InThrill™ Thrombectomy System

K250421 · Inari Medical, Inc. · QEW · May 12, 2025 · Cardiovascular

Device Facts

• Record ID: K250421
• Device Name: InThrill™ Thrombectomy System
• Applicant: Inari Medical, Inc.
• Product Code: QEW · Cardiovascular
• Decision Date: May 12, 2025
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 870.5150
• Device Class: Class 2
• Attributes: Therapeutic

Intended Use

The InThrill™ Thrombectomy System is indicated for: • The non-surgical removal of emboli and thrombi from blood vessels, including arteriovenous fistulae and arteriovenous grafts for dialysis access, and synthetic grafts. • Injection, infusion, and/or aspiration of contrast media and other fluids into or from a blood vessel/graft. The InThrill™ Sheath is indicated for use as a conduit for the insertion of endovascular devices into the peripheral vasculature while minimizing blood loss associated with such insertions. The InThrill™ Thrombectomy System is intended for use in the peripheral vasculature. The InThrill™ Thrombectomy System is not intended for use in deep vein thrombosis (DVT) treatment.

Device Story

Single-use, over-the-wire, catheter-based system for minimally invasive peripheral thrombectomy. Comprises 8 Fr sheath and 8 Fr thrombectomy catheter. Physician inserts sheath into target vessel; expands funnel; advances catheter past thrombus. Catheter coring element deploys to engage clot via wall-to-wall contact; retracts into sheath to capture thrombus. Aspiration via syringe through sheath removes additional clot. Used in clinical settings by physicians. Benefits include non-surgical clot removal, restoring vessel patency, and minimizing blood loss during endovascular access.

Clinical Evidence

No clinical data. Substantial equivalence supported by bench testing only, including biocompatibility (ISO 10993-1), sterilization validation (ISO 11135), and comprehensive mechanical/functional verification and validation testing (e.g., tensile, torque, clot removal efficacy, radial force, and simulated use).

Technological Characteristics

8 Fr over-the-wire catheter system. Materials include Pebax (varying durometer) and braided shaft construction. Sterilized via EtO (SAL 10^-6) per ISO 11135. Mechanical sensing/actuation via manual deployment of coring element. Standalone device; no software or energy source.

Indications for Use

Indicated for non-surgical removal of emboli and thrombi from peripheral blood vessels, including arteriovenous fistulae, arteriovenous grafts for dialysis access, and synthetic grafts; also for injection, infusion, or aspiration of fluids/contrast media. Not indicated for deep vein thrombosis (DVT) treatment.

Regulatory Classification

Identification

An embolectomy catheter is a balloon-tipped catheter that is used to remove thromboemboli, i.e., blood clots which have migrated in blood vessels from one site in the vascular tree to another.

Predicate Devices

• InThrill™ Thrombectomy System (K223613)

Reference Devices

• Artix MT/Artix Thin-Walled Sheath (K241894)
• ClotTriever Thrombectomy System (K233815)
• Graft Thrombectomy Instruments (K942457)
• Cleaner Rotational Thrombectomy System (K141617)

Submission Summary (Full Text)

{0}

FDA U.S. FOOD & DRUG ADMINISTRATION

May 12, 2025

Inari Medical, Inc.
Ellen Nguyen
Senior Regulatory Affairs Specialist
6001 Oak Canyon
Suite 100
Irvine, California 92618

Re: K250421
Trade/Device Name: InThrill™ Thrombectomy System
Regulation Number: 21 CFR 870.5150
Regulation Name: Embolectomy Catheter
Regulatory Class: Class II
Product Code: QEW, KRA, DYB
Dated: February 13, 2025
Received: April 16, 2025

Dear Ellen Nguyen:

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 (the 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 available 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.

U.S. Food & Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993
www.fda.gov

{1}

K250421 - Ellen Nguyen
Page 2

Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).

Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).

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 (reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reporting-combination-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 Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.

All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/unique-device-identification-system-udi-system.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 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-devices/medical-device-safety/medical-device-reporting-mdr-how-report-medical-device-problems.

For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medical-devices/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-devices/device-advice-comprehensive-regulatory-

{2}

K250421 - Ellen Nguyen
Page 3

assistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email ([e-mail]) or phone [phone] or 301-796-7100).

