The disclosure herein relates generally to medical devices and methods. In particular, this disclosure relates to systems, methods and procedures for crossing chronic total occlusions in vasculature.
Cardiovascular disease is a leading cause of mortality worldwide. Cardiovascular disease can take many forms, and a variety of specific interventional and pharmaceutical treatments have been devised over the years with varying levels of success.
A particularly troublesome form of cardiovascular disease results when a blood vessel becomes totally occluded with atheroma or plaque, referred to as a chronic total occlusion (CTO). Until recently chronic total occlusions have typically been treated by performing a bypass procedure where an autologous or synthetic blood vessel is anastomotically attached to locations on the blood vessel upstream and downstream of the occlusion. While highly effective, such bypass procedures are quite traumatic to the patient.
Recently, catheter-based intravascular procedures have been utilized to treat chronic total occlusions with increasing success. Catheter-based intravascular procedures include angioplasty, atherectomy, stenting, and the like, and are often preferred because they are much less traumatic to the patient. Before such catheter-based treatments can be performed, however, it is usually necessary to cross the occlusion with a guide wire to provide access for the interventional catheter.
In some instances, crossing the occlusion with a guide wire can be accomplished simply by pushing the guide wire through the occlusion. After being advanced through the occlusion, the guide wire emerges in the blood vessel lumen and provides the desired access path. In many cases, however, the guide wire inadvertently penetrates into the subintimal space between the intimal layer and the adventitial layer of the blood vessel as it attempts to cross the occlusion. Once in the subintimal space, it is very difficult and in many cases impossible for a physician/user to direct the guide wire back into the blood vessel lumen. In such cases, it will usually be impossible to perform the catheter-based intervention and other, more traumatic, procedures may have to be employed. Catheters for use in treating chronic total occlusions are described in U.S. Pat. Nos. 4,405,314, 4,947,864, 5,183,470, 5,190,528, 5,287,861, 5,409,019, 5,413,581, 5,429,144, 5,443,497, and 5,464,395 as well as in International Publication Numbers WO 97/13463 and WO 97/13471. For these reasons, there is a need to provide apparatus and methods that facilitate the crossing of chronic total occlusions with guide wires.
Devices and methods are provided below that include catheters, guides, and/or other apparatus for use in crossing total occlusions in vasculature. The total occlusions are also referred to as total vascular occlusions or chronic total occlusions (CTOs). The devices/methods include medical devices for use by physicians/users with conventional and/or specialized guide wires to direct or redirect the guide wire from the subintimal space back into the blood vessel lumen after the guide wire has entered the subintimal space. These devices/methods are useful in the treatment of coronary artery disease in coronary arteries as well as other blood vessels and should be capable of being performed with or without imaging. The devices/methods are also useful for applications in other arteries and veins, such as the treatment of peripheral vascular diseases.
A total occlusion TO may comprise atheroma, plaque, thrombus, and/or other occluding materials normally associated with cardiovascular disease. By “total” occlusion, it is meant that the occluding material occludes substantially the entire lumen L of the artery or other blood vessel so that blood flow through the vessel is substantially blocked or stopped. The catheter systems and methods described herein are generally used with patients in which the totally occluded artery is not immediately life threatening since the tissue distal to the occlusion will often receive oxygenated blood from collateral arteries. Usually, however, the blood supply in regions distal to the occlusion will be insufficient and it will be desirable to treat the occlusion by an intravascular intervention, such as angioplasty, atherectomy, stenting, or the like, to restore blood flow through the affected vessel.
