Ultrasonic method for ablating and removing obstructive matter from anatomical passageways and blood vessels

[0002] This application is a divisional of U.S. application Ser. No. 08/815,673 filed Mar. 12, 1997, now U.S. Pat. No. 5,957,882, which is a continuation of U.S. application Ser. No. 08/222,999 filed Apr. 5, 1994, now abandoned and a continuation-in-part of application Ser. No. 07/640,190, field Jan. 11, 1991, now U.S. Pat. No. 5,304,115.

[0003] Incorporated by reference are U.S. Pat. No. 5,304,115 to Pflueger et al. and U.S. Pat. No. 5,267,954 to Nita.

[0004] The present invention pertains generally to medical equipment and, more particularly, to ultrasonic devices and methods for removing obstructive matter from anatomical passageways, including the removal of obstructive matter from the cerebral vasculature, prostate tissue from the urinary tract and/or obstructive matter from the fallopian tubes.

[0005] The prior art has included various ultrasonically vibrated surgical and ablative instruments for treating obstructive disorders of blood vessels and other anatomical passageways or cavities.

[0006] The prior art devices which purportedly utilize ultrasonic energy, alone or in conjunction with other treatment modalities, to treat obstructions within blood vessels or other anatomical structures of the body-include those described in U.S. Pat. Nos. 3,433,226 (Boyd), 3,823,717 (Pohlman, et al.), 4,808,153 (Parisi), 4,936,281 (Stasz), 3,565,062 (Kuris), 4,924,863 (Sterzer), 4,870,953 (Don Michael, et al.), 4,920,954 (Alliger, et al.), and 5,100,423 (Fearnot), 4,136,700 (Broadwin), 4,192,294 (Vasilevsky), 4,750,448 (Wuchinich), 4,750,902 (Wuchinich), 4,765,332 (Fischell), 4,808,153 (Parisi), 4,832,023 (Murphy-Chutorian), 4,867,141 (Nakada), 4,870,953 (Don Michael), 4,877,033 (Seitz), 4,886,061 (Fischell), 4,922,902 (Wuchinich), 4,936,281 (Stasz), 4,974,581 (Wiksell), 4,989,588 (Kubota), 5,058,570 (Idemoto), 5,069,664 (Guess), 5,149,319 (Unger), 5,151,084 (Khek), 5,154,723 (Kubota), 5,156,143 (Bocquett), 5,163,421 (Bernstein), 5,163,433 (Kagawa), as well as foreign publications nos. WO87-05739 (Cooper), WO89-06515 (Bernstein, et al.), WO90-0130 (Sonic Needle Corp.), EP316789 (Don Michael, et al.), DE3,821,836 (Schubert), DE2,438,648 (Pohlman), GB 1,531,659 (Gekhman, et al.), EP 342448 (Bakelite), EP 293472 (Bakelite), and EP 209468 (Sarl).

[0007] Although the prior art has included numerous devices for ultrasonic treatment of intracorporeal obstructions, there remains a need in the art for the development of new and improved ultrasonic devices having improved or differing capabilities for specific blood vessels or regions of the body, such as the intracranial and extracranial vessels of the cerebral vasculature and/or the tubes and ducts of the genitourinary tracts of the male and female.

[0008] The present invention provides methods for ultrasonically treating obstructions of anatomical passageways of the mammalian body with concomitant infusion of a fluid (e.g., saline solution) in a manner which will dilate or fluidically expand the surrounding anatomical structure so as to facilitate passage of a catheter through the obstructed region of the anatomical structure. Methodologies in accordance with this embodiment of the invention are particularly useful in treating intravascular obstructions as well as obstructions of the male or female urogenital tract, including, but not limited to obstructions of the fallopian tubes and prostatic obstructions of the male urethra.

[0009] Further in accordance with the invention, there are provided methods for ultrasonically treating obstructions within anatomical passageways of the mammalian-body while concomitantly aspirating and removing matter from the anatomical passageway so as to prevent escape of solid particles or other matter created or released by the ultrasonic treatment process. In accordance with this embodiment of the invention, there are provided methodologies which are particularly applicable in the ultrasonic treatment of obstructions within intracranial and extracranial cerebral blood vessels which supply blood to the mammalian brain.

[0010] Further in accordance with the invention, there is provided a first embodiment of an ultrasound treatment system incorporating an ultrasound delivery catheter having one or more fluid infusion lumens for infusing fluid through the catheter, to effect fluidic dilation of the anatomical structure wherein the obstruction is located.

