`(12) Patent Application Publication (10) Pub. No.: US 2005/0015073 A1
`Kataishi et al.
`(43) Pub. Date:
`Jan. 20, 2005
`
`US 2005OO15073A1
`
`(54) THROMBUS SUCTION CATHETER WITH
`IMPROVED SUCTION AND CROSSING
`(76) Inventors: Yuichi Kataishi, Yokohama-shi (JP);
`Satoru Mori, Osaka-shi (JP);
`Yoshihiko Sano, Osaka-shi (JP);
`Toshihiro Kikuchi, Osaka-shi (JP);
`Takaaki Isshiki, Tokyo (JP)
`Correspondence Address:
`KUBOVCK & KUBOVCK
`SUTE 710
`900 17TH STREET NW
`WASHINGTON, DC 20006
`
`(21) Appl. No.:
`(22) Filed:
`
`10/761,806
`Jan. 22, 2004
`
`Foreign Application Priority Data
`(30)
`Jan. 22, 2003 (JP)...................................... 2003-013952
`
`Publication Classification
`(51) Int. Cl." .............................................. A61M 25/01
`(52) U.S. Cl. .............................................................. 604/528
`(57)
`ABSTRACT
`
`A thrombus Suction catheter which is a tube having a distal
`end opening formed by an angled cut Surface. In the distal
`end opening, at least a part on the proximal end Side of the
`cut Surface is formed in a concave shape in an angled
`direction, and the distal end Side of the cut Surface is formed
`to be flat and flexible. With the distal end configuration,
`Suction and crossing are significantly improved.
`
`
`
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`THROMBUS SUCTION CATHETER WITH
`IMPROVED SUCTION AND CROSSING
`
`FIELD OF THE INVENTION
`0001. The present invention relates to a thrombus suction
`catheter for removing a thrombus from coronary arteries,
`which is capable of removing atheroma by Suction and has
`remarkably improved Suction and crossing (reaching ability
`and Smooth passage to a Subject site).
`
`BACKGROUND OF THE INVENTION
`0002 Acute myocardial infarction is a disease in which
`the blood vessel (coronary artery) for Supplying oxygen and
`nutrients to the heart itself is clogged with a formed throm
`bus, and blood flow is blocked decreasing the function of the
`heart. About 40,000 people per year receive treatment for
`this disease in Japan. Heart disease is the first leading cause
`of death in Europe and the United States, and is the second
`leading cause of death following malignant neoplasma (can
`cer) in Japan, and is on the rise recently due to factors Such
`as westernization of dietary culture and an increase in StreSS
`in Social life. In recent years, treatment involving reopening
`of a clogged portion to allow the blood to be reperfused has
`been conducted, whereby the death rate in hospitals has
`become 10% or leSS. In general, as a reperfusion treatment,
`there are a method of injecting a drug for dissolving a
`thrombus and a method of expanding a blood vessel nar
`rowed with a thrombus using a PTCAballoon catheter or the
`like.
`0003. It is considered that the cause of a thrombus inside
`the coronary arteries is as follows: a gap is formed between
`cells of an inner membrane (vascular endothelium) consti
`tuting the blood vessel due to StreSS, westernization of diet,
`Smoking, drinking, etc.; and a low-density lipoprotein
`(LDL) is infiltrated through the gap. The infiltrated LDL is
`oxidized to become oxidized LDL. The body attempts to
`treat the oxidized LDL, which is a foreign matter, and
`macrophages gather, whereby endocytosis Starts. As a result,
`a gruel-like Substance called lipid core is accumulated
`between the vascular endothelium and the vascular tunica
`media and is expanded in a dome shape inside the blood
`vessel to formatheroma (see FIG. 10). When the lipid core
`is accumulated exceeding a certain acceptable range, the
`vascular endothelium in the atheroma portion ruptures. At
`this time, blood platelets in the blood attempt to repair the
`rupture portion forming a thrombus. When the thrombus is
`formed, blood flow in the coronary arteries is blocked. As a
`result, oxygen and nutrients are not Supplied to the heart
`itself, whereby the function of the heart is lost. If the
`thrombus thus formed is not removed early for reperfusion,
`death can result.
