Abstract:
A mitral cerclage annuloplasty apparatus comprises a tissue protective device and a cap device having a cerclage suture disposed within a first protective tube and a second protective tube, the proximal portions of the two tubes being attached side-by-side longitudinally to define a stem portion, the distal portions of the two tubes being separated thereafter, and a cap device that covers the stem portion wherein the stem portion and the cap device interlock, so that once the cerclage suture is knotted on the outer surface of the cap device, cap device can be pulled outwardly to enhance and maintain tension applied to the mitral annulus thus successfully treating the mitral regurgitation.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of prior application Ser. No. 12/631,803, filed Dec. 4, 2009 and claims the benefit of a foreign priority of Korean Patent Application No. 10-2011-0080392, filed Aug. 12, 2011, which is incorporated herein in its entirety. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    The present disclosure relates to mitral valve cerclage annuloplasty devices and techniques in which during the final stage of cerclage annuloplasty procedure, a proper tension is applied and maintained safely on the cerclage sutures then firmly secured by using a knot tightening and securing device. 
       BACKGROUND OF THE INVENTION 
       [0003]    The heart is the center of human circulatory system that pumps blood through our body. It is a muscle that pumps the blood only in one direction. In order for the heart to effectively maintain this unidirectional flow of blood, it must have properly functional valves that prevent back flow through its system, or regurgitation. The heart is divided into four chambers, right and left atria, and right and left ventricles. The four chambers are connected to the aorta, the inferior and superior vena cava, the pulmonary artery, and the pulmonary veins. 
         [0004]    The mitral valve (“MV”) separates the left atrium from the left ventricle while the tricuspid valve (TV) separates the right atrium from the right ventricle. The aortic valve (“AV”) is located between the left ventricle and the aorta while the pulmonary valve (“PV”) is located between the right ventricle and the pulmonary artery. 
         [0005]    Generally, valves should open and close completely with every heart beat or contraction. Incomplete opening and closing of the valves cause improper flow of blood, either back flow and/or reduced. These are valvular diseases. The valvular diseases are divided into two categories, regurgitation and stenosis. Regurgitation is a failure of valve to close completely allowing back flow of blood. Stenosis is a failure of valve to open completely reducing the flow of blood. Both can increase stress on the heart. 
         [0006]    Mitral valve regurgitation (“MVR”) is a valvular disease in which an incomplete closure of the MV results in a back flow of blood. Such back flow of blood increases stress on the heart which can decrease the heart function and eventually lead to an irregular heart beat or a cardiac arrhythmia. 
         [0007]    Traditional treatment of a worsening MVR requires an open heart surgery with a sternotomy or a thoracotomy then opening the heart itself following a cardiopulmonary bypass and a cardiac arrest. Once the chest is opened and access to the heart is gained, the MV is either repaired or replaced with an artificial valve. Although very effective, this open-heart procedure is an invasive high-risk surgery accompanied by a substantial morbidity and mortality. The mortality due to the surgery itself can be as high as 5%. Hence, the procedure is often reserved only to those patients with severe symptomatic MVR. 
         [0008]    This high morbidity rate of the open heart surgery has recently lead to an increase in researches to develop a safer and relatively more simple alternative procedures to repair the MVR using a cardiac catheterization technique. Along this international effort to find a safer alternative procedure, recently, this inventor presented internationally his thesis regarding “the mitral valve cerclage coronary sinus annuloplasty” and demonstrated outstanding result of the MVR treatment involving the application of a circular pressure around the mitral annulus (MA). This thesis has been filed through PCT as an international patent application (application number: PCT/US2007/023836), and is currently published with the international patent office (publication number: WO2008/060553), which are incorporated herein in their entirety. 
         [0009]    The aforementioned thesis and published patent applications disclosed the mitral valve cerclage annuloplasty procedure. Briefly explained, a catheter is placed at the coronary sinus after accessing the right atrium through the jugular vein, and then a cerclage suture is passed through the proximal septal vein. This cerclage suture can easily pass through the right ventricular outflow tract (“RVOT”). The inventor defines this technique as “the simple mitral cerclage annuloplasty.” Then the cerclage suture can be easily pulled into the right atrium thus placing the cerclage suture circumferentially around the MA. Once positioned, tension is applied to the cerclage suture and tightens the mitral valve. This brings together the two leaflets of the MV so that they are approximated to each other thus decreasing the size of its incomplete closure. This procedure can obtain a very similar result when compared to the result of a conventional surgery that directly tightens the mitral annulus, and can immediately reduce the regurgitation effectively treating a MVR. 
