|Publication number||US20090171431 A1|
|Application number||US 12/396,350|
|Publication date||Jul 2, 2009|
|Filing date||Mar 2, 2009|
|Priority date||Mar 3, 2003|
|Also published as||EP1605866A2, EP1605866A4, US8409268, US8840658, US20040220655, US20090171445, US20100211155, WO2004078065A2, WO2004078065A3|
|Publication number||12396350, 396350, US 2009/0171431 A1, US 2009/171431 A1, US 20090171431 A1, US 20090171431A1, US 2009171431 A1, US 2009171431A1, US-A1-20090171431, US-A1-2009171431, US2009/0171431A1, US2009/171431A1, US20090171431 A1, US20090171431A1, US2009171431 A1, US2009171431A1|
|Inventors||William Swanson, Richard Cornelius, Robert S. Schwartz|
|Original Assignee||William Swanson, Richard Cornelius, Schwartz Robert S|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (8), Classifications (21)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application claims priority to U.S. patent application Ser. No. 10/792,110 filed Mar. 2, 2004 entitled Electrical Conduction Block Implant Device which in turn claims priority to U.S. Provisional Application Ser. No. 60/451,865 filed Mar. 3, 2003 entitled Implantable Device to Create Ostial Electrical Block in the Pulmonary Veins for Treatment of Atrial Fibrillation and to U.S. Provisional Application Ser. No. 60/451,864 filed Mar. 3, 2003 entitled Implantable Ring to Create Electrical Block in Pulmonary Vein Ostium for Treating Atrial Fibrillation, the entire contents of all of which being hereby incorporated by reference.
Pumping of the human heart is caused by precisely timed cycles of compartmental contractions of the heart muscle which lead to an efficient movement of blood into the heart and out to the various bodily organs. These precisely timed cycles are controlled and directed by electrical signals that are conducted through the cardiac tissue and can be referred to as pacing signals.
The sinoatrial node (SA node) is the heart's natural pacemaker, located in the upper wall of the right atrium. The SA node spontaneously contracts and generates nerve impulses that travel throughout the heart wall causing both the left and right atriums to sequentially contract according to a normal rhythm for pumping of the heart. These electrical impulses continue to the atrioventricular node (AV node) and down a group of specialized fibers called the His-Purkinje system to the ventricles. This electrical pathway must be exactly followed for proper functioning of the heart.
When the normal sequence of electrical impulses changes or is disrupted, the heart rhythm often becomes abnormal. This condition is generally referred to as an arrhythmia and can take the form of such arrhythmias as tachycardias (abnormally fast heart rate), bradycardias (abnormally slow heart rate) and fibrillations (irregular heart beats).
Of these abnormal heart rhythms, fibrillations, and particularly atrial fibrillations, are gaining more and more attention by clinicians and health workers. Atrial fibrillation develops when a disturbance in the electrical signals causes the two upper atrial chambers of the heart to quiver instead of pump properly. When this happens, the heart is unable to discharge all of the blood from the heart's chambers thus creating a situation where the blood may begin to pool and even clot inside the atrium. Such clotting can be very serious insofar as the clot can break away from the atrial chamber and block an artery in the brain, and thereby cause a stroke in the individual.
A variety of treatments have been developed over the years to treat atrial fibrillation, namely, treatments to either mitigate or eliminate electrical conduction pathways that lead to the arrhythmia. Those treatments include medication, electrical stimulation, surgical procedures and ablation techniques. In this regard, typical pharmacological treatments have been previously disclosed in U.S. Pat. No. 4,673,563 to Berne et al.; U.S. Pat. No. 4,569,801 to Molloy et al.; and also by Hindricks, et al. in “Current Management of Arrhythmias” (1991), the contents of which are herein incorporated by reference.
Surgical procedures, such as the “maze procedure”, have also been proposed as alternative treatment methods. The “maze” procedure attempts to relieve atrial arrhythmia by restoring effective atrial systole and sinus node control through a series of incisions.
The Maze procedure is an open heart surgical procedure in which incisions are made in both the left and right atrial walls which surround the pulmonary vein ostia and which leave a “maze-like” pathway between the sinoatrial node and the atrioventricular node. The incisions are sewn back together but result in a scar line which acts as a barrier to electrical conduction.
