Surgery – Instruments – Internal pressure applicator
Reexamination Certificate
2000-03-21
2002-11-26
Look, Edward K. (Department: 3745)
Surgery
Instruments
Internal pressure applicator
C606S200000, C604S101010, C604S101030, C604S101050, C604S103010, C604S919000
Reexamination Certificate
active
06485500
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to medical devices, and more particularly concerns systems and methods for containing, aspirating and removing emboli from blood vessels, and especially during interventional procedures treatment of cerebral blood vessels such as carotid arteries to prevent emboli or debris from entering and occluding downstream blood vessels leading to the brain which may cause a stroke.
2. Description of Related Art
A variety of non-surgical interventional procedures have been developed for opening stenosed or occluded blood vessels in a patient caused by the build up of plaque or other substances on the walls of the blood vessel. Such procedures usually involve the percutaneous introduction of the interventional device into the lumen of the artery, usually through a catheter. One widely known and medically accepted procedure is balloon angioplasty in which an inflatable balloon is introduced within the stenosed region of the blood vessel to dilate the occluded vessel. The balloon catheter is initially inserted into the patient's arterial system and is advanced and manipulated into the area of stenosis in the artery. The balloon is inflated to compress the plaque and press the vessel wall radially outward to increase the diameter of the blood vessel.
In another widely practiced procedure, the stenosis can be treated by placing a device known as a stent into the stenosed region to hold open and sometimes expand the segment of blood vessel or other arterial lumen. Stents are particularly useful in the treatment of repair of blood vessels after a stenosis has been compressed by percutaneous transluminal coronary angioplasty (PTCA), percutaneous transluminal angioplasty (PTA) or removal by atherectomy or other means. Stents are usually delivered in a compressed condition to the target site, and then are deployed at the target location into an expanded condition to support the vessel and help maintain it in an open position.
However, it has been found that stenting and angioplasty, particularly angioplasty of the cerebral vessels such as the carotid arteries, and saphenous vein graft (SVG) angioplasty, for treating veins grafted in bypass surgery, which can become diseased and bring an increased risk of generating emboli, pose risks of dislodging thrombus or friable plaque, and that such a thrombus or plaque that is dislodged during such a procedure can enter the bloodstream and subsequently migrate through the patient's vasculature to sensitive organs such as the brain, where they may induce trauma. A thrombus or pieces of plaque material can be dislodged from a stenosis by expansion of the blood vessel being treated during a balloon angioplasty procedure and become released into the bloodstream. It has also been found that during deployment of a stent, it is possible for the stent to cut into the stenosis and shear off pieces of plaque which become embolic debris that can travel downstream and lodge in the patient's vascular system.
Medical devices have been developed to attempt to deal with the problem created when debris or fragments enter the circulatory system following treatment utilizing any one of the above-identified procedures. One approach which has been attempted is the cutting of any debris into minute sizes which pose little chance of becoming occluded in major vessels within the patient's vasculature. However, it is often difficult to control the size of the fragments which are formed, and the potential risk of vessel occlusion still exists, making such procedures in the carotid arteries a high-risk proposition.
Other techniques which have been developed to address the problem of removing embolic debris include the use of catheters with a vacuum source which provides temporary suction to remove embolic debris from the bloodstream. However, as mentioned above, there have been complications with such systems since the vacuum catheter may not always remove all of the embolic material from the bloodstream, and a powerful suction could cause problems to the patient's vasculature.
Filters have been developed for trapping and preventing such embolic debris from flowing through the vasculature. Such filters are usually delivered in a collapsed configuration through the patient's vasculature, and are then expanded once in place in the patient's blood vessel to trap emboli. After emboli have been trapped, the filter can again be collapsed to remove the filter with any trapped emboli from the vessel. However, it has been found that trapped emboli can escape from such filters during the time that the filters are being collapsed and removed from the blood vessels. In other instances, the rate of blood percolating through the filtering material may be slower than the normal blood flow which can either cause the filtering material to tear or cause the filter to dislodge from the deployed position due to the build up of fluid pressure behind the filter. Moreover, should the filter become clogged with debris, there is a possibility that blood circulation past the clogged filter will be insufficient for the downstream vessels and organs. If a filter should become clogged when in use in the carotid arteries, blood flow could be diminished to the vessels leading to the brain. While the brain may be capable of functioning for a short period of time without sufficient blood flow, blood stoppage of more than thirty to forty seconds could cause the patient to experience a seizure. If the physician administering the procedure is unaware that the filtering device is clogged and that there is little or no blood flowing to the brain, the injury to the patient can be as devastating as if an emboli itself had caused blockage of the cerebral arteries.
One emboli containment system is known in which a treatment chamber is formed within a blood vessel by occlusion balloons provided on catheters on opposite sides of a stenotic lesion to prevent emboli migration during a treatment procedure, with irrigation and aspiration within the chamber through catheter pathways to remove emboli from the treatment chamber. However, that have been emboli partially dislodged and that are not removed by such irrigation and aspiration can later become free to migrate into the rest of the vasculature. It would be desirable for such a containment system to provide for turbulent flow of fluid within such a treatment chamber within the chamber, such as by jetting or streaming of the fluid in order to more thoroughly remove emboli from within the treatment chamber that may only have become partially dislodged during the treatment procedure.
What has been needed and has been heretofore unavailable are systems and methods for containing, aspirating and removing emboli that have been dislodge and partially dislodged from blood vessels in conjunction with such interventional procedures as stenting and balloon angioplasty of blood vessels, for minimizing the risk of embolic migration during and after the interventional procedures. The present invention meets these and other needs.
SUMMARY OF THE INVENTION
Briefly, and in general terms, the present invention provides for a system and method for isolation of a section of a blood vessel to prevent migration of emboli from the section during an interventional procedure, and subsequent flushing of the section to remove any emboli dislodged during the procedure. As used in the description of the present invention, the terms “proximal” and “proximal direction” are intended to mean moving away from the heart of a patient or out of the patient, and the terms “distal” and “distal direction” are intended to mean moving toward the heart of a patient, or into the patient. These definitions will apply with reference to body lumens and apparatus, such as catheters, guide wires, and stents.
Accordingly, in one presently preferred embodiment, the present invention provides for an emboli protection system, comprising a distal blocking balloon catheter and a proximal blocking balloon cathe
Huter Benjamin C.
Jackson Gregg A.
Kokish Arkady
Mirzaee Daryush
Penn Eric J.
Advanced Cardiovascular Systems Inc.
Edgar Richard A.
Fulwider Patton Lee & Utecht LLP
Look Edward K.
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