Abstract:
A closure device, specifically an occlusion device for heart surgery procedures, e.g., transapical aortic valve implantation, comprises first and second disks ( 2, 3 ) having first and second enlarged diameter flange portions ( 25, 3 5) adapted to be placed proximate either end of an apical hole in a patient&#39;s heart wall, and first and second shoulder portions ( 20, 30 ) adapted to be placed within the apical hole near either end. A central waist portion ( 4 ) extends between the first and second disks ( 2, 3 ) along a center axis (A) of the device and is adapted to extend through the apical hole and interconnect the first and second disks ( 2, 3 ), while urging the disks ( 2, 3 ) toward one another when in the mounted condition.

Description:
[0001]    The present invention relates to an occlusion device for use in heart surgery procedures for the closure of punctures made in the cardiac wall. 
         [0002]    The apex of the heart refers to a lower portion of the heart, usually at the bottom part of the left ventricle. The thickness of the apex wall varies with each individual and may have a thickness of up to 18 mm. 
         [0003]    In minimally invasive cardiac surgery, such as heart valve replacement or left ventricular bypass, the delivery device must be passed into the interior of the heart via an artificial hole created in the heart wall, particularly in the apex region. Specifically, transapical aortic valve replacement (TAVR) surgery has developed rapidly in recent years and there is still no completely satisfactory way of closing the puncture artificially created for TAVR in the heart wall. 
       DESCRIPTION OF THE RELATED ART 
       [0004]    Apical closure devices and procedures have been advanced over the past years since the introduction of TAVR surgery, as illustrated for example in the review article “Left Ventricular Apical Access and Closure for TAVR”, by P. Vallabhajosyula and W. Y. Szeto, in  Cardiac Interventions Today  March/April 2013, page 45. The conventional closing procedures include purse-string suturing or a mattress suturing technique. 
         [0005]    A known closure device of Apica Cardiovascular Ltd. (ACS system) consists of a spiral coil designed to be rotated into the myocardium tissue about the apical hole. A closure cap is provided for sealing the coil, which provides a working port for future interventions if needed. However, it is still necessary to penetrate cardio tissue surrounding the apical hole and there is some risk of the closure cap being dislodged from the coil. 
         [0006]    U.S. Pat. No. 2012/0253386 A1 discloses another closure device comprising a main cylindrical body which can be deployed in a delivery device. Once deployed, prongs extend away from the axis of the main body and serve as anchors into the tissue surrounding the apical hole. The main body can then be collapsed to facilitate closure of the apical puncture. 
         [0007]    Another closure system is disclosed in U.S. 2012/0016411 A1. The closure apparatus comprises a tissue attachment portion arranged on the forward and rearward end of a cylindrical main body. The attachment portion includes hooks at both the distal end and proximal end of the cylindrical main body, which engage in the myocardium tissue around the hole for securement of the device. The cylindrical main body collapses toward the center of the hole and a sealing material is disposed within the center of the device to promote a sealing effect. 
         [0008]    All of the above methods and devices for closure of the apical hole have the common disadvantage of the requiring anchors and/or sutures which puncture the myocardium tissue surrounding the hole. 
         [0009]    The object of the present invention is to provide an improved apical occlusion device which requires little or no suturing or penetration of the myocardium and which is conveniently applied with a standard delivery device through the lumen of a catheter. 
       DISCLOSURE OF THE INVENTION 
       [0010]    According to the present invention an occlusion device is provided as defined in claim  1 . The device comprises a first disk having a first enlarged diameter flange portion adapted to be placed proximate an exterior end of an apical hole in a patient&#39;s heart wall and a first shoulder portion adapted to be placed within the apical hole near the exterior end. 
         [0011]    A second disk is provided having a second enlarged diameter flange portion adapted to be placed proximate an interior end of the apical hole in the patient&#39;s heart wall and a second shoulder portion adapted to be placed within the apical hole near the interior end. A central waist portion extends between the first and second disks along a center axis of the device, which is adapted to extend through the apical hole and connect the first and second disks, while urging the disks toward one another when in the mounted condition. 
