U.S. patent application number 11/684982 was filed with the patent office on 2007-08-23 for methods for restoring blood flow within blocked vasculature.
Invention is credited to Martin S. Dieck, Brian B. Martin.
Application Number | 20070198030 11/684982 |
Document ID | / |
Family ID | 38335001 |
Filed Date | 2007-08-23 |
United States Patent
Application |
20070198030 |
Kind Code |
A1 |
Martin; Brian B. ; et
al. |
August 23, 2007 |
METHODS FOR RESTORING BLOOD FLOW WITHIN BLOCKED VASCULATURE
Abstract
The devices and methods described herein relate to clearing of
blockages within body lumens, such as the vasculature, by
addressing the frictional resistance on the obstruction prior to
attempting to translate and/or mobilize the obstruction within the
body lumen.
Inventors: |
Martin; Brian B.; (Boulder
Creek, CA) ; Dieck; Martin S.; (Menlo Park,
CA) |
Correspondence
Address: |
LEVINE BAGADE HAN LLP
2483 EAST BAYSHORE ROAD, SUITE 100
PALO ALTO
CA
94303
US
|
Family ID: |
38335001 |
Appl. No.: |
11/684982 |
Filed: |
March 12, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11671450 |
Feb 5, 2007 |
|
|
|
11684982 |
Mar 12, 2007 |
|
|
|
60765496 |
Feb 3, 2006 |
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Current U.S.
Class: |
606/127 |
Current CPC
Class: |
A61B 17/22012 20130101;
A61B 17/320725 20130101; A61B 2017/00867 20130101; A61B 2017/22094
20130101; A61B 2017/2212 20130101; A61B 2017/00862 20130101; A61B
2017/22051 20130101; A61B 2017/22034 20130101; A61B 2017/2215
20130101; A61B 17/221 20130101 |
Class at
Publication: |
606/127 |
International
Class: |
A61B 17/22 20060101
A61B017/22 |
Claims
1.-108. (canceled)
109. A method for removing an obstruction from a blood vessel, the
method comprising: converting an obstruction removal device into a
high friction mode, from a low friction mode over the obstruction,
where the high friction mode increases frictional contact between
the obstruction removal device and the obstruction; and withdrawing
the traversing device and obstruction from the blood vessel.
110. The method of claim 109, further comprising positioning the
obstruction removal device comprising at least a plurality of
filaments over the obstruction in a low friction mode, where the
low friction mode encounters low frictional forces over the
obstruction.
111. The method of claim 109, where translating the traversing
device comprises translating the traversing device over the
obstruction without dislocating or mobilizing the obstruction
within the blood vessel.
112. The method of claim 109, where converting the traversing
device comprises rotating a first portion of the plurality of
filaments relative to a second portion of the plurality of
filaments to wrap the plurality of filaments around the
obstruction.
113. The method of claim 109, where the plurality of wires
comprises a plurality of sets of filaments, and where rotation of
the plurality of filaments comprises rotating one set relative to
another set.
114. The method of claim 109, where advancing the obstruction
removal device comprises advancing the obstruction removal device
through the obstruction.
115. The method of claim 109, where advancing the obstruction
removal device comprises advancing the obstruction removal device
around the obstruction.
116. The method of claim 109, where the plurality of filaments
comprise a mesh of filaments.
117. The method of claim 109, where the plurality of filaments each
comprise a first and second end and where each end is attached to
at least a near connector.
118. The method of claim 117, where the connector comprises a shape
selected from an arcuate shape, a partial circular shape, a loop,
an oval, a square, a rectangle, a polygon, an overlapping loop, a
pair of semi-circles, a flower shape, and a FIG. 8.
119. The method of claim 118, where the connector has a
3-dimensional profile such that portions thereof lie in a plurality
of planes.
120. The method of claim 118, where the connector comprises a
plurality of connector sections.
121. The method of claim 117, where the connector is
discontinuous.
122. The method of claim 117, where the connector is adjustable in
size.
123. The method of claim 117, where second end is attached to at
least a far connector.
124. The method of claim 117, where the plurality of filaments
comprises a plurality of sets of filaments such that the first set
of filaments is connected to the near and far connector and where
additional sets of filaments are each connected to at least two
additional connectors.
125. The method of claim 109, where the obstruction comprises a
blood clot, plaque, cholesterol, thrombus, a naturally occurring
foreign body, a non-naturally occurring foreign body, or
combination thereof.
126. The method of claim 109, where converting the obstruction
removal device into the high friction mode comprises rotating a
near portion of the obstruction removal device relative to a far
portion of the obstruction removal device.
127. The method of claim 126, comprises rotating the near connector
while holding the far connector stationary.
128. The method of claim 126, comprises rotating the far connector
while holding the near connector stationary.
129. The method of claim 126, comprises rotating the near connector
and rotating the near connector in an opposite direction.
130. The method of claim 126, further comprising a plurality of
filaments extending from the near portion to the far portion of the
obstruction removal device, where rotating the near portion causes
the filaments adjacent to the near portion to twist and cross
proximal to the obstruction causing a section of the filaments
engaging the obstruction to apply a compressive force on the
obstruction without twisting and crossing over one another over a
length of the obstruction.
131. The method of claim 130, where rotating the portions also
causes the filaments adjacent to the far portion to twist and cross
distally to the obstruction.
132. The method of claim 126, further comprising a plurality of
filaments extending from the near portion to the far portion of the
obstruction removal device, where rotating the portions causes the
filaments to twist over the obstruction causing a compressive force
on the obstruction.
133. The method of claim 109, further comprising expanding a
balloon member adjacent to the obstruction to expand the
vessel.
134. The method of claim 109, further comprising expanding a coil
member adjacent to the obstruction to expand the vessel.
135.-167. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a non-provisional of U.S. Provisional
Application No. 60/765,496 filed Feb. 03, 2006 which is
incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The devices and methods described herein relate to clearing
of blockages within body lumens, such as the vasculature, by
addressing the frictional resistance on the obstruction prior to
attempting to translate the obstruction within the body lumen. In
one variation, the devices and methods described below may treat
conditions of ischemic stroke by remove blockages within arteries
leading to the brain. Accordingly, variations of such methods and
devices must navigate tortuous anatomy and vasculature without
causing unacceptable damage to the anatomy. Also, the devices and
methods first secure and surround the obstruction (such as a clot)
prior to significantly moving the clot within the anatomy.
BACKGROUND OF THE INVENTION
[0003] Ischemic stroke occurs when a blockage in an artery leading
to the brain causes a lack of supply of oxygen and nutrients to the
brain tissue. The brain relies on its arteries to supply oxygenated
blood from the heart and lungs. The blood returning from the brain
carries carbon dioxide and cellular waste. Blockages that interfere
with this supply eventually cause the brain tissue to stop
functioning. If the disruption in supply occurs for a sufficient
amount of time, the continued lack of nutrients and oxygen causes
irreversible cell death (infarction). Accordingly, immediate
medical treatment of an ischemic stroke is critical for the
recovery of a patient.
