Abstract:
An assembly for effecting the condition of a mitral valve of a heart includes a mitral valve therapy device, a guide wire, and a guide tube. The mitral valve therapy device is configured to reshape the mitral valve annulus of the heart when placed within the coronary sinus adjacent the mitral valve annulus. The guide wire is configured to be fed into the coronary sinus of the heart adjacent the mitral valve annulus. The guide tube has a distal end, a proximal end, and a lumen extending between the distal end and the proximal end. The guide tube further includes a side port, intermediate the distal and proximal ends which communicates with the lumen. This permits the guide tube to be slidingly received on the guide wire with the guide wire extending from the distal end, through the lumen, and out the side port. In use, the guide tube is slid along the guide wire into the coronary sinus. The mitral valve therapy device is then delivered by the guide tube into the coronary sinus adjacent the mitral valve annulus.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention generally relates to a system and method for treating a deformed heart valve. The present invention more particularly relates to a system and method for delivering a mitral valve therapy device into the coronary sinus of a heart to treat mitral valve dilation.  
         BACKGROUND OF THE INVENTION  
         [0002]    The human heart generally includes four valves. Of these valves, a most critical one is known as the mitral valve. The mitral valve is located in the left atrial ventricular opening between the left atrium and left ventricle. The mitral valve is intended to prevent regurgitation of blood from the left ventricle into the left atrium when the left ventricle contracts. In preventing blood regurgitation the mitral valve must be able to withstand considerable back pressure as the left ventricle contracts.  
           [0003]    The valve cusps of the mitral valve are anchored to muscular wall of the heart by delicate but strong fibrous cords in order to support the cusps during left ventricular contraction. In a healthy mitral valve, the geometry of the mitral valve ensures that the cusps overlie each other to preclude regurgitation of the blood during left ventricular contraction.  
           [0004]    The normal functioning of the mitral valve in preventing regurgitation can be impaired by dilated cardiomyopathy caused by disease or certain natural defects. For example, certain diseases may cause dilation of the mitral valve annulus. This can result in deformation of the mitral valve geometry to cause ineffective closure of the mitral valve during left ventricular contraction. Such ineffective closure results in leakage through the mitral valve and regurgitation. Diseases such as bacterial inflammations of the heart or heart failure can cause the aforementioned distortion or dilation of the mitral valve annulus. Needless to say, mitral valve regurgitation must not go uncorrected.  
           [0005]    One method of repairing a mitral valve having impaired function is to completely replace the valve. This method has been found to be particularly suitable for replacing a mitral valve when one of the cusps has been severely damaged or deformed. While the replacement of the entire valve eliminates the immediate problem associated with a dilated mitral valve annulus, presently available prosthetic heart valves do not possess the same durability as natural heart valves.  
           [0006]    Various other surgical procedures have been developed to correct the deformation of the mitral valve annulus and thus retain the intact natural heart valve function. These surgical techniques involve repairing the shape of the dilated or deformed valve annulus. Such techniques, generally known as annuloplasty, require surgically restricting the valve annulus to minimize dilation. Here, a prosthesis is typically sutured about the base of the valve leaflets to reshape the valve annulus and restrict the movement of the valve annulus during the opening and closing of the mitral valve.  
           [0007]    Many different types of prostheses have been developed for use in such surgery. In general, prostheses are annular or partially annular shaped members which fit about the base of the valve annulus. The annular or partially annular shaped members may be formed from a rigid material, such as a metal, or from a flexible material.  
           [0008]    While the prior art methods mentioned above have been able to achieve some success in treating mitral regurgitation, they have not been without problems and potential adverse consequences. For example, these procedures require open heart surgery. Such procedures are expensive, are extremely invasive requiring considerable recovery time, and pose the concomitant mortality risks associated with such procedures. Moreover, such open heart procedures are particularly stressful on patients with a comprised cardiac condition. Given these factors, such procedures are often reserved as a last resort and hence are employed late in the mitral regurgitation progression. Further, the effectiveness of such procedures is difficult to assess during the procedure and may not be known until a much later time. Hence, the ability to make adjustments to or changes in the prostheses to obtain optimum effectiveness is extremely limited. Later corrections, if made at all, require still another open heart surgery.  
