U.S. patent application number 10/369271 was filed with the patent office on 2004-01-22 for sheath for use with an ultrasound element.
Invention is credited to Lichttenegger, Gary, Rodriguey, James E., Tachibana, Katsuro, Zhang, John.
Application Number | 20040015122 10/369271 |
Document ID | / |
Family ID | 22314719 |
Filed Date | 2004-01-22 |
United States Patent
Application |
20040015122 |
Kind Code |
A1 |
Zhang, John ; et
al. |
January 22, 2004 |
Sheath for use with an ultrasound element
Abstract
A system for delivering ultrasound energy to a treatment section
in a vessel is disclosed. The system includes a sheath with a
utility lumen and an energy delivery section at least partially
constructed from a material which transmits ultrasound energy. The
system also includes a drug delivery member having a plurality of
drug delivery ports which are positioned adjacent the energy
delivery section. The system further includes an elongated body
including at least one ultrasound element and configured to be
movably positioned within the utility lumen to transmit the
ultrasound energy from the ultrasound element through the energy
delivery section.
Inventors: |
Zhang, John; (Bothell,
WA) ; Lichttenegger, Gary; (Woodinville, WA) ;
Rodriguey, James E.; (Seattle, WA) ; Tachibana,
Katsuro; (Fukuoka-shi, JP) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
22314719 |
Appl. No.: |
10/369271 |
Filed: |
February 18, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10369271 |
Feb 18, 2003 |
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09107078 |
Jun 29, 1998 |
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Current U.S.
Class: |
604/22 |
Current CPC
Class: |
A61M 2025/0057 20130101;
A61B 2018/00011 20130101; A61B 2017/22084 20130101; A61B
2017/320073 20170801; A61B 17/22 20130101; A61M 37/0092 20130101;
A61B 1/00135 20130101; A61B 17/2202 20130101; A61B 2017/320084
20130101; A61B 2017/22082 20130101; A61M 5/14 20130101; A61M
2025/105 20130101; A61M 25/007 20130101; A61B 8/12 20130101 |
Class at
Publication: |
604/22 |
International
Class: |
A61B 017/20 |
Claims
What is claimed is:
1. A system for delivering ultrasound energy to a treatment section
in a vessel, comprising: a sheath having a utility lumen and an
energy delivery section at least partially constructed from a
material which transmits ultrasound energy; a drug delivery member
having a plurality of drug delivery ports which are positioned
adjacent the energy delivery section; and an elongated body
including at least one ultrasound element and configured to be
movably positioned within the utility lumen to transmit the
ultrasound energy from the ultrasound element through the energy
delivery section.
2. The system of claim 1, wherein the plurality of drug delivery
ports have geometries which cause a substantially equal flow of a
drug solution from each drug delivery port.
3. The system of claim 2, wherein the drug delivery ports increase
in size in a distal direction along the drug delivery member.
4. The system of claim 2, wherein the drug delivery ports are slit
shaped.
5. The system of claim 1, wherein the density of the drug delivery
port increases in a distal direction along the drug delivery
member.
6. The system of claim 1, wherein the drug delivery member is
integral with the sheath.
7. The system of claim 1, wherein the drug delivery member is
external to the sheath.
8. The system of claim 1, wherein the drug delivery member is wound
around the energy delivery section.
9. The system of claim 1, further comprising: at least one second
drug delivery member including drug delivery ports positioned
adjacent the energy delivery section.
10. The system of claim 1, wherein the sheath includes a support
section which provides the sheath with support and kink
resistance.
11. The system of claim 10 wherein the support section is
constructed from copolyester.
12. The system of claim 1, wherein the energy delivery section is
constructed from polyimide.
13. The system of claim 1, further comprising: an occluding device
positioned at a distal end of the sheath and having a geometry
preventing the ultrasound element from exiting a distal end of the
utility lumen.
14. The system of claim 13, wherein the utility lumen extends
through the occluding device and is configured to receive a
guidewire.
15. The system of claim 1, wherein the utility lumen is configured
to receive a guidewire.
16. The system of claim 1, further comprising: at least one second
ultrasound element included in the elongated body.
17. The system of claim 1, wherein positioning the elongated body
within the utility lumen forms a lumen between a side of the
utility lumen and a surface of the elongated body and the lumen is
configured to receive an ultrasound element cooling fluid.
18. The system of claim 1, further comprising: at least one
temperature sensor positioned at a sheath distal end.
19. The system of claim 18, further comprising: a feedback control
system for adjusting a power delivered to the ultrasound element in
response to a signal from the at least one temperature sensor.
20. The systme of claim 1, further comprising: a balloon positioned
at the energy delivery section.
21. The system of claim 1, wherein the balloon is constructed from
a membrane.
22. The system of claim 1, wherein the balloon is constructed from
a selectively permeable material.
23. A sheath for delivering ultrasound energy to a treatment
section in a vessel, comprising: a utility lumen configured to
movably receive an elongated body with an ultrasound element; an
energy delivery section at least partially constructed from a
material which transmits ultrasound energy from the ultrasound
element; and a plurality of drug delivery ports positioned adjacent
the energy delivery section.
24. The sheath of claim 23, wherein the plurality of drug delivery
ports have geometries which cause a substantially equal flow of a
drug solution from each drug delivery port.
25. The sheath of claim 23, wherein the drug delivery ports
increase in size in a distal direction along the drug delivery
member.
26. The sheath of claim 25, wherein the drug delivery ports are
slit shaped.
27. The sheath of claim 23, wherein the density of the drug
delivery port increases in a distal direction along the drug
delivery member.
28. The sheath of claim 23, further comprising: a drug delivery
member which includes the drug delivery ports.
29. The system of claim 28, wherein the drug delivery member is
external to the sheath.
30. The sheath of claim 29 wherein the drug delivery member is
wound around the energy delivery section.
31. The sheath of claim 23, wherein the sheath includes a support
section which provides the sheath with support and kink
resistance.
32. The sheath of claim 31 wherein the support section is
constructed from copolyester.
