist and positioning the second section to extend from the dorsal surface of the wrist to traverse at least a portion of one of a radial border of the wrist or an ulnar border of the wrist. 
     In some aspects of the method, the terminal end of the first section and the terminal end of the second section define a gap, and positioning the tissue compression device on the wrist of the patient comprises passing the wrist of the patient through the gap. 
     In some aspects of the method, positioning the tissue compression device comprises positioning the tissue compression device on a left wrist of the patient or a right wrist of the patient. 
     In some aspects of the method, the expandable member is adjustably mechanically connected to the base, and the method comprises, before inflating the expandable member, adjusting a position of the expandable member relative to the base. 
     In some aspects of the method, the expandable member comprises a protrusion extending from a surface of the expandable member, and positioning the tissue compression device on a wrist of a patient comprises positioning the protrusion to apply pressure to a tissue near an ulnar artery or a radial artery of the patient. 
     In some aspects of the method, the expandable member is a first expandable member, and the tissue compression device further comprises a second expandable member mechanically connected to the base, and positioning the tissue compression device on a wrist of a patient comprises positioning the first expandable member over the ulnar region of the wrist of the patient to apply pressure to the ulnar region when the base engages at least the portion of the wrist and positioning the second expandable member over the radial region of the wrist of the patient when the base engages at least the portion of the wrist. The method further includes inflating the first expandable member to apply pressure to the ulnar region, and inflating the second expandable member to apply pressure to the radial region. 
     In some aspects of the method, the first expandable member comprises a first bladder and the second expandable member comprises a second bladder, wherein inflating the first expandable member comprises inflating the first bladder to at least a pressure to cause compression of tissue near an ulnar artery of the patient, and wherein inflating the second expandable member comprises inflating the second bladder to at least a pressure to cause patent hemostasis of a vascular access site at the radial artery of the patient. 
     The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a conceptual perspective view of an example non-circumferential tissue compression device including a base and an expandable member. 
         FIGS. 2A-2D  are conceptual perspective views of an example non-circumferential tissue compression device including a base and an expandable member having a protrusion. 
         FIGS. 3A-3E  are conceptual perspective views of an example non-circumferential tissue compression device including a base and two expandable members. 
         FIG. 4  is a flow diagram illustrating an example method of assembling a non-circumferential tissue compression device including a base and an expandable member. 
         FIG. 5  is a flow diagram illustrating an example method of using a non-circumferential tissue compression device including a base and an expandable member. 
     
    
    
     DETAILED DESCRIPTION 
     Percutaneous coronary procedures with transradial access include accessing vasculature of a patient via an access site, e.g., radial artery access site. The amount of blood flow in the radial artery may affect the ease of access to the radial artery or, once in the radial artery, access through the radial artery to other sites in the vasculature. For example, it is believed that increased blood flow in the radial artery may increase a diameter of the radial artery, and a larger diameter radial artery may enable easier navigation of a guide device (e.g., a guidewire or a guide catheter) or other medical device through the radial artery to a treatment site in the patient. Blood flow in the radial artery may be increased by compression of the ulnar artery, which may facilitate access of the radial artery. 
     The disclosure describes non-circumferential tissue compression devices configured to apply pressure to an ulnar region, a radial region, or both the ulnar and radial regions of a patient, as well as techniques for forming and using the non-circumferential tissue compression devices. The ulnar region may include selected tissue near (e.g., superficial to) an ulnar artery and/or an ulnar vein of the patient. The radial region may include selected tissue near (e.g., superficial to) a radial artery and/or a radial vein of the patient. Example non-circumferential tissue compression devices described herein are configured to apply pressure to tissue at the ulnar region, a radial region, or both to compress at least one of the ulnar artery, the ulnar vein, the radial artery, or the radial vein. 
     In contrast to some circumferential tissue compression devices, the non-circumferential tissue compression devices described herein are configured to apply pressure to less than the entire outer perimeter of a wrist of a patient at a particular time. In this way, the tissue compression device may be configured to more selectively (e.g., more directly) apply pressure to only one of the ulnar region or the radial region at a time. For example, the tissue compression device may be configured to apply pressure to only one of the ulnar region or the radial region while not applying pressure to the other of the ulnar region or the radial region or while applying substantially less pressure to the other of the ulnar region or the radial region. The substantially less pressure can be, for example, pressure that does not result in a physiologically significant change to blood flow in the one of the ulnar region or the radial region. 
     The non-circumferential tissue compression device may include a base and an expandable member mechanically connected to the base. The base may include a surface configured to, when on the wrist of the patient, surrounds or engages a portion of the wrist of the patient in a non-circumferential configuration. For example, the surface may surround or engage with less than a full outer perimeter of the wrist of the patient. The non-circumferential configuration may include a “C” shape configured to allow a clinician to fit the tissue compression device onto the wrist of the patient, orient the tissue compression device to engage the wrist of the patient, and to enable the expandable member to be inflated without becoming disengaged with the wrist of the patient. For example, the base and/or base surface may define an arc extending between greater than about 180 degrees to less than 360 degrees. 
