US20020022857A1 - Medical grafting methods and apparatus - Google Patents

Abstract

Methods and apparatus for delivering and installing a new length of tubing between two sections of a patient's existing body organ tubing and at least partly outside of that existing structure. For example, the new length of tubing may be for the purpose of providing the patient with a coronary bypass. The new tubing may be an artificial graft, a natural graft (harvested elsewhere from the patient), or both. The new tubing is delivered to and installed at the operative site primarily by working through the patient's existing tubular body organ structure. This avoids the need for any significant surgery on the patient. The artificial grafts may have shapes other than tubular. Certain procedural and apparatus aspects of the invention have uses other than in connection with grafting in general or tubular grafting in particular.

Description

• This is a continuation of application Ser. No. 09/323,181, filed May 28, 1999, which was a continuation of application Ser. No. 08/745,618, filed Nov. 7, 1996 (now U.S. Pat. No. 5,976,178), both of which prior applications are hereby incorporated by reference herein in their entireties.[0001]
BACKGROUND OF THE INVENTION
• This invention relates to grafts for use in the repair, replacement, or supplement of a medical patient's natural body organ structures or tissues. The invention also relates to methods for making graft structures. The invention further relates to methods and apparatus for delivering a graft to an operative site in a patient, and for installing the graft at that site. Some aspects of the invention may have other uses such as for viewing the interior of a patient, providing access to the interior of a patient for other procedures, etc. An example of the possible uses of the invention is a minimally invasive cardiac bypass procedure. This example will be considered in detail, but it will be understood that various aspects of the invention have many other possible uses.[0002]
• Several procedures are known for revascularizing the human heart in order to treat a patient with one or more occluded coronary arteries. The earliest of these procedures to be developed involves exposing the heart by means of a midline sternotomy. Following surgical exposure of the heart, the patient's aorta and vena cava are connected to a heart/lung machine to sustain vital functions during the procedure. The beating of the heart is stopped to facilitate performance of the procedure. Typically, a suitable blood vessel such as a length of the patient's saphenous (leg) vein is harvested for use as a graft. The graft is used to create a new, uninterrupted channel between a blood source, such as the aorta, and the occluded coronary artery or arteries downstream from the arterial occlusion or occlusions.[0003]
• A variation of the above procedure involves relocating a mammary artery of the patient to a coronary artery.[0004]
• Although the above-described sternotomy procedures are increasingly successful, the high degree of invasiveness of these procedures and the requirement of these procedures for general anesthesia are significant disadvantages. Indeed, these disadvantages preclude use of sternotomy procedures on many patients.[0005]
• More recently, less invasive procedures have been developed for revascularizing the heart. An example of these procedures is known as thoracostomy, which involves surgical creation of ports in the patient's chest to obtain access to the thoracic cavity. Specially designed instruments are inserted through the ports to allow the surgeon to revascularize the heart without the trauma of a midline sternotomy. Drugs may be administered to the patient to slow the heart during the procedure. Some thoracostomy procedures involve relocating a mammary artery to a coronary artery to provide a bypass around an occlusion in the coronary artery.[0006]
• Thoracostomy bypass procedures are less traumatic than sternotomy bypass procedures, but they are still too traumatic for some patients. Also, the number of required bypasses may exceed the number of mammary arteries, thereby rendering thoracostomy procedures inadequate to fully treat many patients.[0007]
• Another technique for revascularizing the human heart involves gaining access to the thoracic cavity by making incisions between the patient's ribs. This procedure is known as thoracotomy. It is also substantially less traumatic than midline sternotomy, but it is still too traumatic for some patients.[0008]
• In view of the foregoing, it is an object of this invention to provide less traumatic methods and apparatus for revascularizing a patient.[0009]
• It is another object of the invention to provide minimally invasive methods and apparatus for repairing, replacing, or supplementing the blood vessels or other body organ tubing or tissues of a patient.[0010]
• It is still another object of the invention to provide improved graft structures for use in the repair, replacement, or supplementing of natural body organ structures or tissues, and to provide methods for making such graft structures.[0011]
• It is yet another object of the invention to provide improved methods and apparatus for transporting or delivering and installing graft structures for use in the repair, replacement, or supplementing of natural body organ structures or tissues of a patient.[0012]
SUMMARY OF THE INVENTION
• These and other objects of the invention are accomplished in accordance with the principles of the invention by providing methods and apparatus for substantially non-surgically installing a new length of tubing in a patient between two sections of the patient's existing body organ tubing, the new length of tubing being delivered to the operative site by passing along existing tubing, but installed at the operative site so that it is at least partly outside the existing tubing. (As used herein, references to a patient's existing body organ tubing or the like include both natural and previously installed graft tubing (whether natural, artificial, or both). A previous installation of graft tubing may have occurred in a previous procedure or earlier in a current and on-going procedure. References to a length of tubing also include plural lengths of tubing.) At one end of the operative site, the new length of tubing is caused to extend out through an opening made in the existing tubing. The outwardly extending end portion of the new tubing is guided to the other end of the operative site. At that other end another opening is made in the existing tubing and the extending end portion of the new tubing is attached to the existing tubing via that opening. The other end portion of the new tubing (remote from the extending portion) is similarly attached to the existing tubing at the first-described opening. The new tubing installation is now complete, and the apparatus used to make the installation can be withdrawn from the patient.[0013]
• In the most preferred embodiment, all or substantially all necessary apparatus is inserted into the patient via the patient's existing body organ tubing. In addition, all or substantially all apparatus functions at the operative site are remotely controlled by the physician (a term used herein to also include supporting technicians) from outside the patient's body.[0014]
• Preferred apparatus in accordance with the invention includes a first elongated instrument for extending through the patient's existing body organ tubing to a first end of the operative site, and a second elongated instrument for similarly extending through the patient's existing tubing to a second end of the operative site. Each instrument includes a structure capable of penetrating the existing tubing at the associated end of the operative site. In addition, these structures are capable of interengaging with one another outside the existing tubing to provide a substantially continuous structural path from outside the patient, along the patient's existing tubing, and then outside that tubing from one end to the other of the operative site. This structure is used to guide the new length of tubing into the patient and into position at the operative site.[0015]
• At least one of the elongated instruments preferably includes mechanisms for fastening each end portion of the new length of tubing to the adjacent existing body organ tubing. For example, these mechanisms may activate fasteners on or associated with the new tubing.[0016]
• The new tubing may be artificial graft tubing. Alternatively, the new tubing may be natural body organ tubing (e.g., tubing harvested from another location in the patient's body). As still another alternative, the new tubing may be a combination of artificial and natural tubing (e.g., natural tubing disposed substantially concentrically inside artificial tubing).[0017]
• A preferred form of artificial tubing includes a tube frame of a first highly elastic material (such as nitinol) covered with a second highly elastic material (such as silicone rubber) to substantially fill in the apertures in the frame. This combination produces an artificial graft that is distensible like natural body organ tubing such as a natural artery. The covering on the frame is preferably made porous to a predetermined degree to improve its bio-utility in this context. A preferred method of providing such porosity is to make the covering from an elastic material that is mixed with particles of a material that can be removed (e.g., by vaporization) after the covering has been applied to the mesh. When the particles are removed, voids are left in the covering that give it the desired porosity.[0018]
• The artificial grafts of this invention may be coated (in the case of tubular grafts, on the inside and/or outside) to still further enhance their bio-utility. Examples of suitable coatings are medicated coatings, hydrophylic coatings, smoothing coatings, collagen coatings, human cell seeding coatings, etc. The above-described preferred porosity of the graft covering helps the graft to retain these coatings. Additional advantages of the artificial grafts of this invention are their elasticity and distensibility (mentioned above), their ability to be deployed through tubes of smaller diameter (after which they automatically return to their full diameter), the possibility of making them modular, their ability to accept natural body organ tubing concentrically inside themselves, their ability to support development of an endothelial layer, their compatibility with MRI procedures, their ability to be made fluoroscopically visible, etc.[0019]
