The present invention is directed generally to catheters and retrieval methods. More particularly, the present invention is directed to dual-lumen retrieval catheters and methods of retrieving deployed medical devices such as, for example, embolic protection devices.
Transcatheter procedures are employed in increasing numbers for opening stenosed or occluded blood vessels in patients caused by deposits of plaque or other materials on the walls of the blood vessels. Such minimally invasive procedures have proven to be advantageous compared to traditional surgical procedures, such as open heart surgery. Stenosis in arteries and other blood vessels can be treated by permanently or temporarily introducing a stent into the stenosed region to open the lumen of the vessel.
However, embolic material may be released into the blood stream during implantation of a stent or another prosthetic device, placing the patient at great risk. Embolic material formed of calcium deposits, intimal debris, pieces of artheromatous plaque and/or thrombi has the potential of migrating downstream and causing distal tissue damage, for example stroke or myocardial infarction (see Topol, E. J. and Yadav, J. S., “Recognition of the Importance of Embolization in Athereosclerotic Vascular Disease”, Circulation 2000, 101:570). Embolic material which can potentially damage the distal tissue is often released during vascular intervention procedures, such as stenting of an artheromatous region.
To alleviate this problem, an embolic filter, or other type of embolic protection device (EPD), may be advanced to a site distal to the treatment site to filter and capture undesired embolic material from the blood. The filter is typically inserted over or together with a guidewire using a delivery catheter. Following the treatment procedure, the filter is collapsed and removed from the body over the guidewire or together with the guidewire. Additional treatment devices, such as balloons and stents, can be inserted and/or removed via the same guidewire.
During some procedures, after treatment with a balloon and/or stent is completed, the surgeon may discover another lesion or stenosis distal of the original treatment site or discover a vessel dissection resulting from the immediately preceding procedure. In such cases, the surgeon must remove the guidewire with the collapsed filter and then re-deploy a new guidewire for treatment of the second site. This procedure of re-inserting a secondary guidewire adds significantly to the patient's treatment time since deployment of a guidewire is very time consuming. Additionally, re-inserting a secondary guidewire also introduces modest risk of plaque embolization while the guidewire is being position at the diseased artery.
Referring to
Thus, if a second lesion 17 is subsequently discovered, the surgeon would need to retrieve the EPD 10 together with the guidewire 12, and subsequently replace the guidewire 12 with a new one. For such cases, it would be desired to provide a retrieval catheter that permits delivery of a secondary guidewire while the primary guidewire 12 and EPD 10 are still deployed. In particular, it would be desirable if the retrieval catheter could also serve to introduce a secondary guidewire, prior to recovery of the primary guidewire and EPD. Thus, such an improved retrieval catheter would perform the dual functions of delivery of a secondary guidewire while retrieving a previously-deployed EPD system.
Retrieving an EPD has posed challenges because of apparently contradictory requirements for the design of the retrieval catheter. On one hand, the collecting tube with which the filter is retrieved needs to have a large inside diameter in order to capture the filter easily and avoid squeezing out the material caught in the filter during the procedure; on the other hand, the size of the collecting tube is limited by the size of the guiding catheter size, the stent size through which the collecting tube must navigate, trauma to vessel, etc.
A large open-tube design of the collecting tube can be traumatic to the blood vessel. To alleviate trauma and facilitate navigation, the distal part of, for example, balloon catheters has a tapered soft tip which tapers all the way from the maximal tube diameter to the guidewire diameter. In this way, the catheter does not “dig” into the vessel wall, especially in tortuous vessels or get caught when traversing a stent, where struts may protrude toward the center of the blood vessel.
Several manufacturers have attempted to solve this problem by tapering the distal end of the collecting tube used for retrieval which, however, tends to make retrieval of the full filter more difficult and risks discharging particles back into the blood stream. In addition, the collecting tube and catheter need to be built from a sufficiently rigid material to prevent collapse when the filter is pulled into the tube, which makes it impossible to use a very flexible tube which will track softly through the blood vessels.
The retrieval catheters and retrieval methods of the present disclosure solve one or more of the problems set forth above.
According to one aspect of the invention, a catheter for retrieving a medical device deployed in a body lumen includes a first guidewire lumen extending through a distal shaft portion of the retrieval catheter from a first proximal guidewire port to a first distal guidewire port, and a second guidewire lumen extending through the distal shaft portion of the retrieval catheter from a second proximal guidewire port to a second distal guidewire port. The first guidewire lumen has a distal end portion dimensioned to recapture the medical device secured on a first guidewire distal of the distal end portion. The first guidewire passes through the first guidewire lumen. The second guidewire lumen is radially offset from the first guidewire lumen and receives a second guidewire operable separately from the first guidewire for advancement past the distal end portion following recapture of the medical device.
