Surgery – Instruments – Cutting – puncturing or piercing
Reexamination Certificate
2000-02-25
2001-06-26
Dawson, Glenn K. (Department: 3761)
Surgery
Instruments
Cutting, puncturing or piercing
C606S185000, C604S035000, C128S898000, C600S566000
Reexamination Certificate
active
06251121
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to apparatus and methods for forming a transmural channel in a hollow-body organ, such as the heart. More particularly, the present invention provides a device that enables a clinician to perform transmyocardial revascularization by mechanically boring channels through the myocardium.
BACKGROUND OF THE INVENTION
A leading cause of death in the U.S. and the world today is coronary artery disease, in which atherosclerotic plaque causes blockages in the coronary arteries, resulting in ischemia of the heart (i.e., inadequate blood flow to the myocardium). The disease manifests itself as chest pain or angina. In 1996, approximately 7 million people suffered from angina in the U.S.
Coronary artery bypass grafting (CABG), in which the patient's chest is surgically opened and an obstructed artery replaced with a native artery harvested elsewhere or a synthetic graft, has been the conventional treatment for coronary artery disease for the last thirty conventional treatment for coronary artery disease for the last thirty years. Such surgery creates significant trauma to the patient, requires long recuperation times, and poses serious risks of mortality. In addition, experience has shown that the bypass vessel or graft becomes obstructed with time, requiring further surgery.
More recently, catheter-based therapies such as percutaneous transluminal coronary angioplasty (PTCA) and atherectomy have been developed. In PTCA, a mechanical dilatation device is disposed across an obstruction in the patient's artery and then dilated to compress the plaque lining the artery to restore patency to the vessel. Atherectomy involves using an end effector, such as a mechanical cutting device (or a laser) to cut (or ablate) a passage through the blockage. Such methods have drawbacks, however, ranging from re-blockage of vessels dilated by angioplasty to catastrophic rupture or dissection of the vessel during atherectomy. Moreover, these methods may only be used for that fraction of the patient population where the blockages are few and are easily accessible. Neither technique is suitable for the treatment of diffuse atherosclerosis.
A more recent technique that holds promise of treating a larger percentage of the patient population, including those patients suffering from diffuse atherosclerosis, is referred to as transmyocardial revascularization (TMR). In this method, a series of channels are formed in the left ventricular wall of the heart. These channels may be transmural (i.e., from the epicardium to the endocardium), or only partial (for example, from the endocardium and terminating in the myocardium).
Typically, between 15 and 40 channels about 1 mm in diameter and up to 3.0 cm deep are formed with a laser in the wall of the left ventricle to perfuse the heart muscle with blood coming directly from the inside of the left ventricle, rather than from the coronary arteries. It has also been proposed that the formation of such channels stimulates the creation of small blood vessels within the myocardium. Apparatus and methods have been proposed to create these channels both percutaneously and intraoperatively,(i.e., with the chest opened).
U.S. Pat. Nos. 5,380,316 and 5,554,152 to Aita et al. describe intraoperative laser apparatus for forming channels extending from the epicardium to the endocardium. The laser includes an optical wave guide that is held against the patient's heart. Several pulses of the laser are required to form a transmural channel by ablation. U.S. Pat. No. 5,389,096 to Aita et al. describes a catheter-based laser system for performing TMR percutaneously, i.e., from within the left ventricle. U.S. Pat. No. 4,658,817 to Hardy describes a laser-based system for intraoperatively performing TMR that includes a needle portion for perforating an outer portion of the tissue, and a laser for ablating the inner portion.
U.S. Pat. No. 5,591,159 to Taheri describes a mechanical catheter-based apparatus for performing TMR involving a catheter having an end effector formed from a plurality of spring-loaded needles. The catheter first is positioned percutaneously within the left ventricle. A plunger is released so that the needles are thrust into the endocardium. The needles are then withdrawn, forming small channels that extend into the myocardium. The patent suggests that the needles may be withdrawn and advanced repeatedly at different locations under fluoroscopic guidance. The patent does not appear to address how tissue is ejected from the needles between the tissue-cutting steps.
The disadvantages of the above-described previously known methods and apparatus for performing TMR are numerous and will impede the acceptance of this new treatment method. For example, laser-based systems, such as described in the Aita et al. patents, require costly and sophisticated laser technology. In addition, the laser apparatus may not provide the clinician sufficient tactile sensation to judge when the endocardium has been punctured, thus creating the risk that laser pulses may be inadvertently directed against other tissue within the left ventricle before the laser is discontinued. Laser-based devices also rely on the clinician to hold the laser element steadily against the beating heart. Moreover, laser-based systems do not provide for removal of ablated tissue, thus causing a risk of embolization by ablated tissue.
Likewise, previously known mechanical systems such as described in the Taheri patent do not address issues such as rebounding of the needle away from the ventricle wall during deployment or how to remove tissue cores from the needles, and again rely on fluoroscopy to determine the location of the distal tip of the device within the heart.
In view of the shortcomings of previously known TMR devices, it would be desirable to provide apparatus and methods for intraoperatively performing surgery, such as TMR, using less costly and more readily available components.
It also would be desirable to provide apparatus and methods for performing TMR that provide the capability to precisely monitor and control the channel forming process, without a risk of inadvertently damaging other tissues within the left ventricle.
It would be desirable to provide apparatus and methods of performing TMR that stabilize an end region of the apparatus against a beating heart.
It further would be desirable to provide apparatus and methods for performing TMR that enable the tissue removed during the channel-forming process to be aspirated, thereby lessening the potential for embolization.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of this invention to provide apparatus and methods for intraoperatively performing surgery, such as TMR, using less costly and more readily available components.
It is another object of this invention to provide apparatus and methods for performing TMR that provide the capability to precisely monitor and control the channel forming process, without a risk of inadvertently damaging other tissues within the left ventricle.
It is a further object of the present invention to provide apparatus and methods of performing TMR that stabilize an end region of the apparatus against a beating heart.
It is also an object of the present invention to provide apparatus and methods for performing TMR that enable the tissue removed during the channel-forming process to be aspirated, thereby lessening the potential for embolization.
These and other objects of the present invention are accomplished by providing apparatus and methods for intraoperatively performing TMR with a device including an end region having a mechanical cutting head for forming transmural channels and means for stabilizing the end region in contact with the beating heart. The cutting head is adapted to cooperate with a source of suction to evacuate tissue severed during the channel-forming process, and may optionally include an electrode for cauterizing the tissue surrounding the channel.
In one preferred embodiment of the apparatus of the present inv
AngioTrax, Inc.
Dawson Glenn K.
Fish & Neave
Pisano Nicola A.
LandOfFree
Apparatus and methods for intraoperatively performing surgery does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and methods for intraoperatively performing surgery, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and methods for intraoperatively performing surgery will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2455058