[0004] The infarction may not develop or may be greatly limited
given a rapid clearing of the blockage to reestablish the flow of
blood. However, if left untreated, ischemic stroke may lead to the
permanent loss of brain tissue, and can be marked by full or
partial paralysis, loss of motor control, memory loss, or
death.
[0005] Several different diseases may lead to an ischemic stroke.
Typically, deposition of cholesterol (artherosclerosis), formation
of blood clots, or other objects in the vessels may disrupt blood
flow and lead to ischemic stroke. Furthermore, the substances that
cause the blockages may break free from larger vessels outside the
brain and become lodged within narrower arteries closer to the
brain (embolism).
[0006] Ischemic stroke may be divided into thrombotic strokes and
embolic strokes. A thrombotic stroke occurs when the building and
rupturing of atheromatous plaque within the brain blocks cerebral
arteries. Clinically referred to as cerebral thrombosis or cerebral
infarction, this condition represents approximately 10% of all
strokes. An embolic stroke occurs when a clot or emboli forms
somewhere other than in the brain, such as in the cervical carotid
artery or in the heart, and travels in the bloodstream until the
clot becomes lodged and can not travel any further. When such a
condition occurs in the arteries supplying the brain, the condition
results in almost immediate physical and neurological effects.
[0007] While these are the most common causes of ischemic stroke,
there are many other possible causes. Examples include use of
drugs, trauma to the blood vessels of the neck, or blood clotting
disorders.
[0008] Apart from surgical techniques, medical practitioners could
address such blockages with the use of Tissue Plasminogen Activator
(t-PA). However, t-PA must be used within the first three hours of
the onset of stroke symptoms and may take hours or even days to
successfully restore flow. In addition, t-PA carries an increased
risk of intracerebral hemorrhage. It is currently believed that the
use of t-PA results in a 30% success rate as well as a 6% major
complication rate. In view of these limitations, the majority of
stroke patients in the U.S. do not receive t-PA treatment.
[0009] In addition, there are a number of surgical techniques used
to remove blockages. For example, an embolectomy, involves incising
a blood vessel and introducing a balloon-tipped device (such as the
Fogarty catheter) to the location of the occlusion. The balloon is
then inflated at a point beyond the clot and used to translate the
obstructing material back to the point of incision. The obstructing
material is then removed by the surgeon. Concentric Medical, Inc.
of Mountain View, Calif. supplies devices for an interventional
approach to the removal of obstructions. Concentric supplies a
Merci.RTM. Retriever system as a device based approach for the
removal of clots. This system engages and ensnares a clot. Once
captured, a balloon catheter inflates to temporarily halt forward
blood flow while the clot is withdrawn. The clot is then pulled
into the catheter and out of the body.
[0010] Typically, the existing means to remove obstructions do not
address the frictional forces that act on the obstruction during
removal of the obstruction. For example, some conventional devices
engage the clot from the distal (or downstream) side. As the device
is pulled proximally (or upstream), the device attempts to either
engulf or ensnare the clot. However, due to the consistency of the
clot and because the clot is typically well lodged within the
vessel, the act of pulling the clot in a proximal direction cause
the clot to also compress in an axial direction. This axial
compression (when viewed along the axis of the vessel) causes a
contemporaneous radial expansion of the clot (when viewed relative
to the vessel). As a result, the increase in diameter of the clot
causes an increase in the frictional forces applied against the
arterial wall. Thus, by not addressing the frictional forces acting
on the obstruction, the process of removing the clot may actually
increase the static force that would otherwise be required to
remove or translate the clot within the vessel. Unfortunately,
increasing the amount of force applied upon one side of the clot
also increases the probability of complications during the
procedure (e.g., fragmenting the clot, failing to remove the clot,
failure to fully engulf/ensnare the clot, and/or device failure)
and can cause potential damage to the surrounding vessel.
[0011] While there are other drugs and suppliers of devices for
removal of blockages, there remains a need for methods and devices
that improve the success rate and/or reduce the complication rate
in restoring flow and thereby limit the damage from an ischemic
stroke.
SUMMARY OF THE INVENTION
[0012] It should be noted that the present methods and devices may
be used to treat blockages leading to ischemic stroke as well as to
treat blockages (caused by "obstructions") within other parts of
the body (i.e., unless specifically noted, the devices and methods
are not simply limited to the cerebral vasculature). The term
obstructions may include blood clot, plaque, cholesterol, thrombus,
naturally occurring foreign bodies (i.e., a part of the body that
is lodged within the lumen), a non-naturally occurring foreign body
(i.e., a portion of a medical device or other non-naturally
occurring substance lodged within the lumen.)
[0013] In one variation of the devices described herein, the device
allows for surrounding the obstruction prior to attempting to
translate or move the obstruction within the vessel. It should be
noted that although minimal axial movement of the obstruction may
take place, the device surrounds the obstruction before such
movement causes significant distortion to the geometry of the
obstruction resulting in an increase in the static force required
to remove the obstruction from the vessel.
[0014] In another variation of the device, the device may include a
low friction mode (such as a set of parallel wires, or wires
extending axially along the lumen or vessel) that converts to an
increased friction mode (such as a compressed set of wires acting
on the obstruction or a twisted set of wires acting on the
obstruction). The increase in friction is an increase in the
friction between the obstruction and the device (as opposed to the
vessel wall. In some cases, the low friction modes is a low surface
area mode and the high friction mode is a high surface area mode.
When configured in the low friction mode, the device is better
suited to engage the obstruction without the undesirable effect of
prematurely mobilizing the obstruction or compacting the
obstruction (e.g., when wires are slid across the obstruction in a
transverse motion). Upon engaging the obstruction, the device will
conform to a high friction mode with respect to the obstruction (in
some cases the device will have an increased surface area mode).
This high friction mode permits the device to better grip the
obstruction for ultimate removal of the obstruction.
[0015] The operation of the devices and method described herein
secure the obstruction, overcome the elastic forces of the
obstruction, then remove the obstruction from the anatomy without
losing or fractionating the obstruction. In one variation of the
invention, this is accomplished by the obstruction removal device
interacting with the obstruction in the following manner: (1) the
traversing filaments traverse the obstruction by passing either
through the obstruction or between the obstruction and the vascular
wall; (2) the traversing portion is pulled proximally to engage the
surrounding portion of the device around the obstruction, the
surrounding portion engaging the obstruction without causing
significant mobilization of the obstruction; (3) the obstruction
removal device is pulled further proximally and the surrounding
portion now mobilizes the obstruction.
