Patent Publication Number: US-2009234327-A1

Title: Transmyocardial revascularization system and method of use

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of our earlier filed U.S. patent application Ser. No. 11/076,500, filed on Mar. 9, 2005, entitled Transmyocardial Revascularization System And Method Of Use, which is a Continuation of our earlier filed U.S. patent application Ser. No. 10/301,007, filed on Nov.21, 2002, entitled Transmyocardial Revascularization System And Method Of Use, now U.S. Pat. No. 6,955,681, which is in turn a Divisional of our earlier filed U.S. patent application Ser. No. 09/773,855, filed on Feb. 1, 2001, entitled Transmyocardial Revascularization System And Method Of Use, now U.S. Pat. No. 6,514,271, which is in turn a Continuation of our earlier filed U.S. patent application Ser. No. 09/369,107, filed on Aug. 5, 1999 entitled Transmyocardial Revascularization And Method Of Use, now U.S. Pat. No. 6,203,556, which in turn is a Continuation of our earlier filed U.S. patent application Ser. No. 08/958,788, filed on Oct. 29, 1997, entitled Transmyocardial Revascularization System, now U.S. Pat. No. 5,980,548, all of whose disclosures are incorporated by reference herein, and which are assigned to the same assignee as the subject invention. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates generally to medical systems and procedures and more particularly to systems and procedures for effecting revascularization of the myocardium of a living being. 
     Atherosclerosis is the leading cause of death in the industrial world today. During the disease process, atherosclerotic plaques develop at various locations within the arterial system of those affected. These plaques restrict the flow of blood through the affected vessels. Of particular concern is when these plaques develop within the blood vessels that feed the muscles of the heart. In healthy hearts, cardiac blood perfusion results from the two coronary arterial vessels, the left and right coronary arteries which perfuse the myocardium from the epicardial surface inward towards the endocardium. The blood flows through the capillary system into the coronary veins and into the right atrium via the coronary sinus. When atherosclerosis occurs within the arteries of the heart it leads to myocardial infarctions, or heart attacks, and ischemia due to reduced blood flow to the heart muscle. 
     Over the past few years numerous methods for treating cardiovascular disease have become available. Traditional methods utilize open surgical procedures to access the heart and bypass blockages in the coronary blood vessels. In these procedures, the patient&#39;s heart is surgically exposed and one or more coronary arteries are replaced/bypassed with synthetic or natural bypass grafts. During conventional cardiac surgery, the heart is stopped using cardioplegia solutions and the patient is put on cardiopulmonary bypass which uses a heart-lung machine to maintain circulation throughout the body during the surgical procedure. A state of hypothermia is induced in the heart tissue during the bypass procedure to preserve the tissue from necrosis. Once the procedure is complete, the heart is resuscitated and the patient is removed from bypass. There are great risks associated with these surgical procedures such as significant pain, extended rehabilitation times, and high risk of mortality for the patient. The procedure is time-consuming and costly to perform. This surgery also requires that the patient have both adequate lung and kidney function in order to tolerate the circulatory bypass associated with the procedure and a number of patients which are medically unstable are thus not a candidate for bypass surgery. As a result, over the past few years minimally invasive techniques for performing bypass surgery have been developed and in some instances the need for cardiopulmonary bypass and extended recovery times are avoided. In addition, as an alternative to surgical methods, non-surgical procedures, such as percutaneous transluminal coronary angioplasty, rotational atherectomy, and stenting have been successfully used to treat this disease in a less invasive non-surgical fashion. 
     In balloon angioplasty a long, thin catheter containing a tiny inflatable balloon at its distal end is threaded through the cardiovascular system until the balloon is located at the location of the narrowed blood vessel. The balloon is then inflated to compress the obstructing plaque against the arterial wall, thereby restoring or improving the flow of blood to the local and distal tissues. Rotational atherectomy utilizes a similarly long and thin catheter, but with a rotational cutting tip at its distal end for cutting through the occluding material. Stenting utilizes a balloon tipped catheter to expand a small coil-spring-like scaffold at the site of the blockage to hold the blood vessel open. While many patients are successfully relieved of their symptoms and pain, in a significant number of patients, the blood vessels eventually reocclude within a relatively short period of time. In addition, for a large number of patients that are in the later stages of ischemic heart disease, the current technology offers little hope for long term cure. In these patients even extending the patient&#39;s life for several months provides a significant benefit to the patients and their families. 
     Although these non-surgical procedures are much less costly and less traumatic to the patient than coronary bypass surgery there are a number of patients for which these procedures are not suitable. For certain types of patients the presence of extremely diffuse stenotic lesions and total occlusion in tortuous vessels prohibits them from being candidates. In addition to these procedures which attempt to reopen or bypass the coronary vessels, direct myocardial revascularization has been performed by inducing the creation of new channels, other than the coronary arteries themselves, to supply oxygenated blood and remove waste products from the heart tissue. Myocardial revascularization is a technique used to supplement the blood supply delivered to the heart by providing the ischemic inner surface of the heart, known as the endocardium, with direct access to the blood within the ventricular chamber. Typically the endocardium receives its nutrient blood supply entirely from the coronary arteries that branch through the heart wall from the outer surface known as the epicardium. 
     In an article entitled “New Concepts In Revascularization Of Myocardium” by Mirhoseini et al. in Ann. Thor. Surg., 45: 415-420, April, 1988 the work of investigators exploring several different approaches for direct revascularization of ischemic myocardium is discussed. One revascularization technique utilizes “myoepexy”, which consists of roughening of the myocardial surface to enhance capillarization. Another technique, known as “omentopexy”, consists of sewing the omentum over the heart to provide a new blood supply. Another approach involves implanting the left internal mammary artery directly into heart muscle so that blood flowing through the side branches of the artery will perfuse the muscle. 