     In some examples, the expandable member may include a single expandable chamber, e.g., balloon. A single expandable member may be configured to apply pressure to the ulnar region, the radial region, or both regions simultaneously. In some examples, the expandable member may include a plurality of expandable members. The plurality of expandable members may be configured to individually or collectively apply pressure to the ulnar region, the radial region, or both regions simultaneously. In some examples, the non-circumferential tissue compression device may be reversible such that in a first orientation the expandable member may be oriented over the ulnar region and not over the radial region, and in a second, different (e.g., reversed) orientation the expandable member may be oriented over the radial region and not over the ulnar region. 
     In this way, the tissue compression device is configured to apply pressure to selected tissue beneath the expandable member, e.g., to tissue that transmits the pressure to at least one of the ulnar artery, ulnar vein, the radial artery, or the radial vein. It is believed that ulnar artery compression may improve the outcomes or ease of transradial percutaneous coronary procedures by facilitating access to the vasculature of the patient. For example, a weak radial pulse due to a relatively small radial artery, a relatively deep radial artery, or hypotension may make vasculature access by arteriotomy of the radial artery difficult. It is believed that ulnar compression may be used to improve accuracy and speed of vasculature access via arteriotomy of the radial artery by making radial pulse stronger and/or enlarging the radial artery to improve success rate of fingertip palpitation-guided access to the radial artery. 
     In some cases, pressure applied to the access site after the procedure to achieve patent hemostasis may result in radial artery occlusion (e.g., acute and/or chronic radial artery occlusion). Radial artery occlusion may be caused by acute thrombosis due to intimal abrasion and changes in the vessel in conjunction with blood flow cessation when pressure is applied to the radial artery access site (e.g., radial compression) to achieve hemostasis. Radial artery occlusion may be undesirable. For example, radial artery occlusion may limit future ipsilateral transradial access, cause transient discomfort to the patient, or any combination thereof. 
     It is believed that ipsilateral ulnar artery compression (also referred to as ulnar compression) may maintain or increase radial artery blood flow to facilitate access of the radial artery or, during radial compression, to reduce incidence of radial artery occlusion compared to other methods alone, such as compared to the use of a low sheath (part of the percutaneous access device) to artery size ratio, the use of intraprocedural heparin, or the maintenance of radial artery patency during hemostasis after transradial access. Ulnar compression may result in complete or near complete occlusion of the ulnar artery to increase blood flow in the radial artery. The increased blood flow in the radial artery may enable compression of the radial artery with a pressure sufficient to achieve hemostasis at the transradial access site without causing radial artery occlusion. 
     While circular tissue compression devices are useful, the non-circumferential tissue compression devices described herein are configured to more selectively apply pressure to one of the ulnar region or the radial region, or both regions simultaneously, which may facilitate radial artery access, shorten the time to achieve patent hemostasis, reduce incidence of radial artery occlusion, improve the healing process after percutaneous coronary procedures with transradial access, and improve patient comfort compared to other methods, such as tissue compression with a circumferential tissue compression band. 
       FIG. 1  is a conceptual perspective view of an example non-circumferential tissue compression device  100  including a base  102  and an expandable member  106 . Non-circumferential tissue compression device  100  is configured to receive and engage a wrist of a patient to apply pressure to selected tissue at the ulnar region, the radial region, or both the ulnar region and the radial region (e.g., aligned with but superficial to at least one of the ulnar artery, ulnar vein, the radial artery, or the radial vein) of the patient to thereby apply pressure to the respective at least one of the ulnar artery ulnar vein, the radial artery, or the radial vein. Base  102  is configured to partially surround a wrist of a patent and not fully surround the wrist, e.g., as in a bracelet type configuration. For example, base  102  includes a first surface  104  configured to, when on the wrist of the patient, surround or engage at least a portion of the wrist in a non-circumferential configuration. Base  102  and/or first surface  104  may, therefore, be referred to as a non-circumferential base  102  or a non-circumferential surface  104 , respectively. Base  102  also defines a second surface  108  on an opposite side of base  102  from surface  104 . Surfaces  104 ,  108  face in different directions. 
     First surface  104  may have any suitable shape configured to engage with at least a portion of the wrist and/or forearm of the patient. For example, base  102  and/or first surface  104  may have a non-circumferential “C” shape that corresponds to an anatomical shape of at least part of the wrist of a patient (e.g., mimics the general outline of the wrist or part of the wrist, such as the dorsal surface of the wrist, the ulnar side of the wrist (e.g., ulnar border), and the radial side of the wrist (e.g., radial border). The non-circumferential “C” shape may define an arc extending between greater than about 180 degrees to less than 360 degrees, such as, for example, about 200 degrees to about 320 degrees or about 270 degrees. By extending greater than about 180 degrees, a force may be applied by expandable member  106  to the wrist of the patient at a first end (e.g., terminal end  116 ) of non-circumferential tissue compression device  100 , and the force may be counteracted at least at a second end (e.g., terminal end  120 ) of non-circumferential tissue compression device  100  such that the expandable member  106  compresses tissue beneath expandable member  106 , rather than dislodging non-circumferential tissue compression device  100  from the wrist of the patient. 