[0016] As shown below, variations of the devices have a
configuration that provides a path for a portion of the device to
surround the obstruction. The paths are made using traversing
filaments that allow for low frictional translation of a
surrounding portion of the device over the obstruction without
causing axial translation of the obstruction. This mechanism is
described in more detail below.
[0017] Once in the proper position, a portion of the device (e.g.,
a surrounding portion) increases the frictional contact with the
obstruction to disperse the pulling force more evenly across the
obstruction. The increase points of contact allow for removal of
the obstruction through tortuous anatomy while ensuring that the
obstruction will not escape the encapsulation.
[0018] The surrounding portion may be fabricated in a variety of
ways. For example, the surrounding portion may comprise one or more
filaments. The surrounding portion may comprise a filter/bag, a
coil, helical filament, a mesh structure, corrugated sheet, braided
filaments, single wound or crossing filaments, tubes, membranes,
films, solid wires, filled tubes, castings. Furthermore, the
surrounding portion may have one or more ports, openings, slits,
and/or holes. The surrounding portion may be made by photochemical
etching, mechanical drilling, weaving, braiding, laser cutting, or
other means.
[0019] It should be noted that reference to surrounding or securing
the obstruction includes partially and/or fully surrounding,
engulfing, encapsulating, and/or securing the obstruction. In any
case, the surrounding portion engages the obstruction prior to
translation of the obstruction within the lumen. As noted herein, a
portion of the device may convert into a surrounding section (e.g.,
when traversing wires reorient to increase the friction acting on
the obstruction). Accordingly, the traversing section converts into
a surrounding section.
[0020] The various devices described herein rely on a reduced
profile for delivery and an expanded profile for ultimate removal
of the clot. The devices, or components of the devices, may expand
when released from a constraint, which allows the device, or
component, to assume a predetermined shape. Alternatively, or in
combination, the devices may be actuated to assume the expanded
profiles. For example, the devices may be shape memory alloys that
assume a profile when reaching a predetermined temperature (e.g.,
body temperature, or another temperature via delivery of energy to
the shape memory alloy to trigger a phase change). Actuation may
also include use any expandable member (such as a coiled spring,
balloon, wedge, etc.) that mechanically or fluidly forces expansion
of the device. These modes are well known by those skilled in the
art and are intended to be within the scope of the disclosure. When
combined with the inventive concepts disclosed herein, such
combinations fall within the inventive scope of this
disclosure.
[0021] As noted above, the filaments of the invention may be used
to translate the device or may be used to form the surrounding
section. Accordingly, the filaments may be single wound or crossing
filaments, tubes, membranes, films, solid wires, filled tubes,
castings or any similar structure. Moreover, the cross section of
such filaments may vary as required (e.g., circular, oval,
rectangular, square, or any such shape.) The filaments may be
constructed from metals, polymers, composites, hydrogels,
membranes, shape memory metals, shape memory polymers, or shape
memory alloys, superelastic metals, superelastic polymers, or
superelastic alloys, or combinations thereof. The filaments may
have uniform diameters or varying diameters. The characteristics of
the filament may be selected to better suit their required
function. For example, they can be stiff, floppy, or even have
different zones of flexibility. Moreover, the filaments may be
braided or woven members, or the construction may provide that the
filaments cross at one or many points in an overlapping,
interwoven, crisscrossing or similar manner.
[0022] It should be noted that in some variations of the invention,
all or some of the filaments (used in the surrounding portion of
the device) can be designed to increase their ability to adhere to
the obstruction. For example, the filaments of the surrounding
portion may be coupled to an energy source (e.g., RF, ultrasonic,
or thermal energy) to "weld" to the obstruction. Application of
energy to the filaments may allow the surrounding portion to deform
into the obstruction and "embed" within the obstruction.
Alternatively, the filaments may impart a positive charge to the
obstruction to partially liquefy the obstruction sufficiently to
allow for easier removal. Alternatively, a negative charge could be
applied to further build thombus and nest the device for better
pulling force. The filaments may be made stickier by use of a
hydrophilic substance(s), or by chemicals that would generate a
chemical bond to the surface of the obstruction. Alternatively, the
filaments may reduce the temperature of the obstruction to congeal
or adhere to the obstruction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Each of the following figures diagrammatically illustrates
aspects of the invention. Variation of the invention from the
aspects shown in the figures is contemplated.
[0024] FIG. 1 illustrates a system for removing obstructions from
body lumens.
[0025] FIG. 2A illustrates an example of an obstruction lodged
within a body lumen.
[0026] FIGS. 2B to 2F illustrate advancement of a catheter beyond
an obstruction and placement of traversing wires around the
obstruction.
[0027] FIG. 3A illustrates an obstruction removal device once
converted to a high friction mode.
[0028] FIGS. 3B to 3E, show variations of a device having filaments
that do not cross one another over the length of the obstruction
when converted to a high friction mode.
[0029] FIG. 3F to 3G illustrate positioning a surrounding portion
and translating the surrounding portion over the obstruction.
[0030] FIGS. 3H to 3I illustrate an obstruction removal device
deployed distally to an obstruction and then translated proximally
over the obstruction.
[0031] FIGS. 4A to 4E illustrate various additional configurations
of devices able to assume a high friction mode covering over an
obstruction.
[0032] FIG. 4F illustrates a variation of a device using an end of
a catheter for converting the device to a high friction mode.
[0033] FIGS. 5A to 5B illustrate another variation of a portion of
an obstruction removal device configured to convert from a low
friction mode to a high friction mode.
[0034] FIGS. 6A to 6G illustrate various configurations of
connectors for use with obstruction removal devices.
[0035] FIGS. 6H to 6I illustrate a variation of a leading wire and
connector having an unconstrained shape that is selected to be
larger or simply different than the intended vessel to provide
increased stability upon deployment.
[0036] FIG. 7A to 7D illustrates variations in which the connector
is offset.
[0037] FIGS. 8A to 8B illustrate hooks, fibers, and/or barbs for
increasing the ability of the device to remove obstructions.
[0038] FIGS. 9A to 9C illustrate additional variations of
obstruction removal devices.
[0039] FIGS. 10A to 10H also illustrate additional variations of
obstruction removal devices, focusing mainly on variations of the
surrounding portion.
[0040] FIGS. 11A to 11C illustrate a variation where use of
mechanical expansion distends the vessel wall and loosens the
obstruction from the vessel.
DETAILED DESCRIPTION
[0041] It is understood that the examples below discuss uses in the
cerebral vasculature (namely the arteries). However, unless
specifically noted, variations of the device and method are not
limited to use in the cerebral vasculature. Instead, the invention
may have applicability in various parts of the body. Moreover, the
invention may be used in various procedures where the benefits of
the method and/or device are desired.
