Source: https://patents.google.com/patent/AU733020B2/en
Timestamp: 2019-05-19 15:40:59
Document Index: 433095364

Matched Legal Cases: ['art 14', 'art 14', 'art 14', 'art 14', 'art 14', 'art 14', 'art 14', 'art.\n3']

AU733020B2 - Methods and devices for improving blood flow to a heart of a patient - Google Patents
AU733020B2
AU733020B2 AU50804/98A AU5080498A AU733020B2 AU 733020 B2 AU733020 B2 AU 733020B2 AU 50804/98 A AU50804/98 A AU 50804/98A AU 5080498 A AU5080498 A AU 5080498A AU 733020 B2 AU733020 B2 AU 733020B2
AU50804/98A
AU5080498A (en
1996-10-17 Priority to US733128 priority
1996-12-20 Priority to US770319 priority
1997-10-16 Application filed by Ethicon Endo Surgery Inc filed Critical Ethicon Endo Surgery Inc
1997-10-16 Priority to PCT/US1997/018652 priority patent/WO1998016154A1/en
1998-05-11 Publication of AU5080498A publication Critical patent/AU5080498A/en
2001-05-03 Publication of AU733020B2 publication Critical patent/AU733020B2/en
1 METHODS AND DEVICES FOR IMPROVING BLOOD FLOW TO A HEART OF A PATIENT RELATED APPLICATIONS This application is a continuation-in-part of application Ser. No. 08/733128, filed on Oct. 17, 1996 now abandoned.
BACKGROUND OF THE INVENTION 10 Heart disease presents a major concern in western societies.
Heart disease may cause chest pains, strokes, heart attacks, or even death.
One form of heart disease is ischemic heart disease, a. condition where the heart or myocardium does not receive an adequate nutritive blood supply.
Typically, this condition occurs when the coronary arteries become blocked by plaque build-up on their inner walls.
**When the plaque build-up of the coronary arteries hinders the flow of blood to the heart, the heart may become starved for nutrition and oxygen. As a result, the tissue of the heart may scar, causing the heart to be weakened.
20 A number of approaches have been developed for treating heart disease. In less severe cases, proper diet and exercise may improve heart conditions. However, if diet and exercise are not effective, medication may be prescribed. If heart disease still persists, a minimally invasive or invasive procedure is usually performed.
RA, Coronary bypass surgery involves open heart surgery where a surgeon removes a blood vessel from another part of the body, such as the S leg or inside the chest wall, and uses the vessel to construct a detour around the blocked coronary artery. One end of the vessel is attached below the WO 98/16154 PCTIUS97/18652 -2blockage while the other end is attached above the blockage. As a result, blood may flow around the obstruction into the heart.
More recently, Laser Transmyocardial Revascularization (LTR) has been used as an alterative to coronary bypass surgery or PTCA.
This technique is used to supplement the blood supply received by the heart by providing the myocardium direct access to blood in the ventricle chamber. In one known approach, LTR is performed using a high power, pulsed, CO 2 laser. The laser may be operated to create a channel from the ventricle to the myocardium. The laser is fired against the outer ventricle surface of the heart when the ventricle is full of blood. The blood in the ventricle acts as a backstop preventing the energy of the laser from penetrating through the other side of the ventricle or damaging nearby tissue.
WO 98/16154 PCT/US97/18652 -3- After a channel is formed, blood may flow through the resulting channel from the ventricle into the myocardium.
Ultrasonic devices are also known for assisting a surgeon in cutting tissue. For example, U.S. Patent No. 5,449,370 entitled "Blunt Tipped Ultrasonic Trocars," which is herein incorporated by reference, discloses a trocar to puncture an abdominal wall of a patient. U.S. Patent No. 5,324,299 entitled "Ultrasonic Scalpel Blade And Method Of Application," which is incorporated herein by reference, discloses an ultrasonic device including a blade portion having a recess that defines a hook for grasping and tensioning loose tissue to facilitate cutting. U.S.
Patent No. 5,322,055 entitled "Clamp Coagulator/Cutting System For Ultrasonic Surgical Instruments," which is incorporated herein by reference, also discloses a surgical instrument for cutting tissue. The instrument includes an ultrasonic blade for use with a clamp to improve tissue cutting.
