DCT

5:24-cv-03117

Inari Medical Inc v. Imperative Care Inc

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Key Events
Amended Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 5:24-cv-03117, N.D. Cal., 05/29/2025
  • Venue Allegations: Plaintiff alleges venue is proper in the Northern District of California because Defendant maintains its principal place of business in Campbell, Santa Clara County, and has committed acts of patent infringement in the district.
  • Core Dispute: Plaintiff alleges that Defendant’s Symphony Thrombectomy System infringes eleven patents related to catheter-based systems and methods for the intravascular removal of blood clots.
  • Technical Context: The technology lies in the field of mechanical thrombectomy, a medical procedure using catheter-based devices to remove blood clots (thrombi or emboli) from blood vessels to treat life-threatening conditions like pulmonary embolism and deep vein thrombosis.
  • Key Procedural History: The complaint alleges that Plaintiff provided Defendant with pre-suit notice of potential infringement through a series of letters and emails beginning in September 2023, approximately four months before the original complaint was filed and continuing through April 2024. Defendant allegedly refused to provide a sample product for analysis, citing proprietary concerns, and later responded to the notice by arguing the patents were invalid based on prior art.

Case Timeline

Date Event
2017-09-06 Earliest Priority Date for ’921, ’012, ’291, ’384 Patent Family
2018-01-26 Earliest Priority Date for ’580, ’669, 12-’333 Patent Family
2018-08-13 Earliest Priority Date for ’910, 11-’333, ’005, ’691 Patent Family
2023-01-17 U.S. Patent No. 11,554,005 Issues
2023-02-01 Defendant receives FDA clearance for Symphony system (approx.)
2023-07-01 Defendant begins marketing and selling Symphony system (approx.)
2023-07-11 U.S. Patent No. 11,697,012 Issues
2023-09-05 U.S. Patent No. 11,744,691 Issues
2023-09-01 Plaintiff sends first notice letter to Defendant (approx.)
2023-12-01 Defendant replies to notice letter, refusing to provide a sample
2023-12-19 U.S. Patent No. 11,844,921 Issues
2024-01-09 U.S. Patent No. 11,865,291 Issues
2024-01-15 Defendant provides substantive response to notice letter
2024-04-24 Plaintiff sends second notice letter to Defendant
2024-04-30 U.S. Patent No. 11,969,333 Issues
2024-05-07 U.S. Patent No. 11,974,910 Issues
2024-06-25 U.S. Patent No. 12,016,580 Issues
2024-10-08 U.S. Patent No. 12,109,384 Issues
2024-12-03 U.S. Patent No. 12,156,669 Issues
2025-02-14 Plaintiff sends e-mail notice regarding forthcoming 12-’333 Patent
2025-03-04 U.S. Patent No. 12,239,333 Issues
2025-05-29 Third Amended Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 11,974,910 - "System for Treating Embolism and Associated Devices and Methods"

The Invention Explained

  • Problem Addressed: The patent family specification notes that prior art clot-removal devices were often complex, could cause trauma to the blood vessel, were difficult to fix against the vessel wall, and were frequently ineffective at capturing the clot material (’333 Patent, col. 2:33-44).
  • The Patented Solution: The invention is a "telescoping" clot aspiration system designed for improved clot removal. It comprises two distinct catheter assemblies: a larger, first catheter and a smaller, second catheter that can be advanced through the first one for extended reach. Each catheter is connected to its own vacuum source via a fluid control device. This device allows a vacuum to be "pre-charged" in the pressure source while disconnected from the catheter, and then rapidly applied to the catheter's tip to generate powerful, focused suction on the clot material (’910 Patent, Abstract; col. 5:6-24).
  • Technical Importance: This dual-catheter, pre-charged vacuum approach allows for both large-bore aspiration for proximal clots and targeted aspiration for more distal or difficult-to-reach clots within the same procedure, potentially increasing the efficiency and effectiveness of clot removal (Compl. ¶20).