• Although grafts in the form of tubing are described above, certain aspects of the invention are equally applicable to other graft procedures and to grafts having other shapes.[0020]
• Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments.[0021]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a simplified longitudinal sectional view showing a portion of an illustrative procedure and related apparatus in accordance with this invention.[0022]
• FIG. 2 is a simplified longitudinal sectional view showing a portion of a more particular illustrative procedure and related apparatus in accordance with the invention.[0023]
• FIG. 3 is a simplified longitudinal sectional view showing an illustrative embodiment of a portion of the FIG. 2 apparatus in more detail.[0024]
• FIG. 3[0025]ais a view similar to FIG. 3 showing an alternative illustrative embodiment of the FIG. 3 apparatus.
• FIG. 4 is a simplified elevational view showing an illustrative embodiment of a portion of the FIG. 3 apparatus in still more detail.[0026]
• FIG. 5 is a simplified longitudinal sectional view showing another portion of an illustrative procedure and related apparatus in accordance with this invention.[0027]
• FIG. 6 is a view similar to FIG. 2 showing a later stage in the illustrative procedure depicted in part by FIG. 2, together with related apparatus, all in accordance with this invention.[0028]
• FIG. 7[0029]ais a simplified longitudinal sectional view of an illustrative embodiment of a portion of the FIG. 6 apparatus in more detail.
• FIG. 7[0030]bis a simplified elevational view of a portion of the FIG. 7aapparatus, but with the depicted elements in a different physical relationship to one another.
• FIG. 7[0031]cis a simplified longitudinal sectional view of an alternative embodiment of one component of the FIG. 7aapparatus.
• FIG. 7[0032]dis a simplified longitudinal sectional view of an alternative embodiment of another component of the FIG. 7aapparatus.
• FIG. 7[0033]eis a simplified elevational view of another alternative embodiment of the component shown in FIG. 7d.
• FIG. 7[0034]fis a simplified elevational view of an alternative embodiment of still another component shown in FIG. 7a.
• FIG. 7[0035]gis a simplified elevational view of an alternative embodiment of yet another component shown in FIG. 7a.
• FIG. 8 is a simplified Longitudinal sectional view similar to a portion of FIG. 6 showing a still later stage in the illustrative procedure depicted in part by FIG. 6.[0036]
• FIG. 8[0037]ais a simplified sectional view of the apparatus shown in FIG. 8 without the associated tissue structure being present.
• FIG. 9 is a simplified cross sectional view of an illustrative embodiment of further illustrative apparatus in accordance with this invention.[0038]
• FIG. 10 is a simplified longitudinal sectional view of an illustrative embodiment of a portion of the FIG. 9 apparatus.[0039]
• FIG. 10[0040]ais a view similar to FIG. 10 showing a possible alternative construction of the FIG. 10 apparatus.
• FIG. 10[0041]bis another view similar to FIG. 10 showing another possible alternative construction of the FIG. 10 apparatus.
• FIG. 10[0042]cis another view similar to FIG. 10 showing still another possible alternative construction of the FIG. 10 apparatus.
• FIG. 11 is a view similar to FIG. 6 showing an even later stage in the illustrative procedure depicted in part by FIG. 8, together with related apparatus, all in accordance with this invention.[0043]
• FIG. 12 is a view similar to a portion of FIG. 11, but in somewhat more detail, showing a still later stage in the illustrative procedure depicted in part by FIG. 11.[0044]
• FIG. 12[0045]ais a view similar to FIG. 12 showing a possible alternative construction of the FIG. 12 apparatus.
• FIG. 13 is a view similar to FIG. 12 showing an even later stage in the illustrative procedure depicted in part by FIG. 12.[0046]
• FIG. 14 is a view similar to FIG. 11 showing a still later stage in the illustrative procedure depicted in part by FIG. 13.[0047]
• FIG. 15 is a simplified longitudinal sectional view of an illustrative embodiment of a portion of still further illustrative apparatus in accordance with this invention.[0048]
• FIG. 15[0049]ais a simplified elevational view of a structure which can be used to provide part of the apparatus shown in FIG. 15.
• FIG. 15[0050]bis a view similar to FIG. 15ashowing more of the structure of which FIG. 15ais a part.
• FIG. 15[0051]cis a view similar to FIG. 15bshowing the FIG. 15bstructure in another operational condition.
• FIG. 15[0052]dis a simplified elevational view of an alternative structure which can be used to provide part of the apparatus shown in FIG. 15.
• FIG. 15[0053]eis a view similar to FIG. 15dshowing the FIG. 15dstructure in another operational condition.
• FIG. 15[0054]fis a simplified longitudinal sectional view of another alternative structure which can be used to provide part of the apparatus shown in FIG. 15.
• FIG. 15[0055]gis a view similar to FIG. 15fshowing the FIG. 15fstructure in another operational condition.
• FIG. 16 is a simplified elevational view of an illustrative embodiment of one component of the FIG. 15 apparatus.[0056]
• FIG. 17 is a simplified longitudinal sectional view of an illustrative embodiment of another portion of the FIG. 15 apparatus.[0057]
• FIG. 18 is a view similar to a portion of FIG. 14 showing an even later stage in the illustrative procedure depicted in part by FIG. 14.[0058]
• FIG. 19 is a view similar to FIG. 18 showing a still later stage in the FIG. 18 procedure.[0059]
• FIG. 20 is a view similar to FIG. 19 showing an even later stage in the FIG. 19 procedure.[0060]
• FIG. 21 is a view similar to another portion of FIG. 14 showing a still later stage in the FIG. 20 procedure.[0061]
• FIG. 22 is a view similar to FIG. 21 showing an even later stage in the FIG. 21 procedure.[0062]
• FIG. 22[0063]ais a view similar to FIG. 22 showing a still later stage in the FIG. 22 procedure.
• FIG. 22[0064]bis a view similar to FIG. 22ashowing an even later stage in the FIG. 22aprocedure.
• FIG. 23 is a view similar to FIG. 22[0065]bshowing a still later stage in the FIG. 22bprocedure.
• FIG. 24 is a view similar to FIG. 23 showing an even later stage in the FIG. 23 procedure.[0066]
• FIG. 25 is a simplified longitudinal sectional view of an illustrative embodiment of a portion of more apparatus in accordance with this invention.[0067]
• FIG. 26 is a view similar to FIG. 20 showing a later stage in the FIG. 24 procedure.[0068]
• FIG. 27 is a view similar to FIG. 26 showing a still later stage in the FIG. 26 procedure.[0069]
• FIG. 28 is a view similar to FIG. 24 showing an even later stage in the FIG. 27 procedure.[0070]
• FIG. 29 is a view similar to FIG. 28 showing a still later stage in the FIG. 28 procedure.[0071]
• FIG. 30 is a view similar to FIG. 29 showing an even later stage in the FIG. 29 procedure.[0072]
• FIG. 31 is a view similar to FIG. 14 showing the end result of the procedure depicted in part by FIG. 30.[0073]
• FIG. 32 is a simplified longitudinal sectional view showing an end result similar to FIG. 31 but in a different context.[0074]
• FIG. 33 is a simplified longitudinal sectional view showing a possible alternative construction of portions of the apparatus showing in FIG. 15.[0075]
• FIG. 34 is a simplified elevational view (partly in section) showing another possible alternative construction of portions of the FIG. 15 apparatus.[0076]
• FIG. 35 is a simplified longitudinal sectional view of the FIG. 34 apparatus in another operating condition.[0077]
• FIG. 36 is a simplified elevational view of apparatus which can be used as an alternative to certain apparatus components shown in FIGS. 15 and 17.[0078]
• FIG. 37 is a simplified elevational view (partly in section) showing additional components with the FIG. 36 apparatus.[0079]
• FIG. 38 is a simplified longitudinal sectional view showing still another possible alternative construction of portions of the FIG. 15 apparatus.[0080]
• FIG. 39 is a simplified elevational view showing in more detail a possible construction of a portion of the FIG. 38 apparatus.[0081]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• Because the present invention has a number of different applications, each of which may warrant some modifications of such parameters as instrument size and shape, it is believed best to describe certain aspects of the invention with reference to relatively generic schematic drawings. To keep the discussion from becoming too abstract, however, and as an aid to better comprehension and appreciation of the invention, references will frequently be made to specific uses of the invention. Most often these references will be to use of the invention to provide a bypass around an occlusion or obstruction (generically referred to as a narrowing) in a patient's coronary artery, and in particular a bypass from the aorta to a point along the coronary artery which is downstream from the coronary artery narrowing. It is emphasized again, however, that this is only one of many possible applications of the invention.[0082]
• Assuming that the invention is to be used to provide a bypass from the aorta around a coronary artery narrowing, the procedure may begin by inserting an elongated instrument into the patient's circulatory system so that a distal portion of the instrument extends through the coronary artery narrowing to the vicinity of the point along the artery at which it is desired to make the bypass connection. This is illustrated by FIG. 1 which shows[0083]elongated instrument100 entering the patient'scirculatory system10 at aremote location12 and passing coaxially along vessels in the circulatory system until itsdistal end portion104 passes through narrowing22 incoronary artery20 and reaches thedownstream portion24 of the artery to which it is desired to make a bypass connection. For example, theentry location12 ofinstrument100 may be a femoral (leg) artery of the patient, a brachial artery of the patient, or any other suitable entry point. It will be appreciated, however, thatentry point12 is typically remote from the location at which the bypass is to be provided, and that control ofinstrument100 throughout its use is from theproximal portion102 that is outside the patient at all times.
• For the illustrative procedure being discussed, FIG. 2 shows a preferred embodiment of[0084]instrument100 in more detail. As shown in FIG. 2,instrument100 may include acatheter tube110 which is inserted (fromlocation12 in FIG. 1) via the patient'saorta30 to the ostium ofcoronary artery20. Anothertubular structure120 is then extended from the distal end ofcatheter110, through narrowing22 tolocation24.
