U.S. patent application number 12/009378 was filed with the patent office on 2008-05-22 for heart valve chord cutter.
Invention is credited to Daniel L. Cox.
Application Number | 20080119882 12/009378 |
Document ID | / |
Family ID | 39059450 |
Filed Date | 2008-05-22 |
United States Patent
Application |
20080119882 |
Kind Code |
A1 |
Cox; Daniel L. |
May 22, 2008 |
Heart valve chord cutter
Abstract
A medical device and method for percutaneously treating a heart
valve. In one embodiment, the medical device includes a catheter
having a proximal portion, a distal portion, and a notch formed
near the distal portion. A cutting element may be disposed within
the distal portion and is moveable across the notch to slice
through a heart chord.
Inventors: |
Cox; Daniel L.; (Palo Alto,
CA) |
Correspondence
Address: |
GUIDANT CORPORATION, INC./BLAKELY
1279 OAKMEAD PARKWAY
SUNNYVALE
CA
94085-4040
US
|
Family ID: |
39059450 |
Appl. No.: |
12/009378 |
Filed: |
January 17, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10295383 |
Nov 15, 2002 |
7331972 |
|
|
12009378 |
Jan 17, 2008 |
|
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Current U.S.
Class: |
606/171 |
Current CPC
Class: |
A61B 17/32075 20130101;
A61B 2017/32004 20130101; A61B 17/320783 20130101; A61B 17/320016
20130101; A61B 2017/00243 20130101; A61B 2017/003 20130101 |
Class at
Publication: |
606/171 |
International
Class: |
A61B 17/32 20060101
A61B017/32 |
Claims
1. A kit for treating a heart valve, the kit comprising: a first
catheter having a cutting element, said first catheter having a
size and shape to be percutaneously advanced and positioned
relative to a heart valve chord, said cutting element for cutting
through said heart valve chord; a second catheter having a support
member which is released from said second catheter, said support
member being deployed percutaneously by said second catheter to at
least one of a region of a mitral valve or a region of a coronary
sinus adjacent to said mitral valve.
2. The kit of claim 1, further comprising instructions for using
said kit.
3. The kit of claim 1, wherein said cutting element is disposed
near a notch in a distal portion of said first catheter and wherein
said support member reshapes a mitral valve annulus.
4. A method for cutting a heart valve chord, the method comprising:
advancing a cutting element disposed with a catheter to said heart
valve chord percutaneously; positioning said heart valve chord
relative to said cutting element; cutting through said heart valve
chord with said cutting element.
5. The method of claim 4, wherein cutting further comprises
operating a control mechanism coupled to said cutting element.
6. The method of claim 5, wherein positioning further comprises
steering said catheter with said control mechanism.
7. The method of claim 4, wherein advancing further comprises
placing said catheter in a left ventricle of a patient's heart.
8. The method of claim 7, wherein positioning further comprises
placing a mitral valve chordae relative to said cutting
element.
9. A method for treating a heart valve, the method comprising:
advancing a cutting element disposed with a catheter to a heart
valve chord percutaneously; positioning said heart valve chord
relative to said cutting element; cutting through said heart valve
chord with said cutting element; deploying percutaneously a support
member to at least one of a region of a mitral valve or a region of
a coronary sinus adjacent to said mitral valve.
10. The method of claim 9, wherein said cutting element is disposed
near a notch in a distal portion of said catheter and wherein said
support member reshapes a mitral valve annulus.
11. The method of claim 10, wherein said deploying comprises
advancing said support element with a second catheter.
12. A method for cutting a heart valve chord, the method
comprising: advancing a cutting element disposed within a catheter
to said heart valve chord percutaneously, said catheter having a
notch formed therein; positioning said heart valve chord within
said notch; actuating said cutting element across said notch to
slice through said heart valve chord.
13. The method of claim 12, wherein actuating further comprises
retracting said cutting element from a first position distal to
said notch to a second position proximal to said notch.
14. The method of claim 13, wherein actuating further comprises
operating a control mechanism coupled to said cutting element.
15. The method of claim 14, wherein positioning further comprises
steering said catheter with said control mechanism.
16. The method of claim 12, wherein advancing further comprises
placing said catheter in a left ventricle of a patient's heart.
17. The method of claim 16, wherein positioning further comprises
placing a mitral valve chordae within said notch.
Description
[0001] The present application is a divisional of co-pending U.S.
application Ser. No. 10/295,383, filed Nov. 15, 2002.
TECHNICAL FIELD
[0002] The disclosure, in one embodiment, relates generally to the
treatment of heart related diseases, and more particularly, in one
embodiment, to the treatment of defective heart valves.
BACKGROUND
[0003] FIG. 1A illustrates a heart 10 with a partial internal view
and arrows indicating the direction of blood flow within the heart.
