Abstract:
Medical device for transcatheter heart valve repair comprising a grasping tweezer ( 1 ) and a plicating tweezer ( 2 ), said grasping tweezer ( 1 ) being adapted to grasp a leaflet rim ( 3 ) and said plicating tweezer ( 2 ) comprising two rotatable flaps ( 4,5 ) and a central shaft ( 6 ) around which said flaps ( 4,5 ) may rotate in a “butterfly manner”, in such a way that the plicating tweezer ( 2 ) may adopt a closed or an open configuration. The invention also relates to a method for using this medical device.

Description:
FIELD OF INVENTION 
       [0001]    The present invention relates to heart valve repair, in particular mitral valve repair. 
       STATE OF THE ART 
       [0002]    Mitral valve regurgitation (MR) is an abnormal, backwards flow of blood in the heart through the mitral valve. The mitral valve is one of 4 valves in the heart. It is located between the upper left heart chamber (left atrium) and lower left heart chamber (left ventricle). The mitral valve has 2 flaps, called leaflets, which open and close like a door with each heartbeat and normally let blood flow in just one direction through the heart. If the mitral valve does not close properly, some of the blood from the left ventricle is forced back up (regurgitated) into the left atrium instead of flowing out to the rest of the body. The added workload on the heart and increased blood pressure in the lungs may eventually cause problems. Although many diseases can damage the mitral valve and cause regurgitation mitral valve prolapse is the most frequent abnormality affecting 2.5% of the population. From that, 5 to 10% will develop severe regurgitation being the most common cause of mitral insufficiency in USA. Mitral valve prolapse occurs when the mitral valve leaflet tissue is deformed and elongated so that the leaflets do not come together normally leading to a MR. In severe cases, the left ventricle enlarges and functions less efficiently, the left atrium progressively enlarges, abnormal heart rhythms occur, and the blood pressure in the pulmonary artery increases leading to a pulmonary hypertension. Over time, these changes become irreversible as the signs and symptoms of heart failure develop. 
         [0003]    Ischemic MR is a complication of coronary heart disease; it primarily occurs in patients with a prior myocardial infarction (MI). MR may also occur with acute ischemia, a setting in which the MR typically resolves after the ischemia resolves. Following an MI, the MR is usually due to infarction with permanent damage to the papillary muscle or adjacent myocardium; in such patients, MR may become more severe with adverse remodeling of the left ventricle or subsequent ischemia. 
         [0004]    The need for treatment of MR depends upon the presence and severity of symptoms, the cause of the MR, and the presence of other underlying medical conditions. Medical and surgical therapies are available to treat people with MR. The treatment of choice for most people with severe chronic MR is surgical repair or replacement of the mitral valve. 
         [0005]    The mortality and long term results depends directly of the preoperative clinical condition. In patients with impaired left ventricular function, pulmonary hypertension (very common in mitral regurgitation) the surgical risk can be over 10%. The clinical relevance to find alternative approaches, which do not involve cutting the sternum is enormous. 
         [0006]    There is strong scientific evidences confirming that the repair instead replacement of the mitral valve is the treatment of choice mainly because its lower operative mortality and better long-term survival. Among the different techniques used to treat mitral prolapsed, the simplest and effective consists in resecting the prolapsed segment trough a triangular resection. This technique can be used in all types of prolapsed posterior leaflets an in many prolapsed anterior leaflets. This technique can be also used to treat ischemic MR. 
         [0007]    International patent application WO 2006/007576 discloses a system for percutaneous tissue repair. This device may also be used for mitral valve repair. The tissue is grasped, plicated and then sewed. 
         [0008]    With the system disclosed in WO 2006/007576 it is however not possible to carry out a triangular resection. 
       GENERAL DESCRIPTION OF THE INVENTION 
       [0009]    The present invention provides a new and original solution to repair a heart valve, in particular a mitral valve, in a percutaneous manner and, preferably, based on a “triangular resection” technique. 
         [0010]    The invention more precisely concerns a medical device and a surgical method for using said device as defined in the claims. 
         [0011]    The method according to the invention can be applied to the posterior leaflets (P 1 , P 2  and P 3 ) as well as the anterior leaflet. It can be also applied to treat prolapsed aortic valves, and prolapsed tricuspid valves. 
         [0012]    The method comprises the triangular plication of the prolapsed portion of the leaflet, the pinching of the plicated portion and, preferably, the resection of the excess of leaflet tissue. 
         [0013]    The method is based on the use of a single catheter (however two catheters could also be used from different access, namely transatrial, transapical etc.) that is inserted through a trans-septal access via the femoral vein or a peripheral vein or a transatrial access or a transapical access via a small thoracotomy incision. 
     
