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US 7,842,006 B2Granted
Thrombectomy microcatheter
AssigneeCFD Research Corporation
InventorsGuiren Wang, Shivshankar Sundaram, Kapil Pant, Jianjun Feng, Peter Storm
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AssigneeCFD Research Corporation
InventorsGuiren Wang, Shivshankar Sundaram, Kapil Pant, Jianjun Feng, Peter Storm
Estimating the term…
The present invention is an ultrasonic thrombectomy catheter that produces physical forces (shear rates) strong enough to emulsify obstructions such as thrombi and emboli without causing damage to arterial walls. This is accomplished by properly arranging piezoelectric transducers within a catheter and a tubular catheter head separated by a gap to generate acoustic streaming that simultaneously emulsifies the obstruction and sweeps resulting debris into a catheter lumen for removal. The open gap may be formed by supporting struts that connect the catheter to the catheter head. The design of the catheter tip allows the fabrication of catheters capable of removing partial or complete blockages from arteries and other vessels having diameters as small as 2 mm.
An apparatus for removing an obstruction from a physiological vessel in a subject, said apparatus comprising:
A method for removing an obstruction from a physiological vessel comprising:
Dependencies are inferred from the claim text.
From the US filing history. Foreign family members aren’t listed.
In direct contact with, or very close to, the obstruction or concrement: the ultrasound transducer being inside patient's body at the distal end…
Type of operation; Specification of treatment sites: operations on blood vessels
Implements for squeezing-off ulcers or the like on inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones;…
The ultrasound transducer being inside patient's body at the distal end of the catheter: electric leads passing through the catheter
About 1 month of term left · ends 17 Nov 2026 (estimated)
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1. Field of the Invention
FIG. 1 shows a diagram of a first embodiment of the present invention.
FIG. 2 shows experimental results demonstrating the tube effect.
FIG. 3 is a schematic of a second embodiment of the present invention.
FIG. 1 illustrates a longitudinal cross section of a first embodiment of the invention. Catheter 105 is connected to catheter head 110 by connecting struts 104. Catheter head 110 is a tube open at both ends (right). Catheter 105 and catheter head 110 are separated by a gap 130. Two piezo-electric transducers 100, each having opposing electrically conducting surfaces 102 and 103 for connection to electrical leads, not shown, are positioned such that the base of each transducer in located in the lumen of catheter 105 and the tip of each transducer is located just inside the lumen of catheter head 110. The position of each transducer tip relative to gap 130 is important for producing optimal acoustic streaming as shown in FIG. 2.
FIG. 2 shows the results of flow visualization experiments for several different distances between the tip of a piezo transducer fiber and the proximal end of a catheter head. Configurations with the fiber located both inside and outside the tube were tested. The catheter head does not significantly influence the fluid motion until it is moved very close to the fiber tip. At this point, the flow field increases dramatically to a maximum velocity in excess of 140 mm/s. The synergetic effect between the fiber and tube to increase flow velocity helps produce the shear forces needed to disrupt vessel blockages. The optimal location of piezo tip relative to the catheter head, or tube, as well as the length of the gap between the catheter and catheter head depend upon the a number of factors including the diameter of the catheter head, the size and number of piezo transducers, and the frequency of vibration.
A second embodiment of the thrombectomy microcatheter, shown in FIG. 3, comprises a piezo transducer 100 that spans a gap 130 separating a catheter 105 and a catheter head 110 connected by struts, or structural members 104. A power supply and instrument control unit provide electrical power to the piezo transducer through leads that run the length of the catheter. The piezo transducer is insulated using an electrically insulating coating material. FIG. 3 shows one mode of operation for this embodiment in which the catheter head is pushed through a blood clot 140 within a blood vessel 150 and shear stresses produced by fluid flowing into the gap fragments the clot. Small arrows in the figure indicate the flow of liquid generated by acoustic streaming, including areas of high shear near the gap 130. Fragments of the clot may then be removed by suction through a liquid-filled catheter lumen (not shown).