33. The sheath of claim 23, wherein the energy delivery section is
constructed from polyimide.
34. The sheath of claim 23, further comprising: an occluding device
positioned at a distal end of the sheath and having a geometry
configured to prevent the ultrasound element from exiting a distal
end of the utility lumen.
35. The sheath of claim 34, wherein the utility lumen extends
through the occluding device and is configured to receive a
guidewire.
36. The sheath of claim 23, wherein the utility lumen is configured
to receive a guidewire.
37. The sheath of claim 23, wherein positioning the elongated body
within the utility lumen forms a lumen between a side of the
utility lumen and a surface of the elongated body and the lumen is
configured to receive an ultrasound element cooling fluid.
38. The sheath of claim 23, further comprising: at least one
temperature sensor positioned at a sheath distal end.
39. The sheath of claim 38, further comprising: a feedback control
system for adjusting a power delivered to the ultrasound element in
response to a signal from the at least one temperature sensor.
40. A system for delivering ultrasound energy to a treatment
section in a vessel, comprising: a sheath having a utility lumen
configured to movably receive an elongated body with an ultrasound
element and an energy delivery section at least partially
constructed from a material which transmits ultrasound energy from
the ultrasound element; and a drug delivery member having a
plurality of drug delivery ports which are configured to be
positioned adjacent the energy delivery section.
41. The sheath of claim 40, wherein the plurality of drug delivery
ports have geometries which cause a substantially equal flow of a
drug solution from each drug delivery port.
42. The system of claim 40, wherein the density of the drug
delivery port increases in a distal direction along the drug
delivery member.
43. The system of claim 40 wherein the drug delivery member is
configured to be wound around the energy delivery section.
44. The system of claim 40, wherein the sheath includes a support
section which provides the sheath with support and kink
resistance.
45. The system of claim 44, wherein the support section is
constructed from copolyester.
46. The system of claim 40, wherein the energy delivery section is
constructed from polyimide.
47. The system of claim 40, wherein positioning the elongated body
within the utility lumen forms a lumen between a side of the
utility lumen and a surface of the elongated body and the lumen is
configured to receive an ultrasound element cooling fluid.
48. A sheath for delivering ultrasound energy to a treatment
section in a vessel, comprising: a sheath having a utility lumen
configured to movably receive an elongated body with an ultrasound
element and an energy delivery section at least partially
constructed from a material which transmits ultrasound energy from
the ultrasound element; and at least one temperature sensor
positioned adjacent the energy delivery section.
49. The sheath of claim 48, further comprising: a drug delivery
member having a plurality of drug delivery ports which are
configured to be positioned adjacent the energy delivery
section.
50. The sheath of claim 49, wherein the plurality of drug delivery
ports have geometries which cause a substantially equal flow of a
drug solution from each drug delivery port.
51. The sheath of claim 48, further comprising: a feedback control
system for adjusting a power delivered to the ultrasound element in
response to a signal from the at least one temperature sensor.
52. A system for delivering ultrasound energy to a treatment
section in a vessel, comprising: a sheath having a utility lumen
and an energy delivery section at least partially constructed from
a material which transmits ultrasound energy; an expandable balloon
positioned at least partially adjacent the energy delivery section;
and an elongated body including at least one ultrasound element and
configured to be movably positioned within the utility lumen to
transmit the ultrasound energy from the ultrasound element through
the energy delivery section.
53. The system of claim 52, wherein: the balloon is constructed
from a membrane.
54. The systme of claim 52, wherein: the balloon is constructed
from a selectively permeable membrane.
55. The system of claim 52, further comprising: a plurality of drug
delivery ports included on the sheath within the balloon.
56. The system of claim 55, wherein the drug delivery ports have
geometries to provide a substantially equal flow of a drug solution
from each drug delivery port.
57. The system of claim 52, wherein the sheath includes a support
section which provides the sheath with support and kink
resistance.
58. The system of claim 52, further comprising: an occluding device
positioned at a distal end of the sheath and having a geometry
preventing the ultrasound element from exiting a distal end of the
utility lumen.
59. A system for delivering ultrasound energy to a treatment
section in a vessel, comprising: a sheath having a utility lumen
and an energy delivery section at least partially constructed from
a material which transmits ultrasound energy; and an elongated body
configured to be movably received within the utility lumen and
including a cooling fluid lumen passing sufficiently close to
ultrasound element positioned at a distal end of the elongated body
that the ultrasound element can be cooled by a cooling fluid flowed
through the cooling fluid lumen.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an ultrasound enhanced drug
delivery apparatus, and more particularly, to an ultrasound element
which can be movably positioned within a drug delivery sheath.
[0003] 2. Description of Related Art
[0004] Thrombus formation is a protective and healing mechanism,
however, formation of thrombi can be detrimental. For instance, if
a blood vessel becomes blocked, distal tissue may be deprived of
oxygen with resulting damage or necrosis. In the case of cerebral
circulation, an arterial thrombus blockage is one cause of cerebral
strokes. In the case of coronary thrombosis, blockage and
subsequent distal tissue necrosis of cardiac muscle tissue will
impair cardiac pump output, may cause electrical abnormalities, and
potentially catastrophic heart failure and death. The thrombus can
form at the site of artery narrowing due to arterial wall damage or
disease, or the thrombus may have broken free from some proximal
site only to become wedged in a distal stenosis. Thrombus can also
form subsequent to attempts to remove a stenosis using balloon
angioplasty or rotary atherectomy.
[0005] Ultrasound sheaths have been described specifically for
removal or dissolution of thrombus (U.S. patents: Tachibana U.S.
Pat. No. 5,197,946; Bernstein U.S. Pat. No. 5,163,421; Weng U.S.
Pat. No. 5,269,297). The sheaths of Bernstein and Weng place an
ultrasound generator external to the body and transmit acoustic
energy through a metal wire wave-guide to the distal sheath. The
sheath of Tachibana includes a small ultrasound element positioned
at the distal end of the sheath that is energized by electrical
wires. In either case, ultrasound energy is delivered to and
radiated from the distal tip of the sheath in the vicinity of a
blocking thrombus. The application of ultrasound can directly
emulsify nearby thrombus through the motion of the sheath tip,
associated cavitation, and bioeffects.