Four valves in the heart 10 direct the flow of blood within the
left and right sides of the heart. The four valves include a mitral
valve 20, an aortic valve 18, a tricuspid valve 60, and a pulmonary
valve 62 as illustrated in FIG. 1A. The mitral valve 20 is located
between the left atrium 12 and the left ventricle 14. The aortic
valve 18 is located between the left ventricle 14 and the aorta 16.
These two valves direct oxygenated blood coming from the lungs,
through the left side of the heart, into the aorta 16 for
distribution to the body. The tricuspid valve 60 is located between
the right atrium 22 and the right ventricle 24. The pulmonary valve
62 is located between the right ventricle 24 and the pulmonary
artery 26. These two valves direct de-oxygenated blood coming from
the body, through the right side of the heart, into the pulmonary
artery 26 for distribution to the lungs, where it again becomes
re-oxygenated and distributed to the mitral valve 20 and the aortic
valve 18.
[0004] The heart valves are complex structures. Each valve has
"leaflets" that open and close to regulate the direction of blood
flow. The mitral valve 20 has two leaflets and the tricuspid valve
60 has three leaflets. The aortic 18 and pulmonary 62 valves have
leaflets that are referred to as "cusps," because of their
half-moon like shapes. The aortic 18 and pulmonary 62 valves each
have three cusps.
[0005] During diastole, the leaflets of the mitral valve 20 open,
allowing blood to flow from the left atrium 12 to fill the left
ventricle 14. During systole, the left ventricle 14 contracts, the
mitral valve 20 closes (i.e., the leaflets of the mitral valve 20
re-approximate), and the aortic valve 18 opens allowing oxygenated
blood to be pumped from the left ventricle 14 into the aorta 16. A
properly functioning mitral valve 20 allows blood to flow into the
left ventricle and prevents leakage or regurgitation of blood back
into the left atrium (and subsequently back into the lungs). The
aortic valve 18 allows blood to flow into the aorta 16 and prevents
leakage (or regurgitation) of blood back into the left ventricle
14. The tricuspid valve 60 functions similarly to the mitral valve
20 to allow deoxygenated blood to flow into the right ventricle 24.
The pulmonary valve 62 functions in the same manner as the aortic
valve 18 in response to relaxation and contraction of the right
ventricle 24 (i.e., to move de-oxygenated blood into the pulmonary
artery 26 and subsequently to the lungs for re-oxygenation).
[0006] During relaxation and expansion of the ventricles 14, 24,
(i.e., diastole), the mitral 20 and tricuspid 60 valves open, while
the aortic 18 and pulmonary 62 valves close. When the ventricles
14, 24, contract (i.e., systole), the mitral 20 and tricuspid 60
valves close and the aortic 18 and pulmonary 62 valves open. In
this manner, blood is propelled through both sides of the heart (as
indicated by the arrows of FIG. 1A). The chordae tendineae are
tendons linking the papillary muscles to the tricuspid valve in the
right ventricle and the mitral valve in the left ventricle. As the
papillary muscles contract and relax, the chordae tendineae
transmit the resulting increase and decrease in tension to the
respective valves, helping them to open and close properly. The
chordae tendineae are string-like in appearance and are sometimes
referred to as "heart strings." FIG. 1B illustrates an enlarged
view of the mitral valve region of the heart with leaflets 25, 26
forming a coapted surface to prevent backflow of blood into the
right atrium 12 from the left ventricle 14. Leaflet 26 is tethered
by chordae 30, 31 to papillary muscle 27, and leaflet 25 is
tethered by chordae 32, 33, and 34.
[0007] Regurgitation is a condition in which leaflets of a heart
valve do not close completely, resulting in the backflow of blood.
For instance, in a condition typically referred to as mitral valve
regurgitation, the leaflets of the mitral valve do not close
completely during systole and blood leaks back into the left
atrium. Studies have shown that one effect of mitral valve
regurgitation is the distortion or displacement of the left
ventricle, as well as the papillary muscles to which the mitral
valve leaflets are attached by the chordae. Displacement of the
papillary muscles away from the mitral valve annulus tethers the
leaflets into the left ventricle, thereby preventing the leaflets
from closing effectively. FIG. 1C illustrates an enlarged view of
the heart as shown by FIG. 1B, but with papillary muscle 27
displaced further down in left ventricle 14. Because of the
displacement of papillary muscle 27, chordae 34 pulls on leaflet 25
eliminating the coapting surface between the leaflets. This allows
oxygenated blood to flow back into the left atrium 12, and the
heart is then forced to work harder to pump enough oxygenated blood
to the body. This may lead to heart damage over a period of time.