Total occlusions are crossed by positioning a guide wire, or blunt dissection catheter (as described in U.S. Pat. Nos. 5,968,064, 6,217,549, 6,398,798, 6,508,825, 6,599,304, and 6,638,247, for example) at the proximal end of the occlusion and advancing the device through the occlusion using conventional interventional methods. Crossing of the total occlusions is defined herein, in addition to any meanings provided by those skilled in the art, as establishing a longitudinal path from the proximal end of the occlusion to the distal end of the occlusion. The longitudinal path of the guide wire and/or blunt dissection catheter is to remain as central as possible within the occluded vessel and emerge in the true lumen of the vessel after having traversed the occlusion. In practice however, the guide wire or blunt dissection catheter often tracks an eccentric pathway through the occlusion and, after having been advanced beyond the distal end of the occlusion itself, is contained within a layer of vascular tissue that is distal to the terminal end of the occlusion. A dissection track of this type is generally referred to as a subintimal track, i.e. between the intimal layer and adventitial layer of the vessel, and is typically contained within the medial layer but is not so limited (
However, more often the disease state that forms a total occlusion erodes the inner layers of the vessel wall at the site of the occlusion, as described above with reference to
Therefore, taking into consideration that the vessel segment in the region of the occlusion may be either of normal structure (
Note, also, that there is a difference between a dissection tract that is contained within the total occlusion, and a dissection tract that is propagated beyond the total occlusion. When the dissection tract is propagated beyond the total occlusion, both types of subintmal tracks described above will be defined as being extra-luminal, i.e. outside the bounds of the vessel true lumen that is distal to the occlusion. The term “extra-luminal” only has relevance when the dissection track has been advanced beyond the distal end of the total occlusion. Note that a dissection track that is contained within a total occlusion can have no reference to an extra-luminal location, since no physical lumen exists within the occlusion. Hence for further reference, the subintimal tract distal to the occlusion is defined as extra-luminal, in addition to any meaning(s) provided by those skilled in the art.
Also notable is the difference between intra-vascular and extra-vascular locations. Since all dissection tracts described herein are contained within the boundary of the blood vessel, e.g. within the adventitial layer (AL), these are considered “intra-vascular”. Accordingly, all locations outside of the adventitial layer (AL) are termed “extra-vasculai”. Extra-vascular locations are not material to the discussions described herein.
Having now established the different structures found in diseased vessels, from the subintimal, extra-luminal locations previously described, a passage or pathway is formed from these subintimal locations to the true lumen of the vessel via methods described herein. In the methods of an embodiment, a guide wire is deflected using a deflecting catheter. Typically, the deflecting catheter is advanced over a proximal end of the guide wire and advanced into the track within the subintimal space. The guide wire and the deflecting catheter are then manipulated so that the guide wire is deflected laterally through the intimal layer or diffuse disease back into the blood vessel lumen at a point distal to the occlusion. Such deflecting catheters also support the guide wire as it is advanced into and/or through the track, i.e. the catheter can enhance the pushability of the guide wire when it is advanced forward through any resisting material.
Alternatively, the guide wire which is initially positioned within the track in the subintimal space may be withdrawn through the deflecting catheter and exchanged for a second wire or other device suitable for penetrating through the intimal layer or diffuse disease back into the blood vessel lumen. The guide wires and/or deflecting catheters and other catheters can be freely exchanged over or through one another in a conventional matter without departing from the methods described herein.
In an embodiment, the physician/user determines when the guide wire and/or deflecting catheter is positioned distal to the total occlusion so that the guide wire can be returned to the blood vessel lumen beyond or distal to any occlusions. Most simply, such position determination can be made by fluoroscopically imaging the blood vessel in a conventional matter.
Alternatively or additionally to such fluoroscopic imaging, intravascular imaging, e.g. intravascular ultrasonic imaging (IVUS), and a variety of optical imaging modalities, such as optical coherence tomography (OCT), are used. For example, an ultrasonic imaging guide wire may be used to initially access the subintimal space and/or may be exchanged for the guide wire which is used to access the subintimal space. Alternatively, the imaging guide wire may be advanced within a lumen of the catheter, or within a cannula to a distal location of the catheter suitable for viewing the surrounding vascular tissue. An imaging guide wire present in the subintimal space may readily detect the presence or absence of occluding material within the blood vessel lumen. When the transition from occluding material to normal arterial tissue is detected, it is known that the position of the guide wire has advanced beyond that of a distal region of the total occlusion.
