An extraction device for the removal of clots and foreign bodies from vasculature. The extractor device is connected to an elongate mandrel and is located within a longitudinally extending lumen defined by a catheter. A clot or foreign material extracted from a vessel by moving the extraction device and catheter proximally until the clot or foreign material does not perfuse a critical organ.
1. A device for removing unwanted material from vasculature, comprising:
an elongate wire having a distal end; and
a mesh structure, the mesh structure originating from one side of the wire.
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an elongate wire having a distal end; and
a material engaging structure attached to the elongate wire, the material engaging structure including a plurality of members originating from one side of the wire and from substantially a common longitudinal position therefrom.
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The present invention relates to medical devices that are useful in treating thromboembolic disorders and for removal of foreign bodies in the vascular system.
Thromboembolic disorders, such as stroke, pulmonary embolism, peripheral thrombosis, atherosclerosis, and the like, affect many people. These disorders are a major cause of morbidity and mortality in the United States.
Thromboembolic events are characterized by an occlusion of a blood vessel. The occlusion is caused by a clot which is viscoelastic (jelly like) and is comprised of platelets, fibrinogen and other clotting proteins.
When an artery is occluded by a clot, tissue ischemia (lack of oxygen and nutrients) develops. The ischemia will progress to tissue infarction (cell death) if the occlusion persists. Infarction does not develop or is greatly limited if the flow of blood is reestablished rapidly. Failure to reestablish blood-flow can lead to the loss of limb, angina pectoris, myocardial infarction, stroke or even death.
Occlusion of the venous circulation by thrombi leads to blood stasis which can cause numerous problems. The majority of pulmonary embolisms are caused by emboli that originate in the peripheral venous system. Reestablishing blood flow and removal of the thrombus is highly desirable.
There are many existing techniques employed to reestablish blood flow in an occluded vessel. One common surgical technique, an embolectomy, involves incising a blood vessel and introducing a balloon-tipped device (such as the Fogarty catheter) to the location of the occlusion. The balloon is then inflated at a point beyond the clot and used to translate the obstructing material back to the point of incision. The obstructing material is then removed by the surgeon. While such surgical techniques have been useful, exposing a patient to surgery may be traumatic and best avoided when possible. Additionally, the use of a Fogarty catheter may be problematic due to the possible risk of damaging the interior lining of the vessel as the catheter is being withdrawn.
Percutaneous methods are also utilized for reestablishing blood flow. A common percutaneous technique is referred to as balloon angioplasty where a balloon-tipped catheter is introduced to a blood vessel, typically through an introducing catheter. The balloon-tipped catheter is then advanced to the point of the occlusion and inflated in order to dilate the stenosis. Balloon angioplasty is appropriate for treating vessel stenosis but is generally not effective for treating acute thromboembolisms.
Another percutaneous technique is to place a microcatheter near the clot and infuse streptokinase, urokinase or other thrombolytic agents to dissolve the clot. Unfortunately, thrombolysis typically takes hours to days to be successful. Additionally, thrombolytic agents can cause hemorrhage and in many patients the agents cannot be used at all.
Another problematic area is the removal of foreign bodies. Foreign bodies introduced into the circulation can be fragments of catheters, pace-maker electrodes, guide wires, and erroneously placed embolic material such as thrombogenic coils. There exists retrieval devices for the removal of foreign bodies, certain of such devices form a loop that can ensnare the foreign material by decreasing the size of the diameter of the loop around the foreign body. The use of such removal devices can be difficult and sometimes unsuccessful.
Various thrombectomy and foreign matter removal devices have been disclosed in the art. However, such devices have been found to have structures which are either highly complex or lacking in sufficient retaining structure. Disadvantages associated with the devices having highly complex structure include difficulty in manufacturability as well as use in conjunction with microcatheter. Other less complex devices tend to pull through clots due to in part to the lack of experience in using the same or are otherwise inadequate in capturing clots or foreign bodies.
Moreover, systems heretofore disclosed in the art are generally limited by size compatibility and the increase in vessel size as the emboli is drawn out in the distal vascular occlusion location to a more proximal location near the heart. If the embolectomy device is too large for the vessel it will not deploy correctly to capture the clot or foreign body and if too small in diameter, it cannot capture clots or foreign bodies across the entire cross section of the blood vessel. Additionally, if the embolectomy device is too small in retaining volume, as the device is retracted, the excess material being removed can spill out and be carried by flow back to occlude another distal vessel.