Regurgitation is common, occurring in approximately 7% of the
population. Mitral valve regurgitation may be caused by a number of
conditions, including genetic defects, infections, coronary artery
disease (CAD), myocardial infarction (MI), or congestive heart
failure (CHF).
[0008] Faulty or defective valves may be treated with various
surgical procedures. Annuloplasty, for example, reduces the annular
size of the mitral valve by placing a synthetic ring around the rim
of the mitral valve. These types of procedures are typically major,
invasive surgical procedures that may require opening the chest by
sternotomy, making incisions in the chest wall, heart-lung bypass
and suspending the beating of the heart. These invasive procedures
subject patients to a tremendous amount of pain and discomfort and
require lengthy recovery and/or hospitalization periods. Patients
with congestive heart failure may not be able to tolerate the
surgical procedures, leaving them with little or no alternative to
treat their defective heart valves. Moreover, reducing the annular
size alone may still leave the patient with regurgitation symptoms
because the mitral valve leaflet may still be tethered by chordae
to the displaced papillary muscles and ventricular walls.
SUMMARY OF THE DISCLOSURE
[0009] A medical device and method for percutaneously treating a
heart valve is described. In one embodiment, the medical device
includes a catheter having a proximal portion, a distal portion,
and a notch formed near the distal portion. A cutting element may
be disposed within the distal portion and is moveable across the
notch to slice through a heart chord.
[0010] Additional embodiments, features and advantages of the
medical device will be apparent from the accompanying drawings, and
from the detailed description that follows below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present disclosure is illustrated by way of example, and
not limitation, in the figures of the accompanying drawings in
which:
[0012] FIG. 1A illustrates a heart.
[0013] FIG. 1B illustrates an enlarged view of the mitral valve
region of a heart.
[0014] FIG. 1C illustrates another enlarged view of the mitral
valve region of the heart.
[0015] FIG. 2 illustrates a side view of a medical device that may
be used to cut a heart chord percutaneously.
[0016] FIG. 2A illustrates a cross-sectional view of the device
illustrated in FIG. 2.
[0017] FIG. 2B illustrates a cross-sectional view of the device
illustrated in FIG. 2.
[0018] FIG. 2C illustrates a cross-sectional view of the device
illustrated in FIG. 2.
[0019] FIGS. 3A-3D illustrate one exemplary embodiment of the
mechanical action of a cutting element disposed within a medical
device.
[0020] FIGS. 4A-4B illustrate one embodiment of steering tendons
disposed within a catheter to provide steering capabilities.
[0021] FIGS. 5A-5D illustrate alternative embodiments of steering
tendons disposed within a catheter.
[0022] FIGS. 6A-6C illustrate side views of alternative embodiments
for a cutting element that may be disposed within a medical
device.
[0023] FIGS. 7A-7C illustrate side views of alternative embodiments
for notch designs that may be formed within a distal portion of a
medical device.
[0024] FIGS. 8A-8D illustrate cross sectional views of alternative
embodiments for a groove that may be formed within a medical
device.
[0025] FIGS. 9A-9B illustrate an alternative embodiment for
preventing rotation of a cutting element disposed within a
catheter.
[0026] FIGS. 10A-10D illustrate one exemplary method for cutting a
mitral valve chordae tendineae percutaneously.
[0027] FIGS. 11A-11B illustrate one embodiment of a medical device
to treat a heart valve.
[0028] FIGS. 12A-12B illustrate one embodiment of performing a
combination of percutaneous procedures.
DETAILED DESCRIPTION
[0029] In the following description, numerous specific details are
set forth such as examples of specific materials or components in
order to provide a thorough understanding of the present
disclosure. It will be apparent, however, to one skilled in the art
that these specific details need not be employed to practice the
disclosure. In other instances, well known components or methods
have not been described in detail in order to avoid unnecessarily
obscuring the present disclosure. Embodiments of a medical device
discussed below are described with respect to the treatment of a
mitral valve. It may be appreciated, however, that other heart
valves or body tissue may be treated, and embodiments of the
medical device are not limited in their applicability to treating
the mitral valve.
[0030] Embodiments of a medical device and methods for treating the
mitral valve percutaneously are described. A medical device, in one
embodiment, may be used to treat mitral valve regurgitation or
prolapse by severing a mitral valve chordae tendineae that prevents
the proper closing of a mitral valve leaflet during systole. In one
embodiment, the medical device includes an elongated catheter
having a proximal portion and a distal portion. The distal portion
may have a notch or an aperture window appropriately sized for
positioning a cardiac tissue or heart valve chord (e.g., a chordae
tendineae tethered to a mitral valve leaflet) therein. A cutting
element may be disposed within a lumen formed within the elongated
catheter and positioned near the distal portion. The cutting
element may be moved or actuated across the notch to slice through
the cardiac tissue (e.g., one or more selected chordae) positioned
within the notch. In one embodiment, the cutting element may be a
sharp blade. In another embodiment, the blade may be coupled to a
control mechanism disposed near a proximal portion of the catheter
and outside of a patient. The control mechanism may be handled by
an operator to move the blade back and forth across the notch. In
one embodiment, the blade may slice through a cardiac tissue by a
retracting action that moves the blade from a first position distal
to the notch to a second position proximal to the notch. In an
alternative embodiment, a cutting element may be disposed
internally in a catheter and be moved through a slot in the
catheter wall to a position outside of the catheter, thereby
allowing the cutting element to cut one or more selected chordae.
