IMPRA Carboflo™ ePTFE Vascular Grafts are intended for use in peripheral vascular applications to replace or bypass diseased or occluded blood vessels.

Device Description

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 graft. 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.

AI/ML Overview

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 core of the acceptance criteria is the demonstration of substantial equivalence to the predicate device, the IMPRA ePTFE Vascular Graft. This is primarily assessed through physical properties and clinical performance (patency rates and adverse events).

Acceptance Criteria Category	Specific Criteria	Reported Device Performance (IMPRA Carboflo™ ePTFE Vascular Graft)
Substantial Equivalence (Physical Properties)	Physical properties of Carboflo vascular grafts did not affect by addition of carbon particles to graft wall.	"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."
Patencty Rates	Similar patency rates to the predicate device (IMPRA ePTFE Vascular Graft).	24-month Cumulative Primary Patency: 36.8% (Carboflo) vs. 27.7% (Standard). 24-month Cumulative Secondary Patency: 42.7% (Carboflo) vs. 32.3% (Standard). (Note: "These results are not statistically significantly different at p=0.05.")
Device Safety (Adverse Events)	No new types of complications identified compared to the predicate device. Acceptable rates of known complications.	No new types of complications were identified. Thrombosis: 26 (Carboflo) vs. 34 (Standard) False Aneurysm: 1 (Carboflo) vs. 1 (Standard) Infection: 4 (Carboflo) vs. 5 (Standard) Other Adverse Events: 3 (Carboflo) vs. 2 (Standard) Amputation: 28 (Carboflo) vs. 26 (Standard) Deaths: 13 (Carboflo) vs. 16 (Standard)

Study Details

The provided document describes a clinical study and also refers to non-clinical (animal) studies and bench testing. Here's a breakdown of the relevant information:

1. Sample Size Used for the Test Set and Data Provenance:

Clinical Test Set:
- Total Patients: 160
- Carboflo Group: 81 patients
- Standard ePTFE Group: 79 patients
- Data Provenance: Prospective, multi-center, randomized clinical trial conducted in France between 1990-1994.
Non-Clinical (Animal) Test Set:
- Short-term pre-clinical studies: Dogs and rabbits (specific numbers not provided).
- Longer-term pre-clinical studies: Specific animal models not explicitly stated beyond "animal studies" (specific numbers not provided).

2. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:

This information is not explicitly provided for the clinical trial. Clinical trials usually involve investigators and potentially a Data Monitoring Committee, but their specific roles in establishing "ground truth" for each outcome are not detailed in this summary.
For the non-clinical studies ("Thrombus Free Surface Area" after 3 months, "reduced platelet accumulation"), the judgment would be made by veterinary pathologists or researchers. Specific numbers and qualifications are not mentioned.

3. Adjudication Method for the Test Set:

Not explicitly described. Clinical trials typically have methods for adjudication of adverse events and endpoints, but the specific process (e.g., 2+1, 3+1 consensus) is not detailed in this summary. Adverse events were "recorded and documented on Case Report Forms (CRF)".

4. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done:

No, this was not an MRMC study. This was a randomized controlled trial comparing two different medical devices in human patients, not a study evaluating human reader performance with or without AI assistance on various cases.

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

Not applicable. This device is a vascular graft, not an AI algorithm. Therefore, the concept of "standalone performance" for an algorithm doesn't apply here. The document describes the performance of the physical device itself.

6. The Type of Ground Truth Used:

Clinical Trial: The ground truth for patency was determined by the progression or failure of the graft over time, assessed through clinical follow-up and interventions. Adverse events were identified and recorded based on direct patient observation and medical documentation.
Non-Clinical (Animal) Studies:
- "Thrombus Free Surface Area" (measured after 3 months).
- "Platelet accumulation" (measured in dogs and rabbits).
Bench Testing: Physical properties of the grafts.