     In addition, by extending less than about 360 degrees, non-circumferential base  102  may define a gap  124  configured to enable a clinician to fit non-circumferential tissue compression device  100  to a wrist of the patient. In some examples, first surface  104  may have a shape that corresponds to an anatomical shape of both the right hand and the left hand of the patient, e.g., first surface  104  may be ambidextrous. In other examples, first surface  104  may have other shapes, such as elliptical, rectangular, or irregular shapes. In this way, the shape of first surface  104  may be selected to allow a clinician to fit base  102  onto the wrist of the patient, orient the tissue compression device  100  to engage the wrist of the patient, and to enable expandable member  106  to be inflated without becoming disengaged with the wrist of the patient 
     In some examples, base  102  may include a plurality of connected sections or segments. For example, base  102  may include a first curved section  110 , a second curved section  112 , and a substantially straight section  114 . First curved section  110  and second curved section  112  are each example structures configured to hold non-circumferential tissue compression device  100  on the wrist of the patient when expandable member  106  is inflated. First curved section  110  extends from a terminal end  116  to a medial end  118 . First curved section  110  is configured to extend around or engage one of a radial side of the wrist or an ulnar side of the wrist. For example, when the wrist is engaged with first surface  104 , first curved section  110  may extend from the dorsal surface of the wrist to a palmar surface of the wrist (e.g., traversing the ulnar border of the wrist or the radial border of the wrist) to surround or engage at least a portion of the ulnar border of the wrist or the radial border of the wrist. By surrounding or engaging at least a portion of the ulnar border of the wrist or the radial border of the wrist, first curved section  110  may reduce movement of non-circumferential tissue compression device  100  when expandable member  106  is inflated to prevent dislodgement of base  102  from the wrist of the patient. 
     Second curved section  112  extends from a terminal end  120  to a medial end  122 . Second curved section  112  is configured to surround or engage the other of the radial side of the wrist or the ulnar side of the wrist. For example, second curved section  112  may extend from the dorsal surface of the wrist to traverse at least a portion of one of the radial border of the wrist or the ulnar border of the wrist be configured to engage at least a portion of the radial border of the wrist of the patient when the wrist is engaged with first surface  104 . By surrounding or engaging at least a portion of the ulnar border of the wrist or the radial border of the wrist, second curved section  112  may reduce movement of non-circumferential tissue compression device  100  when expandable member  106  is inflated to prevent dislodgement of base  102  from the wrist of the patient. 
     Substantially straight section  114  extends between medial end  118  of first curved section  110  and medial end  122  of second curved section  112 . Substantially straight section  114  may be straight or nearly straight, e.g., compared to first curved section  110  and/or second curved section  114 . By extending between first curved section  110  and second curved section  112 , substantially straight section  114  may reduce movement of first curved section  110  relative to second curved section  112  to facilitate engagement of the ulnar border and radial border by the respective first curved section  110  and second curved section  112 . 
     Terminal end  118  of first curved section  110  and terminal end  120  of second curved section  112  define a gap  124 . Gap  124  is sized to enable a clinician to position non-circumferential tissue compression device  100  on the wrist of the patient. For example, gap  124  may be at least as wide as a projection of the wrist (e.g., the projection taken from the ulnar border or radial boarder), such that the wrist may pass through gap  124 . In some examples, gap  124  may have a width between about 2.5 centimeters to about 6 centimeters. In some examples, terminal end  118  may contact or nearly contact terminal end  120 , e.g., gap  124  may be between about 0 cm and about 2.5 cm, when not positioned on a wrist of the, and a clinician may apply a force to non-circumferential tissue compression device  100  to open gap  124  while positioning non-circumferential tissue compression device  100  on the wrist of the patient. After a portion of the wrist is received within gap  124 , non-circumferential tissue compression device  100  may be rotated to surround the desired portion of the wrist, e.g., such that substantially straight section  114  traverses the dorsal surface of the wrist. In some examples, non-circumferential tissue compression device  100  may include one or more straps or claps traversing gap  124 . The one or more straps or clasps may be configured to prevent non-circumferential tissue compression device  100  from falling off the wrist or moving relative to the wrist. The one or more straps or clasps may not apply pressure to the wrist of the patient or may not even contact the wrist of the patient. 
