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The AXIOS™ Stent and Delivery System is indicated for use to facilitate transenteric endoscopic drainage of symptomatic pancreatic pseudocysts ≥ 6cm in size, with ≥ 70% fluid content that are adherent to the gastric or bowel wall. Once placed, the AXIOS Stent functions as an access port allowing passage of standard and therapeutic endoscopes to facilitate debridement, irrigation and cystoscopy. The stent is intended for implantation up to 60 days and should be removed upon confirmation of pseudocyst resolution.

The AXIOS™ Stent and Delivery System is an endoscopic device designed to deliver a fully-covered stent between a pancreatic pseudocyst and the gastrointestinal tract. The AXIOS™ Stent is a flexible, MR compatible, fully-covered self-expanding Nitinol stent preloaded within the AXIOS Delivery System. The AXIOS™ Delivery System is compatible with endoscopes equipped with a 3.7mm diameter or larger working channel. The AXIOS Stent and Delivery System is provided sterile, disposable and intended for use during a single patient procedure. The AXIOS Stent and Delivery System are sterilized by a validated method of sterilization via Ethylene Oxide (EO).

The provided document is limited to a 510(k) summary for the AXIOS™ Stent and Delivery System. This type of submission focuses on demonstrating substantial equivalence to a predicate device through non-clinical testing rather than detailed clinical studies with acceptance criteria, performance metrics, and human reader evaluations typical for AI/ML-based diagnostic devices.

Therefore, the information required to populate most of the sections of your request (acceptance criteria, detailed study design with sample sizes for test/training sets, expert qualifications, adjudication methods, MRMC studies, standalone performance, and ground truth establishment for AI/ML models) is not present in this document.

However, I can extract information related to non-clinical testing and the overall conclusion about device performance:

1. Table of Acceptance Criteria and Reported Device Performance:

2. Sample size used for the test set and the data provenance (e.g., country of origin of the data, retrospective or prospective)

• Not Applicable. This document describes non-clinical bench testing and biocompatibility testing, not human clinical trials or AI/ML model performance evaluation with test sets derived from patient data.

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)

• Not Applicable. Ground truth, in the context of expert consensus for AI/ML, is not relevant to this type of device submission. The "ground truth" here is implied by predefined engineering specifications and regulatory standards met through non-clinical laboratory testing.

4. Adjudication method (e.g., 2+1, 3+1, none) for the test set

• Not Applicable. Adjudication methods are typically for clinical outcome or diagnostic agreement, which is not described for this non-clinical submission.

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

• No. An MRMC study is not mentioned as this is a medical device for drainage, not an AI-based diagnostic tool.

6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done

• No. This is a hardware medical device; the concept of "standalone algorithm performance" does not apply.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)

• For the non-clinical testing, the "ground truth" was established by predetermined product specifications, performance characteristics, regulatory standards, and recognized consensus standards (e.g., for biocompatibility and sterilization). The direct comparison was against the predicate device (AXIOS™ Stent and Delivery System K123250) for substantial equivalence.

8. The sample size for the training set

• Not Applicable. This document does not pertain to an AI/ML device that requires a training set.

9. How the ground truth for the training set was established

• Not Applicable. As above, no training set for an AI/ML model is described.

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The AXIOS Stent and Delivery System is indicated for use to facilitate transgastric or transduodenal endoscopic drainage of symptomatic pancreatic pseudocysts ≥ 6 cm in size, with ≥ 70% fluid content that are adherent to the bowel wall. Once placed, the AXIOS Stent functions as a port allowing passage of standard and therapeutic endoscopes to facilitate debridement, irrigation and cystoscopy. The stent is intended for implantation up to 60 days and should be removed upon confirmation of pseudocyst resolution.

The AXIOS Stent and Delivery System consists of two major components, the catheter-based delivery system and the implantable stent. The stent is a flexible, fully-covered. self-expanding Nitinol stent, which is preloaded within the catheter-based delivery system. The system is intended to cannulate the transgastric or transduodenal wall into a pancreatic pseudocyst for endoscopic drainage. The stent serves as a conduit for passive drainage of pseudocyst contents directly into the GI tract. The large lumen diameter provides a short path and may allow secure access to the pseudocyst interior for additional diagnostic or therapeutic procedures. The AXIOS Stent is designed with a duplicate "anchor" or "flange" on each end to achieve tissue apposition and prevent migration. The stent is radiopaque and is fully covered with silicone to prevent leakage, minimize tissue in-growth, and facilitate removal. The AXIOS Stent will be provided in two lumen diameters (10mm and 15mm) and one length (10mm). The AXIOS Delivery System consists of a catheter and an integrated handle with manual controls for positioning and deploying the AXIOS stent. The AXIOS Delivery System is sized to fit within commercially available echoendoscopes with a working channel of 3.7 mm diameter or larger. The Delivery System catheter is 138 cm in working length and attached directly to the endoscope handle. The AXIOS Delivery System requires an access site of at least 10 Fr. The AXIOS Stent and Delivery System is provided sterile, disposable and intended for use during a single patient procedure.