[0006] The application of ultrasound can also enhance delivery of
drug into a vessel wall. There are instances where the vessel wall
is diseased or has been injured during balloon angioplasty or
rotary atherectomy. Narrowing of the vessel can occur in response
to these injuries. Certain drugs, such as heparin, may inhibit this
narrowing of the blood vessel if the drug can be delivered into the
blood vessel wall. A sheath can be used to deliver drugs into any
portion of the body or target organ. Ultrasound energy in the
presence of these drugs can enhance the delivery through and across
bodily fluids and tissue. Hence, an ultrasound drug delivery sheath
placed in a blood vessel will assist delivery across the blood
vessel wall, whether it be an artery or a vein, into the
surrounding muscle or tissue.
[0007] The intensity of the ultrasound delivered from a cylindrical
ultrasound element decreases exponentially with radial distance
from the sheath tip. Hence, treatment of thrombi is limited to the
circumferential area surrounding of the sheath tip of a sheath with
an ultrasound element. This limited treatment area may be effective
for small length clots, however, larger clots must be treated one
section at a time.
[0008] Some thrombi can be large. For instance, a deep vein
thrombus in a patient's lower leg and can have a length from
several centimeters to as much as 30-50 cm long. Early treatment
protocols for these long thrombi used a drug infusion sheath to
drip lytic drug at one end of a thrombus. As the thrombus was
dissolved, the sheath would be advanced. This process was repeated
until the entire clot was dissolved. More current therapy for a
deep vein thrombosis is to use an infusion sheath with drug
infusion ports distributed along the lateral dimension of the
sheath. The sheath can be pushed through the entire length of the
clot. The thrombolytic drug is then infused throughout the lesion
for a period of hours.
[0009] There is a need for an ultrasound sheath that is useful for
treating a deep vein thrombus to enhance and accelerate the action
of the thrombolytic drug. There is a further need for an ultrasound
sheath that is useful for treating vessel lesions, particularly
those that have extensive lengths.
SUMMARY OF THE INVENTION
[0010] A system for delivering ultrasound energy to a treatment
section in a vessel is disclosed. The system includes a sheath with
a utility lumen and an energy delivery section at least partially
constructed from a material which transmits ultrasound energy. The
system also includes a drug delivery member having a plurality of
drug delivery ports which are positioned adjacent the energy
delivery section. The system further includes an elongated body
including at least one ultrasound element and configured to be
movably positioned within the utility lumen to transmit the
ultrasound energy from the ultrasound element through the energy
delivery section.
[0011] In another embodiment the system includes a sheath having a
utility lumen configured to movably receive an elongated body with
an ultrasound element and an energy delivery section at least
partially constructed from a material which transmits ultrasound
energy from the ultrasound element. The system also includes a drug
delivery member having a plurality of drug delivery ports which are
configured to be positioned adjacent the energy delivery
section.
[0012] A sheath for delivering ultrasound energy to a treatment
section in a vessel is also disclosed. The sheath includes a
utility lumen configured to movably receive an elongated body with
an ultrasound element. The sheath also includes an energy delivery
section at least partially constructed from a material which
transmits ultrasound energy from the ultrasound element. A
plurality of drug delivery ports are positioned adjacent the energy
delivery section.
[0013] In another embodiment, the sheath includes a utility lumen
configured to movably receive an elongated body with an ultrasound
element. The sheath also includes an energy delivery section at
least partially constructed from a material which transmits
ultrasound energy from the ultrasound element. At least one
temperature sensor is positioned adjacent the energy delivery
section.
[0014] A system for delivering ultrasound energy to a treatment
section in a vessel is disclosed. The system includes a sheath
having a utility lumen and an energy delivery section which is at
least partially constructed from a material which transmits
ultrasound energy. An expandable balloon positioned at least
partially adjacent the energy delivery section. The system also
includes an elongated body with at least one ultrasound element.
The elongated body is configured to be movably positioned within
the utility lumen to transmit the ultrasound energy from the
ultrasound element through the energy delivery section.
BRIEF DESCRIPTION OF THE FIGURES
[0015] FIG. 1A is a sideview of a sheath and elongated body
according to the present invention.
[0016] FIG. 1B is a sideview of a sheath and elongated body
according to the present invention.
[0017] FIG. 2A is a cross section of a sheath with an elongated
body positioned within a utility lumen.
[0018] FIG. 2B is a cross section of a sheath proximal end.
[0019] FIG. 2C is a cross section of an elongated body including a
body lumen.
[0020] FIG. 2D is a cross section of an elongated body including a
body lumen positioned within a sheath including a closed occlusion
device.
[0021] FIG. 2E is a cross section of an elongated body including a
body lumen positioned within a sheath including a closed occlusion
device.
[0022] FIG. 3A is a sideview of a sheath distal end.
[0023] FIG. 3B is a cross sectional view of a sheath distal
end.
[0024] FIG. 3C is a sideview of a sheath distal end.
[0025] FIG. 3D is a cross sectional view of a sheath distal
end.
[0026] FIG. 3E illustrates a drug delivery member with slit shaped
drug delivery ports.
[0027] FIG. 3F illustrates a drug delivery member with arc shaped
slits as drug delivery ports.
[0028] FIG. 4A is a sideview of a sheath distal end with drug
delivery ports of increasing size.
[0029] FIG. 4B is a is a cross sectional view of a sheath distal
end.
[0030] FIG. 5 is a cross section of a sheath distal end with an
integral occlusion device.
[0031] FIG. 6A is a sideview of a sheath including a balloon.
[0032] FIG. 6B is a cross section a balloon positioned at a distal
end of a sheath which includes drug delivery ports configured to
produce an even flow along the length of the energy delivery
section.
[0033] FIG. 6C is a cross section of a balloon positioned at a
distal end of a sheath which includes an expansion lumen for
expanding the balloon and delivering a drug solution.