Sincerely,

Digitally signed by ARIEL
G. ASH-SHAKOOR -S
Date: 2025.05.12
11:32:06 -04'00"

For
Gregory O'Connell
Assistant Director
DHT2C: Division of Coronary and
Peripheral Intervention Devices
OHT2: Office of Cardiovascular Devices
Office of Product Evaluation and Quality
Center for Devices and Radiological Health

Enclosure

{3}

FORM FDA 3881 (8/23)
Page 1 of 1
PSC Publishing Services [phone]
EF

| DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration Indications for Use | Form Approved: OMB No. 0910-0120 Expiration Date: 07/31/2026 See PRA Statement below. |
| --- | --- |
| 510(k) Number (if known) K250421 | |
| Device Name InThrill™ Thrombectomy System | |
| Indications for Use (Describe) The InThrill™ Thrombectomy System is indicated for: • The non-surgical removal of emboli and thrombi from blood vessels, including arteriovenous fistulae and arteriovenous grafts for dialysis access, and synthetic grafts. • Injection, infusion, and/or aspiration of contrast media and other fluids into or from a blood vessel/graft. The InThrill™ Sheath is indicated for use as a conduit for the insertion of endovascular devices into the peripheral vasculature while minimizing blood loss associated with such insertions. The InThrill™ Thrombectomy System is intended for use in the peripheral vasculature. The InThrill™ Thrombectomy System is not intended for use in deep vein thrombosis (DVT) treatment. | |
| Type of Use (Select one or both, as applicable) ☑ Prescription Use (Part 21 CFR 801 Subpart D) ☐ Over-The-Counter Use (21 CFR 801 Subpart C) | |
| CONTINUE ON A SEPARATE PAGE IF NEEDED. | |
| This section applies only to requirements of the Paperwork Reduction Act of 1995. *DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.* | |
| The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to: Department of Health and Human Services Food and Drug Administration Office of Chief Information Officer Paperwork Reduction Act (PRA) Staff [e-mail] | |
| "An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number." | |

{4}

K250421
PAGE 1 OF 4

# 510(K) SUMMARY

Date prepared: May 5, 2025

Name: Inari Medical, Inc.
6001 Oak Canyon, Suite 100
Irvine, CA 92618
703.347.5004

Contact person: Ellen Nguyen
Senior Regulatory Affairs Specialist

Name of Device: InThrill™ Thrombectomy System

Product code(s): QEW; KRA; DYB

Regulation: 21 CFR 870.5150 Embolectomy catheter

Regulatory class: II

Predicate device(s): Inari Medical, InThrill™ Thrombectomy System (K223613)
This device has not been subject to a design-related recall.

Reference device(s): Inari Medical, Artix MT/Artix Thin-Walled Sheath (K241894)
Inari Medical, ClotTriever Thrombectomy System (K233815)
Intramed Laboratories, Inc., Graft Thrombectomy Instruments (K942457)
Rex Medical, Cleaner Rotational Thrombectomy System (K141617)

Description:
The InThrill™ Thrombectomy System is a single-use, over-the-wire, catheter-based system for the minimally invasive treatment of thromboemboli in the peripheral vasculature, including arteriovenous fistulae and arteriovenous grafts for dialysis access, and synthetic grafts. The system comprises two main components packaged separately:
- InThrill Sheath (8 Fr)
- InThrill Thrombectomy Catheter (8 Fr)

The InThrill Sheath is placed in the target vessel, and, after its funnel is expanded, the InThrill Catheter is inserted through the sheath and advanced past the thrombus. The InThrill Catheter coring element is deployed, providing wall-to-wall contact to engage the clot, and is then retracted into the InThrill Sheath to capture the targeted thrombus. Additional clot may be removed by aspiration through the sheath with a syringe (not provided). After the procedure is complete, the InThrill Catheter and InThrill Sheath are removed from the patient.

Indications for Use:
The InThrill™ Thrombectomy System is indicated for:
- The non-surgical removal of emboli and thrombi from blood vessels, including arteriovenous fistulae and arteriovenous grafts for dialysis access, and synthetic grafts.
- Injection, infusion, and/or aspiration of contrast media and other fluids into or from a blood vessel/graft.

The InThrill™ Sheath is indicated for use as a conduit for the insertion of

{5}

K250421
PAGE 2 OF 4

endovascular devices into the peripheral vasculature while minimizing blood loss associated with such insertions.

The InThrill™ Thrombectomy System is intended for use in the peripheral vasculature.

The InThrill™ Thrombectomy System is not intended for use in deep vein thrombosis (DVT) treatment.

Summary of substantial equivalence

A tabular comparison of the predicate and subject devices is provided below:

| | Subject Device
InThrill™ Thrombectomy System | Primary Predicate
InThrill™ Thrombectomy System |
| --- | --- | --- |
| K Number | K250421 | K223613 |
| Manufacturer | Inari Medical, Inc. | Inari Medical, Inc. |
| Product Code | QEW, KRA, DYB | QEW, KRA |
| Indications for Use | The InThrill™ Thrombectomy System is indicated for:
• The non-surgical removal of emboli and thrombi from blood vessels, including arteriovenous fistulae and arteriovenous grafts for dialysis access, and synthetic grafts.
• Injection, infusion, and/or aspiration of contrast media and other fluids into or from a blood vessel/graft.

