Abstract:
Percutaneous endovascular delivery of cardiac prosthetic devices is described through deep vascular access. Specifically, minimally intrusive access is achieved at points in the vascular tree having a size not usually achievable with existing tools. Localizing guide wires having visualization markings enable controlled passage through the vascular system.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/419,758 filed Dec. 3, 2010, which application is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    Percutaneous endovascular delivery of devices such as a diagnostic devices, surgical devices, tools, or implants, herein referred to as surgical devices or delivered devices, has become a common means of performing minimally invasive procedures on patients. Such procedures provide for reductions in risks, cost, and time to recovery over more traditional standard surgical and laparoscopic procedures. 
         [0003]    Such procedures typically follow a protocol which incorporates the following steps and components. A needle is placed percutaneously to access an intravascular location at the access site. A guide wire is then delivered thru the needle to the target site. The needle is then removed by sliding it proximally off of the proximal end of the guide wire, leaving the guide wire in place. After the removal of the needle, an introducer catheter is tracked down the guide wire into the vessel. The introduction of the introducer catheter may incorporate the use of a dialator to increase the size of the path. The delivered device is then delivered, typically over the guide wire and through the introducer catheter, to the target site. Of particular interest is the delivery of percutaneously delivered heart valves using such a technique. 
         [0004]    Proper access points must be used to facilitate such a procedure. A number of the primary characteristics for an appropriate access site are ease of localization from the surface of the body and a vessel size of appropriate diameter to support the devices being delivered. Typically, access via the femoral arteries is acceptable because these structures are easily localized via palpitation, have relatively large diameters, and directly interface with the aortic trunk. However, in some cases, the femoral arteries may not be able to support such procedures. Such as, the size of the femoral or subclavian artery is too small or tortuous, and an alternative site either past any tortuousity or of larger diameter is required. Such conditions can also be the result of anatomical anomalies, frailty of the tissue, stenosis and or calcification at the site or some intervening location, as the result of a medical condition, amongst other reasons. Additionally, the procedure of delivering the device to the deep vessel access site requires the physician to perform the access step while maintaining x-ray imaging. In such a procedure the physician&#39;s hands will likely be in the field of view of the fluoroscope during the portion of the procedure when performing the deep vascular access guide wire and introducer placement. The accumulated exposure to the physician&#39;s hands in such a situation could have serious long-term consequences. In these situations an alternate means of providing access to vasculature of appropriate diameters which are deeper and more difficult to reach is required. Alternative sites are available but hard to reach as the larger diameter artery portions are deeper in the tissue and cannot easily be palpitated etc. At present, in such situations, more invasive procedures may be required such as apical approaches for heart valve replacement, which do not have the advantages listed above. 
         [0005]    Accordingly, it would be a great advantage to provide for a means of accessing locations in the vascular tree which are of appropriate size and have less critical circulatory targets and can support the introduction of surgical devices, but are at present difficult or impossible to access with present day tools. 
         [0006]    Moreover, an ideal apparatus would not require a major investment in capital equipment but would still facilitate the percutaneous placement of introducer sheaths, and thereby provide access for the delivery of surgical devices to deep vascular access sites. 
       SUMMARY OF INVENTION 
       [0007]    One means of providing such deep vascular access is the use of two guide wires and two access points. One of the guide wires is a localizing guide wire delivered via access through a small vessel to the target access site. The localizing guide wire, which is visible by traditional xray means, can be used as a visual target to localize the site where the second guide wire is to be placed. The second or deep vascular access guide wire then becomes the track by which the deep vascular access introducer is placed. The size of the vessel along the localizing guide wire path may be ascertained via traditional methods aiding the physician in localizing an appropriate deep vascular access site. In such a procedure, a specialized guide wire carries markings to delineate specific positions along the guide wire under fluoroscopy that enables the physician to identify discrete target sites where the vessel diameter becomes large enough to support the deliverable device. 
     
    
     
       DESCRIPTION OF FIGURES 
         [0008]      FIG. 1  is a guide wire incorporating localization elements along a length of the distal end thereof. 
           [0009]      FIG. 2  is multiple embodiments of a sheath with a localization element on a guide wire. 
           [0010]      FIG. 3  shows a guide wire with an alternate set of localization elements. 
           [0011]      FIG. 4  shows a deep access introducer needle and guidewire. 