Key Claims at a Glance

  • The complaint asserts independent claim 1 and dependent claim 3 (Compl. ¶67).
  • The essential elements of independent claim 1 include:
    • A clot treatment system for pulmonary embolism comprising a first clot aspiration assembly and a second clot aspiration assembly.
    • The first assembly includes a first catheter, a first pressure source, and a first movable fluid control device with at least two positions (disconnected and connected).
    • The second assembly includes a second catheter (size 16 French or greater) advanceable through the first catheter, a second pressure source, and a second movable fluid control device.
    • Both pressure sources are configured to generate vacuum pressure while the respective fluid control devices are in the disconnected position.
    • Upon moving the control device to the connected position, the vacuum pressure is applied to the respective catheter to generate suction.

U.S. Patent No. 11,969,333 - "System for Treating Embolism and Associated Devices and Methods"

The Invention Explained

  • Problem Addressed: The patent addresses the same problems as the ’910 Patent, as they share a common specification (Compl. ¶92). Prior art devices were complex, traumatic, and ineffective at clot capture (’333 Patent, col. 2:33-44).
  • The Patented Solution: This patent claims a method for treating deep vein thrombosis (DVT). The method involves advancing an aspiration catheter to the clot, where the catheter is fluidly connected to a clot canister and an aspiration source. A key step is generating vacuum pressure in the canister while a valve between the canister and catheter is closed. The valve is then moved to an open position, which applies the pre-charged vacuum to the catheter to aspirate the clot and blood into the canister, where a filter separates the clot from the blood (’333 Patent, cl. 20).
  • Technical Importance: By pre-charging the vacuum and then rapidly opening a valve, the method creates a powerful vacuum impulse at the catheter tip, which can be more effective at dislodging and removing clot material than simply applying continuous, steady suction (’333 Patent, col. 4:17-25).

Key Claims at a Glance

  • The complaint asserts independent claim 20 and dependent claim 22 (Compl. ¶91).
  • The essential elements of independent claim 20 include:
    • A method of treating DVT within a patient's vasculature.
    • Advancing an aspiration catheter so its distal end is proximate to the DVT.
    • The catheter's lumen is fluidly coupled to a clot canister and an aspiration source.
    • Generating vacuum pressure in the canister while a valve between the catheter and canister is in a first (closed) position.
    • Moving the valve to a second (open) position, thereby applying the vacuum to the catheter's lumen to aspirate the clot and blood into the canister.
    • The clot canister includes a filter to separate the aspirated blood from the clot.

U.S. Patent No. 11,554,005 - "System for Treating Embolism and Associated Devices and Methods"

  • Technology Synopsis: This patent, from the same family as the ’910 and ’333 patents, discloses a vacuum aspiration system that includes a housing with an on-off flow control, a catheter, a clot canister, and an improved hemostasis valve. The hemostasis valve is designed to receive a second catheter and uses a filament-and-spring mechanism to constrict a lumen and create a seal (Compl. ¶116; ’005 Patent, cl. 10).
  • Asserted Claims: At least claim 10 (Compl. ¶117).
  • Accused Features: The controller handles of the Symphony system are accused of being the claimed "housing," and the hemostasis valve within those handles is accused of infringing the claimed valve structure (Compl. ¶¶121, 123-124).

U.S. Patent No. 11,744,691 - "System for Treating Embolism and Associated Devices and Methods"

  • Technology Synopsis: This patent discloses an aspiration system with an "accelerated response," comprising a pump, a first chamber, a removable second chamber (clot canister) between the pump and the catheter, and a user-actuatable valve. The system is designed to build negative pressure in the chambers while the valve is closed and then open the valve to create a rapid pressure decrease in the catheter for aspiration (Compl. ¶136; ’691 Patent, cl. 14).
  • Asserted Claims: At least claims 14 and 22 (Compl. ¶137).
  • Accused Features: The Symphony system, including the Truvic Generator (aspiration pump), Truvic Canister (first chamber), and clot canister on the controller handle (second chamber), is alleged to practice the claimed system and method for treating DVT (Compl. ¶¶144, 146, 151).

