U.S. patent application number 10/799278 was filed with the patent office on 2004-09-02 for apparatus and method for an ultrasonic probe used with a pharmacological agent.
This patent application is currently assigned to OmniSonics Medical Technologies, Inc.. Invention is credited to Buffen, Elaine S., Gosnell, Mark R., Hare, Bradley A., Marciante, Rebecca I., Rabiner, Robert A., Senseney-Mellor, Heather L..
Application Number | 20040171981 10/799278 |
Document ID | / |
Family ID | 28046909 |
Filed Date | 2004-09-02 |
United States Patent
Application |
20040171981 |
Kind Code |
A1 |
Rabiner, Robert A. ; et
al. |
September 2, 2004 |
Apparatus and method for an ultrasonic probe used with a
pharmacological agent
Abstract
The present invention provides an apparatus and a method of
using an ultrasonic probe with a pharmacological agent to enhance
an occlusion treating effect of the ultrasonic probe to effectively
remove an occlusion. The pharmacological agent is released through
a catheter to treat the occlusion and enhance an effect of a
transverse ultrasonic vibration of the ultrasonic probe to
effectively remove the occlusion. The pharmacological agent
continues to travel downstream of the site of the occlusion and
work in conjunction with the ultrasonic probe to reduce the
occlusion to a size that can easily be removed from the body
naturally in order to prevent reformation of the occlusion and
other health risks.
Inventors: |
Rabiner, Robert A.; (North
Reading, MA) ; Hare, Bradley A.; (Chelmsford, MA)
; Marciante, Rebecca I.; (North Reading, MA) ;
Buffen, Elaine S.; (Westborough, MA) ; Gosnell, Mark
R.; (Weston, MA) ; Senseney-Mellor, Heather L.;
(Durham, NH) |
Correspondence
Address: |
PALMER & DODGE, LLP
RICHARD B. SMITH
111 HUNTINGTON AVENUE
BOSTON
MA
02199
US
|
Assignee: |
OmniSonics Medical Technologies,
Inc.
|
Family ID: |
28046909 |
Appl. No.: |
10/799278 |
Filed: |
March 12, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10799278 |
Mar 12, 2004 |
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10396914 |
Mar 25, 2003 |
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6733451 |
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10396914 |
Mar 25, 2003 |
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10373134 |
Feb 24, 2003 |
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10373134 |
Feb 24, 2003 |
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09784619 |
Feb 15, 2001 |
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6524251 |
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09784619 |
Feb 15, 2001 |
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09618352 |
Jul 19, 2000 |
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6551337 |
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60178901 |
Jan 28, 2000 |
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60157824 |
Oct 5, 1999 |
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Current U.S.
Class: |
604/20 ;
600/439 |
Current CPC
Class: |
A61B 2017/00274
20130101; A61B 2017/22002 20130101; A61B 2018/00547 20130101; A61B
2017/22015 20130101; A61B 2017/00137 20130101; A61B 2017/320084
20130101; A61N 7/022 20130101; A61B 17/22012 20130101; A61B
2017/22018 20130101; A61B 2017/320069 20170801; A61B 2017/22007
20130101; A61B 2017/22008 20130101; A61B 2017/320089 20170801 |
Class at
Publication: |
604/020 ;
600/439 |
International
Class: |
A61N 001/30 |
Claims
What is claimed is:
1. An ultrasonic medical device comprising: a catheter having a
proximal end, a distal end and a plurality of fenestrations along a
longitudinal axis of the catheter; and an ultrasonic probe inserted
into the catheter, the ultrasonic probe having a proximal end, a
distal end and a longitudinal axis therebetween, wherein the
catheter delivers a pharmacological agent to dissolve an occlusion
and the ultrasonic probe vibrates in a transverse mode to ablate
the occlusion along a portion of the longitudinal axis of the
ultrasonic probe and a probe tip.
2. The ultrasonic medical device of claim 1 wherein the plurality
of fenestrations are spaced circumferentially along the
catheter.
3. The ultrasonic medical device of claim 1 wherein the plurality
of fenestrations are located at the distal end of the catheter.
4. The ultrasonic medical device of claim 1 wherein the occlusion
comprises a biological material.
5. The ultrasonic medical device of claim 1 wherein the
pharmacological agent softens the occlusion.
6. The ultrasonic medical device of claim 1 wherein the
pharmacological agent moves in a radial direction through the
plurality of fenestrations.
7. The ultrasonic medical device of claim 1 wherein the
pharmacological agent is a tissue plasminogen activator.
8. The ultrasonic medical device of claim 1 wherein the
pharmacological agent is selected from a group consisting of
thrombolytic agents, antiplatelet drugs, lysing agents,
anticoagulants and similar agents that treat the occlusion.
9. The ultrasonic medical device of claim 1 wherein the
pharmacological agent is selected from a group consisting of
aspirin, dipyridamole, glycoprotein inhibitors, thienopyrindines,
clopidogrel, hirudin, urokinase, streptokinase, heparin, warfarin
and similar agents that treat the occlusion.
10. The ultrasonic medical device of claim 1 wherein a transverse
ultrasonic vibration of the ultrasonic probe produces a plurality
of transverse nodes and a plurality of transverse anti-nodes along
a portion of the longitudinal axis of the ultrasonic probe.
11. The ultrasonic medical device of claim 1 wherein the ultrasonic
probe ablates the occlusion adjacent to a plurality of transverse
anti-nodes along the portion of the longitudinal axis of the
ultrasonic probe.
12. The ultrasonic medical device of claim 1 wherein the ultrasonic
probe is disposable.
13. The ultrasonic medical device of claim 1 wherein the ultrasonic
probe is for a single use on a single patient.
14. An ultrasonic medical device for destroying a biological
material comprising: a catheter having a proximal end, a distal end
and a plurality of fenestrations along a longitudinal axis of the
catheter; an ultrasonic probe inserted into the catheter; and a
pharmacological agent delivered through the catheter to enhance a
biological material destroying effect of the ultrasonic probe
vibrating in a transverse mode along a portion of a longitudinal
axis of the ultrasonic probe and a probe tip.
15. The ultrasonic medical device of claim 14 wherein the
pharmacological agent moves through an open area between the
ultrasonic probe and the catheter.
16. The ultrasonic medical device of claim 14 wherein the
pharmacological agent moves in a radial direction through the
plurality of fenestrations along the catheter.
17. The ultrasonic medical device of claim 14 wherein the plurality
of fenestrations are spaced circumferentially along the
catheter.
18. The ultrasonic medical device of claim 14 wherein the
pharmacological agent is a tissue plasminogen activator.
19. The ultrasonic medical device of claim 14 wherein the
pharmacological agent is selected from a group consisting of
thrombolytic agents, antiplatelet drugs, lysing agents,
anticoagulants and similar agents that treat the biological
material.
20. The ultrasonic medical device of claim 14 wherein the
pharmacological agent is selected from a group consisting of
aspirin, dipyridamole, glycoprotein inhibitors, thienopyrindines,
clopidogrel, hirudin, urokinase, streptokinase, heparin, warfarin
and similar agents that treat the biological material.
21. The ultrasonic medical device of claim 14 wherein a transverse
ultrasonic vibration of the ultrasonic probe produces a plurality
of transverse nodes and a plurality of transverse anti-nodes along
a portion of the longitudinal axis of the ultrasonic probe.
22. The ultrasonic medical device of claim 14 wherein the
ultrasonic probe destroys the biological material adjacent to a
plurality of transverse anti-nodes along the portion of the
longitudinal axis of the ultrasonic probe.
23. The ultrasonic medical device of claim 14 wherein more than one
of the plurality of transverse anti-nodes are in communication with
the biological material.
24. The ultrasonic medical device of claim 14 wherein the
pharmacological agent dissolves the biological material.
