Sergical procedures and devices for increasing cardiac output of the heart

Abstract

Methods and devices for passively assisting the cardiac function of the heart are disclosed. A method of increasing the cardiac output of a heart includes providing a site of surgical access to the portion of the heart to be restrained, reducing the cardiac expansion of the portion of the heart to be restrained, and maintaining the reduction of cardiac expansion of the portion of the heart to be restrained for a substantial amount of time. Cardiac assist devices for increasing the cardiac output of the heart are disclosed comprising a reinforcing portion configured to contact a portion of the heart tissue wherein the reinforcing portion restricts the expansion of the portion of the heart tissue. The reinforcing portion can be a number of structures, including pads, frames, straps, and other retaining means for limiting cardiac expansion of the portion of the heart tissue to be retained.

1 . A cardiac assist device for increasing the cardiac output of the heart comprising a reinforcing portion configured to contact a portion of the heart tissue wherein the reinforcing portion restricts the expansion of the portion of the heart tissue. 
     
     
         2 . The device of  claim 1  wherein the reinforcing portion comprises a patch of material installed in facing engagement to the portion of the heart tissue to be restrained. 
     
     
         3 . The device of  claim 2  wherein the patch of material is fixed in facing engagement to the portion of the heart tissue to be restrained using a plurality of sutures. 
     
     
         4 . The device of  claim 2  wherein the patch of material is fixed in facing engagement to the portion of the heart tissue to be restrained using a plurality of staples. 
     
     
         5 . The device of  claim 3  wherein the patch of material is comprised of a biocompatible material. 
     
     
         6 . The device of  claim 1  wherein the reinforcing portion comprises a pad assembly engaging the portion of heart to be restrained, the pad assembly configured to restrict the cardiac expansion of the portion of the heart to be restrained. 
     
     
         7 . The device of  claim 6  wherein the pad assembly includes a harness assembly configured to hold the pad assembly in contact with the portion of the heart tissue to be restrained. 
     
     
         8 . The device of  claim 7  wherein the harness assembly comprises at least one frame member encircling the heart. 
     
     
         9 . The device of  claim 7  wherein the harness assembly comprises at least one relatively flexible strap encircling the heart. 
     
     
         10 . The device of  claim 7  wherein the harness assembly comprises a net member encircling the heart. 
     
     
         11 . The device of  claim 6  wherein the pad assembly is held in contact with the portion of the heart tissue to be restrained with an anchor member, the anchor member having a first end and a second end, wherein the first end is fixed to the pad assembly and the second end is configured to be anchored to a structure relatively fixed in relation to the portion of the heart to be restrained. 
     
     
         12 . The device of  claim 11  wherein the second end of the anchor member is configured to be fixed to the rib of a patient. 
     
     
         13 . The device of  claim 11  wherein the second end of the anchor member is configured to be fixed to the sternum bone of a patient. 
     
     
         14 . The device of  claim 11  wherein the second end of the anchor member is configured to be fixed to the wall of the heart opposite the portion of the heart to be restrained. 
     
     
         15 . The device of  claim 14  wherein the second end of the anchor member comprises an expandable member configured to engage the wall of the heart opposite the portion of the heart to be restrained. 
     
     
         16 . The device of  claim 1  wherein the reinforcing portion is an annular ring engaging the portion of the heart to be restrained. 
     
     
         17 . The device of  claim 16  wherein the ring is sutured to the portion of the heart to be restrained. 
     
     
         18 . The device of  claim 16  wherein the ring is stapled to the portion of the heart to be restrained. 
     
     
         19 . The device of  claim 1  wherein the reinforcing portion comprises a plurality of pad members fixed to the surface of the heart and at least one strap member joining the pad members, the at least one strap member sufficiently tensioned to reduce cardiac expansion in the portion of the heart to be restrained. 
     
     
         20 . A method of passively increasing the cardiac output of a heart, the method comprising:
 a) providing a site of surgical access to a portion of the heart to be restrained;   b) reducing the cardiac expansion of the portion of the heart to be restrained; and   c) maintaining the reduction of cardiac expansion of the portion of the heart to be restrained postoperatively.   
     
     
         21 . The method of  claim 20 , further comprising assessing the degree of cardiac assistance achieved from the reduction of cardiac expansion in the portion of the heart to be restrained. 
     
     
         22 . The method of  claim 20  wherein said reducing the cardiac expansion of the portion of the heart to be restrained comprises installing a plurality of sutures in the portion of the heart to be restrained. 
     
     
         23 . The method of  claim 22  wherein the plurality of sutures delineate the portion of the heart to be restrained. 
     