           [0009]    An improved therapy to treat mitral regurgitation without resorting to open heart surgery has recently been proposed. This is rendered possible by the realization that the coronary sinus of a heart is near to and at least partially encircles the mitral valve annulus and then extends into a venous system including the great cardiac vein. As used herein, the term “coronary sinus” is meant to refer to not only the coronary sinus itself but in addition, the venous system associated with the coronary sinus including the great cardiac vein. The therapy contemplates the use of a device introduced into the coronary sinus to reshape and advantageously effect the geometry of the mitral valve annulus.  
           [0010]    The device includes a resilient member having a cross sectional dimension for being received within the coronary sinus of the heart and a longitudinal dimension having an unstressed arched configuration when placed in the coronary sinus. The device partially encircles and exerts an inward pressure on the mitral valve. The inward pressure constricts the mitral valve annulus, or at least a portion of it, to essentially restore the mitral valve geometry. This promotes effective valve sealing action and eliminates mitral regurgitation.  
           [0011]    The device may be implanted in the coronary sinus using only percutaneous techniques similar to the techniques used to implant cardiac leads such as pacemaker leads. One proposed system for implanting the device includes an elongated introducer configured for being releasably coupled to the device. The introducer is preferably flexible to permit it to advance the device into the heart and into the coronary sinus through the coronary sinus ostium. To promote guidance, an elongated sheath is first advanced into the coronary sinus. Then, the device and introducer are moved through a lumen of the sheath until the device is in position within the coronary sinus. Because the device is formed of resilient material, it conforms to the curvatures of the lumen as it is advanced through the sheath. The sheath is then partially retracted to permit the device to assume its unstressed arched configuration. Once the device is properly positioned, the introducer is then decoupled from the device and retracted through the sheath. The procedure is then completed by the retraction of the sheath. As a result, the device is left within the coronary sinus to exert the inward pressure on the mitral valve to restore mitral valve geometry.  
           [0012]    The foregoing therapy has many advantages over the traditional open heart surgery approach. Since the device, system and method may be employed in a comparatively noninvasive procedure, mitral valve regurgitation may be treated at an early stage in the mitral regurgitation progression. Further, the device may be placed with relative ease by any minimally invasive cardiologist. Still further, since the heart remains completely intact throughout the procedure, the effectiveness of the procedure may be readily determined. Moreover, should adjustments be deemed desirable, such adjustments may be made during the procedure and before the patient is sent to recovery.  
           [0013]    Unfortunately, the human anatomy does impose some obstacles to this recently proposed procedure for treating mitral regurgitation. More specifically, the human heart includes a coronary artery which descends from the aorta. One branch of the coronary artery is the circumflex artery which, in turn, includes the left marginal branch of the circumflex artery. As used herein, the term “circumflex artery” is taken to include the circumflex artery itself or any branch therefrom. The circumflex artery extends distally generally along the coronary sinus but at a point proximal to the coronary artery, it passes under the coronary sinus. The circumflex artery supports blood flow important to the viability of the heart. Hence, reduction in this blood flow must be avoided. As a result, a device placed in the coronary sinus must not be permitted to extend within the coronary sinus beyond the crossover point of the circumflex artery and the coronary sinus to avoid constriction of the circumflex artery. This contemplates the need to know the location of the circumflex artery and coronary sinus crossover point. It also contemplates accurate positioning of the device within the coronary sinus to assure that the device does not extend over the circumflex artery.  
           [0014]    The present invention addresses these issues. The present invention provides a therapy system and procedure which enables accurate positioning of the therapy device. This enables effective treatment while also avoiding the crossover of the circumflex artery with the coronary sinus. Further, the present invention enables the positioning of the device with relative ease.  
         SUMMARY OF THE INVENTION  
         [0015]    The present invention provides an assembly for effecting the condition of a mitral valve of a heart. The assembly includes a mitral valve therapy device configured to reshape the mitral valve annulus of the heart when placed within the coronary sinus adjacent the mitral valve annulus, a guide wire configured to be fed into the coronary sinus of the heart adjacent the mitral valve annulus, and a guide tube having a distal end, a proximal end, and a lumen extending between the distal end and the proximal end, the guide tube further including a side port, intermediate the distal end and the proximal end and communicating with the lumen, to permit the guide tube to be slidingly received on the guide wire with the guide wire extending from the distal end, through the lumen, and out the side port. As a result, the guide tube is slidable along the guide wire to a position adjacent the mitral valve annulus within the coronary sinus and the mitral valve therapy device is guidable within the guide tube for placement in the coronary sinus adjacent the mitral valve annulus.  