SUMMARY OF THE INVENTION The present invention provides methods and devices to treat certain types of heart disease and to improve blood flow to tissue in a heart of a patient. The devices and methods of the present invention provide an efficient and minimally intrusive procedure to improve the blood supply to WO 98/16154 PCT/US97/18652 -4the myocardium of the heart. This is accomplished by a form of transmyocardial revascularization (TMR) where the heart is ultrasonically pierced to create a channel from the left ventricle to the myocardium.
The invention, together with further.objects and attendant advantages, will best be understood by reference to the following detailed description of the presently preferred embodiment of the invention, taken in conjunction with the accompanying drawings.
WO 98/16154 PCTIUS97/18652 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial diagrammatic view of one preferred embodiment of a probe assembly of an surgical system creating channels in a heart of a patient; FIG. 2 is a partially broken away view and in partial crosssection of a preferred embodiment of an surgical system made in accordance with the present invention; FIGS. 3-9 are fragmentary perspective views of preferred embodiments of an end effector of the surgical system of FIG. 2; FIGS. 10-11 are fragmentary perspective views of other preferred embodiments of an end effector of an surgical system of FIG. 2; FIG. 12 is a perspective view of another preferred embodiment of an surgical system according to the present invention; and FIG. 13 is a view partially broken away, cross-sectional view of the acoustic assembly of the surgical system of FIG. 12.
Referring now to the drawings in detail, and particularly to FIG. 1, a preferred embodiment of an end effector, as further described below, extending from a catheter 70 of a surgical system 10 is shown forming holes or channels 12 (shown in phantom) in a heart 14 of a WO 98/16154 PCTIUS97/18652 -6patient. The catheter 70 of the surgical system 10 is routed through the vascular system of the patient to a position near the inner ventricle wall 16 of the heart 14. The catheter 70 may be inserted into a femoral artery and guided through the aorta into the left ventricle of the heart, or the catheter 70 may be inserted into the femoral vein and advanced to the right side of the heart where the catheter 70 enters the left ventricle transeptically. The catheter 70 may include fiber optics (not shown) to allow a user or surgeon to view and monitor the procedure.
Alternatively, the catheter 70 may be viewed by ultrasound imaging or fluoroscopic imaging.
Referring now to FIG. 2, a preferred embodiment of the surgical system 10 is illustrated. The surgical system 10 generally includes a generator 30, a handpiece assembly 50, and an acoustic or transmission assembly 80. The generator 30 sends an electrical signal through a cable 32 at a selected amplitude, frequency, and phase determined by a control system of the generator 30. As will be further described, the signal causes one or more piezoelectric elements of the acoustic assembly 80 to expand and contract, thereby converting the electrical energy into mechanical motion. The mechanical motion results in longitudinal waves of ultrasonic energy that propagate through the acoustic assembly 80 in an acoustic standing wave to vibrate the acoustic WO 98/16154 PCT/US97/18652 -7assembly 80 at a selected frequency and amplitude. The end effector at the distal end of the acoustic assembly 80 is placed in contact with tissue of the patient to transfer the ultrasonic energy to the tissue. The cells of tissue in contact with the end effector of the acoustic assembly 80 will move with the end effector and vibrate.
As the end effector couples with the tissue, thermal energy or heat is generated as a result of internal cellular friction with the tissue.
The heat is sufficient to break protein hydrogen bonds, causing the highly structured protein collagen and muscle protein) to denature become less organized). As the proteins are denatured, a sticky coagulum forms to seal or coagulate small blood vessels when the coagulum is below 100°C. Deep coagulation of larger blood vessels results when the effect is prolonged.