• An illustrative construction of[0085]tubular structure120 is shown in more detail in FIG. 3. There it will be seen thatstructure120 may have twolumens130 and140. Near the distal end ofstructure120,lumen130 communicates with the interior of aninflatable balloon132 on one side ofstructure120, while lumen140 opens out to the opposite side ofstructure120.Lumen140 contains alongitudinal structure150 which may be a stylet wire with a sharpened distal tip152 (see FIG. 4). (Although FIG. 4 shows indentations behindtip152, those indentations could be eliminated if desired.)Structure120 may be provided with adistal spring tip122 to help guide the distal end ofstructure120 alongcoronary artery20 and through narrowing22. A safety ribbon123 (e.g., of the same material as tip122) may be connected at its proximal end to the distal end ofmember120 and at its distal end to the distal end oftip122 to improve the performance oftip122 and to help prevent separation of any portion oftip122 fromstructure120 in the event of damage to tip122.Structure120 may have radiologic (e.g., radio-opaque or fluoroscopically viewable)markers124 at suitable locations to help the physician place the structure where desired in the patient's body.Catheter110 may also haveradiologic markers112 for similar use.Balloon132 is initially deflated.Longitudinal structure150 is initially retracted withinlumen140. However, the distal portion oflumen140 is shaped (as indicated at142 in FIG. 2) to help guide thedistal tip152 ofstructure150 out to the side ofstructure120 whenstructure150 is pushed distally relative to structure120. This is discussed in more detail below. As earlier description suggests, each ofcomponents110,120, and150 is separately controllable from outside the patient, generally indicated asregion102 in FIG. 1.
• As an alternative to providing[0086]balloon132 as an integral part of onestructure120,balloon132 may be provided on anotherlongitudinal structure120′ (FIG. 3a) which is substantially parallel to the remaining components described above forstructure120.Structure120′ may be substantially separate fromstructure120, or it may be attached to structure120.
• After[0087]instrument100 is positioned as shown in FIGS. 1 and 2, a secondelongated instrument200 is similarly introduced into the patient'scirculatory system10 as shown generally in FIG. 5. For example,instrument200 may enter the patient (at14) via a femoral artery, a brachial artery, or any other suitable location, which again is typically remote from the bypass site. If one femoral artery is used to receiveinstrument100, the other femoral artery may be used to receiveinstrument200. Or the same femoral artery may be used to receive both instruments. Or any other combination of entry points may be used for the two instruments.Instrument200 is inserted until its distal end is adjacent to thepoint34 in the circulatory system which it is desired to connect to point24 via a bypass. This is illustrated in a more specific example in FIG. 6 where the distal end ofinstrument200 is shown atlocation34 inaorta30. Theparticular location34 chosen in FIG. 6 is only illustrative, and any other location alongaorta30 may be selected instead.Radiologic markers206 may be provided on the distal portion ofinstrument200 to help the physician position the instrument where desired. Note that FIG. 6 shows portions ofinstruments100 and200 side by side inaorta30.
• An illustrative construction of[0088]instrument200 is shown in more detail in FIG. 7a.This FIG. shows the distal portions ofelements220,230,240, and250 telescoped out from one another and from the distal end ofouter member210 for greater clarity. It will be understood, however, that all of these elements are initially inside of one another and insideouter member210. Indeed,member210 may be initially positioned in the patient without any or all ofelements220,230,240, and250 inside, and these elements may then be inserted intomember210. Moreover, the number of members like220,230, etc., may be more or less than the number shown in FIG. 7a,depending on the requirements of a particular procedure.
• [0089]Outer member210 may be a catheter-type member. The distal portion ofcatheter210 may carry two axially spacedannular balloons212 and214.Proximal balloon212 is inflatable and deflatable viainflation lumen216 incatheter210.Distal balloon214 is inflatable and deflatable viainflation lumen218 incatheter210.Lumens216 and218 are separate from one another so thatballoons212 and214 can be separately controlled.Balloons212 and214 are shown substantially deflated in FIG. 7a.The distal end ofcatheter210 may be tapered as shown at211 in FIG. 7cto facilitate passage ofcatheter210 through an aperture inaorta30 as will be described below.
• Coaxially inside[0090]catheter210 istubular sheath member220.Sheath220 is longitudinally movable relative tocatheter210. The distal portion ofsheath220 may be tapered as shown at222 in FIG. 7d,and/or externally threaded as shown at224 in FIG. 7e.Either or both of features222 and224 may be provided to facilitate passage ofsheath220 through an aperture inaorta30 as will be described below. If threads224 are provided, thensheath220 is rotatable (either alone or with other components) about the longitudinal axis ofinstrument200 in order to enable threads224 to engage the tissue of the aorta wall and help pullsheath220 through the aorta wall.
• Coaxially inside[0091]sheath member220 ispower steering tube230.Tube230 is longitudinally movable relative tosheath220.Tube230 may also be rotatable (about the central longitudinal axis of instrument200) relative tosheath220, and the distal end oftube230 may be threaded on the outside (as shown at232 in FIG. 7f) for reasons similar to those for which threading224 may be provided onsheath220.Tube230 is preferably controllable from its proximal portion (outside the patient) to deflect laterally by a desired amount to help steer, push, ortwist instrument200 to the desired location in the patient.
• Coaxially inside[0092]tube230 istube240.Tube240 is longitudinally movable relative totube230, and may be metal (e.g., stainless steel) hypotube, for example.Screw head242 is mounted on the distal end oftube240 and is threaded (as indicated at244) on its distal conical surface.Tube240 is rotatable (about the central longitudinal axis ofinstrument200, either alone or with other elements) in order rotatehead242 and thereby usethreads244 in engagement with the tissue of the aorta wall to help pullhead242 through that wall as will be more fully described below. Becausetube240 is hollow, it can be used for passage of fluid or pressure into or out of the patient.
• Coaxially inside[0093]tube240 islongitudinal structure250.Longitudinal structure250 is longitudinally movable relative totube240.Structure250 may also be rotatable (about its longitudinal axis) relative totube240 and/or other elements.Structure250 may be a wire with adistal end portion252 that is resiliently biased to deflect laterally to one side.Wire portion252 is kept relatively straight when it is insidetube240 as shown in FIG. 7a.But whenwire portion252 is pushed axially out the distal end oftube240, it curves to one side as shown in FIG. 7b.As an alternative or addition to the above-described resilient lateral deflection, the distal portion ofstructure250 may be threaded as shown at254 in FIG. 7gto help structure250 thread its way through the wall ofaorta30.
• All of[0094]components210,220,230,240, and250 are controlled from outside the patient's body (i.e., fromregion202 in FIG. 5).
• When the distal portion of[0095]catheter210 is at the desiredlocation34,proximal balloon212 is inflated. Even when inflated, proximal balloon is not large enough to blockaorta30.
• After[0096]proximal balloon212 has been inflated,wire250 is pushed distally so that its distal portion emerges from the distal end oftube240 and penetrates the wall ofaorta30 atlocation34. This anchors the distal portion ofinstrument200 to the aorta wall at the desired location. Because of its operation to thus anchorinstrument200,wire250 is sometimes referred to as an anchor wire. The rotatability ofwire250, as well as its resilient lateral deflection (FIG. 7b) and/or threads254 (FIG. 7g), may be used to help get the distal end of the wire to the desiredlocation34 and firmly into the aorta wall at that location in order to achieve the desired anchoring ofinstrument200.
• When[0097]instrument200 is sufficiently anchored bywire250,tubes230 and240 are moved in the distal direction relative to wire250 so thatscrew head242 begins to followwire250 into and through the aorta wall. During this motion, atleast tube240 is rotated about its longitudinal axis so thatthreads244 help to pullhead242 into and through the aorta wall. The distal portion oftube230 followshead242 through the aorta wall. If provided,threads232 and rotation oftube230 may facilitate transfer of the aorta wall tissue fromhead242 totube230.
• When[0098]tube230 is through the aorta wall,sheath220 is moved distally relative totube230 so that a distal portion ofsheath220 followstube230 through the aorta wall. If provided, the distal taper222 and/or threads224 and rotation ofsheath220 help the distal portion ofsheath220 through the aorta wall. Thencatheter210 is advanced distally relative tosheath220 so that a distal portion ofcatheter210 followssheath220 through the aorta wall. Again, thedistal taper211 of catheter210 (if provided) helps the distal portion of the catheter through the aorta wall. Inflatedproximal balloon212 prevents more than just the portion ofcatheter210 that is distal ofballoon212 from passing through the aorta wall.
• It should be mentioned that each time another, larger one of[0099]elements240,230,220, and210 is pushed through the aorta wall, the previously extended elements can be and preferably are either held stationary or pulled back proximally to prevent them from damaging body tissues outside the aorta.
• When the distal portion of[0100]catheter210 is through the aorta wall,distal balloon214, which is now outside the aorta, is also inflated. The axial spacing betweenballoons212 and214 is preferably small enough so that the aorta wall is clamped between these two balloons as shown in FIG. 8. For example, ifballoons212 and214 were inflated without the presence of the aorta wall, their appearance might be as shown in FIG. 8a.The close spacing ofballoons212 and214, as well as their resilient bias toward one another, helps to anchorcatheter210 through the aorta wall and also to seal the aorta wall around the catheter.Balloons212 and214 may be inflated by liquid or gas, and they may be specially coated to help improve the seal betweencatheter210 and the aorta wall.
