U.S. patent application number 10/736863 was filed with the patent office on 2005-04-14 for lead stabilization devices and methods.
Invention is credited to Atkinson, Robert Emmett, Berman, Michael, Keith, Peter Trexler.
Application Number | 20050080472 10/736863 |
Document ID | / |
Family ID | 35542386 |
Filed Date | 2005-04-14 |
United States Patent
Application |
20050080472 |
Kind Code |
A1 |
Atkinson, Robert Emmett ; et
al. |
April 14, 2005 |
Lead stabilization devices and methods
Abstract
Devices and methods for stabilizing a lead in a cardiac
vein.
Inventors: |
Atkinson, Robert Emmett;
(White Bear Lake, MN) ; Keith, Peter Trexler; (St.
Paul, MN) ; Berman, Michael; (Minnetonka,
MN) |
Correspondence
Address: |
ROBERT E. ATKINSON, PC
2679 RIVIERA DRIVE SOUTH
WHITE BEAR LAKE
MN
55110
US
|
Family ID: |
35542386 |
Appl. No.: |
10/736863 |
Filed: |
December 16, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60510663 |
Oct 10, 2003 |
|
|
|
Current U.S.
Class: |
607/126 |
Current CPC
Class: |
A61F 2/86 20130101; A61F
2230/005 20130101; A61F 2/95 20130101; A61F 2230/0076 20130101;
A61N 1/057 20130101; A61F 2220/0008 20130101 |
Class at
Publication: |
607/126 |
International
Class: |
A61N 001/05 |
Claims
1-28. (canceled)
29. A system for stabilizing an electrical lead in a coronary
vessel, comprising: an electrical lead having a proximal portion
and a distal portion with a lumen extending therethrough; and an
intravascular anchoring device including an anchor and an elongate
tether, the tether detachably connected to the anchor and extending
proximally from the anchor, the tether extending through the lumen
of the lead with the anchor disposed distally of the lead, wherein
the lead is longitudinally movable with respect to the anchoring
device.
30. A system as in claim 29, further comprising a connector for
limiting longitudinal movement between the lead and the anchoring
device, wherein the connector is insertable into the lumen of the
lead adjacent the tether.
31. A system as in claim 29, wherein the tether in nonelectrically
conductive.
32. A system as in claim 29, wherein the tether comprises a
braid.
33. A system as in claim 29, wherein the tether comprises a
polymeric braid.
34. A system as in claim 29, wherein the anchor comprises a
self-expanding structure.
35. A system for stabilizing an electrical lead in a coronary
vessel, comprising: an electrical lead having a proximal portion
and a distal portion with a lumen extending therethrough; and an
intravascular anchoring device including a self-expanding anchor
and an elongate tether, the tether connected to the anchor and
extending proximally from the anchor, the tether extending through
the lumen of the lead with the anchor disposed distally of the
lead, wherein the lead is longitudinally movable with respect to
the anchoring device.
36. A system as in claim 35, further comprising a connector for
limiting longitudinal movement between the lead and the anchoring
device, wherein the connector is insertable into the lumen of the
lead adjacent the tether.
37. A system as in claim 35, wherein the tether in non-electrically
conductive.
38. A system as in claim 35, wherein the tether comprises a
braid.
39. A system as in claim 35, wherein the tether comprises a
polymeric braid.
40. A system as in claim 35, wherein the tether is detachable from
the anchor.
41. A system for stabilizing an electrical lead in a coronary
vessel, comprising: an electrical lead having a proximal portion
and a distal portion with a lumen extending therethrough; and an
intravascular anchoring device including an anchor and an elongate
non-electrically conductive tether, the tether connected to the
anchor and extending proximally from the anchor, the tether
extending through the lumen of the lead with the anchor disposed
distally of the lead, wherein the connector is insertable into the
lumen of the lead adjacent the tether.
42. A system as in claim 41, further comprising a connector for
limiting longitudinal movement between the lead and the anchoring
device, wherein the connector is insertable into the lumen of the
lead adjacent the tether.
43. A system as in claim 41, wherein the anchor comprises a
self-expanding structure.
44. A system as in claim 41, wherein the tether comprises a
braid.
45. A system as in claim 41, wherein the tether comprises a
polymeric braid.