         [0010]    However, there were technical problems in the previous thesis and patent applications that needed to be solved. First, there is a need to have a tension locking device that can apply a proper tension and maintain it securely during the procedure. Second, since this tension is maintained with a very fine cerclage suture i.e., 0.014 inch nylon cerclage used in the researches (although thickness may change), it can cause damages on the cardiac tissues where the suture contacts and exerts its pressure. 
         [0011]    To address these technical problems, this inventor has filed Korean patent application (application number 2009-0080708) on Aug. 8, 2008, titled “the Mitral Valve Cerclage Annuloplasty Apparatus” that includes the coronary sinus and the tricuspid valve protection device, and a knot delivery device. 
         [0012]    This patent application has also been filed with the U.S. Patent and Trademark Office and patent offices in other countries. 
         [0013]    In the aforementioned patent application, the cardiac tissue is protected from the damage caused by the direct suture contact using a tissue protective device comprising a coronary sinus tube (“CS tube”) and a tricuspid valve tube (“TV tube”). Further, a knot delivery device is used to place a knot at the end of the tissue protective device to complete the procedure. 
         [0014]    However, even though the knot was placed at the end of the tissue protective device, a slack of suture remained between the end of the tissue protective device and the knot, so that the proper tension needed on the cerclage was difficult to obtain initially, and due to the remaining excess suture, the cerclage became loose. 
         [0015]    In the aforementioned mitral valve cerclage annuloplasty procedure, when the cerclage suture became loose, the tension on the suture decreased thereby reducing its circumferential pressure applied around the MA resulting in a decreased effectiveness of the MVR treatment. This invention is intended to provide a viable solutions to overcome these problems. 
       SUMMARY OF THE INVENTION 
       [0016]    The objective of this invention is to overcome the shortcomings of the aforementioned mitral valve cerclage annuloplasty apparatus by providing a device that can maintain a constant proper tension without creating a laxity on the cerclage suture thereby applying and maintaining a proper circumferential pressure around the MA and thus, increasing the effectiveness and the success of the mitral valve cerclage annuloplasty. 
         [0017]    This invention achieves the aforementioned objectives by using a simple, easy to use devices described here that can initiate a proper knot placement and maintain its proper tension on the cerclage suture continuously. 
         [0018]    Generally, to achieve its objective and overcome the shortcomings of the aforemetioned mitral valve cerclage annuloplasty apparatus, the current invention comprises a coronary sinus protective device  22 , a tricuspid valve and ventricular wall protective device  24 , a distal coronary sinus tissue protective tube, and a distal tricuspid valve protective tube that connects and becomes fixed, and a tissue protective device  20  with a built-in locking bumps  28  ingrained on the outside of the stem portion  26 . 
         [0019]    This invention further comprises a hollow cap  30  that fits over the tissue protective device  20  with an open proximal end, a closed distal end  31  with two or smaller openings  32  that allows passing of the cerclage sutures, and a built-in locking ridges  35  ingrained on the inside of the hollow cap  30  that interlocks with the stem-portion locking-bumps  28  of the tissue protective device  20 . 
         [0020]    The stem-portion locking-bumps  28  of the tissue protective device  20  and the cap locking ridges  35  interlock in such a manner that only allows the lengthening of the tissue protective device  20  and the hollow cap  30 , and prevents shortening of the tissue protective device  20  and the hollow cap  30 . 
         [0021]    According to the current invention, a ring-hook  34  that allows a suture to be passed through is located at the distal end of the hollow cap  30 . 
         [0022]    In a first embodiment, the stem-portion locking-bumps  28  of the tissue protective device  20  and the cap locking ridges  35  are in a shape of a saw-tooth. 
         [0023]    In a second embodiment, the stem-portion locking-bumps  28  of the tissue protective device  20  is in a shape of a saw-tooth, and the cap locking ridges  35  are formed by equally spaced slits corresponding to the stem-portion locking-bumps  28 . 
         [0024]    In a third embodiment, the hollow cap  30  comprises a cap body  38  and a cap lid  36  such that a neck  36   a  of the cap lid inserts into the cap body  38 . 
