The FlowSaver Blood Return System accessory allows for autologous injection of aspirated blood from the FlowTriever Retrieval/Aspiration System embolectomy procedure by dual layer 40 µ/200 µ filtration to minimize intraprocedural blood loss.

AI/ML Overview

The provided document is an FDA 510(k) clearance letter for the FlowSaver Blood Return System. It primarily focuses on regulatory approval based on demonstrating substantial equivalence to a predicate device. It briefly mentions "Non-Clinical Testing" and "Clinical Testing" as part of the evidence presented for substantial equivalence.

However, the document does not contain detailed information about acceptance criteria or the specific study design, performance metrics, sample sizes, expert qualifications, or ground truth establishment methods for a new AI/ML-driven device. The request asks for details typically found in the clinical study section of a 510(k) submission or a peer-reviewed publication for an AI/ML medical device.

The "Clinical Testing" section states: "Post-market clinical data from PEERLESS (NCT05111613), FLAME (NCT04795167), and FLASH (NCT03761173) studies demonstrated the FlowSaver's filtration efficiency and safety without use of the second filter in support of substantial equivalence." This refers to clinical studies on the device's performance in a clinical setting, but it does not describe a study to prove the device meets acceptance criteria in the context of an AI/ML algorithm or a new diagnostic tool where performance metrics like sensitivity, specificity, or AUC are typically evaluated. The "acceptance criteria" mentioned in the request, in the context of AI, usually refers to pre-defined thresholds for these performance metrics.

Therefore, many of the requested details cannot be extracted from this document, as it outlines the regulatory approval process for a physical medical device with a labeling change, not a software-as-a-medical-device (SaMD) or AI-enabled diagnostic tool requiring specific AI model validation studies.

Here's a breakdown of what can be extracted and what cannot:

Information Present in the Document:

1. A table of acceptance criteria and the reported device performance:
- The document implies acceptance criteria were met for "Filtration Efficiency" in non-clinical testing.
- For clinical studies, it states the studies "demonstrated the FlowSaver's filtration efficiency and safety without use of the second filter."
- However, no specific numerical acceptance criteria (e.g., minimum filtration percentage) or detailed performance results tables are provided.
2. Sample sizes used for the test set and the data provenance:
- The document mentions clinical studies: PEERLESS (NCT05111613), FLAME (NCT04795167), and FLASH (NCT03761173).
- Sample sizes (NCT numbers are provided, which could be looked up, but not directly stated in the document for the purpose of this submission).
- Data provenance (country of origin, retrospective/prospective) is not explicitly stated in this document but would be detailed in the full clinical study protocols.
7. The type of ground truth used:
- For filtration efficiency, the ground truth would be the measurement of particles/cellular components filtered out.
- For safety, it would be adverse event reporting and clinical outcomes.
- Not explicitly defined as "ground truth" in the AI/ML sense, but rather as measured performance and safety endpoints.

Information NOT Present in the Document (and likely irrelevant for this type of device clearance):

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g., radiologist with 10 years of experience): This is for expert-labeled ground truth, typically for image or signal interpretation. Not applicable here.
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set: Not applicable as it's not an AI diagnostic study needing expert adjudication.
5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance: This applies to AI-assisted human reading. Not applicable here.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done: Not applicable, as this is a physical device, not an algorithm.
8. The sample size for the training set: Not applicable, as no AI model is being "trained" in this context.
9. How the ground truth for the training set was established: Not applicable.

Summary of Device Acceptance and Study Information (Based on the Provided Text):

The FlowSaver Blood Return System is an autotransfusion apparatus that performs dual-layer 40 µ/200 µ filtration of aspirated blood during embolectomy procedures to minimize intraprocedural blood loss. The current 510(k) submission (K221483) is for a labeling change to remove the secondary filtration procedure, implying that the single-stage filtration by the FlowSaver alone is sufficient.

The acceptance criteria for the device, as evidenced by the studies, are related to its filtration efficiency and safety.