[0011] Still further in accordance with the invention, there is provided a second embodiment of an ultrasound treatment system incorporating an ultrasound delivery catheter having at least one aspiration lumen extending longitudinally through the catheter to aspirate and remove particles or other debris from the anatomical structure wherein the obstruction is located.

[0012] Further objects and advantages of the invention will become apparent to those skilled in the art upon reading and understanding the following detailed description and the accompanying. drawings.

[0013] FIG. 1 is a perspective view of a first embodiment of an ultrasonic system of the present invention for removing obstructions from genitourinary pathways or other anatomical structures of the body.

[0014] FIG. 2 is an enlarged perspective view of a first embodiment of a distal catheter tip which may be incorporated in the system of FIG. 1.

[0015] FIG. 3 is a longitudinal sectional view through line 3—3 of FIG. 2.

[0016] FIG. 4 is a cross-sectional view through line of 4—4 FIG. 3.

[0017] FIG. 5 is an enlarged perspective view of a second embodiment of a catheter tip which may be incorporated into the ultrasound system of FIG. 1.

[0018] FIG. 6 is a longitudinal sectional view through line 6—6 of FIG. 5.

[0019] FIG. 7 is a cross-sectional view through line 7—7 of FIG. 6.

[0020] FIG. 8 is a perspective view of an alternative configuration of an ultrasound treatment system of the present invention.

[0021] FIG. 9 is an enlarged perspective view of a distal catheter tip which may be incorporated into the ultrasound system of FIG. 8.

[0022] FIG. 10 is a longitudinal sectional view through line 10—10 of FIG. 9.

[0023] FIG. 11 is a cross-sectional view through line 11—11 of FIG. 10.

[0024] The following detailed description and the accompanying are provided for purposes of describing and illustrating presently preferred embodiments of the invention and are not intended to cover every possible embodiment or configuration of the invention, nor are they intended to limit the scope of the accompanying claims in any way.

[0025] With references to the drawings, FIGS. 1-7 are directed to a first embodiment of the invention preferably useable to dilate and treat obstructive disorders of various anatomical passageways, including the urethra and/or fallopian tubes. FIGS. 8-11 are directed to a second embodiment of the invention preferably useable to effect a) ultrasonic ablation of obstructive matter and b) aspiration of the reduced or morseled matter from the treatment site, such as a cerebral blood vessel or other passageway of the body wherein prompt aspiration or removal of any solid matter is desired.

[0026] A first embodiment of an ultrasound treatment system 10 of the present invention, shown in FIG. 1, comprises an electrical signal generator 12 (e.g., Model UAG-1110, Baxter Healthcare Corporation, Cardiovascular Group, Interventional Cardiology Division, Irvine, Calif.) connected by way of cable 13 to an ultrasound transducer 14 (e.g., Model UAT-1000, Baxter Healthcare Corporation, Irvine, Calif.) operable to convert the electrical signal from the signal generator 12, into ultrasonic vibration. An elongate ultrasound catheter 16 is coupled to the ultrasound transducer 14 to transmit ultrasonic vibration from the transducer 14 to a desired treatment location adjacent the distal end of the catheter 16.

[0027] The catheter 16 component of the first embodiment of the ultrasound treatment system 10 may comprise an elongate flexible catheter body 18 formed of pliable material and an elongate ultrasound transmission wire or member 20 which extends longitudinally through the catheter body 18. The ultrasound transmission wire or member 20 extends proximally through a proximal connector assembly 22 whereby the proximal end of the ultrasound transmission member 20 may be coupled or attached to the ultrasound generating horn of the ultrasound transducer 14. The distal end of the ultrasound transmission member 20 is coupled or attached to a distal head member 30 at the distal end of the catheter 16.

[0028] The structure and configuration of the proximal connector assembly 22 of the first embodiment may be the same as that described and shown in FIG. 10 of U.S. Pat. No. 5,267,954 (Nita), the entirety of such patent being hereby expressly incorporated herein by reference.

[0029] A fluid infusion sidearm 24 extends from proximal connector assembly 22 and is fluidly communicative with a hollow bore extending through at least a distal portion of the proximal connector assembly 22 and into an elongate hollow infusion fluid lumen 26 extending through the catheter body 18. A source 28 of pressurized or pumped liquid (e.g., 0.9% NaCl solution) is connected to the fluid infusion sidearm 24 to permit infusion of fluid through the bore of the proximal connector assembly 22 and through the elongate lumen 26 of the catheter body 18. A distal head member 30, is mounted on the distal end of the catheter body 18. Such distal head member may be of any suitable configuration, including the blunt horizontal faced configuration 30ashown in FIGS. 2-3 and the bullet-like configuration 30bshown in FIGS. 5-6. In any case, the distal head member 30 will be provided with one or more fluid outflow apertures 34 which are fluidly communicative with the fluid lumen 26 of the catheter body 18 to permit irrigation fluid to flow out of the distal head 30 of the catheter 16.