`0004 Thrombus suction therapy is a therapeutic method
`of inserting a tubule with a diameter of about 1.5 mm
`(referred to as a catheter) through a leg or arm to allow the
`catheter to reach a lesion portion in the coronary arteries,
`and removing a thrombus itself by Suction. According to the
`thrombus Suction therapy, a thrombus causing the blood
`vessel to be narrowed is itself removed. Therefore, risks
`involved in conventional methods Such as renarrowing of
`coronary arteries due to a thrombus that is not completely
`dissolved by a drug and damage caused by exceSS expansion
`of a blood vessel, can be avoided.
`
`0005 The above-mentioned catheter for removing a
`thrombus from inside the coronary arteries is called a
`thrombus Suction catheter, which is used in combination
`with a Suction device. The Suction device conventionally
`includes two kinds: (1) a vacuum pump using a driving force
`Such as electricity, and (2) a Syringe. With the vacuum pump,
`there is a limit to the ability of a pump and a negative
`preSSure maintenance mechanism using a check valve. Up to
`now, the proximal end of a catheter can produce only 640
`mmHg of negative pressure.
`0006 Also, a certain degree of strength is required in a
`catheter So that the wall Surface of the catheter is not crushed
`due to the negative pressure. Furthermore, in order to
`facilitate a discharge of an aspirated Substance from a lesion
`portion to the outside of a body, it is necessary to maximize
`the area (opening area) of an opening cross-section. In a
`conventional catheter, the opening area remains about 0.65
`mm, and the wall thickness for maintaining the strength is
`0.15 mm or more. However, if the wall thickness is
`increased So as to avoid crushing, flexibility of the catheter
`is impaired. Therefore, in the case where a lesion portion is
`at a position that is sharply curved (e.g., #3, #4 of the
`coronary arteries), crossing of the catheter is unsatisfactory,
`making it impossible to allow the catheter to reach the lesion
`portion.
`0007. The shape of a distal end opening of a catheter is
`also important for the thrombus Suction catheter.
`0008. The opening of a conventional thrombus suction
`catheter is angled about 30 to 45 with respect to a
`longitudinal axis. However, in the case where the vascular
`endothelium is expanded in a dome shape due to lipid core
`as described above, when the distal end of the catheter is cut
`Straight, the Surface of a lesion portion cannot be completely
`covered even if a cut Surface is angled with respect to the
`longitudinal axis of the catheter. Thus, a gap is formed
`between the expanded lesion portion and the catheter. AS a
`result, the blood flows into the catheter from the distal end
`of the catheter during Suction, and the negative preSSure
`produced by a Suction tool cannot be completely transmitted
`to the lesion portion, i.e., a thrombus or the vascular endot
`helium of the lesion portion. Thus, Sufficient Suction cannot
`be obtained.
`0009. The present invention has been made in view of the
`above, and its object is to provide a thrombus Suction
`catheter with improved Suction and crossing, capable of
`aspirating atheroma and reaching even a lesion portion that
`is sharply bent.
`
`SUMMARY OF THE INVENTION
`0010. In order to attain the above-mentioned object, the
`inventors of the present invention Studied earnestly. AS a
`result, the following has been found: by forming a distal end
`opening So that at least a part of the proximal end Side of the
`opening is concave and the distal end Side flat, crossing is
`improved, a lesion portion expanded at the distal end open
`ing can be covered, and Suction is remarkably improved,
`thereby achieving the present invention. That is, according
`to the present invention, there is provided a thrombus
`Suction catheter with improved Suction and crossing having
`a Small pressure loSS, which is a tube having a lumen passing
`through from a proximal end to a distal end, a distal end
`opening having an angled cut Surface, in which at least a part
`
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`on the proximal end Side of the angled Surface is formed in
`a concave shape in the angled direction and the distal end
`side of the cut Surface is formed to be flat and flexible and
`is terminated in a necked-down tip.
`0.011
`Here, the distal end of the distal end opening can be
`eccentric to the longitudinal axis. Further, it is preferable
`that the pressure loSS at the Start of Suction in the distal end
`opening of the catheter is 90% or less. It is preferable that
`the catheter is reinforced with a reinforcing wire. It is
`preferable that a guide wire insertion port is provided at a
`position 25 to 35 cm from the distal end of the distal end
`opening on the same side of the catheter as the reinforcing
`wire. Further, a marker for identifying an insertion position
`may be provided in a vicinity of the distal end opening.