According to another aspect of the invention, a method of retrieving an embolic protection device deployed in a body lumen at a location distal to a first interventional procedure site and secured to a first guidewire includes the steps of advancing a retrieval catheter along the first guidewire to a location proximal of the embolic protection device, wherein the retrieval catheter has a first guidewire lumen extending through a distal shaft portion of the retrieval catheter from a first proximal guidewire port to a first distal guidewire port. The first guidewire lumen has a distal end portion dimensioned to recapture the embolic protection in a collapsed state, and the first guidewire passes through the first guidewire lumen. The retrieval catheter further has a second guidewire lumen extending through the distal shaft portion of the retrieval catheter from a second proximal guidewire port to a second distal guidewire port. The second guidewire lumen is radially offset from the first guidewire lumen and receives a second guidewire operable separately from the first guidewire. The method includes the additional steps of recapturing the collapsed embolic protection device into the first guidewire lumen of the retrieval catheter, advancing the second guidewire through the second guidewire lumen of the retrieval catheter to a second interventional procedure site, and withdrawing the retrieval catheter with the embolic protection device and the first guidewire, while leaving the second guidewire in place.
According to one embodiment, the dual-lumen retrieval catheter may include a tipped member having a conical shape with a greatest outside diameter sized to be slidably received in the distal end portion of the first guidewire lumen and a center opening through which the first guidewire passes. The tip of the tipped member may protrude distally from the distal end portion when the retrieval catheter is advanced distally in the body lumen towards the medical device to prevent trauma to the vessel.
According to yet another aspect of the invention, a catheter for retrieving a medical device deployed in a body lumen includes a guidewire lumen extending through a distal shaft portion of the retrieval catheter from a first proximal guidewire port to a first distal guidewire port. The guidewire lumen has a distal end portion dimensioned to recapture the medical device secured on a guidewire distal of the distal end portion. The guidewire passes through the guidewire lumen. The catheter further includes a tipped member having a conical shape with a greatest outside diameter sized to be slidably received in the distal end portion of the guidewire lumen and a center opening through which the guidewire passes. The tip of the tipped member protrudes distally from the distal end portion when the retrieval catheter is advanced distally in the body lumen towards the medical device.
According to still another aspect of the invention, a method of retrieving an embolic protection device deployed in a body lumen and secured to a guidewire includes the steps of advancing a retrieval catheter along the guidewire to a location proximal of the embolic protection device. The retrieval catheter has a guidewire lumen extending through a distal shaft portion of the retrieval catheter from a proximal guidewire port to a distal guidewire port. The guidewire lumen has a distal end portion dimensioned to recapture the embolic protection device in a collapsed state. A tipped member having a conical shape is slidably received in a distal end portion of the guidewire lumen, with the pointed end protruding distally from the distal end portion. The guidewire passes longitudinally through the tipped member. The method includes the additional steps of collapsing the embolic protection device, and pulling the collapsed embolic protection device proximally into the guidewire lumen of the retrieval catheter.
In one embodiment, a pulling wire may be secured to the tipped member, for example by a material connection or a force-transmitting connection, for defining a longitudinal position of the tipped member inside the receiving guidewire lumen. The tipped member may frictionally engage with the distal end portion of the receiving guidewire lumen.
In one embodiment, a proximal actuator may be provided which has a distal section attached to a proximal shaft portion of the retrieval catheter, and a proximal section movable longitudinally with respect to the distal section and secured to the pulling wire. The tipped member is longitudinally displaced inside the distal end portion of the first guidewire lumen by moving the proximal section relative to the distal section.
The retrieval catheter may be configured for rapid exchange.
These and other features and advantages of the present invention will become more readily appreciated from the detailed description of the invention that follows.
The following figures depict certain illustrative embodiments of the invention in which like reference numerals refer to like elements. These depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way.
Various aspects of exemplary retrieval catheters and methods are disclosed herein which may efficiently and effectively enable a therapeutic procedure to be performed in a blood vessel at an interventional procedure site, for example, stenosis site due to plaque. The exemplary catheters and methods may be part of a therapeutic system and method configured to occlude the blood vessel at a location relative to the interventional procedure site, prevent the flow of blood past the occlusion, and enable the capture and recovery of embolic material which may be released into the blood vessel during the interventional procedure.
The retrieval catheters and methods are illustrated and described herein by way of example only and not by way of limitation. While the exemplary retrieval catheters and methods are described in detail as applied to the carotid arteries of the patient, those skilled in the art will appreciate that they can also be used in other body lumens as well, such as the coronary arteries, renal arteries, saphenous veins, and other peripheral arteries. Additionally, the exemplary retrieval catheters and methods can be utilized when performing any one of a number of interventional procedures, such as stenting, balloon angioplasty, laser angioplasty, or atherectomy.
