Surgery – Blood drawn and replaced or treated and returned to body
Reexamination Certificate
2000-02-01
2004-03-09
Sykes, Angela D. (Department: 3762)
Surgery
Blood drawn and replaced or treated and returned to body
C604S006110, C604S006140
Reexamination Certificate
active
06702773
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to medical devices and methods for providing differential perfusion. More particularly, the present invention pertains to novel cardiopulmonary bypass systems and to aortic catheter devices for establishing differential perfusion in a patient where selective hypothermia or hypothermia is desirable.
BACKGROUND OF THE INVENTION
Partial or full cardiopulmonary bypass (hereafter “CPB”) support is needed for medical procedures requiring general anesthesia where lung function is to be arrested during routine and high-risk cardiovascular, cardioneural, neurovascular and other surgical interventions including beating, fully arrested or partially arrested cardiac procedures, to maintain cardiovascular, cardioneural and corporeal support of the respective heart, cerebral and corporeal organ systems. Such surgical interventions include treatment of aneurysms, congenital valve disease, and coronary artery disease.
In procedures where the heart is to be fully or partially arrested, it has been conventionally preferred that the heart and coronary vasculature be isolated from the rest of the cardiovascular system by application of an external cross clamp or side biting clamp. Isolation allows antegrade or retrograde perfusion of cold, warm ornormothermic oxygenated blood cardioplegia or crystalloid cardioplegia to the coronary arteries to aid in the preservation of the myocardium and to prevent dispersion of cardioplegia to the rest of the body. The heart chambers may then be vented for decompression and to create a bloodless surgical field for intracardiac interventions. For rapid cooling and arrest of the myocardium in open-chest procedures, direct application of a topical ice slush or cold pericardial lavage into the thoracic space is performed simultaneously while the cold coronary perfusion process is being accomplished.
One preferred way to accomplish CPB is to insert a venous cannula into the venous system, to withdraw deoxygenated blood into an extra corporeal circuit. A pump circulates the withdrawn blood through a blood oxygenator, heat exchanger and filter apparatus. The blood is then delivered to an aortic perfusion catheter that is inserted in the aorta of a patient.
Although CPB has been a valuable technology enabling surgical interventions, stroke and neurological deficit have been a well documented sequel as associated with the above described procedure. Recent literature has documented that the incidence of stroke is as high as 6.1% with an additional 30-79% of patients suffering from some form of cognitive deficit. Neurological deficit varies from patient to patient, however common injuries include: loss of memory, concentration and hand-eye coordination, and an increase in morbidity and mortality. The impact on the patient is significant, but factors such as age, the level of intellectual activity and the amount of physical activity pursued by the patient prior to surgery all affect the quality of life. Finally, patients who suffer from neurologic injury have a substantially prolonged hospital stay, with an attendant increase in cost (Neurological Effects of Cardiopulmonary Bypass; Rogers AT, Cardiopulmonary Bypass Principles and Practice; Gravlee GP, 21:542).
One of the likely causes of stroke and neurological deficit is the release of emboli into the blood stream during heart surgery. Potential embolic materials include atherosclerotic plaques or calcific plaques from within the aorta or cardiac valves and thrombus or clots from within the chambers of the heart. These potential emboli may be dislodged during surgical manipulation of the heart and the ascending aorta or due to high velocity jetting (sometimes called the “sandblasting effect”) from the aortic perfusion cannula. In addition, application and release of an external cross clamp or side biting clamp has been shown to release emboli into the blood circulation. Other potential sources of emboli include any contact of the vessel walls with medical devices that have been introduced into the aorta. Additional sources of emboli include gaseous micro emboli formed when using a bubble oxygenator for CPB and “surgical air” that enters the heart chambers or the blood stream during surgery through open incisions or through the aortic perfusion cannula.
In an effort to reduce the deleterious effects of CPB and median sternotomies there has been much development in the area of minimally invasive cardiac surgery (MICS) to avoid the complications of CPB and the use of balloon catheters to address the clinical problems associated with a conventional median sternotomy and the attendant use of a cross clamp to occlude the ascending aorta. 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 a 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. Nonetheless, the deployment of balloons within the aorta may cause substantial forces to come to bear on the surrounding vessel and any shifting of such balloon may further increase the risk of dislodging embolic materials.
In clinical use, these single balloon catheters have shown a tendency to migrate in the direction of the pressure gradient within the aorta. More specifically, during infusion of cardioplegia, the balloon catheter will tend to migrate downstream due to the higher pressure on the upstream side of the balloon and, when the CPB pump is on, the balloon catheter will tend to migrate upstream into the aortic root due to the higher pressure on the downstream side of the balloon. This migration can be problematic if the balloon migrates far enough to occlude the brachiocephalic artery on the downstream side or the coronary arteries on the upstream side.
Another important development in the area of aortic balloon catheters is the concept of selective aortic perfusion. Described in commonly owned U.S. Pat. Nos. 5,308,320, 5,383,854 and 5,820,593 to Safar et al. is a method and apparatus for selective perfusion of different organ systems within the body. Other U.S. patents which address the concept of selective aortic perfusion include; U.S. Pat. No. 5,738,649, by Macoviak, U.S. Pat. Nos. 5,827,237 and 5,833,671 by Macoviak et al.; and commonly owned, copending U.S. patent application Ser. No. 08/665,635, filed Jun. 18, 1996, by Macoviak et al. All the above listed patents and patent applications, as well as all other patents referred to herein, are hereby incorporated by reference in their entirety.
Disadvantages associated with heretofore known devices and methods for establishing differential perfusion include the difficulty inherent in deploying numerous, complex devices in the vasculature, maintaining such devices in position during the procedure, avoiding the dislodgment of embolic materials and possibly the need to take steps necessary to recapture any such materials downstream. An improved device and method is needed that simplifies the deployment procedure and the efforts needed to maintain the device or devices in position while greatly reducing if not substantially obviating the risk of dislodging embolic materials. Although the foregoing discussion is primarily focused on stopped heart procedures, the present invention also has applicability in beating heart procedures including cardiac surgery and stroke.
SUMMARY OF THE INVENTION
In keeping with the foregoing discussion,
Esch Brady
Lee Mike
Macoviak John
Samson Wilfred J.
Cardeon Corporation
Deak Leslie
Fulwider Patton Lee & Utecht LLP
Sykes Angela D.
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