[0042] FIG. 1 illustrates a system 10 for removing obstructions
from body lumens as described herein. In the illustrated example,
this variation of the system 10 is suited for removal of an
obstruction in the cerebral vasculature. Typically, the system 10
includes a catheter 12 microcatheter, sheath, guide-catheter, or
simple tube/sheath configuration for delivery of the obstruction
removal device to the target anatomy. The catheter should be
sufficient to deliver the device as discussed below. The catheter
12 may optionally include an inflatable balloon 18 for temporarily
blocking blood flow or for expanding the vessel to release the
obstruction
[0043] It is noted that any number of catheters or microcatheters
maybe used to locate the catheter/microcatheter 12 carrying the
obstruction removal device (not illustrated) at the desired target
site. Such techniques are well understood standard interventional
catheterization techniques. Furthermore, the catheter 12 may be
coupled to auxiliary or support components 14, 16 (e.g., energy
controllers, power supplies, actuators for movement of the
device(s), vacuum sources, inflation sources, sources for
therapeutic substances, pressure monitoring, flow monitoring,
various bio-chemical sensors, bio-chemical substance, etc.) Again,
such components are within the scope of the system 10 described
herein.
[0044] In addition, devices of the present invention may be
packaged in kits including the components discussed above along
with guiding catheters, various devices that assist in the
stabilization or removal of the obstruction (e.g., proximal-assist
devices that holds the proximal end of the obstruction in place
preventing it from straying during removal or assisting in the
removal of the obstruction), balloon-tipped guide catheters,
dilators, etc.
[0045] FIGS. 2A to 2F show one example of the deployment of the
basic structure of connectors and traversing filaments about an
obstruction in a vessel. The figures are intended to demonstrate
the initial placement of the connectors and filaments immediately
prior to removal of the obstruction either using a filter or by
torquing, rotating and/or twisting the near connector relative to
the far connector. This action converts the device from a low
friction device to a high friction device (where the low/high
friction is the friction between the device and the obstruction).
This action may also be referred to as a low surface area mode
converting to a high surface area mode (in cases where the device
extends beyond the obstruction and relative motion between ends of
the device causes the device to shrink in axial length as it is
twisted.) In addition, the number of connectors used, the shape of
the connectors, as well as the number of filaments is intended to
be for illustrative purposes only. It is contemplated that any
variation of connector and/or filament may be deployed in a similar
manner.
[0046] FIG. 2A illustrates an example of an obstruction 2 lodged
within a body lumen or vessel 6. In the case where the vessel is a
cerebral artery, the obstruction may result in an ischemic stroke.
Using standard interventional catheterization techniques, a
microcatheter 102 and guidewire 104 traverse the obstruction. The
microcatheter 102 may be advanced through the obstruction 2.
Alternatively, the microcatheter 102 may "push" aside the
obstruction and is advanced around the obstruction. In any case,
the microcatheter 102 travels from the near end 3 (or proximal
side) of the obstruction 2 to the far end 4 (or distal side) of the
obstruction 2. It is noted that the catheter 102 may be centered or
off-center with respect to the obstruction 2. Furthermore, the
device may or may not be used with a guidewire to navigate to the
site and traverse the obstruction.
[0047] FIG. 2B shows another variation where a microcatheter 102
traverses the obstruction 2 between the wall of the vessel 6 and
the obstruction 2. As shown, the open end of the microcatheter 102
is distal to the obstruction 2 and is now positioned to deploy
devices for removal of the obstruction 2. This variation shows the
device after removal of any guidewire. However, some variations of
the device may be placed without an accompanying guidewire.
Moreover, the structures discussed herein may be directly
incorporated into a guidewire assembly where deployment may require
a sheath or other covering to release the components from
constraint.
[0048] FIG. 2C illustrates deployment of a far connector 110 from
within the microcatheter 102 distal to the obstruction 2. The far
connector 110 can be self-expanding such that it assumes, or moves
towards, the expanded profile (as shown) upon deployment from the
constraint of the microcatheter 102.
[0049] The connectors 108, 110 and/or traversing filaments 112 are
designed to expand to the wall of the vessel when released from the
catheter. This action allows the device 100 to surround the
obstruction 2 prior to attempting to dislodge it. The components of
the obstruction removal device 100 (e.g., the leading wires 106,
the connectors 108 110, the traversing filaments 112, and/or the
surrounding portion 114) may be fabricated from any biocompatible
material that permits the function as described herein. In some
variations, the material may comprise a shape memory or
super-elastic alloy such as nitinol.
[0050] FIG. 2D shows withdrawal of the microcatheter 102 to the
proximal side 3 of the obstruction 2. The spacing between the far
connector 110 and the obstruction 2 may vary. In some cases, the
far connector 110 will move closer towards the obstruction 2 during
spacing of the traversing filaments 112 as discussed below. The far
connector 110 remains in place either using the inherent friction
of the connector against the vessels and/or obstruction 2.
Alternatively, or in combination, a wire-type member (not shown)
may provide an opposing force against the connector 110 as the
catheter 102 moves proximal to the obstruction 2.
[0051] As discussed herein, the obstruction removal devices include
a plurality of filaments affixed between connectors. Since the far
connector 110 is deployed at the distal side 4 of the obstruction
2, withdrawal of the microcatheter 102 results in the plurality of
filaments 112 spanning across the obstruction 2 as shown.
[0052] FIG. 2E illustrates deployment of a near connector 108.
Although the illustrated variation depicts the near connector 108
as being deployed from within the microcatheter 102, alternative
variations of the device include a near connector 108 that is
located about the exterior of the microcatheter 102 or that is
located about another delivery device (not shown) that is external
to the microcatheter 102. In this case, the near connector 108 is
similar in profile and design to the far connector 110.
Accordingly, the near connector 108 self expands within the vessel
6 upon deployment from the microcatheter 102. In some variations of
the device, the near and far connectors 108, 110 may have different
shapes or profiles. In any case, the profile of the connectors
should be sufficient to expand the traversing wires sufficiently
within the vessel to prepare for ensnaring or encapsulation of the
obstruction 2.
[0053] FIG. 2E also illustrates a connecting or leading wire/member
106 that couples the microcatheter 102 to the near connector 108.
The term leading wire, leading member, lead wire, etc. is intended
to encompass a wire, tube, or any other structure that organizes
and sometimes houses the smaller traversing filaments and/or near
connectors described herein. Naturally, variations of the device
include a leading wire 106 that is affixed to the far connector or
the traversing wires. Moreover, the illustration depicts a single
leading wire 106. However, as noted below, the device can include a
number of traversing wire 106 affixed to the near and/or far
connectors 108, 110.
[0054] FIG. 2F illustrates spacing the traversing filaments/wires
112 from simply spanning the obstruction 2 (as depicted in FIG.