[0030] In the blunt distal head embodiment 30 shown in FIGS. 2-3, the configuration of the distal head member 30 is such that there is provided a frontal portion 36 having an outer diameter substantially equal to the outer diameter of the catheter body 18, and a rear portion 38 having an outer diameter substantially equal to the inner diameter at the distal head of the catheter lumen 26 by such configuration, the rear portion 38 of the distal head member 30 may be inserted into the distal end opening of the lumen 26 of catheter body 18 and secured thereto by frictional engagement, mechanical engagement, adhesive, heat sealing or other suitable means. The outer surface of the frontal portion 36 of the distal head member 30ais thus rendered substantially continuous and in smooth transition with the outer surface of the adjacent catheter body 18. The distal head member 30ahas a central fluid passageway 32 formed therein,. separate and apart from the guidewire passageway 40 which extends longitudinally through the lower portion of the distal head member 30. Such central fluid passageway 32 opens into ancillary passageways 42, said ancillary passageways 42 terminating laterally in the multiple fluid outflow apertures 34 formed in the sides of the distal head member 30. By such arrangement, fluid infused through the lumen 26 of the catheter body 18 will enter the central fluid passageway 32 of the distal head member 30 and will subsequently pass outwardly through the lateral fluid passageways 42 and out of the fluid outflow apertures 34. This may be accomplished while a guidewire (phantom lines) remains inserted into guidewire passageway 40, thereby substantially blocking fluid outflow through. guidewire passageway 40.

[0031] The rate of fluid outflow through outflow apertures 34 may be controlled to effect any desired degree of irrigation and/or fluidic dilation of a surrounding anatomical structure (e.g., fallopian tube, ureter, duct, blood vessel, etc. . . . )

[0032] The alternative distal head configuration 30bshown in FIGS. 5-7 provides a distal head member 30bhaving a frontal portion 36band a rear portion 38b. Said frontal portion 36bhaving an outer diameter substantially equal to the outer diameter of the adjacent catheter body 18. Said rear portion 38bhas an outer diameter substantially equal to the inner diameter of the distal end of the catheter lumen 26. By such configuration, the rear portion 38bof the distal head member 30bmay be inserted into the distal end of the catheter lumen 26band secured thereto by frictional engagement, mechanical engagement, heat sealing, chemical adhesive, or any other suitable means. When so constructed, the lateral outer surface of the distal head member 30bis continuous, and substantially flush with the adjacent outer surface of the catheter body 18, as shown. The alternative distal head member 30b. shown in FIGS. 5-7 also differs from the distal head member 30ashown in FIGS. 2-4 in that the guidewire passageway 40bserves as the central fluid passageway of the distal head 30b, as well as serving as the guidewire passageway through which a guidewire may pass longitudinally through the distal head member 30b(see guidewire shown in phantom lines).

[0033] Fluid outflow passageways 42bpass fluid laterally outward from the central guidewire lumen fluid passageway 40band lead to multiple fluid outflow apertures 34b. Thus, when the guidewire (phantom lines). has been removed or retracted so as not to block fluid entry into the guidewire passage lumen/central fluid passageway 40b, irrigation/dilation/coolant fluid may be infused through the lumen 26bof the catheter body 18, through the guidewire passageway/central fluid passageway 40band subsequently outward through the lateral fluid passageways and lateral fluid outflow apertures 34b, as well as through the frontal guidewire passageway opening 40b. The flow rate and volume of fluid so infused may be controlled to effect any desired degree of irrigation or dilation of a surrounding anatomical structure (e.g., fallopian tube, ureter, blood vessel or other anatomical passageway).

[0034] The ultrasound system 10 of the first embodiment shown in FIGS. 1-7 may be utilized for ultrasonic-treatment of various obstructive disorders of the mammalian body wherein it is desirable to effect concomitant fluid irrigation or fluid dilation of the anatomical structure whereat the distal end of the catheter 18 is positioned.

