Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2001-07-31
2004-12-28
Tranh, LoAn H. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S916000
Reexamination Certificate
active
06835188
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a system and methods for inducing cardioplegic arrest and for performing cardiopulmonary bypass procedures. More particularly, the invention relates to an aortic catheter having a porous aortic root balloon for controlling flow through the coronary arteries and the aortic lumen, and for inducing cardiac arrest. The invention further relates to devices for maintaining the competence of a patient's aortic valve and for preventing unwanted flow through the aortic valve.
BACKGROUND OF THE INVENTION
Recent advances in the field of minimally invasive cardiac surgery have included the development of aortic catheters and methods for inducing cardiac arrest without the necessity of opening the patient's chest with a sternotomy or other major thoracotomy. For example, U.S. Pat. No. RE 35,352 to Peters describes a single balloon catheter for occluding a patient's ascending aorta and a method for inducing cardioplegic arrest. A perfusion lumen or contralateral arterial cannula is provided for supplying oxygenated blood during cardiopulmonary bypass. U.S. Pat. No. 5,584,803 to Stevens et al. describes a single balloon catheter for inducing cardioplegic arrest and a system for providing cardiopulmonary support during closed chest cardiac surgery. A coaxial arterial cannula is provided for supplying oxygenated blood during cardiopulmonary bypass. The occlusion balloon of these catheters must be very carefully placed in the ascending aorta between the coronary arteries and the brachiocephalic artery, therefore the position of the catheter must be continuously monitored to avoid complications.
In clinical use, in patients with incompetent or regurgitant aortic valves, antegrade infusion of cardioplegia by aortic root injection is contraindicated because the pressure generated by infusion of cardioplegia overcomes the reduced competence of the valve, causing cardioplegia to enter the ventricle rather than entering the coronary arteries. In some cases the left ventricle may become distended. In patients with incompetent or regurgitant aortic valves, it is recommended that cardioplegia be administered by direct coronary cannulation or by retrograde perfusion through the coronary sinus. Direct coronary cannulation can be difficult and can dislodge plaques from ostial lesions in the coronary arteries. Retrograde perfusion of cardioplegia through the venous system has been used successfully, however, there is debate as to the effectiveness of this procedure, and correct placement of the catheters can be difficult. Furthermore, even in patients with normal aortic valves, pressures generated during surgery may cause the valve to become temporarily incompetent, leading to problems similar to those discussed above.
Another difficulty encountered with prior art aortic catheters is the tendency of the single balloon catheters to migrate or drift in the direction of the pressure gradient within the aorta. Specifically, during infusion of cardioplegia, the balloon catheter will tend to drift downstream away from the heart and toward the aortic arch and, while the cardiopulmonary bypass pump is on during the procedure and after completion of infusion of cardioplegia, the balloon catheter will tend to drift upstream in the opposite direction toward the heart into the aortic root. This migration can be problematic if the balloon drifts downstream far enough to occlude the brachiocephalic artery, or upstream enough to occlude the coronary arteries, or to pass through the aortic valve into the ventricle.
What is needed is a peripheral or central access catheter configuration that maintains the competence of weakened aortic valves, and does not challenge the competence of healthy aortic valves, during infusion of cardioplegia, and is more resistant than prior apparatus to migration due to pressure gradients within the patient's aorta.
The following patents are hereby incorporated herein in their entirety: U.S. Pat. Nos. 5,383,854, 5,308,320, 5,820,593, 5,879,316, 5,906,588 and 6,165,162 by Safar et al.; filed Sep. 11, 1998, by Safar et al.; U.S. Pat. No. 5,738,649 by John A. Macoviak; U.S. Pat. Nos. 5,827,237, 5,833,671 and 6,059,757 by John A. Macoviak and Michael Ross; and U.S. Pat. No. 6,117,105, by Bresnahan et al.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides an aortic catheter or cannula having a distal flow control member located at or near a distal end of the cannula. The distal flow control member is positioned within the aortic root and is intended to fulfill at least one and preferably all five of the following functions: occluding the aorta at the aortic root, perfusing the coronary arteries with a selected fluid, maintaining the competence of the aortic valve when perfusing the coronary arteries, resisting migration of the distal flow control member or cannula, and providing a bumper for tactile feedback when placing the catheter. Preferably, the distal flow control member may be an inflatable balloon that is inflated using a cardioplegia fluid, and which will occlude the aorta and deliver an effective volume of cardioplegia fluid to the coronary arteries. The distal flow control member may be shaped to conform to the shape of the aortic root and may also be shaped to conform to the cusps of the aortic valve. The material or materials used in the inflatable distal flow control member should have properties that allow an internal pressure within the distal flow control member to be maintained at a sufficient level to occlude the aorta, while also allowing a controlled volume of fluid to seep or otherwise escape from the balloon for perfusing the coronary arteries. Thus, the surface of the balloon may be porous, or have one or more porous regions, or include apertures that allow cardioplegia to seep or flow when a specific pressure is attained, and/or to prevent flow of cardioplegia when the pressure is higher or lower than ideal for coronary perfusion.
The catheter may further include one or more additional flow control members located downstream from the distal flow control member to segment the aorta for selective perfusion to different organ systems within the body. These flow control members may be inflatable balloons or selectively deployable external catheter valves. The catheter may further include one or more anchoring members located downstream from the distal flow control member. The downstream anchoring member may be a larger inflatable balloon or other anchoring structure that provides sufficient force or friction to prevent the catheter from drifting from a selected position within the aorta. Useable flow control members include, but are not limited to, expandable or inflatable members such as inflatable balloons and valves including collapsible/expandable valves of various configurations including retrograde valves, antegrade valves, and various central flow and peripheral flow valves.
A combination of valves and inflatable members may be used as appropriate for a given procedure, thus in some embodiments, the catheter body can include one or more antegrade and retrograde valves, as well as one or more inflatable balloons. Inflatable balloons and collapsible/deployable valves suitable for this application have been previously described in the patents incorporated by reference above and any desirable or practical inflatable balloon or deployable valve may be used. Inflatable balloons typically include an interior chamber that is in fluid communication with an inflation lumen extending within the catheter shaft a location from within the respective flow control member to a location in the proximal portion which is adapted to extend out of the patient.
A first embodiment of the aortic catheter system of the present invention is configured for retrograde deployment via a peripheral artery, such as the femoral artery. The aortic catheter has an elongated catheter shaft having a proximal end and a distal end. A distal flow control member, preferably in the form of an inflatable balloon
Baker Steve
Leary James J.
Robinson Janine
Samson Wilfred J.
Cardeon Corporation
Fulwider Patton Lee & Utecht LLP
Tranh LoAn H.
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