           [0016]    The present invention further provides a method of deploying a mitral valve therapy device within the coronary sinus of a heart adjacent the mitral valve annulus. The method includes the steps of providing an elongated flexible guide wire having a cross sectional dimension, feeding the guide wire into the coronary sinus of the heart, providing an elongated flexible guide tube having a proximal end, a distal end, a lumen, and a side port communicating with the lumen, and feeding the guide tube into the coronary sinus of the heart with the guide wire extending through the lumen from the distal end to and through the side port. The method further includes the steps of providing a mitral valve therapy device configured to be slidingly received within the lumen of the guide tube, the device including a proximal end, providing a flexible elongated introducer configured to be slidingly received within the lumen of the guide tube, the introducer having a distal end, placing the device into the guide tube lumen, placing the introducer into the guide tube lumen, engaging the distal end of the introducer with the proximal end of the device, pushing the device with the introducer in a distal direction within the guide tube lumen until the device is at least partially encircling the mitral valve within the coronary sinus of the heart, and releasing the device from the guide tube into the coronary sinus of the heart adjacent to the mitral valve annulus.  
           [0017]    The guide wire may be visible under X ray fluoroscopy and the method may include the further steps of inserting a second wire into the circumflex artery of the heart, the second wire being visible under X ray fluoroscopy, subjecting the heart to X ray fluoroscopic examination to visualize the crossover point of the guide wire and the second wire, and releasing the mitral valve annulus therapy device within the coronary sinus in a position such that the device is proximal to the crossover point of the guide wire and the second wire.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with further aspects and advantages thereof, may best be understood by making reference to the following description taken in conjunction with the accompanying drawings, and the several figures of which like reference numerals identify identical elements, and wherein:  
         [0019]    [0019]FIG. 1 is a superior view of a human heart with the atria removed;  
         [0020]    [0020]FIG. 2 is a perspective view of a mitral valve annulus constricting device which may be utilized in accordance with an embodiment of the present invention;  
         [0021]    [0021]FIG. 3 is a perspective view of an assembly for treating a mitral valve in accordance with a preferred embodiment of the present invention;  
         [0022]    [0022]FIG. 4 is another superior view of a human heart illustrating deployment of a mitral valve therapy device in accordance with the preferred embodiment of the present invention;  
         [0023]    [0023]FIG. 5 is another superior view of a human heart illustrating an implanted mitral valve therapy device embodying the present invention;  
         [0024]    [0024]FIG. 6 is another view of a human heart illustrating the method of determining the crossover point of the circumflex artery and the coronary sinus in accordance with the present invention; and  
         [0025]    [0025]FIG. 7 is a perspective view of another assembly embodying the present invention for treating a mitral valve.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0026]    Referring now to FIG. 1, it is a superior view of a human heart  10  with the atria removed to expose the mitral valve  12 , the coronary sinus  14 , the coronary artery  15 , and the circumflex artery  17  of the heart  10  to lend a better understanding of the present invention. Also generally shown in FIG. 1 are the pulmonary valve  22 , the aortic valve  24 , and the tricuspid valve  26  of the heart  10 .  
         [0027]    The mitral valve  12  includes an anterior cusp  16 , a posterior cusp  18  and an annulus  20 . The annulus encircles the cusps  16  and  18  and maintains their spacing to provide a complete closure during a left ventricular contraction. As is well known, the coronary sinus  14  partially encircles the mitral valve  12  adjacent to the mitral valve annulus  20 . As is also known, the coronary sinus is part of the venus system of the heart and extends along the AV groove between the left atrium and the left ventricle. This places the coronary sinus essentially within the same plane as the mitral valve annulus making the coronary sinus available for placement of the mitral valve therapy device of the present invention therein.  
         [0028]    Of particular importance is the physiological relationship of the coronary sinus  14  and the circumflex artery  17 . The circumflex artery  17  branches from the coronary artery  15  and supplies blood flow to critical tissue of the heart  10 . The circumflex artery passes beneath the coronary sinus  14  at a crossover point  19 . It is one aspect of the present invention to avoid constriction of blood flow through the circumflex artery  17  when a mitral valve therapy device is deployed in the coronary sinus  14 .  