46. A system as in claim 41, wherein the tether is detachable from
the anchor.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 60/510,663, filed Oct. 10, 2003, entitled
LEAD STABILIZATION DEVICES AND METHODS to Atkinson et al., the
entire disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention generally relates to medical devices
and methods. More specifically, the present invention relates to
medical devices and methods for stabilizing leads in cardiac
vasculature.
BACKGROUND OF THE INVENTION
[0003] Heart failure is an increasingly common condition worldwide.
Cardiac resynchronization therapy (CRT) has shown great promise as
a treatment for a large percentage of patients in various stages of
heart failure. CRT involves cardiac pacing of both the left and
right ventricles of the heart (biventricular pacing), which causes
both ventricles to beat simultaneously, greatly improving the
pumping efficiency of the heart. Typically, the lead that
stimulates the left ventricle is positioned via the coronary sinus
into a cardiac vein along the free wall of the left ventricle.
[0004] There are numerous challenges in successfully positioning
the left ventricular lead, including accessing the coronary sinus
and veins, advancing the leads to a position which yields proper
stimulation, and preventing subsequent lead dislodgement during
removal of delivery devices. Post procedural challenges related to
the left ventricular lead include lead dislodgement prior to
fibrosis, loss of stimulation capture, and lead removal
necessitated by infection.
[0005] Currently available left ventricular leads have generally
been designed to facilitate effective delivery and provide fatigue
resistance, and are particularly susceptible to dislodgement both
intra-procedurally and post-procedurally. Efforts to incorporate
more aggressive anchoring into the lead body have generally been
insufficient for preventing dislodgment, and/or have compromised
effective delivery, fatigue resistance and subsequent lead
removal.
SUMMARY OF THE INVENTION
[0006] Therefore, a need exists to enable effective lead
stabilization without compromising lead delivery, resistance to
lead fatigue, or lead removal. To address this need, various
exemplary non-limiting embodiments are described herein which
provide devices and methods for acute and/or chronic lead
stabilization. By way of example, not limitation, the lead
stabilization mechanisms described herein may be separate from but
cooperative with the lead, thus allowing independent delivery and
function. To this end, the lead may be designed for effective
delivery and fatigue resistance, and the stabilization mechanism
may be designed for effective acute and/or chronic anchoring to
prevent lead dislodgement. In addition, the stabilization
mechanisms described herein may be separable from the lead to
permit subsequent lead removal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is an anterior view of a human heart and associated
vasculature;
[0008] FIG. 2 is a posterior view of a human heart and associated
cardiac venous vasculature;
[0009] FIG. 3 is a schematic side view of a lead and an anchor
device in the form of a stent disposed in a cardiac vein;
[0010] FIG. 4 is a schematic side view of a lead and an alternative
anchor device in the form of a stent disposed in a cardiac
vein;
[0011] FIG. 5 is a schematic side view of a lead disposed in a
coronary vein and an alternative anchor device in the form of a
stent disposed in a secondary cardiac vein;
[0012] FIG. 6 is a schematic side view of an anchor delivery device
for use in delivering the anchor devices illustrated in FIGS.
3-5;
[0013] FIG. 7 is a schematic side view of a lead and an alternative
anchor device in the form of a coil disposed in a cardiac vein;
[0014] FIG. 8 is a schematic side view of a lead and an alternative
anchor device in the form of a bundle disposed in a cardiac
vein;
[0015] FIG. 9 is a schematic side view of a lead disposed in a
cardiac vein and an alternative anchor device in the form of a plug
disposed in a secondary cardiac vein;
[0016] FIGS. 10 and 11 are schematic side views of a lead and
alternative anchor devices in the form of wedges disposed in a
cardiac vein;
[0017] FIG. 12 is a schematic illustration of a release mechanism
in the form of a connector cutter;
[0018] FIG. 13 is a schematic side view of a lead disposed in a
cardiac vein and an anchor device in the form of a coiled stent
disposed near the ostium of the coronary sinus;
[0019] FIG. 13A is a cross sectional view taken along line A-A in
FIG. 13;
[0020] FIG. 13B is side sectional view of the fastener illustrated
in FIG. 13;
[0021] FIG. 14 is a schematic side view of a lead disposed in a
cardiac vein and an anchor device in the form an anchor catheter;
and
[0022] FIG. 15 is a detailed schematic view of the anchor catheter
illustrated in FIG. 14.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The following detailed description should be read with
reference to the drawings in which similar elements in different
drawings are numbered the same. The drawings, which are not
necessarily to scale, depict illustrative embodiments and are not
intended to limit the scope of the invention.