Thus, there exists a need for an extraction device that can be easily deployed into the circulatory system for the effective removal of clots and foreign bodies. There is also a need for a device which could be used as a temporary arterial or venous filter to capture and remove thromboemboli formed during endovascular procedures.
The present invention is directed to devices that are useful in removing clots and foreign bodies from vessels. Various embodiments and method of use are disclosed for the effective removal of clots or foreign bodies. It is contemplated that the present invention may be used in all vasculature including the neurovasculature.
In one aspect of the invention, an elongate generally linear wire is provided for the removal of certain types of undesirable matter found in a blood vessel. The elongate generally linear wire is placed within the undesirable matter and rotated to thereby catch the matter and wind it about the wire. Withdrawing the wire within a receiving tube or directly through the vessel operates to extract the undesirable matter from the patient's vasculature.
In another aspect of the invention, a staged filter/emboli extractor is provided to remove clots or foreign material from a vessel. In one embodiment, a plurality of spaced-apart radially extending structures are configured on an elongate wire or tubular mandrel proximal a distal end of the mandrel. The radially extending structures are characterized by increasing in size from the most proximal structure to the most distal structure. In a presently preferred embodiment, each of the radially extending structures are in the form of a plurality of loops or petals arranged in an annular radial array about the circumference of the mandrel. In an alternative embodiment, each of the plurality of loops or petals originate from a common side of the mandrel and can be concentrically arranged.
In yet a further aspect of the invention, a knitted or mesh structure is provided for the removal of clots or foreign material from a blood vessel. The knitted or mesh structure is configured near the distal end portion of an elongate wire or tubular mandrel. In one presently contemplated embodiment, the knitted or mesh structure is affixed in a conventional manner to the distal end of the mandrel. In another presently contemplated embodiment, the knitted or mesh structure surrounds a distal portion of the mandrel and may additionally embody structure enabling one end of the knitted or meshed structure to be translated longitudinally with respect to its other end which is held fixed. The knitted or mesh structures disclosed are further characterized by having open or closed ends or a basket-like configuration.
The invention also includes an elongate tubular delivery catheter with at least one lumen for receiving an extractor device and for retaining the distal portion thereof in a reduced profile. The delivery catheter may be used in conjunction with an elongate insertion catheter that is configured to be introduced into a large vessel and advanced within a patient's vasculature.
Generally, the clot is extracted from a vessel by capturing the same and withdrawing the clot or foreign material proximally until it can be removed or released into a different vessel that does not perfuse a critical organ. The structure disclosed can also be used as a temporary arterial or venous filter to capture and remove thromboemboli formed during endovascular procedures. By removing the device from the body, the clot or foreign material is also removed.
Other features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.
The present invention is useful for the removal of clots or foreign material from vasculature. The present invention is intended to be used in various sized vessels and in vessels having varying degrees of tortuosity. Of particular significance is the contemplated use of the preferred embodiment in the highly tortuous neurovasculature. Moreover, the disclosed extraction devices are characterized by having structure that is useful as filter devices.
The elongate wire 24 may comprise a conventional guidewire or other wire structure having similar properties. One material of choice may be Nitinol. Its exterior may be scored or include other surface irregularities (not shown) for the purpose of enhancing engagement with certain types of clots or foreign bodies found in a patient's vasculature. Its outer diameter is such that it can easily slide within the lumen 26 of the catheter 28. Generally, the elongate wire 24 has a length greater than that of the catheter 28 so that its proximal end can be grasped by an operator and so that the elongate wire can be advanced and withdrawn independently of the catheter 28.
The delivery catheter 28 can be any commercially available catheter that is made out of any appropriate biologically compatible material. Typically, the catheter will have a single lumen 26 as constructed out of a flexible elastomeric material such as silicone, rubber, polyvinylchloride, polyeurothanes, polyesters, polytetrafluoroethylene and the like. The catheter has to be flexible enough and long enough to navigate through blood vessels to the occluded vessel where clots or other foreign bodies 20 are located. Typically the catheter will range in length from about 20 to about 175 centimeters.
The outer diameter of the catheter can also vary. Typically, the outer diameter will range from about 2 to about 10 F (IF equals 0.013 inch). The inner diameter will range from about 1 to about 9 F.