U.S. Patent No. 11,844,921 - "Hemostasis Valves and Methods of Use"

  • Technology Synopsis: This patent discloses a hemostasis valve with an elongate, constrictable lumen. The valve features an "active tensioning mechanism" with an actuator (e.g., button) coupled to a filament that wraps around the lumen. A biasing member (e.g., spring) biases the actuator to a first, constricted position to seal the lumen (Compl. ¶¶161-162; ’921 Patent, cl. 1). Claim 10 adds a second actuator, filament, and biasing member.
  • Asserted Claims: At least claims 1 and 10 (Compl. ¶163).
  • Accused Features: The hemostasis valves in the Symphony controller handles, which are operated by buttons, are alleged to infringe. The buttons, levers, filaments, and springs of the accused valve are alleged to correspond to the claimed actuator, filament, and biasing member elements (Compl. ¶¶167, 169, 171, 173).

U.S. Patent No. 11,697,012 - "Hemostasis Valves and Methods of Use"

  • Technology Synopsis: This patent, from the same family as the ’921 patent, claims an aspiration catheter system that incorporates a hemostasis valve on its proximal end. The valve includes a collapsible tubular sidewall and a constricting mechanism with at least a first actuator, a first filament looped around the sidewall, and a first spring to move the actuator and tighten the loop (Compl. ¶186; ’012 Patent, cl. 1).
  • Asserted Claims: At least claim 1 (Compl. ¶187).
  • Accused Features: The Symphony system's 16F and 24F catheters with their controller handles and integrated hemostasis valves are accused of infringement. The buttons, levers, filaments, and torsion springs of the accused valves are alleged to meet the claim limitations for the actuator, filament, and spring (Compl. ¶¶191, 192, 196).

U.S. Patent No. 11,865,291 - "Hemostasis Valves and Methods of Use"

  • Technology Synopsis: This patent, from the same family as the ’921 patent, discloses a valve with a support, an actuator with a first member movably coupled to the support, a collapsible tubular sidewall, a filament looped around the sidewall and connected to the first member, and a spring configured to move the first member to pull the filament and reduce the lumen's diameter (Compl. ¶209; ’291 Patent, cl. 1).
  • Asserted Claims: At least claim 1 (Compl. ¶210).
  • Accused Features: The hemostasis valves within the Symphony controller handles are accused of infringement. The complaint identifies the plastic housing as the "support," the button/lever/pin mechanism as the "actuator," the braided lines as the "filament," and the torsion springs as the "spring" (Compl. ¶¶214, 215, 218, 219).

U.S. Patent No. 12,016,580 - "Single Insertion Delivery System for Treating Embolism and Associated Systems and Methods"

  • Technology Synopsis: This patent claims a method for intravascular clot treatment involving a sequence of steps: positioning a catheter, pre-charging a vacuum, aspirating a first portion of a clot, unsealing an attachment member on the catheter, and then advancing a separate interventional device (like the accused ProHelix) through the catheter to engage a second portion of the remaining clot (Compl. ¶231; ’580 Patent, cl. 1). Claims 18 and 19 add collecting the aspirated clot in a removable filter.
  • Asserted Claims: At least claims 1, 18, and 19 (Compl. ¶233).
  • Accused Features: The use of the Symphony system in combination with its ProHelix device is alleged to practice the claimed method. The complaint alleges that users are taught to first aspirate with the catheter, then unseal the hemostasis valve (attachment member) to advance the ProHelix device to engage remaining clot (Compl. ¶¶239, 246, 247).