2E). This action causes the filaments 112 to span the obstruction 2
while reorienting towards an exterior of the obstruction 2. As
noted herein, the traversing filaments 112 may remain partially or
fully within the obstruction 2. However, given that the filaments
are spaced about the connectors, the filaments shall separate
radially over the obstruction allowing for the subsequent ensnaring
and removal.
[0055] Spacing the filaments may occur via a number of modes such
as tensioning, expanding, spreading separating and/or withdrawing
the filaments. In certain variations of the device, the filaments
are moveable relative to a near connector and/or a far connector.
Such a feature allows application of tension to the filaments while
keeping the connector in place. This causes the filament to enter a
state of tension for spacing about the wall of the vessel.
Alternatively, the filaments may be fixed relative to the
connectors. Upon deployment the filaments either self expand or are
actuated to space about the vessel wall for eventual translation of
the device over the obstruction. Regardless of the mode used, the
filaments are intended to be positioned at or near a surface of the
obstruction so that they can reduce the effects of any friction
between the obstruction and the lumen or vessel wall.
[0056] FIGS. 3A to 3I provide illustrations of device variations
that ensnare the obstruction 2 after the device is in the
configuration demonstrated by FIG. 2F above. FIGS. 3A, 3C, and 3E
represent variations of the device 100 after transforming from a
low friction mode to a higher friction mode for removal of the
obstruction. FIGS. 3F and 3G illustrate a variation where a
surrounding portion or filter covers the obstruction for its
ultimate removal from the body.
[0057] FIG. 3A illustrates rotation of the near connector 108
relative to the far connector 110 to ensnare the obstruction 2
within the traversing wires 112. As noted herein, either connector
may rotate while another connector remains stationary.
Alternatively, each connector may rotate with the rate of rotation
for one connector being slower than another. In yet another
variation, each connector may be rotated in opposite
directions.
[0058] Although the variation shows only four traversing wires 112
any number of wires may be used so long as the rotation converts
the traversing wires 112 into a relatively increased friction mode
as compared to the low friction mode (when the traversing wires are
in a parallel configuration). The low friction mode is represented
by FIG. 2F. FIG. 3A illustrates the obstruction removal device 100
after rotation of the sets of traversing filaments and connectors.
The result is that the obstruction 2 becomes ensnared (and/or
encapsulated) and may be removed from the body. It should be noted
that the same effect may be achieved by only rotating one connector
or set of wires while keeping the other connector or set of wires
stationary.
[0059] The rotation of the connector 108 can be performed in any
number of ways as known to those skilled in the art. However, as
shown in FIG. 3A, the lead wire 106 may comprise additional
secondary wires attached to the connector 108. So rotation of the
connector 108 may occur via rotation of the lead wire and/or
microcatheter. In any case, once the device assumes the increased
friction mode condition, the obstruction 2 can be moved laterally
within the vessel for removal.
[0060] FIGS. 3A to 3E illustrate various configurations where
relative rotation of the connectors 108, 110 convert the device
into a high friction mode. In FIG. 3A, the traversing filaments 112
twist and cross one another over the length of the obstruction 2.
However, as shown in FIGS. 3B to 3E, variations of the device 100
can have filaments 112 that do not cross one another over the
length of the obstruction 2. Although these variations are depicted
to have single connectors on each end and four filaments, the
design of the devices may vary as required by the particular
application. In addition, the variations shown in FIG. 3B to 3E are
shown without any catheter or leading wire for convenience to
better illustrate the conversion of the device from a low friction
mode to a high friction mode. Naturally, rotation of the catheter
and/or lead wire will cause relative rotation between
connectors.
[0061] In FIG. 3B, the device 100 is in a similar position as that
shown in FIG. 2E. However, FIG. 3B shows a variation of a device
100 that is is selected to have a length greater than the targeted
obstruction 2. Upon rotation, the traversing filaments 112 remain
uncrossed over the length of the obstruction 2. In some cases, the
filaments 112 may experience some twisting and will not remain
parallel. However, the filaments 112 twist at twist points 116 that
are proximal to and distal to the obstruction 2. The relative
motion of the connectors 108, 110 as well as the twist point 116
causes the filaments 112 to exert a compressive force on the
obstruction 2 without crossing one another over the length of the
construction. Accordingly, while the surface area in contact
between the filaments 112 and obstruction 2 remains relatively the
same, the compressive action of the filaments 112 onto the
obstruction converts the device 100 to a high friction mode on the
obstruction.
[0062] FIG. 3D illustrates another variation of a device in a
similar position as that shown in FIG. 2E. However, FIG. 3D shows a
variation of a device 100 that extends proximally from the near end
of the obstruction 2. The relative motion between connectors 108,
110 causes a twist point 116 that is proximal to the obstruction 2.
As with the previous variation, the twist point 116 forces the
filaments 112 against the obstruction 2 without crossing one
another over the length of the obstruction 2. As a result, the
device 100 is now in high friction mode. In some cases, the
filaments 112 may experience some twisting and will not remain
parallel.
[0063] The variation of FIGS. 3D and 3E also show the device 100 as
including a cap or cover 118 about the distal connector 110. The
cap or cover 118 may be a bag, mesh, a continuation of the
filaments 112, and/or a surrounding portion 114 as discussed
herein. The cap or cover 118 reduces the likelihood that the
obstruction is driven through the far connector 110 during
conversion of the device 100 from a low friction mode to a high
friction mode.
[0064] FIG. 3F illustrates another variation of a device where the
far connector 110 includes a filter or surrounding portion 114. In
variations of the device, the filter 114 is sufficiently permeable
to allow blood flow therethrough. As noted above, the surrounding
portion 114 may be any structure that covers, encapsulates,
engulfs, and/or ensnares the obstruction either fully or partially.
Accordingly, although the surrounding portion 114 is illustrated as
a filter/bag, the surrounding portion 114 may comprise a coil,
helical wire, a plurality of filaments, mesh structure, corrugated
sheet, braided filaments, single wound or crossing filaments,
tubes, filled tubes, castings, solid wires, membranes, films,
capturing sections, (and may include ports, openings, slits, and/or
holes made from photochemical etching, mechanical drilling) or any
other structure that may translate or remove the obstruction 2 once
the frictional component is addressed.
[0065] In this variation, the obstruction removal device 100
includes leading filaments 106 connected to a near connector 108.
In this example, the lead filament 106 may be a single wire or
filament. Alternatively, the lead filament may comprise a single
wire with a plurality of wires connecting the single wire to the
ring.
