Surgery – Means for introducing or removing material from body for... – With means for cutting – scarifying – or vibrating tissue
Reexamination Certificate
1997-11-13
2001-02-06
Dawson, Glenn K. (Department: 3762)
Surgery
Means for introducing or removing material from body for...
With means for cutting, scarifying, or vibrating tissue
C606S159000
Reexamination Certificate
active
06183432
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to guide wires and catheters for crossing, opening and/or widening a channel through a totally or partially occluded biological vessel, such as a blood vessel.
2. Description of the Related Art
There are a number of disease conditions involving stenosis, which is the narrowing or obstruction of the interior passage, or lumen, of arteries. These obstructions, generally known as occlusions, are found in patients suffering from atherosclerosis, a condition characterized by an accumulation of fibrous, fatty or calcified tissue in the arteries. As these occlusions can partially or totally block the arterial flow, they can be potentially life threatening. Occlusions may be partial or total, may be soft and pliable or hard and calcified, and may be found at a great variety of sites in the arterial system, including the aorta, the coronary and carotid arteries, and peripheral arteries.
Although the majority of interventional procedures such as balloon angioplasty, atherectomy, and the like bring some degree of relief to the patient and improvement in the blood flow, total or near total occlusions are difficult to treat, as the interventional tool, such as the angioplasty balloon or the atherectomy catheter, often cannot reach and cross the occlusion site to carry out their intended functions. This is generally referred to as an inability to cross, and is the major cause of failure of such procedures.
A number of different instruments have been proposed to open or to cross a totally or partially blocked blood vessel. One such instrument is disclosed in U.S. Pat. No. 5,116,350 to Stevens. Stevens describes a catheter whose distal blunt tip moves back and forth in a ramming motion or whose cutting/abrading distal tip moves back and forth about an axis. Osypka, in U.S. Pat. No. 5,234,451 discloses an apparatus for eliminating occlusions and stenoses in body cavities. The device of Osypka includes a combination of anvil and reciprocating internal hammer to ram the device through occlusions. The hammer repeatedly strikes the anvil to drive the device further within the cavity. Uflacker et al., in U.S. Pat. No. 5,243,997 propose a device to vibrate a guidewire. The vibration induced thereon is asserted to facilitate the pushing of the guidewire past the obstruction. Solar, in U.S. Pat. No. 5,549,119 discloses a vibrating tip catheter, the vibration being asserted to enhance the catheter's ability to cross tight lesions and stenoses.
These devices, however, suffer from a number of disadvantages. It is believed that the sharp back and forth ramming motions of some of these devices may possibly damage the vessel lining and lead to unwanted scar tissue. On the other hand, the vibrating guide wires and tips are not believed wholly effective in crossing total occlusions without damaging the vessel walls. Moreover, it is not believed that these devices possess the ability to sufficiently enlarge an existing channel to allow other, larger, or more aggressive interventional tools to follow and to position themselves across the occlusion.
What is needed, therefore, are improved guide wires and catheters that are able to successfully navigate tortuous regions of a patient's vasculature and to create or enlarge a channel past an occlusion to allow other interventional tools to successfully perform their intended therapeutic functions. What is also needed are such guide wires and catheters that are effective in opening or enlarging channels past an occlusion, while not damaging the vessel walls.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide improved guide wires and catheters that are able to successfully navigate tortuous regions of a patient's vasculature and to create or enlarge a channel to allow other interventional tools to successfully cross the lesion.
It is a further object of the present invention to provide such guide wires and catheters that are effective in opening or enlarging channels past an occlusion, while not damaging the vessel walls.
In accordance with the above objects and those that will be mentioned and will become apparent below, the guidewire for crossing vascular occlusions according to an embodiment of the present invention comprises:
a guidewire shaft having a proximal end and a distal end;
a drive member having a proximal and a distal end, the drive member being rotatably disposed within and along a longitudinal axis of the guidewire shaft;
an actuator connected to the proximal end of the drive member, the actuator imparting a rotation to the drive member;
an asymmetrical rotating tip attached to the distal end of the drive member and driven in rotation about the longitudinal axis of the guidewire shaft by the drive member, the asymmetrical rotating tip including a protruding portion that projects from a plane defined by an outer surface of the guidewire shaft to render the rotating tip asymmetrical with respect to the longitudinal axis of the shaft. In this manner, the protruding portion creates a volume of revolution as the asymmetrical tip rotates, which facilitates crossing a vascular occlusion.
The asymmetrical rotating tip may includes an ultrasonic transducer or an optical fiber device mounted therein, to thereby obtain guidance information as the guidewire advances through the patient's vasculature. The drive member may be a drive shaft having a lumen therethrough to accommodate electrical leads connected to the ultrasonic transducer or the optical fiber, connected to an imaging device near the proximal end of the guidewire shaft. The ultrasonic transducer may be recessed within a well disposed within the asymmetrical rotating tip. The protruding portion of the asymmetrical rotating tip may project from the outer surface of the guidewire shaft by a distance selected within a range of 0.002 inches to 0.010 inches. The actuator may be a motorized actuator, a manual actuator, or a combination of these. The guidewire shaft may include a coiled wire and a polymeric tube in intimate contact with an outer diameter of the coil. In this manner, the tube in intimate contact with the coil prevents the coiled wire from buckling in or out when the guidewire is pushed through the patient's vasculature, thereby increasing the pushability and the column strength of the guidewire without substantially reducing its flexibility. The tube may be formed of, for example, polyimide or heat shrinkable TEFLON. A coupling member may be disposed between the distal end of the guidewire shaft and the asymmetrical rotating tip, the coupling member being bonded to the distal end of the shaft by an adhesive.
According to another exemplary embodiment of the present invention, a guidewire for crossing a vascular occlusion, comprises:
a guidewire shaft having a proximal end and a distal end;
a rotating drive member having a proximal and a distal end;
a coupling member attached to a distal end of the shaft, and having a through opening aligned with a longitudinal axis of the guidewire shaft to allow the drive member to rotate and slide therein, the coupling member including a distal angled surface oriented at predetermined acute angle relative to a plane perpendicular to the longitudinal axis of the guidewire shaft; and
an asymmetrical tip attached to the distal end of the drive member and driven in rotation about the longitudinal axis of the guidewire shaft by the drive member, the asymmetrical tip including a proximal angled surface that, in one orientation, is parallel to and in intimate contact with the distal angled surface of the coupling member. In this manner, rotation of the asymmetrical tip against the distal angled surface of the coupling member causes the asymmetrical tip to reciprocate along the axis of the guidewire shaft over a distance determined at least by the predetermined angle, to thereby facilitate a crossing of a vascular occlusion by submitting the occlusion to both rotational and reciprocating movement of the asymmetrical tip.
A spring
Dawson Glenn K.
Hayes Michael J.
LuMend, Inc.
Wilson Sonsini Goodrich & Rosati
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