[0024] With reference to FIGS. 1 and 2, the anatomy of a human
heart (H) is illustrated. FIG. 1 shows the heart from the anterior
side, with the right chambers of the heart shown in section. FIG. 2
shows the heart from the posterior side, and illustrates the
cardiac veins, including the coronary sinus (CS) and its associated
venous branches (great cardiac vein, left marginal vein, left
posterior ventricular vein, middle cardiac vein, and small cardiac
vein). The CS carries the primary venous return for the cardiac
circulation, with the venous branches distributed about the heart
and draining into the CS. The CS circumnavigates the left side of
the heart, generally between the left atrium (LA) and the left
ventricle (LV). The CS drains into the right atrium (RA) at the
ostium.
[0025] Left ventricular leads are typically implanted with the
proximal end connected to a pulse generator in a subcutaneous or
submuscular pocket, and the distal end (electrode(s)) disposed in
one of the cardiac veins to stimulate the left ventricle. The lead
body typically extends from the pulse generator in the subcutaneous
or submuscular pocket, through the vein wall and into the left
subclavian vein (LSV), through the left brachio-cephalic vein
(LBV), down the superior vena cava (SVC) and into the right atrium
(RA), into the CS and into the target cardiac vein. The venous
circulation is usually accessed by introducing delivery catheters
(called guide catheters or guide sheaths) from a venous arteriotomy
in the LSV to the CS ostium, following the dashed line shown in
FIG. 1. Once the CS is cannulated by a delivery catheter, a
coronary venogram is obtained to visualize the cardiac veins. The
lead is advanced into the CS and the desired cardiac vein,
following an exemplary path indicated by the dashed line shown in
FIG. 2.
[0026] There are generally two categories of LV leads,
over-the-wire (OTW) leads and stylet-delivered leads. OTW leads
incorporate a guide wire lumen which extends through the entire
lead body, emerging at the tip of the lead. Navigation within the
CS and cardiac veins is performed by advancing a steerable guide
wire to a desired location in a cardiac vein, and the lead is then
advanced over the guide wire. Stylet delivered leads have a stylet
lumen which extends through the lead body, but typically terminates
proximal of the distal tip. A shaped styled is positioned in the
stylet lumen and the lead and stylet are advanced together to
navigate the lead to a desired location in a cardiac vein.
[0027] Once the lead is positioned in a location that yields
acceptable stimulation (capture), the delivery catheter is removed.
Depending on the particular lead, and the type of electrical
connector utilized, removal is accomplished either by withdrawing
the delivery catheter over the proximal end of the lead, or by
splitting the delivery catheter as it is removed over the proximal
end of the lead. In some situations, removal of the delivery
catheter may dislodge the lead, as the stability of the lead
position is often quite tenuous. Even if the lead is not dislodged
during removal of the delivery catheter, the beating of the heart
and other patient activities can cause lead movement or
dislodgement, leading to potential loss of capture (effective
pacing of the LV).
[0028] With reference to FIG. 3, a pacing lead 10 and an anchor
device in the form of a stent 20 are schematically shown disposed
in a cardiac vein CV. Generally, the CV generically refers to
venous braches of the coronary sinus such as the great cardiac
vein, left posterior ventricular vein, middle cardiac vein, small
cardiac vein, or other cardiac vein that leads to the left
ventricle, and preferably that leads to the apex of the left
ventricular free wall or that otherwise provides for effective
pacing of the left ventricle. Those skilled in the art will
recognize that because of anatomic variation, the precise name and
position of the CV will vary.
[0029] Lead 10 may comprises a conventional pacing lead having an
elongate body or shaft 12 and one or more electrodes 14 connected
to a pulse generator (not shown) by corresponding wires or traces
inside the lead body 12. Lead 10 is generally designed to be very
flexible and fatigue resistant to permit free cardiac movement, to
minimize tissue trauma, and to withstand repeated flexure primarily
caused by the beating heart. The electrodes 14 are typically
positioned on or near the wall of the vein facing the heart to
establish effective conduction into the heart wall.