           [0012]      FIG. 5  shows a needle guide fixture. 
           [0013]      FIG. 6  shows a needle guide fixture along with an introducer needle and a localizing guide wire. 
           [0014]      FIG. 7  shows a bottom view of a needle guide fixture along with an introducer needle and a localizing guide wire. 
           [0015]      FIG. 8  shows a properly aligned needle guide fixture, introducer needle and a localizing guide wire as seen through a fluoroscope when the fluoroscope is also properly aligned. 
           [0016]      FIG. 9  shows a properly aligned needle guide fixture, introducer needle and a localizing guide wire as seen through a fluoroscope when the fluoroscope is not properly aligned. 
           [0017]      FIG. 10  shows an alternate configuration of a needle guide fixture, introducer needle and a localizing guide wire. 
           [0018]      FIG. 11  shows a view of an alternate configuration of a needle guide fixture, introducer needle and a localizing guide wire as seen through a fluoroscope when the system and fluoroscope are all properly aligned. 
           [0019]      FIG. 12  shows a view of an alternate configuration of a needle guide fixture, introducer needle and a localizing guide wire as seen through a fluoroscope when the system and fluoroscope are not properly aligned. 
           [0020]      FIG. 13  shows common major human arteries and possible access points for a localizing guide wire. 
           [0021]      FIG. 14  shows an aortic arch. 
           [0022]      FIG. 15  shows an aortic arch with a localizing guide wire in place. 
           [0023]      FIG. 16  shows an aortic arch with both a localizing guide wire and introducer needle in place. 
           [0024]      FIG. 17  shows an aortic arch with an introducer needle in place and a secondary guide wire delivered through the introducer needle and a localizing guide wire partially removed. 
           [0025]      FIG. 18  shows an aortic arch with a guide wire in place after complete or partial removal of a introducer needle and a localizing guide wire. 
           [0026]      FIG. 19  shows an aortic arch with an introducer catheter partially tracked down a guide wire. 
           [0027]      FIG. 20  shows an aortic arch with an introducer catheter in place. 
           [0028]      FIG. 21  shows an aortic arch with an introducer catheter in place and a percutaneous heart valve deployed after delivery through the introducer catheter. 
           [0029]      FIG. 22  shows an alternate needle guide fixture configured for remote adjustment. 
           [0030]      FIG. 23  shows an alternate needle guide fixture configured for remote adjustment with portions removed for better visualization of internal components. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0031]    The invention includes a system incorporating a guide wire and a deep access introducer device capable of measuring the proximity between the tip of the deep access introducer and the guide wire. More particularly, a system capable of characterizing both the proximity of the deep access introducer and the location along the guidewire of the deep access introducer is disclosed. 
         [0032]    The system and components thereof can be used as stand alone units or in combination with a localizing guide wire and deep access introducer to compliment the use of a deep vascular access guide fixture. The guide fixture provides a path along which the deep access introducer, or other trocars, may be advanced and the methods of the present invention describe advantageous and synergistic use of each component described below. Additionally, the cooperation between the guide fixture and the deep access introducer facilitates alignment of a path or track with the target access site on the localizing guide wire. 
         [0033]    Referring generally to  FIG. 1-3 , a localizing guide wire means is described having an electrical or fluoroscopic guide wire  12 , a movable element  13 , and one or more locational elements  11 . 
         [0034]    Referring to  FIG. 3 , a fluoroscopic localizing guide wire  10  is comprised of guide wire  12  incorporating multiple locational elements  11  comprising segments of radio opaque material of differing lengths where the length of the segment identifies the relative position where along the length of the guide wire. 
         [0035]    Referring to the multiple embodiments of  FIG. 2 , an electrical localizing guide wire  10  is disclosed comprising guide wire  12  incorporating a movable locational element  11  as part of a movable guide wire element  13 , the locational element  11  has a low impedance surface. The locational element  11  provides visible detection under fluoroscopy where the locational element  11  is movable to a target location via a movable element  13  that rides on guide wire element  12  and a deep access introducer  20  that senses the impedance between the locational element  11  and its tip  22 . By this combination, each of the locational element, the guide wire  12  and the introducer are localized both independently and relative to one another or where the guide fixture has 3 impedance sensors at 120 degrees and the three impedance measurements to element  11  define a set of parameters for setting the fixture. Impedance sensors as described herein may be either sources sinks or interchangeable, and any impedance system described herein incorporates at least one source. 