         [0012]    The occlusion device is preferably made of metal wire mesh comprising a plurality of metal strands made of a shape metal material. Wires are preferably made of a nickel-titanium alloy. 
         [0013]    In a preferred embodiment, the first and second shoulder portions have respective inner faces which lie opposite one another in the direction of a center axis of the device, where each inner face is inwardly concaved to form a recess in the relaxed condition of the device. The central waist portion interconnects the inner faces of the first and second shoulder portions, both in the relaxed condition of the device and in the expanded condition when the device is mounted in the apical hole. When mounted, the inner faces are pulled axially apart and the recessed faces take on a flatter shape, while the first and second shoulder portions become separated. In this expanded, mounted condition, the inner flatter faces are separated axially from one another and lie substantially parallel to one another. 
         [0014]    The recessed inner faces of the first and second shoulder portions urge the double-disk device back toward the relaxed condition where the first and second shoulder portions are closest to one another. When deploying the device, the first and second shoulder portions are axially separated from one another, where the tension in the wire mesh of the inner faces is translated into a tension to bias the first and second disk portions back toward one another transmitted by the central waist portion. This structure allows the device to be flexed both axially and laterally such that it is capable of adjusting to the length and orientation of any given apical hole. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  shows a cross-sectional view of the occlusion device in the relaxed condition according to one embodiment of the invention; 
           [0016]      FIG. 2  shows a side view of the embodiment of  FIG. 1 , where the wire mesh structure becomes visible; 
           [0017]      FIG. 3  shows an end view of the embodiment of  FIGS. 1 and 2  taken along the center axis A of the device when looking in the direction from the smaller first disk to the larger second disk; 
           [0018]      FIG. 4  shows an embodiment by which the occlusion device is collapsed and located within the sheath of the delivery device; 
           [0019]      FIGS. 5 and 6  show two stages of a deployment procedure of the occluder in an apical hole of the human heart. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0020]    Further advantages of the present invention will become apparent from the discussion of preferred embodiments taken in conjunction with the drawings. 
         [0021]      FIGS. 1 and 2  illustrate a first embodiment of the present invention, where the occlusion device is depicted in the relaxed condition, where the metal mesh components made of shape memory alloy wires are at their relaxed position. A first disk  2  having an enlarged diameter flange portion  25 , shown on the left, is adapted to be placed proximate an exterior end of the apical hole in the patient&#39;s heart wall. The exterior end is the end of the hole facing the outside of the heart wall. The first disk  2  further comprises a first shoulder portion  20  which is adapted to be placed within the apical hole near the exterior end. 
         [0022]    Likewise, a second disk  3  has an enlarged diameter flange portion  35  which is adapted to be placed proximate an interior end of the apical hole, i.e. the end which is within the patient&#39;s heart. A second shoulder portion  30  is adapted to be placed within the hole near the interior end. With this construction, the enlarged diameter portions can engage opposing surfaces of the heart wall adjacent the apical hole. 
         [0023]    The occluder further comprises a central waist portion  4  which extends between the first and second disk portions  2 ,  3  along a center axis A of the device. The central waist portion  4  is adapted to extend through the apical hole and connect the first and second shoulder portions  20 ,  30  of the disks. 
         [0000]    As can be taken from  FIG. 1 , the first and second shoulder portions  20 ,  30  have respective inner faces  22 ,  32  which lie opposite one another in the direction of the center axis A. Each inner face  22 ,  32  is concaved inwardly within its corresponding shoulder portion  20 ,  30  by an angle β so as to form a recess in the relaxed condition as indicated. The angle β between the central waist  4  and the inner faces  22  and  32  may be adjusted so as to allow the axial extension of the occluder to increase or decrease to adapt to thickness of the heart wall. 