25. A method of ablating a biological material comprising:
delivering a catheter into a vasculature; inserting an ultrasonic
probe into the catheter, the ultrasonic probe having a proximal
end, a distal end and a longitudinal axis therebetween; releasing a
pharmacological agent through the catheter, the pharmacological
agent moving through a plurality of fenestrations located along the
catheter to dissolve the biological material; extending a section
of the longitudinal axis of the ultrasonic probe beyond a distal
end of the catheter; and activating an ultrasonic energy source
coupled to the ultrasonic probe to generate an ultrasonic energy
that produces a transverse ultrasonic vibration of the ultrasonic
probe; and ablating the biological material adjacent to the section
of the longitudinal axis of the ultrasonic probe and a probe
tip.
26. The method of claim 25 wherein the pharmacological agent and
the ultrasonic probe work in combination to ablate the biological
material.
27. The method of claim 25 further comprising pushing the section
of the longitudinal axis of the ultrasonic probe beyond the distal
end of the catheter.
28. The method of claim 25 further comprising pulling back the
catheter to extend the section of the longitudinal axis of the
ultrasonic probe beyond the distal end of the catheter.
29. The method of claim 25 further comprising engaging the
pharmacological agent to the biological material and moving the
pharmacological agent downstream from the biological material.
30. The method of claim 25 wherein the pharmacological agent is
localized at the biological material.
31. The method of claim 25 further comprising breaking up the
biological material into a particulate with a combination of the
ultrasonic energy from the ultrasonic probe and the pharmacological
agent.
32. The method of claim 31 further comprising breaking up the
particulate into an aggregate with a combination of the ultrasonic
energy and the pharmacological agent.
33. The method of claim 25 further comprising producing a plurality
of transverse nodes and a plurality of transverse anti-nodes along
the section of the longitudinal axis of the ultrasonic probe.
34. The method of claim 25 further comprising ablating the
biological material adjacent to a plurality of transverse
anti-nodes along the section of the longitudinal axis of the
ultrasonic probe.
35. The method of claim 25 wherein the pharmacological agent is a
tissue plasminogen activator.
36. The method of claim 25 wherein the pharmacological agent is
selected from a group consisting of thrombolytic agents,
antiplatelet drugs, lysing agents, anticoagulants and similar
agents that treat the occlusion.
37. The method of claim 25 wherein the pharmacological agent is
selected from a group consisting of aspirin, dipyridamole,
glycoprotein inhibitors, thienopyrindines, clopidogrel, hirudin,
urokinase, streptokinase, heparin, warfarin and similar agents that
treat the occlusion.
38. A method of destroying a biological material comprising:
delivering a catheter into a vasculature; inserting an ultrasonic
probe into the catheter, the ultrasonic probe having a proximal
end, a distal end and a longitudinal axis therebetween; releasing a
pharmacological agent through a plurality of fenestrations along
the catheter to dissolve the biological material; exposing a
section of the longitudinal axis of the ultrasonic probe; and
activating an ultrasonic energy source coupled to the ultrasonic
probe to generate an ultrasonic energy; and vibrating in a
transverse mode at least the section of the longitudinal axis of
the ultrasonic probe and a probe tip to destroy the biological
material.
39. The method of claim 38 further comprising pushing the section
of the longitudinal axis of the ultrasonic probe beyond a distal
end of the catheter.
40. The method of claim 38 further comprising pulling back on the
catheter to expose the section of the longitudinal axis of the
ultrasonic probe beyond a distal end of the catheter.
41. The method of claim 38 further comprising producing a plurality
of transverse nodes and a plurality of transverse anti-nodes along
the section of the longitudinal axis of the ultrasonic probe.
42. The method of claim 38 further comprising ablating the
biological material adjacent to a plurality of transverse
anti-nodes along the section of the longitudinal axis of the
ultrasonic probe.
43. The method of claim 38 further comprising breaking up the
particulate into an aggregate with a combination of the ultrasonic
energy and the pharmacological agent.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of 10/396,914, filed Mar.
25, 2003 which is a continuation-in-part of application Ser. No.
10/373,134, filed Feb. 24, 2003, which is a continuation of
application Ser. No. 09/784,619, filed Feb. 15, 2001, now U.S. Pat.
No. 6,524,251, which is a continuation-in-part of application Ser.
No. 09/618,352, filed on Jul. 19, 2000, now U.S. Pat. No.
6,551,337, which claims the benefit of Provisional Application
Serial No. 60/178,901, filed Jan. 28, 2000, and claims the benefit
of Provisional Application Serial No. 60/157,824, filed Oct. 5,
1999, the entirety of all these applications are hereby
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to an ultrasonic medical
device, and more particularly to an apparatus and method of using
an ultrasonic probe with a pharmacological agent to treat an
occlusion and effectively remove the occlusion and prevent
subsequent occlusion formation and other health risks.
BACKGROUND OF THE INVENTION
[0003] Vascular occlusive disease affects millions of individuals
worldwide and is characterized by a dangerous blockage of
vasculatures. Vascular occlusive disease includes thrombosed
hemodialysis grafts, peripheral artery disease, deep vein
thrombosis, coronary artery disease, heart attack and stroke.
Vasculatures include veins, arteries, blood vessels, intestines,
ducts and other body lumens that materials may flow through. Heart
attacks are an especially common vascular occlusive disease, with
an approximate annual rate of 800,000 people in the United States
having acute heart attacks with approximately 213,000 of those
people dying. Strokes are also common, with approximately 80% of
all strokes being ischemic strokes caused when a vascular occlusion
formed in one part of the body travels to a smaller blood vessel in
the brain and inhibits blood flow to the brain. Vascular occlusions
(clots, intravascular blood clots or thrombus, occlusional
deposits, such as calcium deposits, fatty deposits, atherosclerotic
plaque, cholesterol buildup, fibrous material buildup, arterial
stenoses) result in the restriction or blockage of blood flow in
the vasculatures in which they occur. Occlusions result in oxygen
deprivation ("ischemia") of tissues supplied by these blood
vessels. Prolonged ischemia results in permanent damage of tissues
which can lead to myocardial infarction, stroke or death.
Occlusions frequently occur in coronary arteries, peripheral
arteries and other blood vessels.
[0004] The disruption of an occlusion can be affected by mechanical
methods, ultrasonic methods, pharmacological agents or combinations
of all three. Many procedures involve inserting an insertion lumen
into a vasculature of a body. Insertion lumens include, but are not
limited to, probes, catheters, wires, tubes and similar
devices.
[0005] Mechanical methods of treating thrombolysis include balloon
angioplasty, which can result in ruptures in a blood vessel, and is
generally limited to larger blood vessels. In addition, scarring of
vessels is common, which may lead to the formation of a secondary
occlusion (a process known as restenosis). Another common problem
is secondary vasoconstriction (classic recoil), a process by which
spasms or an abrupt closure of the blood vessel occurs. These
problems are common in treatments employing interventional devices.
In traditional angioplasty, for instance, a balloon catheter is
inserted into the occlusion, and through the application of
hydraulic forces in the range of about ten to about fourteen
atmospheres of pressure, the balloon is inflated. The
non-compressible balloon applies this significant force to compress
and flatten the occlusion, thereby opening the vessel for blood
flow. However, these extreme forces result in the application of
extreme stresses to the vessel, potentially rupturing the vessel,
or weakening it and thereby increasing the chance of post-operative
aneurysm, or creating vasoconstrictive or restenotic conditions. In
addition, the particulate matter forming the occlusion is not
removed, rather it is just compressed. Other mechanical devices
that drill through and attempt to remove an occlusion have also
been used, and create the same danger of physical damage to blood
vessels.
[0006] Ultrasonic probes using ultrasonic energy to fragment body
tissue have been used in many surgical procedures (see, e.g., U.S.
