Surgery – Instruments – Surgical mesh – connector – clip – clamp or band
Reexamination Certificate
2000-06-16
2004-03-30
Evanisko, George R. (Department: 3762)
Surgery
Instruments
Surgical mesh, connector, clip, clamp or band
Reexamination Certificate
active
06712831
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present relates generally to medical apparatus and methods. More particularly, the present invention relates to methods and apparatus for creating isolated working spaces within the lumen or a blood vessel to facilitate forming end-to-side anastomoses.
Coronary artery bypass graft (CABG) surgery remains one of the most common treatment for coronary artery disease in the United States and other developed countries. Vein grafts, typically harvested from the patient's legs are connected to the aorta and then to the coronary arteries beyond diseased regions. This procedure is typically performed with the patient's heart stopped after initiation of cardiopulmonary bypass. Cardiopulmonary bypass and stopping the heart has been associated with stroke as well as heart muscle damage. To reduce these risks, surgeons have developed techniques to perform CABG while the heart is still beating avoiding cardiopulmonary bypass.
CABG using beating heart technique is performed in the following manner. After obtaining the appropriate level of anesthesia, the surgeon makes an incision over the sternum after which the sternum is divided. The pericardial sac is opened and the patient's aorta and heart are identified and examined. Simultaneously, saphenous veins are harvested from the patient's legs. The surgeon clamps the aorta with a side biting clamp, partially occluding the aorta. A small incision in the aorta is made after which hole punch device is used to make an appropriate size hole, typically 4-6 mm in diameter. The saphenous vein is then sutured onto the aorta. Similarly, the site on the coronary artery where the distal anastomosis will be placed is identified after which an incision is made and the vein sutured.
Clamping the aorta using the side biting technique as well as using cross clamp technique as used during cardiopulmonary bypass, is associated with trauma to the aorta as well as releasing plaque in to the circulation possibly causing a stroke.
In order to at least partially overcome these difficulties, U.S. Pat. No. 5,944,730 proposes to use a device which can create a working space on the interior surface of a blood vessel wall without interrupting the flow of blood through the blood vessel, such as the aorta. The device comprises an inverted cone at the end of a shaft, where the cone can be deployed in the manner of an umbrella. The peripheral lip of the cone is then drawn proximally against the interior wall to isolate the working space from blood flow. The device is useful in stopped heart procedures as well as in beating heart procedures.
Although promising, the device of U.S. Pat. No. 5,944,730, itself suffers from certain limitations. The inverted cone is a rather rigid structure which may have difficulty mating and sealing against the interior surface of the aorta or the blood vessel. Moreover, the relatively rigid nature of the cone can itself disrupt and dislodge plaque from the interior of the aorta, presenting an immediate risk of stroke and peripheral vascular damage since circulation has not been stopped. Additionally, the mechanical structure of the device will require a relatively large profile, making removal of the device after an end-to-side anastomosis has been formed somewhat difficult. In short, the device of U.S. Pat. No. 5,944,730, is complex, cumbersome, and difficult to deploy.
For these reasons, it would be desirable to provide improved and alternative methods and devices for forming working spaces within the aorta and other blood vessels without the need to stop blood flow through the blood vessel. In particular, it would be desirable to create isolated regions or “working spaces” on the aorta wall which are suitable for preparing an anastomotic hole which can subsequently be sutured or otherwise attached to a saphenous vein or other graft. The devices used to form such working spaces should be capable of forming tight seals with the inner wall of the aorta with minimum trauma and risk of emboli release. The devices should have a low profile to facilitate both introduction to the aorta or the blood vessel as well as withdrawal from the blood vessel lumen after the anastomosis has been formed. At least some of these objectives will be met by the inventions described hereinafter.
2. Description of the Background Art
U.S. Pat. No. 5,944,730, describes a device having an inverted shell that is mechanically deployed within a blood vessel lumen to create a working space for performing an end-to-side anastomosis. The device has a relatively large profile and requires an incision for initial placement in the blood vessel. The deployable shell would not be expected for form an optimum seal with the interior blood vessel wall after deployment.
Other devices for locating and/or creating isolated regions within blood vessels for anastomotic attachments are described in EP 894 475 and PCT publications WO 97/47261 and WO 95/17127.
Devices for sealing punctures in blood vessel walls, atrial septums, and the like, are described in U.S. Pat. Nos. 4,744,364; 4,794,928; 5,192,301; 5,222,974; 5,330,446; 5,342,393; 5,350,399; 5,383,896; 5,496,332; 5,593,422; 5,630,833; 5,690,674; 5,700,277; 5,766,220; 5,782,860; 5,922,009; and 5,951,589.
SUMMARY OF THE INVENTION
The present invention provides methods, apparatus, and kits for forming an anastomotic site in the wall of a blood vessel or other body lumen, usually an artery, and more usually the aorta. The anastomotic site will be useful for connection of a graft vessel, typically a portion of the patient's own saphenous vein which is harvested earlier in the procedure. Other conduits which may be harvested include the brachiocephalic vein as well as the radial and internal mammary arteries. In addition to the use of harvested veins, grafts formed from ePTFE, dacron, and the like, may also find use under certain circumstances. Other body lumens where anastomotic sites may be formed using the present invention include the intestines, both small and large.
The working surface formed by the methods of the present invention will be a small volume within the lumen of the blood vessel which is isolated from blood flow which would otherwise pass through that space. The working space will usually be circular or annular in the region where it interfaces with the inner wall of the blood vessel, usually having a diameter in the range from 3 mm to 10 mm, more usually from 4 mm to 6 mm. As described in more detail below, the working space will be defined by an inflatable barrier which typically has a hemispherical or ovoid geometry. The volume of the working space will generally be from 7 mm
3
to 250 mm
3
, usually from 20 mm
3
to 50 mm
3
. Once formed on the inner wall of the blood vessel, the working space will be available for any desired purpose. Usually, the space will be used initially to permit cutting or punching of an anastomotic hole through the blood vessel wall, where the hole will open wholly into the working space. Additionally, after the anastomotic hole is formed, the working space will usually be used to accommodate the needles used to suture a distal end of the graft vessel to the anastomotic hole in the blood vessel wall.
Of particular interest to the present invention, the working space will be formed by an inflatable barrier which has a recessible surface which is positioned or engaged against the inner surface of the blood vessel wall. The inflatable barrier will have a very low profile prior to inflation, typically having an outer diameter below 2 mm, preferably below 1.5 mm. Additionally, after deflation, the inflatable barrier will again have a low profile to facilitate withdrawal from the blood vessel through which the anastomosis is being formed. The recessible surface may be performed as part of the geometry of the inflatable barrier. That is, the recession may form as the barrier is inflated. In such cases, the recession may be concave, annular, or have some other complex shape which accommodates a particular purpose. Alterna
Bajor Jordan T.
Kaplan Aaron V.
Evanisko George R.
Townsend and Townsend / and Crew LLP
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