Table of Acceptance Criteria and Reported Device Performance:

Acceptance Criteria (Implied)	Reported Device Performance (as stated in document)
Filtration Efficiency	Non-Clinical Testing: "Filtration Efficiency" demonstrated compliance with product requirements. Test results: "all acceptance criteria were met; therefore, the device conforms to established product specifications." Clinical Testing: Post-market clinical data from PEERLESS (NCT05111613), FLAME (NCT04795167), and FLASH (NCT03761173) studies "demonstrated the FlowSaver's filtration efficiency... without use of the second filter." No specific quantitative metrics (e.g., % of particles removed) are provided in this regulatory letter, but the implication is that the performance was acceptable to the FDA.
Safety (without secondary filter)	Clinical Testing: Post-market clinical data from PEERLESS (NCT05111613), FLAME (NCT04795167), and FLASH (NCT03761173) studies "demonstrated the FlowSaver's... safety without use of the second filter." This suggests an acceptable safety profile was observed in these studies, supporting the removal of the secondary filtration step from the instructions for use.
Functional Performance	Non-Clinical Testing: The document states that various tests were leveraged from the predicate device (K210176) and "demonstrated that all acceptance criteria were met; therefore, the device conforms to established product specifications." These tests include: Visual Inspection, Dimensional Inspection, Engagement & Disengagement Force Testing, Flow Rate Testing, Media Integrity testing, Leakage Testing, Vacuum Testing, Clot Burden Filtration Validation, Simulated Use and Tensile Testing, Simulated Use and Torque Testing, Burst Testing, Hematocrit Testing, Mechanical Hemolysis Testing. Numerical acceptance criteria and detailed performance of these tests are not provided in this summary.

Study Information:

Sample size used for the test set and the data provenance:
- Test Set Sample Size: Not explicitly stated as a single "test set" size for the purpose of this submission. The document references post-market clinical data from three studies: PEERLESS (NCT05111613), FLAME (NCT04795167), and FLASH (NCT03761173). The full sample size for these studies would need to be checked in their respective ClinicalTrials.gov entries or publications. The document implies that data from these studies collectively served as the clinical evidence.
- Data Provenance: Not specified in the provided document (e.g., country of origin, retrospective or prospective). These details would be available in the protocols/publications of the mentioned clinical studies. The mention of "post-market clinical data" suggests the data was collected after the initial marketing of the device, likely prospectively as part of ongoing clinical trials.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not applicable. This is not an AI/ML diagnostic device requiring expert labeling of ground truth. The "ground truth" for this device's performance would be objective measurements of filtration efficiency (e.g., particle counts, volume filtered) and clinical outcomes related to safety.
Adjudication method (e.g. 2+1, 3+1, none) for the test set: Not applicable. This concept is typically relevant for studies validating AI models against expert interpretation, not for evaluating a physical filtration device.
If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance: Not applicable. This device is not an AI-assisted reading tool.
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done: Not applicable. This is a physical medical device, not a standalone AI algorithm.
The type of ground truth used:
- For filtration efficiency: Likely quantitative measurement of filtered components (e.g., blood cell counts, clot burden measurements) before and after filtration, or particle size analysis.
- For safety: Clinical outcomes data, adverse event reporting, and potentially hematological parameters (e.g., mechanical hemolysis testing mentioned in non-clinical tests).
The sample size for the training set: Not applicable. This is not an AI/ML device where a "training set" for an algorithm is used.
How the ground truth for the training set was established: Not applicable, for the same reason as above.

Summary

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February 17, 2023

Inari Medical, Inc. Kaitlyn Weinkauf Sr. Regulatory Affairs Specialist 6001 Oak Canyon, Suite 100 Irvine, California 92618

Re: K221483

Trade/Device Name: FlowSaver Blood Return System Regulation Number: 21 CFR 868.5830 Regulation Name: Autotransfusion Apparatus Regulatory Class: Class II Product Code: CAC Dated: December 16, 2022 Received: December 20, 2022

Dear Kaitlyn Weinkauf:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting of medical device-related adverse events) (21 CFR 803) for

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devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.

For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely.

Nicole M. Gillette -S

Nicole Gillette Assistant Director DHT2B: Division of Circulatory Support, Structural and Vascular Devices OHT2: Office of Cardiovascular Devices Office of Product Evaluation and Quality Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known)

K221483

Device Name FlowSaver Blood Return System

Indications for Use (Describe)

The FlowSaver Blood Return System is used with Triever Catheters for autologous blood transfusion.