[0066] As with the above examples, the illustrated variation shows
the connector 108 as comprising a loop. However, as described
herein, the connectors may also comprise various alternate shapes
(e.g., a circle, an arcuate shape, a partial circular shape, a
loop, an oval, a square, a rectangle, a polygon, an overlapping
loop, a pair of semi-circles, a flower shape, and a FIG. 8, other
shapes, etc.) The near connector 108 is joined to a far connector
110 via a plurality of filaments 112. It is noted that the
inventive device shall include at least one, but preferably two or
more traversing filaments 112. It is further noted that the
obstruction removal device 100 may be part of or integrated with
the microcatheter 102.
[0067] FIG. 3G illustrates withdrawal of the microcatheter 102 and
the proximal translation of device 100 to place the surrounding
portion 114 over the obstruction 2. As the obstruction removal
device 100 translates proximally, the traversing filaments 112
locate towards the exterior region of the obstruction 2. As
discussed above, the connectors 108, 110 and traversing filaments
112 are designed to expand to (or near to) the perimeter of the
wall of the vessel 2 and will usually locate to an exterior of the
obstruction 2. However, variations of the device and method include
situations where the filaments locate substantially, but not fully,
towards the outer region of the obstruction. In any case, the
location of the filaments 112 will sufficiently overcome the
frictional forces discussed herein. In the illustrated variation,
the traversing filaments 112 substantially span the length of the
obstruction 2 by extending across the (proximal) 3 and (distal) 4
sides. These traversing filaments 112 provide paths for movement of
the device 100 around the obstruction 2. These paths allow for the
surrounding portion 114 to engulf the entire obstruction 2 so that
it may be removed from the vasculature and body.
[0068] FIG. 3H depicts an obstruction removal device 100 similar to
that shown in FIG. 3F. However, in this variation, the near and far
connectors 108, 110 are both deployed distally to the obstruction 2
and then translated back over the obstruction 2. As shown, this
deployment allows the traversing filaments 112 and the surrounding
portion 114 to separate prior to contacting the occlusion 2. Next,
the entire device 100 is pulled over the occlusion 2 as described
above. The variation of the device shown in FIGS. 3F and 3H
addresses the frictional forces that act between the obstruction
and the vessel wall. Conventional devices that provide a bag
attached to a wire (such as a vascular filter or distal protection
device), are typically unable to remove the obstruction because
they cannot overcome these frictional forces that lodge the clot
against the vessel wall. Typically, such conventional devices are
only designed to "catch" free floating clots. The traversing
filaments described herein are configured to be positioned
surrounding the obstruction. Their low friction with respect to the
clot and the vessel allows for positioning of the filaments without
disrupting or further compacting the clot against the vessel wall.
Once the filaments surround or are spaced about the obstruction,
they reduce the friction between the clot and vessel wall by
reducing points of contact. Once these filaments surrounded the
clot, they permit translation of the device to permit an
encapsulating section 114 to surround the obstruction for
removal.
[0069] FIG. 3I illustrates the device 100 of FIG. 3H when
translated over the obstruction 2. Eventually, the device 100 is
pulled so that the surrounding portion or blood permeable filter
114 covers the obstruction 2 (as shown in FIGS. 3F and 3G.
[0070] FIG. 4A illustrates another variation of a portion of an
obstruction removal device 120 that is able to convert from a low
friction mode covering to a higher friction mode covering. As noted
above, this variation allows the medical practitioner to engage an
obstruction with sparse coverage or low friction mode to overcome
frictional forces. Upon properly engaging the obstruction, the
device configuration allows conversion to a high friction mode for
removal of the device and obstruction.
[0071] As shown, this variation of the obstruction removal device
120 includes two sets of traversing filaments 122, 124 and
accompanying connectors 108, 110, and 126, 128. The first set 122
comprises a first near connector 108 and first far connector 110
with the accompanying traversing filaments. The second set 124
comprises the second near connector 126 and second far connector
128 with the accompanying traversing filaments 124. The second set
124 is coaxially located over the first set 122. The materials of
the components may be as described above. In any case, the
components are designed to expand to the perimeter of the vessel
wall upon release from the catheter.
[0072] FIG. 4B shows the conversion of the obstruction removal
device converting from a low friction mode (from FIG. 4A) to the
high friction mode. For example, the first near connector 108 may
be rotated relative to the second near connector 126 (where the
second near connector may remain still or it may be rotated in an
opposite direction relative to the first near connector as shown by
the arrows). As a result, the traversing filaments 122, 124 deform
in opposite directions to form a braid-type pattern increasing the
friction mode over the obstruction.
[0073] FIG. 4C illustrates another variation of an obstruction
removal device 100 in a low friction mode state. In this variation,
the device 100 includes a near connector 108, a far connector 110
with traversing filaments between the connectors 108, 110. The
device 100 also includes an additional connector 132 with
non-rotating filaments 134 extending to the far connector 110. FIG.
4D illustrates the device 100 of FIG. 4C when the near connector
108 is rotated as shown by arrow 136. However, the additional
connector 132 and associated filaments 134 do not rotate. Upon
rotation of the near connector 108 and twisting of the filaments
112, all of the filaments 112 and 134 compress the obstruction over
the length of the filaments. Such a feature creates additional
friction on the obstruction by the device.
[0074] FIG. 4E shows another variation of an obstruction removal
device 100 configured to move between low and high friction mode
states. This variation includes additional support rings 138
located between connectors 108, 110 and within the filaments 112.
The support rings keep the device 100 at a relatively constant
diameter upon assuming the increased friction mode state. The
support rings may be slightly undersized compared to the
connectors, allowing the filaments to slightly compress the
obstruction when converted to a high friction mode, but limiting
the amount of compression by limiting the resulting diameter. The
support rings 138 can be freely placed within the traversing
filaments 112. Alternatively, the rings 138 can be attached to one
or more than one filament 112 to prevent undesired migration during
deployment of the device.
[0075] FIG. 4F illustrates one example of a microcatheter 102
having a near connector 108 located externally to the catheter 102
with traversing filaments 112 extending out of the catheter and
through the connector 108. In this variation, rotation or torquing
of the catheter 102 twists the filaments 112 resulting in increased
friction mode of the filaments 112 over an obstruction. FIG. 4F
illustrates an additional connector 132 having stationary filaments
134. This variation of the device includes the external connector
108 directly coupled to a far connector (not shown.)
[0076] FIG. 5A illustrates a variation of the device 120 having
only connectors 108 at one side of the device 120. In this
variation, the device 120 may still include two sets 108, 122 of
connectors and two sets of traversing filaments 112, 124. FIG. 5B
illustrates the variation of FIG. 5A after conversion to a high
friction mode over the obstruction 2. As discussed herein, the
connectors may be other structures than loops. Moreover, variations
of the invention include connectors that may be drawn down to a
smaller size to facilitate removal from the body after securing the
obstruction. This may be accomplished by torquing the device or
part thereof, by re-sheathing part or all of the device, or by any
mechanical means designed into the features of the device itself.
