(12) United States Patent
`Bagaoisan et al.
`
`USOO6849068B1
`US 6,849,068 B1
`Feb. 1, 2005
`
`(10) Patent No.:
`(45) Date of Patent:
`
`(54) ASPIRATION CATHETER
`(75) Inventors: Celso J. Bagaoisan, Union City, CA
`(US); Hung V. Ha, San Jose, CA (US);
`Mukund R. Patel, San Jose, CA (US);
`Sivette Lam, San Jose, CA (US)
`(73) Assignee: Medtronic AVE, Inc., Santa Rosa, CA
`(US)
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(*) Notice:
`
`(21) Appl. No.: 09/454,522
`(22) Filed:
`Dec. 6, 1999
`Related U.S. Application Data
`(63) Continuation of application No. 08/813,808, filed on Mar. 6,
`1997, now abandoned.
`(51) Int. Cl." ............................................... A61M 25/00
`(52) U.S. Cl. ........................................ 604/523; 604/540
`(58) Field of Search ................................. 604/523, 264,
`604/525,540, 96.01, 103.04; 600/585;
`606/191
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
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`FOREIGN PATENT DOCUMENTS
`
`EP
`WO
`WO
`WO
`WO
`
`1/1996
`O6932.95 A1
`6/1995
`WO95/15780
`5/1996 .......... A61M/29/00
`96/15824
`11/1997
`WO 97/44082
`10/1998
`WO 98/44982
`OTHER PUBLICATIONS
`“New Triple Coaxial Catheter System for Carotid Angio
`plasty with Cerebral Protection” Theron, et al., AJNR
`11:869–874 Sep./Oct. 1990.
`(List continued on next page.)
`Primary Examiner Brian L. Casler
`Assistant Examiner-Cris Rodriguez
`(74) Attorney, Agent, or Firm- Knobbe, Martens, Olson &
`Bear LLP
`ABSTRACT
`(57)
`Aspiration catheters Suitable for use in the treatment of an
`occlusion in a blood vessel are disclosed. These catheters are
`especially useful in the removal of occlusions from Saphe
`nous vein grafts, the coronary and carotid arteries, arteries
`above the aortic arch and even Smaller vessels. The catheters
`of the present invention are provided in either over-the-wire
`or in Single operator form. Radiopaque markers are prefer
`ably incorporated into distal ends of the catheters to facili
`tate their positioning within the body. The catheters are
`provided with varying flexibility along the length of the
`shaft, such that they are soft and flexible enough to be
`navigated through the vasculature of a patient without
`causing damage, but are Stiff enough to Sustain the axial
`push required to position the catheter properly and to Sustain
`the aspiration pressures.
`
`20 Claims, 6 Drawing Sheets
`
`6
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`-
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`6
`
`N
`
`1. af
`
`2
`
`aff
`
`2
`
`sa
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`Page 1
`
`
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`IPR2020-00126/-127/-128/-129/-130/-132/-134/-135/-136/-137/-138
`
`Medtronic Ex-1808
`Medtronic v. Teleflex
`
`

`

`US 6,849,068 B1
`Page 2
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`5,769,868 A
`6/1998 Yock .......................... 606/194
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`5,792,118 A * 8/1998 Kurth et al. ................ 604/246
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`5,827,229 A 10/1998 Auth et al. ................. 604/171
`5,279.546 A
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`5.830,196 A * 11/1998 Hicks ............
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`OTHER PUBLICATIONS
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`ANGIOJET LF 140 Rapid Thrombectomy Catheter Bro
`SE A : :
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`No. 98 907 741.7, dated Apr. 2, 2004.
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`PCT International Preliminary Examination Report received
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`9/1995 Ainsworth et al.
`in Application No. PCT/US 98/04494, dated Jun. 11, 1999.
`5,460,610 A 10/1995 Don Michael
`PCT International Search Report received in Application
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`No. PCT/US 98/04494, dated Mar. 6, 1998
`5,476,450 A 12/1995 Ruggio
`s
`•
`/s
`5,478.309 A 12/1995 Sweezer et al.
`* cited by examiner
`
`
`
`Page 2
`
`

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`U.S. Patent
`U.S. Patent
`
`Feb. 1, 2005
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`U.S. Patent
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`Feb. 1, 2005
`Feb. 1, 2005
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`US 6,849,068 B1
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`Feb. 1, 2005
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`Feb. 1, 2005
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`Feb. 1, 2005
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`1
`ASPRATION CATHETER
`
`US 6,849,068 B1
`
`This application is a continuation of application Ser. No.