`0012. The thrombus suction catheter of the present inven
`tion provides a further effect by combining with a Suction
`pump. That is, the invention also relates to a thrombus
`Suction System including Suction pump and the thrombus
`Suction catheter, in which Suction pressure at the proximal
`end of the thrombus Suction catheter is variable, and the
`Suction is obtained continuously. Here, a Suction pump
`which can produce a Suction pressure of 650 mmHg or
`higher at the proximal end of the thrombus Suction catheter,
`is preferable.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`0013 FIG. 1 is a front view of a thrombus suction
`catheter showing an example of the present invention.
`0.014
`FIG. 2 is a cross-sectional view showing an
`enlarged main portion of FIG. 1.
`0.015
`FIG. 3 is a plan view showing the enlarged main
`portion of FIG. 1.
`0016 FIG. 4 is an enlarged cross-sectional view taken
`along line A-A shown in FIG. 1.
`0017 FIG. 5 is an enlarged cross-sectional view taken
`along line B-B shown in FIG. 1.
`0.018
`FIG. 6 a view illustrating the vicinity of a guide
`wire insertion port of the thrombus Suction catheter shown
`in FIG. 1.
`0019 FIG. 7 is a view illustrating a thrombus suction
`System of the present invention.
`FIG. 8 is a view illustrating a crossing test.
`0020
`0021
`FIG. 9 is a view illustrating a suction pressure
`comparison test.
`0022 FIG. 10 is view showing a state where the throm
`buS Suction catheter of the present invention covers an
`atheroma.
`0023 FIG. 11 is a view showing a conventional example
`of a thrombus Suction catheter.
`0024 FIG. 12 is a perspective view of the cathter of the
`present invention.
`
`THE MOST PREFERRED EMBODIMENTS OF
`THE INVENTION
`Next, the present invention will be described by
`0.025
`way of examples with reference to the drawings.
`
`0026. As illustrated in FIGS. 1 and 12, a thrombus
`Suction catheter of the present invention is a tube having a
`distal end opening 12 formed by an angled cut Surface. In the
`distal end opening 12, at least a part 161 on the proximal end
`Side of the cut Surface 16 is formed in a concave shape in the
`angled direction, and the distal end Side 162 of the cut
`Surface 16 is formed to be flat and flexible and to neck down
`at its tip. With this distal end configuration, Suction and
`crossing are significantly improved.
`0027. As shown in FIGS. 1, 4, 5 and 12, a preferred
`embodiment of the thrombus Suction catheter includes a
`catheter body 1, a connector 2 provided at a proximal end of
`the catheter body 1, and a reinforcement wire 3 embedded
`in a reinforcement wire lumen 17 of the catheter body 1. The
`catheter body 1 is a tube formed of a flexible plastic such as
`polyamide elastomer, polyurethane, polyester elastomer, and
`polyethylene. The catheter body 1 has a lumen 11 passing
`through from the proximal end to a distal end, and a distal
`end opening 12 is provided as a thrombus Suction port at the
`distal end. As shown in FIGS. 2 and 3, the distal end
`opening 12 is provided with a cut Surface 16 having on its
`proximal end Side a first cut Surface 163 defining an angle
`with the longitudinal axis of the catheter, a rearwardly
`extending (in the proximal direction) ledge Surface 164
`parallel to the longitudinal axis of the catheter and a Second
`concave cut Surface 161 beginning at the trailing end of the
`ledge Surface 164 and also angled with respect to the
`longitudinal axis. The cut Surface 161 is formed in a concave
`shape (including the shape of an asymptote) in the angled
`direction as shown in FIG. 2. The concave portion 161 is a
`means for improving flexibility of the catheter distal end and
`enabling the cut Surface 16 to adsorb an expanded atheroma
`AT by Suction, when the atheroma AT as shown in FIG. 10
`is covered with the distal end opening 12 and is aspirated
`with a suction pump (6 in FIG. 7). This remarkably
`enhances Suction (the Suction pressure becomes Substan
`tially equal to actual pump preSSure when the cut Surface 16
`completely adsorbs the atheroma AT), and enables Suction of
`the lipid core (LC) in a vascular endothelium (ET). Thus, the
`concave cut Surface or portion 161 may have any shape, as
`long as it is angled in an angled direction, i.e., a proximal
`direction. Generally, the concave cut portion 161 is formed
`So as to be gently concave So that atheroma can be covered
`and the gap minimized. The concave cut portion 161 is
`provided at least partially on the proximal end Side of the cut
`surface 16. More specifically, the concave portion 161 may
`be provided entirely on the proximal end side of the cut
`Surface 16 (i.e., without cut Surface 163 and ledge Surface
`164) or partially on the proximal end side (as shown, for
`example, in FIG. 2), considering the shape of atheroma.