In this alternative embodiment, the catheter does not include a
notch.
[0031] In one method for treating mitral valve prolapse caused by
an elongated chordae tendineae, the chordae may be severed with a
medical device that is percutaneously advanced to the target
chordae. The medical device may include an elongated catheter
having a proximal portion and a distal portion, with a notch formed
near the distal portion for securing the medical device to the
chordae. A cutting element may be disposed within the catheter near
the distal portion, and moveable across the notch to slice through
the chordae. In one embodiment, the distal portion of the elongated
catheter may be inserted into a patient through, for example, the
femoral artery, down the aortic valve, and into the left ventricle.
The medical device may also include a control mechanism disposed
near the proximal portion of the catheter that has one or more
handles for steering the distal portion of the catheter for
advancement into the left ventricle. In one embodiment, one or more
steering tendons may extend from the control mechanism to the
distal portion of the catheter to provide steerability to the
catheter. The control mechanism may also include a separate handle
coupled to a wire that extends from the handle and coupled to the
cutting element. The handle may by used to cause a forward or
reverse movement of the cutting element across the notch to slice
through the chordae. In one embodiment, the cutting element, which
may be a blade, may be retracted from a first position distal to
the notch to a second position proximal to the notch using a handle
disposed on a control mechanism. This exemplary embodiment provides
an advantage of percutaneously treating mitral valve prolapse
without the need for invasive surgical procedures.
[0032] Referring now to FIGS. 11A-11B, side and top views of one
embodiment of a medical device to treat a heart valve are
illustrated. Medical device 1100, in one embodiment, may be used to
cut one or more heart chords (e.g., a mitral valve chordae)
percutaneously. FIG. 11A shows a side view of medical device 1100
having a proximal portion 1110, an elongated catheter portion 1105,
and a distal portion 1120. Elongated catheter portion 1105 is not
drawn to scale and may be of an appropriate length to reach a
target region within a patient. Elongated catheter may be
substantially tubular and may be appropriately sized to fit within
lumens of a patient (e.g., arteries and vessels). Proximal portion
1110 includes a control mechanism 1112 having one or more handles
or control elements (e.g., handle 1114). Distal portion 1120
includes a notch 1122 formed into the catheter body. A top view of
medical device 1100, as illustrated by FIG. 11B, shows notch 1122
having a width substantially similar to a diameter of catheter
1105. The opening formed by notch 1122 also shows a wire 1130
disposed within catheter 1105. As described in greater detail
below, wire 1130, in one embodiment, may be coupled at one end to a
cutting element (not shown) disposed near the distal portion 1120,
and to a handle (e.g., handle 1115) at the opposite end. When a
heart chord (e.g., mitral valve chordae) is positioned across notch
1122, a cutting element (e.g., a blade) may be moved from one side
of the notch to the opposite side of the notch, in a direction of
the elongated catheter, to slice through or cut the chord. Control
mechanism 1112 disposed near proximal portion 1110 may have one or
more handles (e.g., handles 1114, 1115, 1116) to provide
operability to medical device 1100, including steerability of
distal portion 1120 and the actuation of the cutting element back
and forth across notch 1122.
[0033] FIG. 2 illustrates another side view of a medical device 200
that may be used to cut a heart chord percutaneously. An enlarged
view of distal portion 220 shows notch 222 formed within catheter
205. Notch 222 has a first proximal side 260 and a second distal
side 262 along a longitudinal length of catheter 205. A lumen 235
is also formed within catheter 205 extending down to the distal
portion 220. A cutting element 240 may be disposed within lumen
235. In one embodiment, cutting element 240 may include a blade
portion 242 that may be partially covered by blade support 245.
Blade support 245 may provide rigidity and mechanical support to
blade portion 242 when slicing through a heart chord and may also
protect heart tissue from the back side of the blade. In may be
appreciated by one of skill in the art that cutting element 240 may
only include blade portion 242, without blade support 245. In one
embodiment, cutting element 240 may be made of a uniform material,
including various types of metal that may be contemplated for a
blade (e.g., stainless steel). Alternatively, blade support 245 and
blade portion 242 may be made of different materials. For example,
blade portion 242 may be made of stainless steel, and blade support
may be made of a polymer.