[0034] FIG. 6D is a cross section of a balloon positioned at a
distal end of a sheath which includes an expansion lumen for
expanding the balloon and drug delivery ports configured to produce
an even flow along the length of the energy delivery section.
[0035] FIG. 7A illustrates ultrasound elements connected in
parallel.
[0036] FIG. 7B illustrates ultrasound elements connected in
series.
[0037] FIG. 7C illustrates ultrasound elements connected with a
common wire.
[0038] FIG. 8 illustrates temperature sensors connected with a
common wire.
[0039] FIG. 9 is a block diagram of a feedback control system.
[0040] FIG. 10A is a cross section of a treatment site.
[0041] FIG. 10B is a sideview of a sheath distal end positioned at
a treatment site.
[0042] FIG. 10C is a sideview of a sheath distal end positioned at
a treatment site.
[0043] FIG. 10D is a sideview of a sheath proximal end.
[0044] FIG. 10E is a cross section of a sheath distal end
positioned at a treatment site.
[0045] FIG. 10F illustrates an ultrasound element positioned within
a utility lumen.
[0046] FIG. 10G is a sideview of a sheath distal end positioned at
a treatment site.
[0047] FIG. 11A illustrates a balloon positioned adjacent a
clot.
[0048] FIG. 11B illustrates a balloon expanded into contact with
the clot of FIG. 11A.
DETAILED DESCRIPTION
[0049] The invention relates to a system for delivering ultrasound
energy to a treatment section in a vessel. The system includes a
sheath with an energy delivery section at least partially
constructed from a material which transmits ultrasound energy. The
sheath is designed to be positioned within a vessel such that at
least a portion of the energy delivery section is positioned
adjacent a treatment site within the vessel. The system also
includes an elongated body with an ultrasound element positioned at
its distal end. The elongated body can be received in a utility
lumen included in the sheath such that the ultrasound element is
positioned within the energy delivery section. Ultrasound energy
can be delivered from the ultrasound element through the energy
delivery section to the treatment site.
[0050] The elongated body can be moved within the utility lumen so
the ultrasound element can be moved relative to the energy delivery
section. As a result, the ultrasound element can be moved within
the treatment site to deliver ultrasound energy to different
sections of the treatment site. The motion of the ultrasound
element relative to the treatment site can help emulsify a clot,
thrombus or other blockage at the treatment site. Since, the
ultrasound element is being moved relative to the treatment site
within the sheath, the movement of the ultrasound element relative
to the treatment site does not damage the vessel including the
treatment site.
[0051] The elongated body can include a cooling fluid lumen which
passes adjacent the ultrasound element. Similarly, a cooling fluid
lumen can be formed between the elongated body and the sheath. A
cooling fluid can be passed through the cooling fluid lumen to cool
the ultrasound element. The heating of the ultrasound element can
limit the amount of power which can be provided to the ultrasound
element. Cooling the ultrasound element during its operation allows
the power provided to the ultrasound element to be increased. As a
result, cooling the ultrasound element can increase the efficiency
of the treatment. Movement of the ultrasound element can be
accomplished manually or through use of an automated method.
[0052] The system can also include a drug delivery member which
includes a plurality of drug delivery ports which are positioned
adjacent to the energy delivery section. The drug delivery ports
permit delivery of a drug solution to the treatment site.
Ultrasound energy can also be delivered to the treatment site to
enhance the effect of the drug within the treatment site.
[0053] The drug delivery member can be external to the energy
delivery section. As a result, a drug solution does not need to be
delivered through the energy delivery section allowing the energy
delivery section to be constructed of acoustically transparent
materials which cannot be easily extruded. The energy delivery
section can also be very thin since a drug delivery lumen need not
pass through materials comprising the energy delivery section.
Thinner materials increase the acoustic transparency of the energy
delivery section. Suitable materials for the energy delivery
section include, but are not limited to, polyimides. The portion of
the sheath which is not included in the energy delivery section can
be constructed from materials such as polyurethanes, copolyesters,
or thermoplastic elastomers which provides the sheath with kink
resistance, rigidity and structural support necessary to transport
the energy delivery section to the treatment site.
[0054] The sheath can also include at least one temperature sensor
positioned adjacent the energy delivery section. The temperature
sensors can be coupled with a feedback control system. The feedback
control system can be used to adjust the level of power delivered
to the ultrasound element in response to the signal from at least
one temperature sensor. As a result, the temperature at the
treatment site can be maintained within a desired range during the
treatment.
[0055] FIG. 1A illustrates a drug delivery system 10 according to
the present invention. The system 10 includes a sheath 12 with a
sheath proximal end 14 and a sheath distal end 16. The sheath
distal end 16 includes, a support section 17, an energy delivery
section 18, temperature sensors 20 and an occlusion device 22. The
sheath proximal end 14 includes temperature sensor leads 24 and a
cooling fluid fitting 26. A utility lumen 28 extends through the
sheath 12 along the length of the sheath 12. A drug delivery member
30 is positioned adjacent the energy delivery section. The drug
delivery member 30 includes a drug inlet port 32 which can be
coupled with a drug source via a connector such as a Luer type
fitting. The drug delivery member 30 can be incorporated into the
support section 17 as illustrated in FIG. 1A or can external to the
support section as illustrated in FIG. 1B. The system 10 also
includes an elongated body 34 with a body proximal end 36 and a
body distal end 38. An ultrasound element 40 is positioned at the
body distal end 38.
[0056] The elongated body 34 has an outer diameter which permits
the elongated body 34 to be inserted into the utility lumen 28.
FIG. 2A illustrates the elongated body 34 threaded through the
utility lumen 28 until the ultrasound element 40 is positioned
within the energy delivery section 18. Suitable outer diameters of
the elongated body 34 include, but are not limited to,
0.010"-0.100". Suitable diameters of the utility lumen 28 include,
but are not limited to 0.015"-0.110". The utility lumen 28 extends
through the occlusion device 22. The portion of the utility lumen
28 extending through the occlusion device 22 has a diameter which
can accommodate a guidewire (not shown) but which prevents the
ultrasound element 40 from passing through the occlusion device 22.