         [0025]    In a fourth embodiment, the inside of the cap body  38  and the out side of the neck of the cap lid  36   a  is in the shape of a screw such that cap can be screwed into the cap body. 
         [0026]    In a fifth embodiment, the stem-portion locking-bumps  28  of the tissue protective device  20  can on the two sides of the stem portion rather than surrounding the entire stem circumferentially. 
         [0027]    As described above, the current invention improves the mitral valve cerclage annuloplasty apparatus by adding the hollow cap  30  to the tissue protective device  20 . The hollow cap  30  holds the cerclage suture knot in place while persistently maintaining a proper tension. When a persistent proper tension on the cerclage suture is maintained without laxity, a proper circumferential pressure around the MA can be sustained continuously thus, increasing the effectiveness and the success of the mitral valve cerclage annuloplasty. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  and  FIG. 2  show the mitral valve cerclage annuloplasty apparatus comprising a tissue protective device and a hollow cap.  FIG. 1  shows the tissue protective device and the hollow cap before the cap is placed onto the tissue protective device, and  FIG. 2  shows the hollow cap fitted onto the tissue protective device. 
           [0029]      FIG. 3  and  FIG. 5  show the mitral valve cerclage annuloplasty apparatus in operation with the cerclage suture.  FIG. 3  shows the cerclage suture knot placed outside the hollow cap.  FIG. 4  shows the hollow cap being pulled outwardly from the stem portion of the tissue protective device while the cerclage suture knot is caught and supported by the closed distal end of the hollow cap.  FIG. 5  shows cutting and removing of the excess cerclage suture distal to the knot, and removing the cap pulling suture. 
           [0030]      FIG. 6  shows the process in which the tissue protective device and the hollow cap become engaged in a first embodiment of the mitral valve cerclage annuloplasty apparatus. 
           [0031]      FIG. 7  shows a second embodiment of the mitral valve cerclage annuloplasty apparatus with a different cap configuration. 
           [0032]      FIG. 8  shows a third embodiment of the mitral valve cerclage annuloplasty apparatus with another cap configuration. 
           [0033]      FIG. 9  shows a different configuration of the locking-bumps on the stem portion of the tissue protective device and the locking ridges in the hollow cap of the mitral valve cerclage annuloplasty apparatus. 
           [0034]      FIG. 10  shows another configuration of locking-bumps on the stem portion of the tissue protective device and the locking ridges in the hollow cap of the mitral valve cerclage annuloplasty apparatus. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0035]    The detailed disclosure of the mitral valve cerclage annuloplasty apparatus (MVA) comprising a tissue protective device and a hollow cap will be discussed. 
         [0036]    According to the current invention,  FIGS. 1-2  shows the mitral valve cerclage annuloplasty apparatus (MVA) comprising the tissue protective device  20  and the hollow cap  30 .  FIG. 1  shows the tissue protective device  20  and the hollow cap  30  before they are engaged, and  FIG. 2  shows the tissue protective device  20  and the hollow cap  30  in an engaged state. The tissue protective device  20  in the current invention differs from the inventor&#39;s previous patent application (#2009-0080708) in that the stem portion of the tissue protective device  20  has a built-in locking bumps  28  ingrained on its outer surface. 
         [0037]    Generally, in a conventional MVA techniques cause tissue damage or erosion to the coronary sinus (“CS”), the tricuspid valve (“TV”) and the intraventricular septum (“IVS”) from a direct cerclage suture to tissue contact. These critical structures can be protected from damage by using the tissue protective device  20  comprising hollow tubes that allows passing of the cerclage suture preventing the direct contact of the suture onto the CS, the TV and the IVS tissues. Accordingly, the tissue protective device  20  comprises of a coronary sinus tube  22  (“CS tube”) that protects the CS tissue, a tricuspid valve tube  24  (“TV tube”) that protects the TV tissue and the IVS tissue, and a stem portion  26  with locking bumps  28  ingrained on its outer surface. 
         [0038]    The inside of the cap  30  is hollow to allow insertion of the stem portion  26  of the tissue protective device  20 , and it has an ingrained locking ridges  35  on its inside that interlocks with the locking bumps  28  ingrained on the outer surface of the stem portion  26 . 