U.S. Patent No. 12,109,384 - "Hemostasis Valves and Methods of Use"

  • Technology Synopsis: This patent, from the same family as the ’921 patent, discloses a valve assembly with a tubular member, a first flexible filament in a first loop, a second flexible filament in a second loop, and a pair of actuators. Each filament is acted upon by both actuators to constrict or loosen the loops, and the actuators are biased to the constricted position (Compl. ¶264; ’384 Patent, cl. 1).
  • Asserted Claims: At least claims 1 and 3 (Compl. ¶265).
  • Accused Features: The dual-button hemostasis valves in the Symphony system are accused of infringement. The complaint alleges the valve has two braided filaments (lines), each acted upon by the two button/lever actuators to constrict the lumen (Compl. ¶¶270, 272, 273, 274).

U.S. Patent No. 12,156,669 - "Single Insertion Delivery System for Treating Embolism and Associated Systems and Methods"

  • Technology Synopsis: This patent, from the same family as the ’580 patent, claims an aspiration system comprising a vacuum source, a catheter, and a filter chamber with specific port configurations. It includes a flow controller between the filter and catheter, and a separate hemostasis valve that is fluidically coupled to the catheter along a second fluid path (Compl. ¶¶288-289; ’669 Patent, cl. 15).
  • Asserted Claims: At least claim 15 (Compl. ¶290).
  • Accused Features: The Symphony system is alleged to be the claimed aspiration system. The complaint identifies the Truvic Generator as the "vacuum source," the controller handle's clot canister as the "filter chamber," the vacuum lever as the "flow controller," and the separate button-operated valve as the "hemostasis valve" (Compl. ¶¶294, 296, 297, 305, 307).

U.S. Patent No. 12,239,333 - "Single Insertion Delivery System for Treating Embolism and Associated Systems and Methods"

  • Technology Synopsis: This patent, from the same family as the ’580 patent, claims a clot collection reservoir with a partially transparent housing, specific port configurations, and a removable, substantially cylindrical filter. The filter is configured to enclose an interior region around the second (outlet) port, allowing blood to pass through while trapping clot material (Compl. ¶¶317-318; 12-’333 Patent, cl. 1).
  • Asserted Claims: At least claim 1 (Compl. ¶319).
  • Accused Features: The clot canister on the Symphony controller handles is accused of being the claimed reservoir. The complaint alleges it has a sealed, partially transparent housing and a removable cylindrical filter that functions as claimed (Compl. ¶¶323, 329, 337).

III. The Accused Instrumentality

Product Identification

Defendant's Symphony Thrombectomy System ("Symphony" or "Symphony system") and its components, including the 16F and 24F Symphony Catheters, the Symphony ProHelix, the Truvic Generator, and the Truvic Canister (Compl. ¶28).

Functionality and Market Context

The Symphony system is designed for the non-surgical removal of blood clots from blood vessels using controlled aspiration (Compl. ¶28). The system employs a "telescoping" design where a smaller 16F catheter can be advanced through a larger 24F catheter to extend its reach to a thrombus (Compl. ¶28). Aspiration is provided by a Truvic Generator (a vacuum pump) connected to the catheters (Compl. ¶28). The system also includes an optional, manually rotated "ProHelix" device that can be introduced through the catheter to mechanically engage and disrupt clot material (Compl. ¶28). The complaint alleges that the Symphony system's design "significantly overlaps with and mirrors" Plaintiff's FlowTriever system and that Defendant is targeting the market created by Plaintiff (Compl. ¶¶32-33). The Symphony system received FDA clearance for DVT treatment in February 2023 and began marketing in mid-2023 (Compl. ¶¶29-30). This annotated diagram from the complaint shows the Symphony system's handle and its primary components. (Compl. p. 19).

