Abstract:
This invention is directed to a device and method of using the device for partitioning a patient&#39;s heart chamber into a productive portion and a non-productive portion. The device is particularly suitable for treating patients with congestive heart failure. The device has an inflatable partitioning element which separates the productive and non-productive portions of the heart chamber and in some embodiments also has a supporting element, which may also be inflatable, extending between the inflatable partitioning element and the wall of the non-productive portion of the patient&#39;s heart chamber. The supporting element may have a non-traumatic distal end to engage the ventricular wall or a tissue penetrating anchoring element to secure the device to the patient&#39;s heart wall.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of application Ser. No. 10/791,916 filed Mar. 3, 2004, entitled, “Inflatable Ventricular Partitioning Device.” 
    
    
     INCORPORATION BY REFERENCE 
     All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. 
     FIELD OF THE INVENTION 
     The present invention relates generally to the field of treating congestive heart failure and more specifically, to a device and method for partitioning a patient&#39;s heart chamber and a system for delivering the treatment device. 
     BACKGROUND OF THE INVENTION 
     Congestive heart failure (CHF) is characterized by a progressive enlargement of the heart, particularly the left ventricle and is a major cause of death and disability in the United States. Approximately 500,000 cases occur annually in the U.S. alone. As the patient&#39;s heart enlarges, it cannot efficiently pump blood forward with each heart beat. In time, the heart becomes so enlarged the heart cannot adequately supply blood to the body. Even in healthy hearts only a certain percentage of the blood in a patient&#39;s left ventricle is pumped out or ejected from the chamber during each stroke of the heart. The pumped percentage, commonly referred to as the “ejection fraction”, is typically about sixty percent for a healthy heart. A patient with congestive heart failure can have an ejection fraction of less than 40% and sometimes lower. As a result of the low ejection fraction, a patient with congestive heart failure is fatigued, unable to perform even simple tasks requiring exertion and experiences pain and discomfort. Further, as the heart enlarges, the internal heart valves such as the mitral valve, cannot adequately close. An incompetent mitral valve allows regurgitation of blood from the left ventricle back into the left atrium, further reducing the heart&#39;s ability to pump blood forewardly. 
     Congestive heart failure can result from a variety of conditions, including viral infections, incompetent heart valves (e.g. mitral valve), ischemic conditions in the heart wall or a combination of these conditions. Prolonged ischemia and occlusion of coronary arteries can result in myocardial tissue in the ventricular wall dying and becoming scar tissue. Once the myocardial tissue dies, it is less contractile (sometimes non-contractile) and no longer contributes to the pumping action of the heart. It is referred to as hypokinetic. As the disease progresses, a local area of compromised myocardium may bulge out during the heart contractions, further decreasing the heart&#39;s ability to pump blood and further reducing the ejection fraction. In this instance, the heart wall is referred to as dyskinetic or akinetic. The dyskinetic region of the heart wall may stretch and eventually form an aneurysmic bulge. 
     Patients suffering from congestive heart failure are commonly grouped into four classes, Classes I, II, III and IV. In the early stages, Classes I and II, drug therapy is presently the most commonly prescribed treatment. Drug therapy typically treats the symptoms of the disease and may slow the progression of the disease, but it can not cure the disease. Presently, the only permanent treatment for congestive heart disease is heart transplantation, but heart transplant procedures are very risky, extremely invasive and expensive and are performed on a small percentage of patients. Many patient&#39;s do not qualify for heart transplant for failure to meet any one of a number of qualifying criteria, and, Furthermore, there are not enough hearts available for transplant to meet the needs of CHF patients who do qualify. 
     Substantial effort has been made to find alternative treatments for congestive heart disease. For example, surgical procedures have been developed to dissect and remove weakened portions of the ventricular wall in order to reduce heart volume. This procedure is highly invasive, risky and expensive and is commonly only done in conjunction with other procedures (such as heart valve replacement or coronary artery by-pass graft). Additionally, the surgical treatment is usually limited to Class IV patients and, accordingly, is not an option for patients facing ineffective drug treatment prior to Class IV. Finally, if the procedure fails, emergency heart transplant is the only presently available option. 