• After the condition of[0101]catheter210 shown in FIG. 8 has been reached, all ofcomponents220,230,240, and250 can be withdrawn from the patient by pulling them out ofcatheter210 in the proximal direction.
• The next step in the illustrative procedure being described is to insert an elongated, steerable,[0102]endoscopic snare300 lengthwise intocatheter210. A simplified cross sectional view of an illustrative steerable endoscopic snare is shown in FIG. 9. As shown in that FIG.,snare300 includes one or more sheath structures such as310aand310bthat are operable by the physician to steer the snare by curvilinearly deflecting it laterally by a desired, variable amount. Within sheaths310 are such other components as (1) afiber optic bundle320 for conveying light from outside the patient to the distal end ofsnare300 in order to provide illumination beyond the distal end of the snare, (2) anotherfiber optic bundle330 for conveying an image from beyond the distal end of the snare back to optical and/or video equipment outside the patient and usable by the physician to see what is beyond the distal end of the snare, and (3) asnare sheath340 with theactual snare instrument350 inside of it. Additional lumens such as360 may be provided for such purposes as introducing fluid that may help to clear the distal ends of fiber optic bundles320 and330, for introducing fluid for irrigating and/or medicating the patient, for suctioning fluid from the patient, etc. It may not be necessary to provide aseparate snare sheath340, but ratherelement340 may merely be a lumen through thegeneral structure300 forsnare instrument350.
• An illustrative embodiment of the distal portion of[0103]snare instrument350 is shown in FIG. 10. In thisembodiment instrument350 includes awire352 with a snare loop354 (also of wire) at its distal end.Loop354 is closed when it is inside snare sheath orlumen340.Loop354 opens resiliently to the shape shown in FIG. 10 when it extends distally beyond the distal end of sheath orlumen340.
• In the alternative embodiment of[0104]instrument350 shown in FIG. 10a,snare loop354 is mounted on the distal end of afiber optic bundle352′.Fiber optic bundle352′ may perform the functions described above forbundle320 or bundle330, thereby integrating those functions intoinstrument portion350.
• In the further alternative embodiment of[0105]instrument350 shown in FIG. 10b,snare loop354 is mounted on the distal end of atube352″, which can be used to deliver other types of instrumentation to the vicinity ofsnare loop354. For example,tube352″ may be metal (e.g., stainless steel) hypotube, and the other instrumentation delivered via that tube may be a tissue cutter for use in cooperation withsnare loop354 to perform a biopsy.
• In the still further alternative embodiment shown in FIG. 10[0106]c,snare loop354 is part of one continuous length ofwire352a.A possible advantage of the embodiment shown in FIG. 10cis that it permitssnare loop354 to be variable in size, determined by how much ofwire352ais extended from the distal end oflumen340.
• As shown in FIG. 11, the distal portion of steerable[0107]endoscopic snare300 is extended distally beyond the distal end ofcatheter210 and steered by the physician until it is adjacent to the exterior ofcoronary artery portion24.
• The next step in the illustrative procedure being described is preferably to deploy[0108]snare loop354 by extending it distally from the distal end ofstructure300 as shown in FIG. 12. Alternatively, this step could be performed somewhat later.
• The next step (also shown in FIG. 12) is to inflate[0109]balloon132 to pushtube120 against the opposite side wall ofcoronary artery20 atlocation24. Thenstylet wire150 is moved in the distal direction as shown in FIG. 12 so that itsdistal tip152 passes through the wall of the coronary artery. As was mentioned earlier, the distal end of the stylet wire lumen intube120 is shaped to help guidestylet wire150 through the coronary artery wall. Afterstylet wire150 is through the coronary artery wall,balloon132 can be deflated.Balloon132 may be a perfusion balloon which allows continued blood flow alongartery20 even while the balloon is inflated.
• It may not be necessary to have a[0110]balloon132 directly opposite the outlet forwire150. For example, FIG. 12ashows an alternative embodiment in which aperfusion balloon132′ is provided ontube120 proximally of the outlet forwire150.Balloon132′ is inflated when it is desired to stabilize the location oftube120 in coronary artery20 (e.g., while the distal portion ofwire150 is being pushed out through the coronary artery wall). Another possibility is for a balloon like132′ to be near the distal end of a balloon catheter from whichtube120 extends distally. Still another possibility may be to omit balloons like132 and132′ entirely. If aballoon132 or132′ is provided, it may not be necessary for it to be a perfusion balloon.
• When the distal portion of[0111]stylet wire150 is outsidecoronary artery20, the next step is to ensure that the distal portion of the wire passes throughsnare loop354 as shown in FIG. 12 or FIG. 12a.This may be facilitated by continued use of the visual observation and steering capabilities ofsnare300. An especially preferred technique is to deploysnare loop354 so that it is next tocoronary artery section24. Then whenstylet wire150 emerges from the coronary artery at24, it immediately passes throughsnare loop354 with no further manipulation being required.
• Once[0112]wire150 is throughsnare loop354, snare sheath orlumen340 is moved distally relative to the snare loop. This causessnare loop354 to close down onwire150. Snare sheath orlumen340 also tends to trap the distal portion ofwire150 and to fold that wire portion back on itself inside sheath orlumen340 as shown in FIG. 13.
• When the condition shown in FIG. 13 is achieved,[0113]longitudinal structures150 and350 are securely interengaged inside snare sheath orlumen340. The next step is to pullwire352 in the proximal direction all the way out of the patient at location202 (FIG. 5). Because of the interengagement betweenwires150 and352, withdrawingwire352 pulls as muchadditional wire150 into the patient from external location102 (FIG. 1). Whenwire352 has been completely removed from the patient, there is then onecontinuous wire150 from outside the patient at102, through the patient, to outside the patient at202.Wire150 can now be moved in either longitudinal direction through the patient. This wire or another wire could be used to help pull various apparatus into the patient via the tube or tubes through which the wire passes.
• After one[0114]continuous wire150 has been established through the patient as described above, steerableendoscopic snare300 may be withdrawn from the patient by pulling it proximally out ofcatheter210. The condition of the apparatus inside the patient is now as shown in FIG. 14. Note that the presence of fixed outlets for the wire from the distal portion oftube120 and the distal end ofcatheter210 preventswire150 from cuttingtissues20 and30 when the wire is pulled in either longitudinal direction. The portion ofwire150 extending through the interior of the patient betweenelements120 and210 may haveradiologic markers154 equally spaced along its length. These can be viewed radiologically by the physician to determine the distance betweenregions24 and34 viawire150. This helps the physician select the correct length of graft needed betweenregions24 and34.
• The next phase of the illustrative procedure being described is to install a new length of tubing between[0115]regions24 and34. The new length of tubing may be either an artificial graft, natural body organ tubing harvested from the patient's body, or a combination of artificial and natural tubing (e.g., natural tubing coaxially inside artificial tubing). In the following discussion it is assumed that the new tubing is to be natural tubing (e.g., a length of the patient's saphenous vein that has been harvested for this purpose) inside an artificial conduit. When such a combination of natural and artificial conduits is used, both conduits can be delivered and installed simultaneously, or the outer artificial conduit can be delivered and installed first, and then the inner natural conduit can be delivered and installed. The following discussion initially assumes that the latter technique is employed.
• In accordance with the above-stated assumptions, the next step in the procedure is to use[0116]catheter210 andwire150 to deliver an artificial conduit so that it extends betweenregions24 and34. The distal portion of anillustrative assembly400 for doing this is shown in FIG. 15. (Several alternative constructions of this portion of the apparatus are shown in later FIGS. and described below.)
• As shown in FIG. 15[0117]assembly400 includes a threaded, conical,distal tip412 mounted on a tubular member410 (e.g., metal hypotube) through whichwire150 can freely pass. Additional details regarding various possible constructions oftip412 are provided later with reference to FIGS. 15a-15g,but it should be mentioned here that in thisembodiment tip412 is selectively collapsible to facilitate its withdrawal from the patient after it has served its purpose. Anothertubular member420 is disposed concentrically aroundtubular member410. Aninflatable balloon422 is mounted on the distal end oftubular member420.Tubular member420 includes an axially extending lumen (not shown in FIG. 15) for use in selectively inflating and deflatingballoon422.Balloon422 is shown deflated in FIG. 15.
• Coaxially around[0118]tubular member420 is anartificial graft conduit430. An illustrative embodiment of asuitable conduit430 is shown in FIG. 16 and includes a tube formed of aframe432 of a first highly elastic material (such as nitinol) with a covering434 of a second highly elastic material (e.g., a rubber-like material such as silicone) substantially filling the apertures in the frame. Additional information regarding this possible embodiment ofconduit430 and other artificial graft structures in accordance with the invention is provided in later portions of this specification. Here it will suffice to say that this structure is extremely elastic, flexible, pliable, and resilient. For example, it can be stretched to a small fraction of its original diameter, and it thereafter returns by itself to its original size and shape without damage or permanent deformation of any kind. In addition, this structure is distensible so that it may pulsate very much like natural circulatory system tubing in response to pressure waves in the blood flow. This helps keep the conduit open, especially if it is used by itself as the final graft conduit. At its distal end, extensions offrame432 are flared out to form resilient hooks orbarbs436, the purpose of which will become apparent as the description proceeds. Near the proximal end ofconduit430 two axially spacedresilient flaps438aand438bwithbarbs439 are provided. The purpose and operation ofelements438 and439 will also become apparent as the description proceeds.
