(15 days)
The IMPRA ePTFE Arteriovenous Cuffed Graft is indicated for use as a subcutaneous arteriovenous conduit for blood access.
The IMPRA ePTFE Arteriovenous Cuffed Graft is an expanded polytetrafluoroethylene angioaccess graft [i.e., an IMPRA ePTFE Vascular Graft, the predicate device for this 510(k)] with a modified venous end. The venous end is cuffed, facilitating vessel conformity, a uniform suturing surface, and improved flow through the anastomosis. The IMPRA ePTFE Arteriovenous Cuffed Graft is made from the same materials as the predicate device, i.e., polytetrafluoroethylene (PTFE), lubricant used as a manufacturing aid, a blue pigment used in the orientation lines, and the external support PTFE beading. These grafts are supplied in the same product configurations as the predicate device (straight, stepped, CenterFlex, and stepped CenterFlex), and are packaged, labeled, and sterilized in the same manner as the predicate device.
The provided text outlines the safety and effectiveness of the IMPRA ePTFE Arteriovenous Cuffed Graft, primarily through comparison to a predicate device (IMPRA ePTFE Vascular Graft) and a similar "AVP" device used in a clinical study. However, it does not describe an AI/ML-based device, nor does it present acceptance criteria or a study design in the way an AI/ML product would.
Based on the provided text, I cannot answer questions related to AI/ML device performance, acceptance criteria, test sets, ground truth establishment, or expert involvement as these concepts are not applicable to the medical device described (a vascular graft).
The document focuses on demonstrating substantial equivalence to an existing predicate device, a common pathway for medical device clearance. The "performance" discussed relates to the biological and mechanical performance of the graft itself, not the performance of an AI algorithm.
Therefore, I will extract relevant information about the device's assessment from the provided text, rephrasing the "acceptance criteria" and "study" in the context of a non-AI medical device.
Here's the information parsed from the document, tailored as much as possible to your requested format, but with strong caveats that it's not an AI/ML device:
Device Under Evaluation: IMPRA ePTFE Arteriovenous Cuffed Graft
This document describes a non-AI medical device (a vascular graft). Therefore, many of the requested categories related to AI/ML performance, test sets, ground truth, and expert adjudication are not directly applicable. I will provide information relevant to the device's assessment from the text, interpreting "acceptance criteria" in the context of device performance and safety.
1. Table of Acceptance Criteria and Reported Device Performance
The "acceptance criteria" for this device are primarily based on demonstrating substantial equivalence to a predicate device (IMPRA ePTFE Vascular Graft) and acceptable performance in animal and clinical studies.
| Category | Acceptance Criteria (Implied for Substantial Equivalence and Safety) | Reported Device Performance (IMPRA ePTFE Arteriovenous Cuffed Graft) |
|---|---|---|
| Material | Same materials as predicate device, biocompatible. | Made from same materials: polytetrafluoroethylene (PTFE), lubricant, blue pigment, external support PTFE beading. Biocompatibility (via predicate and cytotoxicity tests) confirmed. |
| Sterilization | Validated sterilization process. | Sterilized with 100% Ethylene Oxide using the overkill method, single-use, but resterilization with steam is validated in Directions for Use. |
| Physical Properties | Meets standards (e.g., ANSI/AAMI VP20 - 1994) and FDA guidance for vascular prostheses, suitable for intended use, strength not compromised by modifications. | Passed testing per ANSI/AAMI VP20 - 1994 and 1993 FDA Draft Guidance. Significant reduction in wall thickness at cuff does not compromise strength (longitudinal, burst, suture retention). |
| Handling | Equivalent or superior handling characteristics compared to predicate. | Animal study showed "performed better, overall" in handling characteristics (needle penetration difficulty, suture drag, suture hole bleeding) compared to predicate. |
| Intimal Hyperplasia | Reduced or comparable intimal hyperplasia formation, indicating improved patency. | Animal study showed: Less intimal area and lower percentage of stenosed area at the venous end (not statistically significant). Statistically significant 50% less average intimal thickness in the toe regions compared to predicate. Concluded to decrease intimal hyperplasia, potentially leading to decreased failure rate and longer patency. |
| Thrombosis Rate | Acceptable or improved thrombosis rate compared to conventional grafts. | Clinical study (with AVP device, similar cuffed design): Overall thrombosis rate of 5.2% for cuffed grafts vs. 16% for conventional grafts. |
| Patency | Acceptable or improved patency rates. | Clinical study (with AVP device): Cumulative primary patencies of 88% at 45 months for AVP grafts vs. 66% at 27 months for conventional prostheses (control). Mean duration of shunt function was comparable. |
| Complications/Safety | No adverse effect on safety (complications) or efficacy (patency); comparable complication rates (excluding thrombosis which was better). No device contribution to patient deaths. | Clinical study (with AVP device): Complications comparable except for thrombosis rate (AVP better) and death rate (AVP 21.8% vs. conventional 12%). Death rate difference attributed to patient comorbidities, not the device. Concluded clinical implantation of AVP graft did not adversely affect safety (complications) or efficacy (patency). |
| Design Differences | Design modifications do not raise new questions of safety or effectiveness. | Cuffed portion is the only technological difference from predicate. Manufacturing process for cuff (one-piece ePTFE) differs from AVP (two ePTFE pieces sutured). This difference in wall thickness (thinner in cuffed graft) does not compromise safety or strength. Demonstrated substantial equivalence. |
2. Sample Size Used for the Test Set and Data Provenance
- Animal Study: The text mentions "eight sheep" were implanted with grafts for the handling assessment. It doesn't specify if the "morphometric analysis" used the same eight or a different number, or how many grafts were implanted per sheep.