         [0024]    However, when the occluder is being deployed, the first and second disks are drawn apart from one another (see  FIGS. 5 and 6  and the discussion below), such that the central waist portion  4  pulls the recessed inner faces  22 ,  32  from the relaxed condition shown in  FIG. 1  to a mounted condition shown in  FIGS. 5 and 6  where the previously recessed inner faces now become substantially flat surfaces. With this arrangement, expanding the two disks to move apart axially during deployment is resisted by the mesh structure of the recessed inner faces  22 ,  32  of the shoulder portions. Or, starting from the expanded condition, the first and second shoulder portions  20 ,  30  are urged to return to the relaxed condition through the tensile force generated by the memory material of mesh structure of the inner faces  22 ,  32 . 
         [0025]    The central waist portion  4  comprises first and second side waist portions  21 ,  31  which are connected respectively to the inner faces  22 ,  32  of the first and second shoulder portions  20 ,  30  as shown in  FIG. 1 . The central waist portion  4  may be formed integrally as one piece with the entire occluder, which is fabricated in a heat shaping process of the shape memory mesh material. The waist portion  4  is highly contracted in comparison to the outer disk portions of the occluder and will typically have a diameter of about 2 mm. 
         [0026]    The overall length of the central waist portion  4  can be varied depending on the individual patient, but is at least 5 mm and generally in the range of 5 to 18 mm in length. Preferably the central waist portion is in the range of 5 to 12 mm. 
         [0027]    The side waist portions  21 ,  31  are provided as a generally tubular mesh sections which join integrally with the mesh of the inner faces  22 ,  32 . Preferably, each disk structure  2 ,  3  including the enlarged diameter flange portion  25 ,  35 , the shoulder portion  20 ,  30  and the respective part  21  or  31  of the waist portion are all formed of a single piece of wire mesh in a heat treatment for shape memory production. The flange portions  25 ,  35  will generally have a diameter in the range of 10 to 18 mm. The shoulder portions have a diameter in the range of 5 to 10 mm. 
         [0028]    The present design of the central waist portion in conjunction with the inner faces  22 ,  32  of the shoulder portions  20 ,  30  allow convenient adjustment of the length of the device. The construction allows a flexing of the opposing disks  2 ,  3  in both axial and lateral direction, so as to adjust to the length and orientation of the apical hole. At the same time, the disks are urged toward one another by tensioning arising from the mesh structure of the inner faces  22 ,  32 . 
         [0029]    As shown in  FIGS. 1 and 2 , an inner peripheral surface of the first enlarged diameter flange portion  25  is expanded to define a perimeter edge  23  which, when mounted, will contact an exterior surface of the heart wall adjacent the apical hole. Likewise, an inner peripheral surface of the second enlarged diameter flange portion  35  is expanded to define a perimeter edge  33  which, when mounted, will contact an interior surface of the heart wall adjacent the apical hole. 
         [0030]    The perimeter edge  33  of the second flange portion  35  is shaped differently, so as to match the shape of the heart wall from within, As shown in  FIGS. 5 and 6 , the heart wall near the apical hole has an acute inclination angle with respect to the center axis A of the device. Preferably, the associated perimeter edge  33  will have a matching inclination angle α with respect to the center axis A of about 65 degrees to 80 degrees. A typical inclination angle will be about 70 degrees. 
         [0031]    As illustrated in the embodiment of  FIG. 3 , the diameter of the first disk  2  for placement at the exterior surface is somewhat smaller that the diameter of the second disk  3  for placement on the interior heart wail. As an example the first disk  2  can have a diameter of 12 mm and the second disk  3  a diameter of 14 mm. These dimensions facilitate a better fit of the occluder when deployed, which is adapted to the anatomy of the inside and outside heart wall. 