`08/813,808, filed Mar. 6, 1997, now abandoned.
`
`BACKGROUND OF THE INVENTION
`
`25
`
`35
`
`40
`
`1. Field of the Invention
`The present invention relates to aspiration catheters for
`aspirating emboli, thrombi, and other types of particles from
`the vasculature of a patient, the apparatus being particularly
`well Suited for aspiration within Saphenous vein grafts,
`coronary arteries, and Similar vessels.
`2. Description of the Related Art
`15
`Human blood vessels often become occluded or com
`pletely blocked by plaque, thrombi, other deposits, emboli
`or other Substances, which reduce the blood carrying capac
`ity of the vessel. Should the blockage occur at a critical place
`in the circulatory System, Serious and permanent injury, or
`even death, can occur. To prevent this, Some form of medical
`intervention is usually performed when Significant occlusion
`is detected.
`Coronary heart disease is an extremely common disorder
`in developed countries, and is the leading cause of death in
`the U.S. Damage to or malfunction of the heart is caused by
`narrowing or blockage of the coronary arteries
`(atherosclerosis) that Supply blood to the heart. The coronary
`arteries are first narrowed and may eventually be completely
`blocked by plaque, and may further be complicated by the
`formation of thrombi (blood clots) on the roughened Sur
`faces of the plaques. Myocardial infarction can result from
`atherosclerosis, especially from an occlusive or near occlu
`Sive thrombi Overlying or adjacent to the atherosclerotic
`plaque, leading to death of portions of the heart muscle.
`Thrombi and emboli also often result from myocardial
`infarction, and these clots can block the coronary arteries, or
`can migrate further downstream, causing additional compli
`cations.
`Various types of intervention techniques have been devel
`oped which facilitate the reduction or removal of the block
`age in the blood vessel, allowing increased blood flow
`through the vessel. One technique for treating Stenosis or
`occlusion of a blood vessel is balloon angioplasty. A balloon
`catheter is inserted into the narrowed or blocked area, and
`the balloon is inflated to expand the constricted area. In
`many cases, near normal blood flow is restored. It can be
`difficult, however, to treat plaque deposits and thrombi in the
`coronary arteries, because the coronary arteries are Small,
`which makes accessing them with commonly used catheters
`difficult.
`Other types of intervention include atherectomy, deploy
`ment of Stents, introduction of Specific medication by
`infusion, and bypass Surgery. Each of these methods are not
`without the risk of embolism caused by the dislodgement of
`the blocking material which then moves downstream. In
`addition, the size of the blocked vessel may limit percuta
`neous access to the vessel.
`In coronary bypass Surgery, a more costly and invasive
`form of intervention, a Section of a vein, usually the Saphe
`nous vein taken from the leg, is used to form a connection
`between the aorta and the coronary artery distal to the
`obstruction. Over time, however, the Saphenous vein graft
`may itself become diseased, Stenosed, or occluded, similar
`to the bypassed vessel. Atherosclerotic plaque in Saphenous
`vein grafts tends to be more friable and less fibrocalcific than
`its counterpart in native coronary arteries.
`
`45
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`50
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`2
`Diffusely diseased old saphenous vein grafts with friable
`atherosclerotic lesions and thrombi have therefore been
`asSociated with iatrogenic distal embolic debris. Balloon
`dilatation of Saphenous vein grafts is more likely to produce
`Symptomatic embolization than dilatation of the coronary
`arteries, not only because of the difference in the plaque but
`also because vein grafts and their atheromatous plaques are
`generally larger than the coronary arteries to which they are
`anastomosed. Once the plaque and thrombi are dislodged
`from the vein, they can move downstream, completely
`blocking another portion of the coronary artery and causing
`myocardial infarction. In fact, coronary embolization as a
`complication of balloon angioplasty of Saphenous vein
`grafts is higher than that in balloon angioplasty of native
`coronary arteries. Therefore, balloon angioplasty of vein
`grafts is performed with the realization that involvement by
`friable atherosclerosis is likely and that atheroembolization
`represents a significant risk.
`Because of these complications and high recurrence rates,
`old diffusely diseased Saphenous vein grafts have been
`considered contraindications for angioplasty and
`atherectomy, Severely limiting the options for minimally
`invasive treatment. However, Some diffusely diseased or
`occluded Saphenous vein grafts may be associated with
`acute ischemic Syndromes, necessitating Some form of inter
`vention.