[0030] Stent 20 may be self-expandable or balloon expandable, for
example, and may be formed of a biocompatible metal material such
as stainless steel, Nitinol, Elgiloy, or MP35N. Alternatively,
stent 20 may be formed of a biodegradable polymeric material such
as poly-L-lactic acid, polyglycolic acid, or polycaprolactone, or
other biodegradable materials such as those used for biodegradable
sutures. In the case of polymeric materials used for stent 20, the
polymer may be loaded with a radiopaque agent such as barium,
bismuth subcarbonate, etc. to facilitate x-ray visualization.
Generally speaking, all of the anchors of the anchor devices
described herein may be formed of the aforementioned materials and
may be radiopaque.
[0031] Stent 20 may be connected to lead 10 by an elongate
connector 30. Elongate connector 30 may comprise a tether that is
flexible and fatigue resistant such as a braided cord of a high
strength biocompatible polymer such as polyester, polypropylene, or
polyethylene (e.g., Spectra brand), and may be partially or fully
covered or coated with a material that promotes tissue in-growth
such as ePTFE. The tissue in-growth promoting material may serve to
secure the elongate member 30 to the lead 10 and/or prevent
bacteria migration along the elongate member 30.
[0032] In the embodiment illustrated in FIG. 3, the elongate member
or tether 30 extends through the lumen (e.g., guide wire lumen) of
the lead 10. This embodiment is particularly suitable for OTW leads
that typically have a guide wire lumen extending therethrough. The
proximal end of the tether 30 may extend out the proximal end of
the lumen of the lead 10, and may be connected to the lead 10 by
tying a knot that is larger than the diameter of the lumen, for
example. Alternatively, the proximal end of the tether 30 may be
connected to the proximal end of the lead 10 by trapping the tether
30 in the lumen of the lead 10 with a wedge or pinching it between
the electrical connector of the lead 10 and the socket of the pulse
generator. The distal end of the tether 30 may be connected to the
stent 20 by tying the tether 30 in a knot around a strut of the
stent 20, or swaging and end of the tether 30 between struts of the
stent 20, for example.
[0033] In this embodiment, the stent 20 and tether 30 may be
deployed before the lead 10 is delivered. The stent 20 may be
deployed in a distal portion of the target CV with a delivery
device as described in more detail with reference to FIG. 6. Once
deployed, the proximal end of the tether 30 may be inserted into
the distal end of the lumen extending through the lead 10, and the
lead 10 may then be advanced over the tether 30 and into the CV to
the desired position, and pacing tests may be performed to
ascertain LV pacing capture. Once the lead 10 is in the desired
position, the proximal end of the tether 30 may be secured to the
proximal end of the lead 10 as described previously.
[0034] If it is necessary or desired to remove or reposition the
lead 10, the lead 10 may be removed from the CV by disconnecting
the tether 30 from the lead 10 (e.g., by cutting the knot in the
tether 30 at the proximal end of the lead 10), the tether 30 may be
removed from the CV by disconnecting the tether 30 from the stent
20 (e.g., by using a cutting device as described in more detail
with reference to FIG. 12), and the stent 20 may be left in place
in the CV without compromising blood flow through the CV.
[0035] With reference to FIG. 4, an alternative anchor device
arrangement is shown schematically. In this embodiment, rather than
extending through the lumen of the lead 10, the tether 30 extends
along side the lead 10. This embodiment is particularly suitable
for stylet-delivered leads that typically do not have a lumen
extending therethrough, but may be used with either
stylet-delivered or OTW leads. This embodiment also allows for the
delivery of the anchor device either before or after lead 10
placement.
[0036] The tether 30 may be connected to the lead 10 by a fastener
such as collar 40. Collar 40 may comprise a short dual lumen tube
including a relatively large lumen to accommodate the lead 10
therethrough and a relatively small lumen to accommodate the tether
30 therethrough. Collar 40 may be fixedly connected to the lead 10
if the anchor device is delivered prior to the lead 10 by swaging,
adhesive, etc. To facilitate delivery of the lead after placement
of the lead 10, the collar 40 may be slidable over the lead 10 and
lock in place adjacent the distal potion of the lead 10 using a
mating geometry such as a detent on the outer surface of the lead
10 that receives a protrusion extending from the inside surface of
the collar 40. Alternatively, the outer surface of the lead 10 may
include a protrusion such as a stepped ridge 45 that abuts the
distal end of the collar 40 as the collar 40 is advanced over the
lead 10 in order to prevent proximal movement of the lead 10
relative to the collar 40. With this alternative, the stepped ridge
45 may be an integral extension of the outer surface of the lead 10
or a separate component fixedly connected to the lead 10.