         [0032]    In another preferred embodiment, the present occlusion device comprises at least one blood-flow inhibiting filter attached to each of the two disks  2 ,  3 . As shown in  FIG. 1 , the fabric filters  6 ,  8  can be placed adjacent to the surface of the enlarged diameter portions  25 ,  35 . Alternatively, filter fabrics  7  and  9  can be placed adjacent to the inner faces  22 ,  32  of the respective shoulder portions  20 ,  30 . Preferably, the blood flow inhibiting filter fabrics are secured by suturing the filter material to the wire mesh structure of the respective disks. In the preferred embodiment, each disk  2 ,  3  comprises two blood-flow restricting filters  6 ,  7  or  8 ,  9  attached to the respective disks  2  or  3 . 
         [0033]    In the present embodiment, the device comprises a clamp  1  adapted for releasable attachment to a delivery device, as shown for example in  FIGS. 1 and 4 . The clamp  1  can be provided with an internal or external threading for releasable attachment to the delivery device. Conventional devices provide clamps or connector portions on both ends of the double-disk occluder. The present design with only one clamp is patient friendly in terms of biocompatibility and can also aid endothelialization to a great extent. The collapsed configuration of the occluder as shown for example in  FIG. 4  is such that it can be delivered to an access site size of up to 34 Fr. 
         [0034]    The placement of the present apical occlusion device is similar to that used in surgery for ventricle septal defect (VSD) and atrial septal defect (ASD) These are common and familiar procedures for the surgeon and requires much less time than the mentioned devices and procedures of the prior art. Another advantage is that the present occluder allows for adjustment to the length of the apical hole without harm to the myocardium tissue. 
         [0035]    The deployment of the present occluder is accomplished with a delivery device comprising a sheath  11 . A pusher device  10  can be screw-connected to the clamp  1  of the occluder (see  FIG. 4 ) and the sheath  11  is brought into the target area. The pusher device pushes the interior disk  3  out of the sheath as illustrated in  FIG. 5 . The sheath is then further retracted until resistance is felt from the interior disk  3  when engaging the internal wall of the heart. The sheath  11  is then further retracted to deploy the second external disk  2  as shown in  FIG. 6 . Finally, the threaded clamp  1  is unscrewed from the pusher and the entire delivery device with sheath  11  can be withdrawn. 
         [0036]    The following is a clinical example of utilization of the present device in a TAVR procedure. 
         [0037]    The left ventricular apical thickness of the patient&#39;s heart was computed from a tomographic scan to be 6.5 mm. During the procedure with a standard anterolateral minithoracotomy, two reinforced purse-string sutures were performed at the apex to prevent major bleeding in case of occluder failure. 
         [0038]    The TA-TAVR procedure was performed, and a 23 mm Sapien XT valve was implanted. Following the procedure, the Ascendra delivery system was extracted and we inserted a 9 mm apex occluder under fluoroscopic guidance. The model occlude employed had a shoulder diameter of 7 mm. 
         [0039]    The distal part of the occluder was deployed in the LV and placed against the ventricular rim of the sheath  11 . Then, we performed a pullback of both the sheath  11  and the model occluder until we experienced a certain degree of resistance, meaning that the internal part of the occluder touched the apex opening. At that time, and without rapid cardiac pacing, we retrieved only the sheath  11  and thereby immediately deployed the external part of the occluder  2  with a good result. 
         [0040]    Only minor bleeding occurred that completely disappeared after protamine infusion. The occluder was still attached to the pusher  10  of the delivery system and still fully available in case of need. After 20 minutes of perfect functioning of the model occluder, it was disconnected from the delivery system and the purse-string sutures were tied only for safety reasons. Patient recovery was uneventful and without complications related to the occluder, and we restored anticoagulation treatment. After a 3-month follow-up period, the patients was asymptomatic and in good condition, 
         [0041]    As illustrated above, the application process of present occluder for closing an apical puncture is completely sutureless, and is performed in an easy and rapid manner, Less blood loss results and the healing time is shortened. Based on the success with the use of proven occluder delivery and application systems, the utilization of the present occluder system to the cardiac apex is safe and reliable. The special design of the adjustable waist and the single clamp construction make the occluder unique, efficient and safe to use.