[0034] In one embodiment, cutting element 240 may be positioned
near the distal side 262 of notch 222 (as shown in FIG. 2) such
that no portion of cutting element (e.g., blade portion 242 or
blade support 245) extends out into notch 222. Blade support 245
may be coupled to a wire 230 that extends to proximal portion 210
and that is coupled to control mechanism 212. Distal portion 220
also shows a steering tendon 270 extending to a point near proximal
side of notch 222. Steering tendon 270 may be coupled to an inner
surface of catheter 205 within lumen 235. Steering tendon 270
enables distal portion 220 to be steered and flexed to a desired
orientation. In one embodiment, steering tendon 270 may be
controlled by a handle disposed on a control mechanism (e.g.,
control mechanism 212). Distal portion 220 may have multiple
steering tendons disposed therein. Steering tendons are well known
in the art; accordingly, a detailed description is not provided. An
optional guidewire lumen 250 may also be formed within catheter 205
which may be used to advance a guidewire 252 therethrough. As
described in greater detail below, guidewire 252 may be used to
percutaneously advance distal portion 220 of device 200 to a region
in the patient's heart.
[0035] An enlarged view of proximal portion 210 shows catheter 205
coupled to control mechanism 212. Control mechanism includes
handles 214, 215, 216. In one embodiment, handle 214 may be coupled
to steering tendon 270, handle 216 may be coupled to a second
steering tendon 272, and handle 215 may be coupled to wire 230.
Handles 214, 215, 216 may be moved forwards and backwards within
slots formed on control mechanism 212. For example, handle 215 may
be moved forwards and backwards to move cutting element 240 across
notch 222. In an alternative embodiment, handles 214, 216 that
control steering tendons 270, 272, respectively may be knobs that
rotate to produce a steering effect of tendons 270, 272.
[0036] FIG. 2A illustrates a cross-sectional view of device 200
taken along line A-A near distal portion 220. This view of device
200 near proximal side 260 of notch 222 has lumen 235 formed within
catheter 205. Lumen 235 has a hemi-spherical shape with steering
tendons 270, 272 attached to an inner surface of catheter 205
within lumen 235. Wire 230 sits in a groove 232 formed within lumen
235. Groove 232 may be sized to secure wire 230 therein, and to
prevent wire 230 from freeing itself and releasing into lumen 235.
Catheter 205 also has a guidewire lumen 250 for advancing a
guidewire 252 therein. FIG. 2B illustrates a cross-sectional view
of device 200 taken along line B-B of FIG. 2A between a proximal
side 260 and a distal side 262 of notch 222. This part of device
200 does not have lumen 235 formed by catheter 205. Groove 232
which secures wire 230, as well as guidewire lumen 250 having
guidewire 252 disposed therein, extend through this part of device
200. FIG. 2C illustrates a cross-sectional view of device 200 taken
along line C-C of FIG. 2A near distal side 262 of notch 222.
Catheter 205 forms lumen 235 with cutting element 240 positioned
therein. In one embodiment, lumen 235 distal to notch 222 may be
narrowed to form slightly wider than groove 232. The shape and size
of lumen 235 distal to notch 222 prevent cutting element 240 from
tilting when positioned within the distal portion 220 of catheter
205. Alternatively, lumen 235 near distal to notch 222 may be
formed substantially similar to the view shown in FIG. 2C. Blade
support 245 partially covers blade portion 242 of cutting element
240, with blade support 245 sitting in groove 232. The nearly
closed shape of groove 232 enables cutting element to remain
upright. As described in greater detail below, groove 232 may have
alternative designs to support cutting element 240. Guidewire lumen
250 having guidewire 252 also extends through this part of device
200.
[0037] FIGS. 3A-3D illustrate one exemplary embodiment of the
mechanical action of a cutting element disposed within a medical
device (e.g., device 200 described above). FIG. 3A illustrates a
side view of a distal portion 300 of catheter 305 with a heart
chord 390 (e.g., a mitral valve chordae) positioned within a notch
322 formed within catheter 305. Notch 322 has a first proximal side
360 and a second distal side 362 with chord 390 positioned between
them. Cutting element 340 is disposed within catheter 305 and
positioned near distal side 362 of notch 322. Cutting element 340
includes a blade portion 342 partially covered by blade support
345. In one embodiment, blade portion 342 may be slightly curved,
although as described in greater detail below, alternative designs
for blade portion 342 may be used. Blade support 345 may extend
from the distal side 362 to the proximal side 360 of notch 322, and
coupled to wire 330. In an alternative embodiment, blade support
345 may be relatively short, and not extend a length from a distal
side 362 to a proximal side 360 of notch 322. By pulling on wire
330 (e.g., with a handle on a control mechanism 212), cutting
element 340 may be retracted from a position near distal side 362
of notch 322 to the proximal side 360. In doing so, blade portion
342 slices through chord 390, as illustrated by FIG. 3B. Cutting
element 340 may then be returned near distal side 362 of notch 322
to perform another cutting procedure (e.g., to cut another
chord).
