Surgery – Instruments – Internal pressure applicator
Reexamination Certificate
1999-08-03
2001-06-12
Jackson, Gary (Department: 3731)
Surgery
Instruments
Internal pressure applicator
C606S159000
Reexamination Certificate
active
06245087
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to systems and methods useful for deploying medical devices within a body, such as a patient's blood vessel. More specifically, the invention provides a variable diameter expansion frame system for temporary or permanent deployment of medical devices, such as a blood filter, a stent, a manometer, or an occluder, in arteries or veins. The frame can be placed in a collapsed condition to facilitate insertion of the device and in an expanded condition to deploy the medical device. The diameter of the frame can be varied to achieve maximal contact with the vascular wall.
BACKGROUND OF THE INVENTION
Treatment of thrombotic or atherosclerotic lesions in blood vessels using the endovascular approach has recently been proven to be an effective and reliable alternative to surgical intervention in selected patients. For example, directional atherectomy and percutaneous translumenal coronary angioplasty (PTCA) with or without stent deployment are useful in treating patients with coronary occlusion. These endovascular techniques have also proven useful in treating other vascular lesions in, for example, carotid artery stenosis, peripheral arterial occlusive disease (especially the aorta, the iliac artery, and the femoral artery), renal artery stenosis caused by atherosclerosis or fibromuscular disease, superior vena cava syndrome, and occlusion iliac vein thrombosis resistant to thrombolysis.
It is well recognized that one of the complications associated with endovascular techniques is the dislodgment of embolic materials which can occur during manipulation of the vessel, thereby causing occlusion of the narrower vessels downstream and ischemia or infarct of the organ which the vessel supplies. There are a number of devices designed to provide blood filtering for entrapment of vascular emboli in arteries. These devices have also been placed prophylactically, e.g., in the inferior vena cava, for prevention of pulmonary embolism in patients with a propensity for thromboembolism.
Filters mounted to the distal end of guidewires have been proposed for intravascular blood filtration. A majority of these devices includes a filter which is attached to a guidewire and is mechanically actuated via struts or a pre-shaped basket which deploys in the vessel. These filters are typically mesh “parachutes” which are attached to the shaft of the wire at the distal end and to wire struts which extend outward in a radial direction on the proximal end. The radial struts open the proximal end of the filter to the wall of the vessel. Blood flowing through the vessel is forced through the mesh thereby capturing embolic material in the filter.
One of the major disadvantages of present filtering devices is that the maximal expansion diameters of the deployed filters are fixed and sometimes fail to optimally and uniformly engage the vascular wall. An operator can only estimate the diameter of the vessel of interest and choose the filter accordingly. If the vessel, e.g., the aorta, is significantly affected by atherosclosis, the actual luminal diameter of the vessel would be over-estimated. In addition to blood filtering devices, this problem is also recognized for deployment of other medical devices, e.g., stents and occluders.
What is needed are simple and safe devices which facilitate placement of other medical devices in a body cavity, such as arteries and veins, and can be variably adjusted to ensure optimal placement of the medical devices. Existing devices are inadequate for this purpose.
SUMMARY OF THE INVENTION
The present invention provides devices and methods for temporary placement of medical devices, including a filter, an occluder, and a stent in a body cavity. More specifically, the invention provides a expansion frame system, the diameter of which can be variably adjusted to facilitates, for example, insertion of blood filter for capturing embolic material in an artery or vein.
In one embodiment, the expansion frame system includes an outer wire, an inner wire, and a circular or elliptical frame. The outer wire has a lumen communicating with a proximal end and a distal end, and is adapted to receive a percutaneous endovascular medical instrument. The inner wire, having a proximal end and a distal end, is disposed within the lumen of the outer wire. The distal ends of the inner and outer wires are attached, respectively, to the frame at first and second circumferential points at approximately 180° from each other. The proximal ends of the inner and outer wires can be manipulated so that the outer wire can be displaced relative to the inner wire, causing the frame to rotate about an axis perpendicular to the line defined by the first and second circumferential points. In this way, the frame can be placed in a collapsed or an expanded condition.
In another embodiment, the expansion frame system further includes a force biasing element, such as a spring, disposed about the distal end of the inner wire. The distal region of the outer wire has an opening, through which the inner wire passes to attach to the circular or elliptical frame. The biasing element is capable of biasing the second circumferential point of the circular frame away from the opening of the outer wire.
In still another embodiment, the expansion frame system includes a syringe having a barrel and a plunger, where the outer wire is housed within a lumen of the barrel and is mounted on a distal surface of the plunger. The proximal end of the inner wire passes through the distal surface of the plunger and is mounted on the barrel. When the plunger is advanced slideably in the lumen of the barrel, the outer wire is displaced relative to the inner wire, causing the frame to rotate about an axis perpendicular to the line defined by the first and second circumferential points. In other embodiments, the proximal end of the barrel includes a locking mechanism, capable of fixing the displacement of the plunger relative to the barrel.
In certain embodiments, an occluding device, such as a non-permeable membrane, is mounted on the frame. When in use, the membrane provides isolation of blood flow in a vessel, e.g., isolation of aortic blood flow during cardiopulmonary bypass. In other embodiments, a filtering device, e.g., a parachute, basket, or scroll, is mounted on the frame, and a mesh is disposed over the frame. The filtering device may include an inflation seal for achieving better contact with the vascular walls. The construction and use of an associated filter mesh have been thoroughly discussed in earlier applications including Barbut et al., U.S. application Ser. No. 08/533,137, filed Nov. 7, 1995, Barbut et al., U.S. application Ser. No. 08/580,223, filed Dec. 28, 1995, Barbut et al., U.S. application Ser. No. 08/584,759, filed Jan. 9, 1996, Barbut et al., U.S. application Ser. No. 08/640,015, filed Apr. 30 1996, Barbut et al., U.S. application Ser. No. 08/645,762, filed May 14, 1996, and, Barbut et al., U.S. Pat. No. 5,662,671, and the contents of each of these prior applications are expressly incorporated herein by reference.
The methods of the present invention are useful for deploying a medical device within a body cavity for, e.g., protecting a patient from embolization during an endovascular procedure. The expansion frame system can be inserted to capture plaque and/or thrombi from the coronary artery, aorta, common carotid artery, external and internal carotid arteries, brachiocephalic trunk, middle cerebral artery, basilar artery, subclavian artery, brachial artery, axillary artery, iliac artery, renal artery, femoral artery, popliteal artery, celiac artery, superior mesenteric artery, inferior mesenteric artery, anterior tibial artery, posterior tibial artery, and all other arteries carrying oxygenated blood. The expansion frame system can be used prophylactically in patients with hypercoagulable state, including protein C or protein S deficiency, to prevent pulmonary embolism. It can also be used during an endovascular procedure to prevent distal embolization of
Embol-X Inc.
Jackson Gary
Lyon & Lyon LLP
Trinh (Vikki) Hoa
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