Although the “maze” procedure has its advantages, in practice it can be a complicated and a particularly risky procedure to perform since the surgeon is making numerous physical incisions in the heart tissue. Due in part to the risky nature of the Maze procedure, alternative, catheter-based treatments have been advanced. Many of these catheter devices create the desired electrical block by way of ablation devices designed to burn lesions into the target tissue. Examples of these devices can be seen in U.S. patents: U.S. Pat. No. 6,254,599 to Lesh; U.S. Pat. No. 5,617,854 to Munsif; U.S. Pat. No. 4,898,591 to Jang et al.; U.S. Pat. No. 5,487,385 to Avitall; and U.S. Pat. No. 5,582,609 to Swanson, all incorporated herein by reference.
Although ablation catheter procedures remain less invasive than previous surgical methods like the “maze” procedure, they nevertheless retain a significant element of risk. For example, ablation procedures often utilize high power RF energy or ultrasonic energy, which may adequately create electrical block, but their inherent destructive nature allows for the possibility of unintended damage to the target tissue or nearby areas.
Further, it is often difficult to achieve certainty as to whether the appropriate amount of ablation has been performed uniformly around the perimeter of the target site or if the desired site is even being ablated.
Ablation procedures have also seen an occurrence of stenosis in the pulmonary veins as a response to the ablation. This is a serious complication and as a result, many doctors try to limit their treatment to the ostium of the pulmonary veins to minimize the risk of creating a stenosis in the pulmonary veins.
Finally, various implant devices have also been proposed. Examples of such proposed devices are disclosed in co-pending U.S. application Ser. No. 10/192,402 filed Jul. 8, 2002 entitled Anti-Arrhythmia Devices and Methods of Use, the entire contents of which is hereby incorporated by reference.
The solutions in the prior art, however, are not believed to be entirely effective in many cases, and indeed may result in actually inducing long term arrhythmias and inefficacy.
As a result, what is needed are minimally invasive techniques for creating electrical block in the pulmonary veins which reduce the complication risk of previously known procedures, while increasing effectiveness and speed of the procedure to create electrical block.
It is an object of the present invention to provide a minimally invasive device and technique for deploying such a device that safely and effectively blocks aberrant electrical signals at or near the ostium of the pulmonary veins.
It is a further object of the present invention to provide a minimally invasive electrical block device that is easy to deploy and has a low risk of complication.
It is yet a further object of the present invention to provide an electrical block device that consistently creates a circumferential scar line around the pulmonary ostium to completely block aberrant electrical signals causing atrial fibrillation.
The present invention achieves these objects by providing an electrical block implant sized and shaped for securement at the perimeter of the pulmonary ostium of the left atrium.
The ostium of the pulmonary veins has a highly variable geometry from one patient to another and this presents difficulty in reliably treating atrial arrhythmias using previous methods. That is, the variable geometry has in the past made it difficult to reliably create a continuous line of electrical block around the perimeter of the ostium in each and every patient.
In illustration of this point,
In addition to these geometric variations, the ostia may differ in diameter and location of the side branches from patient to patient. For example, typical target site diameters may range anywhere from about 10 to 30 mm. This provides a considerable challenge for any consistently performed electrical block procedure for the treatment of an atrial arrhythmia.
To address this problem, the present invention provides an electrical block device that is implantable and anchorable within the pulmonary veins and/or left atrium of many different geometries. That is, the present invention presents a device and method that is adaptable for use in conducting substantially uniform treatment of a wide segment of the human population.
And generally speaking, the present invention performs this function in a way that consistently circumferentially blocks aberrant electrical signals through its presence in the ostium of the pulmonary veins. The electrical block device in accordance with the present invention may act through the mere presence in the ostium and/or through controlled scarring caused by the device.
The controlled scarring can be created by a number of possible mechanisms. One possible mechanism is to have the device press against the tissue with enough force to cause pressure necrosis. As the tissue necroses, the device slowly migrates through the wall and scar tissue forms behind the device as it slowly migrates through the tissue wall. With this mechanism, it is possible that the device can ultimately migrate through the entire tissue wall leaving a line of scar through the entire wall thickness.