As illustrated in FIG. 2, the generator 30 includes a control system integral to the generator 30, a power switch 34, and a triggering mechanism 36. The power switch 34 controls the electrical power to the generator 30, and when activated by the triggering mechanism 36, the generator 30 provides energy to drive the acoustic assembly 80 of the surgical system 10 at a predetermined frequency and to drive the end effector at a predetermined vibrational amplitude level. The generator may drive or excite the acoustic assembly 80 at any suitable resonant frequency of the acoustic assembly WO 98/16154 PCT/US97/18652 -8- When the generator 30 is activated via the triggering mechanism 36, electrical energy is continuously applied by the generator to a transducer assembly 82 of the acoustic assembly 80. A phase lock loop in the control system of the generator 30 monitors feedback from the acoustic assembly 80. The phase lock loop adjusts the frequency of the electrical energy sent by the generator 30 to match a preselected harmonic frequency of the acoustic assembly 80. In addition, a second feedback loop in the control system maintains the electric current supplied to the acoustic assembly 80 at a preselected constant level in order to achieve substantially constant vibrational amplitude at the end effector of the acoustic assembly 80. The electrical signal supplied to the acoustic assembly 80 will cause the distal end to vibrate longitudinally in the range of, for example, approximately 20 kHz to 100 kHz, and preferably in the range of about 54 kHz to 56 kHz, and most preferably at about 55.5 kHz.
The amplitude of the acoustic vibrations at the end effector may be controlled by, for example, controlling the amplitude of the electrical signal applied to the transduction portion 90 of the acoustic assembly by the generator As noted above, the triggering mechanism 36 of the generator 30 allows a user to activate the generator 30 so that electrical energy may be continuously supplied to the acoustic assembly 80. In one embodiment, the triggering mechanism 36 preferably comprises a foot activating switch that is detachably coupled or attached to the generator by a cable or cord 38. In another embodiment, a hand switch may be incorporated in the handpiece assembly 50 to allow the generator 30 to be activated by a user.
The generator 30 also has a power line 38 for insertion in an electrosurgical unit or conventional electrical outlet. It is contemplated that the generator 30 may also be powered by a direct current (DC) source, such as a battery. The generator 30 may be any suitable WO 98/16154 PCT/US97/18652 -9generator, such as Model No. GENO1, available from Ethicon Endo- Surgery, Inc.
Referring still to FIG. 2, the handpiece assembly includes a multi-piece housing or outer casing 52 adapted to isolate the operator from vibration of the acoustic assembly 80. The housing 52 is preferably cylindrically shaped and is adapted to be held by a user in a conventional manner, but may be any suitable shape and size which allows it to be grasped by the user. While a multi-piece housing 52 is illustrated, the housing 52 may comprise a single or unitary component.
The housing 52 of the handpiece assembly 50 is preferably constructed from a durable plastic, such as Ultem®. It is also contemplated that the housing 52 may be made from a variety of materials including other plastics liquid crystal polymer (LCP), nylon, or polycarbonate). A suitable handpiece assembly is Model No. HP050, available from Ethicon Endo-Surgery, Inc.
Referring still to FIG. 2, the handpiece assembly generally includes a proximal end 54, a distal end 56 and a centrally disposed axial opening or cavity 58 extending longitudinally therein. The distal end 56 of the handpiece assembly 50 includes an opening configured to allow the acoustic assembly 80 of the surgical system 10 to extend therethrough. The distal end 56 of the handpiece assembly 50 is also coupled to a catheter 70, and the proximal end 54 of the handpiece assembly 50 is coupled to the generator 30 by a cable 32. The cable 32 may include air ducts or vents 62 to allow air to be introduced into the handpiece assembly 50 to cool the transducer assembly 82 of the acoustic assembly The catheter 70 generally includes an adapter 71 and an elongated flexible catheter body 72. The adapter 71 is coupled to the distal end of the handpiece assembly 50 by a threaded connection 75. It is contemplated that the adapter 71 may be attached to the handpiece assembly 50 by any suitable means.
WO 98/16154 PCT/US97/18652 The catheter body 72 of the catheter 70 has a proximal end, a distal end, and centrally disposed lumen extending longitudinally therethrough. The catheter body 72 may be made from a variety of materials including polyurethane, silicon rubber, or any other suitable material commonly used in conventional catheters. The catheter 70 is configured to permit the catheter body 72 to be inserted into the vascular system of a patient from an entrance site, e.g. a femoral artery or vein, once inserted, the catheter would be guided, for example, to the left ventricle of a heart 14 of a patient.
Referring still to FIG. 2, the acoustic assembly 80 generally includes a transducer stack or assembly 82, a mounting device 84, a flexible transmission rod or wire 86, and an end effector or applicator 88.