         [0036]    Referring to  FIG. 2 , guide wire  12  incorporates a moveable locational element  11  comprising a fiber optic. The distal fiber optic tip is visible under fluoroscopy, such that the tip is movable to a target location under fluoroscopy movable element  13 . Deep access introducer  20  comprising a tip  22  senses the optical output of the fiber optic and is localized relative to each other structure. 
         [0037]    Referring to  FIG. 2 , a localizing guide wire  12  incorporates a movable locational element  11  comprising an ultrasonic transducer, is visible under fluoroscopy, and is movable on the guide wire via a movable element  13 . The locational element  11  may additionally incorporate any combination of the following: the ability to characterize the mean cross sectional area of the surrounding vessel, the vessel wall thickness, aspects of the vessel wall compliance, and a deep access introducer incorporating an ultrasonic transducer capable of characterizing area, thickness, and the transducer&#39;s proximity to the ultrasonic transducer on the guide wire. The transducer may comprise a circular array. Different echos will indicate different boundaries associated with lumen and outer surface of vessel wall. Monitoring over time during a heart beat will provide information on vessel compliance. 
         [0038]    Referring to  FIG. 3 , a modification to the embodiment of  FIG. 1  provides a configuration wherein the guide wire  12  incorporates multiple stationary transducers along its length, each transducer signaling with a discrete and identifiable signal or pattern to distinguish each other and each transducer is additionally identifiable and distinct under fluoroscopy. 
         [0039]    Referring to  FIG. 4 , a deep access introducer needle optionally comprises a radio opaque tip comprising a fixture  22  selected from the group consisting of an ultrasonic transducer, a magnet or a magnetic field sensing transducer, an electric field generating element, an impedance sensing transducer, a light source, and a light sensing transducer and combinations thereof. 
         [0040]    Referring to  FIGS. 5-9 , a guide fixture  30  incorporates radio opaque target ring  33  and radio opaque target fins  32 . Telescoping standoff legs  31  may comprise ultrasonic transducers or impedance sensors, and deep access introducer needle guidance path  34 , which is aligned with the desired locational element  11  on the localizing guide wire  10 . See  FIG. 6 . Alignment is achieved when the corresponding individual signals between the ultrasonic transducers comprised in the guide fixture and the locational element  11  and the-deep access introducer needle  20  are approximately equal. In an alternate embodiment impedance measurements may be used instead of ultrasonic signals. See  FIG. 9 . 
         [0041]    Referring to  FIGS. 10-12 , fluoroscopic guide fixture  40  comprises radio opaque target rings  23 , a base  43 , a rotational stage  42 , and two piece deep access introducer needle guidance path comprised of the a channel created between removable guide half  41  and fixtured guide half  45 . The removable guide half aids in the removal of the system after the deep access guide wire has been placed. Alignment is achieved when the locational element  11  is centered in target rings  23 , typically by visual confirmation. On proper alignment, target ring images may additionally be circular as opposed to oval, and concentric.  FIG. 11  illustrates an aligned guide while  FIG. 12  illustrates a slightly misaligned guide. The target rings  23  are preferably circular, and in this configuration, appear oval when not properly aligned. The guide fixture  40  must be aligned with the focal plane of the fluoroscope. In general, all materials used in the fabrication of the fixture, except those used for the target rings are fabricated from materials with relatively low radioopacity. Rotational stage  42  and base  43  may be locked in place by drawing a vacuum at the interface surface (features not shown). In alternate designs the rotational stage may comprise a spherical section of greater then a hemisphere in which case the rotational stage may be clamped in place by arms extending from the base (not shown). 
         [0042]      FIG. 13  indicates two common alternate entry sites for the introduction of the locational guide wire when the femorals are not compatable. These are the radial artery and carotid artery as indicated. As shown, the introducer  50  is then delivered via one of the brachial arteries. 