In another possible mechanism, the device can press against the tissue causing tension in the tissue wall. This tension in the tissue can cause fibrosis in the wall without having the device actually pass through the wall as was described for the pressure necrosis mechanism above.
Another possible mechanism is to have the presence of the device cause necrosis in the tissue as a result of a reaction to the material of the device or a material attached to the device. It is also possible to use combinations of these mechanisms.
The controlled scarring is believed to disrupt the cellular structure of cardiac tissue that is present in or on the pulmonary vein wall or the atrial wall outside the ostia and thereby prevent such cardiac tissue from propagating aberrant electrical signals that cause the atrial arrhythmias. While this invention describes use for electrical isolation of pulmonary veins, these same devices and methods can also be applied to other sites such as the superior vena cava or the coronary sinus.
Electrical Block Device with Anchoring Clip
A first preferred embodiment of the present invention is depicted in
With reference to
The expandable ring 102 expands from its undeployed configuration by as much as 10 times or more beyond its size in a compressed state so as to press around the perimeter of the ostium. This expansile force assists in securing the expandable ring 102 in proper position.
In addition to its function of spatially positioning the device 100 in the ostial space, the expandable ring 102 also serves as the primary mechanism of creating the desired electrical conduction block. The expandable ring 102 can cause this electrical block either by inducing controlled scarring of the tissue contacted by the ring 102 or by the mere presence of the ring itself, or by a combination of the two. And as to the use of controlled scarring, any controlled method of scarring may be used, such as chemical coatings on the ring 102 that cause scarring, physical scarring devices mounted on the ring 102, or even mere physical expanding pressure from the ring 102 against the tissue.
Preferably, the wire that forms the electrical block device 100 is composed of nitinol or a similar elastic metal and is formed by heat setting to a fully expanded shape. Typically, this heat setting can be performed in an oven or salt bath, and yields a ring that is larger in its formed diameter than the target ostium diameter. As a result, the ring 102 exerts an outward force against the ostial wall when deployed, holding the device 100 in contact with the tissue.
The force exerted by the expandable ring 102 can be adjusted to a desired level by varying the thickness or width of the ring 102. The diameter/expansion ratio of the expandable ring 102 can also be varied to yield a different profile of force applied to the tissue upon expansion of the ring. Generally, increased expansion pressure better secures the expandable ring 102 in place and may further create more prominent scarring at the target area.
In one preferred embodiment, the ring can be cut from a Nitinol tube having a diameter of about 0.150 inches and a wall thickness of about 0.015 inches. The struts of the ring can be cut about 0.015 inches wide and with a length between turnarounds of about 0.3 inches. For a target ostia having an internal diameter of 16 mm, this ring could be cut with six cells (i.e., it could have six turnarounds on both the top and the bottom). For this 16 mm target site, the ring could be formed to a diameter of about 20 mm. It should be noted that these dimensions are merely exemplary and that these dimensions can vary.
As discussed above, the clip loop 104 arcs over the diameter of the expandable ring 102 when the device is deployed. As a result, as shown in
With regard to delivery of the electrical block device 100 to the target site, the electrical block device 100 is first compressed into an undeployed state and is placed within a deployment sheath 108, as seen in
The guidewires 110 are conventional steerable guidewires having diameters typically in the range of 0.014 inches to 0.038 inches and must be steered down the two lumens past the bifurcation. Initially, the sheath 108 encapsulates the entire electrical block device 100 against the guiding catheter 112. However, as will be evident from the description below, this positioning configuration allows the electric block device 100 to easily slide off of the guiding catheter 112.
As the deployment sheath 108, guiding catheter 112, and electrical block device 100 are urged towards the pulmonary vein ostia, each guide wire 110 travels down a different pulmonary vein, centering the anchoring clip 106 on the bifurcation 116 of the pulmonary veins. The closer the guiding catheter 112 comes to the bifurcation 116, the more precisely aligned the anchoring clip 106 becomes with the bifurcation 116 until the anchoring clip 106 touches and finally “clips” onto the tissue of the bifurcation 116 via the barbs 105 located on the loops 103 of the clip 106.