`There is therefore a need for improved methods of treat
`ment for occluded vessels Such as Saphenous vein grafts and
`the Smaller coronary arteries which decrease the risks to the
`patient.
`
`SUMMARY OF THE INVENTION
`The present invention provides novel aspiration catheters
`for removing plaque, thrombi, emboli, and other types of
`obstructions from blood vessels. The present invention
`advantageously Satisfies the need in the prior art by provid
`ing a catheter adapted to be compactly utilized in even the
`Smaller Size blood vessels. It can also be easily adapted to
`provide efficient and Speedy evacuation in larger size ves
`Sels. This System is compatible with more common therapy
`devices in widespread use today, and is designed for rapid
`evacuation and ease of use.
`The catheters of the present invention are provided in
`either over-the-wire or in Single operator form. The catheters
`are sized So as to be used in very Small blood vessels.
`Radiopaque markers are preferably incorporated into the
`distal ends of the catheters to facilitate their positioning
`within the body. The catheters are provided with varying
`flexibility along the length of the shaft, such that they are
`Soft and flexible enough to be navigated through the vascu
`lature of a patient without causing damage, but are Stiff
`enough to Sustain the axial push required to position the
`catheter properly and to Sustain the aspiration pressures.
`The catheters are preferably sized so as to allow the
`Slidable insertion of a therapy catheter through the main
`aspiration lumen of the aspiration catheter. Alternatively, the
`therapy catheter can be built over the aspiration catheter. In
`either case, the aspiration and therapy catheters can be
`delivered Simultaneously, Saving valuable time during the
`procedure.
`One embodiment of the aspiration catheter of the present
`invention therefore comprises an elongate flexible tubular
`body having a proximal end and a distal end. The catheter
`body or shaft incorporates a reinforcement Such as a metallic
`braid or coil or a polymer coil to provide Strength and
`flexibility to the device. A main lumen extends the length of
`
`Page 9
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`

`US 6,849,068 B1
`
`3
`the tubular body, and an aspiration port at the proximal end
`of the catheter body is in fluid communication with the main
`lumen, Such that aspiration pressure can be provided through
`the port and main lumen. The distal tip on the catheter is
`formed of a more flexible material than that used to form the
`rest of the catheter shaft.
`The reinforcement can be formed from a variety of
`materials, including polymers, Stainless Steel, Silver or gold
`plated Stainless Steel, ELGILOY, platinum, nitinol, or a
`combination thereof. The distal end of the catheter body is
`preferably more flexible than the proximal end, and this can
`be achieved by providing a braid or coil density at the distal
`end which is greater than the braid or coil density at the
`proximal end.
`The catheter's main lumen is preferably sized to receive
`at least one Separate catheter, Such as a therapy catheter,
`which is slidably disposed therein. The inner diameter of the
`main lumen is preferably about 0.045".
`The aspiration catheter of the present invention can
`include a Second lumen adjacent the main lumen which is
`adapted to receive a guidewire therethrough. The Second
`lumen can extend Substantially the entire length of the
`tubular body, or can extend less than 40 cm or less than 20
`cm in a proximal direction from the distal end of the body.
`The Second lumen can contain a Slit through a Side wall to
`allow insertion and removal of the guidewire therethrough.
`In a preferred embodiment, the Second lumen has an inner
`diameter of approximately 0.020" to receive a 0.014" diam
`eter guidewire.
`The distal tip of the catheter can have at least one side port
`to facilitate aspiration. The distal tip can be tapered, blunt,
`or angled to create an oblique opening. The catheter pref
`erably also comprises a valve in fluid communication with
`the main lumen, to control the application of aspiration
`preSSure at the distal end of the device. The aspiration
`catheter of the present invention can also incorporate various
`coatings, Such as hydrophilic or hydrophobic coatings, anti
`thrombogenic coatings, or a combination thereof.
`In another embodiment of the present invention, the
`aspiration catheter comprises an elongate flexible tubular
`body having a proximal end and a distal end, a main lumen
`extending through the tubular body sized to receive at least
`one separate catheter which is Slidably disposed therein, an
`aspiration port at the proximal end of the tubular body, the
`aspiration port being in fluid communication with the main
`lumen, and a tip on the distal end of the tubular body, the tip
`being formed of a more flexible material than that used to
`form the tubular body. Again, the catheter can have a Second
`lumen adjacent the first adapted to receive a guidewire
`therethrough, a specially shaped distal tip, and an optional
`Valve in fluid communication with the main lumen.