• In assembly[0119]400 (see again FIG. 15, and also FIG. 17),barbs436 and flaps438 are compressed radially inwardly and confined withinconduit delivery tube440, which coaxially surroundsconduit430. Indeed,conduit430 may be somewhat circumferentially compressed bytube440.
• The portion of[0120]assembly440 at which the proximal end ofconduit430 is located is shown in FIG. 17. There it will be seen how flaps438 are confined withinconduit delivery tube440. FIG. 17 also shows howtubes410,420, and440 extend proximally (to the right as viewed in FIG. 17) from the proximal end ofconduit430 so that the physician can remotely control the distal portion ofassembly400 from outside the patient.
• To install[0121]artificial graft conduit430 in the patient betweenregions24 and34,assembly400 is fed into the patient alongwire150 throughcatheter210. Whentip412 reachescoronary artery portion24,tip412 is threaded into and through the coronary artery wall by rotatingtube410 and therefore tip412. (Tube120 may be pulled back slightly at this time to make sure that it does not obstructtip412.) The passage oftip412 through the coronary artery wall opens up the aperture in that wall. Aftertip412 passes through the artery wall, that wall seals itself against the outside of the distal portion ofconduit delivery tube440 as shown in FIG. 18.
• The next step is to push[0122]tube410 andtip412 distally relative todelivery tube440, which is held stationary.Conduit430 is initially moved distally withcomponents410 and412. This may be done by inflatingballoon422 so that it engagesconduit430, and then movingtube420 distally withcomponents410 and412. Distal motion ofconduit430 movesbarbs436 beyond the distal end ofdelivery tube440, thereby allowing the barbs to spring out insidecoronary artery20 as shown in FIG. 19. This prevents the distal end ofconduit430 from being pulled proximally out of the coronary artery. Ifballoon422 was inflated during this phase of the procedure, it may be deflated before beginning the next phase.
• The next step is to pull[0123]delivery tube440 back slightly so that it is withdrawn fromcoronary artery20. Thentube420 is moved distally so thatballoon422 is radially inside the annulus ofbarbs436.Balloon442 is then inflated to ensure thatbarbs436 are firmly set incoronary artery20. Conditions are now as shown in FIG. 20. Cross sections ofballoon422 may be L-shaped when inflated (one leg of the L extending parallel to the longitudinal axis ofconduit430, and the other leg of the L extending radially outward from that longitudinal axis immediately distal of barbs436). This may further help to ensure thatbarbs436 fully engage the wall ofcoronary artery20.
• The next step is to deflate[0124]balloon422. Thendelivery tube440 is withdrawn proximally untilflap438a(but notflap438b) is distal of the distal end of the delivery tube. This allowsflap438ato spring radially out as shown in FIG. 21.Tube420 is then withdrawn untilballoon422 is just distal offlap438a.Then balloon422 is inflated, producing the condition shown in FIG. 21.
• The next steps are (1) to deflate[0125]distal balloon214, (2) to proximally withdraw catheter210 a short way, (3) to proximally withdrawtube420 to pressflap438aagainst the outer surface of the aorta wall, and (4) to proximally withdrawdelivery tube440 by the amount required to allowflap438bto spring out against the interior ofcatheter210, all as shown in FIG. 22. As a result of the above-described proximal withdrawal oftube420, thebarbs439 onflap438aare urged to enter the aorta wall tissue to help maintain engagement betweenflap438aand the wall of the aorta.Inflated balloon422 helps to setbarbs439 in the tissue whentube420 is tugged proximally.
• The next step is to insert the distal portion of[0126]delivery tube440 into the proximal end ofconduit430 as shown in FIG. 22a.The distal end ofconduit440 may be inserted all the way to the proximal end of balloon422 (see FIG. 23 for a depiction of this). A purpose of this step is to subsequently help control the rate at which blood is allowed to begin to flow throughconduit430.
• The next step is to proximally withdraw[0127]catheter210 by the amount required to releaseflap438bto spring out against the interior of the wall ofaorta30 as shown in FIG. 22b.Catheter210 may be subsequently pushed back againstflap438bas shown in FIG. 23 to help securely engage that flap against the aorta wall.
• [0128]Artificial graft conduit430 is now fully established betweenaorta region34 andcoronary artery region24. The next steps are therefore to deflateballoon422 and proximally withdrawtube420, to collapsetip412 and proximally withdrawtube410, and to proximally withdrawdelivery tube440. The proximal end ofconduit430 is now as shown in FIG. 24. As possible alternatives to what is shown in FIG. 24, the distal end ofcatheter210 could be left pressed up againstproximal flap438band/or the distal portion ofdelivery tube440 could be left inside the proximal portion ofconduit430. If the latter possibility is employed, then delivery of the natural graft conduit (described below) can be throughtube440.
• Several illustrative embodiments of[0129]collapsible tips412 are shown in FIGS. 15a-15g.In the first embodiment (shown in FIGS. 15a-15c) a frame of wire struts412aextends radially out and proximally back from the distal end of hypotube410 (see especially FIG. 15a). This frame is covered with a somewhat elastic polymer cover412b(FIG. 15b) which is provided with threads as indicated at412c.For example,threads412cmay be made of one or more spirals of nitinol wire or other metal. When it is desired to collapsetip412, another hypotube410a(which is disposed around hypotube410) is shifted distally relative to hypotube410 to invert andcollapse tip412 as shown in FIG. 15c.
• In the alternative embodiment shown in FIGS. 15[0130]dand15e,tip412 has a centralmain portion412eattached tohypotube410. Around the proximal portion ofmain portion412eare a plurality of triangular shapedportions412f,each of which is connected tomain portion412eby ahinge412g.The outer surface of the tip is threaded as indicated at412h.For example, in thisembodiment tip412 may be made of a plastic polymer material, and hinges412gmay be so-called “living” hinges between the various masses of the polymer. As soon astriangular portions412fmeet any resistance astip412 is withdrawn proximally, they pivot about theirhinges412gto the positions shown in FIG. 15e,thereby greatly reducing the circumferential size of the tip.
• In the further alternative embodiment shown in FIGS. 15[0131]fand15g,metal struts412jare attached to the distal end ofhypotube410 so that they extend radially out and proximally back. Although not shown in FIGS. 15fand15g,struts412jare covered with a cover and threads like the cover412bandthreads412cshown in FIG. 15band described above. Awire412kconnects a proximal portion of eachstrut412j,through an aperture inhypotube410, to the distal end of anotherhypotube410bwhich is disposed insidehypotube410. Whenwires412kare relaxed as shown in FIG. 15f,struts412jextend radially out beyond the circumference ofdelivery tube440. When it is desired to collapsetip412, hypotube410bis pulled back proximally relative to hypotube410 as shown in FIG. 15g.This causeswires412kto pullstruts412jin so that the outer circumference oftip412 is much smaller than the circumference ofdelivery tube440.
• Again, it should be mentioned that the use of a threaded,[0132]collapsible tip412 as described above is only one of several possibilities. Other alternatives are discussed below after completion of the discussion of the illustrative procedure which is being described and which will now be further considered with reference to FIG. 25 and subsequent FIGS.
• As has been mentioned, the illustrative procedure being described assumes that natural body conduit (e.g. a length of the patient's saphenous vein that has been harvested for this purpose) is installed inside[0133]artificial conduit430 after installation of the latter conduit. Anillustrative assembly500 for delivering a length of natural body conduit to installedconduit430 is shown in FIG. 25.
• As shown in FIG. 25,[0134]assembly500 includes atube510 disposed aroundwire150 so thattube510 is freely movable in either direction alongwire150.Tube510 has an inflatableannular balloon512anear its distal end and another inflatableannular balloon512bspaced in the proximal direction fromballoon512a.Tube510 includes separate inflation lumens (not shown) for each of balloons512 so that the balloons can be separately inflated and deflated. An annular collar structure or ring520ais disposed concentrically aroundballoon512a,and a similar annular collar structure orring520bis disposed concentrically aroundballoon512b.Balloons512 may be partly inflated. Each of rings520 may have radially outwardly extendingbarbs522. A length of natural body conduit530 (e.g., saphenous vein as mentioned earlier) extends fromring520ato ring520baround the intervening portion oftube510.Barbs522 may extend through the portions ofconduit530 that axially overlap rings520. Adelivery tube540 is disposed aroundconduit530. In use,tubes510 and540 extend proximally (to the right as viewed in FIG. 25) out of the patient to permit the physician to remotely control the distal portion ofassembly500.
• Although not shown in FIG. 25,[0135]assembly500 may include a spring coil (similar tocoil450 in FIG. 36) extending between rings520 inside ofconduit530 to help holdconduit530 open and out againstdelivery tube540 or subsequently out againstconduit430. Instead of balloons512 being both in thesame tube510,balloon512amay be on a relatively small first tube, whileballoon512bis on a larger second tube that concentrically surrounds the proximal portion of the first tube. The first and second tubes are axially movable relative to one another, thereby allowing the distance between balloons512 to be adjusted forgrafts530 of different lengths.
• [0136]Assembly500 is employed by placing it onwire150 leading intocatheter210.Assembly500 is then advanced distally alongwire150 throughcatheter210 and then intoconduit430 until the distal end ofconduit530 is adjacent the distal end ofconduit430 and the proximal end ofconduit530 is adjacent the proximal end ofconduit430. The condition of the apparatus at the distal end ofassembly500 is now as shown in FIG. 26. The condition of the apparatus at the proximal end ofconduit530 is as shown in FIG. 28.