The transducer assembly 82, mounting device 84, transmission rod 86, and end effector 88 may be acoustically tuned such that the length of each component is an integral number of one-half system wavelengths (NX/2) where the system wavelength X is the wavelength of a preselected or operating longitudinal vibration frequency f of the acoustic assembly It is also contemplated that the acoustic assembly 80 may incorporate any suitable arrangement of acoustic elements. For example, the acoustic system 80 may comprise a transducer assembly 82 and an end effector 88 the acoustic assembly 80 may be configured without a mounting device and a transmission rod).
The transducer assembly 82 of the acoustic assembly converts the electrical signal from the generator 30 into mechanical energy that results in longitudinal vibratory motion of the end effector 88 WO 98/16154 PCTIUS97/18652 11 at ultrasonic frequencies. When the acoustic assembly 80 is energized, a vibratory motion standing wave is generated through the acoustic assembly 80. The amplitude of the vibratory motion at any point along the acoustic assembly 80 depends on the location along the acoustic system 80 at which the vibratory motion is measured. A minimum or zero crossing in the vibratory motion standing wave is generally referred to as a node where axial motion is usually minimal and radial motion is usually small), and an absolute value maximum or peak in the standing wave is generally referred to as an antinode. The distance between an antinode and its nearest node is one-quarter wavelength As shown in FIG. 2, the transducer assembly 82 of the acoustic assembly 80, which is known as a "Langevin stack," generally includes a transduction portion 90, a first resonator 92, and a second resonator 94. The transducer assembly 82 is preferably an integral number of one-half system wavelengths (NX/2) in length. It is to be understood that the present invention may be alternatively configured to include a transducer assembly 82 comprising a magnetostrictive, electromagnetic, or electrostatic transducer.
The distal end the first resonator 92 is connected to the proximal end of transduction section 90, and the proximal end of the second resonator 94 is connected to the distal end of transduction portion The first and second resonators 92 and 94 are preferably fabricated from titanium, aluminum, steel, or any other suitable material. The first and second resonators 92 and 94 have a length determined by a number of variables, including the thickness of the transduction section 90, the density of material and modulus of elasticity used in the resonators 92 and 94, and the fundamental frequency of the transducer assembly 82. The second resonator 94 may be tapered inwardly from its proximal end to its distal end to amplify the ultrasonic energy vibrational amplitude.
The transduction portion 90 of the transducer assembly 82 preferably comprises a piezoelectric section of alternating positive WO 98/16154 PCT/US97/18652 -12electrodes 96 and negative electrodes 98, with piezoelectric elements 100 between the electrodes 96 and 98. The piezoelectric elements 100 may be fabricated from any suitable material, such as lead-zirconate-titanate, lead meta-niobate, lead titanate, or other ceramic piezoelectric crystal material.
Each of the positive electrodes 96, negative electrodes 98, and piezoelectric elements 100 may have a bore extending through the center.
The positive and negative electrodes 96 and 98 are electrically coupled to wires 102 and 104, respectively. The wires 102 and 104 transmit electrical signals from the generator 30 to the electrodes 96 and 98.
The mounting device 84 of the acoustic system 80 has a proximal end, a distal end, and may have a length substantially equal to an integral number of one-half system wavelengths. The proximal end of the mounting device 84 is preferably axially aligned and coupled to the WO 98/16154 PCTIUS97/18652 13distal end of the second resonator 94 by an internal threaded connection near an antinode. (For purposes of this disclosure, the term "near" is defined as "exactly at" or "in close proximity It is also contemplated that the mounting device 84 may be attached to the second resonator 94 by any suitable means, and that the second resonator 94 and mounting device 84 may be formed as a single or unitary component.
The mounting device 84 may be configured to amplify the ultrasonic vibrational amplitude that is transmitted through the acoustic assembly 80 to the distal end of the end effector 88. In one preferred embodiment, the mounting device 84 preferably comprises a solid, tapered horn. As ultrasonic energy is transmitted through the mounting device 84, the velocity of the acoustic wave transmitted through the mounting device 84 is amplified. It is contemplated that the mounting WO 98/16154 PCT/US97/18652 14device 84 may be any suitable shape, such as a stepped horn, a conical horn, an exponential horn, or the like.
