Surgery – Instruments – Blood vessel – duct or teat cutter – scrapper or abrader
Reexamination Certificate
2001-03-30
2003-11-25
Truong, Kevin T. (Department: 3731)
Surgery
Instruments
Blood vessel, duct or teat cutter, scrapper or abrader
Reexamination Certificate
active
06652548
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to medical devices and methods. In one embodiment, the present invention relates to devices and methods for disrupting, collecting, and removing thrombus from blood vessels and other body lumens.
Thrombosis and atherosclerosis are common ailments which occur in humans and which result from the deposition of thrombus and clot on the walls of blood vessels. When hardened, such deposits are commonly referred to as plaque. Such deposits are most common in the peripheral blood vessels that feed the limbs of the human body and the coronary arteries which feed the heart. Stasis, incompetent valves, and trauma in the venous circulation cause thrombosis, particularly occurring as a deep vein thrombosis in the peripheral vasculature. When such deposits build-up in localized regions of the blood vessel, they can restrict blood flow and cause a serious health risk.
In addition to forming in the natural vasculature, thrombosis is a serious problem in “artificial” blood vessels, particularly in peripheral femoral-popliteal and coronary bypass grafts and dialysis access grafts and fistulas. The creation of such artificial blood vessels generally involves anastomotic attachment at at least one, and usually at at least two, locations in the vasculature. Such sites of an anastomotic attachment are particularly susceptible to thrombus formation due to narrowing caused by intimal hyperplasia, and thrombus formation at these sites is a frequent cause of failure of the implanted graft or fistula. The arteriovenous grafts and fistulas which are used for dialysis access are significantly compromised by thrombosis at the sites of anastomotic attachment and elsewhere. Thrombosis often occurs to such an extent that the graft needs to be replaced within a few years or, in the worst cases, a few months.
A variety of methods have been developed for treating thrombosis and atherosclerosis in the coronary and peripheral vasculature as well as in implanted grafts and fistulas. Such techniques include surgical procedures, such as coronary artery bypass grafting, and minimally invasive procedures, such as angioplasty, atherectomy, transmyocardial revasculaturization, and the like. In many of the surgical clinical approaches to removing unwanted material, the treatment site is accessed directly through a surgical incision. Of particular interest of the present invention, a variety of techniques generally described as “thrombectomy” have been developed. Thrombectomy generally refers to procedures for the removal of relatively soft thrombus and clot from the vasculature. Removal is usually achieved by mechanically disrupting the clot, optionally with the introduction of thrombolytic agents. The disrupted thrombus or clot is then withdrawn through a catheter, typically with a vacuum or mechanical transport device.
Thrombectomy generally differs from angioplasty and atherectomy in the type of occlusive material which is being treated and in the desire to avoid damage to the blood vessel wall. The material removed in most thrombectomy procedures is relatively soft, such as the clot formed in deep vein thrombosis, and is usually not hardened plaque of the type treated by angioplasty in the coronary vasculature. Moreover, it is usually an objective of thrombectomy procedures to have minimum or no deleterious interaction with the blood vessel wall. Ideally, the clot will be disrupted and pulled away from the blood vessel wall with no harmful effect on the wall itself.
While successful thrombectomy procedures have been achieved, most have required comprise between complete removal of the thrombosis and minimum injury to the blood vessel wall. While more aggressive thrombectomy procedures employing rotating blades can be very effective at thrombus removal, they can present a significant risk of injury to the blood vessel wall. Alternatively, those which rely primarily on vacuum extraction together with minimum disruption of the thrombus, often fail to achieve sufficient thrombus removal.
In work related to the present invention, an expansible macerator for safely breaking up or disrupting thrombus and other occlusive materials has been proposed. U.S. patent application Ser. No. 09/454,517 filed on Dec. 6, 1999 and entitled “Systems and Methods for Clot Disruption and Retrieval,” describes a catheter having an expansible positioning cage and a helical macerator positioned within the cage. The macerator can be separated from the surrounding cage so as to maintain separation between the macerator and a surrounding wall of the body lumen. This caged macerator represents a significant advancement in the art, as it allows disruption of soft clot while inhibiting trauma to blood vessels of varying diameters. However, as with all advances, still further improvements would be desirable. In particular, it may be beneficial to provide more aggressive and more rapid removal of clot material. It would also be helpful to allow the physician to selectively and controllably remove plaque or other more solid occlusive material during a thrombectomy, preferably using the thrombectomy catheter. It may also be beneficial to more uniformly urge the severed debris toward an aspiration port of the thrombectomy catheter.
In light of the above, it would be beneficial to provide improved devices, systems, methods, methods for manufacture, and kits for removing thrombus material from the vasculature and other body lumens. It would be particularly desirable to provide improved techniques for advancing a guidewire or guide catheter, positioning a treatment catheter across the blocking occlusion, isolating the treatment site, and further treating the occlusion while minimizing or eliminating any distal emboli. An improved procedure would also benefit from having a device that can rapidly aspirate the occlusive material from the body lumen. Optionally, these improved devices and methods might be used to treat a total occlusion as the treatment device is being advanced through the occlusion, facilitating placement of a wire across the occlusion so that further treatment can be easily commenced. Device and methods which allow creation of a channel through a total occlusion for placement of a guidewire would also be advantageous, as would improved debulking of stenotic tissues.
Some or all of these objectives may be met by the device and methods of the present invention.
2. Description of the Background Art
As mentioned above, systems and methods for clot disruption and removal related to the present invention are described in U.S. patent application Ser. No. 09/454,517. A related mechanical pump for removal of fragmented matter and methods was described in U.S. patent application Ser. No. 09/590915, filed on Jun. 9, 2000. A further related method and system for reinfusing filtered body aspirates is described in U.S. Provisional Patent No. 60/174,108, filed on Dec. 31, 1999.
A cutting stent with a flexible tissue extractor is described in U.S. Pat. No. 6,036,708. A compressible/expandable atherectomy cutter is described in U.S. Pat. No. 5,224,945. Unitary removal of plaque is described in U.S. Pat. No. 5,665,098. A method for performing a partial atherectomy is described in U.S. Pat. No. 5,282,484, while an atherectomy device having a helical blade and a blade guide is described in U.S. Pat. No. 5,569,277. A catheter arthrotome is described in U.S. Pat. No. 5,178,625. A surgical apparatus for transurethral resection is described in U.S. Pat. No. 3,320,957. A vessel deposit sharing apparatus is described in U.S. Pat. No. 5,527,326.
A coiled stent with locking ends is described in U.S. Pat. No. 5,725,549. A medical instrument with a slotted memory metal tube is described in U.S. Pat. No. 5,885,258. A method for manufacturing a tubular medical device is described in U.S. Pat. No. 6,027,863. The following U.S. Patent Nos. may also be relevant: U.S. Pat. Nos. 6,010,449; 5,968,064; 5,741,270; 5,766,191; 5,569,275; 5,501,694; 5,795,322; 5,904,968; 5,224,945; 5,312,425;
Demarais Denise M.
Evans Michael A.
Eversull Christian S.
Leeflang Stephen A.
Bacchus Vascular Inc.
Barrish, Esq. Mark D.
Bui Vy Q.
Townsend & Townsend & Crew LLP
Truong Kevin T.
LandOfFree
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