7. Sample Size for the Training Set:

Training Set for the Device: Not applicable in the context of an AI device. For a manufactured medical device like a vascular graft, "training set" would refer to manufacturing process development and quality control. The document mentions "Extensive bench testing and microscopic analysis" during manufacturing, but does not provide specific sample sizes that would be analogous to an AI training set.

8. How the Ground Truth for the Training Set was Established:

Not applicable as this is not an AI device. For device manufacturing, ground truth for quality control and material properties (e.g., tensile strength, porosity) would be established through standardized physical and chemical testing methods, often guided by industry standards (e.g., AAMI Vascular Graft Standard).

Summary

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K962639

Summary of Safety and Effectiveness for IMPRA Carboflo™ ePTFE Vascular Graft

SUBMITTER

Rajagopal R. Kowligi, Ph.D Senior Clinical Research Specialist IMPRA, Inc. 1625 West Third Street Tempe, AZ 85281

OCT -3 1996

DATE SUMMARY WAS PREPARED

June 18, 1996

NAME OF THE DEVICE

IMPRA Carboflo™ ePTFE Vascular Graft

IDENTIFICATION OF PREDICATE DEVICE

IMPRA ePTFE Vascular Graft

DESCRIPTION OF THE DEVICE

Extensive bench testing and microscopic analysis has shown that the carbon

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particles are an integral part of the wall and cannot be separated. The amount of carbon incorporated in each Carboflo vascular graft is less than 1% of the total weight of the graft.

INTENDED USE

IMPRA Carboflo™ ePTFE Vascular Grafts are intended for use in peripheral vascular applications to replace or bypass diseased or occluded blood vessels.

COMPARISON OF THE DEVICE CHARACTERISTICS TO THE PREDICATE

Physical properties of the Carboflo vascular grafts were compared to the values for Standard IMPRA ePTFE vascular grafts, using methods recommended by the AAMI Vascular Graft Standard or the FDA Guidance Document on Vascular Prostheses. 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.

NON-CLINICAL TESTING

Carbon containing surfaces in medical devices, e.g. Heart valves, have been shown to impart anti-thrombogenic properties1. Short-term pre-clinical studies have been conducted with IMPRA Carboflo™ ePTFE Vascular Grafts to determine the performance of carbon containing blood contact surface. 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 months2. Patencies of both Carboflo and Standard grafts were similar. 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 surface3.

l References on file
2 Data on file
3 References on file

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CLINICAL INFORMATION

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A multi-center, prospective, randomized clinical trial comparing IMPRA Carboflo™ ePTFE Vascular Grafts to commercially available ePTFE Vascular Grafts, was performed in France between 1990-1994. The purpose of the investigation was to compare the patencies of both IMPRA Carboflo ePTFE Vascular Grafts and Standard ePTFE Vascular Grafts. A total of 81 patients received Carboflo grafts and 79 received Standard ePTFE grafts. All grafts were implanted to treat lower extremity vascular disease. Of the 160 grafts, only 5 grafts (3 Carboflo, 2 Standard) were considered to be Above-Knee, and the remaining grafts were all Below-Knee.

73% of the distal anastomoses were direct graft to vessel, with the following types comprising the other anastomoses: venous patch (16%), distal arterio-venous fistula (5.8%), or interpositional vein cuff graft (5.2%). All implanted grafts were followed for at least 24 months, or until failure, lost to follow-up, or death of patient. Adverse events were recorded and documented on Case Report Forms (CRF).

Analysis

PRIMARY PATENCY was defined as the time between implant date and date of follow-up when the graft was patent, prior to the first intervention to correct complications. Interventions included immediate re-operations to correct any complication post implantation. SECONDARY PATENCY was defined as the time between implant date and date on which the graft is no longer patent or useful, after a series of interventions. Conventional life-tables were then constructed to determine the Cumulative Primary and Secondary Patencies. At the end of the 2 yr follow-up, patencies were as follows:

Cumulative Primary Patency for Carboflo grafts was 36.8 % compared to 27.7% for Standard grafts at the end of 24 months.

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.