         [0029]    [0029]FIG. 2 shows a mitral valve therapy device  30  embodying the present invention. As may be noted in FIG. 2, the device is elongated and has an arched configuration to at least partially encircle the mitral valve  12  adjacent to the mitral valve annulus  20  when implanted in the coronary sinus  14 . The device  30  has an unstressed preformed arched radius smaller than the radius of the dilated mitral valve annulus  20 . This causes the device  30  to constrict the mitral valve annulus and impart an inward, generally radial force on the mitral valve annulus  20  when implanted in the coronary sinus of the heart. This force reshapes and returns the mitral valve annulus  20  to its original or substantially original geometry to permit the cusps  16  and  18  to more fully come together for sealing the left atrium during left ventricular contraction.  
         [0030]    The device  30  has a cross section dimension to be received by the coronary sinus. It is preferably formed of a resilient material permitting the device to be straightened and/or bent for being advanced into the coronary sinus. After being positioned within the coronary sinus, the device is permitted to assume its preformed arched configuration to act upon the mitral valve annulus as previously described. To that end, the device may be formed of, for example, Nitinol, a nickel titanium alloy, well known in the art. This material, as is well known, is capable of being preformed but manipulated to be straight or partially bent while having sufficient memory to return to its preformed configuration. Stainless steel is also among the materials which may be used in forming the device  30 . In order to be received within the coronary sinus, the device may have a cross sectional dimension of, for example, on the order of four or five french.  
         [0031]    With continued reference to FIG. 2, the device  30  has a distal end  34  and a proximal end  36 . Between the distal end  34  and proximal end  36  the device further includes a channel  38  which is aligned with a bore  40  extending through the distal end  34 . As will be seen subsequently, the bore  40  permits the device to be slidingly received by a guide wire during deployment of the device  30 . The guide wire, during deployment, is confined within the channel  38 .  
         [0032]    [0032]FIG. 3 illustrates an assembly  50  for deploying or implanting the mitral valve therapy device  30 . The assembly  50  includes a guide wire  52 , a guide tube  54 , and an elongated introducer  56 .  
         [0033]    The guide wire  52  is preferably an elongated coil. It has an outer dimension to permit the guide wire  52  to be passed through the bore  40  of the device  30 . This enables the device  30  to be slidingly received on the guide wire  52  with the guide wire confined within the channel  38  of the device  30 .  
         [0034]    The guide tube  54  is elongated and formed of a flexible biocompatible material. It includes an inner lumen  55  extending between a distal end  57  and a proximal end  59  permitting the device  30  and the introducer  56  to be received therein. The guide tube  54  further includes a side port  58  between the distal end  57  and the proximal end  59 . The side port  58  communicates with the lumen  55  to permit the guide tube  54  to be received on the guide wire  52 . More specifically, the guide tube  54  is slidingly received on the guide wire  52  with the guide wire extending through the lumen from the distal end  57  to and through the side port  58 . This permits the guide tube  54  to be advanced along the guide wire  52  during implant of the device  30 .  
         [0035]    The introducer  56  preferably takes the form of an elongated tube having an inner channel  60  and a slot  62  at its distal end dimensioned to be received by and slid onto the guide wire  52 . This enables the introducer  56  to be slid onto the guide wire  52  and to engage the proximal end of the device  30  during deployment of the device.  
         [0036]    As previously mentioned, the circumflex artery  17  passes under the coronary sinus  14 . When the device  30  is deployed, it should not be permitted to exert a force from the coronary sinus against the circumflex artery. Hence, in accordance with one embodiment of the present invention, the device is implanted within the coronary sinus at a position whereby the distal end  34  of the device  30  is proximal to the crossover point of the circumflex artery and the coronary sinus. This requires determination of the crossover point. FIG. 6 illustrates how such a determination may be made in accordance with the present invention.  
         [0037]    An elongated member, such as an elongated wire or coil wire  70  is inserted into the circumflex artery  17 . The wire  70  may be formed of a material visible under X ray fluoroscopy or be of other material having a coating which is visible under X ray fluoroscopy. Next, another wire which may be the guide wire  52  is inserted into the coronary sinus  14  by way of the ostium of coronary sinus  13 . Again, the wire  52  is preferably of a material visible under X ray fluoroscopy or of another material having a coating which is visible under X ray fluoroscopy. Preferably, the wires  52  and  70  are elongated coils formed of stainless steel.  