The InThrill™ Sheath is indicated for use as a conduit for the insertion of endovascular devices into the peripheral vasculature while minimizing blood loss associated with such insertions.

The InThrill™ Thrombectomy System is intended for use in the peripheral vasculature.

The InThrill™ Thrombectomy System is not intended for use in deep vein thrombosis (DVT) treatment. | The InThrill™ Thrombectomy System is indicated for:
• The non-surgical removal of emboli and thrombi from blood vessels, including arteriovenous fistulae and arteriovenous grafts for dialysis access, and synthetic grafts.
• Injection, infusion, and/or aspiration of contrast media and other fluids into or from a blood vessel/graft.

The InThrill™ Thrombectomy System is intended for use in the peripheral vasculature.

The InThrill™ Thrombectomy System is not intended for use in deep vein thrombosis (DVT) treatment. |
| Sterility | Same | SAL 10^{-6}, EO |
| Shelf-life | 6 months | 2 years |
| Guidewire compatibility | Same | 0.035” |

{6}

K250421
PAGE 3 OF 4

| Device dimensions | Same except for a longer sheath tip taper and changes to coring element (longer length, smaller diameter, and change to geometry) | Appropriately sized for the target vessel treatment range |
| --- | --- | --- |
| Device and packaging materials | Same with decreased Pebax durometer at sheath shaft tip, increased Pebax durometer at catheter shaft tip, and change from two coaxial braided shaft to a single, thicker shaft | Biocompatible, commonly used materials for medical devices |
| Accessories provided | Dilator, pre-dilator, element support tool | Dilator, pre-dilator |

Summary of substantial equivalence

## Biocompatibility

The following biocompatibility tests were completed for the subject device:

- Cytotoxicity
- Intracutaneous Reactivity
- Material-Mediated Pyrogenicity
- Hemocompatibility (Hemolysis, Complement Activation)

- Sensitization
- Acute Systemic Toxicity
- Thromboresistance (Platelet and Leukocyte Count, Partial Thromboplastin Time, and Anticoagulated Venous Implant Study)

The passing results demonstrate that the subject device and accessories meet biological safety requirements per ISO 10993-1.

## Sterilization

The subject device, including its accessories, is sterilized using EtO to achieve a sterility assurance level (SAL) of $10^{-6}$ using a validated sterilization process in accordance with the principles of ISO 11135:2014/Amd 1:2018 and AAMI TIR 28:2016.

## Non-Clinical Testing

In accordance with the Design Failure Modes and Effects Analysis, verification and validation testing were identified to support the substantial equivalence of the InThrill™ Thrombectomy System to the predicate device. These tests included:

## Performance Tests

**Catheter - Verification:**

- Visual & Dimensional
- Guidewire Compatibility
- Hemostasis
- Conditioning
- Post-conditioning Hemostasis – Sheath
- Tensile
- Corrosion
- Torque (Characterization)

{7}

K250421
PAGE 4 OF 4

## System – Validation:
- Catheter Luer Connections
- Catheter Insertion and Retraction
- Device Indicators
- Sheath Funnel Wall Apposition
- Clot Burden Removal Efficacy
- Device Deployment
- Visual Inspections

## Sheath - Verification:
- Visual & Dimensional
- Fluid Leakage (Pre- and Post-Conditioning)
- Air Leakage (Pre- and Post-Conditioning)
- Vacuum Testing (Pre- and Post-Conditioning)
- Simulated Use
- Retraction with Clot Analog
- Tensile
- Torque

## System – Verification:
- Radial Force (Characterization)
- Pressure (Characterization)
- Graft Abrasion
- Graft Leak
- Conditioning (In-Graft Full System and Vein-to-Graft Anastomosis)
- Comparative Thrombectomy (Characterization)

Test results demonstrated that all acceptance criteria were met; therefore, the device conforms to established product specifications.

Animal testing was not required for the determination of substantial equivalence.

Clinical testing was not required for the determination of substantial equivalence.

## Conclusion

The InThrill™ Thrombectomy System has the same intended use and principles of operation as the predicate. Non-clinical performance data show that the different technological characteristics between the devices do not raise any new or different questions of safety or effectiveness and support the InThrill™ Thrombectomy System’s substantial equivalence to the predicate device.