Patent Application
20140187961
The present invention relates to a catheter having an imaging function, and an intravascular observation system for observation of the inside of a blood vessel.
Among the various endoscopes (inclusive of catheters containing imaging function therein) to be inserted in living organisms, an endoscope to be inserted into the blood vessel sometimes has a device called balloon on the tip part thereof to interrupt the blood flow, so that an observation target site (intravascular wall and the like) can be seen (e.g., patent documents 1, 2 and the like).
Balloon is generally used along with a channel for intravascular injection of physiological saline.
As schematically shown in
On the other hand, cardiac disease patients are increasing in recent years due to the changes in lifestyle, aging and the like, along with which the demand for a treatment by intravascular insertion of a medical equipment such as catheter and the like (intravascular surgery) is also increasing. Intravascular surgery is advantageous in that it can be performed while visually observing the blood vessel lumen, and observing the detailed shape and color tone of the lesion with the naked eye, and is minimally invasive.
However, the present inventors have studied in detail the intravascular surgery including blood flow interruption with balloon, and found the following problem.
The problem is that, in an intravascular surgery including interruption of blood flow with balloon and substitution of blood with physiological saline to enable visual observation of the intravascular wall, long-time observation is not available, since it requires prevention of blood flow to the observation site by inflating the balloon located on the upstream side of the blood flow. In large blood vessels such as aorta and the like, moreover, application of balloon interrupts the blood flow from the heart (left ventricle) and blocks the systemic blood circulation. Therefore, application of balloon is difficult; hence, a treatment with visual observation is also difficult.
To solve the above-mentioned problem, the present inventors first provided a cylindrical-shaped hood (hood, cover) 600 on the tip of an endoscope body 500, as shown in
Using the hooded endoscope, as shown in
However, the present inventors have verified in more detail the observation capability of the above-mentioned hooded endoscope they proposed and noted the following points yet to be improved.
(a) It is ideal in the above-mentioned hooded endoscope to tightly enclose the observation target site with the hood so that an opaque fluid such as blood and the like will not enter into the hood from the periphery. In actual operation of an endoscope, however, it is difficult to bring the whole circumference of the hood opening in close contact with the wall surface around the observation target site, as in
(b) When a transparent fluid is injected into the hood, the transparent fluid flows out from the hood through the gap between the hood and the observation target site. In this case, as shown in
patent document 1: JP-A-2002-112954
patent document 2: JP-A-2007-289231
patent document 3: JP-A-H10-514603
patent document 4: WO1999/049910
patent document 5: WO2006/000942
The purpose of the present invention is to solve the above-mentioned problem, and provide an equipment that enables visualization of an observation target site with a less amount of a transparent fluid even in a suspended fluid such as inside of a blood vessel, and a system for effectively utilizing the equipment.
The present inventors have conducted intensive studies in an attempt to further improve the above-mentioned hooded endoscope they proposed and found that, in a structure wherein at least a part on the tip side in the whole circumference of the opening of the hood is bent toward the inside of the hood, a transparent fluid injected in the hood hits the bent part and stays in the hood and near the opening, whereby the inside of the hood can be effectively made transparent even when the opening of the hood is apart from the observation target site and the injection amount is small, which resulted in the completion of the present invention.
Accordingly, the main constitution of the present invention is as follows.
a tubular body, and
a hood extending forward from the outer periphery of the tip of the tubular body, wherein
the aforementioned tubular body comprises at least a fluid delivery channel for injecting forward a fluid from the tip of the tubular body, and an imaging channel for observation of the external environment from the tip of the tubular body, and a bending mechanism capable of bending a section with a predetermined length from the tip of the tubular body toward at least one lateral direction is provided,
the aforementioned hood has a basic shape of a cylindrical shape, or a hollow circular truncated cone shape enlarging toward the tip, the tip of the hood has a shape obtained by obliquely-cutting the aforementioned basic shape, the hollow in the hood opens at the tip face thereof and, in addition thereto, in the wall part of the outer periphery of the tip of the hood, at least a part located at the tip is bent toward the inside of the hood to prevent the flow of the aforementioned fluid heading toward the outside from a part located at the tip of the aforementioned opening.
the outer diameter of the tip of the tubular body is narrower than the outer diameter of the body from the proximal part to an intermediate part of the tubular body, and the hood extends enlarging forward from the outer periphery of the tip,
the maximum outer diameter of the tip of the hood is the same as the outer diameter of the body from the proximal part to the intermediate part of the tubular body.
the bending direction by the bending mechanism and the direction of inclination of the hood opening are related such that the tip of the tubular body part bends toward the direction that brings a line segment connecting A and B closer to parallel to the central axis of the catheter or a direction opposite therefrom, wherein A is a point located at the tip side of the outer periphery of the opening at the tip of the hood and B is a point located at a rear end side thereof.
