Method and apparatus for treating critical limb ischemia

Abstract

A system and method for treating critical limb ischemia (CLI) including a radiopaque micro stent disposed for cross ankle stenting as well as retrograde pedal/tibial artery access, in conjunction with antegrade access for the recanalization of impaired tibial vessels. A radiopaque medical device is constructed from a tubular-shaped body having a thin wall defining a specific strut pattern. In an additional aspect, the present apparatus introduces a new radiopaque medical device, such as a stent, wherein the tubular body includes a super elastic, nickel-titanium (nitinol) alloy.

Claims

1. A method of treating critical limb ischemia (CLI) comprising the steps of: utilizing a self-expanding radiopaque stent constructed from a tubular-shaped body having a wall defining a specific strut pattern and configured for usage in procedures below the knee and the ankle strap area, wherein the self-expanding radiopaque stent is configured to expand across the ankle joint from above the ankle to below the ankle; utilizing a below-the-knee revascularization method to a body of a patient; entering the body with the self-expanding radiopaque stent through a pedal access point below the knee or at the ankle; delivering the self-expanding radiopaque stent from the lateral plantar to the distal posterior tibial; utilizing an ultrasound machine to assist in the delivery of the self-expanding radiopaque stent; utilizing a continuous medical X-ray image to provide real-time monitoring of the positioning of the self-expanding radiopaque stent; delivering and seating the self-expanding radiopaque stent via an image from the ultrasound machine; unblocking tibial artery occlusions; reutilizing the pedal access point below the knee or at the ankle; and proceeding antegrade around the ankle or retrograde in below-the-knee area to reach lesions and occlusions on an opposing side of the pedal access point.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Advantages of the present invention and better understanding will be apparent from the following detailed description of exemplary embodiments thereof, which description should be considered in conjunction with the accompanying drawings, in which:

(2) FIG. 1 is a simple cross-sectional view shown lengthwise of a braided non-woven micro stent in accordance with one embodiment of the present system.

(3) FIG. 2 is a cross-sectional view of an individual strand of the braided non-woven micro stent.

(4) FIGS. 3A-3B shows the micro stent into the Left Popliteal sheath and detected under ultrasound.

(5) FIG. 4 illustrates a flow diagram for treating critical limb ischemia utilizing the micro stent for insertion below the knee or through the ankle.

DETAILED DESCRIPTION OF THE SEVERAL EMBODIMENTS

(6) Embodiments of the present series of apparatuses, systems and interrelated methods pertain to a coil-reinforced stent use during angioplasty procedures. Throughout the description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. In other instances, well-known structures and devices are shown in generic form to avoid obscuring the underlying principles of the present invention.

(7) FIG. 1 illustrates a cross-section view of one embodiment of a braided non-woven micro stent 10, wherein the micro stent 10 is preferably comprises of forty-eight (48) individual strands arranged in a braided configuration for use in a patient during a medical procedure. In the embodiment shown, the micro stent 10 possesses a length 12 and an outer diameter 14 that defines the overall size of the micro stent 10. Each individual strand 16 of the micro stent 10 is preferably comprised of an outer layer 18 and an inner layer 20 (see FIG. 2).

(8) The actual dimensions of the micro stent 10 may vary depending on the specific medical procedure and/or patient, however the micro stent 10 may be configured as follows:

(9) TABLE-US-00001 Labeled Size Outer Diameter Length 3.0 mm × 40 mm 3.4 mm 40 mm 3.0 mm × 60 mm 3.4 mm 60 mm 3.5 mm × 40 mm 4.0 mm 40 mm 3.5 mm × 60 mm 4.0 mm 60 mm 4.0 mm × 40 mm 4.6 mm 40 mm 4.0 mm × 60 mm 4.6 mm 60 mm 4.5 mm × 40 mm 5.2 mm 40 mm 4.5 mm × 60 mm 5.2 mm 60 mm

(10) FIG. 2 illustrates a cross-sectional view of an individual strand 16 of the micro stent 10 comprising an outer layer 18 and an inner layer 20. In one embodiment, the outer layer 18 is comprised of platinum and the inner layer 20 is comprised of nitinol.