     In some examples, base  102  is formed from one or more substantially rigid materials. A substantially rigid material may include a material having an apparent modulus of rigidity (e.g., apparent shear modulus of elasticity) in ambient conditions sufficient to reduce deflection of base  102  when first surface  104  is positioned to surround or engage the wrist of the patient and expandable member  106  is expanded to apply pressure to the ulnar region and/or the radial region. For example, a substantially rigid material may include a material having an apparent shear modulus of at least approximately 0.1 gigapascal (GPa). In some examples, the substantially rigid material may include enough flexibility to enable a clinician to deform non-circumferential tissue compression device  100  for fitting to the wrist of the patient, e.g., to sufficiently widen gap  124  to fit over the wrist of the patient. After deforming non-circumferential tissue compression device  100  to fit around the wrist of the patient, the substantially rigid material may include enough elasticity to return, or nearly return, to the original shape. In this way, non-circumferential tissue compression device  100  may be configured to accommodate a selected range of wrist sizes, such as from patients with a less than average wrist diameter to patients with a greater than average wrist diameter. In some examples, base  102  includes one or more substantially rigid thermoplastics, such as acrylonitrile butadiene styrene (ABS), polyethylene, polycarbonate, polyamide, high impact polystyrene, polypropylene, or polyoxymethylene; or substantially rigid thermoset plastics, such as polyester, polyurethane, or epoxy resin. 
     Base  102  can be entirely rigid in some examples, while in other examples, base  102  may include one or more flexible regions or joints configured to improve patient comfort when non-circumferential tissue compression device  100  is retained on the wrist of the patient. For example, substantially straight section  114  may extend between a first joint region adjacent medial end  118  of first curved section  110  and a second joint region adjacent medial end  122  of second curved section  112 . Each of the first and second joint regions may include a substantially flexible material configured to allow base  102  to bend or deflect at first joint region or second joint region in response to a force, such as forces pulling terminal ends  116  and  120  in opposing directions. In this way, first joint region or second joint region may enable a clinician to bend base  102  to widen gap  124  when positioning non-circumferential tissue compression device  100  on the wrist of the patient, as discussed above. 
     Expandable member  106  may be mechanically connected to first surface  104  of base  102 . Expandable member  106  is configured to be positioned over the ulnar region (e.g., and not the radial region), the radial region (e.g., and not the ulnar region), or both the ulnar region and the radial region of the wrist of the patient when base  102  is engaged with the portion of the wrist. Expandable member  106  also is configured to apply pressure to the ulnar region and/or the radial region. For example, expandable member  106  may be configured to apply pressure to only one of the ulnar region or the radial region while not applying pressure to the other of the ulnar region or the radial region or while applying substantially less pressure to the other of the ulnar region or the radial region. 
     In some examples, expandable member  106  may include a pad disposed on first surface  104 , e.g., along substantially straight section  114 . The pad may be configured to engage with a dorsal surface of the wrist of the patient when the wrist is positioned on first surface  104  to improve patient comfort. In some examples, the pad is formed from a softer, more pliable material than base  102 . For example, the pad may include any suitable material, such as silicone, rubber, polyethylene, or a thermoplastic or thermoset plastic. In some examples, the pad may include an inflatable balloon configured to adjustably control the size and/or rigidity of the pad. Adjustable control of the size and/or rigidity of the pad may enable non-circumferential tissue compression device  100  to accommodate different wrist sizes or shapes and adjust the extent to which the pad extends from first surface  104 . The pad may be integrally formed with base  102  or adjustably mechanically connected to base  102  by, for example, an adhesive, a hook-and-loop fastener, or any other suitable fastener or combination of fasteners. 
     In some examples, expandable member  106  includes a coating or other material to increase the static friction between the wrist of the patient and expandable member  106 , which may reduce any undesirable relative movement between the hand and non-circumferential tissue compression device  100 . 
     Expandable member  106  is configured to be positioned over the ulnar region, the radial region, or both when non-circumferential tissue compression device  100  is retained on the wrist of the patient. Although illustrated in  FIG. 1  as covering substantially the entire first surface  104 , in other example, expandable member  106  may cover one or more portions of first surface  104 , such as a portion of first surface  104  at first curved section  110  or a portion of first surface  104  at second curved section  112 . 
     Expandable member  106  may be mechanically connected to base  102  by any suitable means, such as, for example, an adhesive, thermal bonding, welding, or a mechanical fastener, e.g., by a hook-and-loop fastener. In other examples, expandable member  106  may be integrally formed with base  102 , such that a position of expandable member  106  is fixed relative to base  102 . For example, base  102  may include two or more layers forming a pocket and defining expandable member  106 . In some examples, expandable member  106  may be secured in place to base  102  at a location that positions expandable member over the ulnar region and/or radial region when non-circumferential tissue compression device  100  is retained on the wrist of the patient. 
     In some examples, expandable member  106  may be removably secured to base  102  such that a clinician may adjust the position of expandable member  106  relative to base  102 . For example, expandable member  106  may be connected to base  102  via an adhesive, such as a pressure-sensitive adhesive or a removable adhesive, or a mechanical fastener, such as a hook-and-loop mechanism, and a clinician may detach expandable member  106  from base  102  by pulling expandable member  106  away from base  102  and then subsequently use the adhesive or hook-and-loop mechanism to reattach expandable member  106  to base  102  at a different location. In this way, a clinician may adjust the position of expandable member  106  relative to base  102  prior to retaining non-circumferential tissue compression device  100  on the wrist of the patient. 