     Other efforts to treat CHF include the use of an elastic support, such as an artificial elastic sock placed around the heart to prevent further deleterious remodeling. 
     Additionally, mechanical assist devices have been developed as intermediate procedures for treating congestive heart disease. Such devices include left ventricular assist devices and total artificial hearts. A left ventricular assist device includes a mechanical pump for increasing blood flow from the left ventricle into the aorta. Total artificial heart devices, such as the Jarvik heart, are usually used only as temporary measures while a patient awaits a donor heart for transplant. 
     Recently, improvements have been made in treating patient&#39;s with CHF by implanting pacing leads in both sides of the heart in order to coordinate the contraction of both ventricles of the heart. This technique has been shown to improve hemodynamic performance and can result in increased ejection fraction from the right ventricle to the patient&#39;s lungs and the ejection fraction from the left ventricle to the patient&#39;s aorta. While this procedure has been found to be successful in providing some relief from CHF symptoms and slowed the progression of the disease, it has not been able to stop the disease. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a ventricular partitioning device and method of employing the device in the treatment of a patient with congestive heart failure. Specifically, the ventricular chamber of the CHF patient is partitioned by the device so as to reduce its total volume and to reduce the stress applied to the heart and, as a result, improve the ejection fraction thereof. 
     A ventricular partitioning device embodying features of the invention has an inflatable partitioning element, which is configured to partition the patient&#39;s ventricular heart chamber into a main productive portion and a secondary non-productive portion. The inflatable partitioning element may be at least in part disc shaped and hollow. The partitioning device preferably has a supporting or spacing element extending from the distal side of the inflatable partitioning element for non-traumatically engaging a region of the patient&#39;s ventricular wall defining in part the secondary non-productive portion to space a central portion of the partitioning element from the heart wall. The supporting or spacing element may itself be inflatable and preferably has an interior in fluid communication with the interior of the partitioning element. 
     The supporting element of the device has a length configured to extend to the heart wall, supporting and spacing the partitioning element from the heart wall. The supporting element may have an inner lumen extending therein for delivery of therapeutic or diagnostic agents through the ports provided along the length thereof. 
     The partitioning device may be delivered percutaneously or intraoperatively. It is relatively easy to install and provides substantial improvement in the ejection fraction of the patient&#39;s heart chamber. A suitable delivery system is described in co pending application Ser. No. 10/212,032, filed on Aug. 1, 2002 which is incorporated herein in it&#39;s entirety. These and other advantages of the invention will become more apparent from the following detailed description of the invention and the accompanying exemplary drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a perspective view of a ventricular partitioning device in an inflated state embodying features of the invention. 
         FIG. 1B  is a perspective view of a ventricular portioning device in a deflated state embodying features of the invention. 
         FIG. 1C  is an enlarged view of the encircled region of  FIG. 1A   
         FIG. 2  is a schematic view of a patient&#39;s left ventricular chamber illustrating the partitioning device shown in  FIG. 1A  disposed within the chamber separating a working portion of the chamber from a non-working portion of the chamber. 
         FIG. 3  is a perspective view of an alternative design of the partitioning device without a supporting member. 
         FIG. 4  is a schematic view of a patient&#39;s left ventricular chamber illustrating the partitioning device being deployed on a delivery system. 
         FIG. 5  is a schematic view of the patient&#39;s left ventricular chamber illustrating the partitioning device Shown in  FIG. 3  disposed within the chamber separating a working portion of the chamber from a non-working portion of the chamber. 
         FIG. 6  is an elevational view of a delivery system for the partitioning device shown in  FIG. 3  with the inflatable partitioning element in a deflated condition. 
         FIG. 7  is an elevational view of a delivery system as shown in  FIG. 6  with the partitioning element in an inflated condition. 