Acceptance Criteria and Device Performance for the AXIOS Stent and Delivery System

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for the AXIOS Stent and Delivery System were primarily drawn from the "Safety Endpoints" and "Effectiveness Endpoints" sections of the pivotal clinical study.

2. Sample Size Used for the Test Set and Data Provenance

• Sample Size for Test Set:
  • Pivotal Study (effectiveness and safety): 33 subjects enrolled (Intent-to-Treat, ITT).
  • Modified Intent-to-Treat (mITT): 30 subjects (received an AXIOS stent).
  • Per-Protocol (PP): 29 subjects (received an AXIOS stent and had an evaluable clinical outcome). The effectiveness endpoints were evaluated on the ITT (technical success) and PP (patency, removability, clinical success, overall effectiveness) populations. Safety endpoints were evaluated on both ITT and PP populations.
• Data Provenance: The pivotal study was a prospective, multi-center, single-arm study conducted under an IDE (Investigational Device Exemption). The specific countries of origin are not mentioned, but "multi-center" implies multiple study sites. There was also a feasibility study that was a retrospective case series conducted at a single site, Tokyo Medical University.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of those Experts

The document does not explicitly state the number of experts used to establish ground truth for the test set or their specific qualifications (e.g., "radiologist with 10 years of experience").

• Clinical Study Setting: The "Pivotal" study was a multi-center study, meaning several physicians (likely gastroenterologists or surgeons specializing in endoscopic procedures) at different sites were involved in patient selection, procedures, and outcome assessment.
• Radiographic Analysis: "Clinical success, defined as at least a 50% decrease in pseudocyst size, based on radiographic analysis," indicates that imaging experts (radiologists) were involved in evaluating pseudocyst resolution. However, the exact number, their role in establishing ground truth (e.g., independent adjudication), or their specific qualifications are not detailed.

4. Adjudication Method for the Test Set

The document does not explicitly detail a formal adjudication method (e.g., 2+1, 3+1) for the clinical outcomes.

• Pivotal Study Design: It was a prospective, single-arm study where outcomes were assessed as part of the standard clinical trial procedure at various time points (30-day, 60-day, 3 and 6 months post-removal).
• Radiographic Interpretation: Clinical success was based on "radiographic analysis." While this implies interpretation by experts, there's no mention of a blinded, independent central review or a consensus-based adjudication process for these radiographic assessments. The interpretation likely occurred at each study site.

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

• No MRMC Study: A Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not conducted. This device is a medical implant (stent) and its delivery system, not an AI-powered diagnostic or assistive tool. Therefore, the concept of "human readers improve with AI vs. without AI assistance" is not applicable in this context.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done

• Not Applicable: This device is a physical medical device (stent and delivery system), not an algorithm or AI product. Therefore, standalone algorithm performance is not relevant or applicable.

7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)

The ground truth for the clinical study was primarily based on:

• Clinical Outcomes Data: This includes direct measurements and observations from the intervention and follow-up, such as:
  • Radiographic Analysis: Pseudocyst size reduction (e.g., ≥50% decrease) based on imaging (CT, ultrasound, MRI, EUS).
  • Direct Observation during Endoscopy: Stent placement, patency, successful removal, and presence of tissue injury.
  • Patient Symptoms and Adverse Events: Documented by clinical staff at study sites.
  • Pathology: Histopathological evaluation was performed in the animal study, but it's not explicitly stated as the primary ground truth for human clinical outcomes.

8. The Sample Size for the Training Set

• No Training Set (for an algorithm): Since this is a physical medical device and not an AI algorithm, there was no separate "training set" in the context of machine learning. The "training" for the device's design and manufacture would involve engineering principles, bench testing data, and animal studies prior to human use.
• Feasibility Study as preliminary data: A non-randomized feasibility clinical study was conducted with 15 subjects prior to the pivotal study. This could be considered as preliminary human data informing the design and protocol for the larger pivotal study, but not a "training set" for an algorithm.

9. How the Ground Truth for the Training Set Was Established

• Not Applicable (no training set for an algorithm): As clarified above, there was no machine learning "training set" for an algorithm.
• Ground Truth for Pre-Clinical and Feasibility Data:
  • Animal Study: Ground truth for the animal study was established through direct observation during procedures, subsequent endoscopic evaluations, and histopathological evaluation post-euthanasia.
  • Feasibility Study: For the 15-subject feasibility study, ground truth was based on clinical assessment of technical success (deployment, implantation, removal) and clinical success (pseudocyst resolution) via follow-up visits and likely imaging. Methods were similar to those used in the pivotal study.

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