IV. Analysis of Infringement Allegations

U.S. Patent No. 11,974,910 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a first clot aspiration assembly, including: a first catheter; a first pressure source; and a first fluid control device between the first catheter and the first pressure source... The Symphony system includes a 24F catheter (first catheter), a vacuum pump and clot canister (first pressure source), and a controller handle with a "Dual-Action Vacuum Control" lever (first fluid control device). ¶72 col. 5:6-24
wherein the first fluid control device is movable between (a) a first position in which the first pressure source is fluidly disconnected from the first catheter and (b) a second position in which the first pressure source is fluidly connected... The Dual-Action Vacuum Control lever on the 24F catheter handle is alleged to move between an "off" position that fluidly disconnects the vacuum source and an "on" position that fluidly connects it. ¶73 col. 5:10-15
wherein the first pressure source is configured to generate vacuum pressure while the first fluid control device is in the first position... upon movement... the vacuum pressure is applied to the first catheter to generate suction... The Truvic Generator (pressure source) allegedly creates a vacuum in the clot canister while the control lever is in the "off" position. When the lever is moved to the "on" position, this pre-charged vacuum is applied to the 24F catheter to generate suction. ¶74 col. 5:16-24
a second clot aspiration assembly, including: a second catheter advanceable through the first catheter, wherein the second catheter has a size of 16 French or greater... The Symphony system includes a 16F catheter (second catheter) that is "shaped to be telescoped through the 24F catheter" to reach a pulmonary embolism. ¶75 col. 5:25-34
a second pressure source; and a second fluid control device between the second catheter and the second pressure source...movable between (a) a first position...disconnected...and (b) a second position...connected... The 16F catheter has its own controller handle with an identical Dual-Action Vacuum Control lever (second fluid control device) that connects to the same vacuum pump and canister (second pressure source) and operates in the same "on"/"off" manner. ¶76 col. 5:35-44

U.S. Patent No. 11,969,333 Infringement Allegations

Claim Element (from Independent Claim 20) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of treating a deep vein thrombosis...advancing an aspiration catheter...such that a distal end portion...is positioned proximate to the deep vein thrombosis... The Symphony system is intended for use in the peripheral vasculature for treating DVT, and its 16F and 24F catheters are advanced through a patient's vasculature to a position proximate to the clot material. ¶¶96-98 col. 4:17-20
wherein a lumen of the aspiration catheter is fluidly coupled along a fluid path to a clot canister and an aspiration source proximal to the clot canister; The lumens of the Symphony catheters are fluidly coupled through their controller handles to a clot canister and a vacuum pump (aspiration source) that is located proximal to the canister. ¶99 col. 4:20-25
generating vacuum pressure within the clot canister via the aspiration source while a valve...is in a first position that inhibits fluid flow... The user sets the vacuum control lever ("valve") on the handle to the "OFF" position (inhibiting flow) and turns on the Truvic Generator (aspiration source) to build vacuum in the canister. ¶¶100-101 col. 4:25-31
moving the valve from the first position to a second position thereby applying the vacuum pressure to the lumen of the aspiration catheter such that at least a portion of the deep vein thrombosis...are aspirated into the clot canister... The user moves the vacuum control lever to the "ON" position, which applies the pre-charged vacuum to the catheter lumen to aspirate the DVT into the canister. ¶102 col. 4:32-38
and wherein the clot canister includes a filter configured to filter the blood from the portion of the deep vein thrombosis. The clot canisters of the Symphony handles allegedly contain a filter that separates aspirated blood from the clot material, allowing blood to pass through while trapping the clot. ¶103 col. 4:39-42
  • Identified Points of Contention:
    • Scope Questions: For the ’910 Patent, a question may arise as to whether the single Truvic Generator and Canister, which serves both catheters, can satisfy the claim limitations of a "first pressure source" for the first assembly and a distinct "second pressure source" for the second assembly, or if the shared components are construed as a single source for both. For the ’333 Patent, a central question will be whether Defendant's actions constitute "performing" the claimed method, raising issues of direct versus indirect infringement.
    • Technical Questions: A key technical question for both patents is whether the accused "Dual-Action Vacuum Control" lever operates in a manner that meets the specific claim requirements of a "fluid control device" or "valve" that is "movable between (a) a first position in which the pressure source is fluidly disconnected" and "(b) a second position in which the pressure source is fluidly connected." The complaint provides internal teardown photos to support this allegation, such as an annotated image showing the internal portion of the controller handle housing (Compl. p. 21). The defense may challenge whether the "off" position constitutes a true "fluidly disconnected" state as contemplated by the patent.