The deployment process continues by simply sliding the deployment sheath 108 back past the expandable ring 102 as is best seen in
With the electrical block device 100 secured, the guiding catheter 112 and deployment sheath 108 are backed out of the atrium and removed from the body, leaving the device 100 in its target location as seen in
Due to the variation in geometry of pulmonary ostia, a pre-operation procedure such as MRI may be helpful to determine the geometry and approximate diameter of the target ostium. With this information, the electrical block device 100 may be better adjusted to suit the patient's target ostium by adjusting aspects such as the expanded diameter of the expandable ring 102, the length of the clip loop 104, or the size of anchoring clip 106.
Electrical Block Device with Anchoring Barbs
The previously described preferred embodiment positioned and secured the anchoring clip 106 before securing the expandable ring 102. However, the reverse order is also possible according to a preferred embodiment shown in
The preferred embodiment as shown
The barbs 220 are located around the perimeter of expandable ring 202, providing additional anchoring support when the expandable ring 202 is in the fully expanded position. The elastic clip loop 204 secures on either side of the expandable ring 202, in the same manner as the previous embodiments. However, a portion of each side of the elastic clip loop 204 has a multi-angled, wave-like elastic section 205. This elastic section 205 allows for a degree of variation in the distance between the position of the deployed expandable ring 202 and the bifurcation 216.
In operation, the electrical block device 200 with anchoring barbs 200 is loaded and deployed in a manner similar to the previously described embodiment. The expandable ring 202 is loaded within a deployment sheath 208 and around a guiding catheter, with the elastic clip loop 204 to sit between guide wires 210.
The electrical block device 200 is positioned near the desired target tissue of the ostia and the guide wires 210 are inserted into each pulmonary vein 214. When a desired target location has been achieved, the deployment sheath 208 is withdrawn so as to expose the expandable ring 202. The expandable ring 202 now being unconstrained, it expands and presses against the target tissue, pushing barbs 220 into the perimeter of the ostium 218.
Finally, the anchoring clip 206 is secured to the bifurcation 216 using guiding catheter 212 to apply pressure on the elastic clip loop 204 towards the bifurcation 216. This elastic section 205 enables the elastic clip loop 204 to stretch in response to the pressure and thus allows the anchoring clip 206 to secure to the bifurcation 216. At that point, the guiding catheter 212 and deployment sheath 208 may be removed from the patient.
In this manner, the electrical block device with anchoring barbs 200 provides the additional anchoring of barbs 220 while allowing for an alternative method of deployment. It should be understood that although this preferred embodiment allows the anchoring clip 206 to be clipped to the bifurcation 216 after expansion of the expandable ring 202, this order is not the only method of deployment. The electrical block device with anchoring barbs 200 may also be deployed in a similar fashion as electrical block device 100 of the first embodiment, as described above, where the anchoring clip 206 is clipped to the bifurcation 216 first, followed by deployment of the expandable ring 202.
Electrical Block Device without Sheath
More specifically, as in previous embodiments, the electrical block device 300 is loaded on a guiding catheter 312 for desired positioning near the perimeter of the ostium. A clip loop 304 is positioned between two guide wires 310 at the tip of guiding catheter 312.
The main distinction of this design lies in the expandable ring 302, which, unlike previous embodiments, has a series of holes 320 integrated into the expandable ring 302 structure. As seen in
The overall operation of this electrical block device 300 is similar to the previously mentioned embodiments above. The user positions the guiding catheter 312 near the bifurcation 316 of the pulmonary veins, then attaches the anchoring clip 306 using the guide wires 310 to assist in proper positioning. Next, the user manipulates the thin wire 322 to relieve the compression of expandable ring 302, allowing the ring 302 to expand to its full diameter, pressing against the target tissue.
To remove the wire 322 from the electrical block device 300, a user simply pulls one end of the wire 322 until the opposite end is free of both the electrical block device 300 and the guiding catheter 312. At this point, the electrical block device 300 and the guiding catheter 312 are no longer connected, so the user may remove the guiding catheter from the patient, allowing the electrical block device 300 to function as intended.
This technique of controlling the deployment of the blocking device with a tether wire is shown here for a bifurcated ostium. It is anticipated that this same technique can be applied for other ostial geometries as will be described below.