[0035] Examples of procedures wherein the ultrasound system 10 of the first embodiment may be employed, include the ultrasonic ablation of atherosclerotic plaque, thrombus or other obstructive matter within the lumen(s) of mammalian blood vessel(s). Also, as described more fully in the examples set forth herebelow, the ultrasound system 10 of the first embodiment may be utilized to effect dilation and/or removal of obstructive matter (e.g., scar tissue, tumors, congenitally aberrant tissue,. etc. . . . ) which obstruct tubular passageways of the body including the ducts and passageway of the urogenital tract (e.g., urethra, ureter, fallopian tubes).

[0036] In a first example, an ultrasound system 10 of the first embodiment of the present invention may be utilized to treat obstructions of the fallopian tubes of a female human being.

[0037] Fallopian tube obstructions are known to occur due to the formation of scar tissue within the lumens of the fallopian tubes following the occurrence of fallopian tube infections, such as chlamydia infections.

[0038] In treating such blockage of the fallopian tubes, a standard guidewire having an outer diameter of approximately 0.14÷0.25 inch is inserted transvaginally and advanced, with radiographic and/or endoscopic guidance, into the obstructed fallopian tube to a point where the distal end of the guidewire 50 is situated adjacent the offending fallopian tube obstruction. After the guidewire has been positioned, the proximal end of the guidewire 50 is inserted into the distal guidewire passageway 40 of the catheter 18 and the catheter 18 is advanced over the guidewire, using standard catheter advancement technique, to a point where the distal head 30 of the catheter 18 has been advanced to a position adjacent the obstruction to be treated. During such advancement of the catheter, the proximal end of the guidewire 50 will emerge out of the guidewire sidearm 52 of the proximal connector assembly 22 so as to render the proximal portion of the guidewire freely accessible to the operator for subsequent manipulation, extraction or exchange of the guidewire 50, if desired.

[0039] The pressurized fluid source or pump 28 is then utilized to pass a flow of irrigation/dilation fluid, such as 0.9% NaCl solution or other physiologically compatible liquid, through line 56 and into sidearm 24 of proximal end connector assembly 22. The fluid so infused will then pass, in the distal direction, through the internal bore of the proximal connector assembly 22, through the lumen 26 of catheter 18 and out of the fluid outflow apertures 34 of the distal head 30 of the catheter device 16.

[0040] The flow rate of irrigation/dilation fluid out of outflow apertures 34 may be adjusted and controlled so as to provide a controlled degree of a) fluid-induced dilation of the fallopian tube lumen immediately adjacent the obstruction to be treated and/or b) impingement of fluid against the obstructing scar tissue or other matter.

[0041] Thereafter, the signal generator 12 may be energized by depression of on/off foot pedal 11, thereby sending an electrical signal through line 13 to ultrasound transducer 14. Such electrical signal is converted to ultrasonic vibration by ultrasound transducer 14 and the ultrasonic vibration is passed, via proximal connector assembly 22, into the ultrasound transmission wire or member 20, thereby causing ultrasonic vibration of the distal head 30 of the catheter 16.

[0042] With continued infusion of the irrigation/dilation fluid, the catheter 16 may be advanced, or otherwise moved back and forth, such that the ultrasonic vibration of the distal head 30 of the catheter 16 will effect morcellation or reduction of the obstructive matter. Such morcellation or reduction of the obstructive matter by the ultrasonic vibration of the distal head 30 may be effected by direct contact of the vibrating distal head 30 against the obstructive matter and/or by cavitation effect created as a result of the ultrasonically vibrating distal head 30 in the fluid environment created by the controlled infusion of the infusion/dilation fluid adjacent the obstructive lesion to be treated.

[0043] In some cases, it may be desirable to initially employ a first catheter 16 having a distal head 30 designed for initial dilation of the surrounding fallopian tube lumen and impingement of the irrigation fluid against the offending lesion, and to subsequently utilize one or more additional embodiments of the catheter 16 having different designs of the distal head 30 so as to effect differing degrees of fluid impingement against the offending lesion and/or fluidic dilation of the surrounding luminal wall of the fallopian tube, during differing stages of the procedure. For example, in some procedures it may be desirable to utilize three(3) separate catheter devices 16, as follows:

[0044] In addition to effecting ultrasonic ablation or breakdown of the obstructive matter, the ultrasonic vibration of the distal head 30 of the catheter 16 may also cause relaxation of smooth muscle and resultant dilation of the fallopian tube, thereby permitting the catheter 16 to be advanced back and forth through the previously obstructed region of the fallopian tube.