V. Key Claim Terms for Construction

  • The Term: "fluid control device" (in ’910 Patent, Claim 1) / "valve" (in ’333 Patent, Claim 20)
    • Context and Importance: The functionality of this component is central to the core inventive concept of pre-charging a vacuum and then rapidly applying it. The infringement analysis for both lead patents hinges on whether the accused Symphony system's "Dual-Action Vacuum Control" lever meets the specific two-position, connect/disconnect functionality required by these terms. Practitioners may focus on whether the "off" position creates a true fluidic disconnection sufficient to allow pressure to build independently in the source, as the patents describe.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification describes the element more generally as a "valve or other fluid control device" and notes it can be a "stopcock" or a "clamp" (’005 Patent, col. 5:6-14). This language may support a construction that is not limited to a specific mechanical structure, so long as it performs the function of regulating flow.
      • Evidence for a Narrower Interpretation: The detailed description emphasizes the function of allowing the pressure source to be activated "while the valve is closed, to charge a vacuum" before being "opened to apply the vacuum" (’005 Patent, col. 2:20-25). This could support a narrower construction requiring a robust seal in the "off" position sufficient to hold a significant pre-charged vacuum before application.
  • The Term: "a first pressure source" and "a second pressure source" (in ’910 Patent, Claim 1)
    • Context and Importance: Claim 1 recites two separate aspiration assemblies, each including its own pressure source. The accused Symphony system, however, appears to use a single Truvic Generator and Canister to supply vacuum for both the 16F and 24F catheters (Compl. ¶¶72, 76). The infringement analysis will turn on whether a single, shared vacuum-generating apparatus can be construed as meeting the "first pressure source" and "second pressure source" limitations.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The claims do not explicitly state the two pressure sources must be structurally independent or mutually exclusive. A plaintiff might argue that the same physical device, when used in conjunction with the first catheter assembly, constitutes the "first pressure source," and when used with the second, constitutes the "second pressure source."
      • Evidence for a Narrower Interpretation: The patent's summary describes "a first and second aspiration system comprising, respectively: a first and second catheter; a first and second pressure source" (’910 Patent, col. 16:21-24). The use of "respectively" and the separate recitation of each component for each system may suggest that the claim requires two physically distinct and independent pressure sources.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges inducement of infringement based on Defendant providing Instructions for Use (IFU), brochures, and animation videos that allegedly "detail how to use the Truvic Symphony system" in an infringing manner. It further alleges that Defendant's sales representatives attend procedures and instruct physicians on infringing methods (Compl. ¶¶82, 107). Contributory infringement is alleged on the basis that the Symphony system is not a staple article of commerce and is especially made for use in a patented process (Compl. ¶¶83, 108).
  • Willful Infringement: Willfulness allegations are based on both pre- and post-suit knowledge. The complaint alleges Plaintiff sent Defendant notice letters identifying specific patents beginning in September 2023, well before the lawsuit was filed, and that Defendant continued its accused activities after receiving these notices and after the filing of the original and amended complaints (Compl. ¶¶59-64, 84-86, 109-111).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of claim construction: can a single, shared vacuum generator and canister satisfy the claim language reciting "a first pressure source" and "a second pressure source," or does the claim require two physically distinct apparatuses? The resolution of this question will be critical to the infringement analysis of the dual-catheter system claims.
  • A key technical question will be one of operational equivalence: does the accused system's two-position vacuum control lever create a true "fluidic disconnection" that allows for the pre-charging of vacuum as taught by the patents, or is there a functional difference in its mechanism that places it outside the scope of the claims? The evidence from the complaint's product teardown visuals will be central to this factual dispute.
  • A central question for the method patents will be one of divided infringement: given that physicians, not the Defendant, perform the treatment methods, what evidence shows that the Defendant's instructions and product design actively induce every step of the claimed methods, thereby creating liability for indirect infringement?