Referring again back to
The primary guidewire 12 may then be controllably steered to the site 13 of a lesion or stenosis in a body lumen, for example, a blood vessel, following introduction through a pre-deployed guide catheter. Primary guidewire 12 is manipulated the interventional vascular practitioner into the selected left or right common carotid artery, as appropriate. Primary guidewire 12 is then steered into an appropriately selected internal or external carotid artery, in accordance with the location of the procedure site 13. Ultimately, the distal tip of primary guidewire 12 is positioned at a location slightly distal of the interventional procedure site 13. Primary guidewire 12 can then be used to deliver an EPD 10, such as an embolic protection filter, to a location slightly distal of the interventional procedure site 13. EPD 10 may preferably be delivered to the treatment site using a rapid exchange embolic protection device delivery catheter (not shown). As previously discussed, the embolic protection device 10 may be configured to lock onto the guidewire 12, for example, as described in U.S. patent application Ser. Nos. 11/873,882 and 11/873,893.
The intravascular therapeutic treatment procedure may further include insertion of a balloon dilatation catheter followed by a stent delivery catheter, both catheters utilizing a rapid exchange configuration for ease of access to the site of the stenosis or lesion to be treated. Since all of the aforementioned catheters preferably utilize the rapid exchange configuration, each catheter can easily be substituted and introduced over a standard length interventional guidewire. The balloon and stent catheters are delivered over the guidewire to a position just proximal of the deployed embolic protection device. The balloon and stent may be deployed to treat the stenosis or lesion, as is known by persons skilled in the art. As previously mentioned, if the surgeon notices a second treatment site distal to the first site after the first site has been treated, a dual-lumen retrieval device in accordance with the disclosure may then be delivered to capture the embolic protection device, assist in delivery of a secondary guidewire, and remove the primary guidewire originally introduced, together with the re-captured embolic protection device, from the body lumen.
A distal portion of an exemplary embodiment of a dual-lumen retrieval catheter 22 is shown in
In operation, the retrieval catheter 22 may be delivered to the intravascular site where the embolic protection device 10 is deployed. The first lumen 24 of the catheter 22 receives a collapsing or collapsed EPD 10. As previously described, the embolic protection device 10 may be retrieved with the primary guidewire 18, upon which it is locked. Removal of the catheter 22 with EPD 10 leaves the secondary guidewire 27 in a therapeutic position associated with the second lesion site 17, as shown in
Referring now to
To enable rapid exchange, the distal shaft portion 24b includes a first proximal guidewire port 42, a first distal guidewire port 24, and a second distal guidewire port 26. The first proximal guidewire port 42 may be spaced from the proximal end 40 of the catheter 22. The first guidewire lumen 24 may extend through the distal shaft portion 24b from the first proximal guidewire port 42 to the first distal guidewire port 24. The first guidewire lumen 24 may have a distal end portion (not shown), which is similar to the collecting tube 55 shown in
The primary guidewire 18, which extends distally from the distal shaft portion 24b, exits a proximal end 24a of the distal shaft portion at a rapid exchange port 42 and extends proximally parallel with the proximal shaft portion 24a and through the guide catheter 41 and a hub 45 as it exits the patient's body.
A secondary guidewire 27 can be introduced through the catheter 22 via the proximal shaft portion 24a and extends from the second lumen 26 of the distal shaft portion 24b to enter the patient's blood vessel distal of the catheter 22 (
According to some aspects, as shown in
Another retrieval catheter and retrieval method is shown in and described with reference to
The first lumen 155 may be configured to collect a deployed EPD 10 (not shown in
As evident from
The guidewire 18 together with the proximal handle section 87 is then pulled proximally away from the stationary distal handle section 88, as shown in
It will be appreciated by those skilled in the art that the soft-tipped retrieval catheter depicted in
Those of skill in the art will appreciate that the soft tip 72 can also be frictionally held in place inside the collection tube 74, obviating the need for a separate pull wire. Retraction of the EPD 85 will then also push the soft tip 72 back into the lumen of the retrieval catheter. However, this process may distort the shape of the soft tip 72, requiring a harder material for the soft tip 72 which could then again disadvantageously induce trauma in the vessel. In addition, the soft tip 72 would not be securely held captive in the collection tube 74 during advancement through the vessel and may become dislodged from its position inside the collection tube 74, though still being held by the guidewire extending through the soft tip 72.
It will be apparent to those skilled in the art that various modifications and variations can be made to the retrieval catheters and methods of the present invention without departing from the scope of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only.
This application claims priority to U.S. Provisional Application Ser. No. 61/042,131, filed Apr. 3, 2008, the entire content of which is incorporated herein by reference.
Number | Date | Country | |
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61042131 | Apr 2008 | US |