a fluid delivery device for delivering a transparent fluid to the fluid delivery channel to inject the transparent fluid from the tip of the fluid delivery channel contained in the tubular body of the catheter, and
a control device for controlling driving of the fluid delivery device, wherein
the fluid delivery device is constituted to be controlled by the control device to perform or stop delivery of the fluid to the fluid delivery channel, and
the control device is constituted to receive a signal indicating the heart motion of a patient to be inserted with the aforementioned catheter as an input signal, and control the fluid delivery device based on the input signal to inject a predetermined amount of the transparent fluid from the tip of the fluid delivery channel of the aforementioned catheter, during the period when the blood flow stops at the tip of the catheter.
while an imaging channel in a tubular body contained in the catheter is constantly imaging the observation target site, it is constituted such that the control device starts recording of images in synchronization with the timing of the injection of a transparent fluid from the fluid delivery channel and performs recording of images only for a predetermined time.
while an imaging channel in a tubular body contained in the catheter is constantly imaging the observation target site, it is constituted such that the control device starts recording of images in synchronization with the timing of the injection of a transparent fluid from the fluid delivery channel and performs recording of images only for a predetermined time.
The “catheter” in the present invention is a [hollow, tubular equipment to be inserted into cavity, lumen, blood vessel and the like]. It may be a tubular-shaped medical equipment to be inserted in the body, as well as a tubular equipment insertable into an article.
The “channel” in the present invention means a pathway constituted to convey the object action such as conduit line, electrical line, waveguide line, heat transfer line and the like, and includes not only a simple transmission pathway but also a device and a structure constituted to perform the action such as [electrical line connecting a proximal end and a tip, and a tip light emitting (imaging) device].
The “imaging channel” in the present invention means a pathway and a device such as a camera at the tip and electric line or an optical fiber and the like, which are constituted to take images at the tip and send the obtained images to a proximal part.
The “fluid injection channel” in the present invention means a pathway such as conduit line, space and the like and a device, which are constituted to deliver a fluid sent from a proximal part to the tip side and allow discharge from the tip.
The “catheter having an endoscope function” in the present invention may be a catheter as a tubular equipment provided with imaging parts therein to exhibit an endoscope function, or a catheter inserted with an endoscope as an independent product therein, or an endoscope itself. Therefore, a constitution wherein an imaging channel and a fluid delivery channel are provided in a tubular body more specifically includes, but is not limited to, the following embodiment, and any combination can be adopted.
(A) An embodiment wherein the tubular body is a simple tube, the imaging channel is an independent endoscope, and the fluid delivery channel is an independent tube for fluid delivery.
(B) An embodiment wherein the tubular body is a simple tube, the imaging channel is an independent endoscope, and the fluid delivery channel is the remaining space in the tubular body.
(C) An embodiment wherein the tubular body is an outside tube of an endoscope, and a fluid delivery channel is formed in the endoscope. In this case, the catheter can also be said to be an endoscope having a fluid delivery channel therein.
Among the above-mentioned various embodiments, the embodiments of the above-mentioned (A), (B) wherein an endoscope having an ultrafine diameter is inserted into a simple tube used as a catheter are preferable, since more existing products can be utilized as parts, production is easy because the structure is simpler as compared to the one shown in
The catheter according to the present invention is provided with a hood having a cylindrical shape or circular truncated cone shape as a basic shape at the tip of the tubular body, and the tip has an obliquely-cut shape. As a result, as shown in
Furthermore, in the catheter according to the present invention, as shown in
By bending the hood tip as mentioned above, the transparent fluid f injected from a fluid injection channel 11 is deprived of the smooth flow out as in
Moreover, as shown in
When the catheter according to the present invention is applied as an endoscope for intravascular observation, the present invention takes note of the point at which the blood flow changes due to the motion of the heart (particularly, the moment when the blood flow almost stops due to cardiac diastole), and proposes to effectively make the periphery of an observation target site transparent by an injection of a small amount of a transparent fluid, by injecting a predetermined amount of a transparent fluid at a moment when the blood flow almost stops.
In the intravascular observation system according to the present invention, the control system is constituted such that the aforementioned [injection of a transparent fluid synchronized with the moment when the blood flow almost stops] can be achieved, wherein a motion signal of the heart is an input, and an appropriate amount of a transparent fluid is injected in the hood at an appropriate timing of the moment when the blood flow almost stops to effectively make the periphery of an observation target site transparent, thus enabling imaging.
In a preferable control constitution of the present invention, imaging or recording of images can be performed in synchronization with the aforementioned injection of a transparent fluid, namely, at the timing when the hood is made transparent.
