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510(k) Data Aggregation
(280 days)
The WallFlex Biliary RX Fully Covered Stent System RMV is indicated for indwell up to 12 months in the treatment of benign biliary strictures secondary to chronic pancreatitis.
The WallFlex Biliary RX Fully Covered Stent System RMV consists of 2 components: the implantable fully covered self-expanding metallic biliary stent (FC-SEMBS) and the Rapid Exchange (RX) delivery device. The FC-SEMBS is made out of Nitinol monofilament wire with a radiopaque platinum core, braided in a tubular mesh configuration. The stent has proximal and distal flares at each end to aid in preventing migration. The proximal flare also contains the biliary stent retrieval loop. The biliary stent is covered with a Permalume™ silicone covering along its entire length except for 2 mm on the retrieval loop end. The RX delivery device is a coaxial tube design. The exterior tube is used to constrain the biliary stent before deployment and re-constrain the biliary stent, if biliary stent repositioning is necessary, after partial deployment. The exterior tube has a clear section so that the constrained stent is visible. A yellow transition zone on the inner tube of the delivery system is visible between the stent and the blue outer sheath. There are four radiopaque (RO) markers to aid in the deployment of the stent while using fluoroscopy. There are two RO markers on the inner tube of the delivery system identifying the ends of the constrained biliary stent. Between these RO markers is an additional RO marker that indicates at what point re-constrainment is no longer possible. The fourth RO marker at the leading end of the exterior tube indicates how far the biliary stent has been deployed. There is one visual marker on the interior tube between the handles to aid in the deployment of the biliary stent. The visual marker indicates the point at which re-constrainment is no longer possible. The interior tube has a single central lumen to accommodate a 0.035 inch (0.86 mm) guidewire.
The provided text describes the WallFlex Biliary RX Fully Covered Stent System RMV, its design, nonclinical/bench studies, and a clinical study conducted to assess its safety and effectiveness.
Here's a breakdown of the acceptance criteria and study details:
1. Table of Acceptance Criteria & Reported Device Performance
The acceptance criteria are primarily derived from the "Special Controls" section and the "Summary of Nonclinical Studies" (Table 2). The reported device performance is extracted from the "Summary of Nonclinical/Bench Studies" section and the "Results" section of the clinical study.
| Acceptance Criteria Category | Specific Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Sterilization | The sterility assurance level (SAL) shall be 10-6. | Passed: Sterilization was re-assessed in 2015 to ensure compliance to most recent version of ANSI/AAMI/ISO 10993-7. Testing was conducted on the 10x120mm fully covered stent, considered worst-case. |
| Ethylene Oxide Residuals | EtOH residual amounts are below the maximum amount allowed: For the stent, the average daily dose of EO to patient shall not exceed 0.1 mg/day, max EO dose of 20 mg in first 24 hr, 60 mg in first 30 days, 2.5 g in a lifetime. For the delivery catheter, the average daily dose shall not exceed 4 mg. | Passed: EtOH residual amounts are below the maximum amount allowed. |
| Biocompatibility | Cytotoxicity: Grade 0 (non-cytotoxic); Irritation: Non-irritant (based on histopathologic evaluations); Sensitization: No signs of sensitization from polar and non-polar extracts; Acute Systemic Toxicity: No evidence of mortality or systemic toxicity; Genotoxicity: Non-mutagenic; Implantation: Non-irritant (based on histopathologic evaluations); Subchronic Toxicity: No signs of systemic toxicity due to leachable components; Nickel leaching: Acceptable resistance to corrosion and acceptable nickel leach rates; Toxicological Risk: Not likely to lead to systemic toxicity. | Passed: Cytotoxicity Grade 0. Irritation non-irritant. No signs of sensitization. No evidence of mortality or systemic toxicity. Non-mutagenic. Non-irritant after implantation. No signs of systemic toxicity. Acceptable nickel leaching demonstrated. Exposure to the stent is not likely to lead to systemic toxicity. |
| Deployment Testing | The delivery catheter must safely and accurately deliver the stent to the intended anatomic location. No damage to the stent or simulated stricture model should occur. | Passed: Stent sizes tested represent the smallest and largest sizes available and can be used as surrogates. The stent was successfully placed in 100% (127/127) of patients in the clinical study. |