     Similar revascularization techniques have involved the use of polyethylene tubes, endocardial incisions, and the creation of perforated or bored channels with various types of needles, and needle acupuncture. For example, T-shaped tubes have been implanted in the muscle, with the leg of the T-tube extending into the ventricular cavity as reported by Massimo et al. in an article entitled “Myocardial Revascularization By A New Method of Carrying Blood Directly From The Left Ventricular Cavity Into The Coronary Circulation” appearing in J. Thorac. Surg., 34: 257-264, August, 1957. In an article entitled “Experimental Method For Producing A Collageral Circulation To The Heart Directly From The Left Ventricle” by Goldman et al. in the Journal of Thoracic and Cardiovascular Surgery, 31: 364-374, March, 1965, several experimental methods for myocardial revascularization are described. One method involved the implantation of excised perforated carotid arteries into the left ventricular wall. Goldman et al. also examined the use of implanted perforated polyethylene tubing in a similar fashion. 
     Needle acupuncture approaches to direct myocardial revascularization have been made and were based upon the premise that the heart of reptiles achieve myocardial perfusion via small channels between the left ventricle and the coronary arterial tree as described by Sen et al. in their article entitled “Transmyocardial Acupuncture: A New Approach To Myocardial Revascularization” in the Journal of Thoracic and Cardiovascular Surgery, 50: 181-187, August, 1965. In that article it was reported that researchers attempted to duplicate the reptilian anatomy to provide for better perfusion in human myocardium by perforating portions of the ventricular myocardium with 1.2 mm diameter needles in 20 locations per square centimeter. It has been shown that the perfusion channels formed by mechanical methods such as acupuncture generally close within two or three months due to fibrosis and scarring. As a result these types of mechanical approaches have been abandoned in favor of the use of lasers to effect the transmyocardial revascularization (TMR). 
     U.S. Pat. No. 5,591,159 (Taheri) describes a device for effecting myocardial perfusion that utilizes slit needles to perforate the myocardium. The needles may also utilize a laser beam directed through the lumens of the needles. The device uses a trans-femoral approach to position the device into the left ventricle of the patient. A plunger is activated to cause the needles to enter the myocardium several times. Perforation of the myocardium may be effected by means of a laser beam through the lumen of the needle or high velocity drill. 
     U.S. Pat. No. 5,655,548 (Nelson et al.) describes a method for perfusing the myocardium using a conduit disposed between the left ventricle and the coronary sinus. In one method, an opening is formed between the left ventricle and the coronary sinus, and the coronary ostium is partially occluded using a stent that prevents the pressure in the coronary sinus from exceeding a predetermined value. Blood ejected from the left ventricle enters the coronary sinus during cardiac systole. The apparatus limits the peak pressure in the coronary sinus to minimize edema of the venous system. The system utilizes retroperfusion via the coronary since of the venous system. 
     Previous researchers had explored long term retroperfusion via the coronary sinus but found that it leads to edema of the cardiac veins which are incapable of sustaining long-term pressures above about 60 mm Hg. The procedure basically places a stent-like plug in the left ventricle so that blood flows into the coronary sinus and then into the myocardium via the venous system using retroperfusion, not into the myocardium directly. In the aforementioned Nelson et al. patent there is disclosed the use of a cutting instrument, such as a cannulated needle, a rotating blade, or medical laser to provide the required opening for the conduit. It is believed that when implanted in the heart, the plug and stent will result in long-term retrograde perfusion of the myocardium using the cardiac venous system and will cause a redistribution of the flow within the venous system so that a greater fraction of the deoxygenated blood will exit through the lymphatic stem and the Thebasian veins. The inventors also describe the use of a conduit which takes the place of the coronary sinus. 
     U.S. Pat. No. 4,658,817 (Hardy) describes a surgical carbon dioxide laser with a hollow needle mounted on the forward end of the handpiece. The needle is used to perforate a portion of the tissue, for instance the epicardium, to provide the laser beam direct access to distal tissue of the endocardium for lasering and vaporization. The device does not vaporize the tissue of the outer wall instead it separates the tissue which recoils to its native position after the needle&#39;s removal. This technique eliminates surface bleeding and the need for suturing the epicardium as is done with other techniques. 
     In U.S. Pat. No. 5,607,421 (Jeevanandam) discloses that laser channels remain open because carbonization associated with the laser energy inhibits lymphocyte, macrophage, and fibroblast migration. Thus, in contrast to channels created by needle acupuncture, laser channels heal more slowly and with less scar formation which allows endothelialization and long term patency. 
     It has been reported by Moosdorf et al. in their article entitled “Transmyocardial Laser Revascularization—Morphologoic Pathophysiologic And Historical Principles Of Indirect Revascularization Of The Heart Muscle” in Z Kardiol, 86(3): 147-164, March, 1997 that the transmyocardial laser revascularization results in a relevant reduction of clinical symptoms such as angina and an increase of exercise capacity in approximately two thirds of the patients treated. Objective data of enhanced myocardial perfusion as assessed by positron emission tomography, thallium scans, and stress echocardiography has also been presented in other studies. Some researchers have found that TMR channels created by CO.sub.2 lasers are surrounded by a zone of necrosis with an extent of about 500 microns. In heart patients who died in the early postoperative period (1 to 7 days) almost all channels were closed by fibrin clots, erythrocytes, and macrophages. At 150 days post procedure, they observed a string of cicatricial tissue admixed with a polymorphous blood-filled capillary network and small veins, which very rarely had continuous links to the left ventricular cavity. At the 2 week post procedure point a granular tissue with high macrophage and monocyte activity was observable. See for example, the article by Krabatsch et al. entitled “Histological Findings After Transmyocardial Laser Revascularization” appearing in J. Card. Surg. 11: 326-331, 1996, and the article by Gassler et al. entitled “Transmyocardial Laser Revascularization. Historical Features in Human Nonresponder Myocardium” appearing in Circulation, 95(2): 371-375, Jan. 21, 1997. 
     In summary, there are a number of potential mechanisms which individually or in combination may be responsible for the improvements seen in patients subject to the previously described myocardial revascularization techniques including: (1) new blood flow through created channels, (2) angiogenesis (stimulation of the creation of new blood vessels), (3) cardiac denervation, (4) the placebo effect, and (5) ablation of ischemic myocardium. 