Any of these actions, or combination thereof, may also serve to
compress or decrease the diameter of the obstruction itself to
facilitate removal from the body.
[0077] In another variation, the devices described herein may be
assembled or constructed in-situ. For example, components of the
device may include connectors, portions of the connectors,
traversing elements, and/or surrounding sections. Any combination
of these components can be placed in sequential fashion. Doing so
forms a completed structure from deployment of a number of
individual components. The end result is the formation of a device
as shown in the figures. Accordingly, such components of the device
may be separately deployed in a manner that requires "assembly" of
the components by a medical practitioner during the procedure.
[0078] FIGS. 6A-6G illustrate variations of the connectors 108,
110. FIG. 6A shows a loop-shaped connector 108, 110 having
attachment points 140 for the filaments (not shown). As noted
above, the connectors can be self-expanding or actuated to expand.
The connectors may be fabricated from a polymer, a shape memory
metal, polymer, or alloy, a super-elastic metal, polymer, or alloy,
or any type of acceptable medical grade alloy, polymer, or
composite structure. Also, the devices described herein can be
fabricated from solid material, sheet or film, hollow or solid or
filled rod or wire, braids, coils, etc. In the case of the polymer,
additional strength may be added by constructing a composite
layered device. For example, a hydrogel polymer with a hydrophilic
fiber net inside that acts as exoskeleton to strengthen underlying
polymer. As discussed herein, some variations of the device may
include a distal connector having a cap or cover to prevent the
obstruction from escaping as the device is removed. Furthermore,
the sizing of the connectors within the vessel can assist in
controlling relative rotation between connectors. For example, as a
connector moves towards its expanded shape and engages a vessel or
lumen wall, the rotational friction between the connector and lumen
wall may prevent rotation. Accordingly, an adjacent connector may
have a smaller expanded profile so that the connector experiences
less friction when rotated.
[0079] FIG. 6A also illustrates the connector as having attachment
points 140 for coupling the filaments to the connectors. These
attachment points may allow for movement of the filaments relative
to the connector to tension or separate the connectors (as
described above.) The filaments may also be coupled such that they
are fixed relative to the connectors. In such a case, pulling of
the lead wire will cause the entire assembly (e.g., connectors,
filaments, and/o surrounding portion) to translate through the
vessel.
[0080] FIGS. 6B through 6G show various configurations of
connectors for use in the present device. The connectors may be cut
from sheets, fabricated from wire, molded, stamped, laser cut,
photo or chemically etched, or fabricated in any other customary
manner. Moreover, the connectors 108, 110 shown may be used in the
near and/or far ends of the traversing wires. Different connector
profiles may be incorporated into the device. In most cases, as
shown, the connectors will form an arcuate shape so that they can
expand against a vessel wall without causing trauma to the vessel.
To illustrate the connector configurations, FIGS. 6B to 6E are
shown without any accompanying traversing filaments.
[0081] FIG. 6B shows a connector 108, 110 that is a loop shape as
shown above. However, alternative configurations include a
discontinuous profile, as illustrated in FIG. 6C and an overlapping
profile, as illustrated in FIG. 6D. Such constructions allows the
connector to adjust to varying diameters of body lumens. It is
noted that a device may comprise loops of either construction. It
should be also noted that although loops are shown, other
variations may work equally well. Variations of the invention
include connectors that may be drawn down to a smaller size to
facilitate removal from the body once the obstruction is secured.
This may be accomplished by torquing the device or part thereof, by
re-sheathing part or all of the device or by any mechanical means
designed into the features of the device itself. Any of these
actions, or combination thereof, may also serve to compress or
decrease the diameter of the obstruction itself to facilitate
removal from the body. In addition, the overlapping connector, as
shown in FIG. 6D, may include a sliding ring type fastener that
allows the overlapping connector loop to expand in the same
plane.
[0082] In another example, the device may be fabricated from a
polymer composite that makes up the fasteners, filaments, bags,
etc. where the polymeric composite is very floppy until it is
exposed to either the body fluids and or some other delivered
activator that causes the polymer to further polymerize or stiffen
for strength. Various coatings could protect the polymer from
further polymerizing before the device is properly placed. The
coatings could provide a specific duration for placement (e.g., 5
minutes) after which the covering degrades or is activated with an
agent (that doesn't affect the surrounding tissues) allowing the
device to increase in stiffness so that it doesn't stretch as the
thrombus is pulled out. For example, shape memory polymers would
allow the device to increase in stiffness.
[0083] FIG. 6E shows a connector 108, 110 having multiple sections
146. As noted above, the connector sections 146 are arcuate shaped
to minimize trauma to a vessel wall. However, other shapes are also
intended to be within the scope of this disclosure.
[0084] FIGS. 6B through 6G also illustrate various configurations
of leading wires 106. The connectors may have any number of leading
wires. In some variations, it may be desirable to space the leading
wires about the profile of the connector to aid in uniform movement
of the device as it is pulled over the obstruction in the
vessel.
[0085] FIG. 6F and 6G illustrate additional variations of leading
wires 106 comprising shaped wire structures that form a "c" portion
142 of the connector. In one variation, when constrained the "c"
shaped portions 142 move together to allow for delivery within the
catheter. Upon release from the catheter, the portions 142 assume
their resting shape and expand within the vessel. The connecting
portions 142 can be selected to have a size that is slightly
greater than that of the vessel. Sizing the device relative to the
target vessel may assist in placing the connecting portions 142 and
accompanying traversing wires 112 against the wall of the
vessel.
[0086] FIG. 6G shows an additional variation where a portion 144 of
a leading wire 106 also has a "c" or semi-circular shape. In this
configuration, the "c" shaped portion 144 of the leading wire 106
can also be sized relative to the target vessel. Accordingly, the
portion 144 of the leading wire 106 functions to drive the
connecting portion 142 against the vessel wall, while the shape of
the connecting portion 142 also drives the traversing wire 112
against the vessel wall.
[0087] FIG. 6H illustrates another variation of a leading wire 106
having an unconstrained shape that is selected to be larger than
the intended vessel or simply different than a cross sectional
profile of the intended vessel (i.e., not circular or tubular, but
e.g., linear or other different shape). In this variation, the
leading wire 106 has portions 144 that extend in opposite
directions. This configuration is intended for illustrative
purposes only. Variations include connecting portions pointing in
an orthogonal direction from the main lead wire 106, oblique,
parallel (as shown), or a combination thereof. In any case, the
unconstrained shape is intended to have a larger profile or size
than the intended vessel. Moreover, the unconstrained shape may
have an entirely different profile than the intended vessel. As
shown in the figures, the profile of the device extends radially
from the vessel. So when the device and leading wire are released,
the leading wire attempts to return to the unconstrained shape. In
those variations where the unconstrained shape is different from
the circular profile of the vessel, the leading wire assumes a
shape that accommodates the vessel but is more rigid and stable
since its unconstrained shape is entirely different from that of
the vessel.