`0028. The flat portion 162 on the distal end side of the cut
`Surface 16 is a means for enhancing the crossing as well as
`the flexibility of a catheter distal end and includes a lumen
`15 for a guide wire.
`0029. The lumen 11 is a path for a thrombus aspirated
`from the distal end opening 12, and the thrombus is collected
`in a thrombus collection bottle (5 in FIG. 7) through the
`lumen 11. The distal end side of the thrombus Suction
`catheter is provided with guide wire lumen 15 that is opened
`at the distal end of the catheter. Generally, a guide wire
`insertion port 13 is provided at a position of 2 to 50 cm from
`the distal end, preferably 25 to 35 cm from the distal end.
`Furthermore, the thrombus suction catheter is provided with
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`a reinforcement wire lumen 17 so as to improve the ability
`(referred to as “pushability”) of transmitting a force propel
`ling the catheter to the distal end. A reinforcement wire 3
`formed of, for example, Stainless Steel is embedded in the
`reinforcement wire lumen 17. The reinforcement wire lumen
`17 extends from the proximal end of the catheter body 1 to
`a position of about 10 to 11 cm on the distal end side, beyond
`the position of the guide wire insertion port 13, and is shifted
`at the position of the guide wire insertion port 13 with a
`diameter thereof being narrowed (see FIGS. 4, 5, and 6).
`The reinforcement wire 3 has its distal end side tapered from
`the guide wire insertion port 13 in accordance with the
`diameter of the reinforcement wire lumen 17.
`0.030. In the thrombus suction catheter of the present
`invention, it is preferable to provide a marker (contrast
`marker) 14 for identifying the insertion position of the
`catheter in the catheter body1 in the vicinity of the distal end
`opening 12. The contrast marker 14 can be attached to the
`catheter body 1, for example, by caulking and wrapping a
`ring of platiniridium around the contrast marker 14.
`0031. In the thrombus suction catheter of the present
`invention, the outer wall of the catheter and the tube wall
`areas required for forming the guide wire lumen 15 and the
`reinforcement wire lumen 17 are minimized (however, the
`thrombus Suction catheter is reinforced with the reinforce
`ment wire 3). Therefore, the cross-sectional area of the
`lumen 11 is large, and pressure loSS is Small as will be
`understood from Table 1 described later.
`0032
`Crossing Test
`0033. An artificial blood vessel model and a guiding
`catheter (produced by Terumo Corporation, 7Fr JR4: inner
`diameter 0.075") lightly attached to the model as shown in
`FIG. 8 were prepared. The artificial blood vessel model
`(wave type with a length of 200 mm, an inner diameter of
`3 mm, and a cycle of 20 mm) was immersed in hot water at
`37° C., and a guide wire (produced by ACS, HI-TORQUE
`BALANCE MIDDLEWEIGHT, 0.014") was inserted into
`the model. After that, the thrombus Suction catheter was
`moved forward along the guide wire, and an insertion length
`of the catheter when the artificial blood vessel model was
`Separated from the guiding catheter was recorded. A throm
`bus suction catheter (N=10) of the present invention reached
`a position B (insertion length: 17 cm), whereas a commer
`cially available thrombus suction catheter (N=2, produced
`by S company, a distal end thereof is diagonally cut in a
`Straight line) only reached a position A (insertion length: 9
`cm). The thrombus Suction catheter of the example had an
`outer diameter of 4.5 Fr (corresponding to an outer diameter
`of 1.43 mm), and a lumen cross-sectional area of 0.90 mm
`on the proximal end side and 0.80 mm on the distal end side
`from the guide wire insertion port. The thrombus Suction
`catheter of the comparative example had an outer diameter
`of 4.5 Fr, and a lumen cross-sectional area of 0.65 mm.
`0034. As a result, it is understood that crossing of the
`thrombus Suction catheter of the present invention was
`remarkably improved, compared with that of the commer
`cially available thrombus Suction catheter.