Alternatively, an imaging system or select imaging components like those described in U.S. Pat. Nos. 5,000,185 and 4,951,677 can be carried on and/or within the catheter system and/or advanced within a lumen of the deflecting catheter to a distal position within the catheter, wherein the surrounding tissue is imaged to determine if the catheter has been advanced beyond a distal region of the total occlusion. The catheter system of an alternative embodiment may house and translate the imaging system or components within the lumen of the cannula itself so that both the cannula and imaging system are independently advanced distally and retracted proximally.
After a passage is formed back from the sub-intimal track into the blood vessel lumen and a wire is in place across the total occlusion, the wire is available for use as a guide wire in positioning interventional and diagnostic catheters across the total occlusion. Most comrnmonly, interventional catheters are positioned across the total occlusion for treating the occlusion. Interventional catheters include, for example, angioplasty balloon catheters, rotational atherectomy catheters, directional atherectomy catheters, and stent-placement catheters, but are not so limited.
Wire deflecting in the catheter system of an embodiment comprises deflecting a cannula from the subintimal space back into the blood vessel lumen and thereafter passing the wire through a path defined/formed by the cannula, typically via a lumen within the cannula. The cannula is advanced over the wire after the wire is disposed within the subintimal space. Deflecting of the cannula in an embodiment comprises advancing a resilient (preformed) curved end of the cannula from a constraining lumen of the catheter into the blood vessel lumen, as described below.
Wire deflecting in alternative embodiments of the catheter system comprises advancing a deflecting catheter over a wire that was previously advanced into the subintimal space. The cannula is subsequently advanced through a lateral opening of the deflecting catheter and penetrated through the intimal layer or diffuse disease to define a path for the guide wire back into the blood vessel lumen.
Wire deflecting in other alternative embodiments comprises advancing a deflecting catheter over a wire which was previously advanced into the subintimal space. The cannula is subsequently advanced through a distal opening of the deflecting catheter and penetrated through the intimal layer or diffuse disease to define a path for the guide wire back into the blood vessel lumen. Steerable and other actively deployed cannulas may also be used.
More usually, however, the wire 10 will advance into the subintimal space within either the medial layer M, or the diffuse disease DD, as shown in
Regardless of the procedure used, however, once the guide wire 10 is advanced to a point that positions the distal tip beyond the total occlusion TO, deflecting catheter 20 is advanced over the wire 10, by coaxial introduction over the proximal end of the wire 10, until it approaches the total occlusion TO, as shown in
The deflection mechanism of an embodiment takes a variety of forms as described below. For example, referring to
The physician/user of the catheter system of an embodiment can assure that the distal tip of the guide wire 10 and the deflecting port 22 (or other deflecting mechanism) of the deflecting catheter 20 are properly positioned beyond the total occlusion TO without being advanced excessively beyond the end of the total occlusion TO. The proper positioning of the deflecting catheter 20 can vary approximately in the range of 0 cm to 2 cm beyond the distal end of the total occlusion TO, but is not so limited. In one embodiment, for example, the deflecting catheter 20 is positioned approximately 0 to 0.5 cm beyond the end of the total occlusion TO.
As described above, such positioning can in some instances be performed using fluoroscopic imaging. For example, in some instances it may be sufficient to provide suitable radiopaque markers on components of the catheter system that include at least one of the guide wire, the cannula, the deflecting mechanism of the catheter, and some combination of any of these components permitting visual positioning of a distal region of the component via fluoroscopy. Fluorescence imaging is described, for example, in U.S. Pat. Nos. 4,718,417 and 5,106,387.
In addition to fluoroscopy, active imaging systems/methods and other imaging modalities that include, but are not limited to, optical coherence tomography (OCT) and Raman spectroscopy can also be used to provide imaging information in a catheter system. The OCT is described, for example, in U.S. Pat. Nos. 5,321,501, 5,459,570, 5,383,467, and 5,439,000. Raman spectroscopy is described, for example, in International Publication Number WO 92/18008.
The catheter system of an embodiment provides for rotational positioning of the deflecting catheter 20. The rotational positioning allows the direction of deflection of the cannula or guide wire to be selective by allowing the physician/user to aim the deflecting mechanism from the subintimal space back toward the arterial or other blood vessel lumen L.