• The next step is to proximally withdraw[0137]delivery tube540 so that the distal portion ofconduit530 and distalbarbed ring520aare no longer inside the distal portion ofdelivery tube540. Thendistal balloon512ais inflated to circumferentially expandring520aand to setbarbs522 throughconduit530 into the surrounding portion ofconduit430 and coronaryartery wall portion24. This provides a completed anastomosis of the distal end ofconduit530 tocoronary artery20. FIG. 27 shows the condition of the apparatus at this stage in the procedure.
• The next step is to continue to proximally withdraw[0138]delivery tube540 until the proximal end ofconduit530 andproximal ring520bare no longer inside tube540 (see FIG. 29). Thenproximal balloon512bis inflated to circumferentially expandring520band thereby setbarbs522 throughconduit530 into the surrounding portion ofconduit430 and aorta wall portion34 (see FIG. 30). This provides a completed anastomosis of the proximal end ofconduit530 toaorta30.
• The next step is to deflate[0139]balloons512aand512band proximally withdrawtube510 anddelivery tube540 from the patient viacatheter210. Then wire150 is withdrawn from the patient, either by pulling it proximally fromcatheter210 or by pulling it proximally fromelements110 and120. Lastly,elements110,120, and210 are all proximally withdrawn from the patient to conclude the procedure. The bypass that is left in the patient is as shown in FIG. 31. This bypass extends fromaorta30 atlocation34 tocoronary artery20 atlocation24. The bypass includesnatural body conduit530 insideartificial graft conduit430. One end of the bypass is anchored and anastomosed tocoronary artery20 bybarbs436 and ring520a.The other end of the bypass is anchored and anastomosed to aorta30 by flaps438 andring520b.
• The particular uses of the invention that have been described in detail above are only illustrative of many possible uses of the invention. Other examples include same-vessel bypasses in the coronary area and vessel-to-vessel and same-vessel bypasses in other portions of the circulatory system (including neurological areas, renal areas, urological areas, gynecological areas, and peripheral areas generally). A same-vessel bypass is a bypass that extends from one portion of a vessel to another axially spaced portion of the same vessel. In FIG. 32, bypass[0140]620 is a same-vessel bypass around a narrowing612 invessel610. For ease of comparison to previously described embodiments, the various components ofbypass620 are identified using the same reference numbers that are used for similar elements in FIG. 31. The invention is also applicable to procedures similar to any of those mentioned above, but for non-circulatory systems such as urological tubing.
• It has been mentioned that the collapsible tip structures shown, for example, in FIGS.[0141]15-15gare illustrative of only one of several possible approaches to providing a structure that can penetrate the wall ofcoronary artery20 from outside the artery. Another example of a suitable structure is shown in FIG. 33. To facilitate comparison to FIG. 15, FIG. 33 uses reference numbers with primes for elements that are generally similar to elements identified by the corresponding unprimed reference numbers in FIG. 15.
• In the embodiment shown in FIG. 33[0142]distal tip412′ hasexternal threads414 for helping to grip and dilate tissue such as the wall ofcoronary artery20 astip412′ is rotated aboutwire150 by rotation of proximally extendingtubular shaft410′.Threads414 continue asthreads442 on the exterior of the distal portion oftube440′.Threads414 also threadedly engage withthreads444 on the interior of the distal portion oftube440′. Thus when both ofstructures410′ and440′ are rotated together,threads414 and442 tend to pulltip412′ and then the distal portion oftube440′ into and through the wall ofcoronary artery20. In the course of this,threads412′ transfer the tissue tothreads442. Thereafter,structure410′ can be removed fromstructure440′ by rotatingstructure410′ in the direction relative to structure440′ that causesthreads414 and444 to cooperate to shifttip412′ proximally relative to structure440′. Whentip412′ has thus shifted proximally beyondthreads444,elements410′ and412′ can be pulled proximally out of the patient.Tube440′, which remains in place through the coronary artery wall, can thereafter be used as a guide tube for delivery of a graft structure (such as430 (FIGS.15-17)) and associated instrumentation (such as structure420 (e.g., FIGS. 15 and 17)) to the operative site.
• Another illustrative alternative embodiment of some of the instrumentation shown in FIG. 15 is shown in FIGS. 34 and 35. Once again, to facilitate comparison to FIG. 15, FIGS. 34 and 35 use reference numbers with primes for elements that are generally similar to elements identified by the corresponding unprimed reference numbers in FIG. 15. In the embodiment shown in FIGS. 34 and 35[0143]barbs436′ are connected to the distal end of aserpentine ring439 which is connected in turn to the distal end offrame432′.Barbs436′ are initially held in the form of a distally pointed cone byyieldable bands437a,437b,437c,and437d.As elsewhere alonggraft conduit430′, the spaces betweenbarbs436′ are substantially filled by a highly elastic material such as silicone rubber. Bands437 may be made of a polymeric or other suitable yieldable material. Alternatively, bands437 could be serpentine metal members that yield by becoming straighter. Bands437 are initially strong enough to preventbarbs436′ from flaring radially outward fromconduit430′ as the barbs are resiliently biased to do. However, bands437 can be made to yield by inflatingballoon422′ (on the distal end oftube420′) inside the annulus ofbarbs436′.
• [0144]Barbs436′ can be forced through tissue such as the wall ofcoronary artery20 in their initial cone shape. Sufficient pushing force can be applied to the cone ofbarbs436′ in any of several ways. For example,tube420′ may be metal (e.g., stainless steel) hypotube which can transmit pushing force to the cone ofbarbs436′ by inflatingballoon422′ to trap the base of the cone betweenballoon422′ andtube440. Additional pushing force may then also be applied viatube440 itself.
• When a sufficient portion of the height of the cone of[0145]barbs436′ is through the coronary artery wall,balloon422′ is inflated inside the cone as shown in FIG. 35 to cause bands437 to yield. This allowsbarbs436′ to flare radially outward inside the coronary artery, thereby anchoring the distal end ofconduit430′ to the artery. Bands437 may be made progressively weaker in the distal direction to facilitate prompt yielding of distal bands such as437aand437bin response to relatively little inflation ofballoon422′, whereas more proximal bands such as437cand437ddo not yield until somewhat later in response to greater inflation ofballoon422′. This progression of yielding may help ensure that the annulus of barbs flares out in the desired trumpet-bell shape inside the coronary artery.
• FIGS. 36 and 37 illustrate another possible use of a cone structure like that shown in FIGS. 34 and 35, as well as illustrating other possible aspects of the invention. These FIGS. illustrate a structure that can be used to deliver an artificial graft conduit, or a natural graft conduit, or both an artificial graft conduit and a natural graft conduit simultaneously (e.g., with the natural conduit coaxially inside the artificial conduit). In the particular case shown in FIGS. 36 and 37 it is assumed that only natural graft conduit is being delivered, but it will be readily apparent that artificial graft conduit could be substituted for or added outside the natural graft conduit.[0146]
• In the embodiment shown in FIGS. 36 and 37 the cone of[0147]barbs436′ is mounted on the distal end of a highlyelastic coil spring450. The proximal end ofcoil450 is attached to ring460. The cone ofbarbs436′ is provided with additional, relatively short, radially outwardly projectingbarbs436″ near the proximal base of the cone. As shown in FIG. 37,barbs436″ extend into and/or through the distal portion of a length ofgraft tubing530, which (as has been mentioned) is assumed in this case to be natural body organ tubing such as saphenous vein.Ring460 is similarly provided with radially outwardly extendingbarbs462 which extend into and/or through the proximal portion ofgraft conduit530.Ring460 also includes resilient radially outwardly extendingannular flaps438aand438bwithbarbs439, all similar to correspondingly numbered elements in FIG. 16.Spring450, which is insideconduit530 between the cone ofbarbs436′ andring460, helps to support and hold open the graft conduit.Structure420′ (similar to structure420′ in FIGS. 34 and 35 and includingballoon422′ as shown in those FIGS.) is disposed aroundwire150 insidestructures436′,450,460, and530.Delivery tube440 is disposed aroundconduit530.
• The embodiment shown in FIGS. 36 and 37 illustrates a structure which can be used to deliver and install natural body organ conduit without any full length artificial graft conduit being used. In a manner similar to what is shown in FIGS. 34 and 35, the structure shown in FIG. 37 is delivered to the operative site via[0148]wire150. The cone ofbarbs436′ is forced through the wall ofcoronary artery20 and then flared radially outward inside the coronary artery to anchor the distal end of the graft conduit to that artery. The distal end ofdelivery tube440 is pulled back as needed to aid in attachment of the distal end of the graft structure. Attachment of the proximal end of the graft structure to the wall ofaorta30 is performed similarly to what is shown in FIGS.21-24. Accordingly, withdistal flap438ajust outside the wall ofaorta30,delivery tube440 is pulled back proximally to expose that flap.Flap438ais thereby released to spring out and engage the outer surface of the aorta wall. After that has occurred,proximal flap438bis adjacent the inner surface of the aorta wall.Tube440 is pulled back proximally even farther to exposeflap438bso that it can spring out and engage the inner surface of the aorta wall. Naturalbody organ graft530 is now fully installed in the patient.Structures436′,450, and460 remain in place in the patient to help anchor the ends ofgraft conduit530 and to help hold open the medial portion of that conduit.
• In embodiments like FIGS,[0149]36 and37,coil450 is optional. Ifcoil450 is used, its ends may or may not be attached tostructures436 and/or460.