Pat. No. 5,112,300; U.S. Pat. No. 5,180,363; U.S. Pat. No.
4,989,583; U.S. Pat. No. 4,931,047; U.S. Pat. No. 4,922,902; and
U.S. Pat. No. 3,805,787). Ultrasonic devices used for vascular
treatments typically comprise an extracorporeal transducer coupled
to a solid metal wire which is then threaded through the blood
vessel and placed in contact with an occlusion (see, e.g., U.S.
Pat. No. 5,269,297). In some cases, the transducer, comprising a
bendable plate, is delivered to the site of the clot (see, e.g.,
U.S. Pat. No. 5,931,805).
[0007] Some ultrasonic devices include a mechanism for irrigating
an area where the ultrasonic treatment is being performed (e.g., a
body cavity or lumen) in order to wash biological material from the
area of treatment. Mechanisms used for irrigation or aspiration
known in the art are generally structured such that they increase
the overall cross-sectional profile of the elongated probe, by
including inner and outer concentric lumens within an ultrasonic
probe to provide irrigation and aspiration channels. In addition to
making the probe more invasive, prior art probes also maintain a
strict orientation of the aspiration and the irrigation mechanism,
such that the inner and outer lumens for irrigation and aspiration
remain in a fixed position relative to one another, which is
generally closely adjacent to the area of treatment. Thus, the
irrigation lumen does not extend beyond the suction lumen (i.e.,
there is no movement of the lumens relative to one another) and any
aspiration is limited to picking up fluid and/or tissue remnants
within the defined area between the two lumens.
[0008] As discussed above, medical devices utilizing ultrasonic
energy to destroy material comprising an occlusion in the human
body are known in the art. A major drawback of prior art ultrasonic
devices comprising a probe for occlusion removal is that the
devices are relatively slow in comparison to procedures that
involve surgical excision. This is mainly attributed to the fact
that such ultrasonic devices rely on imparting ultrasonic energy to
contacting occlusions by undergoing a longitudinal vibration of the
probe tip, wherein the probe tip is mechanically vibrated at an
ultrasonic frequency in a direction parallel to the probe
longitudinal axis. Thus, the treatment area is localized at the
probe tip, which substantially limits its ability to ablate large
occlusion areas in a short time. An ultrasonic medical device with
a multiple material coaxial construction for conducting axial
vibrations is known in the art (see, e.g., U.S. Pat. No.
6,277,084). In addition to prior art ultrasonic devices being slow,
previous ultrasonic methods of treating plaque still include many
undesirable complications and dangers to the patient.
[0009] The use of a pharmacological agent alone to treat a vascular
occlusion is common, but suffers from a variety of limitations that
compromise the effectiveness of the removal of the vascular
occlusion. It is difficult to disperse the pharmacological agent
symmetrically to the vascular occlusion, thereby leaving portions
of the vascular occlusion untreated. Often, portions of the
vascular occlusion are carried downstream of the site of the
vascular occlusion and lead to further problems including embolism.
In addition, delivery of the pharmacological agent is inefficient
and infusion times are long as the agent naturally dissolves into
areas of the vascular occlusion. Adverse complications such as
hemorrhages and bleeding are also common, thereby creating
additional health risks beyond those presented by the vascular
occlusion. Finally, large quantities of the pharmacological agent
are needed to treat the thrombus, thereby driving up the cost of
the treatment.
[0010] Prior art attempts to safely and effectively ablate an
occlusion in a vasculature of a body have been less than
successful. U.S. Pat. No. 6,508,782 to Evans et al. discloses a
catheter for dissolving blockages in tissues. The Evans et al.
device uses a catheter with an inflatable member either alone or in
conjunction with a medicament for dissolving the blockages. The
Evans et al. device discloses a catheter with an inflatable member
near the distal tip of the catheter to prevent the blockage from
passing downstream of the blockage and a perfusion channel for
removal of the broken up blockage. The Evans et al. device is
complicated, unreliable and necessitates a time consuming procedure
that requires the exchange of various lumens to deliver the
medicament and to vibrate the Evans et al. device. Since vibratory
motion for the Evans et al. device is longitudinal and at a distal
tip, the Evans et al. device does not focus on all parts of the
blockage and does not effectively and efficiently remove the
blockage. Therefore, there remains a need in the art for
effectively ablating an occlusion that combines the ultrasonic
energy of an ultrasonic probe with the dissolving effects of a
pharmacological agent that is simple, quick, reliable, efficient,
effective, does not harm healthy tissue and continues to break up
particulate of the occlusion downstream to prevent occlusion
formation downstream.
[0011] U.S. Pat. No. 5,925,016 to Chornenky et al. discloses a
system and a method for treating thrombosis by moving drugs through
the thrombus by pressure. The Chornenky et al. device isolates the
thrombus by using a catheter with an occlusion balloon proximal to
the thrombus, a guide wire with an occlusion placed distal to the
thrombus, and an infusion catheter that delivers drugs distal to
the thrombus through pressure. Since the Chornenky et al. device
relies on the drug and the non-symmetric pressurized delivery of
the drug to remove the thrombus, the thrombus is not effectively
removed and may result in complications downstream of the thrombus.
The Chornenky et al. device uses a time consuming procedure that
imparts high stresses to the vessel walls that can damage the
vessel. Therefore, there remains a need in the art for effectively
ablating an occlusion that combines the ultrasonic energy of an
ultrasonic probe with the dissolving effects of a pharmacological
agent that is simple, quick, reliable, efficient, effective, does
not harm healthy tissue and continues to break up particulate of
the occlusion downstream to prevent occlusion formation
downstream.
[0012] U.S. Pat. No. 6,280,413 to Clark et al. discloses a
thrombolytic filtration and drug delivery catheter comprising a
shaft and longitudinal ribs that are compressed when moved to the
treatment site and expand to a diameter greater than the shaft of
the catheter. In the Clark et al. device, drugs are delivered
through a lumen in the catheter and are delivered through ports in
the ribs. Since the Clark et al. device relies on the non-symmetric
dispersion of the drug, the Clark et al. device does not
effectively remove an occlusion and the occlusion can reform
downstream. The Clark et al. device is complicated and relies on a
separate lumen to remove the particles of the thrombus. In
addition, the longitudinal ribs of the Clark et. al. device can
impart high stresses to the vasculature and harm healthy tissue.
Therefore, there remains a need in the art for effectively ablating
an occlusion that combines the ultrasonic energy of an ultrasonic
probe with the dissolving effects of a pharmacological agent that
is simple, quick, reliable, efficient, effective, does not harm
healthy tissue and continues to break up particulate of the
occlusion downstream to prevent occlusion formation downstream.
[0013] The prior art attempts of removing an occlusion from a
vasculature in a body are complicated, expensive, unsafe,
ineffective, time consuming, inefficient and compromise the health
of a patient by potentially allowing the occlusion to reform
downstream. Therefore, there remains a need in the art for
effectively ablating an occlusion that combines the ultrasonic
energy of an ultrasonic probe with the dissolving effects of a
pharmacological agent that is simple, quick, reliable, efficient,
effective, does not harm healthy tissue and continues to break up
particulate of the occlusion downstream to prevent occlusion
formation downstream.
SUMMARY OF THE INVENTION
[0014] The present invention relates to an ultrasonic medical
device, and more particularly to an apparatus and method of using
an ultrasonic probe with a pharmacological agent to treat an
occlusion and effectively remove the occlusion and prevent
subsequent occlusion formation and other health risks.
[0015] The present invention is an ultrasonic medical device
comprising an ultrasonic probe and a catheter surrounding a length
of a longitudinal axis of the ultrasonic probe used with a
pharmacological agent. In a preferred embodiment of the present
invention, the catheter delivers the pharmacological agent to treat
the occlusion. In a preferred embodiment of the present invention,
the pharmacological agent is tissue plasminogen activator (tPA).