    
     
       DETAILED DESCRIPTION OF THE INVENTION 
         [0014]    To better disclose the invention, some illustrated but non-limiting examples are provided in the present chapter. 
           [0015]      FIG. 1  illustrates a first example of a device according to the invention 
           [0016]      FIG. 2  illustrates the plicating tweezer of  FIG. 1  in an open configuration and forming an angle of 25° with respect to the tweezer main axis. 
           [0017]      FIG. 3  illustrates the plicating tweezer of  FIG. 1  in an open configuration and forming an angle of 90° with respect to the tweezer main axis. 
           [0018]      FIG. 4  illustrates the plicating tweezer of  FIG. 1  in an closed configuration and forming an angle of 25° with respect to the tweezer main axis. 
           [0019]      FIGS. 5 a     01  to  5   a   16  show different steps of one surgical method according to the invention, taken from a first point of view. 
           [0020]      FIGS. 5 b     01  to  5   b   16  show different steps of the method illustrated in  FIGS. 5 a     01  to  5   a   16 , but taken from another point of view. 
       
    
    
     NUMERICAL REFERENCES USED IN THE FIGURES 
       [0000]    
       
           1  Grasping tweezer 
           2  Plicating tweezer 
           3  Tissue prolapsed portion or tissue rim 
           4  First flap 
           5  Second flap 
           6  Central shaft 
           7  First long segment of first flap 
           8  Second long segment of first flap 
           9  Short segment of first flap 
           10  First long segment of second flap 
           11  Second long segment of second flap 
           12  Short segment of second flap 
           13  Mesh 
           14  Catheter 
           15  Grasping tweezer main axis 
           16  Plicating tweezer main axis 
           17  Mitral valve 
           18  Plicating tweezer rotation axis 
       