[0037] The tether 30 may be effectively connected to the collar 40
to prevent proximal movement of the collar 40 relative to the
tether 30 by utilizing a knot or stop 35 that is slid down the
length of the tether 30. A knot may be made in the tether at its
proximal end and advanced distally to the collar 40 using a
conventional knot pusher. A stop 35 may be used and configured to
readily advance distally over the tether 30 and resist retraction
proximally. For example, stop 35 may comprise a short tubular
segment having proximal facing flanges extending from the inside
surface that selectively engage the tether 30 only when the stop 35
is advanced in the proximal direction relative to the tether 30. To
facilitate removal of the lead 10, the stop 35 may be cut or the
tether 30 may be cut between the stop 35 and the collar 40 using
the cutting device described with reference to FIG. 12.
[0038] To facilitate advancement of the collar 40 over the lead 10
and to facilitate advancement of the stop 35 over the tether 35, a
dual lumen advancement sheath 50 may be slid (pushed) over the lead
10 and tether 30. Sheath 50 may comprise an elongate dual lumen
tube having a length sufficient to extend over the lead 10, through
the venous vasculature, and out the venous access site, with one
lumen to accommodate the lead 10 and another lumen to accommodate
the tether 30. Sheath 50 may include a slit (not shown) along the
length thereof to facilitate peeling over the lead 10. Sheath 50
may be removed over the lead 10 and tether 30 after advancement of
the collar 40 and stop 35, or it may be left implanted to contain
the tether 30 relative to the lead 10.
[0039] With reference to FIG. 5, an alternative anchor device
arrangement is shown schematically. In this embodiment, the stent
20 is deployed in a secondary cardiac vein (SCV) and connected via
tether 30 and collar 40 to lead 10 as described with reference to
FIG. 4. Positioning the stent 20 in a SCV enhances the anchoring
effect and, because of collateral venous circulation, reduces the
possibility of adverse effects if the stent 20 were to become
occluded.
[0040] With reference to FIG. 6, a schematic side view of an anchor
delivery catheter device 100 for use in delivering anchor devices
such as stent 20 as described in connection with the embodiments of
FIGS. 3-5. In this embodiment, the delivery device 100 is
configured to deliver an elastically expandable (self-expanding)
stent, but a balloon catheter type delivery device may
alternatively be utilized to deliver a plastically deformable
(balloon expandable) stent. In the illustrated embodiment, the
delivery catheter 100 may include an inner tube 110 coaxially
disposed in an outer tube 120. The stent 20 may be pre-loaded
inside the outer tube 120, near its distal end. The distal end of
the inner tube 110 abuts the proximal end of the stent 20, and may
be advanced distally with respect to the outer tube 120 as
indicated by arrow 115 to advance stent 20 out of the distal end of
the outer tube 120. The tether 30 may be disposed between the inner
tube 110 and the outer tube 120.
[0041] To facilitate delivery, a guide wire 130 may be used to
initially navigate the CV. Once the guide wire 130 is in the
desired position, the delivery catheter 100 with the pre-loaded
stent 20 therein may then be advanced over the proximal end of the
guide wire 130 and advanced thereover to the desired deployment
position. The inner tube 110 may be advanced in the distal
direction with respect to the outer tube 120 as indicated by arrow
115 to deploy the stent 20 in the CV. Once the stent 20 is
deployed, the delivery catheter 100 may be removed.
[0042] With reference to FIG. 7, an alternative anchor device
arrangement is shown schematically. In this embodiment, a coil 70
is deployed distal of the lead 10 and connected via tether 30 to
lead 10 as described with reference to FIG. 3. The proximal end of
the coil 70 may be connected to the distal end of the tether 30 at
connection 75, and the coil 70 may comprise a resilient structure
such as a metal wire formed of any of the materials described with
reference to stent 20. Coil 70 may be delivered via a lumen (e.g.
guide wire lumen) extending through the lead 10 and is particularly
suitable for an OTW lead. The coil 70 may be advanced through the
lumen of the lead 10 using a push tube (not shown) having
sufficient column strength disposed over the tether 30 that abuts
the connection 75 between the coil 70 and the tether 30.