Suitable inner diameters for the occlusion device 22 include, but
are not limited to 0.005"-0.050".
[0057] The ultrasound element 40 can be rotated or moved within the
energy delivery section 18 as illustrated by the arrows 52
illustrated in FIG. 2A. The movement of the ultrasound element 40
within the energy delivery section 18 can be caused by manipulating
the body proximal section while holding the sheath proximal section
stationary. The elongated body 34 can be at least partially
constructed from a material which provides enough structural
support to permit movement of the elongated body 34 within the
sheath 12 without kinking of the elongated body 34. Suitable
materials for the elongated body 34 include, but are not limited to
polyesters, polyurethanes, thermoplastic, elastomers.
[0058] As illustrated in FIG. 2A, the outer diameter of the
elongated body 34 can be smaller than the diameter of the utility
lumen 28 to create a cooling fluid lumen 44 between the elongated
body 34 and the utility lumen 28. A cooling fluid can be flowed
through the cooling fluid lumen 44, past the ultrasound element 40
and through the occlusion device 22. The flowrate of the cooling
fluid and/or the power to the ultrasound element 40 can be adjusted
to maintain the temperature of the ultrasound element 40 within a
desired range.
[0059] The sheath proximal end 14 can include a cap 46 as
illustrated in FIG. 2B. A cooling fluid can be flowed from the
cooling fluid fitting 26 through the cooling fluid lumen 44 as
illustrated by the arrows 48. The cap 46 includes a hemostasis
valve 50 with an inner diameter which substantially matches the
diameter of the elongated body 34. The matched diameters reduces
leaking of the cooling fluid between the cap 46 and the elongated
body 34.
[0060] As illustrated in FIG. 2C, the ultrasound element 40 can be
a hollow cylinder and the elongated body can include a body lumen
51 which extends through the ultrasound element 40. The cooling
fluid can be flowed through the body lumen past the ultrasound
element 40 to provide cooling to the ultrasound element 40.
[0061] As illustrated in FIG. 2D, the occlusion device 22 can be
integral with the sheath 12 and can have a closed end. The body
lumen 51 can serve as a return lumen for the cooling fluid. As a
result, the inside and the outside of the ultrasound element 40 are
exposed to the cooling fluid to accelerate the cooling of the
ultrasound element 40. As illustrated in FIG. 2D, the flow of the
cooling fluid can be reversed so the cooling lumen serves as the
return cooling fluid lumen. The above cooling schemes permit the
power provided to the ultrasound element to be increased in
proportion to the cooling flow rate. Further, certain schemes can
prevent exposure of the body to cooling fluids.
[0062] The drug delivery member 30 includes a drug delivery portion
which is positioned adjacent the energy delivery section 18 as
illustrated in FIG. 3A. As illustrated in FIG. 3B, the drug
delivery member 30 includes a drug delivery lumen 56 extending
through the length of the drug delivery member 30. The drug
delivery member 30 also includes a series of drug delivery ports 58
coupled with the drug delivery lumen 56. A drug source coupled with
the drug inlet port 32 can provide a pressure which drives a drug
solution through the drug delivery lumen 56 and out the drug
delivery ports 58. A suitable material for the drug delivery member
30 includes, but is not limited to, polyimide, polyolefin,
polyester.
[0063] The sheath 12 can include a plurality of drug delivery
members 30. The drug delivery members 30 can be wound around the
energy delivery section 18 or they can be positioned along the
length of the energy delivery section 18 as illustrated in FIG. 3C.
Each drug delivery member 30 can be coupled with the same drug
inlet port 32. In another embodiment, each drug delivery member 30
is coupled with independent drug inlet ports 32 so different drug
solutions can be delivered to different drug delivery ports 58.
[0064] The drug delivery ports 58 are positioned close enough to
achieve a substantially even flow of drug solution around the
circumference of the energy delivery section 18 and along the
length of the energy delivery sections 18. The proximity of
adjacent drug delivery ports 58 can be changed by changing the
density of drug delivery ports 58 along the drug delivery member,
by changing the number of windings of the drug delivery member
around the energy delivery section 18 or by changing the number of
drug delivery members 30 included adjacent the energy delivery
section 18. A suitable displacements between adjacent drug delivery
ports 58 include, but are not limited to, from 0.1" to 1.0",
preferable 0.2" to 0.6".
[0065] The size of the drug delivery ports 58 can be the same or
change along the length of the drug delivery member. For instance,
the size of the drug delivery ports 58 distally positioned on the
drug delivery section can be larger than the size of the drug
delivery ports 58 which are proximally positioned on the drug
delivery section. The increase in sizes of the drug delivery ports
58 can be designed to produce similar flowrates of drug solution
through each drug delivery port 58. This similar flowrate increases
the uniformity of drug solution flowrate along the length of the
sheath 12. When the drug delivery ports 58 have similar sizes along
the length of the drug delivery member, a suitable size for a drug
delivery port 58 includes, but is not limited to 0.0005" to
0.0050". When the size of the drug delivery ports 58 changes along
the length of the drug delivery member, suitable sizes for
proximally positioned drug delivery ports 58 includes, but is not
limited to from 0.0001" to 0.005" and suitable sizes for distally
positioned drug delivery ports 58 includes, but is not limited to
0.0005" to 0.0020". The increase in size between adjacent drug
delivery ports can be substantially uniform between or along the
drug delivery member. The dimensional increase of the drug delivery
ports is dependent upon material and diameter of the drug delivery
member. The drug delivery ports 58 can be burnt into the drug
delivery member 30 with a laser.
[0066] Uniformity of the drug solution flow along the length of the
sheath 12 can also be increased by increasing the density of the
drug delivery ports 58 toward the distal end of the drug delivery
member.
[0067] The drug delivery ports 58 can be slits with a straight
shape as illustrated in FIG. 3E or an arcuate shape as illustrated
in FIG. 3F. The drug delivery member 30 can be constructed from
materials such as polyimide, nylon, pebax, polyurethane or silicon.