| Expansion/Compression Force Testing | Radial expansion forces must be at least 85% of specified N values for various stent diameters and compressions. Radial compression forces must be at least 85% of specified N values for various stent diameters and compressions. | Passed: The device met the specified radial expansion and compression forces. |
| Dimensional Testing | All dimensions should be within design tolerance ranges. | Passed: Dimensions of each stent size and delivery catheter were measured and verified to meet the acceptance criteria and labeled dimensions. |
| Tensile Strength Testing (Bond Integrity) | All bonded components of the delivery catheter should withstand forces that exceed those encountered during clinical use. | Passed: Bonded joints of delivery catheters were tested to failure and withstood forces exceeding those encountered clinically. |
| Stent Integrity | No crevice or pitting corrosion; No more than 2 weld breaks; No significant weight loss; Meet specification for radial compression and expansion forces; Wire must meet specification for tensile properties; Stent cover integrity must meet requirements for holes and delamination. | Passed: Stents tested represent worst-case scenario. No degradation observed. |
| MRI Compatibility | MRI compatibility labeling must be supported by testing. Displacement forces should not damage tissue, and localized temperature increases should not damage tissues when patients are scanned as outlined in the labeling. | Evaluated: Mean deflection angle of 3°. Worst case projected temperature rise of 5.5°C for whole body average SAR of 4 W/kg. Artifacts appeared as localized signal voids extending ~10 mm from stent wall perimeter and ~2mm beyond each end. This data supports the MRI Conditional labeling. |
| Shelf Life (Package Integrity) | Packaging must not be compromised below a minimum pressure threshold. No channels, pinholes, or other barrier breaches allowed. All samples must not have channels visible at 10X magnification. | Passed: Package integrity testing demonstrated maintenance of sterility. |
| Shelf Life (Functional Performance) | Deployment Testing: Delivery catheter should safely and reliably deliver the stent to the intended location without damage to the stent or patient after 25 months real time aging. Expansion/Compression Force Testing: Forces must not be impacted by aging. Flexural Rigidity: Stents must not become rigid after aging. Covering Material Integrity: Maximum of 6 diamonds containing compromised coating integrity. Weld Integrity: No more than two broken wire weld joints observed. Tensile Strength: Bonded components withstand forces after aging. | Passed: Deployment testing passed with largest stent size after aging. Expansion/compression forces passed after aging. Flexural rigidity passed after aging. Covering material integrity passed (maximum 6 diamonds with compromised coating). Weld integrity passed (no more than 2 broken welds). Tensile strength testing passed after aging. |
| Clinical Performance (Removal) | The ability to safely place and subsequently remove the stent after the maximum labeled indwell period. | Stent Removability: 72.4% (92/127) ITT, 78.0% (92/118) PP. Removal Success: 84.3% (107/127) ITT, 90.7% (107/118) PP. Stent indwell up to 613 days (~20 months). |
| Clinical Performance (Functionality) | The stent resolves strictures during the maximum labeled indwell period. | Stent Functionality During Stent Indwell: 77.2% (98/127) ITT, 83.1% (98/118) PP (lack of required reintervention). Stricture Resolution: 74.0% (94/127) ITT, 79.7% (94/118) PP (lack of stricture-related re-intervention). Biliary obstructive symptoms reduced from 51.2% (baseline) to 6.3% (Indwell month 6). Bilirubin and alkaline phosphatase levels decreased. |
| Clinical Performance (Recurrence) | Stricture resolution is maintained post-stent removal. | No Stricture Recurrence: 85.1% (80/94) ITT/PP patients who initially achieved stricture resolution did not experience recurrence over median 19.0 months follow-up. |
| Clinical Performance (Adverse Events) | All adverse event data including bile duct obstruction and trauma to the bile duct should be reported. | SAEs (patients with at least one SAE): 36.2% (46/127) ITT, 36.4% (43/118) PP. Common SAEs: Pancreatitis (16%), Cholangitis (9%). No stent or stent removal related deaths. |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Clinical Study (Test Set): 127 patients for the Intent-to-Treat (ITT) cohort, and 118 patients for the Per-Protocol (PP) cohort.
- Data Provenance:
- Country of Origin: The clinical study was a "large prospective multinational study utilizing 13 centers in 11 countries outside of the US (OUS)." Specific countries are not listed, but it indicates a broad international representation.