In use, the elongate wire 24 and catheter 28 are inserted into a patient's vasculature using conventional techniques, using fluoroscopy or other conventional means. The elongate wire 24 and catheter 28 are advanced within a patient's vasculature 22 to the location proximal to the clot or foreign body 20 to be extracted. The elongate wire 24 is then advanced independently of the delivery catheter 28 and across the clot or foreign material 20. Next, the elongate wire 24 is rotated to thereby catch the clot or foreign material 20 and wind it about the elongate wire 24. Thereafter, the elongate wire 24 with the clot or foreign material adhered thereto is withdrawn within the delivery catheter 28 and both the elongate wire and delivery catheter are removed from the patient's vasculature. Alternatively, the elongate wire 24 is directly removed from the patient's vasculature without first withdrawing it within the delivery catheter 28.
It has been observed that the elongate wire 24 is particularly useful in capturing fibrin clots. As shown in
A second preferred embodiment of the present invention is shown in
The number of petals or loops 46 of a radially extending structure 42 can range from 3–8 or more depending on the size of the petal or loop. The petal or loop itself can have a circular or generally oval configuration with its opening defining a space having a cross-section ranging from 0.050 inches or smaller to 2.125 inches and larger across. The wire used to form the loops 46 can be made of NiTi wire having a diameter ranging from 0.002–0.0055 inches or more.
In a preferred embodiment of the staged filter/emboli extractor 40, there are three spaced-apart radially extending structures formed on the mandrel 44. The petals/loops are configured to project from the mandrel 44 at a distally directed angle and are characterized by increasing in size or cross-sectional profile as one moves distally along the mandrel 44. However, it is to be recognized that as few as one and as many as eight or more radially extending structures can be configured on the mandrel 44. Moreover, depending on the application, the petals can project at a proximally directed angle and can either decrease in size or cross-sectional profile or vary as one moves distally along the mandrel 44.
The mandrel 44 has to be relatively stiff to support the staged filter/emboli extractor 40. In the preferred embodiment, the insertion mandrel is made out of stainless steel and is a solid wire from about 0.005 to about 0.038 inches in diameter. Other materials can be used such as hard plastic, Nitinol, and the like to make the insertion mandrel. The insertion mandrel is 10–20 centimeters longer than the catheter such that the operator of the device (typically a physician) can control the insertion mandrel 44 by gripping the proximal end which extends from the proximal end of the delivery catheter 28 with which it is used.
With reference to
Next, a coil retainer 60 is slipped over a ceramic (non-solderable) rod 62 projecting from a support 64. The remaining lead ends 54 of the loops/petals 46 are then placed between the ceramic rod 62 and coil retainer 60. Thereafter, the remaining lead ends are soldered to the retainer 60. The soldered assembly is removed from the ceramic rod 62 and is ready to be affixed to the mandrel 44 in any conventional manner including soldering or using adhesives.
Multiple loops/petals 46 can alternatively be simultaneously manufactured using a similar procedure. Generally, manufacturing the loops/petals 46 can be accomplished by looping a single wire 50 about a combination of rods that form the loops/petals as well as an auxiliary rod from which the loops/petals originate. Thereafter, the multiple loops can be affixed directly to a mandrel 44 or first cut and then affixed thereto.
In operation (see
The extractor 40 and catheter 28 are then inserted into a patient's vasculature using conventional techniques. Using fluoroscopy or other conventional means, the extractor 40 and catheter 28 are advanced within a patient's vasculature 22 to a location proximal to the clot or foreign body 20 to be extracted. The delivery catheter 28 with extractor 40 contained therein is then advanced so that the delivery catheter 28 traverses the clot or foreign body 20 to be extracted. The staged filter/emboli retractor 40 is then advanced independently of the delivery catheter 28 so that the radially projecting structures 42 are positioned distally with respect to the clot or foreign body 20.
When the extractor 40 is so positioned, the radially projecting structures 42 are permitted to spring outwardly and assume an uncompressed or less compressed configuration, the angle of the loops/petals 46 with respect to the mandrel 44 being defined during the manufacturing process.
Subsequently, the staged filter/emboli extractor 40 is withdrawn into engagement with the clot or foreign material 20 for the purpose of capturing the same. While withdrawing the extractor 40 rotational movement may be applied for the purpose of enhancing the ability of the extractor 40 to capture the clot or foreign material 20. As the extractor and delivery catheter 28 are continued to be withdrawn proximally, the entirety of the clot or foreign material 20 is removed from the vessel. It is contemplated that the radially projecting structures 42 are relied upon to extract the clot or foreign body 20 without the interaction of the delivery catheter 28. Alternatively, it is also contemplated that the extractor be withdrawn within the delivery catheter once it has engaged and captured the clot or foreign material 20.