         [0043]    The practical use of the devices described above is as follows. Although, those at ordinary skill will appreciate that variances in the procedures will result from unique clinical circumstances addressed by the operator. Generally, the devices of the invention are applied in a percutaneous heart valve access procedure where deep vascular access is desired. The procedure as described uses a femoral approach for the localization catheter and a left subclavian artery access for the deep vascular access needle entry. This procedure is followed by the discrete steps that are specific for the ultrasonic and fluoroscopic based embodiments. Key points in the procedure are illustrated in  FIGS. 14 through 20 .  FIG. 14  illustrates the aortic arch  1  and the branches emanating from the arch; the brachiocephalic artery  2 , the right subclavian  3 , the right common carotid  4 , the left common carotid artery  5 , and the left subclavian  6 . 
         [0044]    A localizing guide wire is introduced at the femoral artery and tracked through the aorta into the aortic arch  1  and then in to the left subclavian artery  6 . Referring to  FIG. 15 , the localizing guide catheter is tracked, under fluoroscopy, to a point where the locational element  11  is situated in a portion of the left subclavian artery  6  of sufficient diameter to support the introduction of the percutaneously delivered valve. The vessel diameter can be characterized by introduction of an appropriate contrast agent and monitored by the distal ultrasonic transducer when using the ultrasonic embodiment of the localizing guide wire  10 . 
         [0045]    Once an appropriate location has been identified, the diameter of the vessel can be verified by fluoroscopically using the appropriate contrast agent. When using the configuration of  FIG. 2  the contrast agent may be delivered via the lumen between the guide wire  12  and movable element  13 . Placement and adjustment of the localizing guide fixture is now performed. Placement and adjustment are complete when the guide path is aligned with localizing element  11  and the system is vacuum locked in place as described herein elsewhere. 
         [0046]    The deep access introducer needle  20  is then advanced through the center of the localizing guide fixture, through the patients intervening tissue, towards the locational element  11  on the localizing guide catheter as illustrated in  FIG. 16 . When present, transducers  22  on the distal end of the deep access introducer needles and comprised in the locational element  11  can be used to delineate proximity to the target site. The deep access introducer needle may comprise a relatively blunt tip which will tend to separate tissues at natural boundarys or may be sharp for piercing tissues. 
         [0047]    Once the distal end of the deep access introducer needle  20  has been placed within the target vessel at the target location, the localizing guide wire is fully or partially removed. The deep vascular access guide wire  19  is then placed as is illustrated in  FIG. 17 . Both the guidance system and the localizing guide wire are then completely removed from the operating field, leaving only the deep vascular access guide wire in place as is illustrated in  FIG. 18 . An introducer  50  along with its dilator is then delivered along the deep vascular access guide wire  19  as depicted in  FIG. 19 . After the introducer is introduced into the aorta at the target location and tracked to a position adjacent to the aortic valve, the dilator is removed as depicted in  FIG. 20 . The percutaneous heart valve replacement procedure then proceeds and the percutaneously delivered heart valve  60  is eventually placed as illustrated in  FIG. 21 . 
         [0048]    Referring to  FIGS. 10 ,  11  and  12 , the system may be used under Flouroscopic guide as follows. Localizing guide fixture  40  is placed over the target site, with appropriate tissue access, on the patient and the bottom face  44  of the base  43  is affixed to the patient by a suitable means. Suitable means may be adhesive, vacuum, clamping, or other. The fluoroscope is then aligned such that the target site, and locational element  11  is centered within the fluoroscopic field of view. The alignment will also be such that a normal to the image plane will align with the intended trajectory of the deep access introducer needle. 
         [0049]    The rotational stage  42  is then adjusted until the target rings are aligned as illustrated in  FIG. 11 . The locational element  11  may or may not be centered within the target rings, as illustrated in  FIG. 11 , at this time. If the locational element is not centered in the target rings as in  FIG. 12 , the rotational stage is adjusted appropriately and then the fluoroscope realigned to the new conformation. This can be an iterative process. Or alternatively the target rings may be aligned to correspond to the fluoroscopic conformation. Alignment is achieved when the locational element  11  is seen to be centered in target rings  23 , target ring images.  FIG. 11  illustrates an aligned guide while  FIG. 12  illustrates a slightly misaligned guide. 
         [0050]    Similarly, the system may be used under ultrasonic guide as follows. Localizing guide fixture  30  is placed over an ultrasonic coupling ring (not shown) over the target site, with appropriate tissue access, on the patient, and adjusted until the distance between each receiver leg  21  and the distal localizing transducer is equal. Under one transducer control protocol, these path lengths will be approximately equal when the time of flight for the signal arising from the distal localizing transducer on the localizing guide wire is equal for all receiver legs. Additional protocols will be obvious to those skilled in the art. 