(11) FIGS. 3A-3B illustrates various depictions of the micro stent 10 being deployed and detected via ultrasound. FIG. 4 illustrates a flow diagram for treating critical limb ischemia utilizing the micro stent for insertion below the knee or through the ankle.

(12) FIG. 4 illustrates a method for treating critical limb ischemia utilizing the micro stent 10, wherein at step 100, a radiopaque micro stent is utilized. Next at step 110, utilizing below-the-knee revascularization method by entering the body of the patient in a region below the knee; and then entering the body through a pedal access point at step 120. Subsequently at step 130, utilizing an ultrasound machine in conjunction with the radiopaque micro stent for guidance and delivery of the radiopaque micro stent, followed by at step 140 in proceeding retrograde through a tibial artery to deliver the radiopaque micro stent. Lastly at step 150, delivering and seating the stent via an image from the ultrasound machine and then at step 160, unblocking tibial artery occlusions.

(13) The method of treating critical limb ischemia (CLI) may further comprising the steps of: reutilizing the pedal access point; proceeding antegrade around the ankle to reach legions and occlusions on the opposing side of the pedal access point; and utilizing a continuous medical X-ray image for positioning and guidance.

(14) In an additional embodiment, the micro stent may comprise a Nitinol and Platinum composite comprising 90 percent Nitinol and 10 percent Platinum; and a structure comprising forty eight strands.

(15) In one embodiment, a medical device for use in a body lumen, comprising a braided composite of DFT® wires, comprising tubular-shaped body having a wall defining a pattern of struts, wherein the tubular-shaped body comprises a nickel-titanium alloy, said nickel-titanium alloy further comprising at least one additional element platinum.

(16) In additional embodiments, the medical device of claim 1, wherein the tubular-shaped body is a radiopaque stent. The medical device of claim wherein the device is radiopaque and comprises nitinol and additional element that may be chosen from the group consisting of iridium, platinum, rhenium, palladium, rhodium, silver, ruthenium, osmium, zirconium, and molybdenum.

(17) The micro stent is manufactured by utilizing individual strands of NiTi #1 DFT®-10% Platinum composition (Fort Wayne Metals) and braiding the wire into a stent in the body. When the wire is braided on a mandrel is then heat set and quenched forming the wires into the cylindrical configuration. The stent then undergoes a process to remove the oxide formed during heat treating.

(18) In a preferred embodiment, forty eight (48) strands NiTi #1 DFT®-10% Pt composition may be utilized. Although many rations of platinum to nitinol may be employed, including a of 5% to 50%, utilization of 10% Platinum to Nitinol ration represents an optimum compromise between visualization and mechanical performance as every increase in platinum, the wire becomes more visible but the material properties diminish, it becomes weaker and less flexible. In a further embodiment, Silk® NiTi (Fort Wayne Metals) may be utilized.

(19) In one embodiment, the micro stent may be employed in conjunction with a 3 French (Fr) compatible balloon (micro balloon) that can be placed under ultrasound as an outpatient procedure. This would allow the physician to dilate a de novo lesion or restenotic lesion in Rutherford 5 patients for therapy for CLI. The micro balloon's low profile, visibility under ultrasound, and high pressure capabilities will allow the physician to perform a staged therapy in the outpatient setting under ultrasound guidance.

(20) The micro stent, self-expanding stent, is disposed to be deployed from the lateral plantar to the distal PT and thus possess the capability to extend across the across the ankle joint. Thus the micro stent brings into play a stent which can sustain high filling pressure to the microcirculation for better and faster wound healing.

(21) The stent design allows for side branches to stay patent and what generally occurs once you put a stent across a side branch is that you see the ostum of that side branch get pinched. We know from experience that when we go back, that side branch either ends up with a trickle of flow or thrombus present. The phenomenon I see with this stent design is that you can put it across side branches and the side branches are flowing and filling. This would be welcome news for CLI patients.

(22) As CLI patients do not normally tolerate the viscosity of contrast and often have underlying renal issues, having the ability to treat patients comfortably with ultrasound guidance via a pedal approach in an outpatient setting is now a reality