It is to be recognized that use of combined staged variable sized elements in a single device such as the staged filter/emboli extractor has a number of advantages. That is, when deployed in a distal anatomy, distal to an emboli for an example, the correct size radially extending structure 42 engages the emboli first. As the emboli is retracted to larger vessels, if the first radially extending structure 42 is too small in diameter or volume, any “spilled” material can be caught by a subsequent radially extending structure 42. Moreover, employing multiple radially extending structures 42 on the extractor 40 inherently has the advantage of engaging a clot or foreign material 20 a multiple of times, thereby assuring that any undesirable matter left behind after a first pass will be collected during subsequent passes.
With reference to
Moreover, in certain situations it might be beneficial to employ a mandrel 44 which further includes a lumen (not shown) which extends substantially the length of the mandrel 44. Such a mandrel 44 could then be threaded over an appropriate sized guidewire in order to facilitate the advancement of the extractor 40 within a patient's vasculature.
Various other embodiments of extractors may be useful in removing undesirable material from blood vessels. Such other embodiments of extractors can be deployed distally with respect of the undesirable material and withdrawn or they can be directly deployed within such undesirable material and thereafter removed from the blood vessel. Moreover, other such embodiments of extractors may be used in conjunction with a delivery catheter 28 which operates to deliver the extractor to the repair site as well as releasably hold the extractor in a compressed configuration.
In order to manufacture the knitted or braided structure of the aforementioned extractors, either a plurality of wires or a single wire can be used. It is contemplated that the wires be comprised of Nitinol or other materials having similar properties. In the event a plurality of wires are used to form the knitted or mesh structures, four spaced-apart wires for example, may be wrapped in helical fashion in a clockwise direction about a mandrel (not shown) having a desired profile. The forming mandrel itself is used to define the profile of the resulting extractor configuration. An additional like number of spaced wires could simultaneously be helically wrapped in a counter clockwise direction in an over/under pattern with the wires being wrapped about the mandrel in a clockwise direction to thereby form the desired knitted or mesh configuration. Alternatively, a single wire can be wrapped in a helical fashion about a mandrel (not shown) that includes a plurality of pegs extending from the ends of the mandrel, the pegs being employed to aid in reversing the direction of winding. An over/under pattern of winding may also be employed to produce the desired knitted or mesh structures. A particular advantage of using one wire to form the knitted or mesh structure is that such a resultant structure is characterized by having atraumatic ends, a high expansion ratio and high flexibility.
The size of the filament or wire employed to construct the braid as well as angles between the filaments can be selected for the particular application. Moreover, the radial and longitudinal dimensions of the braid structure can likewise be varied for a particular application. However, the same effective range of dimensions contemplated for the second and third embodiments described above would be acceptable for the knitted or braided embodiments.
The extractors/filters and delivery catheter systems heretofore described are also contemplated to be used with an insertion catheter. A particularly useful insertion catheter is illustrated in
In practice, the insertion catheter 150 is inserted through a large vessel and through the vascular system to a position near a clot or foreign body in an occluded artery under fluoroscopic guidance. The delivery catheter 28 is then inserted through port 152 and through the insertion catheter 150 such that the distal end of the catheter 28 has passed the distal end 156 of the insertion catheter 150. The delivery catheter 28 or extractor is then translated across the clot or foreign body (not shown). The mandrel is then translated proximally to ensnare the foreign body or clot which is then translated toward the distal end 156 of the insertion catheter 150. Once the clot or foreign body is at the distal end 156, suction is applied via port 154 to suck part of the same into the distal end 156. Thereafter, the insertion catheter 150, the delivery catheter 28, the extractor and undesirable material are removed from the patient.
It is also contemplated that the present invention can be used as a filter in a blood vessel. In such a situation, the above-described extractors are deployed within a blood vessel and held stationary for a period of time sufficient for the extractor to remove unwanted material from a patient's bloodstream.
Thus, an extractor system is disclosed which allows for the removal of thromboembolic material and foreign bodies from a blood vessel. While several particular forms and applications of the invention have been illustrated and described, it will be apparent to those skilled in the art that many more modifications are possible without departing from the spirit and scope of the invention. The invention, therefore, is not to be restricted except in the spirit of claims appended hereto.