DEVICE SAFETY was demonstrated by determining adverse events for both Carboflo and Standard grafts. Complications were counted as they were encountered and added up at the end of the study period for each patient. The results are tabulated below:

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Adverse event	Device Type
	Standard	Carboflo
No. At Start	79	81
No. LFU @2yrs *	7	17
No. Patent @2yrs	17	16
No. Immed. Redos	6	12
No. Failed @2yrs	52	43
Thrombosis	34	26
False aneurysm	1	1
Infection	5	4
Other adverse events	2	3
Amputation	26	28
Deaths	16	13

COMPLICATIONS: CARBOFLO VS. STANDARD

LFU = Lost to follow-up

It is important to note that no new type of complications were identified with Carboflo grafts.

RISK FACTORS in patients with Carboflo and Standard ePTFE Vascular Grafts were similar (p > 0.05), except for Smoking. There were a higher number of patients who were smokers, in the Carboflo group (p<0.05). The risk factors for the patients in this study were then compared to the risk factors for patients in USA who had treatment for peripheral vascular disease (information was summarized from published literature). Risk factors were comparable for both groups (p>0.05), except for Smoking. There were a higher number of patients who were smokers, in the US (p<0.05).

CONCLUSION

: : : :

IMPRA ePTFE Carboflo Vascular Grafts are substantially equivalent to the currently marketed IMPRA ePTFE Vascular Grafts.

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References -

Topic: Carbon containing surfaces- biocompatibility, performance

Gott, V. L .; et al .: "The anticlot properties of graphite coatings on artificial heart valves." 1. Carbon, 1:378, 1964.
1. Haubold, A. D .; et al .: "Carbon in medical devices." Biocompatibility of Clinical Implant Materials, Vol. II, edited by D. F. Williams, p. 3, 1983.
Olcott, E. L .: "Pyrolytic biocarbon materials." Journal of Biomedical Research 3. Symposium, No. 5 (Part 1), 209, 1974.
1. Adams, D .; et al .: "Carbon fiber-reinforced carbon as a potential implant material." Journal of Biomedical Material Research, 12:35, 1978.
Homsy. C. A .: "Biocompatibility of perfluorinated polymers and composites of these 5. polymers." Biocompatibility of Clinical Implant Materials, Vol II, edited by D. F. Williams, p. 59, 1981.
Lipsig, L. J .; et al .: "Clinical experience with transcutaneous vascular access." Dialysis ହିଁ । and Transplantation, 13(12):786, December 1984.
Gott, V. L .; et al .: "Heparin bonding on colloidal graphite surfaces." Science, 142:1297, 7. April 1963.
Whiffen, J. D .; et al .: "Heparin application to graphite coated intravascular prostheses." 8. Surgery, 56(2):404, August 1964.
ல். Gott, V. L .; et al .: "Techniques of applying a graphite-benzalkonium-heparin coating to various plastics and metals." Transactions American Society of Artificial Internal Organs, 10:213, 1964.
Haubold, A. D.; et al.: "Ultra-low temperature isotropically (ULTI) deposited carbon 10. (Biolyte); a promising new flexible blood interface material." Cardiovascular Diseases, 4(4):369, 1977.
1. Sharp, W. V .; et al .: "Pyrolytic carbon-coated grafts." Graft Materials in Vascular Surgery, edited by H. Pardik, p. 203, 1978.
1. Sharp, W. V .: "Present Status of carbon grafts." Yascular Grafting: Clinical Applications of Techniques, edited by J. Wright, p. 326, 1983.