[0043] To accommodate delivery through the lumen extending through
the lead 10, the coil 70 may have a delivery configuration wherein
the coil 70 is elongated to have a reduced profile sufficiently
small to fit into the lumen, and a deployed configuration wherein
the coil 70 is radially expanded to have an expanded profile
sufficiently large to frictionally engage the wall of the CV. The
coil 70 may be highly elastic such that it assumes the deployed
configuration automatically upon advancement out of the distal end
of the lead 10, or the coil may be actuated (e.g., thermally) upon
advancement out of the distal end of the lead 10 to assume the
deployed configuration.
[0044] With reference to FIG. 8, an alternative anchor device
arrangement is shown schematically. In this embodiment, a bundle 80
is deployed distal of the lead 10 and connected via tether 30 to
lead 10 as described with reference to FIG. 3. The proximal end of
the bundle 80 may be connected to the distal end of the tether 30
at connection 85, and the bundle 80 may comprise a resilient
structure such as a metal wire formed of any of the materials
described with reference to stent 20. Bundle 80 may be delivered in
the same manner as and may have the same or similar characteristics
as coil 70 described with reference to FIG. 7. Bundle 80, as
opposed to coil 70, may have an occlusive effect, and therefore may
be particularly suitable for a SCV to take advantage of collateral
venous circulation.
[0045] With reference to FIG. 9, an alternative anchor device
arrangement is shown schematically. This embodiment is similar to
the embodiment illustrated in FIG. 5, except that a plug 90 is used
in place of stent 20. The plug 90 may comprise a curable adhesive
(e.g., cyanoacrylate, EVA in a DSMO solvent) or an embolic coil,
for example, such as those conventionally used in occluding blood
vessels and aneurisms. Plug 90 may be deployed in a SCV using a
conventional embolic delivery system and connected via tether 30
and collar 40 to lead 10 as described with reference to FIG. 4.
Positioning the plug 90 in a SCV enhances the anchoring effect, and
despite the occlusive effect of the plug 90, the possibility of
adverse effects are reduced if not eliminated due to collateral
venous circulation.
[0046] With reference to FIGS. 10 and 11, alternative anchor device
arrangements are shown schematically. In these embodiments, a wedge
140 or 150 is deployed adjacent the distal portion of the lead 10,
such as proximal of electrodes 14. Wedges 140 and 150 frictionally
engage the lead body 12 and the wall of the CV, to lodge the lead
10 in the desired position in the CV. The wedges 140 and 150 may be
connected to tether 30 to facilitate subsequent removal. Wedges 140
and 150 may comprise any of the materials discussed with reference
to stent 20. Wedges 140 and 150 are particularly suitable for
deployment after the lead 10 has been delivered to the desired
position.
[0047] With specific reference to FIG. 10, wedge 140 includes a
body portion 142 and optional threads 144. Body portion 142 may
include a perfusion lumen extending therethrough to permit blood
perfusion from the distal end to the proximal end of the wedge 140.
The wedge body 142 (or the wedge threads 144 if used) may have a
diameter slightly greater than the diameter of the lumen of the CV
less the diameter of the lead 10 in order to provide a snug
frictional fit therebetween. Wedge 140 may be delivered into the
desired position utilizing a push tube 60 advanced over a guide
wire (not shown), for example, wherein the push tube 60 has
sufficient column strength to push the wedge 140 alongside the lead
10 with the distal end 65 of the push tube abutting the proximal
end of the wedge 140 and the tether 30 extending through the push
tube. The push tube may also have sufficient torsional strength
with a distal end 65 that mates with the proximal inside diameter
of the wedge 140 such that the wedge 140 may be rotated to engage
or disengage the threads 144 with the lead 10 and the wall of the
CV.
[0048] With specific reference to FIG. 11, wedge 150 comprises a
short dual lumen having one lumen to accommodate the lead 10 and
another (crescent shaped) lumen to permit blood perfusion from the
distal end to the proximal end of the wedge 150. The wedge 150 may
be tapered and may have a diameter slightly greater than the
diameter of the lumen of the CV less the diameter of the lead 10 in
order to provide a snug frictional fit therebetween. Stepped ridge
45 prevents proximal movement of the lead 10 relative to wedge 150
as described previously. Wedge 150 may be delivered into the
desired position utilizing a push tube 50 advanced over the lead
10, as described previously.