The pharmacological agent enhances an occlusion treatment effect of
the ultrasonic probe.
[0016] The present invention is an ultrasonic medical device
comprising an elongated, flexible probe and a catheter surrounding
a length of a longitudinal axis of the elongated, flexible probe. A
pharmacological agent moves through the catheter and enhances an
effect of a transverse ultrasonic vibration of the elongated,
flexible probe to treat the occlusion. The transverse ultrasonic
vibration of the elongated, flexible probe produces a plurality of
transverse nodes and transverse anti-nodes along a portion of the
longitudinal axis of the elongated, flexible probe.
[0017] The present invention provides a method of treating an
occlusion through the combined effects of an ultrasonic probe and a
pharmacological agent. The ultrasonic probe is inserted into a
vasculature, a catheter is delivered over a length of a
longitudinal axis of the ultrasonic probe and a pharmacological
agent is released through the catheter. A section of the
longitudinal axis of the ultrasonic probe is exposed to the
occlusion and an ultrasonic energy source is activated. The
pharmacological agent continues to move downstream of a site of the
occlusion to work in conjunction with the ultrasonic probe to
reduce the occlusion to a size that can easily be removed from the
body in conventional ways or simply dissolve into the blood
stream.
[0018] The present invention provides a method of removing an
occlusion by moving an elongated, flexible probe through a
vasculature to a site of an occlusion, releasing a pharmacological
agent in the vasculature and activating an ultrasonic energy source
to vibrate a longitudinal axis of the ultrasonic probe. The
pharmacological agent enhances an occlusion destroying effect of
the elongated, flexible probe.
[0019] The present invention is an ultrasonic medical device and a
pharmacological agent used together to treat an occlusion and
efficiently remove the occlusion to prevent subsequent reformation
of the occlusion and other health risks. The present invention
provides an apparatus and a method for more completely removing an
occlusion that is safe, simple, efficient, effective,
user-friendly, reliable and cost effective.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The present invention will be further explained with
reference to the attached drawings, wherein like structures are
referred to by like numerals throughout the several views. The
drawings shown are not necessarily to scale, with emphasis instead
generally being placed upon illustrating the principles of the
present invention.
[0021] FIG. 1 shows a longitudinal cross section of a vasculature
showing an ultrasonic medical device of the present invention
capable of operating in a transverse mode inserted into the
vasculature to treat an occlusion.
[0022] FIG. 2 shows a side plan view of an ultrasonic medical
device of the present invention capable of operating in a
transverse mode.
[0023] FIG. 3 shows a side plan view of an ultrasonic medical
device of the present invention capable of operating in a
transverse mode with a catheter surrounding a length of a
longitudinal axis of an ultrasonic probe.
[0024] FIG. 4 shows a side plan view of an alternative embodiment
of an ultrasonic medical device of the present invention showing a
plurality of transverse nodes and a plurality of transverse
anti-nodes along a portion of a longitudinal axis of the ultrasonic
probe.
[0025] FIG. 5 shows a fragmentary side plan view of a distal end of
an ultrasonic probe within a catheter.
[0026] FIG. 6 shows a fragmentary side plan view of a distal end of
an ultrasonic probe within a catheter wherein a section of a
longitudinal axis of the ultrasonic probe extends beyond a distal
end of the catheter.
[0027] While the above-identified drawings set forth preferred
embodiments of the present invention, other embodiments of the
present invention are also contemplated, as noted in the
discussion. This disclosure presents illustrative embodiments of
the present invention by way of representation and not limitation.
Numerous other modifications and embodiments can be devised by
those skilled in the art which fall within the scope and spirit of
the principles of the present invention.
DETAILED DESCRIPTION
[0028] The present invention provides an apparatus and a method of
using an ultrasonic probe with a pharmacological agent to enhance
an occlusion treating effect of the ultrasonic probe to effectively
remove an occlusion. The pharmacological agent treats the occlusion
at the site of the occlusion and continues to travel downstream to
further break up a particulate from the occlusion into an aggregate
with a size smaller than the particulate. In a preferred embodiment
of the present invention, the pharmacological agent is tissue
plasminogen activator (tPA).
[0029] The following terms and definitions are used herein:
[0030] "Ablate" as used herein refers to removing, clearing,
destroying or taking away a biological material. "Ablation" as used
herein refers to a removal, clearance, destruction, or taking away
of the biological material.
[0031] "Node" as used herein refers to a region of a minimum energy
emitted by an ultrasonic probe at or proximal to a specific
location along a longitudinal axis of the ultrasonic probe.
[0032] "Anti-node" as used herein refers to a region of a maximum
energy emitted by an ultrasonic probe at or proximal to a specific
location along a longitudinal axis of the ultrasonic probe.
[0033] "Probe" as used herein refers to a device capable of
propagating an energy emitted by the ultrasonic energy source along
a longitudinal axis of the ultrasonic probe, resolving the energy
into an effective cavitational energy at a specific resonance
(defined by a plurality of nodes and a plurality of anti-nodes
along an "active area" of the probe) and is capable of an acoustic
impedance transformation of ultrasound energy to a mechanical
energy.
[0034] "Transverse" as used herein refers to a vibration of a probe
not parallel a longitudinal axis of the probe. A "transverse wave"
as used herein is a wave propagated along the probe in which a
direction of a disturbance at a plurality of points of a medium is
not parallel to a wave vector.
[0035] "Biological material" as used herein refers to a collection
of a matter including, but not limited to, a group of similar
cells, intravascular blood clots or thrombus, fibrin, calcified
plaque, calcium deposits, occlusional deposits, atherosclerotic
plaque, fatty deposits, adipose tissues, atherosclerotic
cholesterol buildup, fibrous material buildup, arterial stenoses,
minerals, high water content tissues, platelets, cellular debris,
wastes and other occlusive materials.
[0036] "Occlusion" as used herein refers to a blockage, a clot, a
buildup or a deposit of a matter that results in an obstruction,
restriction, obstruction, constriction, blockage or closure at a
site of the occlusion.
[0037] "Particulate" as used herein refers to a smaller portion
separated from a larger occlusion and distinct from the
occlusion.
[0038] "Aggregate" as used herein refers to a smaller portion
separated from a particulate that is distinct from the
particulate.
[0039] FIG. 1 illustrates a section of an ultrasonic medical device
11 of the present invention proximal to an occlusion 16 inside a
vasculature 44. The ultrasonic medical device 11 includes an
ultrasonic probe 15 with a probe tip 9 at a distal end 24 of the
ultrasonic probe 15. A catheter 36 (shown in a retracted position)
surrounds a length of a longitudinal axis of the ultrasonic probe
15 and comprises a plurality of fenestrations 13 spaced
circumferentially along a length of the catheter 36. In a preferred
embodiment of the present invention, the plurality of fenestrations
13 are located at a distal end 34 of the catheter 36. A
pharmacological agent moves through an open area 19 between the
ultrasonic probe 15 and the catheter 36.
[0040] In a preferred embodiment of the present invention, the
pharmacological agent moves through the plurality of fenestrations
13 at the distal end 34 of the catheter 36. The catheter 36 with
the plurality of fenestrations 13 allows for the pharmacological
agent to uniformly engage the occlusion 16 as the pharmacological
agent moves in a radial direction through the plurality of
fenestrations 13. In another embodiment of the present invention,
the pharmacological agent moves through an opening 35 at a distal
end 34 of the catheter 36. In another embodiment of the present
invention, the pharmacological agent moves through one fenestration
13 at a position along the longitudinal axis of the catheter 36.
Those skilled in the art will recognize a pharmacological agent can
be moved through a catheter to engage an occlusion in many ways
known in the art and be within the spirit and scope of the present
invention.