     Currently it is believed that cardiac denervation and angiogenesis are the primary causes for post procedure angina relief and improved perfusion respectively. The injury stimulates vasculargenesis and the laser energy damages nerves thereby minimizing the pain sensation. The lasers are however very expensive to purchase. 
     While the aforementioned techniques and methods for revascularizing the myocardium offer some promise they nevertheless suffer from one disadvantage or another. 
     OBJECTS OF THE INVENTION 
     Accordingly, it is a general object of this invention to provide a transmyocardial revascularization system which overcomes the disadvantages of the prior art. 
     It is a further object of this invention to provide a system and methodology for providing relief from ischemic myocardium. 
     It is a further object of this invention to provide apparatus and methods for providing myocardial perfusion that reduce the level of ischemia in a patient. 
     It is a further object of this invention to provide methods and apparatus for myocardial revascularization to reduce the level of discomfort associated with angina in a patient. 
     It is a further object of this invention to provide a device and method to enable patients that suffer from the later stages of ischemic heart disease to experience reduced pain and improved emotional well-being. 
     It is a further object of this invention to provide a transmyocardial revascularization system and methodology which is simple and cost effective. 
     It is a further object of this invention to provide an apparatus and method for myocardial revascularization to increase blood flow to the myocardium from the endocardium without using the native diseased coronary arteries. 
     It is a further object of this invention to provide an apparatus and method for myocardial revascularization to be used with patients having extensive coronary atherosclerosis in whom a bypass surgery is not indicated. 
     It is a further object of this invention is to provide a device and technique for endovascular myocardial revascularization. 
     It is another object of the present invention to provide methods and apparatus which can be utilized either in open surgical, minimally invasive surgical, or transluminal techniques to perfuse the myocardium. 
     It is a further object of this invention to provide direct myocardial revascularization without the need for opening the chest cavity. 
     It is a further object of this invention to provide direct endovascular myocardial revascularization without having to utilize a laser (although a laser may be used, if desired in some applications as part of the procedure). 
     SUMMARY OF THE INVENTION 
     These and other objects of this invention are achieved by providing a cardiac vascularization system and methods of revascularizing the myocardium. The system basically comprises at least one, and preferably a plurality of elongated small diameter inserts for introduction at spaced locations from one another in the wall of the myocardium. The inserts are formed of a material to elicit a foreign body or healing response to cause the formation of lumens in communication with the arterial system. The inserts may be totally resorbable, partially resorbable or non-resorbable, and in the case of the latter may be removable from the myocardium after the formation of the lumens. 
     In accordance with various preferred embodiments of the invention the system also includes various deployment instruments for deploying the inserts into the wall of the myocardium. Some instruments are arranged to introduce the inserts into the myocardium via either the pericardium, while other instruments are arranged to introduce the inserts into the myocardium via the endocardium. 
     The deployment instruments maybe configured to form the lumens by mechanical action or by the application of energy, e.g., electrical, thermal, sonic, radiation, etc., or some biological agent to the myocardium. The inserts themselves or in combination with deployment instrument can be used to form the lumens. 
     In accordance with one aspect of the invention the system may include means to stabilize the deployment instrument during the formation and/or insertion of the inserts into the myocardium. In addition control means may be provided to coordinate the operation of the deployment instrument with the cardiac cycle. 
    
    
     
       DESCRIPTION OF THE DRAWING 
       Other objects and many attendant features of this invention will become readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein: 
         FIG. 1  is an illustration of the heart of a living human being showing one embodiment of a deployment instrument forming a portion of the myocardial revascularization system of the subject invention being used to deploy plural inserts constructed in accordance with this invention into the myocardium via the pericardium; 
         FIG. 2  is an illustration similar to that of  FIG. 1 , but showing another embodiment of a deployment instrument forming a portion of the myocardial revascularization system of the subject invention being used to deploy those inserts into the myocardium via the epicardium; 
         FIG. 3  is an enlarged illustration of the heart of a living human being showing the inserts of the system of  FIG. 1  in place fully embedded in the wall of the myocardium; 
         FIG. 4  is a side elevational view, partially in section, of an alternative embodiment of an insert and an alternative deployment instrument forming an alternative embodiment of a system constructed in accordance with this invention; 
         FIG. 5  is a side elevational view, partially in section, showing another portion of the deployment instrument of the embodiment of the system shown in  FIG. 4 ; 
         FIG. 6  is a side elevational view, partially in section, showing the deployment of the insert of  FIG. 4  into the wall of the myocardium by the deployment instrument of  FIGS. 4 and 5 ; 
         FIG. 7  is a side elevational view, partially in section, showing the insert of  FIGS. 4-6  when fully deployed in the wall of the myocardium; 
         FIG. 8  is an enlarged isometric view of the distal end of the insert shown in  FIGS. 4-7 ; 
         FIGS. 9A-9S  are each isometric views of respective alternative embodiments of inserts constructed in accordance with this invention; 
         FIGS. 10A-10D  are each side elevation views, partially in section, of various exemplary inserts of the subject invention shown in place within the wall of the myocardium; 
         FIG. 11  is a block and schematic diagram showing one embodiment of the system of the subject invention and including means to control the operation thereof in accordance with the cardiac cycle; 
         FIG. 12  is a diagram like that of  FIG. 11  but showing the addition of a mechanism, e.g., a vacuum hood, for use with a deployment instrument of this invention to stabilize the deployment instrument with respect to the myocardium; 
         FIG. 13  is an illustration of a portion of the wall of a healthy heart showing its vascularity; 
         FIG. 14  is an illustration, like that of  FIG. 13 , but showing a wall whose vasculature has been reduced over time by atherosclerosis, e.g., the branches of its coronary arteries are fully or partially occluded and many of the capillaries in the myocardium have atrophied; 
         FIG. 15  is an illustration, like that of  FIG. 14 , but showing the wall of the heart immediately after deployment of an insert of the system of this invention in the myocardium to increase the flow of blood from the ventricle via the lumen in which the insert is located to tissue and capillaries contiguous with the lumen; 
         FIG. 16  is an illustration, like that of  FIG. 15 , but showing the wall of the heart some time after the deployment of an insert so that the insert has elicited a foreign body response in the myocardium tissue to stimulate angiogenesis and revascularization, whereupon the increased flow of blood in one portion of a vessel can provide added blood to neighboring tissues and capillaries; and 
         FIG. 17  is an illustration, like that of  FIG. 16 , but showing the wall of the heart at some later time (i.e., after the insert has been absorbed or has been removed from its lumen), whereupon the lumen may shrink in diameter but may remain patent to carry blood to contiguous tissue and capillaries, including the recently grown vasculature, to thereby provide a beneficial blood supply to the myocardium. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     Referring now to the drawing where like reference numerals refer to like parts there is shown in  FIG. 1  a transmyocardial revascularization system  20  constructed in accordance with this invention shown in the process of revascularizing the myocardium of a living, e.g., human, being. In  FIG. 13  there is shown, by way of an illustration (not to scale), a section of the wall of the left ventricle of a healthy human heart  1 . As can be seen therein the wall includes the epicardium  2 , the myocardium  3 , the endocardium  4 , two unoccluded branches  5  and  6  of a coronary artery and extensive associated vasculature, e.g., capillaries  7 . In  FIG. 14  the illustration is of the same portion of the wall of the ventricle, but showing the effects of atherosclerosis, i.e., lesions or plaque deposits  8 , in the branch vessels  5  and  6  and atrophied vasculature  7 . 