- Retrospective/Prospective: The clinical study was explicitly prospective.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications of those Experts
The document does not specify the number or qualifications of experts establishing ground truth for the clinical study directly. The "ground truth" for clinical outcomes (e.g., stricture resolution, stent removability, adverse events) would have been established by the clinical investigators at the 13 centers based on patient follow-up, medical records, imaging, and endoscopic findings. These would be qualified medical professionals (e.g., gastroenterologists, interventional radiologists) involved in the care of the patients and the conduct of the trial. However, no specific details on their number or specific qualifications (e.g., "radiologist with 10 years of experience") are provided within this document.
4. Adjudication Method for the Test Set
The document does not explicitly describe an adjudication method (e.g., 2+1, 3+1) for establishing clinical outcomes. Clinical outcomes would likely have been determined based on predefined criteria in the study protocol and assessed by the attending clinicians at each site. Serious adverse events (SAEs) were reported and summarized, indicating a system for tracking and categorizing these events, but not explicitly an independent adjudication panel.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No, an MRMC comparative effectiveness study involving human readers improving with AI vs. without AI assistance was not done. This device is a medical stent, not an AI diagnostic tool, so such a study would not be applicable. The clinical study assessed the device's performance directly in patients.
6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study
No, a standalone (algorithm only) study was not done. This device is a physical medical device (stent system) that requires human intervention (endoscopic placement and removal). Its performance is inherently linked to human use in a clinical setting.
7. Type of Ground Truth Used
The ground truth for the clinical study was based on clinical outcomes data from patients, including:
- Endoscopic findings (stent placement, removability, removal success)
- Patient symptoms (biliary obstructive symptoms)
- Laboratory test results (bilirubin, alkaline phosphatase levels)
- Medical records (re-interventions, recurrence, adverse events, surgical outcomes)
For the non-clinical/bench studies, the ground truth was established through engineering and laboratory test standards, specifications, and physical measurements (e.g., ISO, ASTM standards, pre-defined tolerance ranges, visual inspections, mechanical testing).
8. Sample Size for the Training Set
The document describes a single prospective clinical study acting as the primary evidence for the device's clinical performance. It does not mention a separate "training set" in the context of machine learning or AI models. This is a traditional medical device submission, not an AI/ML device.
9. How the Ground Truth for the Training Set Was Established
As there is no "training set" in the context of an AI/ML model for this traditional medical device, this question is not applicable. The clinical study data was used to demonstrate the device's safety and effectiveness directly, not to train an algorithm.
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(74 days)
The WallFlex™ Biliary RX Stent System Uncovered, WallFlex™ Biliary RX Stent System Partially Covered, and WallFlex™ Biliary RX Stent System Fully Covered are indicated for use in the palliative treatment of biliary strictures produced by malignant neoplasms.
The WallFlex™ Biliary RX Stent System Uncovered, WallFlex™ Biliary RX Stent System Partially Covered, and WallFlex 114 Biliary RX Stent System Fully Covered consist of a flexible delivery system preloaded with a self-expanding biliary metal stent.
The stent is offered uncovered or covered. The covered stents are offered as fully covered, or partially covered with a Permalume™ stent covering. The stent wires have a radiopaque core to improve radiopacity.
The stent is preloaded onto the delivery system. which has radiopaque marker bands used to aid in imaging during deployment of the stent. The delivery system accommodates a 0.035 in (0.89 mm) guidewire.
The provided text is a 510(k) summary for the WallFlex™ Biliary RX Stent System, which is a medical device. This document does not describe the acceptance criteria and a study proving a device meets those criteria in the context of an Artificial Intelligence (AI) or software-as-a-medical-device (SaMD) study.
Instead, this document focuses on the substantial equivalence of the WallFlex™ Biliary RX Stent System to its predicate devices for a specific labeling claim regarding MR Conditional safety and compatibility. The performance data mentioned is for in-vitro testing on the biliary metal stent, which is typical for hardware medical devices, not AI/SaMD.
Therefore, I cannot extract the requested information (acceptance criteria, device performance, sample sizes for test/training sets, data provenance, number of experts, adjudication methods, MRMC studies, standalone performance, or ground truth types) because the provided text does not describe an AI/SaMD study. It's a regulatory submission for a physical medical device.
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