Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1998-04-21
2001-02-20
Kennedy, Sharon (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S096010, C604S523000
Reexamination Certificate
active
06190357
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to devices for the occlusion of blood vessels, more particularly to the occlusion and subsequent perfusion, cardioplegia or venting of blood vessels using a cannula endovascularly inserted within the lumen of the vessel. The system is well suited for occlusion and perfusion of the aortic arch or major arteries during cardiopulmonary bypass procedures.
BACKGROUND OF THE INVENTION
Cardiac surgery often requires that the heart be stilled during the procedure. An arrested heart allows the surgeon sufficient time and a stable environment on which to operate, a particular necessity for lengthy and invasive procedures such as valve replacement. A number of devices and procedures have been developed to enable a physician to stop the heart long enough for a surgical procedure to be performed, and then restart the heart at the termination of the procedure.
Stopped heart procedures are complex and often cause patient trauma during the procedure and during post-operative recovery. Over the years, the application and effectiveness of stopped heart procedures have increased, meanwhile attempts have been made to limit patient trauma recovery time, and overall expense.
To maintain the flow of oxygenated blood during a stopped heart procedure, the heart and lungs must be bypassed during the time that the heart is stopped. This by pass us achieved using a cardiopulmonary bypass (CPB) apparatus. The essential goals of CPB for heart surgery are to provide life-support functions, a motionless, decompressed heart, and a dry, bloodless field of view for the surgeon. In a basic CPB system, the heart is stopped by the infusion of cardioplegia. Oxygen-poor blood is drained by gravity or suctioned from the patient's venous circulation, and is transported to a pump-oxygenator, commonly known as the heart-lung machine, where the blood is exposed to a gaseous mixture that eliminates carbon dioxide and adds oxygen. The venous drainage process may involve placement of a cannula (or cannulae) into the right side of the heart (typically the right atrium), or directly in the major veins (typically the superior vena cava (SVC) and/or inferior vena cava (IVC) or through peripheral vein access sites. An arterial or aortic perfusion cannula is placed in the aorta or another large peripheral artery, such as the common femoral artery, to return oxygenated blood to the patient.
Cardioplegic arrest and CPB are commonly employed during cardiac surgery for treating coronary artery disease and heart valve disease. In coronary artery disease, a buildup of stenotic plaque in the coronary arteries causes the artery to narrow or become occluded. The interruption of the blood flow to the heart causes myocardial infarction, commonly known as a heart attack. Heart valve disease includes two major categories, namely valvular stenosis, which is an obstruction to forward blood flow through the heart valve, and regurgitation, which is the retrograde leakage of blood through the heart valve. Most commonly, valvular stenosis occurs in the aortic valve while regurgitation is typically a congenital condition affecting the mitral valve.
Typically, after the patient's chest has been opened through either a thoracotomy or a stemotomy, a cannula will be inserted into the patient's aortic arch. The insertion of the arterial (aortic) perfusion cannula is usually performed in the following fashion. After the patient's chest has been opened and the pericardium (the protective sac around the heart) has been entered, two concentric purse string sutures are placed into the anterior wall of the ascending aorta just proximal to upstream side of the brachiocephalic trunk. A “choker” tube or sleeve is positioned over the trailing ends of the suture threads to act as a tourniquet for tightening the purse string suture. A small incision is then made through the wall of the aorta in the center of the purse-string sutures. The aortic perfusion cannula is then quickly inserted through that incision into the aorta, taking care to minimize the escape of blood from the puncture site. The purse string sutures are then tightened by means of their respective tourniquets to seal the aortic wall around the perfusion cannula in order to prevent the escape of blood from the aorta. Air is then purged by arterial pressure from the perfusion cannula which is in fluid communication with the pump-oxygenator. A cross-clamp is placed on the aorta just downstream of the aortic root and upstream of the cannula to ensure that no blood flows back toward the aortic valve during CPB.
After CPB has been established, cardioplegia is administered by delivering a cardioplegic solution, such as potassium, magnesium, procaine, or a hypocalcemic solution, to the myocardium by one or a combination of two general techniques, antegrade and retrograde perfusion. Antegrade perfusion of cardioplegia involves the infusion of fluid through the coronary arteries in the normal direction of blood flow. A cannula is typically inserted into the aorta upstream of the aortic clamp and the solution is injected into the aortic root and delivered under pressure in the normal direction of blood flow into the coronary ostia and from there to the myocardium. For procedures on the aortic valve, cardioplegia is typically administered via a transverse aortotomy whereby direct access to the coronary ostia is possible. The cardioplegia is delivered using a wand inserted intermittently into the ostia during the procedure. Retrograde perfusion is accomplished by inserting an occlusion into the coronary sinus and administering cardioplegia upstream of the occlusion and forcing the fluid against the normal flow of the blood into the coronary veins to the myocardial capillary beds.
Once the beating of the heart has been arrested, the surgeon will perform the necessary coronary procedures and repairs. When these repairs have been completed, the arterial and venous cannula will be removed from the surgical area and the entrance sutures tightened to seal the vessel punctures.
The placement of the occluder in the ascending aorta is a particularly delicate operation as the operator must take care so as to not block the left subclavian artery, the brachiocephalic artery, or the left carotid artery, but must instead occlude the aorta just upstream of these aortic branches. Even if the placement of the occluder is proper at the initiation of the coronary repair procedure, the position of the device should be monitored closely to avoid even slight movement as the procedure continues. Movement of the device may result in partial or total closure of the aortic branches, depriving the upper body and brain of the patient of blood during the procedure. Similarly, movement toward the aortic valve and/or the left ventricle of the patient should be avoided to prevent damaging the valve. It would thus be desirable to have a system which could allow imaging of the interior of the vessel to determine proper placement of the cannula within the vessel and to enable imaging of the interior of the vessel intermittently during a procedure.
The design of an endovascularly inserted cannulae must take into account the limited space available in the body passageways used for access to the heart and other regions of interest. The use of multiple cannulae increases the number of percutaneous or direct cut-down procedures required for the procedure and increases the risk or infection and other post-operative complications. Multiple insertions also increase the risk of damage to the internal vasculature and increase the complication and time expenditure for the procedure. It would be most desirable to provide a system which would combine a multitude of functions in one device so that the need for multiple or duplicative devices can be avoided.
The device should have a minimal small cross-sectional diameter to reduce the risk of patient trauma. Particularly with patients having advanced heart disease, scaling and calcium deposits are common on the interior of the femoral and iliac ar
Ferrari Richard M.
Glines Robert C.
Morejohn Dwight P.
Sepetka Ivan
Cardiothoracic Systems, Inc.
Kennedy Sharon
Limbach & Limbach LLP
Rodriguez Cris L.
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