The transmission rod 86 and end effector 88 of the surgical system 10 are preferably made from a solid core shaft constructed of material, such as a titanium alloy Ti-6A1-4V) or an aluminum alloy, which propagates ultrasonic energy efficiently. The transmission rod 86 and end effector 88 may be fabricated from any suitable material. It is also contemplated that the end effector 88 may have a surface treatment to improve the delivery of energy and desired tissue effect. For example, the end effector 88 may be micro-finished, coated, plated, etched, gritblasted, roughened or scored to increase surface friction in order to enhance coagulation in tissue. The end effector 88 may also have a distal section having smaller cross-section area than a proximal section forming a vibrational amplitude step-up junction. When the transducer assembly 82 is energized, the distal end of the end effector 88 is configured to move longitudinally in the range of, for example, approximately 10 to 500 microns peak-to-peak and preferably in the range of about 30 to 100 WO 98/16154 PCT/US97/18652 microns at a predetermined vibrational rate and most preferably at about microns.
The transmission rod 86 and end effector 88 may, for example, each have a length substantially equal to an integral number of half wavelengths In one embodiment, the transmission rod 86 has a diameter in the range of about 0.5-1mm and the end effector 88 has a diameter in the range of about 0. lmm-5mm. The transmission rod 86 preferably has a diameter of 0.5mm and the end effector 88 preferably has a diameter of about 0.5mm-2mm. Most preferably, the transmission rod 86 has a diameter of 0.5mm and the end effector 88 has a diameter of about 1mm. It is also contemplated that the transmission rod 86 and end effector 88 may be any suitable diameter.
As shown in FIG. 3, the tip 150a of the end effector 150 has a substantially round configuration. With this arrangement, the tip 150a of the end effector 150 can create channels in the heart of a patient while minimizing trauma, tissue damage, and cutting. In FIG. 4, the tip 152a of the end effector 152 has a substantially pointed or conical shape.
With this configuration, the tip 152a can be utilized to minimize trauma and allow for easier tissue penetration when creating channels in the heart of the patient. In FIG. 5, the tip 154a of the end effector 154 has a substantially blunt, flat, or square configuration. With this embodiment, the tip 154a of the end effector 154 can minimize tissue displacement and WO 98/16154 PCT/US97/18652 -16maximize tissue cutting and removal when creating channels in the heart of the patient. In FIG. 6, the tip 156a of the end effector 156 has a substantially beveled or tapered configuration. The edges at the juncture of the sides of the tapered section of the tip 156a provide narrow cutting edges and the broad surfaces therebetween increase the amount of energy delivered by the edges to increase coagulation or hemostasis.
Referring now to FIG. 7, the tip 158a of the end effector 158 has a substantially pyramidal configuration or triangular crosssection. The edges at the juncture of the sides of the triangular-shaped tip 158a provide narrow cutting edges to facilitate penetration and advancement, while the broad surfaces therebetween afford coagulation surfaces when creating channel in the heart of the patient. In FIG. 8, the tip 160a of the end effector 160 has multiple steps 162 to maximize tissue removal when creating channels in the heart of the patient. In FIG. 9, the tip 164a of the end effector 164 has a stepped shoulder 166 having any suitable shaped end 168. The stepped shoulder 166 can be used as a indicator of penetration depth and to prevent over insertion. The stepped shoulder 166 preferably provides additional amplification of the ultrasonic vibration and amplitude to increase cutting. A stepped shoulder such as 166 may be employed in conjunction with any of the end effectors illustrated in FIGS. 3-11 or in any other suitable end effector.
The use of the surgical system 10 will now be described with reference to FIGS. 1 and 2. Initially, the surgical system 10 is WO 98/16154 PCTIUS97/18652 -17connected to the generator 30 in an unarmed state. The generator 30 then measures the initial parameters of the acoustic assembly 80 and arms the system. The surgical system 10 is then in a ready state, at which point the surgeon may position the catheter at the desired site within the body and then trigger the generator 30 using the triggering mechanism 36.
In one method of treating a patient, the catheter body 72 of the handpiece assembly 50 is inserted into a vein or artery in a cardiovascular system of a patient. The catheter 70 is manipulated through the vessel of a patient into, for example, the left ventricle of the heart 14 of a patient until the distal end of the end effector 88 reaches a desired location. The catheter body 72 may be inserted into a femoral artery and advanced through the aorta into the left ventricle via the aortic valve. Alternatively, the catheter 70 may be inserted into the femoral vein and advanced to the right side of the heart where the catheter enters the left ventricle transeptically. The catheter 70 may use a guide wire to guide the catheter through the cardiovascular system of the patient to the desired treatment area. The catheter 70 may also be visually monitored by the physician using fiber optics or may be viewed by ultrasound imaging or fluoroscopic imaging.