The catheter according to the present invention is constituted to have, as shown in
As shown in
The basic shape of the hood 2 is a cylindrical shape, or a hollow circular truncated cone shape enlarging toward the tip, as in
The fluid injection channel 11 delivers the transparent fluid f into the hood, and the imaging channel 12 takes photographs of the external environment from within the hood. The tip of the hood 2 has a shape obtained by obliquely-cutting the aforementioned basic cylindrical shape or circular truncated cone shape (cylindrical shape in the example of Figure), and the hollow in the hood opens at the tip face thereof. In the present invention, the hood is further deformed, and the hood tip 22 is bent toward the inside of the hood to prevent the flow of the aforementioned transparent fluid f heading toward the outside from a part located at the tip of the aforementioned opening.
By the above-mentioned constitution, as explained in the above-mentioned Effect of the Invention, the tip of the tubular body 1 can be bent to position the hood to cover an observation target site and, in this state, a transparent fluid (physiological saline and the like) f is injected in the hood from the fluid injection channel 11. As a result, the flow thereof hits a hood tip 22 and stays, for example, as shown by the thick arrow in
The catheter can be used not only for medicine but also for any application including visual observation, from the outside, of an observation target site in an opaque fluid. The catheter is preferable for the observation of various parts in the body, inter alia, use in blood vessels, and particularly useful for large blood vessels where use of balloon is not preferable, such as ascending aorta, aortic arch, descending aorta and the like.
To know the basic internal structure of each part from the tip of the imaging channel and fluid delivery channel to the proximal operation parts thereof, the mechanism for transmitting various information of the tip to the proximal side, the mechanism for transmitting operation on the proximal side to the tip side and the like of the catheter, the mechanisms mounted on conventionally-known catheters and endoscopes can be referred to (e.g., patent document 3 and the like).
At least a fluid injection channel and an imaging channel are formed in the tubular body. It is preferable to add a lighting channel for imaging.
When not only images of an observation target site is simply taken but also various in situ treatments are performed on the observation target site (mechanical treatment for cutting, partial removal and the like of an observation target site, treatments such as heating, application of electric current, voltage, irradiation of laser beam, medication, fluorescence observation, obtaining tomographic image and the like with respect to an observation target site), various optical fibers and channels may be added such as forceps channel, special light irradiation fiber, Optical Coherence Tomography (OCT) probe channel and the like.
The outer diameter and inner diameter of the main body of the tubular body are not particularly limited. For industrial use such as observation of the inside of a piping and the like, the maximum outer diameter is about 15 mm, maximum inner diameter is about 10 mm; for medical use, the maximum outer diameter is about 10 mm, and the maximum inner diameter is about 8 mm. Among others, for intravascular observation use, the maximum outer diameter of the body of the tubular body is about 6 mm, and the maximum inner diameter is about 5 mm, more preferably, the maximum outer diameter is about 5 mm and more preferable maximum inner diameter is about 4 mm.
On the other hand, the minimum diameter of the main body of the tubular body only needs to be a size permitting provision of an endoscope function in the inside, or permitting insertion of an endoscope. When a bending mechanism, an imaging channel, and a fluid delivery channel are set inside thereof, the minimum outer diameter of the tubular body at this point is about 6 mm, and the minimum inner diameter is about 5 mm. With the progress of the technique for making the diameter thinner, the minimum diameter of the tubular body may be reduced as appropriate. When a topically narrow or thick part needs to be formed to meet the design needs, as in the embodiment shown in
The inner diameter may be changed as appropriate according to the strength of the material of the tubular body.
For the purpose of intravascular observation, a preferable minimum outer diameter of the main body of the tubular body is about 3 mm, practically more preferably about 4 mm, in view of the mechanical strength of the hood, the structure of the connection part between the tubular body and the hood, fluid resistance of the fluid delivery channel and the like.
While the material of the tubular body is not particularly limited, when it is used as a general medical catheter, polyurethane, polyester, polyolefin, fluorine-based resin (e.g., Teflon (registered trade mark)), nylon, silicone rubber, and the like are preferable materials.
While the tubular body may be formed from the same material over the full-length, the material may be changed depending on the part. For example, a flexible material may be used for a part to be bent by the bending mechanism, a highly rigid material is used for other parts and the like.
When the fluid delivery channel is an independent tube, the inner diameter thereof can be appropriately determined depending on the outer diameter of the main body of the tubular body, and the presence of other channels.
For example, for the purpose of intravascular observation, a preferable outer diameter of the main body of the tubular body is 4 mm-6 mm, as mentioned above, and a preferable inner diameter of the fluid delivery channel in this case is about 1 mm-2 mm.
The injection port at the tip of the fluid delivery channel may be a simple opening, or a nozzle or orifice having an intended increase in the angle and flow rate, which is designed to be able to discharge a transparent fluid.
When the fluid delivery channel is an independent tube, the material of the tube is not particularly limited, and a tube material used for catheter and endoscope can be used. For example, polyurethane, polyester, polyolefin, fluorine-based resin (e.g., Teflon (registered trade mark)), nylon, silicone rubber, and the like are preferable.