[0041] FIG. 2 shows the ultrasonic medical device 11 of the present
invention. The ultrasonic medical device 11 includes the ultrasonic
probe 15 which is coupled to an ultrasonic energy source or
generator 99 (shown in phantom in FIGS. 2-4) for the production of
an ultrasonic energy. A handle 88, comprising a proximal end 87 and
a distal end 86, surrounds a transducer within the handle 88. The
transducer having a first end engaging the ultrasonic energy source
99 and a second end engaging a proximal end 31 of the ultrasonic
probe 15 transmits an ultrasonic energy to the ultrasonic probe 15.
A connector 93 engages the ultrasonic energy source 99 to the
transducer within the handle 88. The ultrasonic probe 15 includes
the proximal end 31 and the distal end 24 that ends in the probe
tip 9. A diameter of the ultrasonic probe 15 decreases from a first
defined interval 26 to a second defined interval 28 along the
longitudinal axis of the ultrasonic probe 15 over an at least one
diameter transition 82. A quick attachment-detachment system 33
that engages the proximal end 31 of the ultrasonic probe 15 to the
transducer within the handle 88 is illustrated generally in FIG. 2.
An ultrasonic probe device with a rapid attachment and detachment
means is described in the Assignee's co-pending patent applications
U.S. Ser. No. 09/975,725, now U.S. Pat. No. 6,695,782; U.S. Ser.
No. 10/268,487; U.S. Ser. No. 10/268,843, which further describe
the quick attachment-detachment (QAD) system and the entirety of
these applications are hereby incorporated herein by reference.
[0042] FIG. 3 shows the ultrasonic medical device 11 with a
catheter 36 surrounding a length of the longitudinal axis of the
ultrasonic probe 15. The catheter 36 comprises a proximal end 37, a
distal end 34 and the plurality of fenestrations 13 along a
longitudinal axis of the catheter 36. In the embodiment of the
present invention shown in FIG. 3, the catheter 36 includes a port
84, a one or more placement wings 95 and a one or more valves 97. A
connective tubing 79 engages the catheter 36 at the port 84 and the
connective tubing 79 can be opened or closed with one or more
valves 97. The catheter 36 comprises the one or more placement
wings 95 to assist in the placement of the catheter 36.
[0043] The catheter 36 is a thin, flexible, hollow tube that is
small enough to be threaded through a vein or an artery to deliver
fluids into or withdraw fluids from a body. The catheter 36
provides a pathway for drugs, nutrients or blood products. Patients
generally do not feel the movement of the catheter 36 through their
body. Once in place, the catheter 36 allows a number of tests or
other treatment procedures to be performed. Those skilled in the
art will recognize that many catheters known in the art can be used
with the present invention and still be within the spirit and scope
of the present invention.
[0044] The catheter 36 of the ultrasonic medical device 11
surrounds a length of the longitudinal axis of the ultrasonic probe
15. In an embodiment of the present invention shown in FIG. 3, the
catheter 36 spans a length of the ultrasonic probe 15 along the
first defined interval 26 and the second defined interval 28. In
another embodiment of the present invention, the catheter 36 spans
a length of the ultrasonic probe 15 along the second defined
interval 28. In another embodiment of the present invention, the
catheter 36 spans a length of the ultrasonic probe 15 along the
first defined interval 26. Those skilled in the art will recognize
the catheter 36 can span any length of the ultrasonic probe 15 and
be within the spirit and scope of the present invention.
[0045] The probe tip 9 can be any shape including, but not limited
to, bent, a ball or larger shapes. In one embodiment of the present
invention, the ultrasonic energy source 99 is a physical part of
the ultrasonic medical device 11. In another embodiment of the
present invention, the ultrasonic energy source 99 is not a
physical part of the ultrasonic medical device 11.
[0046] The handle 88 surrounds the transducer located between the
proximal end 31 of the ultrasonic probe 15 and the connector 93. In
a preferred embodiment of the present invention, the transducer
includes, but is not limited to a horn, an electrode, an insulator,
a backnut, a washer, a piezo microphone, and a piezo drive. The
transducer converts electrical energy provided by the ultrasonic
energy source 99 to mechanical energy. The transducer transmits
ultrasonic energy received from the ultrasonic energy source 99 to
the ultrasonic probe 15. Energy from the ultrasonic energy source
99 is transmitted along the longitudinal axis of the ultrasonic
probe 15, causing the ultrasonic probe 15 to vibrate in a
transverse mode. The transducer is capable of engaging the
ultrasonic probe 15 at the proximal end 31 with sufficient
restraint to form an acoustical mass that can propagate the
ultrasonic energy provided by the ultrasonic energy source 99.
[0047] The ultrasonic probe 15 has a stiffness that gives the
ultrasonic probe 15 a flexibility so it can be articulated in the
vasculature 44 of the body. In a preferred embodiment of the
present invention shown in FIG. 1, the ultrasonic probe 15 is a
wire. In a preferred embodiment of the present invention shown in
FIG. 1, the diameter of the ultrasonic probe 15 decreases from the
first defined interval 26 to the second defined interval 28. In
another embodiment of the present invention, the diameter of the
ultrasonic probe 15 decreases at greater than two defined
intervals. In a preferred embodiment of the present invention, the
diameter transitions 82 of the ultrasonic probe 15 are tapered to
gradually change the diameter from the proximal end 31 to the
distal end 24 along the longitudinal axis of the ultrasonic probe
15. In another embodiment of the present invention, the diameter
transitions 82 of the ultrasonic probe 15 are stepwise to change
the diameter from the proximal end 31 to the distal end 24 along
the longitudinal axis of the ultrasonic probe 15. Those skilled in
the art will recognize that there can be any number of defined
intervals and diameter transitions and that the diameter
transitions can be of any shape known in the art and be within the
spirit and scope of the present invention.
[0048] In a preferred embodiment of the present invention shown in
FIG. 2, a cross section of the ultrasonic probe 15 is circular. In
other embodiments of the present invention, the shape of the cross
section of the ultrasonic probe 15 includes, but is not limited to,
square, trapezoidal, oval, triangular, circular with a flat spot
and similar cross sections. Those skilled in the art will recognize
that other cross sectional geometric configurations known in the
art would be within the spirit and scope of the present
invention.
[0049] The pharmacological agent is advanced through the connective
tubing 79, the one or more valves 97 are opened and the
pharmacological agent moves through the catheter 36 and out the
plurality of fenestrations 13. In a preferred embodiment of the
invention, the pharmacological agent moves through the plurality of
fenestrations 13 along the length of the catheter 36 and is
approximately uniformly distributed to the occlusion 16. In a
preferred embodiment of the present invention, the occlusion 16
comprises a biological material. In a preferred embodiment of the
present invention, the occlusion 16 is a vascular occlusion 16. The
movement of the pharmacological agent allows the pharmacological
agent to become localized at the occlusion 16 in an approximately
uniform distribution to the occlusion 16. The pharmacological agent
treats the occlusion 16 at the site of the occlusion 16 and
enhances an occlusion treating effect of the ultrasonic probe 15.
After the pharmacological agent is distributed to the occlusion 16,
the ultrasonic energy source 99 is activated and energy is
transmitted along the longitudinal axis of the ultrasonic probe 15
and the ultrasonic probe 15 vibrates in a transverse mode.