• A coil like[0150]coil450 can be used in other embodiments of the invention. For example, a coil like450 could be used betweenrings520aand520bin embodiments like that shown in FIG. 25 to help holdopen graft conduit530 in that embodiment.
• Still another illustrative alternative embodiment of some of the instrumentation shown in FIG. 15 is shown in FIG. 38. To facilitate comparison to FIG. 15, FIG. 38 uses reference numbers with double primes for elements that are generally similar to elements identified by the corresponding unprimed reference numbers in FIG. 15. In the embodiment shown in FIG. 38, the distal end of[0151]artificial graft conduit430″ is attached toexpandable ring430a.Elongated barbs436″ extend distally from the distal end ofring430a.The distal ends ofbarbs436″ are turned back in the proximal direction and extend just far enough into the distal end oftube420″ to be releasably retained by that tube.Barbs436″ are resiliently biased to extend radially outward fromring430a,but are initially restrained from doing so by the presence of their distal end portions in the distal end oftube420″. Thusbarbs436″ initially form a distally pointing cone that can be pushed through tissue such as the wall ofcoronary artery20 in the same manner that has been described above in connection with FIGS.34-37.Structure420″, which may be metal (e.g., stainless steel) hypotube with an inflatableannular balloon422″ near its distal end, may be used to help push the cone through the tissue.
• After the distal portion of the cone of[0152]barbs436″ has been pushed through the wall ofcoronary artery20,tube420″ is shifted proximally relative to the barbs to release the distal end portions of the barbs. This allowsbarbs436″ to spring radially outward fromring430ainsidecoronary artery20, thereby anchoring the distal end of the graft conduit in the coronary artery.Ring430acan then be circumferentially expanded to increase the size of the connection betweencoronary artery20 and the distal portion of the graft conduit. If desired, each ofbarbs436″ may be twisted180° as shown in FIG. 39 before it enters the distal end oftube420″. This promotes turning of the extreme distal end portions of the barbs toward the coronary artery wall when the barbs are released fromtube420″.
• [0153]Ring430aandbarbs436″ may be made of any suitable material such as any 300-series stainless steel (e.g., 316L stainless steel). Another material that may be suitable forbarbs436″ is nitinol. As in previously described embodiments, theelastic cover434 that forms part ofconduit430″ preferably extends toregions430aand436″.
• A preferred artificial graft (such as[0154]conduit430 in FIG. 16) in accordance with this invention includes an open frame structure (such as432 in FIG. 16). This frame structure may have any desired shape such as a tube, a flat or contoured sheet, etc. The frame structure may be formed in any suitable way such as by cutting apertures in an initially imperforate structure; forming a mesh of strands of frame material; braiding, knitting, weaving, or felting together strands of frame material; etc. The frame material is preferably an elastic material. Preferred materials are metal, although polymeric materials may also be used. The presently most preferred material is nitinol, and the presently most preferred structure for the frame of a tubular graft is a braid of nitinol wires.
• The above-described graft frame is preferably covered with a covering of elastic rubber-like material which substantially fills the apertures in the frame as at[0155]434 in FIG. 16. The covering may be inside the frame structure, outside the frame structure, or both inside and outside the frame structure. Preferred rubber-like materials for the covering are polymeric materials, especially polymeric rubber materials. The presently most preferred rubber-like material is silicone. Examples of other suitable rubber-like materials are stretchable urethane, stretchable PTFE, natural rubber, and the like. For some applications it may be desirable to make the covering porous. Other applications may not benefit from such porosity. Thus the covering can be made either porous or non-porous as desired.
• The graft structure may include one or more coatings over the above-described covering. In the case of a tubular graft the coating(s) may be inside the tube, outside the tube, or both inside and outside the tube. Possible coating materials include bio-compatible materials and/or drugs. Examples include hydrophylic polymers such as hydrophylic polyurethane (to create a lubricious surface), parylene (a polymer commonly used to coat pacemakers), PTFE (which may be deposited from a PTFE vapor using a process that is sometimes called vapor transport), the drug Heparin (a common anti-coagulant), collagen, human cell seeding, etc. One purpose of such a coating may be to give the coated surface a very high degree of bio-compatibility and/or a very high degree of smoothness.[0156]
• The graft structure may or not include hooks, barbs, flaps, or other similar structures for such purposes as helping to anchor the graft in the body, provide anastomoses between the graft and existing body tubing, etc. Several examples of such structures are shown and described elsewhere in this specification. If provided, such hooks, barbs, flaps, and the like may be extensions of the frame structure or may be molded with or otherwise added to the frame or covering.[0157]
• The most preferred grafts of this invention (e.g., those with a nitinol frame and silicone covering) are highly elastic. The elastic nature of these graft structures allows them to be deployed less invasively (e.g., intravascularly or at least percutaneously). This avoids or reduces the need for surgical implantation. For example, a tubular graft of this construction can be stretched to several times its relaxed length, which greatly reduces its diameter. This facilitates intravascular delivery of the graft. When released from the delivery apparatus, the graft automatically returns to its relaxed length and diameter, with no ill-effects of any kind from its previous deformation. If installed in the circulatory system, the graft is so flexible and elastic that it pulsates in response to pressure waves or pulses in the blood flow. This distensibility of the graft may help prevent blood clots. Coatings that are used on the graft are preferably similarly distensible.[0158]
• In the grafts of this invention that are made with a braided nitinol wire frame and a silicone covering, the preferred wire diameter is in the range from about 0.0005 to about 0.01 inches. An especially preferred wire diameter is about 0.002 inches. The preferred silicone covering thickness is in the range from about 0.00025 to about 0.1 inches. Two covering layers may be used: one inside and one outside the frame structure. If the covering is made porous, the preferred pore size is in the range from about 1 to about 500 microns. An especially preferred pore size is about 30 microns. The preferred covering porosity is in the range from about 50% to about 95%. In other words, from about 50% to about 95% of the volume of the covering is pore space. If any coatings are applied to the graft, they are preferably thinner than the covering.[0159]
• For the preferred grafts of this invention, a preferred manufacturing process in accordance with the invention includes placing or forming the frame structure of the graft on a form (e.g., a rod-like mandrel or tube in the case of the frame for a tubular graft). The form (e.g., mandrel) may be coated with a release agent such as polyvinyl alcohol. The covering is then applied to the frame or the form. The covering is cured, and the frame and covering are removed from the form. Any release agent that remains on the graft is removed. For example, if the release agent is polyvinyl alcohol, it may be removed by boiling the graft in water. If a covering is desired on the inside of the graft, a layer of the covering material may be applied to the form before the frame structure is placed or formed on the form. The form may be provided with a very smooth surface to give the finished graft a correspondingly smooth surface. For example, a very smooth mandrel may be used to give the inside of a tubular graft a very smooth surface.[0160]
• If one or more coatings are desired on the graft, the coating may be done at any suitable time. For example, the coating may be done after the graft has been removed from the form. The coating or coatings may be applied using any suitable technique such as dipping, electrostatic spraying, vapor transport, in vitro cell reproduction, etc.[0161]
• A preferred method in accordance with the invention for making the graft covering porous is to mix particles of another material with the covering material before applying the covering material to the frame. The particulate material is selected as one which is stable or at least relatively stable during curing of the covering on the frame, but which can then be removed from the cured covering to leave the covering with the desired porosity. For example, the particulate material may be a salt such as ammonium carbonate, which is relatively stable at temperatures substantially below about 78° C., but which vaporizes relatively rapidly at an elevated temperature (i.e., about 78° C.) that is not harmful to the cured coating material. Any other particulate material that can be removed by vaporization or solution can be used. For example, the particulate material may be removed by dissolving in water or another solvent, by exposure to air or another vaporization medium, by heat, by vacuum, or by any other suitable means.[0162]
• Porosity of the covering is believed to be beneficial for circulatory system grafts. It may promote growth of a cell structure on the inside wall of the graft. And in all uses, porosity may promote better adherence of the above-mentioned coatings to the graft.[0163]
• It will be understood that the foregoing is only illustrative of the principles of the invention, and that various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. For example, the order of some steps in the procedures that have been described are not critical and can be changed if desired. The manner in which radiologic elements and techniques are used for observation of the apparatus inside the patient may vary. For example, radiologic fluids may be injected into the patient through various lumens in the apparatus to help monitor the location of various apparatus components in the patient, and/or radiologic markers (of which the above-described markers such as[0164]112,124, and154 are examples) may be provided anywhere on the apparatus that may be helpful to the physician.