When the dug delivery lumen 56 is filled with drug solution, the
slits remain closed until the pressure within the drug delivery
lumen exceeds a threshold pressure. As the pressure within the drug
delivery lumen builds, the pressure on each of the slits will be
approximately uniform. Once, the threshold pressure is reached, the
uniform pressure will result in the slits opening almost
simultaneously and cause a nearly uniform flow of drug solution out
of all the slits. When the pressure within the drug delivery lumen
56 falls below the threshold pressure, the slits close and prevent
delivery of additional drug solution. The stiffer the material used
to construct the drug deliver member, the higher the threshold
pressure required to open the slit shaped drug delivery ports. The
slit shape can also prevent the drug delivery ports 58 from opening
when exposed to low pressures from outside the sheath 12. As a
result, slit shaped drug delivery ports can maximize control of
drug delivery.
[0068] The sheath 12 and energy delivery section 18 can be
constructed from a single material as illustrated in FIG. 4A.
Suitable materials include, but are not limited to polyimide,
polyolefin, polyester. The entire sheath or only the sheath
proximal end may be reinforced by braiding, mesh or other
constructions to increase flexibility, kink resistance, and
pushability. As illustrated in FIG. 4A, the drug delivery ports 58
can be included in the sheath 12. The drug delivery ports 58 can be
coupled with independent drug delivery lumens 28 as illustrated in
FIG. 4B.
[0069] The sheath can include a support section 17 which is
constructed from a different material than the energy delivery
section as illustrated in FIG. 5. FIG. 5 also illustrates the
occlusion device 22 as being integral with the energy delivery
section 18. The energy delivery section 18 can be constructed from
a material which readily transmits ultrasound energy. The support
section can be constructed from a material which provides
structural strength and kink resistance. Further, the support
section or the proximal end of the support section may be
reinforced by braiding, mesh or other constructions to increase
flexibility, kink resistance, and pushability. Suitable materials
for the support section include, but are not limited to,
polyimides, polyolefin, polyester. A suitable outer diameter for
the support section includes, but is not limited to 0.020" to
0.200". Suitable materials for the energy delivery section 18
include, but are not limited to, polyolefins, polyimides, polyester
and other low ultrasound impedance materials. Low ultrasound
impedance materials are materials which readily transmit ultrasound
energy with minimal absorption of the ultrasound energy.
[0070] The sheath distal end 16 can include a balloon 59 as
illustrated in FIG. 6A. The balloon 59 can be constructed from
permeable membrane or a selectively permeable membrane which allows
certain media to flow through the membrane while preventing other
media from flowing through the membrane. Suitable materials for the
balloon 59 include, but are not limited to cellulose, cellulose
acetate, polyvinylchloride, polyolefin, polyurethane and
polysulfone. When the balloon is constructed from a permeable
membrane or a selectively permeable membrane, the membrane pore
sizes are preferably 5 A-2 .mu.m, more preferably 50 A-900 A and
most preferably 100 A-300 A in diameter.
[0071] As illustrated in FIGS. 6B, the balloon 59 can be positioned
adjacent drug delivery ports 58. The drug delivery ports 58 can be
designed so a uniform flow occurs along the length of the energy
delivery section 18. This design can serve to prevent a pressure
gradient from developing along the length of the balloon.
Delivering a drug solution through the drug delivery ports 58 can
serve to expand the balloon 59. When the balloon 59 is constructed
from a membrane or a selectively permeable membrane, the drug
solution can be delivered with enough pressure to drive the drug
across the membrane. Various phoretic processes and apparatuses can
also be used to drive the drug solution across the membrane. When
the balloon 59 is constructed from a selectively permeable
membrane, the pressure and/or phoresis may drive only certain
components of the drug solution across the membrane while
preventing other components from crossing the membrane.
[0072] The balloon 59 can also be positioned adjacent one or more
expansion ports 60A coupled with an expansion lumen 60B as
illustrated in FIG. 6C. The drug solution can be delivered to the
balloon 59 via the expansion-lumen 60B. Delivering a drug solution
through the expansion lumen 60B can serve to expand the balloon 59.
When the balloon 59 is constructed from a membrane or a selectively
permeable membrane, the drug can be delivered with enough pressure
to drive the drug solution or certain components of the drug
solution across the membrane. Similarly, phoretic means can also be
used to drive the drug solution or certain components of the drug
solution across the membrane.
[0073] The balloon 59 can also be positioned adjacent expansion
ports 60A coupled with an expansion lumen 60B and drug delivery
ports 58 as illustrated in FIG. 6D. Different drug solutions can be
delivered through the expansion ports 60B and the drug delivery
ports 58. Further, a media suitable for expanding the balloon 59
can be delivered through the expansion lumen 60B and the expansion
ports 60A while the drug solution can be delivered through the drug
delivery ports 58. When the balloon 59 is constructed from a
membrane or a selectively permeable membrane, a medium which wets
the membrane and enhances the permeability of the membrane can be
delivered through the expansion ports 60A. A drug solution can be
delivered through the drug delivery ports 58 concurrently with or
after the wetting medium has been delivered.
[0074] The ultrasound energy can be generated at an ultrasound
energy source which is remote from the ultrasound elements 40 and
transmitted via wire to the ultrasound elements 40. Ultrasound can
also be internally generated from electrical power delivered to the
ultrasound elements 40 from an electrical energy source. A suitable
example of an ultrasound element 40 for internal generation of
ultrasound energy includes, but is not limited to, piezoelectric
ceramic oscillators. The ultrasound elements 40 can be shaped as a
cylinder, a hollow cylinder and a disk which are concentric with
the elongated body 34. The ultrasound elements 40 can also be an
array of smaller ultrasound elements 40 or a thin plate positioned
within the elongated body 34. Similarly, a single ultrasound
element 40 can be composed of several smaller ultrasound elements
40. Suitable frequencies for the ultrasound element include, but
are not limited to from 20 KHz to 2 MHz.