[0050] The transverse mode of vibration of the ultrasonic probe 15
according to the present invention differs from an axial (or
longitudinal) mode of vibration disclosed in the prior art. Rather
than vibrating in an axial direction, the ultrasonic probe 15 of
the present invention vibrates in a direction transverse (not
parallel) to the axial direction. As a consequence of the
transverse vibration of the ultrasonic probe 15, the occlusion
destroying effects of the ultrasonic medical device 11 are not
limited to those regions of the ultrasonic probe 15 that may come
into contact with the occlusion 16. Rather, as a section of the
longitudinal axis of the ultrasonic probe 15 is positioned in
proximity to an occlusion, a diseased area or lesion, the occlusion
16 is removed in all areas adjacent to a plurality of energetic
transverse nodes and transverse anti-nodes that are produced along
a portion of the longitudinal axis of the ultrasonic probe 15,
typically in a region having a radius of up to about 6 mm around
the ultrasonic probe 15.
[0051] Transversely vibrating ultrasonic probes for occlusion
treatment are described in the Assignee's co-pending patent
applications U.S. Ser. No. 09/776,015, now U.S. Pat. No. 6,652,547;
U.S. Ser. No. 09/618,352, now U.S. Pat. No. 6,551,337; and U.S.
Ser. No. 09/917,471, now U.S. Pat. No. 6,695,781, which further
describe the design parameters for such an ultrasonic probe and its
use in ultrasonic devices for a treatment, and the entirety of
these applications are hereby incorporated herein by reference.
[0052] FIG. 4 illustrates an alternative embodiment of the
ultrasonic medical device 11 wherein the ultrasonic probe 15
comprises an approximately uniform diameter. The ultrasonic probe
15 comprises a plurality of transverse nodes 40 and transverse
anti-nodes 42 at repeating intervals along a portion of the
longitudinal axis of the ultrasonic probe 15.
[0053] A length and the cross section of the ultrasonic probe 15
are sized to support the transverse ultrasonic vibration with a
plurality of transverse nodes 40 and transverse anti-nodes 42 along
the portion of the longitudinal axis of the ultrasonic probe 15. In
a preferred embodiment of the present invention, more than one of
the plurality of transverse anti-nodes 42 are in communication with
the occlusion 16. The transverse ultrasonic vibration produces the
plurality of transverse nodes 40 and transverse anti-nodes 42 along
the portion of the longitudinal axis of the ultrasonic probe 15.
The transverse nodes 40 are areas of minimum energy and minimum
vibration. A plurality of transverse anti-nodes 42, or areas of
maximum energy and maximum vibration, also occur at repeating
intervals along the portion of the longitudinal axis of the
ultrasonic probe 15. The number of transverse nodes 40 and
transverse anti-nodes 42, and the spacing of the transverse nodes
40 and transverse anti-nodes 42 of the ultrasonic probe 15 depend
on the frequency of the energy produced by the ultrasonic energy
source 99. The separation of the transverse nodes 40 and the
transverse anti-nodes 42 is a function of the frequency, and can be
affected by tuning the ultrasonic probe 15. In a properly tuned
ultrasonic probe 15, the transverse anti-nodes 42 will be found at
a position exactly one-half of the distance between the transverse
nodes 40 located adjacent to each side of the transverse anti-nodes
42.
[0054] As a consequence of the transverse vibration of the
ultrasonic probe 15, the occlusion destroying effects of the
ultrasonic medical device 11 are not limited to those regions of
the probe 15 that may come into contact with the occlusion 16.
Rather, as the ultrasonic probe 15 is swept through an area of the
occlusion 16, preferably in a windshield-wiper fashion, the
occlusion 16 is removed in all areas adjacent to the plurality of
transverse anti-nodes 42 being produced along the portion of the
longitudinal axis of the ultrasonic probe 15. The extent of a
cavitational energy produced by the ultrasonic probe 15 is such
that the cavitational energy extends radially outward from the
longitudinal axis of the ultrasonic probe 15 at the transverse
anti-nodes 42 along the longitudinal axis of the ultrasonic probe
15. In this way, actual treatment time using the transverse mode
ultrasonic medical device 11 according to the present invention is
greatly reduced as compared to methods disclosed in the prior art
that primarily utilize longitudinal vibration (along the axis of
the ultrasonic probe) for treatment of the occlusion. Utilizing
longitudinal vibration limits treatment to the tip of the probe in
prior art devices.
[0055] The use of the pharmacological agent in combination with the
transverse vibration of the ultrasonic probe 15 enhances the
occlusion treating effect of the present invention, causing the
occlusion 16 to be broken up into a particulate. Some of the
occlusion 16 may be completely removed from the vasculature 44 at
the site of the occlusion 16 while some may reside in the
vasculature 44 as a particulate downstream of the site of the
occlusion 16. Sizes of the particulate vary from a small size that
can be easily absorbed and discharged through the body in
conventional ways to a size that may have a risk of a subsequent
occlusion 16 formation downstream. The pharmacological agent treats
the occlusion 16 and a portion of the occlusion 16 may be removed
while the particulate is created. The removal of the occlusion 16
and the breaking up of the occlusion 16 into the particulate is
done through a generation of multiple cavitational transverse
anti-nodes 42 along the portion of the longitudinal axis of the
ultrasonic probe 15 not parallel to the longitudinal axis of the
ultrasonic probe 15. Since substantially larger affected areas can
be denuded of the occlusion 16 in a short time, actual treatment
time using the transverse mode ultrasonic medical device 11
according to the present invention is greatly reduced as compared
to methods using prior art probes that primarily utilize
longitudinal vibration (along the axis of the probe) for ablation.
A distinguishing feature of the present invention is the ability to
utilize ultrasonic probes 15 of extremely small diameter compared
to prior art probes, without loss of efficiency, because the
occlusion fragmentation process is not dependent on the area of the
probe tip 9. Highly flexible ultrasonic probes 15 can therefore be
designed to mimic device shapes that enable facile insertion into
occlusion spaces or extremely narrow interstices that contain the
material comprising the occlusion 16. Another advantage provided by
the present invention is the ability to remove the occlusion 16
from large areas within cylindrical or tubular surfaces.
[0056] The pharmacological agent continues to travel downstream of
the site of the occlusion 16 and continues to treat the
particulate. The sizes of the particulate that are created by the
fragmentation of the occlusion 16 may cause a formation of an
occlusion 16 downstream from the treatment site. With the
ultrasonic energy source 99 activated and the pharmacological agent
continuing to travel downstream of the site of the occlusion 16 to
treat the particulate, the remaining particulate is broken down
further into an aggregate. The particulate and aggregate are
similar in size to red blood cells. The size of the aggregate is
such that the aggregate is easily discharged from the body through
conventional ways or simply dissolves into the blood stream. A
conventional way of discharging the aggregate from the body
includes transferring the aggregate through the blood stream to the
kidney where the aggregate is excreted as bodily waste. The
combination effects of the transverse vibrations of the ultrasonic
probe 15 with the pharmacological agent provides for ablation of
the occlusion 16.
[0057] A significant advantage of the present invention is that the
ultrasonic medical device 11 physically destroys and removes the
material comprising the occlusion 16 (especially adipose or other
high water content tissue) through the mechanism of non-thermal
cavitation. In a preferred embodiment of the present invention, the
occlusion 16 comprises a biological material. In a preferred
embodiment of the present invention, the occlusion 16 is a vascular
occlusion 16. Cavitation is a process in which small voids are
formed in a surrounding fluid through the rapid motion of the
ultrasonic probe 15 and the voids are subsequently forced to
compress. The compression of the voids creates a wave of acoustic
energy which acts to dissolve the matrix binding together the
occlusion 16, while having no damaging effects on healthy tissue.
The ultrasonic energy source 99 provides a low power electric
signal of approximately 2 watts to the transducer, which then
transforms the electric signal into acoustic energy. Longitudinal
motion created within the transducer is converted into a standing
transverse wave along the portion of the longitudinal axis of the
ultrasonic probe 15, which generates acoustic energy in the
surrounding medium through cavitation. The acoustic energy
dissolves the matrix of the occlusion 16.