         [0039]    The locking bumps  28  on the stem portion  26  and the locking ridges  35  ingrained on the inside of the hollow cap  30  are made so that they interlock in a way that allows only the outward movement of the hollow cap  30  while preventing the inward movement of the hollow cap  30 . Thus, during the procedure, once a knot is made with the cerclage suture, the hollow cap  30  can be advanced outwardly to remove any laxity in the cerclage suture and then continuously maintain a proper tension on the cerclage suture. 
         [0040]    To maintain the proper tension, the preferred shape of the stem-portion locking bumps  28  and the cap locking ridges  35  is that of a saw-tooth. 
         [0041]    The hollow cap  30  comprises a closed distal end  31  with two or more small openings  32 . The purpose of the closed distal end  31  is to support a cerclage-suture knot in place when the cap  30  is moved outwardly, and the purpose of the small openings  32  is to allow passage of the cerclage suture. 
         [0042]    Further, on the outer surface of the closed distal end  31  of the hollow cap  30  comprises a ring hook  34  for attaching a cap-pulling suture used to pull the cap  30  outwardly. 
         [0043]      FIGS. 3-5  show operations of the MVA.  FIG. 3  shows the cerclage-suture knot  12  made with a cerclage suture  10 .  FIG. 4  shows the cerclage-suture knot  12  supported by the closed distal end  31  as the cap  30  is moved outwardly using the cap-pulling suture  15 .  FIG. 5  shows the cerclage-suture knot  12  after the excess cerclage suture has been cut distal to the knot and removed, and removing of the cap-pulling suture  15 . 
         [0044]    In the cerclage annuloplasty procedure, once a proper circumferential pressure is applied onto the mitral valve with the cerclage suture  10  using the MVA of the current invention, a knot delivery device introduced by the inventor in his previous patent application (#2009-008070808) can be used to make the cerclage-suture knot  12 . In this state as shown in  FIG. 3 , because the cerclage-suture knot  12  is not tight against the hollow cap  30 , it is difficult to maintain the proper tension on the cerclage suture  10 . 
         [0045]    The cap-pulling suture  15  is first looped around the ring hook  34  of the hollow cap  30 , then it is extended distally to outside the body. The purpose of the cap-pulling suture  15  is to pull the hollow cap  30  outwardly. 
         [0046]    Once the cerclage-suture knot  12  is made as shown in  FIG. 4 , when the cap-pulling suture  15  looped around the ring hook  34  is pulled from outside the body, as shown in  FIG. 5 , the hollow cap  30  will move outwardly. Since the cerclage-suture knot  12  is caught and supported by the closed distal end  31  of the hollow cap  30 , the cap-pulling suture  15  can pull the hollow cap  30  moving it outwardly until the proper tension on the cerclage suture is obtained. As the hollow cap  30  is pulled outwardly, the locking bumps  28  on the stem-potion of the tissue protective device  20  and the cap locking ridges  35  interlock in a way such that they only allow outward movement of the hollow cap  30  and prevent its inward movement. Hence, even if the cap-pulling suture  15  no longer pulls on the cap outwardly, the hollow cap  30  will not advance inward. 
         [0047]    As shown in  FIG. 4 , when the proper tension is obtained on the cerclage suture  10  by moving the hollow cap  30  outwardly, since the cerclage-suture knot  12  is caught and supported by the closed distal end  31 , the circumferential pressure applied around the mitral annulus can be maintained constantly. Hence, the MVR of a patient is eliminated increasing the effectiveness and the success of the mitral valve cerclage annuloplasty. 
         [0048]    As shown in  FIG. 5 , after cutting the cerclage suture  10  at a certain distance from the cerclage-suture knot  12  using a cutter (not illustrated here), the remaining excess cerclage suture can be taken out of the body, and the cap-pulling suture  15  can also be pulled out of the body. Hence, the mitral valve cerclage annuloplasty procedure is completed. 
         [0049]    According to the current mitral valve cerclage annuloplasty apparatus, before starting the mitral valve annuloplasty procedure, the tissue protective device  20  must be inserted fully into the hollow cap  30 . Due to the way in which the stem-portion locking bumps  28  of the tissue protective device  20  and the cap locking ridges  35  interlock, it can be difficult to engage the tissue protective device  20  fully into the hollow cap  30 . 
         [0050]    There are various ways to fully engage the hollow cap  30  with the tissue protective device  20 .  FIG. 6  shows one of these methods where an expander  50  is used to help engage the hollow cap  30  with the tissue protective device  20 . 