         [0038]    The heart  10  or at least that portion of the heart  10  where the circumflex artery passes under the coronary sinus is subjected to X ray fluoroscopy. X ray fluoroscopy is well known in the art. The crossover point  19  where the wires  52  and  70  cross and hence where the circumflex artery and coronary sinus cross may then be readily observed by X ray fluoroscopic examination. This locates the crossover point  19  which is to be distal to the distal end  34  of the device  30  when the device  30  is positioned within the coronary sinus.  
         [0039]    Once the crossover point  19  has been determined, the device  30  may be deployed. During the deployment of the device, the first wire  70  may be left in the circumflex artery to permit continuous X ray fluoroscopic examination or later X ray fluoroscopic examination to confirm proper device positioning.  
         [0040]    [0040]FIG. 4 shows how the assembly  50  may be used to implant the device  30 . Presumably the guide wire  52  has already been positioned in the coronary sinus  14  to support the determination of the circumflex artery and coronary sinus crossover point as described above. As also described above, wire  70  may also be left in the heart at this time.  
         [0041]    Next, the device  30  is threaded onto the guide wire  52  and the guide tube  54  is slidingly mounted on the guide wire  52  as shown in FIG. 3. The device  30  is then slid into the distal end  57  of the guide tube  54 . The guide tube  54  is then advanced into the heart. The guide tube is advanced on the guide wire  52 . The guide wire hence guides the guide tube  54  into the coronary sinus where the device is to be implanted.  
         [0042]    When the guide tube  54  is positioned in the coronary sinus, the introducer  56  is then advanced into the guide tube  54  and over the guide wire  52 . The distal end of the introducer  56  engages the proximal end  36  of the device  30 .  
         [0043]    With the distal end of the introducer  56  engaging the proximal end  36  of the device  30 , the guide tube may be slightly retracted and the device may then be pushed by the introducer  56  out of the guide tube  54  and into the coronary sinus  14  while remaining on the guide wire  52 .  
         [0044]    When the device is positioned within the coronary sinus  14  with its distal end proximal to the crossover point  19  and its position is confirmed by X ray fluoroscopy, the introducer may be removed. Then, the guide tube  54  may also be retracted leaving the device in place but still on the guide wire  52 . The performance of the device  30  may now be evaluated.  
         [0045]    Once the device satisfies the requirements of the procedure, the guide wire  52 , and the wire  70  if still within the heart, may be removed. This leaves the device  30  in its proper position as illustrated in FIG. 5. Here it may be seen that the device  30  partially encircles the mitral valve  12  within the coronary sinus  14  and adjacent to the mitral valve annulus. The distal end  34  of the device  30  is proximal to the crossover point  19 . The proximal end  36  of the device protrudes slightly into the right atrium (not shown) through the ostium of coronary sinus  13 .  
         [0046]    [0046]FIG. 7 shows another assembly  150  for treating a mitral valve embodying the present invention. The assembly may utilize the same device  30  and guide wire  52  as previously described. Here, however, a different guide tube  154  and introducer  156  are employed. The guide tube includes a bore  157  extending from the distal end of the guide tube to a side port  158 . The bore receives the guide wire  52  as shown to permit the guide tube  154  to slide on the guide wire  52 . The guide tube  154  further has a lumen  155  for receiving the device  30  and the introducer. A delivery slot  162  is proximal to the side port  158  and communicates with the lumen  155 . Hence, when the guide tube is within the coronary sinus, the introducer may push the device through the lumen  155  and out the delivery slot  162  into the coronary sinus for deployment. As will be appreciated by those skilled in the art, the lumen  155  and bore  157  may communicate to form a single lumen. The side port  158  may then communicate with the single lumen in the same manner as shown in FIG. 3.  
         [0047]    The introducer  156  need not be received by the guide wire  52  in this embodiment. Hence, the introducer  156  need not be slotted as shown in FIG. 3 and preferably takes the form of an elongated coil.  
         [0048]    As can thus be seen from the foregoing, the present invention provides a new and improved assembly and method for treating mitral regurgitation. The device may be rapidly deployed with only percutaneous techniques. Further, the mitral valve therapy device may be implanted in a manner which avoids the crossover point of the circumflex artery and coronary sinus. Lastly, the effectiveness of the therapy may be immediately deduced during the implant procedure.  
         [0049]    While particular embodiments of the present invention have been shown and described, modifications may be made, and it is therefore intended in the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the invention.