Imperative Care v. Inari Medical — PTAB Invalidates Hemostasis-Valve Patent Claims

Background

Imperative Care challenged claims 1–8 and 12–19 of Inari Medical’s U.S. Patent No. 11,865,291 in inter partes review. The patent covers a hemostasis valve used with catheters and other instruments during intravascular procedures. Its valve uses a collapsible tubular sidewall and a looped filament that tightens around the tube, reducing the lumen’s diameter to control bleeding and maintain a seal around instruments of different sizes and shapes.

The principal independent claim required a support, movable actuator, collapsible tubular sidewall, looped filament, and spring that pulls the filament to reduce the lumen diameter. Another independent claim placed a similar valve in an aspiration-catheter system.

Imperative relied primarily on Schaffer, which disclosed a spring-biased hemostasis valve using U-shaped actuating members, together with Hartley’s flexible string or Eller’s flexible wire. It argued that a skilled medical-device engineer would have replaced Schaffer’s actuating members with a looped string or wire to obtain more uniform constriction around tools. Inari responded that Schaffer already produced a complete seal, the proposed substitution would alter its operating principle, and the combination depended on hindsight.

The Court’s Holding

The Patent Trial and Appeal Board held every challenged claim unpatentable as obvious. It did not accept Imperative’s anticipation theory or its argument that Schaffer alone made the claims obvious, because Schaffer did not adequately disclose the claimed flexible filament. The successful grounds instead combined Schaffer with Hartley or Eller.

The Board found that Hartley’s string and Eller’s wire supplied the missing looped-filament feature. Replacing Schaffer’s two U-shaped members with a flexible string or wire was a predictable substitution of known components. A skilled artisan could have attached the filament ends to Schaffer’s opposing actuator buttons using familiar methods such as knotting, fusing, or welding.

The combination also offered a practical reason to make the change. A flexible loop could conform more closely to the exterior of instruments and produce more uniform constriction than rigid U-shaped members, especially across varied tool shapes and sizes. Inari’s expert had acknowledged that a filament’s cinching action could improve sealing around large-bore catheters as a matter of ordinary mechanics.

The Board rejected Inari’s argument that Schaffer’s existing seal removed any motivation to improve it. Schaffer described a nearly fluid- or gas-tight seal, not a perfect one, and its highly compliant central sealing material was preferred rather than mandatory. Nor did the possibility that a filament could perform worse in some configurations defeat obviousness. Patent law does not require a proposed combination to be the best solution in every circumstance; it need only be a suitable, predictable option.

The Board also found no persuasive evidence of hindsight. Hartley and Eller themselves showed several established ways to use strings and wires to constrict hemostasis-valve lumens. A person of ordinary skill is presumed to bring ordinary creativity to those teachings. Inari offered no objective evidence of nonobviousness, such as commercial success or industry praise, to counter the technical case.

Key Takeaways

• A prior-art device need not be defective before an engineer has reason to improve it; an already functional seal may still invite a more conforming mechanism.
• Obviousness does not require the combined design to outperform every alternative in every use case. A suitable and predictable option can be enough.
• Known attachment and assembly techniques may fill implementation details when the references supply the core components and motivation.
• The decision invalidates claims 1–8 and 12–19 of the ’291 patent, including both the stand-alone hemostasis-valve claims and the aspiration-catheter-system claims.

Why It Matters

This is another significant PTAB loss for Inari in its broader medical-device dispute with Imperative Care. The Board identified several related reviews in which claims from the same patent family have also been found unpatentable, while the Northern District of California infringement action remains stayed.

For medical-device patent drafting and enforcement, the ruling illustrates the risk of claiming a familiar mechanism by swapping one known force-transmission element for another. When the record shows that engineers already used flexible strings or wires for the same sealing function, emphasizing improved conformity may support the challenger’s motivation-to-combine theory rather than establish patentable invention.

Surfaced via Law360 IP.