(73 days)
IMPRA Carboflo™ ePTFE Vascular Grafts are intended for use as vascular prostheses.
IMPRA Carboflo™ ePTFE Vascular Grafts are made primarily of expanded polytetrafluoroethylene (ePTFE) using the same manufacturing procedures that are used to manufacture IMPRA ePTFE Vascular Grafts, the devices to which substantial equivalence is claimed. The region of the graft wall adjacent to the lumen, approximately 20-25% of the total wall thickness, is uniformly impregnated with Carbon particles along the entire length of the carbon impregnated region is formed integral to the outer region of the wall by mixing the PTFE resin mixed with carbon particles, with the non-carbon containing PTFE resin during a singular extrusion process, which results in a monolithic graft wall. The carbon used in the device is USP grade activated charcoal. All other components of the Carboflo graft, namely PTFE, lubricant used as a manufacturing aid, blue pigment incorporated in the orientation lines, and the external support PTFE beading are the same as those used in the manufacture of the predicate devices. These grafts are supplied in the same product configurations as the predicate device, and are packaged, labeled, and sterilized in the same manner as the predicate devices.
Here's a breakdown of the acceptance criteria and the study that proves the device meets them, based on the provided text:
Acceptance Criteria and Device Performance
The document states that the "acceptance criteria for both the new device and predicate devices are the same." However, it does not explicitly list these criteria in a table. Instead, it details comparative performance with a predicate device. Based on the "Comparison of the Device Characteristics to the Predicate" section, the implicit acceptance criteria are related to:
- Physical Properties: The device should not have its physical properties negatively affected by the addition of carbon particles and should be comparable to the predicate.
- Thrombus Free Surface Area: The device should demonstrate at least equivalent or improved thrombus-free surface area compared to the predicate in short-term studies.
- Platelet Accumulation: The device should show at least equivalent or reduced platelet accumulation compared to the predicate in short-term studies.
- Patency (Primary and Secondary): The device's patency rates should be comparable to or better than the predicate device.
- Adverse Events: The device should not introduce new types of complications and the overall complication profile should be comparable to the predicate.
Given this, the table of acceptance criteria and reported device performance is inferred as follows:
| Acceptance Criteria Category | Specific Criteria (Inferred) | Reported Device Performance (IMPRA Carboflo™ ePTFE Vascular Graft) |
|---|---|---|
| Physical and Mechanical Properties | Addition of carbon particles should not affect physical properties. Comparable to predicate in bench testing (e.g., repeated puncture, particulate flow). | "Testing of a variety of product types shows that the addition of carbon particles into the graft wall did not affect the physical properties of the Carboflo grafts. Both the new device and predicate device undergo the same testing and evaluation procedures. The acceptance criteria for both the new device and predicate devices are the same." |
| "Additional bench testing performed to determine the response of the Carboflo ePTFE graft compared to the Standard ePTFE in repeated puncture test and the particulate flow test showed them to be equivalent." | ||
| Thrombogenicity (Pre-clinical) | Significantly higher Thrombus Free Surface Area compared to predicate (long-term animal studies). Reduced platelet accumulation compared to predicate (short-term animal studies). | "Animal studies comparing the Carboflo grafts with Standard IMPRA ePTFE grafts have shown that the inside surfaces of the Carboflo grafts have a significantly higher Thrombus Free Surface Area after 3 months." |
| "Short-term animal studies in dogs and rabbits have shown that the Carboflo inside surfaces have reduced platelet accumulation when compared to Standard ePTFE vascular grafts, suggesting that the addition of carbon particles reduces the thrombogenicity of the surface." | ||
| Clinical Patency (Primary - 24 months) | Primary Patency rate should be comparable to or better than the predicate. | "Cumulative Primary Patency for Carboflo grafts was 36.8 % compared to 27.7% for Standard grafts at the end of 24 months. These results are not statistically significantly different at p=0.05." (Indicates comparable, though numerically higher) |
| Clinical Patency (Secondary - 24 months) | Secondary Patency rate should be comparable to or better than the predicate. | "Cumulative Secondary Patency for Carboflo grafts was 42.7% compared to 32.3% for Standard grafts. These results are not statistically significantly different at p=0.05." (Indicates comparable, though numerically higher) |
| Device Safety / Complications (Clinical) | No new types of complications identified. Overall complication profile (Thrombosis, False aneurysm, Infection, Amputation, Deaths, etc.) comparable to predicate. | "It is important to note that no new type of complications were identified with Carboflo grafts." |
| Adverse events table shows 26 thrombosis for Carboflo vs 34 for Standard; 1 false aneurysm for both; 4 infection for Carboflo vs 5 for Standard; 28 amputation vs 26; 13 deaths vs 16. While some counts differ, the conclusion explicitly states, "no new type of complications were identified," implying overall comparability for safety in the context of substantial equivalence. The higher number of immediate re-operations for Carboflo (12 vs 6) is noted but not flagged as a significant safety concern in the conclusion for substantial equivalence. "Risk factors in patients with Carboflo and Standard ePTFE Vascular Grafts were similar (p > 0.05), except for Smoking." |
Study Details
The provided text describes both non-clinical (bench and animal) testing and a clinical study.
1. Sample Size and Data Provenance (for the Clinical Study):
- Test Set Sample Size:
- Carboflo group: 81 patients (received Carboflo grafts)
- Standard ePTFE group: 79 patients (received Standard ePTFE grafts)
- Total: 160 patients / 160 grafts
- Data Provenance: Prospective, multi-center clinical trial conducted in France between 1990-1994.
2. Number of Experts used to establish the ground truth for the test set and the qualifications of those experts:
The document does not specify the number or qualifications of experts used to establish the ground truth for the clinical study's outcomes (patency, adverse events). Clinical data was apparently collected and assessed by physicians involved in the trial, but no specific "expert panel" or "adjudication committee" is mentioned beyond the standard clinical practice implied by a prospective multicenter trial.
3. Adjudication method (for the test set):
The text does not explicitly state an adjudication method (like 2+1, 3+1). It mentions that "Adverse events were recorded and documented on Case Report Forms (CRF)," implying standard clinical trial data collection by investigators at each site, followed by central analysis.
4. If a multi-reader multi-case (MRMC) comparative effectiveness study was done:
No, this was not an MRMC study. It was a comparative clinical trial of two devices in human patients, not a study evaluating human readers' performance with and without AI assistance.
5. Effect size of how much human readers improve with AI vs without AI assistance:
Not applicable, as this was not an MRMC study involving AI assistance for human readers.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
Not applicable. This is a medical device (vascular graft) and the studies describe its physical performance and clinical outcomes, not an algorithm's performance.
7. The type of ground truth used:
For the clinical study, the ground truth was clinical outcomes data, specifically:
- Patency: Defined based on follow-up and interventions.
- Adverse Events: Documented clinical occurrences (e.g., thrombosis, infection, amputation, death).
- Patient demographics and risk factors: Recorded at baseline.
8. The sample size for the training set:
Not applicable. This is a medical device, not an AI model, so there is no "training set" in the context of machine learning. The studies described are for validation of the device's performance.
9. How the ground truth for the training set was established:
Not applicable, as there is no training set for an AI model. For the development of the graft itself, the "ground truth" would be established through engineering principles, material science testing, and pre-clinical animal models (as mentioned in the non-clinical testing section) to optimize the design before clinical trials.
§ 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.”