     In some examples, base  102 , expandable member  106 , or both may include a transparent material or a window including a transparent material, the window positioned on base  102  to be substantially over an access site, such as a radial access site, when retained on the wrist of the patient. The transparent material may enable a clinician to visualize an access site while non-circumferential tissue compression device  100  is retained on the wrist of the patient. In contrast, if base  102  and expandable member  106  were entirely opaque, a clinician may not be able to view the access site. By visualizing the access site, the clinician may visually confirm patent hemostasis. 
     Expandable member  106  is configured to apply pressure to selected tissue at the ulnar region, radial region, or both when non-circumferential tissue compression device  100  is retained on the wrist of the patient to facilitate access to the vasculature of the patient, to help reduce incidence of radial artery occlusion after percutaneous coronary procedures with transradial access, or both. Expandable member  106  may define any suitable shape having any suitable surface area to apply pressure to selected tissue at the ulnar region and/or radial region. For example, a surface  126  of expandable member  106  may include the non-circumferential “C” shape as described above in reference to first surface  104  of base  102 . For example, surface  126  may be configured to engage with selected tissue at the ulnar region and/or radial region of a patient. In other examples, surface  126  may define one or more similar or different geometric shapes, such as an ellipse, a quadrilateral or other polygon, or irregular shapes. 
     In some examples, surface  126  is configured to apply a substantially uniform pressure to tissue of a patient when expandable member  106  is inflated. In other examples, surface  126  may define one or more protrusions configured to increase pressure at a selected point when expandable member  106  is inflated. For example, a first protrusion may be positioned on surface  126  such that the protrusion is oriented over an ulnar region or a radial region when non-circumferential tissue compression device  100  is engaged with the wrist of the patient. Additionally, expandable member  106  define any suitable volume to achieve a selected pressure on the selected tissue at the ulnar region and/or radial region. For example, expandable member  106 , when in a deflated configuration or an inflated configuration, may extend any suitable distance from first surface  104  of base  102  (or from surface  126  of expandable member  106 ). 
     Expandable member  106  may include one or more bladders (not shown, “the bladder”) fluidically connected to a channel  128 . Channel  128  may be fluidically connected to one or more inflation devices  130  configured to inflate the bladder of expandable member  106  and one or more deflation devices  132  configured to deflate the bladder of expandable member  106 . For example, inflation device  130  may include a pump configured to controllably inflate the bladder of expandable member  106  or a syringe configured to controllably inflate the bladder of expandable member  106 . 
     Deflation device  132  may include a release valve configured to deflate the bladder of expandable member  106 . In some examples, a clinician may use deflation device  132  to uncontrollably and fully deflate the bladder of expandable member  106 , e.g., prior to removing non-circumferential tissue compression device  100  from the hand of the patient. In other examples, deflation device  132  may more controllably deflate the bladder of expandable member  106  to compress of the ulnar region and/or radial region. For example, with respect to compression of the ulnar region prior to access at the radial artery, a clinician may inflate the bladder of expandable member  106  using inflation device  130  to a first pressure that is greater than a minimum pressure to achieve the desired compression of the ulnar region, e.g., the clinician may inflate the bladder of expandable member  106  until the clinician observes at least partial occlusion of the ulnar artery distal to the bladder of expandable member  106  or ulnar vein proximal to the bladder of expandable member  106  by, for example, palpitation, ultrasonography, pulse-oximetry, or modified Allen&#39;s test (e.g., the hand of the patient may be elevated, the hand may be clenched in a fist for about 30 seconds, pressure may be applied over the ulnar artery and the radial artery so as to occlude both arteries while the hand is clenched in the fist, the elevated hand may be subsequently unclenched, the color of the hand may be observed as blanched or pallor may be observed at the finger nails, ulnar artery pressure may be released while radial artery pressure is maintained, and the time for color to return to the hand is observed). 
     After inflating the bladder of expandable member  106  to the first pressure, the clinician may controllably deflate the bladder of expandable member  106  using deflation device  132  to a second pressure slightly less than the minimum pressure to achieve occlusion of the ulnar artery, e.g., the clinician may deflate the bladder of expandable member  106  until the clinician observe return ulnar artery blood flow. After deflating the bladder of expandable member  106  to the second pressure, the clinician may inflate the bladder of expandable member  106  by a predetermined volume, such as, for example, 1 cubic centimeter to 20 cubic centimeters of air, to a third pressure and confirm at least partial occlusion of the ulnar artery. By controllably deflating the bladder of expandable member  106  to the second pressure, the clinician may more accurately inflate the bladder of expandable member  106  to the third pressure using the predetermined volume to sufficiently compress the ulnar region to increase blood flow or blood pressure in the radial artery. 
     The bladder of expandable member  106  may be configured to inflate to at least a pressure that provides at least partial occlusion of the ulnar artery, patent hemostasis of a transradial access site, or both. In some examples, inflation of the bladder of expandable member  106  will tend to move surface  126  of expandable member  106  away from first surface  104  of base  102 . When non-circumferential tissue compression device  100  is retained on the wrist of the patient, inflation of the bladder of expandable member  106  forces surface  126  of expandable member  106  against the tissue at at least one of the ulnar artery, the ulnar vein, the radial artery or the radial vein to provide compression of selected tissue in contact with surface  126  of expandable member  106 . In this way, expandable member  106  may inflate to apply a selected pressure to tissue at the ulnar region and/or radial region. 