[0045] In this example, it is preferable that t e ultrasonic vibration of the distal catheter tip 30 be of an optimized frequency and wave form modulation to effect the desired ablation of the obstruction for inducing smooth muscle relaxation and resultant dilation of the obstructed fallopian tube.

[0046] One or more inflatable dilation balloons mounted on the ultrasound catheter device 16 or mounted on a separate balloon catheter may be utilized in conjunction with the ultrasound catheter 16, to effect dilation and opening of the obstructed region of the fallopian tube.

[0047] After the procedure has been completed and the patency of the obstructed fallopian tube restored, the catheter 16 may be extracted and removed.

[0048] In a second example, the ultrasound system 10 of the first embodiment of the present invention may be utilized to treat obstructions of the male urethra resulting from benign prostatic hypertrophy or other prostate enlargement.

[0049] In this example, the catheter device 16 of the first embodiment is inserted, with or without the assistance of a pre-inserted guidewire 50, into the male urethra. The catheter 16 is then advanced to a point where the distal head 30 of the catheter 16 is positioned adjacent the obstructing prostatic tissue.

[0050] A pressurized fluid source or pump 28 may be utilized to pump or otherwise expel fluid through tube 54, through sidearm 24, through the longitudinal bore of the proximal connector assembly 22, through the lumen 26 of catheter 16 and out of the distal fluid outflow-apertures 34. The flow rate and quantity of the irrigation/dilation fluid being infused may be specifically adjusted and/or controlled so as to effect the desired degrees of a) impingement of the fluid against the obstruction and/or b) fluidic dilation of the surrounding anatomical structures (e.g., the urethra).

[0051] Concomitant with the infusion of the irrigation/dilation fluid, signal generator 12 may be energized by depression of on/off foot pedal 11, thereby sending an electrical signal through line 13 to ultrasound transducer 14. Ultrasound transducer 14 will convert the electrical signal to ultrasonic vibration and, via proximal connector assembly 22, will pass such ultrasound vibration through ultrasound transmission member 20 to the distal head 30 of the catheter 16. Ultrasonic vibration from the catheter tip may thereby result in a) relaxation and dilation of the smooth muscle of the urethra and/or b) ultrasonic ablation or morselling of the obstruction.

[0052] For smooth muscle relaxation the preferred ultrasound frequency is 20 kz to 1 MHz. For morselling or ablating the obstructing prostate tissue, the preferred ultrasound frequency is 20 kz to 100 MHz.

[0053] As described above in Example 1, it may also be desirable to utilize two or more separate catheters 16 having distal heads 30 of differing design, with different positions and configurations of the fluid outflow apertures 34, to facilitate optimal performance of various phases of the procedure.

[0054] After the prostatic obstruction of the urethra has been ultrasonically ablated and/or dilated so as to restore patency and urinary flow through the urethra, the catheter 16 may be extracted and removed.

[0055] The foregoing Examples 1 and 2 are intended to illustrate certain specific intended applications of the ultrasound system 10 of the first embodiment of the invention, and are not intended to provide a comprehensive discussion of all possible ablative or dilative procedures wherein the ultrasound system 10 may be employed.

[0056] FIGS. 8-11 of the drawings are directed to a second embodiment of an ultrasound system 10aof the present invention. As shown, such second embodiment ultrasound system 10agenerally comprises a signal generator 12a, an ultrasound transducer 14aand an elongate catheter 16a, having a proximal connector assembly 22apositioned on the proximal end thereof for coupling the catheter 16ato the ultrasound transducer 14a.

[0057] The proximal connector assembly 22aof the second embodiment ultrasound system 10amay be constructed and configured substantially the same as that described hereabove and in incorporated U.S. Pat. No. 5,267,954 (Nita), however it will be appreciated -that in accordance with the showing of the second embodiment in FIG. 8 of this patent application such ultrasound connector assembly 22awill include an additional suction or aspiration sidearm 60 and a separate suction or aspiration tube or secondary lumen (not shown) within the hollow bore of the connector assembly 22aand which is continuous with and fluidically connected to an aspiration lumen or tube member to which extends longitudinally through the catheter body 18afor withdrawal or aspiration of debris.

[0058] The catheter 16apreferably comprises an elongate flexible catheter sheath having an ultrasound transmission member or wire 20aextending longitudinally therethrough. The proximal end of the ultrasound transmission member or wire 20aextends proximally through the proximal connector assembly 22aand is thereby coupleable or connectable to the ultrasound transducer 14a. The distal end of the ultrasound transmission member wire 20ais coupled or connected to the distal head members of 30athe catheter 16aso as to transmit ultrasonic vibration into the distal head member 30a.