Alternative Electrical Block Device Designs
It should be understood that variations on the above described electrical block devices are possible and even desired, depending on a number of factors such as the geometric layout of the ostium of the pulmonary veins. Five variations may be seen in the preferred embodiments of
In this embodiment, the expandable ring 402 has a wave-like structure similar to previously described embodiments, yet its overall conformation curves upward at the outer sides of the pulmonary veins while the inner portion warps downward toward the left atrium. This overall bent configuration allows the electrical block device 400 to wedge into place at the ostium of the pulmonary veins.
The expandable vein anchor 406 has a circular wave-like (sinusoidal) structure which seats in a branch of the pulmonary vein just past the bifurcation and is connected to the expandable wire ring 408 with at least one wire. The vein anchor 406 has a similar structure to wave-like expandable rings described in previous embodiments. Functionally speaking, the vein anchor 406 expands in diameter against the pulmonary vein tissue providing additional anchoring force to secure the electrical block device 404 to the target position.
A variation of the embodiment in
Each of the dual vein anchors 414 seats within a branch of the pulmonary vein, just past the bifurcation, and self expands to a diameter larger than the target diameter of the pulmonary vein and thereby is secured against the pulmonary vein tissue. Wire supports 411 connect the dual vein anchors 414 to the expandable ring 412 and thereby secure the electrical block device 410 in place.
Turning now to
In this embodiment, the electrical block device 416 has an outer expandable ring 420 and an inner expandable ring 418. Both rings 420, 418 are secured together by wire support 422. The inner expandable ring 418 seats within a pulmonary vein, pressing outwardly against the vein tissue while the outer expandable ring 420 seats around the opening of the pulmonary vein. This embodiment allows the two rings to have either common or different functions. They can both be used to generate scarring as described above. They can also be configured such that the inner expandable ring 418 acts primarily as an anchoring/positioning ring and thereby allows outer expandable ring 420 to be held against the tissue around the ostium and to thereby serve as the scar generating ring.
Both rings 418, 420 have an angular wave-like design, allowing for compression in diameter during the pre-deployment phase and self-expansion during the deployment phase. In this fashion, electric block device 416 provides an alternative design for varying pulmonary geometries.
Electrical Block Device Coatings
The electrical block devices of the present invention as disclosed herein may be coated with a variety of chemicals or drugs to further enhance functionality. Such coatings may include drugs, chemicals, proteins, or other materials.
In one preferred embodiment of the present invention, portions of the electrical block device are coated with stenosis inhibiting drugs such as rapamycin or pacitaxel, as described in U.S. Pat. Nos. 6,273,913 and 6,231,600, the contents of which are hereby incorporated by reference.
The portions of the electrical block device which extend into the pulmonary vein may be of the most interest to coat, so as to limit the risk of pulmonary vein stenosis caused by the anchoring component of the implant yet not impacting the scarring response to the expandable ring desired in the ostium.
In another preferred embodiment, portions of the electrical block device are coated with a polymer material such as urethane or polyester, in order to promote the desired scarring around the ring while the anchoring components could remain uncoated or have a stenosis inhibiting coating as described above. Such a polymer coating could also be bio-absorbable, allowing for partial integration into the target tissue area.
In a further preferred embodiment, the expandable ring has a scar-inducing coating for enhancing the electrical blocking scar formation created by the expandable ring. Such coatings may include polymers, bioabsorbable polymers, platings (e.g., copper), polymers loaded with drugs (e.g., tetracycline), or drugs alone.
Expandable Ring Variations
Although the expandable electrical conduction block device of the present invention has been described in previous embodiments as primarily relying on a single zigzagging ring, it should be understood that a number of more complex variations are possible. Each variation may have different advantages beneficial to different pulmonary ostia geometries.