If the catheter is provided with ultrasonic imaging, such imaging can be used for rotationally positioning the distal tip of the catheter. The catheter of an embodiment is rotationally rigid so that rotation of the proximal end allows for positioning of the distal end. Using the detected presence of the blood vessel lumen, the deflecting port 22, and/or other deflecting mechanisms, the guide wire and/or cannula can be rotationally positioned towards the vessel true lumen via ultrasonically identifiable features of these components.
In an alternative embodiment, a rotationally specific fluoroscopic marker can be provided on the catheter 20, or directly on the cannula. The marker is configured so that the rotational direction of the catheter tip or cannula can be determined by observing the two-dimensional image of the marker using fluoroscopic imaging.
Devices described herein for use in crossing vascular occlusions include catheter systems, also referred to as wire deflection or wire deflecting systems. The wire deflection systems of an embodiment generally comprise a wire deflecting catheter that includes a catheter body and a deflecting cannula. The catheter body includes a proximal end, a distal end, and at least one lumen extending through at least a distal portion of the catheter body. In one embodiment, the lumen communicates with at least one of a distal port and/or a lateral port in at least one of a distal section, distal region, or end zone of the catheter. In various alternative embodiments, the lumen communicates with one or more distal ports and/or one or more lateral ports.
The cannula of an embodiment also includes a proximal end, a distal end, and at least one lumen extending through a distal portion of the cannula. The distal portion of the cannula may include a pre-formed resilient curve, as described below. The cannula is slidably disposed within the lumen of the catheter body but is not so limited. Upon full proximal retraction of the cannula within the catheter body lumen, the distal section of the catheter can be configured to assume at least one of a straight configuration and a curved configuration. The cannula can be deployed through at least one of a lateral port and an end port as appropriate to a procedure to establish a pathway through the subintimal tissue/diffuse disease according to the methods described herein.
The choice of materials and fabrication methods for the catheter shaft and/or the cannula determine the resultant shape of the distal section of the catheter when the cannula is fully retracted. Either the straight or curved configuration of the distal catheter shaft may apply to two embodiments of the catheter as follows. A first embodiment of the catheter includes both a distal and lateral port, and full advancement of the cannula selectively deploys the pre-shaped cannula from the lateral port. A second embodiment of the catheter includes a single distal port, and full advancement of the cannula deploys the pre-shaped cannula from the distal port. Various alternative embodiments include different combinations of lateral ports, distal ports, and cannula deployment options.
The catheter system of an embodiment further comprises a wire configured to pass through the cannula lumen. The wire may be a conventional guide wire, a wire having a sharpened distal tip extended particularly for penetrating the intimal layer of the blood vessel wall and/or diffuse disease of the blood vessel, and/or other wires known in the art. Alternatively, the wire may include passive and/or active visualization or imaging means.
Regarding passive visualization or imaging systems, the catheter body of an embodiment includes one or more fluoroscopically visible markers near the distal end. The markers are configured to permit visual determination of the rotational orientation of the distal end of the catheter body when viewed in a two-dimensional fluoroscopic image. The catheter body can be reinforced to enhance torsional rigidity, and can further comprise a distal nose cone wherein the distal and/or lateral openings may be defined within the nose cone. The distal end of the cannula of an embodiment is pre-formed in a smooth curve which may extend over an arc approximately in the range of 15 to 135 degrees, but is not limited to this range. The pre-formed curve may have a radius approximately in the range of 0.5 millimeters (mm) to 15 mm, but is not limited to this range.
A number of specific embodiments of the catheter system are described below, wherein use of the catheter system is generally described above with reference to
The cannula 46 of an embodiment is constructed from a composite of braided stainless steel wire that is laminated with polymers such as nylons, urethanes, polyimides or polycarbonates, but is not so limited and can be formed from other materials as appropriate to the medical applications. The distal end of the cannula 46 can be terminated in an angled cut of the material, forming a needle-like tip, or terminated with a sharpened, fluoroscopic hollow metallic tip formed to include Platinum-Iridium, for example. Alternatively, the cannula 46 can be fabricated from a uniform material such as nitinol (nickel-titanium), and terminated in a needle type tip via sharpening into an appropriate shape.