     
         24 . The method of  claim 20  wherein said reducing the cardiac expansion of the portion of the heart to be restrained comprises installing a patch of reinforcing material in facing engagement with the portion of the heart to be restrained. 
     
     
         25 . The method of  claim 20  wherein the patch of reinforcing material is installed in facing engagement with portion of the heart to be restrained using a plurality of sutures. 
     
     
         26 . The method of  claim 20  wherein said reducing the cardiac expansion of the portion of the heart to be restrained comprises fixing a portion of the pericardium of a patient to the portion of the heart to be restrained. 
     
     
         27 . The method of  claim 20  wherein said reducing the cardiac expansion of the portion of the heart to be restrained comprises anchoring the portion of the heart to be restrained to a body structure which is relatively fixed in relation to the portion of the heart to be restrained. 
     
     
         28 . The method of  claim 27  wherein said anchoring the portion of the heart to be restrained comprises fixing an anchoring end of an anchoring member to a pad assembly, wherein the pad assembly contacts the portion of the heart to be restrained; and fixing a reinforcement end of the anchoring member to a rib of the patient. 
     
     
         29 . The method of  claim 27  wherein said anchoring the portion of the heart to be restrained comprises:
 fixing an anchoring end of an anchoring member to a pad assembly;   contacting the portion of the heart to be restrained with the pad assembly; and   fixing a reinforcement end of the anchoring member to the sternum bone of the patient.   
     
     
         30 . The method of  claim 27  wherein said anchoring the portion of the heart to be restrained comprises the steps of:
 fixing an anchoring end of an anchoring member to a pad assembly,   fixing the pad assembly is to the portion of the heart to be restrained, and   fixing a reinforcing end of the anchoring member to the wall of the heart opposite the portion of the heart to be restrained.   
     
     
         31 . The method of  claim 27  wherein said anchoring the portion of the heart to be restrained comprises:
 making a first puncture hole in the portion of the heart to be restrained with a puncturing device;   inserting the puncturing device into the first puncture hole and making a second puncture hole in the wall of the heart opposite the portion of the heart to be restrained;   advancing a cardiac assist device through the first and second puncture holes, the cardiac assist device comprising an anchoring member, an anchoring end at a distal end of the anchoring member, and a pad assembly fixed to the anchoring member proximal to the anchoring end;   engaging the wall of the heart opposite the portion of the heart to be restrained with the anchoring end of the anchoring member; and   engaging the portion of the heart to be restrained with the pad assembly so as to limit cardiac expansion in the portion of the heart to be restrained.   
     
     
         32 . The method of  claim 31  wherein the anchoring end comprises an expandable member, wherein the step of engaging the wall of the heart opposite the portion of the heart to be restrained comprises expanding the expandable member to engage the wall of the heart opposite the portion of the heart to be restrained. 
     
     
         33 . The method of  claim 31  wherein the puncturing device comprises a trocar sheath configured to be disposed about the cardiac assist device, wherein the step of advancing the cardiac assist device through the first and second puncture holes comprises advancing the cardiac assist device distally within the trocar sheath sufficiently to engage the wall of the heart opposite the portion of the heart to be restrained with the anchoring end, including the additional step of withdrawing the trocar sheath proximally from about the cardiac assist device prior to engaging the portion of the heart to be restrained with the pad assembly. 
     
     
         34 . The method of  claim 33  wherein the anchoring end comprises an expandable member, and wherein said engaging the wall of the heart opposite the portion of the heart to be restrained comprises expanding the expandable member to engage the wall of the heart opposite the portion of the heart to be restrained. 
     
     
         35 . The method of  claim 34  wherein said expanding the expandable member comprises providing inflation fluid to the expandable member through an inflation lumen provided within the anchoring member. 
     
     
         36 . The method of  claim 34  wherein said expanding the expandable member comprises releasing a vacuum acting on the expandable member. 
     
     
         37 . The method of  claim 34  further comprising closing the site of surgical access to the portion of the heart to be restrained while maintaining the reduction of the cardiac expansion of the portion of the heart to be restrained. 
     
     
         38 . The method of  claim 20  further comprising placing the patient on cardiopulmonary bypass prior to reducing the cardiac expansion of the portion of the heart to be restrained. 
     
     
         39 . The method of  claim 20  wherein said reducing the cardiac expansion of the portion of the heart to be restrained comprises injecting a hardenable material into the cardiac tissue so as to stiffen the portion of the heart to be restrained. 
     
     
         40 . The method of  claim 39  wherein the hardenable material is injected into a furrow created in the surface of the heart. 
     