     The revascularization systems of this invention are particularly suitable for revascularizing the myocardium whose blood supply has been diminished by atherosclerosis (like that shown in  FIG. 14 ) or by other disease processes. Moreover, the subject invention contemplates various different systems and preferred ones of those systems will be described in detail later. Suffice it for now to state that each system constructed in accordance with this invention includes at least one, and preferably, a plurality of elongated inserts  22  (designated by the general reference number  22  in  FIG. 1 ) and a deployment instrument (e.g., instrument  24  of  FIG. 1 ) for deploying the insert(s) into the myocardium. Various alternative inserts  22 A- 22 S are shown in  FIGS. 9A-9S , respectively. 
     In accordance with one preferred embodiment of a system the deployment instrument  24  utilizes a piercing member (to be described later) located adjacent its distal end to create plural channels or lumens  9  ( FIGS. 1 and 15 ) in the wall of the myocardium  3  at spaced locations from one another and into which respective inserts (e.g., inserts  22  of  FIG. 1 ) are deployed. Other means can be utilized to form the channels or lumens  9 . For example the system may include means, e.g., as part of the deployment instrument or some other device, for providing a suitable biological agent to the myocardium and associated tissue (e.g., endocardium or epicardium) to produce or form a lumen in the myocardium. Alternatively, the deployment instrument can provide one or more of various types of energy to that tissue to create the lumen(s) and then the insert(s) can be deployed therein. Examples of various types of energy contemplated for such a procedure are thermal energy, mechanical energy (e.g., rotational cutting or boring, slicing, etc.), electrical energy (e.g., radio frequency energy), hydraulic energy, pneumatic energy, vibratory energy (e.g., sonic, ultrasonic, etc.) radiation energy, laser or other light energy, or other types of electromagnetic energy, etc. It should be pointed out at this juncture that the application of energy to the cardiac tissue not only serves to create the lumen(s)  9  for the insert(s)  22  and  22 A- 22 S, but can also disable local nerves (denervation) to minimize patient pain resulting from angina. 
     It should also be pointed out that the formation of the channels or lumens  9  in the myocardium and associated tissue can be accomplished by means other than the insert-deployment instrument  24 . In this regard the subject invention contemplates that the inserts themselves can be constructed so that they can be used to pierce or otherwise penetrate into the wall of the myocardium to form the lumens. In such applications the formation of the lumens is accomplished at the same time that the inserts are deployed therein. 
     Irrespective of how the lumens  9  are formed, the inserts can be inserted into the wall of the myocardium  3  and into the lumens (or to form the lumens), via either a transthoracic approach to the epicardium  2  (see  FIG. 1 ) or by a percutaneous transvascular, e.g., transfemoral, approach to the endocardium  4  (see  FIG. 2 ). When the lumens are formed by transthoracic approach they are preferably made sufficiently deep to communicate with the interior of the ventricle. However, for some type of myocardial revascularization procedures communication of the lumen with the ventricular chamber is not necessary, as will be described later. 
     When the lumen(s) is(are) in communication with the ventricular chamber and the insert(s) is(are) in place within those lumens, the insert(s) serve(s) to hold the lumen(s) open and allow blood to flow into the lumen(s) from the ventricular chamber, whereupon that blood can nourish tissue and capillaries in the myocardium contiguous with the lumen. 
     In accordance with a preferred aspect of this invention, the inserts are formed of a material so that when they are in place they serve to initiate a “foreign body” or “healing response” in the local (i.e., contiguous) tissue, whereupon the inserts can be removed or absorbed thereafter, leaving the lumens patent to supply blood to contiguous tissue, capillaries and additional vasculature (e.g., new capillaries) which have grown over time by virtue of the process of angiogenesis. This action ensures that the myocardium receives an increased blood supply over that which it received prior to the subject transmyocardial revascularization (TMR) procedure. 
     Even where the lumen(s) formed do not communicate with the interior of the ventricular chamber, its (their) formation and the deployment of the insert(s) therein still has an advantageous effect insofar as providing beneficial blood flow to the myocardium is concerned. In this regard the formation of a lumen and the deployment of an insert therein serves to bridge those capillaries which are contiguous with the lumen. Thus, blood can be carried from capillaries in one portion of the myocardium to capillaries in a remote portion thereof by the lumen bridging those capillaries. In addition, over time the healing response and resultant angiogenesis induced by the presence of the inserts in the lumen will increase the myocardial vasculature, thereby further benefiting the patient. 
