Obviousness

Obviousness Analysis of US Patent 12496077 under 35 U.S.C. § 103

This section analyzes the obviousness of US Patent 12496077 under 35 U.S.C. § 103, considering combinations of prior art references and the motivation a person having ordinary skill in the art (POSA) would have had to combine them. The critical date for prior art is October 16, 2015, based on the priority date of U.S. Provisional Application 62/242,493.

A patent claim is obvious if "the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains." 35 U.S.C. § 103. The motivation to combine prior art references can come from the knowledge of a POSA, from the prior art reference itself, or from the nature of the problem to be solved. Simply listing prior art references is insufficient; the analysis must explain why a POSA would have been motivated to combine or modify the references with a reasonable expectation of success.

Device Claims 1, 2, and 3: Cannula with Stepped Distal End and Embedded Expandable Element/Funnel

• Claim 1: "A device for removing undesirable material, comprising: a cannula including a polymer wall, a stepped cannula distal end, and an expandable element coupled to the stepped cannula distal by a collar, where the expandable element and the collar are embedded within the polymer wall."
• Claim 2: "A device for removing undesirable material, which includes an aspiration catheter comprising a polymer wall, a stepped distal end, and an expandable funnel coupled to the stepped distal end by a collar, with the expandable funnel and the collar being embedded within the polymer wall."
• Claim 3: "A device further includes a catheter comprising a wall, a reinforcement member, a stepped catheter distal end, and an expandable element coupled to the stepped catheter distal end by a collar. The expandable element, reinforcement member, and the collar are embedded within the catheter wall."

Prior Art Considerations:

The patent itself describes various aspects of cannulas and expandable elements. For instance, the general concept of a cannula for removing undesirable material from the circulatory system is well-established. The patent mentions "catheter-based removal of blood clots from larger blood vessels (e.g., pulmonary arteries) and heart chambers has had limited success" and "aspiration techniques draw the clot into a catheter via suction."

The patent describes a cannula (10) that can have a "distal end (11) . . . in the shape of a funnel (20)" and mentions "a plurality of independent strips (31), each coupled at one end to distal end (11) of cannula (10)" to form the funnel (20). It also details a "sheath (21) circumferentially situated about distal end (11) of cannula (10)" designed to slide and expose/expand the funnel (20). The patent further introduces a "balloon (33) positioned circumferentially about cannula (10) and proximal to strips (31)" with an "attachment mechanism (34)" to deploy the strips (31) into a flared open position.

Regarding the "stepped cannula distal end," the patent states that "the distal most end of the inner shaft layer (124) extends a selected distance beyond the distal most end of the outer shaft layer (120), thereby creating a stepped distal end (138) of the suction cannula."

The concept of embedding components within a polymer wall, while specifically claimed, may be motivated by a desire to create a smooth outer surface, improve durability, or provide a more integrated structure.

Obviousness Combination for Device Claims:

A combination of the general knowledge of catheter-based thrombectomy with the specific disclosures within US12496077B2 itself (as prior art for later claims, or in the context of different embodiments within the same patent family) could render claims 1, 2, and 3 obvious.

For example, a POSA, seeking to improve the existing suction cannulas for en bloc clot removal, as described in the background of US12496077B2, would recognize the benefits of:

1. A stepped distal end: The patent explicitly teaches that a "stepped distal end (138)" is formed by the inner shaft layer extending beyond the outer shaft layer. This design would be obvious for facilitating the attachment of expandable elements or providing a smooth transition.
2. An expandable element/funnel: The patent describes various expandable funnel designs (e.g., funnel 20, independent strips 31, reinforcement arms 112, jacket 114) for engaging and capturing undesirable material. The need for such an element to capture material "substantially en bloc" is a stated problem the invention aims to solve.
3. A collar for coupling the expandable element: The patent repeatedly mentions the use of a "collar (118)" to connect reinforcement arms (112) or strips (31) to the cannula. This is a conventional mechanical attachment means.
4. Embedding within the polymer wall: Given the goal of creating a device for use within blood vessels, embedding internal components like expandable elements, collars, and reinforcement members within a polymer wall would be an obvious design choice for a POSA to achieve a smooth exterior, reduce potential for vessel trauma, and improve the overall integrity and maneuverability of the device. This addresses the problem of delivering such a device through tortuous vasculature and minimizing irritation to the vessel, as discussed in the patent (e.g., "jacket (36) . . . to protect the vessel from potential irritation").

Therefore, a POSA seeking to create an improved aspiration catheter for en bloc clot removal would be motivated to combine these known design principles and components, as explicitly taught or suggested within the comprehensive disclosure of US12496077B2 itself, to arrive at the claimed devices. The patent even discusses different manufacturing methods, including dipping layers to embed elements (e.g., reinforcement element 106).

Method Claim 1: Suction, Reinfusion, and Spaced Cannula Ends

• Claim 1: "A method for removing an undesirable material from within a vessel, comprising: maneuvering a first cannula having a distal end and an opposing proximal end to a site of interest within the vessel, such that the distal end of the first cannula is positioned adjacent the undesirable material; positioning a second cannula, in fluid communication with the first cannula, such that its distal end can be situated in spaced relation to the distal end of the first cannula; providing a suction force through the distal end of the first cannula to the site of interest, so as to remove, through the distal end of the first cannula, the undesirable material substantially en bloc from the site of interest; and reinfusing, through the distal end of the second cannula, any fluid removed along with the undesirable material to a location in spaced relation from the distal end of the first cannula."