     
         41 . The method of  claim 39  wherein said injecting a hardenable material in the cardiac tissue comprises:
 inserting a needle having a fluid lumen therethrough into the cardiac tissue of the portion of the heart to be restrained;   forming a needle track in the cardiac tissue by advancing the needle through the cardiac tissue at an obtuse angle to the surface of the cardiac tissue so that a distal end of the needle does not exit the cardiac tissue; and   withdrawing the needle simultaneously with injecting a hardenable material into the needle track through the fluid lumen of the needle.   
     
     
         42 . The method of  claim 39  wherein the hardenable material is a procoagulant material. 
     
     
         43 . The method of  claim 42 , further comprising repeating said inserting a needle, forming a needle track and withdrawing the needle simultaneously with injecting to form a plurality of hardened needle tracks in the portion of the heart to be restrained. 
     
     
         44 . The method of  claim 20  wherein said reducing the cardiac expansion of the portion of the heart to be restrained comprises injecting a material into the cardiac tissue to encourage the formation of scar tissue. 
     
     
         45 . The method of  claim 20  wherein the method is performed in a minimally invasive manner. 
     
     
         46 . The method of  claim 20  wherein the method is performed on a beating heart. 
     
     
         47 . The method of  claim 20  wherein said reducing the cardiac expansion of the portion of the heart to be restrained comprises:
 providing surgical access to the left ventricle of the heart;   severing the chordae tendineae from the mitral valve;   fixing a free end of the severed chordae tendineae to the septal wall of the heart opposite the portion of the heart to be restrained so as to limit the ventricular expansion of the portion of the heart to be restrained; and   replacing the mitral valve with a prosthetic valve.   
     
     
         48 . The method of  claim 47  wherein the method is performed in a minimally invasive manner. 
     
     
         49 . A device for displacing a volume of a portion of a diseased heart comprising:
 an expandable member configured to fit into a chamber of the diseased heart and reduce the available blood volume of the chamber of the heart; and   an inflation portion.   
     
     
         50 . The device of  claim 49  wherein the expandable member is preformed to conform the volume of the diseased ventricle into a closer approximation of the volume of a healthy ventricle. 
     
     
         51 . The device of  claim 49  wherein the inflation portion comprises an inflation tube. 
     
     
         52 . A method of increasing the cardiac performance of an enlarged heart comprising:
 a) providing a surgical access site to a chamber of the enlarged heart;   b) permanently displacing a portion of the blood volume of the chamber of the enlarged heart; and   c) closing the surgical access site to a chamber of the enlarged heart.   
     
     
         53 . The method of  claim 52  wherein said providing a surgical access site to a chamber of the enlarged heart comprises making an incision through the pericardium and myocardium of the left ventricle. 
     
     
         54 . The method of  claim 52  wherein said providing a surgical access site to a chamber of the enlarged heart comprises accessing the left ventricle of the heart through the aorta of the patient. 
     
     
         55 . The method of  claim 52  wherein said permanently displacing a portion of the blood volume of the chamber of the enlarged heart comprises:
 installing a ventricular displacement device comprising an inflation portion and an expandable member into the chamber of the heart; and   expanding the expandable member to displace a portion of the blood volume of the chamber of the heart.   
     
     
         56 . The method of  claim 55  wherein the inflation portion comprises a tubular member having a first end in fluid communication with the expandable member and a second free end, and wherein said installing a ventricular displacement device comprises fixing the ventricular displacement device to an internal surface of the ventricle so that the free end of the inflation portion extends through the incision in the ventricle into the chest cavity of the patient. 
     
     
         57 . The method of  claim 53  wherein said permanently displacing a portion of the blood volume of the chamber of the enlarged heart comprises:
 installing a ventricular displacement device comprising an inflation portion and an expandable member in the chamber of the diseased heart; and   expanding the expandable member to displace a portion of the blood volume of the chamber of the heart.   
     
     
         58 . The method of  claim 57  wherein said installing a ventricular displacement device comprises fixing the device to an internal surface of the ventricle. 
     
     
         59 . The method of  claim 57 , further comprising:
 assessing the clinical effect of permanently displacing a portion of the blood volume of the chamber of the enlarged heart; and   repeating said installing a ventricular device and said expanding the expandable member to install additional ventricular displacement devices as the clinical situation indicates.   
     
     
         60 . The method of  claim 53  wherein said permanently displacing a portion of the blood volume of the chamber of the enlarged heart comprises:
 repairing the incision in the pericardium of the left ventricle;   pushing the pericardium into the ventricle through the incision in the myocardium to form a pericardial sack in the left ventricle;   providing inflation fluid to the pericardial sack to fill the pericardial sack and displace a portion of the blood volume of the ventricle; and   closing the incision in the myocardium to close surgical access to the ventricle and to seal the inflation fluid in the pericardial sack.