[0059] The catheter 16aof the second embodiment shown in FIG. 8-11 is a “monorail” type of catheter having a guidewire passage lumen 51 extending only through a distal portion of the catheter body 18a. In the embodiment shown, the guidewire passage lumen 51 comprises a tube which extends from the distal guidewire passage aperature 40aformed in the distal end of the distal head member 30ato a sidewall guidewire passage aperture 41aformed in the sidewall of the catheter body 18a, at a location such as that shown in FIG. 8. By such “monorail” arrangement, the proximal end of a guidewire may be passed into distal guidewire aperture 40cand advanced through guidewire lumen 51 so as to subsequently exit the catheter body 18athrough sidewall aperture 41a: The proximal portion of the guidewire 50 may reside outboard of the catheter body 18aas is typical of “monorail” type catheters.

[0060] It will be appreciated that an over-the-wire embodiment may also be designed incorporating a guidewire tube or lumen which extends longitudinally through the entire catheter body 18a, with a separate guidewire passage sidearm formed in the proximal connector 22a, in a manner similar or the same as that shown in FIG. 1 with respect to the first embodiment described hereabove.

[0061] An aspiration tube member 70 extends longitudinally through the internal bore 26aof the catheter body 18aand longitudinally through a separate dedicated bore formed in the distal head member 30aas shown. The distal end of the aspiration tube member 70 is flush with the distal or frontal face of the distal head member 30a. The proximal end of the aspiration tube member 70 is fluidly connected or continuous with aspiration sidearm 60, thereby forming a continuous dedicated aspiration channel through the catheter 16a. Aspiration pump 62 is connected to aspiration sidearm 60 by way of tube 64. Debris collection vessel 66 is connected to aspiration pump 62 by tube 68. By such arrangement, aspiration pump 62 may be utilized to withdraw or aspirate debris from the area adjacent the distal end of the catheter, in a proximal direction, through aspiration tube member 70 and into debris collection vessel 66.

[0062] With reference to FIGS. 8-11, the ultrasound system 10aof the second embodiment may be operated to effect ultrasonic dilation, morselling, pulverization or other treatment of obstructive matter within a vessel or passageway of a mammalian body. Concomitant with or separate from the ultrasonic treatment, the system 10amay also be utilized to a) infuse irrigation/coolant/dilation fluid through the catheter 16aand out of the distal end thereof and b) aspirate debris, fluid or other matter, in a proximal direction, through the catheter 16aand into the debris collection vessel 66.

[0063] The aspiration and debris collection capability of the system 10aof the second embodiment is particularly useful in applications wherein it is desired to promptly remove or suction away any particles of solid matter which may be created or liberated as a result of the ultrasonic treatment process. The ability to aspirate and suction away debris or particles of solid matter is particularly important in vascular applications, wherein it is desirable to avoid any embolization or migration of solid matter into the organ or tissue, which is perfused by the blood vessel wherein the treatment is being applied. For example, in procedures wherein ultrasound is utilized to treat or ablate obstructions of the extracranial and/or intracranial blood vessels which profuse the brain, it is highly desirable to prevent the passage of any solid particulate matter into the brain, as such may result in highly undesirable sequelae such as iatrogenic stroke or embolization of smaller blood vessels which may be situated downstream from the site of the treatment procedure. In such cerebrovascular applications, the ability to promptly aspirate any solid particles which may have been created or released by the ultrasonic procedure is useful to prevent such solid particles from resulting in untoward embolization of the brain.

[0064] Arterial blood flow to the brain is provided mainly by four(4) large extracranial arteries, two common carotid arteries and two(2) vertebral arteries, which feed smaller intracranial arteries. The two(2) vertebral arteries originate from the right and left subclavian arteries, respectively, and pass into the cranium through the foramen magnum. The vertebral arteries give off branches to form the anterior spinal artery, the posterior and inferior cerebellar arteries, and the basilar artery. The common carotid arteries bifurcate into the internal and external carotid arteries. The internal carotid arteries pass into the cranium and give off the ophthalmic, posterior communicating and anterior choroidal arteries. The internal carotid arteries also form, by terminal bifurcation, the anterior and middle cerebral arteries.

[0065] Obstructions may form in any of the intracranial or extracranial cerebral arteries, including all of those described hereabove. Such obstructions may result from atherosclerotic narrowing of those arteries, or may come about due to a thromboembolic event, such as the migration of a blood clot into the cerebral circulation from the heart or some other location.