`0035) Suction Pressure Comparison Test
`0.036 Water was added to glycerin to obtain a preparatory
`liquid 5 with Substantially the same viscosity as that of
`blood. As shown in FIG. 9, a thrombus Suction catheter
`
`(Example, N=10) of the present invention similar to that
`used in the crossing test and the above-mentioned commer
`cially available catheter (Comparative Example, N=5) were
`used. The catheters were respectively inserted into elongated
`tubes with an outer diameter of 2.5 mm, and immersed in the
`preparatory liquid. The Suction pressure was measured with
`a varying preSSure of a pump and a varying distance from a
`preSSure gauge. The results as shown in Table 1 were
`obtained. The Sealing position in a Suction pressure mea
`Surement System was set to be the position of a hydrophobic
`filter.
`0037. It is understood from the table that the Suction force
`of the catheter of the present invention is about twice that of
`the commercially available thrombus Suction catheter, and
`the preSSure loSS at the Start of Suction at the distal end
`opening is 90% or less.
`
`TABLE 1.
`
`Set
`pressure
`
`Actual pump
`pressure
`
`Suction pressure
`
`(mm Hg)
`6OO
`640
`68O
`700
`6OO
`
`(mmHg) () mm:1 60 mm2 100 mm 3
`596
`63
`60
`58.5
`637
`69
`69
`61.5
`679
`81
`75
`72
`699
`79.5
`76.5
`81
`596
`36
`34.5
`34.5
`
`640
`
`68O
`
`700
`
`637
`
`679
`
`699
`
`37.5
`
`39
`
`42
`
`37.5
`
`37.5
`
`39
`
`33
`
`3O
`
`3O
`
`Example 1
`Example 2
`Example 3
`Example 4
`Comparative
`Example 1
`Comparative
`Example 2
`Comparative
`Example 3
`Comparative
`Example 4
`
`*1, 2, 3: distance between the thrombus suction catheter and the con
`necting portion to the tube of the pressure gauge.
`0038 Next, a thrombus suction system of the present
`invention will be described.
`0039 The thrombus suction system includes the throm
`buS Suction catheter of the present invention and a Suction
`pump 6, as shown in FIG. 7, and is generally combined with
`an extension tube 4 and a thrombus collection bottle 5. The
`extension tube 4 is provided with a clamp 41, and the clamp
`41 is closed before and after the thrombus Suction. When the
`clamp 41 is opened to drive the Suction pump 6, the Suction
`of a thrombus is started. The thrombus aspirated from the
`distal end opening 12 is collected in the thrombus collection
`bottle 5 through the catheter body 1 and the extension tube
`4.
`0040. As the Suction pump 6 useful in the present inven
`tion, those which can produce a Suction pressure of 650
`mmHg or higher at the proximal end (proximal end of the
`connector 2) of the thrombus Suction catheter can be used.
`0041 According to the present invention, the suction
`pump 6 is used as Suction means. Therefore, the Suction
`preSSure at the proximal end of the thrombus Suction cath
`eter can be varied arbitrarily in accordance with a lesion.
`Furthermore, the Suction preSSure can be obtained continu
`ously, So that treatment can be performed in a short period
`of time.
`
`INDUSTRIAL APPLICABILITY
`0042 AS is apparent from the above description, the
`thrombus Suction catheter of the present invention has a
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`crossing that enables the catheter to reach even a lesion
`portion sharply bent. Therefore, the catheter can reach even
`a portion Sharply curved, Such as #3 and #4 of the coronary
`arteries, which were impossible to reach conventionally.
`Furthermore, the thrombus suction catheter of the present
`invention has a large cross-sectional area of a lumen and has
`Strength of Such magnitude that the catheter withstands a
`Suction force of 650 mmHg or higher. Therefore, the throm
`buS Suction catheter of the present invention has a large
`Suction force at the distal end opening and is excellent in
`thrombus removal ability. Still furthermore, the distal end
`opening is of a shape Such that the opening is likely to adsorb
`a atheroma during Suction. Therefore, a large Suction force
`can be obtained, and atheroma can be aspirated.