[0075] Each ultrasound element 40 can each be individually powered.
When the elongated body 34 includes N ultrasound elements 40, the
elongated body 34 must include 2N wires to individually power N
ultrasound elements 40. The individual ultrasound elements 40 can
also be electrically coupled in serial or in parallel as
illustrated in FIGS. 7A and 7B. These arrangements permit maximum
flexibility as they require only 2N wires. Each of the ultrasound
elements 40 receive power simultaneously whether the ultrasound
elements 40 are in series or in parallel. When the ultrasound
elements 40 are in series, less current is required to produce the
same power from each ultrasound element 40 than when the ultrasound
elements 40 are connected in parallel. The reduced current allows
smaller wires to be used to provide power to the ultrasound
elements 40 and accordingly increases the flexibility of the
elongated body 34. When the ultrasound elements 40 are connected in
parallel, an ultrasound element 40 can break down and the remaining
ultrasound elements 40 will continue to operate.
[0076] As illustrated in FIG. 7C, a common wire 61 can provide
power to each of ultrasound element 40 while each ultrasound
element 40 has its own return wire 62. A particular ultrasound
element 40 can be individually activated by closing a switch 64 to
complete a circuit between the common wire 61 and the particular
ultrasound element's return wire 62. Once a switch 64 corresponding
to a particular ultrasound element 40 has been closed, the amount
of power supplied to the ultrasound element 40 can be adjusted with
the corresponding potentiometer 66. Accordingly, an elongated body
34 with N ultrasound elements 40 requires only N+1 wires and still
permits independent control of the ultrasound elements 40. This
reduced number of wires increases the flexibility of the elongated
body 34. To improve the flexibility of the elongated body 34, the
individual return wires 62 can have diameters which are smaller
than the common wire 61 diameter. For instance, in an embodiment
where N ultrasound elements 40 will be powered simultaneously, the
diameter of the individual return wires 62 can be the square root
of N times smaller than the diameter of the common wire 61.
[0077] As illustrated in FIG. 1, the system 10 can include at least
one temperature sensor 20. Suitable temperature sensors 20 include,
but are not limited to, thermistors, thermocouples, resistance
temperature detectors (RTD)s, and fiber optic temperature sensors
which use thermalchromic liquid crystals. Suitable temperature
sensor 20 geometries include, but are not limited to, a point,
patch, stripe and a band around the sheath 12. The temperature
sensors 20 can be positioned on the sheath 12 or on the elongated
body 34 near the ultrasound elements 40. The temperature sensors 20
should be positioned so they are exposed to the portion of a
treatment section which is receiving drug solution and/or
ultrasound energy.
[0078] The temperature sensors 20 can be electrically connected as
illustrated in FIG. 8. Each temperature sensor 20 can be coupled
with a common wire 61 and then include its own return wire 62.
Accordingly, N+1 wires can be used to independently sense the
temperature at the temperature sensors 20 when N temperature
sensors 20 are employed. A suitable common wire 61 can be
constructed from Constantan and suitable return wires 62 can be
constructed from copper. The temperature at a particular
temperature sensor 20 can be determined by closing a switch 64 to
complete a circuit between the thermocouple's return wire 62 and
the common wire 61. When the temperature sensors 20 are
thermocouples, the temperature can be calculated from the voltage
in the circuit. To improve the flexibility of the sheath 12, the
individual return wires 62 can have diameters which are smaller
than the common wire 61 diameter.
[0079] Each temperature sensor 20 can also be independently wired.
Employing N independently wired temperature sensors 20 requires 2N
wires to pass the length of the sheath 12.
[0080] The sheath 12 or elongated body 34 flexibility can also be
improved by using fiber optic based temperature sensors 20. The
flexibility can be improved because only N fiber optics need to be
employed sense the temperature at N temperature sensors 20.
[0081] The system 10 can be include a feedback control system 68 as
illustrated in FIG. 9. The temperature at each temperature sensor
20 is monitored and the output power of energy source adjusted
accordingly. The physician can, if desired, override the closed or
open loop system.
[0082] The feedback control system 68 includes an energy source 70,
power circuits 72 and a power calculation device 74 coupled with
the ultrasound elements 40. A temperature measurement device 76 is
coupled with the temperature sensors 20 on the sheath 12. A
processing unit 78 is coupled with the power calculation device 74,
the power circuits 72 and a user interface and display 80.
[0083] In operation, the temperature at each temperature sensor 20
is determined at the temperature measurement device 76. The
processing unit 78 receives each determined temperature from the
temperature measurement device 76. The determined temperature can
then be displayed to the user at the user interface and display
80.
[0084] The processing unit 78 includes logic for generating a
temperature control signal. The temperature control signal is
proportional to the difference between the measured temperature and
a desired temperature. The desired temperature can be determined by
the user. The user can set the predetermined temperature at the
user interface and display 80.
[0085] The temperature control signal is received by the power
circuits 72. The power circuits 72 adjust the power level of the
energy supplied to the ultrasound elements 40 from the energy
source 70. For instance, when the temperature control signal is
above a particular level, the power supplied to a particular
ultrasound element 40 is reduced in proportion to the magnitude of
the temperature control signal. Similarly, when the temperature
control signal is below a particular level, the power supplied to a
particular ultrasound element 40 is increased in proportion to the
magnitude of the temperature control signal. After each power
adjustment, the processing unit 78 monitors the temperature sensors
20 and produces another temperature control signal which is
received by the power circuits 72.
[0086] The processing unit 78 can also include safety control
logic. The safety control logic detects when the temperature at a
temperature sensor 20 has exceeded a safety threshold. The
processing unit 78 can then provide a temperature control signal
which causes the power circuits 72 to stop the delivery of energy
from the energy source 70 to the ultrasound elements 40.
[0087] Since, the ultrasound elements 40 may be mobile relative to
the temperature sensors 20, it can be unclear which ultrasound
transducer should have a power level adjustment. As a result, the
power level may be identically adjusted at each ultrasound element
40. Further, the power supplied to each of the ultrasound elements
40 may be adjusted in response to the temperature sensor 20 which
indicates the highest temperature. Making power adjustments in
response to the temperature of the temperature sensor 20 indicating
the highest temperature can prevent overheating of the treatment
site.