`In yet another embodiment of the present invention, the
`aspiration catheter comprises an elongate flexible tubular
`body having a proximal end and a distal end, a main
`aspiration lumen through the tubular body, an aspiration port
`on the proximal end of the tubular body in fluid communi
`cation with the main lumen, a therapeutic device attached to
`the distal end of the tubular body, and a tip on the distal end
`of the tubular body formed of a more flexible material than
`that used to form the tubular body itself. The therapeutic
`device can be an inflatable balloon and the catheter can
`include a separate inflation lumen for the balloon adjacent
`the main lumen.
`Accordingly, the catheters of the present invention pro
`vide for very fast and efficient aspiration of the working area
`Surrounding the occlusion in a blood vessel. The catheters
`
`4
`can be utilized in a wide range of vessel diameters, including
`extremely Small ones, are easy to use and can quickly and
`efficiently evacuate occlusions and debris, allowing the
`physician to restore normal blood flow in these vessels in a
`very short period of time.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a perspective View of a human heart showing a
`Saphenous vein graft used to bypass a portion of the coro
`nary arteries.
`FIG. 2 is a side view of an over-the-wire aspiration
`catheter in accordance with the present invention.
`FIG. 3 is a cross section of the aspiration catheter of FIG.
`2, taken along line 3-3 in FIG. 2.
`FIG. 4 is a cross section of the aspiration catheter of FIG.
`2 showing a guide wire over which the aspiration catheter
`rides.
`FIG. 5 is a side View of a single operator type aspiration
`catheter in accordance with the present invention.
`FIG. 6 is a cross section of the proximal end of the
`aspiration catheter of FIG. 5, taken along line 6-6 of FIG.
`5.
`FIG. 7A is a cross section of one embodiment of the distal
`end of the aspiration catheter of FIG. 5, taken along line
`7 7 of FIG. 5.
`FIG. 7B is a cross section of another embodiment of the
`distal end of the aspiration catheter of FIG. 5, also taken
`along line 7-7 of FIG. 5, showing a slit in the outer wall of
`the guidewire lumen through which the guidewire can be
`inserted and removed.
`FIGS. 8A-C are side views of the various embodiments
`of the distal end of the aspiration catheter of the present
`invention.
`FIG. 9 is a perspective view of an over-the-wire aspiration
`catheter and guidewire inserted into a Saphenous vein graft
`in accordance with the present invention, with the vein graft
`shown partially cut away.
`FIG. 10 is a schematic view of an occlusion catheter
`apparatus for use in the method of the present invention;
`FIG. 11 is a schematic cross-sectional view of a distal
`portion of the catheter apparatus shown in FIG. 10.
`FIG. 12 is a perspective view of a valve which can be
`positioned at the proximal end of the catheter of the present
`invention to control aspiration.
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`The present invention provides novel aspiration catheters
`for aspirating emboli, plaque, thrombi or other occlusions
`from a blood vessel and methods of using Same. The present
`invention is adapted for use in the treatment and removal of
`an occlusion in a blood vessel in which the occlusion has a
`length and a width or thickneSS which at least partially
`occludes the vessel's lumen. Thus, the catheters of the
`present invention are effective in treating both partial and
`complete occlusions of the blood vessels. AS used herein,
`“occlusion' includes both partial and complete occlusions,
`Stenosis, emboli, thrombi, plaque and any other Substance
`which at least partially occludes the vessel's lumen.
`The method of the present invention can be used to
`provide aspiration with or without the need for a Separate
`irrigation catheter and irrigation fluid. In the context of
`removing plaque, thrombi or other blockages from blood
`vessels. it has heretofore been proposed that an isolated
`
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`S
`“chamber Surrounding the occlusion be created prior to
`attempting treatment, and that Separate irrigation fluid be
`provided through an irrigation catheter to the chamber. It has
`been discovered that isolation of the occlusion is not
`required in Some cases, and that the occlusion can be
`Successfully removed through therapy and/or aspirating of
`the resulting debris without the need for delivery of a
`Separate irrigation catheter and irrigation fluid in those
`vessels where certain pressure and fluid flow conditions
`exist, Such as Saphenous vein grafts, coronary arteries,
`carotid arteries and Similar vessels.