[0038] FIG. 3C illustrates a top view of distal portion 300 of
catheter 305. The view shown may be that of cutting element 340
positioned near a distal side 362 of notch 322 illustrated in FIG.
3A. A groove 332 extends within catheter 305 of distal portion 300.
In one embodiment, groove 332 serves as track for cutting element
340 to move longitudinally within catheter 305. As discussed above,
groove 332 may be shaped to secure blade support 345 and wire 330.
As shown in FIG. 3D, cutting element 340, with blade portion 342,
is retracted linearly within catheter 305 along groove 332 to slice
through chord 390.
[0039] As described above, embodiments of a medical device
described herein may have steering capabilities to advance a
cutting element disposed within a distal portion of a catheter to a
target region in a patient's heart. FIGS. 4A-4B illustrate one
embodiment of steering tendons disposed within the catheter to
provide steering capabilities. FIG. 4A shows a top view of a distal
portion 400 of catheter 405. Tendons 470, 472 extend within an
inner surface of catheter 405 from a point proximal to notch 422
back to control mechanism 412 that may be disposed near a proximal
portion of catheter 405. A cutting element 440 is positioned distal
to notch 422 and may be moved in the manner described above,
relative to notch 422 to cut a chord. Tendon 470 may be coupled to
handle 413 and tendon 472 may be coupled to handle 416. Handle 413
may include lever 415 slidable along slot 414, and handle 416 may
include lever 418 slidable along slot 417. In one embodiment,
sliding lever 415 along slot 414 may pull tendon 470 to steer
distal portion 400 of catheter 405 in a particular direction.
Analogously, sliding lever 418 along slot 417 may pull tendon 472
to steer distal portion 400 of catheter 405 in a direction opposite
to that steered by tendon 470. FIG. 4B shows one embodiment of a
range of motion of distal portion 400 that may achieved by pulling
on tendons 470, 472 with handles 413, 416 disposed on control
mechanism 412. Control mechanism 408 may also include a knob 408
that enables catheter 405 to be rotated about a longitudinal axis.
The ability to rotate distal portion 400, along with the steering
abilities provided by steering tendons 470, 472 enables an operator
to position a heart chord within notch 422.
[0040] FIGS. 5A-5D illustrate alternative embodiments of steering
tendons disposed within a catheter 405. As illustrated by these
cross-sectional views, the number of tendons and the position of
the tendons within catheter 405 may be variable, and not limited to
the two tendons (470, 472) described above. Tendons (e.g., tendons
470, 472, 474, 476) may be disposed in different orientations with
respect to groove 432 formed within catheter 405. For example, the
use of four tendons as shown by FIG. 5D may provide the maximum
amount of steerability to catheter 405. In one embodiment, each
tendon shown in FIG. 5D may be coupled to individual control
handles on control mechanism 412.
[0041] FIGS. 6A-6C illustrate side views of alternative embodiments
for a cutting element that may be disposed within embodiments of a
medical device described herein (e.g., cutting element 340
described with respect to FIG. 3 or cutting element 240 of FIG. 2).
For example, FIG. 6A illustrates cutting element 600A with blade
support 645A forming a slot with a cutting edge of blade portion
642A extending from a top portion of the slot to a bottom portion
of the slot, but substantially disposed within the slot. FIG. 6B
illustrates cutting element 600B with blade support 645B forming a
smaller slot compared to the slot formed by the embodiment of FIG.
6A. Cutting edge of blade portion 642B extends from an outer end of
a top portion of blade support 645B to an inner end of bottom
portion of blade support 645B. FIG. 6C illustrates yet another
embodiment of cutting element 600C with blade support 645C forming
a slot analogous to that formed by blade support 645B of FIG. 6B.
Blade portion 642C forms two cutting edges extending along a top
portion and a bottom portion of blade support 645C.
[0042] FIGS. 7A-7C illustrate side views of alternative embodiments
for notch designs that may be formed within a distal portion of a
medical device to cut heart chords (e.g., notch 322 described with
respect to FIG. 3). For example, FIG. 7A shows a notch 722A having
a substantially square design formed within catheter 705A. FIG. 7B
shows a notch 722B that opens to a larger size within catheter
705B. FIG. 7C shows yet another embodiment of notch 722C formed
within catheter 705C in which one side of notch 722C may be
slightly curved and an opposite side may be substantially straight.