     In some applications it may be desirable to stabilize the deployment instrument against the endocardium or epicardium during the revascularization procedure. For such applications the system makes use of some releasable securement or attachment means, such as a suction hood (to be described later) to stabilize or otherwise hold the deployment instrument in place. Once positioned, the instrument can be activated to advance the piercing member or to direct energy into the cardiac tissue to create the lumen and to introduce an insert therein. 
     In some applications, depth control means (also to be described later) may be provided to limit the depth of penetration of the insert(s) into the myocardium. The depth control means may comprise means to limit the depth of the lumen(s) created by the instrument, or may comprise means on the insert itself to limit its depth of penetration into the lumen or may be a combination of both. 
     In some applications, e.g., where the deployment instrument applies electrical energy to the cardiac tissue to form the lumen(s) or where formation of the lumen(s) and/or deployment of the insert(s) therein is best accomplished during a particular portion of the cardiac cycle, the system may also include some control and sensing means (also to be described later) that synchronizes the operation of the deployment instrument to a specific portion of the cardiac cycle. 
     As will also be described later, the inserts  22  and  22 A- 22 R are of various shapes, e.g., solid, tubular, trough-like, helical (spring-shaped), filament, or ribbon-like members, etc. They may be of any suitable biocompatible material, and may be formed of one or more resorbable materials so as to be either partially or totally resorbable. Examples of suitable resorbable materials are polyglycolic acid, polydiaxonone, polycaprolactone, collagen, hyaluronic acid, a polymer composite and/or oxidized regenerated cellulose. 
     Referring again to  FIG. 1  the details of the system  20  as shown therein will now be discussed. As mentioned earlier that system comprises a deployment instrument  24  and plural inserts  22 . The instrument  24  itself basically comprises an elongated central wire  26  having pointed or otherwise sharp distal end or piercing tip  28 . A flange  30  projects outward from the periphery of the wire  26  a short distance proximally of the tip  28 . The insert  22  is a tubular member which is arranged to be disposed and frictionally held on the wire  28  between the flange  30  and the tip  28  so that it can be carried by the wire  26  into the epicardium and underlying myocardium by the application of a force in the distal direction on the wire. In this regard the proximal end (not shown) of the wire  28  is coupled to means (also not shown) arranged to have a pushing force applied thereto by either manual action or by some component, e.g., a motor or other actuator, under control of a control system  52 , like that shown in  FIG. 11 . This pushing action causes the tip  28  of the wire  26  to pierce through the epicardium and underlying myocardium to form a lumen  9  with further advancement of the wire  26  in the distal direction carrying the insert into the lumen  9 . 
     As mentioned above, the embodiment of the insert shown in  FIG. 1  and designated by the reference number  22  basically comprises a small diameter, elongated tubular member. That member is similar to the insert shown in  FIG. 9A , and as best seen therein has a central channel or passageway  32  through which the wire  26  may pass when the insert is mounted thereon. The insert also includes plural apertures  34  in the wall forming it and which are in fluid communication with the passageway  32 , for the reasons to be described later. An optional flange may be provided about the periphery at the proximal end  36  of the tubular insert as shown in  FIG. 9A . The flange serves as a stop to engage cardiac tissue to preclude the insert from being inserted too deep into the myocardium. Insert  22  does not include the flange. The distal end  38  of insert  22  is open and is in communication with the passageway  32 . 
     The insert  22  may be formed of any of the aforementioned resorbable materials so that it will be absorbed over time leaving a lumen  9  like that shown in  FIG. 17 . Alternatively it may be formed of a non-resorbable material. In that case it may be preferable that the insert be removable after some time to leave a lumen  9  like shown in  FIG. 17 . 
     When the insert  22  is located on the deployment instrument&#39;s wire  26  its proximal end  36  ( FIG. 9 ) is in abutment with the flange  30  on the wire and with the piercing tip  28  of the wire extending out of the distal end  38  of the insert as shown in  FIG. 1 . As mentioned above, the proximal end of the wire  26  is coupled to means to have a pushing force applied thereto manually or under control of a control system  52  like that shown in  FIG. 11  or  12 . This pushing action causes the tip  28  of the wire  26  to pierce through the epicardium and underlying myocardium to start to form a lumen  9 . At the same time the flange  30  on the wire abuts the proximal end  36  of the insert to push the insert along with it to carry the insert into the lumen  9  as it is formed. The stop on the insert (if incorporated into the insert) or the flange  30  of the wire  26  is arranged to enable the proximal end of the insert to pass through the epicardium and just slightly into the underlying myocardium and with the length of the insert  22  being selected so that the open distal end  38  of the insert just enters the ventricle. To that end, the length of the insert is preferably selected to be consistent with the thickness of the myocardium into which it is implanted. In order to accommodate various thicknesses of myocardia, the inserts of the subject invention may be pre-cut to any length in the range of approximately 0.6 cm to 2.0 cm in length. Moreover, for typical application the inserts preferably have an outside diameter in the range of approximately 1.5 mm to 2.5 mm and an inside diameter in the range of approximately 1.0 to 2.0 mm. 
     In order to stabilize the deployment instrument  24  during the lumen forming-insert deployment procedure, the device  24  of the system maybe constructed like shown in  FIGS. 1 and 12  to include a releasably securable attachment mechanism in the form of a suction hood  40  and associated components. The suction hood  40  basically comprises an elongate tube  42  having a central passageway  44  for accommodating the insert deployment wire  26  with the insert  22  mounted on the distal end thereof. An enlarged flange  46  extends about the periphery of the distal end of the tube  42  for engagement with the epicardium. A source of vacuum  48  ( FIG. 12 ) is coupled to the proximal end of the tube  42 . The vacuum source is arranged to be actuated by operation of the operator control  50  ( FIG. 12 ). This action couples the vacuum source  48  to the interior of the tube  42  to produce suction at the distal end of the hood to hold the hood in place on the pericardium centered over the location at which an insert is to be deployed. The operator control  50  can then be activated to cause the control system  52  and its various components to operate to effect the pushing of the deployment instrument&#39;s wire  26  (with the insert  22  mounted thereon) distally into the epicardium and underlying myocardium, as discussed above. 