[0058] The ultrasonic energy produced by the ultrasonic probe 15 is
in the form of very intense, high frequency sound vibrations that
result in physical reactions in the water molecules within a body
tissue or surrounding fluids in proximity to the ultrasonic probe
15. These reactions ultimately result in a process called
"cavitation," which can be thought of as a form of cold (i.e.,
non-thermal) boiling of the water in the body tissue, such that
microscopic voids are rapidly created and destroyed in the water
creating cavities in their wake. As surrounding water molecules
rush in to fill the cavity created by the collapsed voids, they
collide with each other with great force. Cavitation results in
shock waves running outward from the collapsed voids which can wear
away or destroy material such as surrounding tissue in the vicinity
of the ultrasonic probe 15.
[0059] The removal of the occlusion 16 by cavitation and the
treatment of the pharmacological agent also provides the ability to
remove large volumes of material comprising the occlusion 16 with
the small diameter ultrasonic probe 15, while not affecting healthy
tissue. The use of the pharmacological agent and cavitation as the
mechanism for destroying the occlusion 16 allows the present
invention to destroy and remove the material comprising the
occlusion 16 within a range of temperatures of about .+-.7.degree.
C. from normal body temperature. Therefore, complications attendant
with the use of thermal destruction or necrosis, such as swelling
or edema, as well as loss of elasticity are avoided.
[0060] The number of transverse nodes 40 and transverse anti-nodes
42 occurring along the longitudinal axis of the ultrasonic probe 15
is modulated by changing the frequency of energy supplied by the
ultrasonic energy source 99. The exact frequency, however, is not
critical and for the ultrasonic probe 15, the ultrasonic energy
source 99 run at, for example, about 20 kHz is generally sufficient
to create an effective number of occlusion destroying transverse
anti-nodes 42 along the longitudinal axis of the ultrasonic probe
15. The low frequency requirements of the present invention is a
further advantage in that the low frequency requirement leads to
less damage to healthy tissue. Those skilled in the art understand
it is possible to adjust the dimensions of the ultrasonic probe 15,
including diameter, length and distance to the ultrasonic energy
source 99, in order to affect the number and spacing of the
transverse nodes 40 and transverse anti-nodes 42 along a portion of
the longitudinal axis of the ultrasonic probe 15.
[0061] The present invention allows the use of ultrasonic energy to
be applied to occlusions 16 selectively, because the ultrasonic
probe 15 conducts energy across a frequency range from about 20 kHz
through about 80 kHz. The amount of ultrasonic energy to be applied
to a particular treatment site is a function of the amplitude and
frequency of vibration of the ultrasonic probe 15. In general, the
amplitude or throw rate of the energy is in the range of about 25
microns to about 250 microns, and the frequency in the range of
about 20 kHz to about 80 kHz. In a preferred embodiment of the
present invention, the frequency of ultrasonic energy is from about
20 kHz to about 35 kHz. Frequencies in this range are specifically
destructive of occlusions 16 including, but not limited to,
hydrated (water-laden) tissues such as endothelial tissues, while
substantially ineffective toward high-collagen connective tissue,
or other fibrous tissues including, but not limited to, vascular
tissues, epidermal, or muscle tissues.
[0062] The amount of cavitation energy to be applied to a
particular site requiring treatment is a function of the amplitude
and frequency of vibration of the ultrasonic probe 15, the
longitudinal length of the ultrasonic probe 15, the geometry at the
distal end 24 of the ultrasonic probe 15, the proximity of the
ultrasonic probe 15 to the occlusion 16, and the degree to which
the length of the ultrasonic probe 15 is exposed to the occlusion
16. Reducing the amount of energy from the ultrasonic source can
reduce the amount of damage to healthy tissue.
[0063] In a preferred embodiment of the present invention, the
transducer transmits ultrasonic energy from the ultrasonic energy
source 99 to the longitudinal axis of the ultrasonic probe 15 to
oscillate the ultrasonic probe 15 in a direction transverse to its
longitudinal axis. In a preferred embodiment of the present
invention, the transducer is a piezoelectric transducer that is
coupled to the ultrasonic probe 15 to enable transfer of ultrasonic
excitation energy and cause the ultrasonic probe 15 to oscillate in
the transverse direction relative to the longitudinal axis. In an
alternative embodiment of the present invention, a
magneto-strictive transducer may be used for transmission of the
ultrasonic energy.
[0064] In a preferred embodiment of the present invention, the
pharmacological agent is tissue plasminogen activator (tPA). tPA is
a thrombolytic agent that breaks up or dissolves blood clots. tPA
has been approved by the Food and Drug Administration since 1996
for the treatment of stroke and heart attack. tPA acts in a two
stage process to dissolve fibrin clots that may be found in a
vasculature of the body. Fibrin can be split up by plasmin, where a
multitude of plasmin molecules can diffuse through aqueous channels
in the fibrin clot to cut the connector rods that comprise the
fibrin. In order to form plasmin, tPA binds to a component of the
clot called fibrin and activates plasminogen to form plasmin.
Plasmin degrades components of the clot and other proteins that
promote the blood clotting.
[0065] There are several other pharmacological agents that treat
occlusions 16 and can be used for the present invention.
Antiplatelet agents prevent a formation of blood platelets, a
collection of small blood cells having a disc shape. Blood
platelets are an important component to the blood clotting process
with the blood platelets collecting to form a blood clot. Aspirin
is the most common antiplatelet agent that is used to prevent
clots. Aspirin is also known as a nonsteroidal anti-inflammatory
agent that stops blood platelets from sticking together and forming
a blood clot. Glycoprotein inhibitors are potent blood thinning
agents that block platelets and include abciximab, Eptifibatide,
tirofiban and lamifiban. Thienopyrindines are oral platelet
inhibitors and include clopidogrel and ticlopidine. Anticoagulants,
including heparin and warfarin are also used to help thin blood.
Lysing agents work to break up or disintegrate the occlusion 16.
Dipyridamole is similar to aspirin in that it inhibits platelet
adhesion, and thus tends to prevent the vascular thrombosis of
heart attacks and strokes. Hirudin is an anticoagulant peptide
whose anticoagulant activity comes from the chemical ability to
inhibit thrombus formation. Urokinase and streptokinase,
thrombolytic agents similar to tPA, work by activating the body's
own fibrinolytic system by activating the production of plasmin
from plasminogen. Those skilled in the art will recognize there are
other pharmacological agents known in the art that can be used to
treat occlusions that are within the spirit and scope of the
present invention.
[0066] The ultrasonic probe 15 is designed to have the cross
section with a small profile, which also allows the ultrasonic
probe 15 to flex along its length, thereby allowing the ultrasonic
probe 15 to be used in a minimally invasive manner. A significant
feature of the present invention resulting from the transversely
generated energy is the retrograde movement of biological material,
e.g., away from the probe tip 9 and along the longitudinal axis of
the ultrasonic probe 15.
[0067] In a preferred embodiment of the present invention, the
ultrasonic probe 15 has a small diameter. In a preferred embodiment
of the present invention, the diameter of the ultrasonic probe 15
gradually decreases from the proximal end 31 to the distal end 24.
In an embodiment of the present invention, the diameter of the
distal end 24 of the ultrasonic probe 15 is about 0.004 inches. In
another embodiment of the present invention, the diameter of the
distal end 24 of the ultrasonic probe 15 is about 0.015 inches. In
other embodiments of the present invention, the diameter of the
distal end 24 of the ultrasonic probe 15 varies between about 0.003
inches and about 0.025 inches. Those skilled in the art will
recognize an ultrasonic probe 15 can have a diameter at the distal
end 24 smaller than about 0.003 inches, larger than about 0.025
inches, and between about 0.003 inches and about 0.025 inches and
be within the spirit and scope of the present invention.