[0049] With reference to FIG. 12, a cutting device 160 is shown
schematically. Cutting device 160 may be used to cut tether 30
and/or stop 35 in order to disconnect the tether 30 from the anchor
device, such as stent 20. Cutting device 160 is merely an example
of a variety of cutting mechanisms that may be used to sever the
connection of the tether 30 from the anchor device. For example,
the tether 30 may be equipped with two internal wires connected to
a distal electrolytic fuse that separates (melts) upon the
application of electrical current, such as those used for
detachable embolic coils.
[0050] In this exemplary embodiment, cutting device 160 includes an
outer tube 162 and an inner tube 164 coaxially disposed and movable
therein. The outer and inner tubes 162 and 164 may have a length
sufficient to extend from outside the vascular access site to the
anchor device, and may be configured for intravascular navigation
and advancement over tether 30. The distal end of the inner tube
164 may have a sharpened edge and may be formed of a material that
retains a cutting edge (e.g., metal). A cutting hole 168 is
provided adjacent the distal end of the outer tube 162 through
which the tether 30 may be threaded. The distal circumference of
the cutting hole 168 may be sharpened and may be formed of a
material that retains a cutting edge (e.g., metal) After the
cutting device is advanced over the tether 30 to the desired
cutting site, the inner tube 164 may be advanced distally as
indicated by arrow 166, with the sharpened distal end of the inner
tube 164 and the sharpened cutting hole 168 acting as shears to cut
the tether 30 at the cutting hole 168.
[0051] With reference to FIG. 13, a lead 10 is shown disposed in a
CV, with an anchor device in the form of a coiled stent 200
disposed near the ostium of the CS. The coiled stent 200 may be
positioned near the ostium of the CS, where the vessel diameter is
large enough to resist becoming occluded by the presence of the
coiled stent 200 next to the lead 10. However, it is contemplated
that the coiled stent 200 may be placed elsewhere within the CS or
CV in which the lead is positioned. As seen in FIG. 13A, the lead
10 is eccentrically disposed in the lumen of the CS to define a
relatively large crescent shaped blood perfusion lumen.
[0052] Coil stent 200 may be formed of a resilient material such as
Nitinol, Elgiloy, MP35N, or stainless steel. Coiled stent 200 could
also be formed of degradable materials such as those described in
reference to stent 20 above. Coiled stent 200 may be releasably
attached to the lead 10 utilizing collar 210, and collar 210 may
frictionally engage the body 12 of lead 10, thus facilitating
anchoring of the lead within the coronary sinus or cardiac
vein.
[0053] With reference to FIG. 13B, the collar 210 may comprise a
relatively short tube 212, and may include one or more proximally
oriented grips 218. Grips 218 may be in the shape of finger-like
projections, or circular ribs either partially or completely
extending circumferentially around the inside of tube 212. Grips
218 facilitate the advancement of the collar 210 in a distal
direction for delivery over lead 10, but resist proximal movement
once the collar 210 is positioned in a desired anchoring location.
Grips 218 may be formed of a soft resilient material such as
silicone, polyurethane, polyether-block-amide, or the like.
[0054] To facilitate subsequent removal of the lead 10, the coiled
stent 200 may be connected to the collar 210 in a detachable
manner. For example, the coiled stent 200 may be connected to the
collar 210 utilizing a biodegradable adhesive connecting adjacent
portions of the coil 200 to the collar 210. Such an adhesive may
degrade after the lead 10 has chronically anchored to the wall of
the CS by normal tissue encapsulation. After the adhesive has
degraded, the lead 10 (along with collar 210) may be removed
utilizing standard techniques, with the coiled stent 200 remaining
in the CS.
[0055] Alternatively, the coiled stent 200 may be secured to the
collar 210 utilizing a retractable pin 220. In this alternative
embodiment, collar 210 may include two angled flanges 214
collectively defining a recess 216 in which stent coil 200 may
reside. Pin 220 may span the length of the recess 216 between the
flanges 214, extending over the coiled stent 200 to retain the coil
stent 200 in the recess 216, thus providing a connection between
the stent coil 200 and the collar 214. Subsequent release of the
stent coil 200 from the lead 10 may be accomplished by removing pin
220 using tether 30 which extends from the proximal end of the lead
10 to the pin 220. The proximal end of the pin 220 is connected to
the distal end of the tether 30, and the pin 220 may be removed by
pulling the tether 30 proximally. After the pin 220 is removed, the
lead 10 and collar 210 are free from the stent coil 200 and may be
removed with standard techniques, leaving stent coil 200 in the
CS.