Prior Art Considerations:

The concept of removing undesirable material from the circulatory system using a cannula and suction is disclosed in the patent's background, which refers to "aspiration techniques draw the clot into a catheter via suction."

The notion of filtering and reinfusing blood in a closed system is generally known in medical procedures. For example, US4919823A, while pertaining to blood bag systems, describes filtering red cell concentrate in a closed multiple blood bag system, and passing the filtered solution from one bag to another. While not directly related to in vivo clot removal, it demonstrates the known principle of filtering and returning blood components.

The patent explicitly details "system 1 for removing an undesirable material . . . and for reinfusion of fluid removed . . . back into a patient, in order to minimize fluid loss within the patient." It describes a "first or suction cannula (10)" and a "second or reinfusion cannula (16) in fluid communication with the exit port (152) of pump (15)," with the reinfusion cannula (16) designed to permit "filtered fluid . . . to be reinfused back into a patient at a desired site." Crucially, it states that "the distal end of the second cannula (16) may be situated in spaced relation to the distal end of the first cannula (10)." The patent also describes a "filter device (14) positioned in fluid communication with the first cannula (10)" and a "pump (15)" to provide suction and driving force for reinfusion.

Obviousness Combination for Method Claim 1:

A POSA in the field of interventional cardiology or vascular surgery, facing the problem of removing large blood clots without excessive fluid loss, as highlighted in the patent's background, would have been motivated to combine known aspiration techniques with fluid management principles.

Specifically, combining:

1. Aspiration for en bloc removal: The patent's own background acknowledges aspiration techniques for removing clots. The "en bloc" removal is a stated goal of the invention.
2. Fluid reinfusion: The need to minimize fluid loss during procedures involving blood aspiration is a well-understood medical problem. The general concept of filtering and reinfusing bodily fluids is known, as exemplified by blood bag systems with integral filters.
3. Spaced cannula ends: The patent explicitly describes placing the reinfusion cannula's distal end "in spaced relation to the distal end of the first cannula." This arrangement would be an obvious design choice to prevent the reinfused fluid from interfering with the suction process or immediately being re-aspirated. This separation minimizes turbulence at the aspiration site and ensures efficient reinfusion into the patient's circulatory system.

The patent itself describes the "systems and methods of the present invention may simultaneously reinfuse aspirated (i.e., removed) and filtered fluid, such as blood, back into the patient on a substantially continuous basis to minimize any occurrences of fluid loss and/or shock." This statement, describing the core elements of the method claim, demonstrates that these features were known and desirable in the context of the invention.

Therefore, a POSA would find it obvious to combine the established practice of catheter-based aspiration with the known principles of fluid conservation and recirculation, employing two cannulas with spaced ends to effectively remove undesirable material while minimizing fluid loss, as comprehensively described within the patent's own disclosure.

Method Claim 2: Outer and Inner Suction Cannulas

• Claim 2: "A method of removing undesirable material, which includes an outer suction cannula and an inner suction cannula, the outer suction cannula having an outer suction cannula lumen and the inner suction cannula having an inner suction cannula lumen, wherein the inner suction cannula is situated within the outer suction cannula lumen."

Prior Art Considerations:

The patent describes a "multiple suction cannula device" where "the outer suction cannula (130) may be sized up to 24 F . . . the inner suction cannula (132) will be smaller, such as 12 F, and may also consist of any of the above described suction cannula embodiments." It further states that "the inner suction cannula (132) is sized such that it can independently coaxially move within the outer suction cannula (130)."

The patent articulates the "advantage of using a smaller inner suction cannula (132) is to provide a system that allows the user to easily maneuver the inner suction cannula (132) into smaller vasculature that the outer suction cannula (130) could not fit." It explains that "it is common for undesirable material to be located along large sections of vasculature" and "extends into smaller diameter vessels that do not easily permit a 24 F sized device, such as the outer suction cannula (130)." The smaller inner cannula can then "more easily fit into these smaller diameter vessels and capture the undesirable material."

Obviousness Combination for Method Claim 2:

A POSA facing the problem of removing widespread undesirable material that extends into smaller, more tortuous vessels, as explicitly outlined in the patent, would find the combination of an outer and inner suction cannula obvious. The motivation to combine these elements comes directly from the nature of the problem to be solved.

1. Outer suction cannula: Provides the primary means of aspiration for larger vessels, as described throughout the patent.
2. Inner suction cannula coaxially movable within the outer cannula: This configuration would be an obvious solution to access smaller, more distal vasculature. The inherent problem of a single large cannula being unable to reach smaller vessels would lead a POSA to consider a smaller, more maneuverable cannula that can be deployed through the larger one. The "smaller inner suction cannula (132) is sized such as it can more easily fit into these smaller diameter vessels and capture the undesirable material."

The patent itself provides the clear motivation and solution for this combination, stating that the inner cannula allows the user to "easily maneuver the inner suction cannula (132) into smaller vasculature that the outer suction cannula (130) could not fit." This directly addresses the limitation of single, larger cannulas and proposes a straightforward, incremental improvement that a POSA would readily conceive. The operation of advancing the inner cannula beyond the outer one and activating suction is also detailed in the patent.