         FIG. 8  is a perspective view of an alternative partitioning device which has an elongated, distally extending stem with non-traumatic bumper elements on the distal extremity. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1A and 1B  illustrate a partitioning device  10  which embodies features of the invention and which includes an inflatable partitioning element  12  and an inflatable supporting element  14 . The partitioning element  12  may contain anchoring members  16  around its edge  18  to engage the heart wall  20  upon expansion. The partitioning device  10  is delivered in a deflated form through a catheter. The inflatable partitioning element may be disc shaped and hollow. When inflated the supporting element  14  extends distally from the center of the partitioning element  12  and has a distal end  22  which provides a yielding engagement with a heart wall  20  when deployed within a patient&#39;s heart chamber  24 . 
     The partitioning element  12  has a peripheral edge  18 . The edge  18  may contain anchoring members  16  which are configured to hold the partitioning device  10  in a deployed position within the patient&#39;s heart chamber  24 . Preferably, the anchoring elements  16  penetrate into tissue of the patient&#39;s heart wall  20  in order to secure the partitioning element  12  so as to partition the ventricular chamber  24  in a desired manner. The partitioning element  12  may contain a hub  26  having a one way valve for inflation of both the partitioning element  12  and the supporting element  14 . 
       FIG. 2  illustrates the placement of partitioning device  10  within a patient&#39;s left ventricle  24 . The partitioning element  12  partitions the patient&#39;s heart chamber  24  into a main productive portion  27  and a secondary, essentially non-productive portion  28 . The productive portion  27  is smaller than the original ventricular chamber  24  and provides for an improved ejection fraction. The partitioning increases the ejection fraction and provides an improvement in blood flow through the heart chamber. Over time, the non-productive portion  28  fills initially with thrombus and subsequently cellular growth. Bio-resorbable fillers such as polylactic acid, polyglycolic acid, polycaprolactone and copolymers and blends may be employed to fill the non-productive portion  28 . Fillers may be suitably supplied in a suitable solvent such as DMSO. Other materials which accelerate tissue growth may be deployed in the non-productive portion  28 . In some embodiments the supporting element  14  may fill a portion or all of the non-productive chamber  28 . 
     An alternative partitioning device  30  is shown in  FIG. 3  wherein the inflatable partitioning element  32  is held in place by anchoring members  34  disposed about the periphery  36 . In this embodiment the partitioning element  32  does not have a distal supporting element extending from it&#39;s distal face  38 . The proximal face  40  has a hub  42  which has a inflation port for injection inflation fluid into the interior of the element  32 . 
     A suitable delivery system for the partitioning devices described above is described in co-pending application Ser. No. 10/212,032 filed on Aug. 1, 2002 which is incorporated herein in its entirety.  FIGS. 4 ,  6  and  7  illustrate a suitable delivery system  44  with a partitioning device  30  as shown in  FIG. 3 . The delivery system  44  includes a control handle  46  with a delivery catheter  48  and a detachment mechanism including coil  50  secured to the distal end of the delivery catheter for releasing the partitioning device  30  from the delivery system  44  The delivery catheter  48  may be provided with an inner lumen (not shown) through which therapeutic or diagnostic fluids may be delivered. The delivery catheter  48  extends through the handle  46  and the proximal end of the catheter  48  is connected to a balloon inflation port  52 . 
     As shown in  FIG. 4 , the delivery system  44  may be introduced into a patient&#39;s body through a percutaneously introduced guide catheter or cannula  54  which has an inner lumen (not shown). The partitioning device  30  is slidably disposed within the inner lumen of guide catheter  54 . The delivery system  44  is advanced distally within the inner lumen of the guide catheter  54  and engages the ventricular wall  56 . With the delivery system  44  held in place, the partitioning element  32  is inflated and the anchoring members  34  penetrate into tissue of the patient&#39;s heart wall  56 , as shown in  FIG. 5 , to secure the partitioning device  30  within the patient&#39;s heart chamber  58  to partition the chamber into productive portion  60  and non-productive portion  62 . The delivery system  44  and the guide catheter  54  may then be removed from the patient. The proximal end of the guide catheter  54  is provided with an injection port  64  to inject therapeutic or diagnostic fluids through the inner lumen thereof into the patient&#39;s heart chamber  58 . 