To further increase torque control of the cannula 46, especially in high tortuosity applications, stainless steel wire or other suitable filaments are braided onto the cannula 46 of an embodiment. The braided cannula 46 can also be laminated with appropriate polymers (nylons, polyurethanes) to produce a smooth exterior surface of the cannula shaft. Further, the polymer of an embodiment is coated with a hydrophilic agent to decrease frictional effects as the cannula 46 is translated within the catheter shaft. A resilient curve may be set into the distal section of the cannula 46 via heat setting methods for these materials, such heat setting methods known in the art. Materials and methods of cannula construction also allow some degree of radiopacity, i.e. ability to produce an image under fluoroscopy.
Upon full extension of the cannula 46 from the catheter shaft, the cannula 46 is unconstrained, allowing the as-manufactured curved shape of the distal cannula 46. Upon full retraction of the cannula 46 into the catheter shaft, two configurations are possible. A first configuration is one in which the distal end of the catheter assumes a curved shape. The degree of the curve can range from the as-manufactured curve of the cannula to something approaching a straight configuration. A second configuration is one in which the catheter assumes a straight configuration.
Each of these configurations is possible through the selection of materials used to construct both the distal section of the catheter shaft, and the distal section of the cannula. To achieve the first or curved configuration, the material used to construct the cannula is more robust (for example, nitinol), and the material used to construct the distal section of the catheter shaft is comparitively less robust (for example, a braided shaft laminated with low durometer urethane). This combination allows the catheter shaft to conform more to the shape of the cannula as the cannula is retracted into the catheter shaft. These fabrications and fabrication materials are provided as examples only, as many others allow the distal catheter shaft to follow the shape of the cannula.
The second or straight configuration is achieved by fabricating a less robust or “softer” cannula with wire braid laminated with a medium durometer nylon such as 55D Pebax, and fabricating the catheter shaft with wire braid laminated with polyamide. The softer design of the cannula shaft allows the cannula to conform to the straight configuration of the catheter shaft as the cannula is retracted into the catheter shaft. Alternatively, the distal end of the catheter shaft may be fabricated with an integral section of stainless steel hypotube, or other non-flexible material. This section of hypotube performs in similar fashion to maintain the straight configuration of the distal catheter shaft as the cannula is retracted. Again, these fabrications and fabrication materials are provided as examples only, as many others allow the distal region of the cannula, upon retraction, to conform to the straight configuration of the distal region of the catheter shaft.
The three catheter systems 30, 40, and 50 presented with reference to
The distal catheter terminations of the catheter system embodiments described herein can be fabricated as a continuation of the catheter shaft polymers, which have been formed or molded into the configurations shown. Alternatively, the distal terminations include a separate nosecone component attached to the terminal end of the catheter shaft. Regarding the attachment of the nosecone, the catheter shaft can be attached to the nosecone by lamination of the shaft polymer onto features at the proximal end of the nosecone, but is not so limited.
Alternative embodiments of the catheter systems described herein, however, include composite terminations that provide strong flexible connections of the nosecone to the catheter shaft.
The composite termination 1600 provides a very strong, flexible connection of the nosecone 1604 to the catheter shaft 1602. One challenge of terminating the outer polymer layer 1618 to the internal 1610 and external 1612 rings is that if both the shaft polymer 1618 and ring termination are bluntly terminated to each other, the distinct boundary existing betweeri the two materials may tend to delaminate during operation of the catheter system due to bending stresses. The termination of an embodiment alleviates this issue through the inclusion of an internal taper 1620 in the external ring 1612 at the terminal end of the catheter shaft. This taper 1620 of the external ring 1612 allows a small continuous taper of polymer 1618 to be produced underneath the external ring 1612 to afford stress relief upon bending of the catheter shaft 1602 at this boundary location. This taper 1620 prevents delamination of the polymer 1618 from the internal 1610 and external 1612 rings.