The transparent fluid to be injected from the fluid delivery channel may be a gas or liquid, depending on the situation and environment under which an observation target site is placed, and a combination with an obstacle.
For example, for application to the inside of a suspended sewer piping, the transparent fluid may be water. For intravascular application, the transparent fluid may be physiological saline or, in a preferable embodiment, a predetermined amount of the patient's own blood plasma or blood serum taken in advance is used.
As the injection flow of the transparent fluid, an amount that enables rapid observation can be appropriately determined according to the outer diameter of the catheter, inner diameter of the hood, viscosity of an opaque fluid to be excluded and the like.
When the catheter is intravascularly applied and physiological saline is injected as a transparent fluid in the hood with an inner diameter of about 5 mm-4 mm, an injection time of the physiological saline is preferably about 0.1 [second]-0.3 [second] when it is synchronized with the timing when the blood flow stops. The flow rate of physiological saline is preferably about 2 [mL/second]-5 [mL/second], and can be about 1 [mL/second]-3 [mL/second] in view of the stay action in the hood tip.
The imaging channel may be an image guide that transmits images obtained at the tip to the proximal part through an optical fiber bundle, a constitution wherein a CCD camera is disposed at the tip and the image data is transmitted to the proximal part through a signal line and the like, or a constitution wherein the image data is transmitted wirelessly, and received by a receiver set outside the body.
To perform imaging at the tip more preferably, the catheter is preferably provided with a lighting channel. The lighting channel may be an embodiment of a light guide wherein the light is transmitted from the proximal part to the tip through an optical fiber, or an embodiment wherein a light emitting element such as LED and the like is disposed at the tip and light emission is operated at the proximal part through an electric cable and the like and the like, and the type of light source is not limited.
As shown in
The bending mechanism is preferably a mechanism that can bend a tubular body from a linear state toward one lateral direction and permits the tubular body to return to the original linear state. Depending on the use, a mechanism capable of bi-directional bending and stretching motion is preferable, which includes returning from the aforementioned one lateral direction to the original linear state, and further, a similar bending and stretching motion to the opposite side. The aforementioned bending to the opposite side enables covering of an observation target site with a hood, corresponding to the bending of the blood vessel.
Examples of the bending mechanism include a mechanism wherein a wire is disposed under the surface layer of the main body of the tubular body from the proximal part to the tip part along the longitudinal direction (constituted such that the tubular body can be bent at a predetermined part of the tip part by pulling the wire at the proximal part), a mechanism wherein the bending motion and restoring motion of a shape-memory alloy and a heater are appropriately combined (return spring is also used as necessary), a mechanism wherein an extremely compact air-cylinder is driven by compressed air, a mechanism using a polymer actuator, what is called an “artificial muscle”, and the like. The above-mentioned bi-directional bending and stretching motion can be achieved by, for example, placing a wire at respective positions 180 degrees opposite from each other on the outer circumference of the main body of the tubular body.
As for these bending mechanisms, various known techniques of catheter and endoscope can be referred to.
In an embodiment wherein the tubular body is a simple tube and an endoscope is inserted therein, the bending mechanism equipped to the endoscope may also be utilized.
The basic shape of the hood may be a cylindrical shape as shown in
The basic shape of the hood may be not only literally a cylindrical shape wherein the outer diameter and the inner diameter are constant along the central axis direction and literally a circular truncated cone shape wherein the outer diameter and the inner diameter increase linearly, but also may be added with a topical part having a different outer diameter and a different inner diameter as long as the object of the present invention can be achieved. Therefore, while the basic shape of the opening at the hood tip is also a simple ellipse obtained by obliquely cutting a cylindrical shape or circular truncated cone shape, it may be a cross sectional shape corresponding to the modification applied to the shape of the hood.
The [shape obtained by obliquely cutting] in the present invention expresses the resulting shape, and it may not be necessarily formed by obliquely cutting, but formed by using a mold having such shape.
The obliquely-cut plane may be a flat plane, or a surface curved along the surface of an observation target site.
In the present invention, as shown in
While the bending of the hood tip may be a topical bending of only that part, preferably as shown in
In the embodiment of
In the embodiment of
Examples of preferable size of each part are given by referring to the embodiment of
An angle (angle formed by central axis Y and tip face 261) θ1 of the [shape obtained by obliquely cutting] at the tip of the hood is preferably 30 degrees-60 degrees, more preferably 40 degrees-50 degrees. However, angle θ1 does not necessarily mean that one most preferably value exists, and each angle has its advantage. For example, when θ1 is as sharp as about 30 degrees, the hood advantageously covers an observation object part in the lateral direction widely by only bending a tubular body by 30 degrees. On the other hand, when θ1 is about 60 degrees, the tubular body of the hood needs to be bent up to 60 degrees to cover an observation target site in the lateral direction; however, the observation target site can be advantageously observed in a state closer to the straight gaze.