     If it is desired to time the introduction of the insert  22  into the myocardium to any particular portion of the cardiac cycle, e.g., during diastole, then the system may include use of a cardiac cycle monitor  54  and an associated cardiac sensor  56 . The cardiac sensor  56  can be any suitable conventional device for providing an electrical signal indicative of the cardiac cycle. The cardiac cycle monitor is responsive to the sensor for providing signals to the control system  52 , which controls the operation of the deployment instrument in coordination with the sensed cardiac cycle. Thus, the control system initiates the operation of means in the system, coupled to the wire  26  to push the wire distally at a predetermined point in the cardiac cycle. 
     After each of the inserts  22  has been deployed into the myocardium, the instrument is removed, i.e., the wire  26  extracted, and the insert  22  left in place. Thus, since the distal end  38  of the insert  22  is open and in fluid communication with the interior of the left ventricle blood from the left ventricular chamber can flow into the distal end of the insert and be carried down its central passageway  32  and out through the apertures  34  into the adjacent myocardial tissue and capillaries. Since the proximal end of the insert is preferably located just under the epicardium, when the insertion wire  26  is withdrawn the puncture in the epicardium through which the insertion wire passed will close off and hemostasis will occur shortly thereafter. This action will prevent the leakage of blood out of the lumen  9  through the epicardium. 
     As will be appreciated by those skilled in the art the shape of the insert  22  (as well as all of other inserts of this invention) will keep the lumen  9  in which it is located open to the flow of blood therethrough. Over time the body&#39;s natural healing response to the “foreign” insert deployed within the lumen  9  will result in increased vasculature contiguous with the lumen, like shown in  FIG. 17 . It should be noted that in  FIG. 17  the relevant cardiac portion is shown after the insert has either been absorbed or removed, but the result is the same, namely, the formation of new capillaries and vessels as a result of the body&#39;s natural healing response and angiogenesis caused by the one-time presence of the insert within the lumen. 
     In  FIGS. 15-17  the revascularization of the myocardium of an atherosclerotic diseased heart is illustrated. In particular, in  FIG. 16  there is shown the same portion of the heart shown in  FIG. 14 , and described earlier, but after a lumen  9  has been formed in the myocardium and an alternative embodiment of an insert located within that lumen. The alternative insert is the embodiment of the insert shown in  FIG. 9M  and designated by the reference number  22 M. The details of this insert will be described later. Suffice it for now to state that insert  22 M is in the form of a cylindrical coil or helix and has been inserted a lumen  9  formed in the same manner as described earlier. Since the insert  22 M is a helix, it will hold the lumen  9  open and in communication with the interior of the ventricle at its distal end. Moreover, blood can flow into the lumen through the center of the insert  22 M and out through the spaces between contiguous coils to feed the contiguous myocardial tissue and capillaries. On the short term any capillaries which receive blood from the lumen  9  can carry that blood to remote locations, thereby nourishing the tissue at such remote locations by the delivery of more blood thereto than prior to the procedure. Over time the body&#39;s natural healing response and angiogenesis will result in increased vasculature, such as shown in  FIG. 16 . 
       FIG. 17  shows the condition after angiogenesis has occurred to create significant new vasculature, e.g., capillaries  7 , and the insert  22  either has been removed or resorbed by the body. The resorption or removal of the insert from the lumen, so that the insert is no longer present to hold the lumen open, may permit the lumen to shrink or otherwise decrease somewhat in diameter, as illustrated in  FIG. 17 , or eventually close. Even if the lumen  9  eventually closes there will still be some beneficial effect since the tissue contiguous with the lumen  9  will be more highly vascularized than prior to the insertion of the insert due to the elicited angiogenesis. 
     As should be appreciated from the foregoing whether the system  20  makes use of non-resorbable or resorbable inserts is of little relevance from the standpoint of immediately increased blood flow to the myocardium tissue and capillaries contiguous with the lumens so long as the inserts are constructed to enable blood to flow therethrough or therearound in the lumens from the interior of the ventricular chamber. If, however, the inserts are constructed so that they do not allow blood to flow therethrough or therearound within the lumens, then the beneficial effects, e.g., increased vasculative, of the inserts will not likely arise until after they have induced the natural healing response in the myocardium and have been absorbed or otherwise removed from the myocardium. 
     It should be pointed out at this juncture that for some applications the inserts may be constructed so that they do not extend into communication with the ventricular chamber to permit blood to flow from the ventricle into the lumen. One such alternative arrangement is shown in  FIG. 3 . In that illustration the inserts  22  are shown as being fully located (embedded) within the myocardium. Since there will be no blood flow into the lumens from the ventricular chamber, this arrangement will not serve to immediately increase the amount of blood available to the myocardium tissue in which the inserts  22  are located. However, if the inserts are constructed so that blood can flow either through them (e.g., the include a longitudinal passageway and sidewall apertures like those described earlier, or are porous, etc.) or around them within the lumen, then blood from tissue and/or capillaries contiguous with one portion of the lumen  9  can be carried to other portions of the lumen and the tissue and capillaries contiguous therewith. Thus, the presence of the inserts in the lumens may serve to bring blood from one portion of the myocardium to other portions. Moreover, the angiogenesis action resulting by the location of the inserts within the lumens over time will further revascularize the myocardium. 
     In  FIG. 2 , a system  100  constructed in accordance with this invention is shown during the process of revascularizing the myocardium via a transvascular access to the endocardium and myocardium. The system  100  comprises a small diameter, flexible deployment instrument  102  and one or more inserts constructed like those described heretofore. In particular, in the example shown in  FIG. 2 , the inserts used are the inserts  22 . The instrument  102  comprises an outer tube or catheter  104 , an inner tube  106 , and a flexible wire  108 . The wire  108  has a pointed distal end or piercing tip  110 . The catheter  104  includes a central passageway  112  extending down its length and terminating at a free end in the form of a rounded or non-sharp tip  114 . The inner tube  106  is disposed within the passageway  112  and is movable longitudinally with respect to the catheter  104 . The inner tube  106  includes a central passageway through which the wire  108  extends, with the tip  110  of the wire extending beyond the free end  116  of the inner tube by a distance just slightly greater than the length of an insert  22 . 