[0088] The processing unit 78 also receives a power signal from a
power calculation device 74. The power signal can be used to
determine the power being received by each ultrasound element 40.
The determined power can then be displayed to the user on the user
interface and display 80.
[0089] The feedback control system 68 can maintain the tissue
adjacent to the ultrasound elements 40 at a desired temperature for
a selected period of time. As described above, the ultrasound
elements 40 can be electrically connected so each ultrasound
element 40 can generate an independent output. The output maintains
a selected energy at each ultrasound element 40 for a selected
length of time.
[0090] The processing unit 78 can be a digital or analog
controller, or a computer with software. When the processing unit
78 is a computer it can include a CPU coupled through a system bus.
The user interface and display 80 can be a mouse, keyboard, a disk
drive, or other non-volatile memory systems, a display monitor, and
other peripherals, as are known in the art. Also coupled to the bus
is a program memory and a data memory.
[0091] In lieu of the series of power adjustments described above,
a profile of the power delivered to each ultrasound element 40 can
be incorporated in the processing unit 78 and a preset amount of
energy to be delivered may also be profiled. The power delivered to
each ultrasound element 40 can the be adjusted according to the
profiles.
[0092] FIGS. 10A-10G illustrate a method for using the system 10.
In FIG. 10A, a guidewire 84 similar to a to a guidewire used in
typical angioplasty procedures is directed through vessels 86
toward a treatment site 88 which includes a clot 90. The guidewire
84 is directed through the clot 90. Suitable vessels include, but
are not limited to, cardiovascular vessels, the pancreas, sinuses,
esophagus, rectum, gastrointestinal vessels and urological
vessels.
[0093] In FIG. 10B, the utility lumen 28 of the sheath 12 is slid
over the guidewire 84 and the sheath 12 is advanced along the
guidewire 84 using traditional over-the-guidewire techniques. The
sheath 12 is advanced until the energy delivery section 18 of the
sheath 12 is positioned at the clot 90. Radio opaque markers may be
positioned at the energy delivery section 18 of the sheath 12 to
aid in the positioning of the sheath 12 within the treatment site
88.
[0094] In FIG. 10C, the guidewire 84 is withdrawn from the utility
lumen 28 by pulling the guidewire 84 proximally while holding the
sheath 12 stationary. In FIG. 10D, a temperature monitor 92 is
coupled with the temperature sensor leads 24, a cooling fluid
source 94 is coupled with the cooling fluid inlet and a drug
solution source 96 is coupled with the drug inlet port 32. The drug
solution source 96 can be a syringe with a Luer fitting which is
complementary with the drug inlet port 32. Pressure can be applied
to a plunger 98 on the drug solution source 96 to drive the drug
solution through the drug delivery lumen 56. The drug solution is
delivered from the drug delivery lumen 56 through the drug delivery
ports 58 as illustrated by the arrows 100 in FIG. 10E. Suitable
drug solutions include, but are not limited to, an aqueous solution
containing Heparin, Uronkinase, Streptokinase, or tissue
Plasminogen Activator (TPA).
[0095] In FIG. 10F, the elongated body 34 is inserted into the
utility lumen 28 until the ultrasound element 40 is positioned
within the energy delivery section 18. To aid in placement of the
ultrasound element 40 within the energy delivery section 18,
radiopaque markers may be positioned on the elongated body 34
adjacent to each of the ultrasound elements 40. The ultrasound
elements 40 themselves can be radiopaque. Once the elongated body
34 is properly positioned, the ultrasound element 40 is activated
to deliver ultrasound energy through the energy delivery section 18
to the clot 90. Suitable ultrasound energy is delivered with a
frequency from 20 KHz to 2 MHz. While the ultrasound energy s being
delivered, the ultrasound element 40 can be moved within the energy
delivery section 18 as illustrated by the arrows 52. The movement
of the ultrasound element 40 within the energy delivery section 18
can be caused by manipulating the body proximal section while
holding the sheath proximal section stationary. A cooling fluid is
flowed through the cooling fluid lumen 44 and out the occlusion
device 22.
[0096] The cooling fluid can be delivered before, after, during or
intermittently with the delivery of the ultrasound energy.
Similarly, the drug solution can be delivered before, after, during
or intermittently to the delivery of ultrasound energy. As a
result, the acts illustrated in FIGS. 10A-10F can be performed in
different orders than are described above. The drug solution and
energy are applied until the clot 90 is partially or entirely
dissolved as illustrated in FIG. 10G. Once the clot 90 has been
dissolved to the desired degree, the sheath 12 and elongated body
34 are withdrawn from the treatment site 88.
[0097] FIGS. 11A-11B illustrate a method for using the system 10
when the sheath distal end 16 includes a balloon 59. The sheath 12
is, advanced through a vessel 86, as described above, until the
balloon 59 is positioned adjacent a clot 90 as illustrated in FIG.
11A. The balloon 59 is expanded until the balloon 59 contacts the
clot 90 as illustrated in FIG. 11B. As described above, the balloon
59 can be expanded by delivering a drug solution through an
expansion port 60A or a drug delivery port 58 or by delivering an
expansion media through an expansion port 60A. Once the balloon 59
contacts the clot 90, the drug solution or components of the drug
solution are driven across the membrane so the drug solution or the
components of the drug solution contact the clot 90. The elongated
body 34 can be inserted into the sheath 12 before, after or
concurrently with the expansion of the balloon 59 and/or the
delivery of the drug solution. Similarly, the ultrasound element 40
can be operated before, after, intermittently or concurrently with
the expansion of the balloon 59 and/or the delivery of the drug
solution.
[0098] The foregoing description of a preferred embodiment of the
invention has been presented for purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise forms disclosed. Obviously, many
modifications, combinations and variations will be apparent to
practitioners skilled in this art.
* * * * *