In a preferred embodiment seen in
The electrical conduction block device 500 has a primary ring 504 connected to a secondary ring 502 at the angled bend points or strut connection points of each ring. The primary ring 504 has a wider strut than the secondary ring 502, increasing the stiffness of the primary ring 504, while the secondary ring 502 is shorter in circumference than the primary ring 504. The differing circumferences of each ring allows for an expanded shape seen in
This two-ringed or two-cell design has a number of advantages, one of which is increased force per area on the target tissue by the secondary ring 502 relative to the primary ring 504. In this regard, the radial force exerted by the device against the wall of the target vessel is driven in large part by the width of the ring material. In other words, a wider ring can expand with more force than a thinner ring. A tissue necrosis mechanism for creating scars is a function of the pressure (force per unit area) exerted by the electrical block device against the target tissue. Since the primary ring 504 is wider than the secondary ring 502 and the two rings are connected together (allowing some of the radial expansion force generated by the primary ring 504 to be applied to the tissue contacted by the secondary ring 502), the secondary ring 502 thus causes a greater amount of force per area as between the two. As a result, the secondary ring 502 can be designed to create a desired scar line while the primary ring 504 can be designed to provide the primary anchoring function.
In this regard,
Another advantage to the dual ring design of the expandable ring 500 is that the secondary ring 502 is stretched into a nearly straight circle thereby allowing the secondary ring 502 to inscribe a substantially straight scar line around the internal circumference of the pulmonary vein. That is, the substantially straight scar line created by the secondary ring 502 avoids forming a scar line that extends axially upstream in the vein (away from the atrium) as would be the case if the secondary ring 502 was configured to have a wave-like shape in the deployed state.
This is important insofar as the electrical sources that must be isolated from the atrium in treating atrial arrhythmias are suspected to reside in close proximity to the ostium. These sources may be missed or inadequately isolated if the scar line, or a portion of the scar line, is created too far upstream in the vein (away from the atrium). Additionally, as discussed previously, the anatomy around the ostium often includes side branches or curves which make it more difficult to create a full circumferential scar line with a wave-like ring.
Finally, the electrical block device 500 that uses two rings (or “cells”) in this manner allows the formation of a discrete, narrow scar line yet has the positional stability of an axially extensive implant. In other words, the use of two rings 502, 504 in this manner leads to a narrow scar line around the ostium and also provides sufficient axial length so as to better ensure proper deployment and retention at the site. This is important as it is known that implants that have an increased ratio of diameter to axial length are more prone to misdeploy or “tumble” during deployment.
In a preferred embodiment of the expandable ring 500, the primary ring 504 and the secondary ring 502 are cut from a single tube of memory elastic metal, such as nitinol as shown in
Electro-polishing components of the expandable ring 500 may be necessary to prevent micro surface cracks from propagating when the device is strained in forming. These cracks can cause the device to fracture and must be eliminated by polishing before applying high strain to the components. Nitinol components of the expandable ring 500 can be electro-polished using percloric acid, nitric acid, or other compounds known to one skilled in the art. It may be desirable to form the device to a higher diameter in which case electro-polishing in stages may be necessary. This results from the fact that some expansion may be needed before being able to polish uniformly and from the fact that polishing may need to precede final expansion.
The primary ring 508 has a wave shape in its expanded form as shown in
Referring to 24 and
An advantage to this configuration is as follows. The larger surface area provided by the primary ring 536 leads to a greater dispersion of the expansion pressure (force per unit area) against the tissue by the primary ring 536 and thus mitigates (or even eliminates) the tendency of the struts of the primary ring 536 to penetrate or migrate through the wall of the vessel tissue. At a minimum, this greater surface will slow down the migration rate of the struts as compared to other embodiments and as to the struts of the secondary ring 538. It does not, however, negatively affect the desired expansion pressure (force per unit area) of the secondary ring 538. Hence, a first advantage is that the primary ring 536 may better facilitate the anchoring properties of the device 535 without degrading the scar inducing properties of the secondary ring 538.