       FIGS. 2A-2D  are conceptual diagrams illustrating an example non-circumferential tissue compression device  200  including a protrusion  207  on an expandable member  206 . Non-circumferential tissue compression device  200  may be the same as or substantially similar to non-circumferential tissue compression device  100  discussed above in reference to  FIG. 1 , except for the differenced described herein. For example, non-circumferential tissue compression device  200  may include a non-circumferential base  202  that includes a surface  204  configured to, when on a wrist of a patient, surround or engage at least a portion of the wrist in a non-circumferential configuration, and expandable member  206  mechanically connected to surface  204  of base  202 . Expandable member  206  is configured to be positioned over an ulnar region or a radial region of the wrist of the patient when base  202  is engaged with the portion of the wrist, and is configured to apply pressure to the ulnar region or the radial region. 
     As illustrated in  FIGS. 2A-2D , expandable member  206  includes protrusion  207 . Protrusion  207  is configured to apply pressure to a tissue near an ulnar artery or a radial artery of the patient. For example, when expandable member  206  is inflated, surface  226  of expandable member  206  may extend a first distance “D 1 ” from first surface  204  of base  202 . Protrusion  207  may extend a second distance “D 2 ” that is greater than D 1  from first surface  204  of base  202 . By extending farther from first surface  204  of base  202 , protrusions  207  may be configured to increase pressure at a selected point beneath protrusion  207  when expandable member  206  is inflated. 
     Protrusion  207  may include a non-expandable protrusion, e.g., a structure fixed to surface  226 , or an expandable protrusion, e.g., a structure integrally formed with expandable member  206 . In examples in which protrusion  207  is a non-expandable protrusion, protrusion  207  may be adjustably mechanically connected to surface  226  by for example, an adhesive, a hook-and-loop fastener, or any other suitable fastener or combination of fasteners. In this way, a clinician may adjust a position of protrusion  207  relative to base  102  such that protrusion  207  is oriented over a selected region, such as one of ulnar region  250  or radial region  252 , when base  102  is positioned on the wrist of the patient. Ulnar region  250  or radial region  252  are example regions and may vary between patients. A clinician may determine a location of ulnar region  250  or radial region  252 . In examples in which protrusion  207  includes an expandable protrusion, protrusion  207  may be fluidly coupled to expandable member  206  such that increasing a pressure within expandable member  206  increases a pressure within protrusion  207  or fluidly coupled to a second inflation device and/or second deflation device, such that a pressure of protrusion  207  may be control independent of a pressure of expandable member  207 . In this way, protrusion  207  may be configured to selectively apply pressure to a selected region, such as one of ulnar region  250  or radial region  252 , depending on the desired goal of the application of pressure when base  102  is positioned on the wrist of the patient. 
     Protrusion  207  may include any suitable shape configured to increase pressure at a selected point beneath protrusion  207 . As illustrated in  FIG. 2B , protrusion  207  includes a tapered rectilinear shape. In other examples, protrusion  207  may include a hemispherical shape, a conical shape, or another geometric or irregular shape configured to increase pressure at a selected point beneath protrusion  207 , such as shape corresponding to an anatomical shape of an ulnar region or a radial region. 
     In some examples, non-circumferential tissue compression device  200  may include a plurality of protrusions. For example, non-circumferential tissue compression device  200  may include a first protrusion and a second protrusion. The first protrusion may be positioned on surface  226  such that the first protrusion is oriented over an ulnar region when non-circumferential tissue compression device  200  is engaged with the wrist of the patient. The second protrusion may be positioned on surface  226  such that the second protrusion is oriented over a radial region when non-circumferential tissue compression device  200  is engaged with the wrist of the patient. In this way, a plurality of protrusions may increase pressure at a plurality of selected points beneath a respective plurality of protrusions when expandable member  206  is inflated. 
     As discussed above, non-circumferential tissue compression device  200  may be reversible. For example, as illustrated in  FIG. 2C , in a first orientation of tissue compression device  200 , protrusion  207  may be positioned over ulnar region  250  (indicated by dashed lines) of wrist  254  of the patient and not over radial region  252  (indicated by dashed lines) of wrist  254 . As illustrated in  FIG. 2D , when in tissue compression device  200  is in a second, different (e.g., reversed) orientation, protrusion  207  may be positioned over radial region  252  and not over ulnar region  250 . A clinician may change the orientation of non-circumferential tissue compression device  200  during a percutaneous coronary procedure. For example, the clinician may position non-circumferential tissue compression device  200  on wrist  254  of patient in the first orientation ( FIG. 2C ) before arteriotomy to at least partially occlude the ulnar artery which, as discussed above, may facilitate access at the radial artery. After arteriotomy, e.g., prior to application of pressure to the access site, the clinician may remove non-circumferential tissue compression device  200  for wrist  254 , and refit non-circumferential tissue compression device  200  in the second orientation ( FIG. 2D ) which, as discussed above, may be used to apply pressure to the access site to achieve patent hemostasis of the access site. In this way, non-circumferential tissue compression device  200  may be configured to selectively apply pressure to only one of ulnar region  250  or radial region  252 , depending on the desired goal of the application of pressure. 