Once the end effector 88 is properly positioned near the inner wall 16 of the heart 14, the user may activate the generator 30 to cause the end effector 88 to vibrate. The distal end of the end effector 88 may then be advanced to tunnel or burrow through the inner wall 16 of the heart 14 to form a channel 12 into the myocardium 18 of the heart 14.
As the distal end of the end effector 88 contacts tissue and couples vibrational energy to the tissue, heat is generated in the tissue to break protein hydrogen bonds, causing the highly structured protein to denature.
The energized distal end of the end effector 88 generates thermal energy, mechanical pressure, and cavitation in the tissue which causes the end effector 88 to penetrate the tissue and create channels in the wall of the heart. After the end effector is advanced a desired distance into the inner WO 98/16154 PCT/US97/18652 -18wall, the end effector 88 is then withdrawn. In the present method, the distal end of the end effector 88 preferably does not penetrate through the outer wall of the heart.
A plurality of channels may be formed through the inner wall 16 of the ventricle chamber and into the myocardium 18.
Preferably, the channels are approximately lmm in diameter. These channels provide a flow path for blood into the myocardium 18 from the ventricular chamber 20. It is contemplated that any suitably sized diameter may be formed through the inner wall 16 without departing from the spirit and scope of the present invention.
The housing 236, finger grip 238, and thumb grip 240 are preferably constructed from a durable plastic, such as Ultem®. It is also contemplated that these components may be made from a variety of WO 98/16154 PCTIUS97/18652 19materials including other plastics liquid crystal polymer (LCP), nylon, or polycarbonate).
The transducer assembly 252 of the acoustic assembly 250 generally includes a transduction portion 255, a first resonator 256, and a second resonator 258. The transducer assembly 252 is preferably an WO 98/16154 PCT/US97/18652 integral number of one-half system wavelengths (NX/2) in length. It is also contemplated that the acoustic assembly 250 may be any suitable arrangement of acoustic elements. For example, the acoustic assembly 250 may comprise a transducer assembly, a mounting device, a transmission rod, and an end effector as described above. It is to be understood that the present invention may be alternatively configured to include a transducer assembly comprising a magnetostrictive, electromagnetic or electrostatic transducer.
The distal end of the first resonator 256 is connected to the proximal end of transduction portion 255, and the proximal end of the second resonator 258 is connected to the distal end of transduction portion 255. The first and second resonators 256 and 258 are preferably fabricated from titanium, aluminum, steel, or any other suitable material.
The second resonator 258 is preferably tapered inwardly from its proximal end to its distal end to amplify the ultrasonic vibration amplitude.
The transduction portion 255 of the transducer assembly 252 preferably comprises a piezoelectric section of one or more alternating positive electrodes 260 and negative electrodes 262, with piezoelectric elements 264 alternating between the electrodes 262 and 264. The piezoelectric elements 264 may be fabricated from any suitable material, such as lead-zirconate-titanate, lead meta-niobate, lead titanate, or other ceramic piezoelectric crystal material. The piezoelectric elements 264 are energized in response to the electrical signal supplied from the generator 220 to produce an acoustic standing wave in the acoustic assembly 250 as described above.
The transducer assembly 252 is operatively coupled to the generator 220 via a cable 224 enclosing one or more wires 270 and 272.
The wires 270 and 272 are connected to positive electrodes 260 and negative electrodes 262, respectively. The transducer assembly 252 is substantially similar to the transducer assembly described above except WO 98/16154 PCT/US97/18652 -21 that it is reduced in size. As such, further description of the transducer assembly 252 is unnecessary for a complete understanding of the invention. It is to be also understood that the present invention may be alternatively configured to include a transducer assembly 252 comprising a magnetostrictive, electromagnetic, or electrostatic transducer.
The end effector 254 of the acoustic assembly 250 has a proximal end, a distal end, and may have a length substantially equal to an integral number of one-half system wavelengths The proximal end of the end effector 254 is preferably coupled to the distal end of the second resonator 258 by an internal threaded connection near an antinode.