         [0051]    The expander  50  is made in an L-shape with a handle bar  50   a  and an expander bar  50   b.  The expander bar  50   b  is inserted into the hollow cap  30 , and the handle bar  50   a  is used to apply force needed to expand the hollow cap  30 . The expander  50  is used to expand the inside space of the hollow cap  30  to allow easier entry of the tissue protective device  20 . The hollow cap  30  can be made of a soft or a silk-like material. If the hollow cap  30  is made of a soft material, the expander  50  can be used to expand the inside space of the hollow cap  30  so that the tissue protective device  20  can be inserted into the hollow cap  30 . 
         [0052]    Three or more expanders  50  are used together to expand the inside space of the hollow cap  30  so that when they are pulled in opposing directions, the inside space of the hollow cap  30  is expanded to allow easier entry of the tissue protective device  20 . 
         [0053]    Once the tissue protective device  20  is fully inserted into the hollow cap  30 , the expanders  50  return to their original position and are removed from the hollow cap  30  thereby achieving their purpose of helping engage the tissue protective device  20  with the hollow cap  30 . 
         [0054]    The expanders  50  can be installed on an expander device (not displayed) which can be operated using a motor or cylinder (not displayed). The expander device is used to operate the expanders  50  so that the expanders can expand or reduce the hollow cap  30 . 
         [0055]      FIG. 7  shows another method of inserting the tissue protective device  20  into the hollow cap  30  where the hollow cap  30  is further divided into a cap body  38  and a cap lid  36 . The cap body  38  and the cap lid  36  can be joined or separated. 
         [0056]    As shown in  FIG. 7 , the cap body  38  and the cap lid  36  of hollow cap  30  are configured so that they can be joined or separated. The distal end of the cap lid  36  is formed as a cap-lid neck  36   a  so that it can be inserted into the cap body  38 . In other words, when the cap lid  36  is separated from the cap body  38 , the cap-lid neck  36   a  can be inserted into the cap body  38  so that the cap lid  36  and the cap body  38  can be become one. 
         [0057]    First, the cap body  38  is separated from the cap lid  36 . Then the two distal tubes of the tissue protective device  20  (the coronary sinus tube  22  and the tricuspid valve tube  24 ) are inserted into the cap body  38  through its upper portion. The tissue protective device  20  is then pulled through the cap body  38  until the stem portion of the tissue protective device is covered by the cap body  38 . Then the cap lid  36  is inserted into the cap body  38  thus uniting the tissue protective device  20  and the hollow cap  30 . An adhesive can be used to firmly secure the cap lid  38  to the cap body  36 . 
         [0058]      FIG. 8  shows another embodiment of the hollow cap  30  with its detachable cap lid  36  and the cap body  38 . The outer surface of the cap lid neck  36   a  has screw-like cap-lid thread  36   b,  and the inside of the cap body  38  has its corresponding cap-body receiving thread  38   b . Hence, the cap lid  36  can be screwed into the lid body  38 . 
         [0059]      FIG. 9  shows another embodiment of the mitral valve cerclage annuloplasty apparatus with a different distribution of the stem-portion locking bumps  28  of the tissue protective device  20 , and the cap locking ridges  35 . 
         [0060]      FIG. 9  shows the locking bumps  28  ingrained on a part of the stem portion of the tissue protective device  20  rather than over the entire length of the stem portion. Specifically, the locking bumps  28  can be ingrained only on the sides of the stem portion of the tissue protective device  20 . As shown in  FIG. 9 , the cap locking ridges  35  can also be ingrained on part of the hollow cap  30  rather than on the entire inside surface. The purpose of ingraining the locking bumps  28  only the sides of the stem portion of the tissue protective device is to facilitate easier flow of the blood. 
         [0061]      FIG. 10  shows another embodiment of the mitral valve cerclage annuloplasty apparatus with a different shape of the cap locking ridges  35 .  FIG. 9  shows the cap locking ridges  35  inside the hollow cap  30  made of equally spaced open slits  39 . 
         [0062]    While the invention has been described in terms of specific embodiments, it is apparent that other forms could be adopted by one skilled in the art. Accordingly, it should be understood that the invention is not limited to the specific embodiments illustrated in the Figures. It should also be understood that the phraseology and terminology employed above are for the purpose of disclosing the illustrated embodiments, and do not necessarily serve as limitations to the scope of the invention.