Another advantage of this configuration relates to how the scar inducing properties of the device are executed by the device 535. If the struts 537 of the primary ring 536 are prevented from migrating into the wall of the tissue, this will better ensure the proper migration of the struts of the secondary ring 538. For example, if the struts of one side of the secondary ring 538 migrate fully through the wall on one side of the vessel before similar migration by the struts on the other side of the secondary ring 538, the circumferential tension (caused by the vessel tissue) necessary for urging the oppositely sided struts to continue their migration will be released unless an independent force is exerted against these oppositely sided struts. This independent force is provided by the struts 537 of the primary ring 536 as follows. Since the struts 537 of the primary ring 536 have not migrated into the tissue (by virtue of the larger surface area of these struts), they retain their expansion force. And because these struts 537 are independently connected to the struts of the secondary ring 538, then the oppositely sided struts of the secondary ring 538 will continue to encounter the outward expansion forces of the primary ring 536. As a result, uniform migration of the struts of the secondary ring 538 into the surrounding tissue is substantially assured even if the migration of the entire circumference of the secondary ring 538 does not occur simultaneously. In other words, by having the primary ring 536 serve essentially only as an anchoring ring (by virtue of its increased area), uniform outward expansion force is exerted against the struts of the secondary ring 538, regardless of when a portion of the secondary ring may migrate through the vessel tissue.
The barbs can be cut in the pattern shown in the flat sheet depiction of the device 530 in
Furthermore, the embodiment depicted in
It is desirable to deploy the device in a very controlled and accurate way for all embodiments of the electrical block devices discussed in accordance with the present invention. This includes the capability of deploying the device with a smooth release from the delivery device with no “jumping” of the position of the device in the target vessel. It also includes the capability of repositioning the device or to remove the device if the physician is not pleased with the deployed position of the device.
One embodiment of such a delivery system useful particularly for the electrical block devices described previously with respect to
This type of an assembly allows the device 500 to be deployed gradually by controlling the rate that the sheath 702 is pulled back along the catheter. This assembly also allows recovery or repositioning of the electrical block device 500 if the physician so wishes by advancing the sheath 702 back over the arms 539 and the electrical block device 500.
deployment of the electrical block device 500, this connection can be released by pulling this wire 708 back through these holes 714, 718 as shown in the right views of
As mentioned earlier, the concepts disclosed relative to the previously discussed connecting mechanisms could also be used to attach a delivery device to the electrical block device 500 at locations other than the strut of the secondary ring 502 as shown above. For example, a connecting mechanism such as is shown in
Variably Expandable Electrical Block Device
Yet another preferred embodiment of the present invention illustrates a variably expandable electrical block device 600 and deployment apparatus 616, illustrated in
A user may tighten or loosen these two control wires 618 to manipulate the size of the expandable ring 602.
The control wires 618 also serve the secondary function of deflecting the anchoring barbs 604 inward to prevent the sharp tips from being exposed until the control wire 618 is withdrawn. This deflection can be best seen in
One of the inherent benefits of this design lies in its ability to pass through significantly smaller diameter deployment sheaths for delivery to the desired target site, while expanding to an appropriate diameter, similar to the previously disclosed embodiments of this application.
Preferably, the expandable ring 602 could be cut from a flat sheet or tubing made from nitinol, having a thickness of about 0.015 inches and a height of about 0.070 inches. However, a variety of thicknesses and heights may be used so long as loading into a deployment sheath is possible and proper expansion of the expandable ring 602 may be achieved.
This embodiment of the present invention may be operated by first finding the pulmonary ostium target area with the loaded deployment apparatus 616 as depicted in
In this regard, the control arms 608 are devised so as to have sufficient axial strength so that the user may use them to push the expandable ring 602 forward. The user can track along a guide wire until either the expandable ring 602 wedges into the ostium or until the ring 602 is aligned with a predetermined axial marker of the desired deployment position.
When all of control wires 618 are pulled out, the anchoring barbs 604 are free to bend outwardly from the expandable ring 602 and penetrate the target tissue. Additionally, the deployment apparatus 616 is free to be retracted and removed from the patient, and the procedure may be finished, as best seen in
Optionally, additional anchoring devices may be used to help secure the electrical block device. Typically, such devices include staples or sutures which are not integral parts of the ring but which are delivered with a separate device that can be tracked into position and fasten the expandable ring to the tissue wall.
Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.
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|International Classification||A61F2/90, A61F2/02, A61F, A61F2/06|
|Cooperative Classification||A61F2002/9511, A61F2230/0054, A61F2/848, A61F2/91, A61F2220/0016, A61F2/2487, A61F2002/9665, A61F2/915, A61F2002/91558, A61F2002/91533, A61F2002/91525, A61F2002/8483, A61B17/320725|
|European Classification||A61F2/24W4, A61F2/915, A61F2/91|