It is also contemplated that the end effector 254 may be attached to the second resonator 258 by any suitable means, and that the second resonator 258 and end effector 254 may be formed as a single or unitary component.
As shown in FIG. 13, the end effector 254 preferably has a distal region 254a having a smaller cross-section area than a proximal region 254b thereof, thereby forming a vibrational amplitude step-up junction 254c. The step-up junction 254c acts as a velocity transformer as known in the art, increasing the magnitude of the ultrasonic vibration transmitted from the proximal region 254a to the distal region 254b of the end effector 254. The end effector 254 is preferably fabricated from a titanium alloy, such as Ti-6A1-4V. It is contemplated that the end effector 254 may be manufactured from any suitable material without departing from the spirit and scope of the invention.
The end effector 254 may preferably have a length of an integral multiple of half wavelengths (NX/2) in order to produce the maximum longitudinal deflection at its remote end. The end effector 254 has a diameter of about .1-5mm, and preferably a diameter of about 2mm, and most preferably a diameter of 1mm. The end effector 254 may have any suitable configuration, such as the arrangements shown in FIGS.
3-11 as described above.
WO 98/16154 PCT/US97/18652 -22- As shown in FIG. 13, a plurality of seals 265 are distributed along the lumen of the catheter body 234 to support the transducer assembly 252. The seals 265 are preferably fabricated from silicone to isolate the catheter body 234 from the transducer assembly 252. As those skilled in the art will recognize, the transducer assembly 252 or acoustic assembly 250 may be supported by any suitable means. It is also contemplated that the catheter body 234 may be configured to attach to a housing that holds the transducer assembly 252. For example, a housing may be mounted at or near the distal end of the catheter body 234. Alternatively, the catheter body 234 may have a first section and a second section with a housing disposed therebetween to support the transducer assembly.
Although the present invention has been described in detail by way of illustration and example, it should be understood that a wide range of changes and modifications can be made to the preferred embodiments described above without departing in any way from the scope and spirit of the invention. Thus, the described embodiments are to be considered in all respects only as illustrative and not restrictive, and the scope of the invention is, therefore, indicated by the appended claims rather than the foregoing description. All changes that come within the WO 98/16154 PCTIUS97/18652 -23 meaning and range of equivalency of the claims are to be embraced within their scope.
1. A method of improving blood flow in a heart of a patient comprising the steps of: inserting a catheter in a cardiovascular system of the patient; advancing the catheter through the cardiovascular system until it is positioned in a left ventricle of the heart of the patient; vibrating a distal end of an acoustic assembly at an ultrasonic frequency; contacting the heart with the distal end of the acoustic assembly to create a channel of a selected depth in the inner surface of the heart; and withdrawing the distal end of the acoustic assembly from the heart. *e
2. The method of claim 1 further repeating the steps of 15 advancing, contacting and withdrawing to form a plurality of channels in the heart.
3. A method of improving the blood flow to a heart of a patient comprising the steps of: 20 providing a catheter carrying an end effector having a distal end; vibrating the distal end of the end effector at a selected frequency; contacting the distal end of the end effector with a ventricular wall of a heart; advancing the distal end of the end effector assembly into the ventricle wall; creating a channel in the ventricular wall with the distal end; and removing the end effector from the ventricle wall. RNM:JH:4034992.MODEXM 21 February 2001
5. The method of claim 3 wherein the frequency is between kHz and 100 kHz.
6. The method of claim 1 wherein the step of forming a channel is accomplished without synchronizing to a heartbeat of a patient. DATED: 21 February 2001 FREEHILLS CARTER SMITH BEADLE .e 15 Patent Attorneys for the Applicant: ETHICON ENDO-SURGERY, INC e* *e *o RNM:JH:4034992.MODEXM 21 February 2001
AU50804/98A 1996-10-17 1997-10-16 Methods and devices for improving blood flow to a heart of a patient Ceased AU733020B2 (en)
US733128 1996-10-17
US770319 1996-12-20
AU5080498A AU5080498A (en) 1998-05-11
AU733020B2 true AU733020B2 (en) 2001-05-03
AU50804/98A Ceased AU733020B2 (en) 1996-10-17 1997-10-16 Methods and devices for improving blood flow to a heart of a patient
US5989274A (en) 1999-11-23