     In some examples, a non-circumferential tissue compression device may include a plurality of expandable members.  FIGS. 3A-3C  are conceptual diagrams illustrating an example tissue compression device including a base  302  and two expandable members  306 A and  306 B (collectively, “expandable member  306 ”). Non-circumferential tissue compression device  300  may be the same as or substantially similar to non-circumferential tissue compression devices  100  and  200  discussed above in reference to  FIGS. 1-2D , except for the differenced described herein. For example, non-circumferential tissue compression device  300  may include base  302  that include a surface  304  configured to, when on a wrist of a patient, surround or engage at least a portion of the wrist in a non-circumferential configuration, and expandable member  306  mechanically connected to surface  304  of base  302 . Expandable member  306  is configured to be positioned over an ulnar region or a radial region of the wrist of the patient when base  302  is engaged with the portion of the wrist, and is configured to apply pressure to the ulnar region or the radial region. 
     As illustrated in  FIGS. 3A-3D , expandable members  306 A and  306 B may be positioned near opposite ends of base  302 . For example, first expandable member  306 A may be positioned near terminal end  316  of first curved section  310 . Second expandable member  306 B may be positioned near terminal end  320  of second curved section  312 . Positioning expandable member  306  near respective terminal ends  316  and  320  may enable a clinician to position non-circumferential tissue compression device  300  on the wrist of the patient such that expandable members  306  are oriented over a respective ulnar region or radial region. 
     For example, as illustrated in  FIG. 3C , in a first orientation, first expandable member  306 A may be oriented over ulnar region  350  (indicated by dashed lines) of wrist  354  of the patient and not over radial region  352  (indicated by dashed lines) of wrist  354 , and second expandable member  306 B may be oriented over radial region  352  and not over ulnar region  350 . As illustrated in  FIG. 3D , in a second, different (e.g., reversed) orientation, expandable member  306 A may be oriented over radial region  352  of wrist  354  of the patient and not over ulnar region  350  of wrist  354 , and expandable member  306 B may be oriented over ulnar region  350  and not over radial region  352 . In this way, as discussed above in reference to  FIGS. 2C and 2D , a clinician may change the orientation of non-circumferential tissue compression device  300  during a percutaneous coronary procedure. 
     In some examples, expandable members  306 A,  306 B may be fluidly coupled by a connecting tube  334 . Fluidly coupling expandable members  306 A,  306 B with connecting tube  334  may enable expandable members  306 A,  306 B to be inflated with a single inflation device (e.g., inflation device  130 ) and/or deflated with a single deflation device (e.g., deflation device  132 ). In other examples, each of first expandable member  306 A and second expandable member  306 B are fluidically separate from each other and may be fluidly coupled to respective inflation devices and respective deflation devices. In this way, a pressure of each of first expandable member  306 A and second expandable member  306 B may be independently controlled. For example, before arteriotomy of the radial artery, first expandable member  306 A oriented over ulnar region  350  may be inflated to at least partially occlude the ulnar artery which, as discussed above, may facilitate access at the radial artery. After arteriotomy of the radial artery, e.g., prior to application of pressure to the access site, second expandable member  306 B oriented over radial region  352  may be inflated to apply pressure to the access site to achieve patent hemostasis of the access site at the radial artery. In this way, non-circumferential tissue compression device  300  may facilitate both ulnar compression (e.g., to improve accuracy and speed of vasculature access via arteriotomy of the radial artery by making radial pulse stronger and/or enlarging the radial artery to improve success rate of fingertip palpitation-guided access to the radial artery) and radial compression (e.g., to achieve hemostasis at the transradial access site without causing radial artery occlusion) without requiring the clinician to remove non-circumferential tissue compression device  300  from the wrist of the patient. 
     As discussed above in reference to  FIG. 1 , a non-circumferential tissue compression device may be configured to engage a left wrist of the patient, a right wrist of the patient, or both the left wrist and the right wrist of the patient. For example, as illustrated in  FIG. 3E , non-circumferential tissue compression device  300  may be fitted to the left wrist  354 L of the patient. In this way, non-circumferential tissue compression device  300  may enable both right and left transradial percutaneous coronary procedures. 
     The non-circumferential tissue compression devices described herein may be assembled using any suitable technique.  FIG. 4  is a flow diagram illustrating an example method of assembling a non-circumferential tissue compression device including a base and an expandable member. The non-circumferential tissue compression device may be the same as or substantially similar to non-circumferential tissue compression devices  100 ,  200 , and  300  discussed above with respect to  FIGS. 1-3E . Although  FIG. 4  is described with respect to non-circumferential tissue compression device  100 , in other examples, the technique illustrated in  FIG. 4  may be used to assemble other non-circumferential tissue compression devices, such as non-circumferential tissue compression device  200  or  300 , or other non-circumferential tissue compression devices including a base and an expandable member mechanically connected to the base. 