Referring to
The deflecting catheter 100, in operation, laterally deflects the distal tip of the cannula 114 through a lateral opening 122 in the deflector housing 110. The deflector housing 110 also includes a distal port 124 to permit introduction of the catheter 100 over the proximal end of a guide wire GW, as shown in
With reference to
Keying of components of the catheter system, as described above, can be accomplished with a variety of techniques at both the proximal and distal end of the catheter. Keying at the proximal end of the catheter 100 can be achieved in a variety of ways.
Keying at the distal end of the catheter 100 can also be achieved in a number of ways.
In use, and with reference to
When the distal end of the catheter system assumes a straight configuration upon retraction of the cannula into the catheter shaft, keying and fluoroscopic marker options are numerous. As described with reference to
In an alternative embodiment, the features of the fluoroscopic marker 120 are directly incorporated into the catheter nosecone or distal termination of the catheter shaft. Keying of the catheter shaft and cannula is also incorporated as described above.
In another alternative embodiment, the cannula can include a similar marking system 120 as the shaft. Since the cannula marker directly indicates deployment direction of the cannula, keying is not used between catheter shaft and cannula, nor is directional marking on the catheter shaft, but the embodiment is not so limited.
Yet another alternative embodiment includes a combination of catheter shaft marker and cannula marker. In this embodiment, since the cannula includes directional (deployment) marking, the catheter marker is not directional, and it signifies the location of the catheter distal end. A simple fluoroscopic nosecone or ring suffices for this type of marking.
When the distal end of the catheter system assumes a curved configuration upon retraction of the cannula into the catheter shaft, there are also numerous keying and fluoroscopic marker options. In an embodiment, non-directional fluoroscopic markers as described herein are used on either the distal catheter shaft or the distal cannula. Keying is not included since the curve of the cannula in the retracted position automatically angles the distal portion of the catheter shaft in the direction of the cannula deployment.
In an alternative embodiment a directional marker 120 is included on/in the cannula to indicate deployment direction, and works in concert with the directional curve at the distal end of the catheter shaft. Keying is not included in this embodiment (
Another alternative embodiment includes a directional marker on the catheter for use in concert with the directional curve at the distal end of the catheter shaft. Keying is included in this embodiment, as described above.
Yet another alternative embodiment includes one or more combinations of the marking schemes described herein. In general, whenever directional marking is used on the catheter shaft, keying is used to align the catheter shaft marker to the cannula curve deployment direction.
In addition to the numerous passive visualization systems described above, various embodiments of the catheter systems described herein can include active on-board visualization systems and methods. One example of an on-board visualization system is described as a rotational ultrasound system in U.S. Pat. Nos. 4,951,677 and 5,000,185, but the on-board visualization systems used in the catheter systems described herein are not so limited.
An embodiment of the catheter system, however, provides ultrasonic or other imaging at or near the total occlusion to assist the physician/user in positioning the catheter system. In one embodiment, guide wire includes at least one ultrasonic imaging component or device to detect the presence and absence of the occluding material as the wire is advanced past the total occlusion. In an alternative embodiment, the deflecting catheter includes such ultrasonic imaging, e.g. in the form of a phased array located near the distal tip of the deflecting catheter. U.S. Pat. Nos. 4,917,097 and 5,368,037 describe a phased array system for use in a deflecting catheter, but the embodiment is not limited to these visualization systems.
The visualization system of an embodiment includes ultrasonic imaging guide wires, but is not so limited. For example, U.S. Pat. No. 5,095,911 describes an ultrasonic imaging guide wire, but the embodiment is not limited to this particular imaging-guide wire. As yet another alternative, an imaging guide wire can be advanced to the region of the total occlusion in a direction opposite to that of the guide wire and catheter. In this way the imaging guide wire need not advance through the total occlusion, but could still detect advancement of the catheter and/or guide wire, particularly if ultrasonically opaque components are provided on the catheter and/or the guide wire. In still another alternative, an ultrasonic imaging catheter or guide wire is positioned in a vein adjacent to the arterial occlusion site, allowing imaging of the entire occluded region while the guide wire is advanced through the occluded region.
Generally, an ultrasound visualization system can be used under at least two methods. Under a first method, the rotational ultrasound catheter system, or its functional components are advanced first within a catheter lumen to a distal region of the catheter shaft suitable for imaging the surrounding tissue. As an example, the ultrasound components can be advanced beyond a distal end of the catheter.