In one embodiment, the notches described herein may have a depth of
about 0.5 mm to 1.5 mm and a length of about 1 mm to 4 mm.
[0043] FIGS. 8A-8D illustrate cross sectional views of alternative
embodiments for a groove that may be formed within embodiments of a
medical device described herein (e.g., groove 232 described with
respect to FIG. 2 and cross sectional view FIG. 2C). In one
embodiment, the groove formed within a catheter provides support to
keep the cutting element upright and prevent tilting while the
cutting element moves within the catheter. The shape of the groove
may also serve to prevent the wire and/or cutting element from
popping out during movement. The groove also provides a track so
that the cutting element may maintain a linear path when pulled by
the wire disposed within the groove. In one embodiment, a
cross-sectional design of the wire may determine the corresponding
design of the groove. For example, FIG. 8A shows wire 830A having a
substantially spherical design and groove 832A having a
hemispherical design to accommodate the design of wire 830A.
Cutting element 840A is shown coupled to wire 830A. FIG. 8B shows
another embodiment of a groove design for a substantially spherical
wire 830B in which groove 832B has a substantially straight portion
that opens up to substantially spherical groove. A portion of
cutting element 840B may sit deeper in groove 832B compared to
cutting element 840A. FIG. 8C shows another embodiment of a groove
design in which wire 830C has a substantially elliptical shape with
groove 832C also having a substantially elliptical shape. FIG. 8D
shows yet another embodiment of a groove design in which wire 830D
may have a substantially trapezoidal shape with groove 832D having
a similar design to accommodate wire 830D. The embodiments for a
groove shown in FIGS. 8B-8D may be especially effective in
preventing a wire from popping of the groove during movement of the
cutting element. Moreover, because a portion of cutting element is
embedded within the grooves in these embodiments, rotation of the
cutting element may be effectively prevented.
[0044] FIGS. 9A-9B illustrate an alternative embodiment for
preventing rotation of a cutting element disposed within a
catheter. In this embodiment, a longitudinal length of the notch is
made shorter than the cutting element such that a portion of the
cutting element is always contained within the catheter.
Additionally, a width of the catheter may be just large enough to
contain the cutting element and prevent its rotation. FIG. 9A shows
a side view of catheter 900 having a cutting element 940
overlapping a size of notch 922. FIG. 9B shows a top view of
catheter 900 with cutting element 940 spanning across a
longitudinal length of notch 922. Because cutting element 940 is
longer than notch 922, the cutting element 940 tends not to rotate
when exposed in notch 922.
[0045] FIGS. 10A-10D illustrate one exemplary method for cutting a
mitral valve chordae tendineae percutaneously. In one embodiment,
the medical device used to cut the chordae may be device 200
described above with respect to FIG. 2. FIG. 10A illustrates a
simplified, cross-sectional view of a left side of a heart
including aortic arch 202, left atrium 204 and left ventricle 206.
A chordae tendineae 208 attaches a mitral valve leaflet 207 with a
tissue portion of left ventricle 206. For the purposes of
describing a method to cut a target chordae, only chordae 208 is
shown, although it may be understood that more than one chordae may
be cut with device 200. A distal portion of catheter 205 has been
percutaneously advanced into the left ventricle 206. In one
embodiment, a guidewire (not shown) may be initially advanced into
the left ventricle by inserting the guidewire into, for example,
the femoral artery, down the aortic arch 202, and into left
ventricle 206. Catheter 205 may be loaded and tracked over the
guidewire to be positioned near chordae 208 (e.g., through
guidewire lumen 250 formed within catheter 205). In alternative
embodiments, catheter 205 may be any of the catheter types used in
the art, including but not limited to "rapid exchange" (RX)
catheters, "over-the-wire" (OTW) catheters, or a "tip RX"
catheters. If a guidewire is utilized, the guidewire may be removed
after the distal portion of catheter 205 has entered the left
ventricle. Various imaging techniques known in the art may also be
used to locate chordae 208. For example, echo imaging, infrared
illumination, x-ray, and magnetic resonance imaging methods may be
utilized. These imaging techniques are known in the art;
accordingly, a detailed description is not provided.