     
         [0039]      FIG. 1  illustrates a mitral valve  17  having a leaflet containing a prolapsed portion  3 . 
         [0040]    The device comprises a tissue grasping tweezer  1  and a plicating tweezer  2 , both tweezers  1 , 2  are moved to the operating field within a single catheter  14 . 
         [0041]    The grasping tweezer  1  forms a variable angle with respect to the grasping tweezer main axis  15 . 
         [0042]    The plicating tweezer  2  is made of a central shaft  6  around which two triangular shaped flaps  4 , 5  can rotate. Each flap  4 , 5  comprises two main segments  7 , 8 , 10 , 11  which, together with the central shaft  6 , form a triangular element. All the segments  7 - 12  are furthermore covered by a mesh  13 . 
         [0043]    In addition, or in replacement to the mesh  13 , the segments  7 - 12  may be covered by a metallic layer, a synthetic layer or a biological tissue. 
         [0044]    The catheter  14  is inserted at the level of the diseased valve  17  in correspondence of the prolapsed portion of the leaflet  3  ( FIG. 5  a 01 ,  FIG. 5  a 02 ,  FIG. 5  b 01  and  FIG. 5  b 02 ). The grasping tweezer  1  is extracted from the catheter  14  and under fluoroscopy and Echo 3D guidance is remotely actuated by the operator in a way to grab the central portion of the prolapsed portion  3  for an extension going from the free edge towards the mitral annulus (typically a length ranging from 0.5 to 2.5 cm) ( FIGS. 5  a 03  to a 08  and  FIGS. 5  b 03  to b 08 ). 
         [0045]    The plicating tweezer  2  is then extracted from the catheter  14 , rotated around an axis  18 , opened and placed parallel to an ideal valve plan, in touch with the prolapsed portion  3  ( FIGS. 5  a 09  to a 12  and  FIGS. 5  b 09  to b 12 ). 
         [0046]    When the device is stable the grasping tweezer  1 , still grabbing the prolapsed portion  3 , is moved slightly upward creating a tensioned flap corresponding to the prolapsed portion  3 . In this setting the plicating tweezer  2  is closed, over the grasping tweezer  1 , to plicate and pinching triangular shaped prolapsed portion  3  ( FIG. 5  a 13  and  FIG. 5  b 13 ). 
         [0047]    At this stage, before to proceed cutting out the prolapsed portion  3 , the online control with an Echo 2D or better 3D may confirm that the residual regurgitation is negligible or eliminated. 
         [0048]    If the hemodynamic conditions of the mitral valve  17  are considered suboptimal the procedure can be repeated retracting the plicating tweezer  2  and using the grasping tweezer  1  to pinch more or less leaflet tissue or to slightly change position to better pinch the prolapsed portion  3 . When the grasping tweezer  1  pinches the leaflet again the procedure can be allover repeated. 
         [0049]    The plicating tweezer  2 , when open, has a polygonal shape ( FIG. 5  a 11 ) made by a plurality of segments  6 - 12  which substantially form two triangular frames hinged at level of the central shaft  6 . More precisely, each substantial triangular frame is formed by three long segments  6 - 8  &amp;  6 , 10 , 11  (that form the general triangular shape) and one short segment  9 , 12 . The shape and dimensions of the triangular frames can be variable in order to treat a different degree of leaflet prolapse. A thin mesh of tissue  13  made of biological, polymeric or metallic material covers the triangular frames. The purpose of the mesh coverage is to avoid the accidental embolization of blood clots, calcific fragments or leaflet&#39;s portions during the transcatheter mitral repair procedure. 
         [0050]    Once a satisfactory result is reached the arms of the plicating tweezer  2  are closed over the folded prolapsed leaflet  3 . The flap sides  8 , 11  of the plicating tweezer  2  which are in contact with the tissue can deliver a series of staples, stitches, thermal treatment, radiofrequency, cryo-therapy treatment or any other system to fix together the two portions of the prolapsed leaflet  3 . In alternative constructive solution the portions of the leaflet could be glued together by injecting glue, polymers or any other biocompatible glue material through the arms of the tweezer ( FIG. 5  a 12 , a 13  and  FIG. 5  b 12 , b 13 ). 
         [0051]    The pinched leaflet portion will be on the atrial side however the repair procedure could be also performed upside down in a way that the pinched portion of the leaflet is oriented toward the ventricle and placed below the valve plane. This is useful especially, but not exclusively, in patients with complete flail (complete chordae rupture). 
         [0052]    The procedure can be completed with the resection of the plicated and pinched portion in both the above-described procedural situations. The flap sides  8 , 11  of the plicating tweezer  2  which are in contact with the tissue are equipped with a system making a triple function. One is aimed at locking the base line of the plicated, triangular shape, portion of the leaflet, the second one to deliver staples or stitches and the third one at cutting the plicated leaflet portion just above the suture line ( FIG. 5  a 14   e    FIG. 5  b 14 ). 
         [0053]    At the end of the procedure the arms of the plicating tweezer  2  are maintained closed over the leaflet tissue fragment and retrieved into the catheter together with the first tweezer ( FIG. 5  a 15   e  b 15 ). 
         [0054]    The procedure is completed when the entire catheter is fully retrieved out of the patient ( FIG. 5  a 16   e  b 16 ). 
         [0055]    Both tweezers  1 , 2  can be realized with different materials including various metals alloys such as Nitinol, Stainless steel, Cobalt-Chromium or plastic polymers. The articulation and the remote control of the tweezers can be realized adopting several mechanical, pneumatic, hydraulic or electrical solutions also using memory shape alloys such as the Nitinol. The arms of the tweezers  1 , 2  can be straight or curved with different length depending the final adopted solution. 
         [0056]    One way to perform the “plication” is achieved with a surgical stapler together with surgical staples. The staple line may be straight, curved or circular. The instruments may be used in either open or thoracoscopic surgery or full transcatheter, and different instruments can be used for each application. Transcatheter staplers must be longer, thinner, and may be articulated to allow for access from the peripheral veins or arteries. 
         [0057]    Some device can incorporate a knife, to complete excision of the prolapsed segment of the mitral leaflet and anastomosis in a single operation. 
         [0058]    The surgical staples can be made of titanium, namely a material that induces less reaction with the immune system and, being non-ferrous, does not interfere significantly with MRI scanners. Synthetic absorbable or non-absorbable materials could also be used. 
         [0059]    The invention is of course not limited to the device presented in the previous example. The device according to the invention may be used for plication only, i.e. without removal of the prolapsed part of the leaflet.