[0066] The clinical significance and severity of symptoms resulting from obstruction of the cerebral blood vessels may vary, depending on the origin or type of obstruction, the location of the obstruction and other factors. The degrees of resultant ischemia may vary, ranging from a) a “transient ischemic attack” (TIA) wherein a transient focal loss of neurologic function occurs, to b) a “partial non-progressing stroke” (PNS) producing minor persistent neurologic disability to c) a “completed stroke” (CS) producing major permanent neurologic disability.

[0067] The following are examples of applications wherein the ultrasound system 10aof the second embodiment of the present invention is utilized to treat obstructions of the cerebral blood vessels so as to treat or prevent conditions such as TIA, PNS or CS as described hereabove.

[0068] In this example, the second embodiment of the ultrasound system 10ashown in FIGS. 8-11 is utilized to treat an atherosclerotic obstruction of the extracranial internal carotid artery of a human being.

[0069] Initially, a guidewire 50 is percutaneously inserted into a peripheral artery and advanced, under radiologic guidance, to a position whereat the distal end of the guidewire 50 is positioned in the internal carotid artery immediately upstream of the. obstruction to be treated.

[0070] The proximal end of the guidewire is passed into the distal guidewire aperture 40cof the catheter device 16aand the catheter device 16ais advanced over the guidewire, with the proximal end of the guidewire 50 emerging from the sidewall guidewire aperture 41cas the catheter 16ais further advanced to a point where the distal head 30cof the catheter 16ais positioned adjacent the obstruction to be treated.

[0071] The guidewire 50 is then fully or partially withdrawn into the tubular guidewire lumen 51 of the catheter device 16a.

[0072] Foot pedal 11ais depressed to energize signal generator 12asuch that an electrical signal emitted by signal generator 12apasses through line 13ato ultrasound transducer 14a. Ultrasound from ultrasound transducer 14apasses, via proximal connector assembly 22a, into the proximal end of the ultrasound transmission member 20aand travels through ultrasound transmission member 20ato distal head member 40c, thereby causing ultrasonic vibration of distal head member 40c.

[0073] Concomitant with the delivery of ultrasound to the distal head member 40c, a flow of 0.9% Nacl solution is pumped via pump 28a, through the catheter lumen 26a. Such flow of saline solution through the catheter lumen 26aaccomplishes the dual function of a) bathing and cooling the ultrasound transmission member 20ato prevent excessive heat build-up as a result of the ultrasonic vibration thereof and b) providing a flow of irrigation/dilation fluid into central fluid passageway 32c, through secondary fluid passageway 42aand out of fluid outflow apertures 34a.

[0074] Also, concomitant with the delivery of ultrasound to the distal head 30cand the infusion of irrigation/dilation fluid out of fluid outflow apertures 34a, a suction is applied, via suction pump 62, through line 64 to aspiration sidearm 60, thereby drawing negative pressure on the lumen of aspiration tube 70 so as to draw particulate matter or other debris adjacent the distal tip of the catheter 16ainto the distal aspiration port 72, through aspiration tube 72 and into debris collection vessel 66.

[0075] The flow of saline solution out of the fluid outflow apertures 34aand the intake of matter into aspiration port 72 may be adjusted and controlled, by adjustment and control of infusion pump 28aand aspiration pump 62, such that the two(2) flow rates are substantially equal to one another, such that saline solution flowing out of the fluid outflow apertures 34awill circulate adjacent the distal head member and be subsequently withdrawn into the aspiration port 72aand through aspiration tube 70 into debris container 66. By such equilibration of the infusion outflow and aspiration outflow rate, a continuous fluid turnover may be affected to accomplish prompt lavage and removal of any particulate matter or other debris generated adjacent the distal head 30aof the catheter device 16a.

[0076] The catheter 16amay be proximally advanced and/or moved back and. forth so as to effectively treat the obstructive lesion, thereby improving blood flow and restoring patency to the lumen of the internal carotid artery wherein the treatment is applied.

[0077] When desired, the aspiration pump 62 may be turned off and a quantity of radiographic contrast medium may be passed into infusion sidearm 58, through catheter lumen 26aand out of distal fluid outflow apertures 34ato radiographically visualize the area of the obstruction for purposes of determining whether the treatment has effectively ablated or opened the obstruction.

[0078] After successful treatment and opening of the obstruction has been radiographically verified, the catheter device 16amay be withdrawn and removed.