`1. A thrombus Suction catheter comprising a tube having
`a first lumen passing through from a proximal end to a distal
`end of the catheter,
`an opening at the distal end of the catheter,
`an insertion port for a guidewire provided in the catheter
`at a position apart from the distal end of the catheter,
`a Second lumen provided for the guidewire and extending
`from the insertion port to the opening at the distal end
`of the catheter,
`wherein the opening at the distal end of the catheter
`comprises a cut Surface angled with respect to the axis
`of the catheter, the cut Surface terminating in a necked
`down tip at a distal side of the cut Surface, and at least
`a portion of the cut Surface on a proximal Side of the cut
`Surface being concave in the angled direction, and the
`necked-down tip including the Second lumen provided
`for the guidewire.
`2. The thrombus Suction catheter according to claim 1,
`wherein the cut Surface on a proximal Side of the cut Surface
`includes a first cut Surface angled in the proximal direction
`of the catheter, a ledge Surface which is Substantially parallel
`to the longitudinal axis of the catheter and extends from the
`first cut Surface in the proximal direction and a Second
`concave cut Surface extending from the ledge Surface and
`angled in the proximal direction of the catheter.
`3. The thrombus Suction catheter according to claim 1,
`wherein the the necked-down tip is eccentric to the longi
`tudinal axis of the catheter.
`4. The thrombus Suction catheter according to claim 2,
`wherein the the necked-down tip is eccentric to the longi
`tudinal axis of the catheter.
`5. The thrombus Suction catheter according to claim 1,
`wherein the opening at the distal end of the catheter provides
`a pressure loss at a start of suction of 90% or less.
`6. The thrombus Suction catheter according to claim 2,
`wherein the opening at the distal end of the catheter provides
`a pressure loss at a start of suction of 90% or less.
`7. The thrombus Suction catheter according to claim 21,
`further comprising a reinforcing wire in Said third lumen.
`
`8-10. (canceled)
`11. The thrombus Suction catheter according to claim 1,
`wherein the insertion port for the guide wire is provided at
`a position 25 to 35 cm from the distal end of the opening at
`the distal end of the catheter.
`12. The thrombus Suction catheter according to claim 2,
`wherein the insertion port for the guide wire is provided at
`a position 25 to 35 cm from the distal end of the opening at
`the distal end of the catheter.
`13. The thrombus suction catheter according to claim 3,
`wherein the insertion port for the guide wire is provided at
`a position 25 to 35 cm from the distal end of the opening at
`the distal end of the catheter.
`14. The thrombus Suction catheter according to claim 4,
`wherein the insertion port for the guide wire is provided at
`a position 25 to 35 cm from the distal end of the opening at
`the distal end of the catheter.
`15. The thrombus Suction catheter according to claim 1,
`wherein a marker for identifying a position of the catheter is
`provided in a vicinity of the distal end opening.
`16. The thrombus Suction catheter according to claim 2,
`wherein a marker for identifying a position of the catheter is
`provided in a vicinity of the distal end opening.
`17. A thrombus Suction System comprising a Suction
`pump and the thrombus Suction catheter of claim 1, wherein
`the Suction pump provides a variable and continuous pres
`Sure at the proximal end of the thrombus Suction catheter.
`18. A thrombus Suction system comprising a Suction
`pump and the thrombus Suction catheter of claim 2, wherein
`the Suction pump provides a variable and continuous pres
`Sure at the proximal end of the thrombus Suction catheter.
`19. The thrombus suction system according to claim 17,
`wherein the Suction pump is capable of producing a Suction
`pressure of 650 mmHg or higher at the proximal end of the
`thrombus Suction catheter.
`20. The thrombus suction system according to claim 18,
`wherein the Suction pump is capable of producing a Suction
`pressure of 650 mmHg or higher at the proximal end of the
`thrombus Suction catheter.
`21. A thrombus Suction catheter according to claim 1,
`further comprising a third lumen provided for a reinforcing
`wire and extending from the proximal end of the catheter to
`a position beyond Said insertion port and to a position apart
`from the distal end of the catheter.
`22. A thrombus Suction catheter, comprising a tube having
`a lumen passing through from a proximal end to a distal end
`and a distal end opening having an angled cut Surface, at
`least a part on the proximal end Side of the cut Surface being
`formed in a concave shape in the angled direction and the
`distal end side of the cut surface being formed to be flat and
`flexible, in the distal end opening.
`
`Page 16
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`Medtronic Exhibit 1825
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