[0068] In an embodiment of the present invention, the diameter of
the proximal end 31 of the ultrasonic probe 15 is about 0.012
inches. In another embodiment of the present invention, the
diameter of the proximal end 31 of the ultrasonic probe 15 is about
0.025 inches. In other embodiments of the present invention, the
diameter of the proximal end 31 of the ultrasonic probe 15 varies
between about 0.003 inches and about 0.025 inches. Those skilled in
the art will recognize the ultrasonic probe 15 can have a diameter
at the proximal end 31 smaller than about 0.003 inches, larger than
about 0.025 inches, and between about 0.003 inches and about 0.025
inches and be within the spirit and scope of the present
invention.
[0069] In an embodiment of the present invention, the diameter of
the ultrasonic probe 15 is approximately uniform from the proximal
end 31 to the distal end 24 of the ultrasonic probe 15. In another
embodiment of the present invention, the diameter of the ultrasonic
probe 15 gradually decreases from the proximal end 31 to the distal
end 24. In an embodiment of the present invention, the ultrasonic
probe 15 may resemble a wire. In an embodiment of the present
invention, the gradual change of the diameter from the proximal end
31 to the distal end 24 occurs over the at least one diameter
transitions 82 with each diameter transition 82 having an
approximately equal length. In another embodiment of the present
invention, the gradual change of the diameter from the proximal end
31 to the distal end 24 occurs over a plurality of diameter
transitions 82 with each diameter transition 82 having a varying
length. The diameter transition 82 refers to a section where the
diameter varies from a first diameter to a second diameter.
[0070] The length of the ultrasonic probe 15 of the present
invention is chosen so as to be resonant in a transverse mode. In
an embodiment of the present invention, the ultrasonic probe 15 is
between about 30 centimeters and about 300 centimeters in length.
In an embodiment of the present invention, the ultrasonic probe is
a wire. Those skilled in the art will recognize an ultrasonic probe
can have a length shorter than about 30 centimeters and a length
longer than about 300 centimeters and be within the spirit and
scope of the present invention.
[0071] The ultrasonic probe 15 is inserted into a vasculature 44 of
the body and may be disposed of after use. In a preferred
embodiment of the present invention, the ultrasonic probe 15 is for
a single use and on a single patient. In a preferred embodiment of
the present invention, the ultrasonic probe 15 is disposable. In
another embodiment of the present invention, the ultrasonic probe
15 can be used multiple times.
[0072] FIG. 5 shows a fragmentary side view of the ultrasonic probe
15 within the catheter 36. The ultrasonic probe 15 comprises the
distal end 24 and the probe tip 9. The catheter comprises the
plurality of fenestrations 13 at the distal end 34 of the catheter
36. In the embodiment of the present invention shown in FIG. 5, the
distal end 24 with the probe tip 9 of the ultrasonic probe 15 is
within the catheter 36. There is an open area 19 between the
ultrasonic probe 15 and the catheter 36. The pharmacological agent
is advanced between the open area 19 and moves through the
plurality of fenestrations 13.
[0073] FIG. 6 shows a fragmentary side view of the ultrasonic probe
15 within the catheter 36 wherein the section of the longitudinal
axis of the ultrasonic probe 15 extends past a distal end 34 of the
catheter.
[0074] The present invention also provides a method of treating an
occlusion 16 through a combination of the ultrasonic probe 15 and
the pharmacological agent. The ultrasonic probe 15 is inserted into
the vasculature 44 of the body and the catheter 36 is delivered
over a length of the longitudinal axis of the ultrasonic probe 15
as shown in FIG. 5. In another embodiment of the present invention,
the catheter 36 is inserted into the vasculature 44 of the body and
the ultrasonic probe 15 is moved within the catheter 36. As the
catheter 36 is inserted into the vasculature 44, the placement
wings 95 engage the patient's skin to secure the catheter 36. The
connecting tube 79 is opened by the one or more valves 97 and a
pharmacological agent is released through the catheter 36 into the
open area 19 between the ultrasonic probe 15 and the catheter 36.
The pharmacological agent engages the occlusion 16. A section of
the longitudinal axis of the ultrasonic probe 15 is advanced past a
distal end 34 of the catheter as shown in FIG. 6. The section of
the longitudinal axis of the ultrasonic probe 15 is exposed to the
occlusion 16 and the ultrasonic source 99 is activated. In one
embodiment of the present invention, the section of the
longitudinal axis of the ultrasonic probe 15 is exposed by pushing
the section of the longitudinal axis of the ultrasonic probe 15
past the distal end 34 of the catheter 36. In another embodiment of
the present invention, the section of the longitudinal axis of the
ultrasonic probe 15 is exposed by pulling back on the catheter 36.
The pharmacological agent enhances an occlusion treating effect of
the ultrasonic probe 15 by working in combination with the
ultrasonic probe 15 at the site of the occlusion 16 and downstream
of the site of the occlusion 16. The combination of the ultrasonic
energy from the ultrasonic probe 15 and the pharmacological agent
breaks up the occlusion 16 into the particulate that is carried by
the blood stream downstream of the site of the occlusion 16. Sizes
of the particulate vary from a smallest size that can be easily
absorbed and discharged through the body in conventional ways to a
size that may have a risk of a subsequent occlusion 16 formation
downstream. The combination of the ultrasonic energy from the
ultrasonic probe 15 and the pharmacological agent further breaks up
the particulate into an aggregate downstream of the particulate.
The size of the aggregate is such that the aggregate is easily
discharged from the body in conventional ways or is simply
dissolved into the blood stream.
[0075] The use of the pharmacological agent in conjunction with the
ultrasonic probe 15 is a reliable method of effecting removing the
occlusion 16 that is also cost effective. In addition to suffering
from complications and not being effective when used alone, the use
of pharmacological agents alone requires a large quantity of the
pharmacological agent to treat the occlusion 16. The present
invention requires a lower quantity of the pharmacological agent
due to the combinational effects of the pharmacological agent with
the ultrasonic probe 15. The lower amount of the pharmacological
agent translates into a more cost effective solution that also
includes the added benefit of more effective occlusion 16
removal.
[0076] The present invention also provides a method of removing an
occlusion 16 by moving the ultrasonic probe 15 through the
vasculature 44 to the site of the occlusion 16 and releasing a
pharmacological agent in the vasculature 44. An ultrasonic energy
source is activated and the longitudinal axis of the ultrasonic
probe 15 is vibrated in the transverse direction. The
pharmacological agent enhances an occlusion destroying effect of
the ultrasonic probe 15. The pharmacological agent engages the
occlusion 16 and moves downstream of the site of the occlusion 16
with the particulate. While moving downstream, the pharmacological
agent continues to break up the particulate to the aggregate.
[0077] The present invention provides an apparatus and a method for
more completely removing an occlusion 16 by using a pharmacological
agent in conjunction with an ultrasonic probe 15 to enhance an
occlusion treating effect of the ultrasonic probe 15. The
pharmacological agent is delivered through a plurality of
fenestrations 13 of the catheter 36 and treats the occlusion 16 at
the site of the occlusion 16 and continues to travel downstream of
the site of the occlusion 16. The combination of the
pharmacological agent and the transverse vibrations of the
ultrasonic probe 15 breaks up the occlusion 16 into a particulate
downstream of the site of the occlusion 16 and continues to treat
the particulate and breaks up the particulate into an aggregate to
a size that is easily removed from the body in conventional ways.
The present invention provides an apparatus and a method for more
completely removing an occlusion that is safe, simple, efficient,
effective, user-friendly, reliable and cost effective.
[0078] All patents, patent applications, and published references
cited herein are hereby incorporated herein by reference in their
entirety. While this invention has been particularly shown and
described with references to preferred embodiments thereof, it will
be understood by those skilled in the art that various changes in
form and details may be made therein without departing from the
scope of the invention encompassed by the appended claims.
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