     The insert  22  is located on the extending portion of the wire  108  as shown in  FIG. 2 . When introduced through the vascular system and into the heart the inner tube  106  and wire  108  are fully retracted within the catheter  104  but located adjacent its tip  114 . The rounded tip  114  of the catheter serves as the end of the instrument  102  to facilitate its safe guidance to the operative position shown in  FIG. 2 . At that time the inner (pusher) tube  106  with the  108  extending therethrough is pushed distally by some means, e.g., manually or by some activator forming a portion of the control system  52 , so that the wire&#39;s tip  110  penetrates through the endocardium and into the myocardium. The continued pushing action forms the lumen and carries the insert into the lumen  9  in a similar manner as described earlier. When the insert is in the desired position within the myocardium the wire  108  is retracted with respect to the inner tube  106  until it no longer is within the insert, thereby depositing the insert within the lumen  9 . The instrument can then be used to deploy other inserts  22  in the same manner, and once all have been deployed the instrument is retracted as a unit from the heart and out of the associated vascular access path. 
     In  FIGS. 4-8  there is shown another alternative system  200  ( FIG. 5 ) for effecting the revascularization of the myocardium. The system  200  is of manual type and basically comprises at least one insert  22 R, like that shown in  FIG. 9R , and a manually operated deployment instrument  202  for deploying the insert in a lumen in the myocardium. The insert  22 R basically comprises a resorbable suture  204  or other flexible filament having a distal end at which a barbed resorbable anchor  206  is fixedly secured. The anchor includes a rounded distal end  208  ( FIG. 8 ) from which plural fingers  210  project backward. The fingers may be somewhat flexible to facilitate the disposition of the insert within the instrument  202  (as will be described later). 
     The instrument  202  basically comprises a pusher member  212  and a piercer member  214 . The pusher member  212  is in the form of a small diameter tube having a tapered distal end  216 , a flanged proximal end  218  forming a cap, and a central passageway  220  extending therebetween. The suture or filament portion  204  of the insert  22 R is located within the passageway  220 , with the anchor  206  being located immediately distally of the tapered distal end  216  of the pusher as shown in  FIG. 4 . 
     The piercer member is a small diameter tube having a bias-cut distal end to form a piercing tip  224 , a flanged proximal end forming a handle  226 , and a central passageway  228  extending therebetween. The entrance to the passageway  228  is flared at  230 . The inside diameter of the passageway  228  is slightly greater than the outside diameter of the pusher member  204  so that the pusher member can be located therein, with the fingers  210  of the anchor position  206  of the insert  22 R flexed radially inward to enable the anchor to fit within the passageway  228  as shown in  FIG. 5 . 
     The instrument  202  is particularly suitable for transthoracic introduction into the myocardium  3 . To that end the instrument  202  is assembled as shown in  FIG. 5  and manipulated (i.e., pushed distally) such that the needle&#39;s piercing tip  224  pierces the epicardium  2  and enters to a desired depth into the myocardium  3  to form a lumen  9 . As shown in  FIG. 6  the depth of penetration is less than the thickness of the myocardium so that the lumen  9  is not in communication with the interior of the ventricular chamber (although it could extend therein, if desired). Stop means (not shown) forming a portion of the instrument  202  can be provided to establish the desired depth of cardiac penetration. 
     Once the piercer member is at the desired depth, the cap  218  of the pusher member is pushed distally with respect to piercer member&#39;s handle  226  to extend the insert&#39;s anchor  206  into the lumen tract, whereupon the freeing of the anchor&#39;s fingers  210  allows them to flex outwardly as shown in  FIG. 6 . The pusher member  212  and the piercer member  214  are then withdrawn as a unit proximally, so that the filament portion  204  is freed leaving the insert in place like shown in  FIG. 7 . The anchor or the insert serves to secure it within the lumen  9  resistant to accidental dislodgment during the deployment procedure. It should be pointed out that the anchor can take various forms, e.g., be a rigid barb-like member lacerated on the outer portion of the insert or it can be an activatable pivoting member (not shown) similar in construction to that used on a conventional clothing label tag, or any other suitable construction. 
     The filament portion  204  may consist of a solid filament, such as a PGA suture, or a strip of material, such as collagen or Gelfoam, or may be non-resorbable, like Gortex. In any case the material for the filament portion  204  is selected to initiate a foreign body reaction to stimulate arteriogenesis in a manner similar to that described earlier. 
     It must be pointed out at this juncture that each insert of this invention is preferably configured such that its, presence in the myocardial tissue does not significantly limit the contractility of the cardiac muscle, although as will be described later some embodiments provide less resistance to cardiac contractility than others. Moreover, the inserts may be coated with or contain growth factors, anti-oxidants, seeded cells, or other drug biologically active components depending upon the result desired. 
     Referring now to  FIGS. 9A to 9S , the details of other inserts constructed in accordance with this invention will be described. These inserts are merely exemplary of many other inserts which can be constructed to accomplish the ends of this invention. 
     The embodiment of the insert  22 A shown in  FIG. 9A  is a tubular structure with axial perforations  34  for allowing blood to pass through the longitudinal passageway  32  and to pass through the lateral perforations  34  into the adjacent myocardium. 
     The embodiment of the insert  22 B shown in  FIG. 9B  is a trough-like structure  60  with slots  62  in the marginal edges to form fins for holding the lumen  9  open. The slots  62  allow more contact of the blood to the neighboring myocardium. The tip  64  is sharpened to facilitate the deployment, e.g., it helps pierce the cardiac tissue during deployment. 
     The embodiment of the insert  22 C shown in  FIG. 9C  is a simple trough-like structure  66 , that is relatively easy to manufacture, e.g., can be made by die cutting a rectangular sheet and forming the sheet around a pin. 
     The embodiment of the insert  22 D shown in  FIG. 9D  comprises a porous walled tube  68 , with a longitudinal passage  70  extending down its center and whose distal end  72  is open. 