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Debski, R .; et al .: "Polytetrafluoroethylene grafts coated with ULTI carbon." 13. Transactions American Society of Artificial Internal Organs, 28:456, 1982.
Sharp, W. V.; et al.: "A bioelectric polyurethane elastomer for intravascular replacement." 14. Transactions American Society of Artificial Internal Organs, 12:179, 1966.
Sharp. W. V .: "Bioelectric properties of the vascular system as related to artificial internal ા રે . organs." Surgery, 61(5):763, May 1967.
Sharp, W. V .; et al .: "Electrolour: a new vascular interface." Transactions American 16. Society of Artificial Internal Organs, 14:73, 1968.
Taylor, B. C.; et al .: "The importance of the zeta potential, ultrastructure, and electrical 17. conductivity of the in-vivo performance of polyurethane-carbon black vascular prostheses." Transactions American Society of Artificial Internal Organs, 17:22, 1971.
Miller, B. G.; et al.: "Electrical conductivity: effect on intravascular performance of 18. foams, velour, flock, and fabric." Transactions American Society of Artificial Internal Organs, 20:91, 1974.
Bokros, J. C.; et al.: "Control of structure of carbon for use in bioengineering." 19. Chemistry and Physics of Carbon, Vol. 9, edited by F. L. Walker, Jr., Marcei Dekker, New York, 1973.
Baier, R. E .; et al .: "Surface chemical evaluation of thromboresistant materials before and 20. after venous implantation." Transactions American society of Artificial Internal Organs, 16:50, 1970.
Sawyer, P. N .; et al .: "Bio-electric phenomena as an etiologic factor in intravascular 21. thrombosis." American Journal of Physiology, 175:103, October 1953.
Sawyer, P. N.; et al.: "Relations of abnormal and injury electrical potential differences in 22. intravascular thrombosis." American Journal of Physiology, 175:108, October 1953.
Sawyer, P. N.; et al .: "Electric potential differences across the normal aorta and aortic 23. grafts of dogs." American Journal of Physiology, 175:113, October 1953.
Goldfarb, D .; et al .: "Graphite-expanded polytetrafluoroethylene: an improved small 24. artery prosthesis." Transactions American Society of Artificial Internal Organs, 23:268, 1977.
Schmidt, S. P., Ph. D.; et al.: "In vivo performance of carbon-coated PTFE vascular 25. grafts in a canine model." Presented at the 15th Annual Meeting of the Society for Biomaterials, Lake Buena Vista, Florida, USA, April 28 - May 2, 1989.

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1. Tsuchida, Hiromitsu, M.D., Ph. D .; et al .: "Modified polytetrafluoroethylene: Indium 111-labeled platelet deposition on carbon-lined and high-porosity polytetrafluoroethylene . . grafts." Journal of Vascular Surgery, 16(4):643-650, October 1992.
1. Babatasi, G .; et al .: "Indium-labelled platelet deposition in carbon-lined modified polytetrafluoroethylene grafts in an experimental model: aortic replacement in rabbits. Effects of heparin and hirudin." Cardiovascular Surgery, September 1994.
1. Bacourt, F .; A.U.R.C. (Group of University hospitals): "Etude Prospective Randomisee Comparative de Protheses PTFE carbone et PTFE standard in Position Sous-articulaire." Presented at the meeting of French Speaking Vascular Society (IX Congress: SCV en langue francaise. June 16, 1994).
1. Baste, J. C .; et al .: "Etude Prospective Comparative D'Une Protheses PTFE Carbone Versus Prothese Standard Dans Les Abords Vasculaires Pour Hemodialyse Chronique-Resultats A Un An." Presented at the meeting of French Speaking Vascular Society (VIII Congress: SCV en langue francaise, June 24 - 26, 1993).
Bourquelot, P. D .; et al .: "Pontages PTFE-Carbone et PTFE-Standard en Hemodialyse 30. etude Preliminaire a 36 mois - N = 97." Presented at the meeting of French Speaking Vascular Society (VIII Congress: SCV en langue francaise, June 24 - 26, 1993).
1. Ruehland, D., M.D .: "Use of IMPRA Carbon-Lined PTFE Prostheses: A Preliminary Report." Unpublished, IMPRA ePTFE Carbon-Lined Vascular Graft Design File,
1. Moggi, L. MD, " Reconstructive Surgery: Developments in Grafts", Critical Ischaemia, Vol. 4, no.3, 71-76.

Regulation Number and Section

§ 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.”