       FIG. 8  illustrates another alternative inflatable partitioning device  70  which has a partitioning element  72  and a stem  74  which extends distally from the distal face  76  of the partitioning element. The distal extremity of the stem  74  has three J-shaped bumpers  78  which allow for non-traumatic engagement with the wall of the patient&#39;s non-productive portion of the heart chamber. A variety of other non-traumatic bumpers may be employed, such as those described in co-pending application Ser. No. 10/754,182, which was filed on Jan. 9, 2004 and which was entitled “VENTRICULAR PARTITIONING DEVICE”. This application has been assigned to the present assignee and is incorporated herein in its entirety. The periphery of partitioning element  72  is provided with a plurality of anchoring elements  80  for securing the device to the ventricular wall. A hub  82  is provided on the proximal face  84  of the partitioning element  72  for delivery and inflation of the partitioning element as previously described. 
     To assist in properly locating the partitioning device during advancement and placement thereof into a patient&#39;s heart chamber, it may be provided with markers at desirable locations that provide enhanced visualization by eye, by ultrasound, by X-ray, or other imaging or visualization means. Radiopaque markers may be made with, for example, stainless steel, platinum, gold, iridium, tantalum, tungsten, silver, rhodium, nickel, bismuth, other radiopaque metals, alloys and oxides of these metals. 
     The partitioning device  10 ,  30  and  70  may be formed of suitable biocompatitble polymeric material which include expanded polytetrfluoroethylene (ePTFE), polyethylene terephthalate (PET), polyesters such as Hytrel.RTM., polyamides such as Nylon and polyurethane. The compliance may range from about 50 to about 1000%. The inflatable partitioning element of the device in the expanded configuration has radial dimensions from about 5 to about 60 mm, preferably about 20 to about 50 mm, as measured from the center line axis. The aspect ratio of the thickness of the inflatable partitioning element at its thickest portion to the diameter of the inflatable partitioning element is from about 1:10 to about 1:1, preferably about 1:10 to about 1:2. 
     The delivery catheter and the guide catheter may be formed of suitable high strength polymeric material such as PEEK (polyetheretherketone), polycarbonate, PET, Nylon, and the like. To the extent not otherwise described herein, the various components of the partitioning device and delivery system may be formed of conventional materials and in a conventional manner as will be appreciated by those skilled in the art. 
     The inflatable partitioning and support elements may be inflated with a variety of fluids, preferably liquids such as saline or contrast fluids. Liquids which become more viscous or harden in situ may also be used. If the inflatable elements are formed of bioabsorable materials, the inflation fluid should be readily absorbed within the patient&#39;s bloodstream and should not have significant detrimental affects. 
     While particular forms of the invention have been illustrated and described herein, it will be apparent that various modifications and improvements can be made to the invention. For example an inflatable partitioning element may be used to occlude an atrial appendage of the heart. Moreover, individual features of embodiments of the invention may be shown in some drawings and not in others, but those skilled in the art will recognize that individual features of one embodiment of the invention can be combined with any or all the features of another embodiment. Accordingly, it is not intended that the invention be limited to the specific embodiments illustrated. It is intended that this invention to be defined by the scope of the appended claims as broadly as the prior art will permit. 
     Terms such a “element”, “member”, “device”, “section”, “portion”, “steps”, “means” and words of similar import when used herein shall not be construed as invoking the provisions of 35 U.S.C. .sctn.112(6) unless the following claims expressly use the terms “means” followed by a particular function without specific structure or “step” followed by a particular function without specific action. All patents and patent applications referred to above are hereby incorporated by reference in their entirety. Accordingly, it is not intended that the invention be limited, except as by the appended claims.