[0056] Delivery and deployment of the stent coil 200 and collar 210
may be facilitated by deployment sheath 230. The deployment sheath
230 may comprise a tubular catheter, having a lumen extending
therethrough to accommodate the lead 10 and the stent coil 200.
Alternatively, the lumen in the deployment sheath 230 may extend
from a distal opening to a mid-shaft opening as used in
conventional monorail style balloon catheters. After lead 10 has
been positioned by standard techniques to a desired position, the
stent coil 200 and collar 210 may be loaded on the proximal end of
the lead 10. Coil 200 may be initially in a compressed condition,
and loaded in the inside of the deployment sheath 230. If the lead
10 has a large diameter proximal connector, an optional slit 215
may be provided in the collar 220 to facilitate loading over the
large diameter connector. In this case, the collar 210 and coil 200
may be positioned on the lead body 12 before the coil 200 is loaded
into the deployment sheath 230. The deployment sheath 230 may be
advanced distally down the body 12 of the lead 10 until the stent
coil 200 and collar 210 are in the desirable location. The
deployment sheath 230 may then be withdrawn proximally, with the
collar 210 and stent coil 200 remaining in position on the lead 10
due to grips 218 on collar 210. As the stent coil 200 emerges from
the deployment sheath 230, it expands to engage the wall of the CS.
The deployment sheath 230 can then be removed from the lead 10.
[0057] FIGS. 14 and 15 illustrate an anchor device in the form of
an anchoring catheter 300, which may be utilized to secure the
position of lead 10, particularly during the removal of the guide
sheath (guide catheter) used in the delivery of the lead 10. As
described above, the lead stability is particularly vulnerable
during the removal of the guide sheath.
[0058] In use, the anchoring catheter 300 is positioned next to the
lead 10 after lead 10 has been positioned in a desired location.
Anchoring catheter 300 may be advanced within the guide sheath (not
shown), generally parallel to the lead body 12, or may be advanced
outside the guide sheath. An expandable member such as a balloon
314 is inflated to frictionally secure lead 10 against the wall of
the blood vessel. The guide sheath can then be removed without
inadvertent dislodgement of the lead 10. The anchoring catheter 300
can then be removed. Since anchoring catheter 300 is next to and
not surrounding the lead body 12, removal of the anchoring catheter
300 does not pose a risk of dislodging lead 10.
[0059] With particular reference to FIG. 15, anchoring catheter 300
is shown in more detail. Shaft 312 may comprise a proximal shaft
portion 312A connected by adhesive, for example, to a distal shaft
portion 312B. A luer adaptor 316 may be connected to the proximal
end of the proximal shaft portion 312A for connection to an
inflation apparatus (not shown) such as a syringe. An inflatable
balloon 314 may be connected to the distal end of the distal shaft
portion 312B, and may be formed of elastomeric material or a molded
inelastic material.
[0060] Proximal shaft portion 312A may be relatively stiff and may
be formed of a metallic tube such as a stainless steel hypotube.
Distal shaft portion 312B may be relatively flexible and may be
formed of a polymeric tube, for example. To facilitate advancement
of the flexible distal shaft portion 312B and the balloon 314, a
core wire may be connected to and extend from the distal end of the
proximal shaft portion 312A. The core wire 320 may comprise a metal
wire such as a tapered stainless steel mandrel.
[0061] Core wire 320 extends to the distal end of the balloon 314,
and may extend beyond with an atraumatic spring tip, for example.
The distal end of the balloon 314 may be bonded to the core wire
320, and the proximal end of the balloon 314 may be bonded to the
distal end of the distal shaft portion 312B. Within the shaft 312
is a lumen through which inflation medium is infused to inflate
balloon 314.
[0062] Those skilled in the art will recognize that the present
invention may be manifested in a variety of forms other than the
specific embodiments described and contemplated herein.
Accordingly, departures in form and detail may be made without
departing from the scope and spirit of the present invention as
described in the appended claims.
* * * * *