`In non-bifurcated areas of the blood vessels, it has been
`discovered that fluid from the proximal portion of the same
`vessel acts as an infusion Source. One can therefore occlude
`only the distal portion of the vessel to create a working area
`surrounding the occlusion and allow blood to flow from the
`proximal portion of the vessel into the working area. The
`working area Surrounding the occlusion is aspirated through
`the guiding catheter or aspiration catheter. It should be noted
`that, as used herein, “proximal' refers to the portion of the
`apparatus closest to the end which remains outside the
`patient's body, and “distal” refers to the portion closest to
`the end inserted into the patient’s body.
`The method and apparatus of the present invention can be
`used in any vessel of the body where the pressure is at least
`0.2 psi, and preferably, is about 1.2 psi, with a flow rate of
`at least 10 cc per minute. The method and apparatus are
`particularly Suited for use in removal of occlusions from
`Saphenous vein grafts, coronary and carotid arteries, and in
`other non-branching vessels having similar pressures and
`flow where a Suitable working area can be created. A
`Saphenous vein graft is depicted in FIG. 1. The graft 2 is
`used to bypass one of the occluded coronary arteries 4, and
`connects the aorta 6 to the coronary artery at a location distal
`the occlusion 8. Although the present invention will be
`described in connection with a Saphenous vein graft, it
`should be understood that this application is merely
`exemplary, and the method can be used in other blood
`vessels as well.
`Apparatus Used with the Present Invention
`1. Guide Catheter and Occlusion Catheter
`To perform the method of the present invention, a guide
`catheter having a single lumen is first introduced into the
`patient's vasculature through an incision made in the femo
`ral artery in the groin and used to guide the insertion of other
`catheters and devices to the desired Site. Following insertion
`of the guide catheter, a Second catheter is inserted through
`the guide catheter and past the Site of the occlusion. The
`catheter has an occlusive device, Such as an inflatable
`balloon, filter or other mechanical occlusive device, attached
`at its distal end. The occlusive device should be capable of
`preventing the migration of particles and debris from the
`working area, either through total or partial occlusion of the
`vessel. Note that the occlusion of the vessel need not be
`complete. Substantial occlusion of the vessel can be Suffi
`cient for purposes of the present invention. The catheter
`should be sized so as to be slidable with respect to the
`therapy and aspiration catheters inserted over the catheter.
`The catheter is preferably made of metal Such as StainleSS
`Steel or nitinol, plastics, or composites. A guidewire having
`an occlusive device on its distal end is also Suitable for use
`in the present method. The method of the present invention
`can be effectively carried out using a number of guidewires
`or catheters that perform the function of occluding the vessel
`and allowing for the slidable insertion of various other
`catheters and devices. The term “catheter' as used herein is
`therefore intended to include both guidewires and catheters
`with these desired characteristics.
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`A catheter Suitable for use in the present invention is
`illustrated in FIGS. 10 and 11. The catheter apparatus 110 is
`generally comprised of four communicating members
`including an elongated tubular member 114, an inflatable
`balloon member 116, a core-wire member 120 and a coil
`member 122. The catheter apparatus 110 is preferably pro
`Vided with an outer coating of a lubricous material, Such as
`Teflon.
`The body member 114 of the catheter apparatus 110 is in
`the form of hypotubing and is provided with proximal and
`distal ends 114A and 114B as well as an inner lumen 115
`extending along the tubular member 114. The balloon mem
`ber 116 is coaxially mounted on the distal end 114B of the
`tubular member 114 by suitable adhesives 119 at a proximal
`end 116A and a distal end 116B of the balloon member 116
`as in the manner shown in FIG. 11. Ther core-wire member
`120 of the catheter 110 may be comprised of a flexible wire
`120. The flexible wire 120 is joined by soldering, crimping
`or brazing at a proximal end 120A of the flexible wire 120
`to the distal end 114B of the tubular member 114 as in the
`manner show in FIG. 11.
`The proximal end 120A of the flexible wire 120 can have
`a transverse croSS Sectional area Substantially less than the
`Smallest transverse croSS-Sectional area of the inner lumen
`115 of the tubular member 114. The flexible wire 120 can
`also taper in the distal end 120B to smaller diameters to
`provide greater flexibility to the flexible wire 120. However,
`the flexible wire may be in the form of a solid rod, ribbon
`or a helical coil or wire or combinations thereof.