- Clinical Study (AVP Graft):
- Test Set (Cuffed Grafts): 174 AVP grafts (constructed from standard 4mm-7mm Stepped IMPRA ePTFE grafts)
- Control Set (Conventional Grafts): 50 conventional 4mm-7mm Stepped IMPRA ePTFE grafts
- Data Provenance: Retrospective for some aspects, but described as patients "entered into this study." All clinical procedures were performed at the Charite Hospital, Berlin, Germany. Between August 1992 to June 1996.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
This question is not applicable as this is a physical medical device, not an AI/ML system requiring expert ground truth for classification or detection.
For the clinical study, the "ground truth" was established by direct clinical observation of patient outcomes:
- Surgical procedures, implantation, and immediate postoperative development were observed.
- Follow-up observations were conducted at intervals of six months, up to the second year.
- Outcomes like patency, thrombosis, other complications, and patient deaths were recorded.
- The study was designed and conducted by Dr. Hans Scholz, Chief of Vascular Surgery, Queen Elisabeth Hospital, Berlin, who was also the inventor of the AVP device. His qualifications (Chief of Vascular Surgery) imply expert medical assessment.
4. Adjudication Method for the Test Set
This question is not applicable. Clinical outcomes were directly observed and recorded by the medical team involved in the study under the direction of Dr. Scholz. There's no mention of an "adjudication method" in the sense of resolving disagreements among multiple experts for a test set, as would be relevant for an AI/ML study.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC study was not done. This type of study is specific to evaluating diagnostic devices, often involving multiple human readers assessing cases with and without AI assistance. This document describes a vascular graft.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) Was Done
No. This concept is not applicable as the device is a physical vascular graft, not an algorithm.
7. The Type of Ground Truth Used
- Animal Study: Histological analysis (to determine thickness of intimal hyperplasia, degree of luminal narrowing, and cellular characterization), photographs of grafts and adjacent vessels at explant, and direct observation of handling characteristics.
- Clinical Study (AVP Graft): Outcomes data from direct patient observation and follow-up, including:
- Patency rates (cumulative primary patencies)
- Thrombosis rates
- Complication rates
- Mortality rates and causes of death (patient characteristics and comorbidities factored in for death analysis).
- Flow rates through the shunt (between selected patients).
8. The Sample Size for the Training Set
This question is not applicable. There is no AI/ML "training set" for this physical medical device. The "training" for such devices typically involves extensive engineering design, material science, bench testing, and animal studies to refine the product before human clinical trials.
9. How the Ground Truth for the Training Set Was Established
This question is not applicable, as there is no AI/ML training set. The "ground truth" for developing this device was established through standard engineering principles, materials science, preclinical (bench and animal) testing, and prior clinical experience with similar devices (the predicate device and the AVP).
§ 870.3450 Vascular graft prosthesis.
(a)
Identification. A vascular graft prosthesis is an implanted device intended to repair, replace, or bypass sections of native or artificial vessels, excluding coronary or cerebral vasculature, and to provide vascular access. It is commonly constructed of materials such as polyethylene terephthalate and polytetrafluoroethylene, and it may be coated with a biological coating, such as albumin or collagen, or a synthetic coating, such as silicone. The graft structure itself is not made of materials of animal origin, including human umbilical cords.(b)
Classification. Class II (special controls). The special control for this device is the FDA guidance document entitled “Guidance Document for Vascular Prostheses 510(k) Submissions.”