Angle θ2 formed by the boundary plane of bend [flat plane including line segment A2-B and perpendicular to paper plane] and the central axis Y determines where to start the bending, and about 50 degrees-70 degrees is preferable, and 55 degrees-65 degrees is more preferable.
Angle θ3 formed by the bent central axis Y′ and tip face 21 [flat plane including line segment A-B and perpendicular to paper plane] determines the level of bending (inclination of hood tip 22), about 65 degrees-85 degrees is preferable, and 70 degrees-80 degrees is more preferable.
As a result of the bending of hood tip 22, point A at the tip of the outer periphery of the opening of the tip of the hood protrudes into the hood. As shown in
The proportion of Δe in the inner diameter of the hood is preferably about 10%-20%. More specifically, when the inner diameter of the hood is about 4 mm-5 mm, the protrusion amount Δe is, for example, preferably about 0.4 mm-1.0 mm, more preferably about 0.6 mm-0.9 mm.
The difference between the outer diameter of the hood and the outer diameter of the tubular body is preferably small.
The hood and the tubular body may be integrated or parts separate from each other.
When the hood and the tubular body are formed as parts separate from each other, known connecting or jointing methods such as utilization of adhesive, heat seal, welding, screw-in joint, fitting, press, screw clamp, coupling and the like is appropriately used or combined to connect them.
a) is a cross-sectional view showing one embodiment wherein the opening of the hood is enlarged in a flared shape (circular truncated cone shape). By enlarging the hood, the field of view is widened, and a more preferable observation becomes possible. Also in this case, the hood tip 22 is bent inward, making an injected fluid to stay.
When the hood is deformed in this manner, for example, it is preferable to impart elasticity or stretchability to the hood material, so that the hood will be shrunk upon puncture into a blood vessel and the like and inflated after entry into the blood vessel.
As shown in this Figure, the tubular body 1 is narrower at tip part 1a than the body outer diameter at the proximal part—intermediate part, and a hood 2 extends enlarging forward while enlarging from the outer periphery of the tip thereof.
The amount of enlarging of the hood in this case is not particularly limited and, in view of the manner of insertion into the object, the maximum outer diameter of the tip is the same as the outer diameter of the body from the proximal part to the intermediate part of the tubular body in a preferable embodiment as in
Angle θ4 of expansion of the hood is preferably 25 degrees-45 degrees, more preferably 30 degrees-40 degrees.
In embodiment of
In the embodiments of
The cross-sectional area and cross-sectional shape of each of the fluid delivery channel can be appropriately determined in consideration of the flow rate of the fluid to be discharged.
The material of the hood may be any as long as it has mechanical strength, chemical resistance, environmental resistance, corrosion resistance, biocompatibility, flexibility, stretchability and the like according to the object, such as inorganic materials (e.g., metal, ceramics and the like), organic polymer materials (e.g., plastic, silicone rubber, and the like), and the like.
Metals such as titanium, stainless steel and the like are superior in mechanical strength. For example, when the outer diameter of the hood is 4 mm-6 mm, the thickness can be 0.3 mm-0.5 mm.
As the organic polymer material, polyolefin, polyamide elastomer and the like are preferable materials from the aspects of flexibility and pressure resistance.
While organic polymer materials such as polyolefin, polyamide elastomer and the like are soft and less often injure an observation target site, when the outer diameter of the hood is 4 mm-6 mm, the thickness is preferably about 0.5 mm-0.8 mm.
When the catheter is inserted into an object such as the living organism and the like, the hood tip of the catheter may be simultaneously monitored by blood vessel angiography.
In this case, a metal marker is preferably provided on the hood so that images of the blood vessel angiography display the hood even when it is a polymer.
Examples of a preferable metal material marker include stainless steel, titanium and the like.
Examples of the method for forming a metal marker on the hood include a method including embedding a stainless steel wire with an extra fine diameter in the hood along the longitudinal direction thereof as shown in
The relationship between the bending direction by the bending mechanism of the tubular body, and the opening of the hood is as follows.
As shown in
In actual assembly of the catheter, the direction of the opening of the hood only needs to be set in the bending direction of the bending mechanism of the tubular body.
The relationship between the configuration of each channel in the tubular body, and the inclination of the hood is preferably determined as appropriate in the bending state of the tubular body in consideration of the following actions.
(i) A fluid delivery channel is set at a position that permits more effective exclusion of an opaque fluid (blood and the like) when a transparent fluid is discharged from the fluid delivery channel.
(ii) An imaging channel is provided at a position more advantageous for imaging such as more preferable imaging of observation target site and the like.
(iii) When a lighting channel is formed, it is provided at a position more advantageous for lighting such as more preferable irradiation of light to an observation target site and the like.