`As shown in FIG. 11, the distal end 120B of the flexible
`wire 120 is secured to a rounded plug 118 of solder or braze
`at the distal end 122B of the coil member 122. The coil
`member 122 of the catheter 110 may be comprised of a
`helical coil 122. The coil member 122 is coaxially disposed
`about the flexible wire 120, and is secured to the flexible
`wire 120 by soldering or brazing at about the proximal end
`120A of the flexible wire 120 as in the mannershown in FIG.
`11.
`The balloon member 116 is preferably a compliant bal
`loon formed of a Suitable elastic material Such as a latex or
`the like. The flexible coil 122 is preferably formed of a wire
`of platinum or gold based alloys. The flexible core-wire 120
`and the tubular member 114 are preferably formed of a
`Superelastic nickel-titanium alloy.
`The catheters of the present invention are preferably
`provided with a coating on the outer Surface, or on both the
`inner and outer Surfaces. Suitable coatings include
`hydrophilic, hydrophobic and antithrombogenic coatings.
`Examples include heparin and TEFLON. These coatings can
`be applied using methods well known in the art.
`Additional details relative to the catheters described
`above are found in copending applications Ser. Nos. 08/813,
`023 and 08/812,876, filed Mar. 6, 1997, entitled “Catheter
`for Emboli Containment' and "Hollow Medical Wires and
`Methods of Constructing Same,” and U.S. Pat. No. 5,868,
`705, all of which are hereby incorporated by reference in
`their entirety.
`2. Therapy Catheter
`Once the guiding catheter and Second catheter have been
`properly positioned inside the vessel, the occlusive device at
`the distal end of the catheter is actuated to occlude the vessel
`distal to the existing occlusion to create a working area. A
`therapy catheter then is delivered to the Site of the occlusion.
`The term “therapy catheter' is meant to include any of a
`number of known devices used to treat an occluded vessel.
`For example, a catheter carrying an inflatable balloon for use
`in balloon angioplasty can be delivered to dilate the occlu
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`Sion. Thermal balloon angioplasty includes the use of heat to
`"mold' the vessel to the Size and shape of the angioplasty
`balloon. Similarly, an intravascular Stent can be delivered
`via a balloon catheter and deployed at the Site of the
`occlusion to keep the vessel open. Cutting, Shaving, Scraping
`or pulverizing devices can be delivered to excise the occlu
`Sion in a procedure known as atherectomy. A laser or
`ultrasound device can also be delivered and used to ablate
`plaque in the vessel. Various thrombolytic or other types of
`drugs can be delivered locally in high concentrations to the
`Site of the occlusion. It is also possible to deliver various
`chemical Substances or enzymes via a catheter to the Site of
`the stenosis to dissolve the obstruction. The term “therapy
`catheter' encompasses these and Similar devices.
`3. Aspiration Catheter
`After the therapy has been performed and the Stenosis has
`been removed or reduced using any of the methods and
`apparatus described above, the working area is aspirated to
`remove fluid and debris. Aspiration pressure can be provided
`through the guide catheter if desired. A Source of negative
`preSSure is attached at the proximal end of the guide catheter
`to create reverse flow, and fluid and debris are aspirated
`through the guide catheter's main lumen.
`Alternatively, an aspiration catheter or Similar debris
`removing device is delivered to the working area to remove
`particles and any other debris. The term "aspiration catheter'
`includes any device which creates an area of fluid turbulence
`and uses negative pressure and reverse flow to aspirate fluid
`and debris, and includes those devices which create a venturi
`effect within the vessel. should be noted that any particles
`which break free during therapy and aspiration procedures
`will be kept at the site of the procedure within the working
`area by the occlusive device occluding the distal portion of
`the vessel in combination with the blood preSSure coming
`from the proximal portion of the vessel. The debris is
`prevented from migrating elsewhere, and remains localized
`for removal by aspiration.
`An aspiration catheter particularly Suited for use in the
`treatment and removal of occlusions in blood vessels is
`illustrated in FIG. 2. The catheter 10 includes an adaptor 14,
`preferably a female luer adaptor, and a Seal 16 at its proximal
`end. The catheter 10 further includes an aspiration port 18 to
`which a Source of negative pressure is attached. The aspi
`ration catheter further comprises a long tubular body 20
`having a distal end 22. The distal tip 22 can include a
`radiopaque marker to aid in locating the tip 22 during
`insertion into the patient, and is preferably Soft to prevent
`damage to the patient's vasculature. The aspiration catheter
`is preferably about 145 cm in length, although this length
`can be varied as desired.
`The aspiration catheter illustrated in FIG. 2 is an over
`the-wire catheter. As seen in FIG. 3