[0079] In this example, the second embodiment of the ultrasound system 10ashown in FIGS. 8-11 is utilized to ultrasonically treat an obstruction of the intracranial middle cerebral artery of a human being.

[0080] Initially, a guidewire 50 is percutaneously inserted-into a peripheral artery and advanced, under radiographic guidance, to a position whereat the distal end of the guidewire 50 is positioned within the cerebral artery, immediately upflow of the obstruction to be treated.

[0081] Thereafter, the proximal end of the guidewire 50 is inserted into the guidewire entry aperture 40ain the distal head 30athe catheter device 16aand the catheter device 16ais advanced in the proximal direction, with the proximal end of the guidewire 50 emerging outwardly through sidewall guidewire aperture 41a. The advancement of the catheter 16ais continued until the distal head 30cis positioned in the middle cerebral artery immediately adjacent the obstruction to be treated.

[0082] Thereafter, the guidewire 50 is fully or partially withdrawn, at least to a point whereat the distal tip of the guidewire is within the guidewire tube 51 internal of the body of catheter 16a.

[0083] Foot pedal 11ais depressed to energize signal generator 12a, thereby'sending an electrical signal through line 13ato ultrasound transducer 14a. Ultrasound from transducer 14apasses, via proximal connector assembly 22a, into ultrasound transmission member 20aand is carried by said ultrasound transmission member 20ato the distal head 30aof the catheter device 16a, thereby causing the distal head 30ato vibrate ultrasonically within the desired frequency range.

[0084] Relaxation of the vascular smooth muscle within the middle cerebral artery results from the ultrasonic vibration within the above-stated frequency range, thereby causing some dilation of the middle cerebral artery in the region of the obstruction to be treated.

[0085] Concomitant with the delivery of ultrasound to the distal head member 30a, a flow of 0.9% NaCl solution is pumped via pump 28a, through the catheter lumen 26a. Such flow of saline solution through the catheter lumen 26aaccomplishes the dual function of a) bathing and cooling the ultrasound transmission member 20ato prevent excessive heat build-up as a result of the ultrasonic vibration thereof and b) providing a flow of irrigation/dilation fluid into central fluid passageway 32c, through secondary fluid passageway 42cand out of fluid outflow apertures 34c.

[0086] Also, concomitant with the delivery of ultrasound to the distal head 30aand the infusion of irrigation/dilation fluid out of fluid outflow apertures 34a, a suction is applied, via suction pump 62, through line 64 to aspiration sidearm 60, thereby drawing negative pressure on the lumen of aspiration tube 70aso as to draw particulate matter or other debris adjacent the distal tip of the catheter 16ainto the distal aspiration port 72athrough aspiration tube 72aand into debris collection vessel 66.

[0087] The flow of saline solution out of the fluid outflow apertures 34aand the intake of matter into aspiration port 72 may be adjusted and controlled, by adjustment and control of infusion pump 28aand aspiration pump 62, such that the two(2) flow rates are substantially equal to one another, such that saline solution flowing out of the fluid outflow apertures 34awill circulate adjacent the distal head member and be subsequently withdrawn into the aspiration port 72aand through aspiration tube 70ainto debris container 66. By such equilibration of the infusion outflow and aspiration outflow rate, a continuous fluid turnover may be affected to accomplish prompt lavage and removal of any particulate matter or other debris generated adjacent the distal head 30aof the catheter device 16a.

[0088] The catheter 16amay be proximally advanced and/or moved back and forth so as to effectively treat the obstructive lesion, thereby improving blood flow and restoring patency to the lumen of the internal carotid artery wherein the treatment is applied.

[0089] When desired, the aspiration pump 62 may be turned off and a quantity of radiographic contrast medium may be passed into infusion sidearm 58, through catheter lumen 26aand out of distal fluid outflow apertures 34ato radiographically visualize the area of the obstruction for purposes of determining whether the treatment has effectively ablated or opened the obstruction.

[0090] After successful treatment and opening of the obstruction has been radiographically verified, the catheter device 16amay be withdrawn and removed.

[0091] It will be appreciated that the foregoing drawings, descriptions of preferred embodiments, and examples serve to describe and illustrate specific embodiments of the invention but do not describe or encompass every possible embodiment of the invention which may be constructed or utilized. Accordingly, it is intended that the above-set-forth description., drawings and examples be broadly construed so as to encompass all foreseeable additions, modifications and alterations which those of skill in the art would be inclined to make.