(iv) As others, for example, when a forceps channel is formed, it is set at a position that ensures a space sufficient for the operation of the forceps according to the shape of the forceps to be used.
In the example of
In the present invention, it is proposed to mount an ultrasonic oscillator on the body of all catheters capable of observing ahead, inter alia, catheters capable of injecting a transparent fluid and imaging around the tip, and impart an ultrasonic diagnosis function of wall surface.
Ultrasonic oscillator is also called an ultrasonic transducer, and functions as an ultrasonication transmitting-receiving element in combination with an outside driving circuit. Ultrasonic diagnosis, particularly, intravascular ultrasound (IVUS), using an ultrasonic oscillator can obtain tomographic images of the inner wall over 360 degrees from the inside of the blood vessel.
The techniques per se for performing an ultrasonic diagnosis using an ultrasonic oscillator (material and structure of the oscillator, configuration of electric and electronic circuits for driving elements and transmitting and receiving ultrasonic waves, image display device and the like), and the techniques per se for applying same for an intravascular ultrasonic diagnosis are well known as described in, for example, the above-mentioned patent documents 4, 5 and the like.
However, since the equipment for intravascular ultrasonic diagnosis used conventionally simply mounts an ultrasonic oscillator on the body of a long and narrow equipment, such as catheter, it is defective in that it cannot obtain images ahead, though it can obtain images of the blood vessel wall.
Therefore, when ultrasonic diagnosis of blood vessel inner wall is actually performed by inserting an equipment for intravascular ultrasonic diagnosis and advancing the equipment to the object site, the equipment needs to be advanced depending solely on the feeling at the operation side, and an accident of breaking through the blood vessel wall with the tip of the equipment sometimes occurs.
In contrast, by mounting an ultrasonic oscillator 51 on the body of the catheter capable of imaging the blood vessel near the tip while injecting a transparent fluid as in
In addition, by mounting an ultrasonic oscillator for ultrasonic diagnosis on the body of the catheter of the present invention, lesions in the inside of the blood vessel wall (for example, atherosclerosis, calcification and the like) and elasticity property of the blood vessel (level of arteriosclerosis) can be known.
In the embodiment of
The embodiment of
As shown in the inner cross section of
In the present invention, when an ultrasonic oscillator for intravascular ultrasonic diagnosis is formed on the main body of the tubular body, an ultrasonic oscillator may be mechanically rotated along the periphery of the main body of the tubular body. However, the whole size becomes thick due to such rotation mechanism. As shown in
A channel for feeding a transparent fluid (e.g., physiological saline) may be formed in the inside of an endoscope 12a, the endoscope becomes thick. In contrast, an embodiment utilizing a space along the outside of the endoscope as shown in
Next, the constitution of an intravascular observation system using the catheter according to the present invention is explained.
This system is composed of at least the catheter C according to the present invention, a fluid delivery device 32, and a control device 30, as one embodiment of the constitution is schematically shown in
The control device 30 is constituted such that it can receive a signal indicating the motion of the heart of a patient to be inserted with the aforementioned catheter as an input signal. In the example constitution of
The control device 30 may be constituted mainly based on the sequence circuit. However, since a complicated signal control including monitoring and analyzing a signal indicating the motion of the heart of patients, and injecting a transparent fluid in an appropriate synchronization with the signal, an embodiment constituted mainly based on a computer, with which an operator can finely adjust the parameter of each timing on the screen or with an external control panel, is preferable.
An interface necessary for the connection of external devices such as pump, electromagnetic valve and the like and a control device, an image display device, a printer and the like can be formed as appropriate.
An important characteristic of the system is that the control device 30 is constituted to control a fluid delivery device 32 such that a signal showing the motion of the heart of patients (output signal of electrocardiogram device 33A in the example of
As a result, an operator of the catheter of the present invention delivers the catheter to an observation target site, operates the bending mechanism to enclose the observation target site with the hood, and discharges an appropriate amount of physiological saline in the hood at an appropriate time period when the blood flow stops, whereby the observation target site can be seen.
The fluid delivery device 32 may be a simple pump or cylinder that starts the motion of feeding a transparent fluid by the instruction from the control device 30. To inject a transparent fluid with a steep rise in accordance with the timing of cease of the blood flow, an embodiment wherein a transparent fluid is contained in a pressure container, the inside of the container is always pressurized with a compressed air, and the transparent fluid is injected or stopped by opening or closing an electromagnetic valve formed on an injection port of the container is preferable.
In the example of
In such imaging device, a camera (photographic equipment), a video camera and the like can be appropriately set according to the imaging channel or use object. When an imaging device such as a CCD camera and the like is included in the tip of the imaging channel, the signal output thereof may be directly input in the control device 30.
b) is a time chart showing the relationship between a signal from an electrocardiogram device (ECG output) indicating the motion of the heart of patients, and the timing of motion of an electromagnetic valve and the appropriate timing for taking images based on the signal, when a transparent fluid is constantly delivered by controlling an electromagnetic valve.