[0046] Catheter 205 extends back to a proximal portion 210 disposed
outside of a patient. Catheter 205 may be coupled to a control
mechanism 212 which includes control handles 214, 215, 216. The
control handles may be used, in one embodiment, to steer and/or
rotate the distal portion of catheter 205, in particular, to
position notch 222 around chordae 208. For example, handles 214,
216 may be manipulated to steer and/or rotate catheter 205 (e.g.,
with steering tendons 270, 272 described above) to position chordae
208 within notch 222 as illustrated by FIG. 10B. With notch 222
positioned around chordae 208, handle 215 disposed on control
mechanism may be pulled (in the direction of the arrow as indicated
in FIG. 10C) to retract a cutting element (e.g., cutting element
240) disposed within catheter 205 from a position on a distal side
to a proximal side of notch 222. In one embodiment, the action of
the cutting element may be that described above with respect to
cutting element 340 of FIGS. 3A-3B. FIG. 10D shows chordae 208
having been cut into two portions. Catheter 205 may then be tracked
back up the aortic arch 202 and out of the patient or
alternatively, notch 222 may be positioned over another target
chordae to be severed. For example, handles 214, 216 may be used to
steer catheter 205 to another target chordae, and handle 215 used
to reposition the cutting element near a distal side of notch
222.
[0047] In one embodiment, a heart chord cutting method discussed
herein may be combined with another approach for treating a
defective mitral valve (e.g., mitral valve regurgitation). This
additional approach includes applying a support member in the
coronary sinus near the mitral valve region or applying a support
member on the mitral valve itself, such as on the mitral valve
annulus, or applying a first support member in the coronary sinus
and applying a second support member on the mitral valve annulus.
In this embodiment, a general technique would include cutting
percutaneously one or more heart chords and also applying
percutaneously a support member on the mitral valve or applying a
support member in the coronary sinus. The combination of
percutaneous chord cutting with this additional percutaneous
approach should provide improved mitral valve functionality. These
additional approaches are described in several co-pending U.S.
patent applications which are hereby incorporated by reference,
these applications being: (1) Apparatus and Methods for Heart Valve
Repair, by inventors Gregory M. Hyde, Mark Juravic, Stephanie A
Szobota, and Brad D. Bisson, filed Nov. 15, 2002, attorney docket
no. 005618.P3591; (2) Heart Valve Catheter, by inventor Gregory M.
Hyde, filed Nov. 15, 2002, attorney docket no. 005618.P3456; (3)
Valve Adaptation Assist Device, by inventors William E. Webler,
James D. Breeding, Brad D. Bisson, Firas Mourtada, Gregory M. Hyde,
Stephanie A. Szobota, Gabriel Asongwe, and Jeffrey T. Ellis, filed
Nov. 15, 2002, attorney docket no. 005618.P3665; (4) Valve Annulus
Constriction Apparatus and Method, by inventors Peter L. Callas and
Richard Saunders, filed Nov. 15, 2002, attorney docket no.
005618.P3560; (5) Methods for Heart Valve Repair, by inventors
William E. Webler, Gregory M. Hyde, Christopher Feezor and Daniel
L. Cox, filed Nov. 15, 2002, attorney docket no. 005618.P3635; and
(6) Apparatus and Methods for Heart Valve Repair, filed Oct. 15,
2002, attorney docket no. 005618.P3575.
[0048] A kit (e.g., a kit of multiple catheters with instructions)
maybe used to perform the combination of the percutaneous chord
cutting with another percutaneous approach (e.g., such as applying
percutaneously a mitral valve annulus). For example, a first
catheter, such as catheter 205 described above, may be combined
with a kit with a second catheter designed to apply a member
percutaneously, such as a support annulus to the mitral valve
region or a stent-like structure in the coronary sinus near the
mitral valve. The second catheter may be used to deploy a support
annulus around the mitral valve annulus to reshape the mitral
valve, or a set of joined clips which grasp mitral valve leaflets,
or a stent or ring or stent-like structure in the coronary sinus to
reshape the mitral valve.
[0049] For example, FIGS. 12A-12B illustrate one embodiment of
performing a combination procedure of percutaneous mitral valve
chordae cutting with percutaneous placement of a support annulus on
the mitral valve annulus. FIG. 12A shows a first catheter 205
having a cutting element disposed near a distal end and positioned
near chordae 208 in left ventricle 206. A second catheter 290 has
also been advanced percutaneously into the left atrium 204 (e.g.,
transeptally) and positioned over mitral valve annulus 295. A
support member 292 is disposed near a distal portion of second
catheter 290. FIG. 12B shows chordae 280 having been cut with a
cutting element (e.g., cutting element 240 described above), as
well as support member 290 having been attached to mitral valve
annulus 295. Upon completion of each percutaneous procedure, first
catheter 205 may be removed back up the aortic arch 202 and second
catheter 290 may be removed back across the septum.
[0050] In the foregoing specification, a medical device has been
described with reference to specific exemplary embodiments thereof.
For example, the medical device may be used to treat heart chords
other than the chordae tendineae of the mitral valve. It will,
however, be evident that various modifications and changes may be
made thereto without departing from the broader spirit and scope of
the medical device as set forth in the appended claims. The
specification and figures are, accordingly, to be regarded in an
illustrative rather than a restrictive sense.
* * * * *