Claims (27)

The invention claimed is:

1. An instrument for creating an aperture through a side wall of a patient's tubular body organ structure at a point along that structure which is remote from the location at which the instrument is inserted into said tubular structure and from which the instrument is controlled comprising:

an elongated guide structure longitudinally insertable into said tubular structure at said location and extendable along the interior of said tubular structure to said point; and

a longitudinal structure substantially aligned with and guided by said guide structure and longitudinally movable relative thereto, a distal portion of said longitudinal structure being adapted to penetrate said side wall when forced against said side wall by a sufficient amount of distal motion of said longitudinal structure relative to said guide structure.

2. The apparatus defined inclaim 1 wherein said guide structure includes an expandable structure for stabilizing said guide structure in said tubular structure.

3. The apparatus defined inclaim 2 wherein said expandable structure comprises an inflatable balloon.

4. The apparatus defined inclaim 3 wherein said balloon is a perfusion balloon.

5. The apparatus defined inclaim 1 wherein said guide structure has a distal portion adapted to deflect said distal portion of said longitudinal structure laterally toward said side wall.

6. The apparatus defined inclaim 1 wherein said guide structure has a distal portion which includes a laterally expandable structure for urging said distal portion of said guide structure into contact with said side wall.

7. The apparatus defined inclaim 6 wherein said laterally expandable structure comprises an inflatable balloon.

8. The apparatus defined inclaim 7 wherein said balloon is a perfusion balloon.

9. The apparatus defined inclaim 6 wherein said laterally expandable structure is disposed on a first lateral side of said distal portion of said guide structure, and wherein said distal portion of said guide structure is adapted to deflect said distal portion of said longitudinal structure laterally toward a second lateral side of said disal portion which faces away from said first lateral side.

10. The apparatus defined inclaim 1 wherein said guide structure comprises:

a radiologic marker on a distal portion of said guide structure.

11. The apparatus defined inclaim 1 wherein said guide structure comprises a tube through which said longitudinal structure extends longitudinally.

12. The apparatus defined inclaim 1 further comprising:

a tube longitudinally insertable into said tubular structure at said location and extendable along the interior of said tubular structure to an intermediate location which is between said location and said point, said guide structure being longitudinally insertable through said tube.

13. The apparatus defined inclaim 1 wherein said distal portion of said longitudinal structure, is sharpened to facilitate penetration of said side wall.

14. The apparatus defined inclaim 1 wherein said distal portion of said longitudinal structure is externally threaded to facilitate penetration of said side wall when said distal portion of said longitudinal structure is rotated about its longitudinal axis.

15. The apparatus defined inclaim 1 wherein said distal portion of said longitudinal structure is resiliently biased to deflect laterally toward said side wall when released from guidance by said guide structure.

16. The apparatus defined inclaim 1 wherein said distal portion of said longitudinal structure comprises:

a substantially central longitudinal member having a distal portion which is adapted to make an initial penetration of said side wall; and

a tubular member disposed substantially concentrically about said central member and longitudinally movable relative thereto for circumferentially enlarging said initial penetration when forced through said side wall after said central longitudinal member has made said initial penetration.

17. The apparatus defined inclaim 16 wherein said tubular member is externally threaded to facilitate passage of said tubular member through said side wall when said tubular member is rotated about its longitudinal axis.

18. The apparatus defined inclaim 1 wherein said distal portion of said longitudinal structure comprises:

a tubular member insertable through said aperture, said tubular member having a selectively enlargeable structure disposed on its exterior at a predetermined distance proximally from its distal end for selectively preventing more than the portion of said tubular member which is distal of said enlargeable structure form passing out of said tubular structure via said aperture.

19. The apparatus defined inclaim 18 wherein said enlargeable structure comprises an inflatable balloon.

20. The apparatus defined inclaim 19 wherein said balloon extends annularly around the exterior of said tubular member and projects radially outwardly from said tubular member in all radially outward directions when inflated.

21. The apparatus defined inclaim 1 wherein said distal portion of said longitudinal structure comprises:

a tubular member insertable through said aperture, said tubular member having a selectively enlargeable structure disposed on its exterior at a predetermined distance proximally from its distal end for selectively preventing the portion of said tubular member which is distal of said enlargeable structure from moving proximally back though said aperture.

22. The apparatus defined inclaim 21 wherein said enlargeable structure comprises an inflatable balloon.

23. The apparatus defined inclaim 22 wherein said balloon extends annularly around the exterior of said tubular member and projects radially outwardly from said tubular member in all radially outward directions when inflated.

24. The apparatus defined inclaim 1 wherein said distal portion of said longitudinal structure comprises:

a tubular member insertable through said aperture, said tubular member having first and second selectively inflatable balloons disposed on the exterior thereof, said balloons being spaced from one another along the longitudinal axis of said tubular member, and each of said balloons extending annularly around said tubular member so that each of said balloons forms an enlarged ring around the outside of said tubular member when inflated, the spacing between said balloons being such that said first and second balloons can be located adjacent respective interior and exterior surfaces of said side wall when said tubular member is inserted through said apertures.

25. The apparatus defined inclaim 24 wherein said spacing between said balloons is further such that said balloons resiliently compress said side wall between them when inflated.

26. The apparatus defined inclaim 24 wherein said balloons substantially prevent longitudinal motion of said tubular member through said aperture when inflated.

27. The apparatus defined inclaim 24 wherein said balloons help to prevent fluid leakage through said aperture around said tubular member when inflated.

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