[0088] FIG. 6I shows the same device of FIG. 6H when released from
a microcatheter, sheath, or tube when in the vessel. Once released,
the leading wire 106 and accompanying portions 144 attempt to
revert to the unconstrained shape (as shown in FIG. 6H). However,
the vessel 6 restrains the leading wire 106 and portions 144 such
that the portions 144 act on the walls of the vessel. This feature
allows for improved stability when deploying the leading wires and
attached connectors and filaments within the vessel.
[0089] FIGS. 7A through 7C illustrate variations of connectors 108,
110 where the connector portions are axially spaced by an offset
152. One benefit of placing the connector portions 142, 146 in
different planes is that the device may be delivered via a smaller
microcatheter because the connector portions may be collapsed to a
smaller diameter. FIG. 7A illustrates an offset 152 between
connector portions 142 where each portion 142 is coupled to leading
wires 148, 150 of varying lengths. FIG. 7B illustrates connector
portions 146 spaced axially along a leading wire 106 to provide a
gap 152. FIG. 7C illustrates a connector 108, 110 having multiple
components 146 where one or more components is axially spaced to
provide a gap 152. FIG. 7D shows a variation 108, 110 having a
flower shape where each connector portion 146 is non-planar such
that the gap 152 occurs over the length of the connector portion
146.
[0090] Another aspect applicable to all variations of the devices
is to configure the devices (whether the traversing filament or the
surrounding portion) for better adherence to the obstruction. One
such mode includes the use of coatings that bond to certain clots
(or other materials causing the obstruction.) For example, the
traversing filament and/or surrounding portion may be coated with a
hydrogel or adhesive that bonds to a thrombus. Accordingly, as the
surrounding portion covers the clot, or as the device twists about
the clot, the combination of the additive and the mechanical
structure of the device may improve the effectiveness of the device
in removing the obstruction.
[0091] Such improvements may also be mechanical or structural. For
example, as shown in FIG. 8A, the traversing members may have
hooks, fibers, or barbs 154 that grip into the obstruction when the
device converts to a high friction mode. The hooks, fibers, or
barbs 154 may also be incorporated into the surrounding portion.
However, it will be important that such features do not hinder the
ability of the practitioner to remove the device from the body. For
example, FIG. 8B illustrates a magnified view of the area 8B from
FIG. 8A. As illustrated, the barbs may be configured such that
rotation in a particular direction causes the barbs to adhere to
the obstruction. Such a configuration could also allow lateral
movement without the barbs interfering with the vessel.
[0092] In addition to additives, the device can be coupled to an RF
or other power source (such as 14 or 16 in FIG. 1), to allow
current, ultrasound or RF energy to transmit through the device and
induce clotting or cause additional coagulation of a clot or other
the obstruction.
[0093] The methods described herein may also include treating the
obstruction prior to attempting to remove the obstruction. Such a
treatment can include applying a chemical or pharmaceutical agent
with the goal of making the occlusion shrink or to make it more
rigid for easier removal. Such agents include, but are not limited
to chemotherapy drugs, or solutions, a mild formalin, or aldehyde
solution.
[0094] Although not illustrated, the devices and methods described
herein may also be useful in removing obstructions lodged within
bifurcations in the anatomy. Generally, bifurcations greatly
increase the frictional forces on the obstructions since the
obstruction tends to be lodged in both branching sections of the
bifurcation. In such cases, the use of the presently described
devices and methods may also include an additional "puller" device
that advances beyond the portion of the obstruction partially
located in the bifurcated vessel.
[0095] As for other details of the present invention, materials and
manufacturing techniques may be employed as within the level of
those with skill in the relevant art. The same may hold true with
respect to method-based aspects of the invention in terms of
additional acts that are commonly or logically employed. In
addition, though the invention has been described in reference to
several examples, optionally incorporating various features, the
invention is not to be limited to that which is described or
indicated as contemplated with respect to each variation of the
invention.
[0096] FIGS. 9A through 9C illustrate additional variations of
obstruction removal devices. In these variations, the traversing
filaments 112 may comprise a mesh of wires or single connector.
FIGS. 9A to 9B illustrate a variation in which the connector 108
comprises a wire rather than a loop. However, the filaments and
connectors should be configured to expand to the perimeter of the
vessel wall as described previously.
[0097] FIGS. 10A-10H illustrate various additional embodiments of
obstruction removal devices 130 according to the present invention.
In these variations, the connector 108 may form a rigid wire or
hard polymer to assist in placement of the device 130. The
surrounding portion 132 may be fabricated from less rigid filaments
that increase the point of contact with the obstruction. The
surrounding portion may also have filaments that undergo a phase
change from non-rigid (or less rigid) to rigid.
[0098] It should be noted that any number of traversing filaments
112 or sets may be used in these variations.
[0099] In additional aspect of the invention, as shown in FIG. 11A
to 11C, the methods and or devices may include expansion of the
vessel wall adjacent to the obstruction either with a balloon,
coil, or similar mechanical expansion means, drugs, fluids, etc.
Such an improvement may aid where the obstruction expands part of
the vessel wall thereby increasing the amount of force required for
displacement. By distending the vessel wall as described above, the
forces on the obstruction may be reduced allowing for ease of
removal. FIG. 11A illustrates an obstruction 2 embedded within the
vessel 6. FIGS. 11B to 11C illustrate variations where use of a
coil (FIG. 11B) or a non-distensible balloon 162 (FIG. 11C)
proximal to the obstruction 2 distends the vessel wall to loosen
the obstruction 2 from the vessel. Accordingly, devices (whether
described herein or other conventional devices) may then remove the
obstruction 2.
[0100] In those variations with a mechanical expansion means, the
expansion means may be located on the delivery catheter of the
obstruction removal device, on a wire member of the device, and/or
on a separate catheter or wire used in combination with the first
delivery catheter. However, variations of such configurations are
within the scope of the invention.
[0101] In addition, devices and methods described herein may also
use balloons proximal to the obstruction to stop or slow blood flow
thereby preventing the blood from dislodging part or all of the
obstruction.
[0102] Various changes may be made to the invention described and
equivalents (whether recited herein or not included for the sake of
some brevity) may be substituted without departing from the true
spirit and scope of the invention. Also, any optional feature of
the inventive variations may be set forth and claimed
independently, or in combination with any one or more of the
features described herein. Accordingly, the invention contemplates
combinations of various aspects of the embodiments or combinations
of the embodiments themselves, where possible. Reference to a
singular item, includes the possibility that there are plural of
the same items present. More specifically, as used herein and in
the appended claims, the singular forms "a," "and," "said," and
"the" include plural references unless the context clearly dictates
otherwise.
* * * * *