Method and apparatus for mechanical transmyocardial revascularization of the heart

Abstract

An apparatus for creating revascularization channels in tissue, such as the myocardium of the heart, mechanically cuts the channels using a hand piece with easily removable cutting tip assemblies having angled, sharpened edges to allow rapid tip replacement. The cutting tip assembly has an inner needle within an outer hollow needle with each needle attached to the hand piece for independent rotation and axial movement. The inner needle may be hollow, or formed with a pointed tip, and may rotate counter to the outer needle to enhance gripping and storage of the tissue excised by the outer needle. The hand piece may attach a cylindrical magazine of cutting tip assemblies or one cutting tip assembly. The cutting tip assembly may be heated to provide thermal damage to the heart muscle during the creation of the channel, providing some of the advantages of the laser method of TMR.

What is claimed is:  
     
         1 . An apparatus for creating channels in tissue appropriate for improving blood flow and tissue regeneration, the apparatus comprising: 
 a generally cylindrical cutting assembly defining an axis;    tissue storage means within the cutting assembly for holding a core of tissue during and following mechanical cutting of tissue by the cutting assembly; and    means for advancing the cutting assembly into the tissue.    
     
     
         2 . The apparatus of    claim 1    wherein the cutting assembly comprises at least one needle having a hollow internal bore and a distal tip, the distal tip defining a sharpened edge disposed at a specified angle to the axis and surrounding the hollow internal bore.  
     
     
         3 . The apparatus of    claim 2    wherein the means for advancing the cutting assembly comprises a handpiece for attachment of the cutting assembly thereto, the handpiece having a rotation mechanism for rotating the cutting assembly and a translation mechanism for moving the cutting assembly axially.  
     
     
         4 . The apparatus of    claim 3    further comprising attachment means for removably connecting the cutting means to the handpiece.  
     
     
         5 . The apparatus of    claim 4    wherein the handpiece is powered for operating at least the rotation mechanism and the attachment means is at least one linkage connected to the cutting assembly and releasably mounting to the handpiece.  
     
     
         6 . The apparatus of    claim 5    wherein the handpiece comprises a housing for enclosing at least one motor having at least one output shaft; gear means attached to the at least one output shaft and operatively associated with the linkage, the gear means advancing and rotating the at least one needle axially into the tissue; controller means connected to the at least one motor for processing a preselected sequence of advancement and rotation of the at least one needle; and at least one actuator means for activating the motor.  
     
     
         7 . The apparatus of    claim 1    further comprising means for heating the cutting assembly.  
     
     
         8 . The apparatus of    claim 4    comprising an inner needle disposed within a hollow outer needle, the inner and outer needles each defining a substantially coincident lateral axis to allow relatively lateral translation between the inner needle and the outer needle, the attachment means enabling independent rotation and axial movement of the inner needle with respect to the outer needle.  
     
     
         9 . The apparatus of    claim 8    wherein the inner needle defines a hollow internal bore and a distal tip defining a sharpened edge disposed at a specified angle to the axis and surrounding the hollow internal bore.  
     
     
         10 . The apparatus of    claim 8    wherein the inner needle is shaped to define a drill tip configuration.  
     
     
         11 . The apparatus of    claim 8    wherein the inner needle is shaped to define a screw tip configuration.  
     
     
         12 . The apparatus of    claim 8    wherein the inner needle is hollow and defines a cylindrical outer wall, the tissue storage means is a cut away portion in the outer wall of the inner needle, and the inner needle defines a piercing tip at a distal end thereof.  
     
     
         13 . The apparatus of    claim 8    wherein the means for rotating includes rotation of the inner needle counter to the outer needle.  
     
     
         14 . The apparatus of    claim 5    wherein the hand piece further comprises vacuum means for applying a counterforce to cutting forces of the cutting assembly.  
     
     
         15 . The apparatus of    claim 2    wherein the storage means is the hollow internal bore of the at least one needle.  
     
     
         16 . The apparatus of    claim 4    for creating channels in cardiac muscle appropriate for transmyocardial revascularization, the apparatus further comprising a removable magazine attached to the handpiece, the magazine holding a plurality of cutting assemblies for automatically and rapidly rotating an unused cutting assembly into position within the handpiece to create each channel.  
     
     
         17 . The apparatus of    claim 16    wherein the cutting assembly further comprises a piercing tool for creating a small entry hole through epicardium to allow introduction of the at least one needle into myocardium.  
     
     
         18 . The apparatus of    claim 2    for creating channels in cardiac tissue appropriate for transmyocardial revascularization wherein the cutting assembly comprises a single needle having a hollow internal bore for retaining and storing excised cardiac tissue, the needle having a tapered distal tip defining a sharpened edge disposed at a specified angle to the axis and surrounding the hollow internal bore, the cutting assembly further comprising support means surrounding the tapered needle for supporting the cutting tip assembly in contact with the cardiac tissue during creation of the channels.  
     
     
         19 . A method for creating channels in the wall of the cardiac muscle appropriate for transmyocardial revascularization, the method comprising: 
 rotating an inner needle disposed within a bore of an outer needle about the inner needle's lateral axis;    orienting the lateral axis of the inner needle to insert with the surface of the external heart wall;    translating the inner needle laterally along said lateral axis until the inner needle cuts partway into the heart wall;    stabilizing the inner needle in the partial cut heart wall by ceasing rotation thereof;    rotating the outer needle about its lateral axis, the outer needle being disposed such that the lateral axis of the inner needle and the lateral axis of the outer needle are substantially coincident, the disposition of the inner needle within the bore of the outer needle allowing relative lateral translation between the inner needle and the outer needle;    translating the outer needle laterally along the lateral axis of the outer needle until the outer needle cuts the desired depth of channel into the heart wall and the excised tissue is held by the inner needle; and    laterally withdrawing the inner needle and the outer needle.    
     
     
         20 . The method of    claim 19    further comprising the step of heating the inner and outer needles to a temperature of at least 60 degrees Celsius.  
     
     
         21 . The method of    claim 20    further comprising the step of applying a suction counter force while rotating and advancing the outer needle.  
     
     
         22 . The method of    claim 19    further comprising the step of rotating the inner needle while rotating the outer needle, the inner needle being rotated in a direction counter to a direction of rotation of the outer needle.