As shown in
Furthermore, a delay time period t3 from the motion start time T1 of the electromagnetic valve to the transparency in the hood is experimentally obtained, and image taking is started after lapse of the delay time period t3. t4 is an imaging time period based on the time period during which the transparency in the hood is lost.
The motion of the imaging channel may be constituted, as shown in
When an imaging channel always performs imaging of an observation target site and continuously outputs image signals, a control device may start recording of images in synchronization with the timing of injection of a transparent fluid, and perform recording of images only for a predetermined time period.
A circulation device that simulatively reproduces pulsation of the heart and variation in the blood flow associated therewith in the circulatory system of the human body was constituted and, using the device, the usefulness of the catheter and the system according to the present invention was confirmed.
The action of the closed chamber 41 for arterial pressure loading simulates the compliance (elasticity) of the artery that temporarily preserves the blood ejected from the cardiac ventricle (pulsatile flow pump) during cardiac systole.
The action of the venous system reservoir 43 simulates the action of the atrium that preserves the blood in order to deliver the blood at once to the cardiac ventricle during cardiac diastole.
The action of the resistance 42 simulates the resistance of the blood vessel (total peripheral circulation resistance).
The fluid that circulates in the pipe was a white turbid liquid obtained by mixing tap water with a commercially available white turbid bathing agent (main component: sodium hydrogen carbonate) at a ratio of 10 [g/L].
The operation characteristics of the above-mentioned circulation device are as follows.
frequency: 1 [Hz]
amplitude: 5 [Vp-p]
duty ratio: 30[%]
average internal pressure of closed chamber: 13.3 [kPa]
pulse pressure: 8.0 [kPa]
average flow rate: 6 [L/min]
A constitution wherein a flow meter 33B was connected immediately after the pump 44, which was the heart, to record a signal indicating the variation in the fluid flow in the pipe, and a driving signal of the pump 44 was input instead of electrocardiogram in the control device 30 of the system of the present invention.
In the observation site 45 in the pipe was disposed, as a target of the observation object, a concentric circular mark shown in
Image of this mark was taken, and how much the white turbid liquid was removed and how clearly the mark can be seen was evaluated by luminance difference. The “luminance difference” is shown in a numeric value converted with the luminance of the white part of the target as 255, and the luminance of the black part as 0 when filled with water.
The catheter system of the present invention applied to the above-mentioned circulation device is the same as that shown in
As for hood, the Example product was one having the shape shown in
In the Example product and the Comparative Example product, as shown in
In the Example product, as shown in
The constitution of the fluid delivery device was that transparent water was filled in a pressure container, the inside of the container was constantly pressurized to 0.3 MPa, and water was discharged and stopped by opening an electromagnetic valve set at an injection port of the container for 300 msec (discharge time period 300 msec). The spontaneous rate of the pump was 100 times per minute.
In addition, based on the variation in the fluid flow in the pipe by a flow meter 33B, each delay time was appropriately set, and discharge was made to be performed at an observation site at the moment when the water flow stops.
First, the tip of the hood face of the Example product catheter was maintained at about 1 mm apart from the surface of the target mark, and water was discharged. As shown in the graph chart of
In contrast, when the tip of the hood face of the Comparative Example product catheter was maintained in contact with the mark surface, and water was discharged, as shown in the graph chart of
When the tip of the hood face of the Comparative Example product catheter was maintained at about 1 mm apart from the surface of the mark, and water was discharged, the mark could not be identified clearly as shown in the graph chart of
From the above experiment, it was found that a mark can be clearly identified even when the tip face of the hood is apart from the mark surface according to the present invention.
How clearly the mark could be seen by the Example product when the internal pressure of the pressure container and the open time period (discharge time period) of the electromagnetic valve in the above-mentioned Example 1 were changed was confirmed.
In this Example, the internal pressure of the pressure container was set to 0.1 MPa, and the open time period (discharge time period) of the electromagnetic valve was set to 100 msec.
The results of the Example product in this Example (pressure 0.1 MPa, discharge time period 100 msec) are shown in the graph chart of
In addition, the results of the Example product in Example 1 (pressure 0.3 MPa, discharge time period 300 msec) are shown overlapped in the same graph chart of
The tip of the hood face of the Example product catheter was maintained at about 1 mm apart from the surface of the mark, and water was discharged (pressure 0.1 MPa, discharge time period 100 msec). As shown in the graph chart of
From the results of this Example, it was found that the mark could be observed even when the discharge pressure and the discharge time were decreased. The total discharge amount of water per one time decreased to 0.6 ml since the discharge pressure and the discharge time period were decreased, which has clarified that discharge and imaging can be performed many more times in living organisms. In addition, since the mark can be clearly identified even when the tip of the hood face is maintained at about 1 mm apart from the surface of the mark, it was found that the surface of the inner wall of the blood vessel can be continuously observed by rotating the tip of the catheter in the circumferential direction.