     The embodiment of the insert  22 E shown in  FIG. 9E  is a series of tubular cylindrical sections  74  that are connected by flexible filaments  76 . This structure effectively stents the lumen opening and allows the insert to freely contract and expand along the longitudinal axis and therefore conform to the contraction of the myocardium during the cardiac cycle. 
     The embodiment of the insert  22 F shown in  FIG. 9F  is formed of several spherical beads  78  spaced on a flexible filament  76 . The filament also incorporates a T-shaped distal end in the form of anchor member  82  to aid in placement or securement. This insert also effectively stents the lumen and allows the insert to freely contract and expand along the longitudinal axis and therefore conform to the contraction of the myocardium during the cardiac cycle. 
     The embodiment of the insert  22 G shown in  FIG. 9G  is similar to that shown in  FIG. 9F  except that the periodically spaced barb structures  82  extend outward from the filament  80  at spaced locations. This arrangement may better anchor the insert in the myocardium and may also allow for better fluid communication past each barb structure along the length of the lumen  9  than the embodiment  22 F of  FIG. 9F . 
     The embodiment of the insert  22 H shown in  FIG. 9H  is a cylindrical porous material tube  68  with a proximal end in the form of a shoulder  84  to limit penetration. This particular embodiment appears best suited for insertion from the endocardium into the myocardium, whereupon the shoulder  84  anchors the opening of the insert at the ventricle. 
     The embodiment of the insert  22 I in  FIG. 9I  is a flexible woven tube  86  having plural equidistantly spaced reinforcing rings  88 . The woven portions of the tube are porous to allow blood to pass from the inner passageway  90  for communication with the blood vessels and capillaries contiguous with the other lumen  9 . The reinforcing rings  88  support the insert and the adjacent myocardium to keep the lumen from collapsing. 
     The embodiments of the inserts  22 J,  22 K, and  22 L shown in  FIGS. 9J ,  9 K and  9 L, respectively, consist of flexible ribbon-like structures  22  with anchors  94 ,  96 , and  98 , respectively, on the distal end for locating and securing the inserts into the myocardium. The ribbon-like material can be formed of materials such as woven dacron, polyglycolic acid, cotton, silk, and collagen. The ribbon-like tail of these embodiments can be made extra long and after implantation during a surgical approach whatever portion extends from the epicardium can be trimmed off (see  FIG. 10B ). The anchor portion can be formed by insert molding the anchor component onto the filament structure. The main feature of these constructions is to stimulate a foreign body reaction and a healing response which results in the formation of capillaries at the site of the implant. As such, these structures will provide less of a short term improvement to vascularization, but instead will lead to a long term improvement. 
     The embodiment of the inserts  22 M,  22 N, and  22 O shown in  FIGS. 9M ,  9 N, and  9 O, respectively, consists of helical coil-like structures  120 . The implants can be formed of such materials as stainless steel, nitinol, titanium or such material as polyglycolic acid or polylactic acid. The embodiments are flexible, particularly with respect to their longitudinal axis and as such will readily deform longitudinally in conjunction with the cardiac cycle of the myocardium. These structures serve to stent the lumen  9  and allow for excellent fluid communication between the lumen  9  and the adjacent blood vessels. The embodiments shown in  9 N and  9 O have anchoring portions at their respective distal ends which can be used to locate and secure the inserts in the myocardium. In particular, the insert  22 N includes a hook-like member  122  at its distal end, whereas the insert  220  includes a plate-like anchor  124  at its distal end. 
     The embodiment of the insert  22 P shown in  FIG. 9P  is a flexible filament-like member  126  with a stiffened distal end portion bent back over itself for anchoring the insert into the myocardium. This insert functions in a similar manner to the inserts of embodiments  22 J,  22 K and  22 L. 
     The embodiment of the insert  22 Q shown in  FIG. 9Q  is a perforated cylinder member, similar to insert  22 A but with tongue-like member  130  at the proximal end of the cylinder to form a shoulder. The shoulder serves to limit the depth of placement of the insert into the myocardium. This particular embodiment is particularly suited to being placed through the epicardium into the myocardium. The bulbous portion of the shoulder limits the depth of penetration into the myocardium and the epicardium seals around it to prohibit leakage from the channel past the epicardium like shown in  FIG. 10D . 
     The embodiment of the insert  22 R shown in  FIG. 9R  has been described earlier. This insert  22 R functions in a similar manner to inserts  22 J,  22 K and  22 L. Moreover, the filament-like tails of these embodiments can be made extra long to be trimmed off in a similar manner to that described earlier with reference to inserts  22 J,  22 K and  22 L. The filament can be formed of Dacron, polyester, silk, polyglycolic acid, collagen, or some other such suitable material. The main feature of these constructions is to stimulate a foreign body reaction and a healing response which results in the formation of capillaries at the site of the implant. As such, these structures will provide less of a short term improvement to vascularization, but instead will lead to a long term improvement. 
     The embodiment of the insert  22 S shown in  FIG. 9S  is a “flowable” insert comprised of a flowable material  132 , such as collagen paste, cyanoacrylate (glue/adhesive), thrombin glue, growth factor gelatin, etc. The flowable material can be stored in a tube (not shown) and dispensed into the puncture tract by a needle-like device, such as a syringe (not shown). The flowable material can be designed to harden slightly after placement, like an epoxy or silicon caulking material, so that it is not extruded from the puncture during the cardiac contraction cycle. A main feature of this construction is to stimulate a foreign body reaction and a healing response which results in the formation of capillaries at the site of the implant. As such, the insert  22 S will provide less of a short term improvement to vascularization, but instead will lead to a long term improvement. 
     In  FIGS. 10A to 10D  various of the inserts described above are shown in place in the myocardium to cause the body to initiate a healing response in tissue contiguous with the lumen, as described heretofore. The tissue at which the foreign healing response occurs at initially is designated by the reference number  11  in those figures. While not shown in  FIGS. 10A-10D , additional or new vasculature results in the myocardial tissue as a result of angiogenesis. 
     Without further elaboration the foregoing will so fully illustrate our invention that others may, by applying current or future knowledge, adopt the same for use under various conditions of service.