As another example, the ultrasound components can be to a distal region of the catheter shaft while remaining housed in the catheter.
Following advancement of the ultrasound system to a location appropriate for imaging, the catheter is aligned to the vessel true lumen under a number of methods. Under a first method of catheter alignment, features at the distal end of the catheter, such as those that are machined into a nosecone as the viewing window, are identified via ultrasound imaging, and used to align a lateral or distal port to the true lumen. The ultrasound system is subsequently extracted and a keyed cannula system is advanced within the catheter lumen to exit in the direction of the viewing window and true lumen.
Under a second method of catheter alignment, ultrasound systems/components similar to those described in the first method of catheter alignment are used to align a catheter port with the vessel true lumen. However, instead of relying on a keying mechanism to align the cannula with the vessel true lumen (as described above), use is made of the ultrasonic components of the catheter as fluoroscopic alignment features. In this way, once the catheter port is aligned to the vessel true lumen using the ultrasonic components, the same features may provide fluoroscopic alignment, indicating direction of the vessel true lumen. A cannula with a directional fluoroscopic marker is then advanced within the catheter and brought into fluoroscopic alignment with the catheter marker, providing deployment guidance towards the vessel true lumen.
A second method under which ultrasound visualization systems are used includes advancing the rotational ultrasound catheter system or its functional components within the cannula.
Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in a sense of “including, but not limited to.” Words using the singular or plural number also include the plural or singular number respectively. Additionally, the terms “herein,” “hereunder,” “above,” “below,” and terms of similar import, when used in this application, refer to this application as a whole and not to any particular portion of this application. When the word “or” is used in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list and any combination of the items in the list.
The above description of illustrated embodiments of the catheter system is not intended to be exhaustive or to limit the catheter system to the precise form disclosed. While specific embodiments of, and examples for, the catheter system are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the catheter system, as those skilled in the relevant art will recognize. The teachings of the catheter system provided herein can be applied to other medical devices and systems, not only for the catheter systems described above.
The elements and acts of the various embodiments described above can be combined to provide further embodiments of the catheter system. These and other changes can be made to the catheter system in view of the above detailed description.
All of the above references and United States patents and patent applications are incorporated herein by reference. Aspects of the catheter system can be modified, if necessary, to employ the systems, functions and concepts of the various patents and applications described above to provide yet further embodiments of the system.
In general, in the following claims, the terms used should not be construed to limit the catheter system to the specific embodiments disclosed in the specification and the claims, but should be construed to include all catheter systems and medical devices that operate under the claims to cross vascular occlusions. Accordingly, the catheter system is not limited by the disclosure, but instead the scope of the catheter system is to be determined entirely by the claims.
While certain aspects of the catheter system are presented below in certain claim forms, the inventors contemplate the various aspects of the catheter system in any number of claim forms. Accordingly, the inventors reserve the right to add additional claims after filing the application to pursue such additional claim forms for other aspects of the catheter system.
This application is a continuation-in-part application of U.S. patent application Ser. No. 10/308,568, filed Dec. 3, 2002, which is a continuation of U.S. patent application Ser. No. 09/765,777, filed Jan. 19, 2001, now U.S. Pat. No. 6,511,458, which is a continuation of U.S. patent application Ser. No. 09/440,308, filed Nov. 17, 1999, now U.S. Pat. No. 6,235,000, and which is a division of U.S. patent application Ser. No. 09/006,563, filed Jan. 13, 1998, now U.S. Pat. No. 6,231,546.
Number | Date | Country | |
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Parent | 09006563 | Jan 1998 | US |
Child | 09440308 | Nov 1999 | US |
Number | Date | Country | |
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Parent | 09765777 | Jan 2001 | US |
Child | 10308568 | Dec 2002 | US |
Parent | 09440308 | Nov 1999 | US |
Child | 09765777 | Jan 2001 | US |
Number | Date | Country | |
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Parent | 10308568 | Dec 2002 | US |
Child | 10823416 | Apr 2004 | US |