In this Example, a bile duct stent (length 45 mm, diameter 10 mm, material: nickel-titanium alloy) was inserted into the descending aorta of a swine (body weight about 30 kg) under general anesthesia, and an artificial blood vessel (length 15 mm, diameter 10 mm, material: dacron base, collagen coated) was anastomosed thereto. The catheter of the present invention was inserted backwardly from the abdominal aorta, physiological saline was discharged in synchronization with the cardiac electrogram of the swine, and visualization of the stent, artificial blood vessel, blood vessel branched part and the like was examined. At that time, the position of the catheter was identified by an angiography device (blood vessel angiography device).
The catheter was made from polyurethane, wherein the tubular body was a tube having an outer diameter of 6.2 mm and an inner diameter of 5.6 mm, an endoscope (outer diameter 1.4 mm) was inserted thereinto, and a hood was joined with the tip with a silicone rubber-based adhesive.
The hood had the same outer diameter, inner diameter with the tubular body, and the shape of the tip was similar to the hood of Example 1.
The constitution of the whole system is shown in
As shown in
c), (d) are endoscope imaging photographs when the artificial blood vessel was end-to-end anastomosed to the descending aorta.
As shown in the photographs of
In this Example, a stent (length 45 mm, diameter 10 mm, material: nickel-titanium alloy) was inserted into the thoracic aorta of a swine (body weight about 35 kg) under general anesthesia. Using a catheter having a hood with a flared shape (circular truncated cone shape) as shown in
The material of the hood was silicone rubber, and the spread angle was 35 degrees. Angle θ1 formed by the cylindrical-shaped central axis Y and the opening surface 21 was set to 30 degrees.
The aforementioned catheter was inserted from the abdominal artery, physiological saline was discharged in synchronization with the cardiac electrogram of the swine while confirming the visualized site by an angiography device, the aforementioned mark of the stent was observed.
As shown in the endoscope imaging photograph of
With the aim of improving the practicality and broad utility of the catheter and the intravascular observation system according to the present invention, a commercially available endoscope is inserted into an outer tube produced tentatively and used as the catheter of the present invention. A large blood vessel endoscope system was constituted, and a simulative basic characteristics test was performed in the same manner as in Example 1.
The catheter produced in this Example is the outer tube shown in
The commercially available flexible endoscope has a tip face shown in
The above-mentioned outer tube is largely divided into a connector part at the proximal side, an intermediate reinforced part, and a non-reinforced part on the tip side, as shown in
The reinforced part on the tip has a flexible structure free of the aforementioned braid so that it can bend by the head swing of the endoscope as shown in
The outer diameter of the non-reinforced part (excluding spread of the hood) and the reinforced part is both 4.8 mm, which is the size enabling an approach from the femoral artery of adult human.
As the material of the outer most covering layer of the outer tube, different polyamide resins are used for the non-reinforced part and the reinforced part. The non-reinforced part was made flexible by using a material having Shore D hardness of 25 as defined in JIS K6253, and a material having Shore D hardness of 40 (in a state without reinforcement by the above-mentioned tubular braid) was used for the reinforced part.
The constitutions of the external control device and piping for discharging physiological saline from the catheter and imaging are the same as those shown in Example 3 and
As in
Using the system constituted as mentioned above and the circulation device of
A pressure container charged with water instead of physiological saline was pressurized by a gas cylinder, and water was discharged by changing the internal pressure by 0.1 MPa between 0.1-0.4 MPa, and each flow rate [ml/min] was measured.
The experiment results are shown in the graph of
As shown in
The experiment results are shown in the graph of
In the same manner as in Example 1 and using the circulation circuit of
The discharge time period was changed between 100-200 msec and the internal pressure of the pressure container was changed between 0.1-0.2 MPa, and the mark was imaged while keeping the opening of the tip of the hood in a non-contact state by holding same at about 1 mm apart from the mark surface. In the same manner as in Example 1, and how much the white turbid liquid was removed and how clearly the mark can be seen was evaluated by luminance difference.
The experiment results are shown in the graph of
Using the catheter and the system of the present invention in a suspended opaque fluid such as in a blood vessel, an opaque fluid in the periphery of an observation target site can be effectively removed by dispensing a small amount of a transparent fluid even when an end surface of the hood is about 0.5 mm-1 mm apart from the observation target site, and the observation target site can be observed visually.
This application is based on a patent application No. 2011-080732 filed in Japan (filing date: Mar. 31, 2011), the contents of which are incorporated in full herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-080732 | Mar 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/058197 | 3/28/2012 | WO | 00 | 9/30/2013 |