         [0051]    The localizing guide fixture  30  may be locked in place at this point. Locking in place can be achieved either by affixing the guide fixture to the patient using adhesive or to the table upon which the patient is laying. Alternatively a system similar to that of system  40  includes 3 transducers at 120 degree centers on its bottom interface. The distance between each of these transducers and the distal localizing transducer is measured and converted into a set of settings for the rotational stage  42 , i.e. a rotational angle around the axis normal to the plane containing the three transducers comprised in or on the base and an angle relative to an axis normal to that plane. 
         [0052]    The deep access introducer needle  20  may also be placed ultrasonically by guidance over a location with appropriate tissue access to the target site as indicated by fluoroscopic image. The deep access introducer needle  20  is then directed and advanced towards the locational element on the localizing guide wire by the physician. The physician uses feedback indicative of the proximity of the deep access introducer needle&#39;s tip  22  to the locational element to adjust the path of the deep access introducer needle  20  as it is advanced to the target site. Feedback is provided by the interaction between the two. 
         [0053]    The deep access guide wire may be used with any of the present introducer sheath such as those manufactured by Sutura®, Vascular Solutions, Medtronics®, St. Jude®, Medafor® Inc., Cardiva Medical®, Access Closure™, or Abbot Vascular®. 
         [0054]      FIGS. 22 and 23  illustrate a needle guide fixture configured for remote adjustment. The central hub  211  is generally of any conventional shape from cylindrical to rectangular parallelepiped shape. The longer dimension is perforated as to accommodate the needle holder  203 . Both extremities of the longer dimension of the central hub are grooved  212  to accommodate radio opaque markers. The central hub  211  is connected to the middle frame  202  by means of a connecting inner shaft  205  in such a way that the central hub  211  can oscillate around the inner shaft  205 . Also connected to the inner shaft  205  is the inner gear  6  which is bonded to the central hub  211 . By actuating on the inner worm and screw shaft  207 , the inner gear  206  is actuated and the central hub  211  oscillates around the inner shaft  205 . 
         [0055]    In similar fashion the middle frame  202  is connected to the outer frame  201  by means of the outer shaft  208  and outer gear  209 . By actuating on the outer worm screw and shaft  210 , the outer gear  209  is actuated and the middle frame  202  oscillates in relation to the outer frame  201  and around the outer shaft  208 . 
         [0056]    The outer frame feet  213  are integral part of the outer frame  201 . By oscillating the middle frame  202  in relation to the outer frame  201 , and the central hub  211  in relation to the middle frame  202 , the operator changes the angle of the needle holder  203  in relation to the plane defined by the outer frame feet  213 . The radio opaque marker grooves  212  provide a means to align the central hub  211  and orient the needle holder  203  to a pre-positioned marker in the relevant anatomy. 
         [0057]    The procedure steps are as follows: The operator connects the assembly to the patient by means of the outer frame feet  213 . These may be equipped with magnets that would connect to magnets pre-placed on the skin of the patient. The fixture may alternatively be affixed with adhesives directly to the patient, with surgical tape, or to the operating table as with other guide fixtures described herein. A target radio opaque marker target (not shown) is placed in the relevant anatomy. This could be a radio opaque guidewire inserted through a distant vessel. The fluorsoscope is generally placed in line with the needle holder  3  and the radio-opaque target (not shown). The operator actuates the worm shafts  207  and  210  to oscillate or tilt the middle frame  202  and the central hub  211  in relation to the outer frame  201  and the patient. When alignment is achieved between the radio opaque markers  212  and radio opaque target (not shown), the operator inserts a needle (not shown) through the needle holder  203  and incrementally advances the needle into the patient until the needle approaches the radio opaque marker and proper positioning is verified. An additional guidewire (not shown) is inserted through the needle and into the same vessel as the radio opaque target. The needle and needle holder  203  are then removed leaving the guidewire in place. The cap  4  is advanced through the guidewire. The cap  204  provides means of facilitating the introduction of a dilator through the central opening of the central hub  211 . Whether the opening was previously occupied by the needle holder  203 . The dilator and introducer assembly (not shown) is introduced over the guidewire and throughout the central hub  211  and into the vessel in the patient.