Surgery – Blood drawn and replaced or treated and returned to body
Reexamination Certificate
2004-01-16
2004-11-23
Doerrler, William C. (Department: 3744)
Surgery
Blood drawn and replaced or treated and returned to body
C604S096010, C604S503000
Reexamination Certificate
active
06821263
ABSTRACT:
FIELD OF THE INVENTION
The field of this invention is cardiac bypass surgery and cardiopulmonary bypass.
BACKGROUND OF THE INVENTION
During cardiac surgery for procedures such as coronary artery bypass grafting, heart valve repair or replacement, septal defect repair, pulmonary thrombectomy, atherectomy, aneurysm repair, aortic dissection repair and correction of congenital defects, cardiopulmonary bypass and cold cardiac ischemic arrest are often required. Typically, a cooled cardioplegia solution, a solution containing elevated levels of potassium, for example, is administered in the antegrade direction (in the direction of normal blood flow) through the patient's aorta and into the coronary arteries. The cold (2 to 3 degrees centigrade) cardioplegia solution stops the heart from beating and reduces its temperature to minimize damage to the heart during surgery. The cardioplegia solution exits the coronary circulation through the coronary veins at the coronary sinus, where it empties into the right atrium. Cardiopulmonary bypass maintains the peripheral circulation of oxygenated blood to all body organs except the heart during the period of cold, cardioplegic, ischemic arrest.
For some patients, such as those suffering from critical coronary artery stenosis and aortic valve disease, antegrade perfusion may be difficult, inefficient and incomplete. Retrograde (in the direction opposite of normal blood flow) cardioplegia, using current technology, may be administered via the coronary sinus into the coronary circulation using devices, which cannulate the coronary sinus. Such cannulation of the coronary sinus by prior art devices requires inserting a catheter into the coronary sinus and perfusing cardioplegia into the sinus. Drainage of cardioplegia solution is accomplished into the coronary ostea located at the base of the aorta. The problem with prior art methods is that either the right or left heart will be perfused, but not both, since the right coronary veins come off the coronary sinus at an angle and are not cannulated by current catheters that cannulate the left coronary veins. Thus, incomplete perfusion of segments of the heart muscle, primarily the right heart and septum, will occur since the right coronary veins frequently come off near the coronary sinus ostea or within the right atrial wall proper. The right coronary veins are not perfused by prior art retrograde cardioplegic catheters.
Currently surgeons performing cardiac bypass surgery use one or more cannulae for venous drainage and an additional cannula for retrograde perfusion. The multiple cannulae are obstacles and restrict visibility in the surgical arena. Placement of the cardioplegia cannula into the coronary sinus is a semi-blind procedure performed through an additional purse-string suture-closed access port via the right atrium. The retrograde cannula may be improperly positioned within the coronary sinus, which results in critical coronary vessels being inadequately perfused. Typically, placement of currently available retrograde cardioplegia cannula within the coronary sinus results in retrograde perfusion of the left heart but inadequate retrograde perfusion of the right heart because of cannula obstruction of the right coronary ostea as they arise from the coronary sinus. Thus the tissue of the left heart is perfused, in a retrograde direction, with cardioplegia solution but the right heart is perfused with a diminished, or no, supply of cardioplegia solution since the right coronary veins are generally a side-branch of the left coronary veins at the coronary sinus and the right coronary veins are blocked by the cannula. Poor right heart retrograde perfusion occurs because, most-frequently, anatomic variations of the right coronary sinus and veins cannot be properly perfused with the currently available cannula.
New devices and methods are needed, which facilitate cold cardioplegic arrest, yet limit the number of cannulae required to isolate the heart and coronary blood vessels from the peripheral vasculature, arrest the heart, protect all the coronary blood vessels, protect all or most of the myocardium, and drain venous blood from the inferior and superior vena cava. Furthermore, it would be advantageous to the diseased myocardium being subjected to ischemic arrest if a retrograde cardioplegia perfusion cannula could perfuse the coronary vasculature of both the right and left heart simultaneously.
SUMMARY OF THE INVENTION
This invention relates to a balloon, or tourniqueted, catheter or cannula useful in the retrograde administration of cardioplegia through the coronary sinus and simultaneous venous drainage during cardiac bypass surgery without the need to cannulate the coronary sinus.
The invention is a cannula for performing venous drainage and retrograde perfusion of the heart during cardiac bypass surgery. A single multi-lumen cannula of the present invention can perform the same function as multiple cannulae currently used. The cannula of the invention for cardioplegic administration can improve the protection of a heart during periods of ischemia such as occurs during open-heart surgery. The cannula is preferably fabricated from materials, which are biocompatible for the intended use.
One embodiment of the invention is a multi-lumen cannula with occlusive structures for the superior and inferior vena cava, a protection structure, cardioplegia infusion channel, a pressure monitoring port, and venous drainage ports. Occlusion structures may include devices such as, but not limited to, balloons, umbrellas, structures that draw a vacuum against a wall of the heart, externally applied tourniquets, umbrellas with rim-seal balloons, or the like. In a preferred embodiment, the occlusion structures are balloons constructed of elastomeric materials or vacuum-assisted walled structures.
In one embodiment, a first lumen of the cannula is connected to the cardioplegia infusion system and provides cardioplegia solution to arrest the heart. A second cannula lumen is connected to the venous drainage system. The drainage ports are located in the second lumen. A third lumen is connected to the balloon inflation system, which provides inflation fluids, such as water, isotonic saline or cardioplegia solution, under controlled pressure or volume to inflate the occlusion balloons. The pressure of the occlusion balloons and right atrium may also be monitored through additional lumens. The occlusion balloons isolate the heart from the peripheral vasculature by occluding the inferior and superior vena cava just proximal to the right atrium. The inferior and superior vena cava balloons utilized to direct flow into the extracorporeal circuit are optionally movable to accommodate anatomic variability. Additional lumens may be utilized for inflation of multiple balloons, pressure monitoring, flow monitoring, drainage of cardioplegia, fluid and drug infusion and the like. Since it is useful to measure cardioplegic perfusion pressure, a pressure transducer or pressure measuring lumen may, for example, be provided at or near the distal end of the cardioplegia perfusion lumen for this purpose.
The cannula may be placed into the vena cava, for example, via a route through the internal jugular vein, cranial vena cava, femoral vein, or brachial vein. A smaller diameter cannula may be placed through any of the smaller venous access ports. The use of smaller venous access ports may be enabled by use of a pump or vacuum powered venous drainage system, typically external to the cannula. In one embodiment, the catheter or cannula combines the functions of several catheters currently used in cardiac surgery. A single catheter, rather than multiple catheters, facilitates the surgery and improves the surgical field because extra cannulae do not obstruct the operative field. In addition, the number of individual catheters is reduced, providing a more cost effective method for cardiac surgery. Most importantly, improved cardiac protection is achieved compared to that of standard retrograde perfusion cannulae.
In yet another emb
Breznock Eugene M.
Lenker Jay A.
Doerrler William C.
Zec Filip
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