Type of Use (Select one or both, as applicable)

X Prescription Use (Part 21 CFR 801 Subpart D)

| Over-The-Counter Use (21 CFR 801 Subpart C)

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510(K) SUMMARY

Date prepared	February 16, 2023
Name	Inari Medical, Inc.6001 Oak Canyon, Suite 100Irvine, CA 92618949.600.8433
Contact person	Kaitlyn WeinkaufSr. Regulatory Affairs Specialist
Trade name	FlowSaver Blood Return System
Common name	Blood filter
Regulation name	Autotransfusion apparatus
Classification number	21 CFR 868.5830
Product code	CAC
Regulatory class	II
Predicate device	FlowSaver Blood Return System (K210176)
Description	The FlowSaver Blood Return System accessory allows for autologousinjection of aspirated blood from the FlowTriever Retrieval/AspirationSystem embolectomy procedure by dual layer 40 µ/200 µ filtration tominimize intraprocedural blood loss.
Indications for Use	The FlowSaver Blood Return System is used with Triever Catheters forautologous blood transfusion.
Device modification	The purpose of this submission is a labeling change to remove the secondaryfiltration procedure that is performed after the initial filtration with theFlowSaver Blood Return System.
Comparison ofTechnologicalCharacteristics withthe Predicate Device	There is no change to the principles of operation, indications for use,intended use, fundamental scientific technology, or technologicalcharacteristics between the proposed FlowSaver Blood Return System andthe predicate device.

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Summary ofsubstantialequivalence	The proposed FlowSaver Blood Return System accessory and the predicate device have the same indications for use, intended use, principles of operation, and fundamental scientific technology.
	Non-Clinical TestingThe following verification test demonstrated compliance with product requirements:• Filtration EfficiencyThe following testing was leveraged from the predicate device (K210176):• Visual Inspection• Dimensional Inspection• Engagement & Disengagement Force Testing• Flow Rate Testing• Media Integrity testing• Leakage Testing• Vacuum Testing• Clot Burden Filtration Validation• Simulated Use and Tensile Testing• Simulated Use and Torque Testing• Burst Testing• Hematocrit Testing• Mechanical Hemolysis TestingTest results demonstrated that all acceptance criteria were met; therefore, the device conforms to established product specifications.Clinical TestingPost-market clinical data was used to demonstrate the safety and effectiveness of the FlowSaver Blood Return System's use without a secondary filtration procedure. Post-market clinical data from PEERLESS (NCT05111613), FLAME (NCT04795167), and FLASH (NCT03761173) studies demonstrated the FlowSaver's filtration efficiency and safety without use of the second filter in support of substantial equivalence.ConclusionThe proposed labeling change to the FlowSaver Blood Return System does not change its intended use nor does it change the principles of operation. The verification testing results demonstrate that the proposed FlowSaver Blood Return System is substantially equivalent to the predicate device.

Summary ofsubstantialequivalence

The proposed FlowSaver Blood Return System accessory and the predicate device have the same indications for use, intended use, principles of operation, and fundamental scientific technology.

Non-Clinical TestingThe following verification test demonstrated compliance with product requirements:• Filtration EfficiencyThe following testing was leveraged from the predicate device (K210176):• Visual Inspection• Dimensional Inspection• Engagement & Disengagement Force Testing• Flow Rate Testing• Media Integrity testing• Leakage Testing• Vacuum Testing• Clot Burden Filtration Validation• Simulated Use and Tensile Testing• Simulated Use and Torque Testing• Burst Testing• Hematocrit Testing• Mechanical Hemolysis TestingTest results demonstrated that all acceptance criteria were met; therefore, the device conforms to established product specifications.Clinical TestingPost-market clinical data was used to demonstrate the safety and effectiveness of the FlowSaver Blood Return System's use without a secondary filtration procedure. Post-market clinical data from PEERLESS (NCT05111613), FLAME (NCT04795167), and FLASH (NCT03761173) studies demonstrated the FlowSaver's filtration efficiency and safety without use of the second filter in support of substantial equivalence.ConclusionThe proposed labeling change to the FlowSaver Blood Return System does not change its intended use nor does it change the principles of operation. The verification testing results demonstrate that the proposed FlowSaver Blood Return System is substantially equivalent to the predicate device.

Regulation Number and Section

§ 868.5830 Autotransfusion apparatus.

(a)
Identification. An autotransfusion apparatus is a device used to collect and reinfuse the blood lost by a patient due to surgery or trauma.(b)
Classification. Class II (performance standards).