     In accordance with the technique illustrated in  FIG. 4 , a user or a device forms base  102  of non-circumferential tissue compression device  100  ( 402 ). Forming base  102  may include thermoforming or molding base  102 . Base  102  may include a substantially rigid material, such as a substantially rigid polymer, configured to be thermoformed to substantially conform to an anatomical shape of the wrist a patient or a substantially rigid thermoset plastic configured to be molded to substantially conform to an anatomical shape of the wrist of a patient. By thermoforming or molding base  102  to conform to an anatomical shape of the wrist of a patient, base  102  may be shaped to improve patient comfort, improve tissue compression at a selected area such as an ulnar region or radial region, or both. In examples in which base  102  includes a plurality of sections, each section may be formed together, or formed separately and subsequently connected, e.g., connected by forming a joint material between adjacent sections. 
     In examples in which base  102  includes a pad disposed on base  102 , assembling non-circumferential tissue compression device  100  may include positioning the pad on base  102  such that the pad is configured to engage at least a portion of the dorsal surface of the wrist of the patient to improve patient comfort when the dorsal surface of the wrist is engaged with first surface  104  of base  102 . 
     The technique illustrated in  FIG. 4  also may include forming expandable member  106 . In some example forming expandable member  106  may include thermoforming a flexible polymer to define the shape of expandable member  106 . 
     The technique illustrated in  FIG. 4  also includes attaching expandable member  106  to base  102  ( 404 ). For example, expandable member  106  may be attached to base  102  using an adhesive, thermal bonding, welding, or a mechanical fastener, e.g., by a hook-and-loop fastener. In examples in which expandable member  106  is integrally formed with base  102 , attaching expandable member  106  to base  102  may include forming a pocket in base  102  that defines expandable member  106 . 
     In some examples, the technique may include fluidly coupling inflation device  130 , deflection device  132 , or both to expandable member  106 . 
     The tissue compression devices describe herein may be retained on a hand of a patient using any suitable technique.  FIG. 5  is a flow diagram illustrating an example method of using a non-circumferential tissue compression tissue compression device including a base and an expandable member. The non-circumferential tissue compression device may be the same as or substantially similar to non-circumferential tissue compression devices  100 ,  200 , and  300  discussed above with respect to  FIGS. 1-3E . Although  FIG. 5  is described with respect to non-circumferential tissue compression device  100 , in other examples, the technique illustrated in  FIG. 5  may be used with other non-circumferential tissue compression devices, such as non-circumferential tissue compression device  200  or  300 , or other non-circumferential tissue compression devices including a base and an expandable member mechanically connected to the base. 
     The method shown in  FIG. 5  includes positioning non-circumferential tissue compression device  100  around at least a portion of a wrist of a patient ( 502 ). In some examples, a user may pass a wrist of the patient through gap  124 . In some examples, the user may deform non-circumferential tissue compression device  100  for fitting to the wrist of the patient, e.g., to sufficiently widen gap  124  to fit over the wrist of the patient. 
     The method of  FIG. 5  also includes positioning expandable member  106  over selected region, such as an ulnar region, a radial region, or both the ulnar region and the radial region of the patient ( 504 ). For example, after fitting non-circumferential tissue compression device  100  to the wrist, the user may rotate non-circumferential tissue compression device  100  around the wrist to orient expandable member  106  over the selected region. In some examples, expandable member  106  is movable relative to base  102 , and a user may detach expandable member  106  from base  102  and then subsequently reattaching expandable member  106  to base  102  at a different location, thereby enabling a user to adjust the position of expandable member  106  relative to base  102  and the wrist of the patient. 
     The method of  FIG. 5  also includes inflating expandable member  106  to apply pressure to tissue at the selected region ( 506 ). For example, expandable member  106  includes the bladder such that inflating expandable member  106  includes inflating the bladder of expandable member  106  to cause compression of tissue near the selected region. In some examples, base  102  includes a substantially rigid thermoplastic or a substantially rigid thermoset plastic such that when tissue compression device  100  is retained on the wrist of the patient increasing pressure in expandable member  106  results in increasing pressure on selected tissue at the selected region. 
     In examples in which tissue compression device  100  includes second expandable member, the technique may include adjusting a position of second expandable member to position second expandable member over a second selected region, such as an ulnar region, a radial region, both the ulnar region and the radial region of the patient, or a transradial access site. The technique also may include, after adjusting a position of second expandable member, inflating second expandable member to apply pressure to second selected region. For example, the second selected region may include a transradial access site, such that inflating the second expandable member may cause patent hemostasis of a vascular access site at the radial artery. 
     Various examples have been described. Any combination of the described systems, devices, operations, or functions is contemplated. These and other examples are within the scope of the following claims.