ASTM F3849-26

1.1 This guide covers how to conduct an in vitro evaluation of leakage for stent graft proximal and distal seal zones. Leakage flow rate at the relevant location(s) is measured from the stent graft in a mock vessel while applying physiologic pressures and flow rates to simulate in vivo conditions.

1.2 This standard is applicable to stent grafts deployed into a native vessel and does not address the sealing of stent grafts deployed in other vascular prostheses. The evaluation of seal zone leakage is not necessary for endovascular prostheses intended for clinical uses for which seal zone leakage is unlikely to occur or would not likely be associated with adverse clinical sequelae (e.g., treatment of occlusive lesions).

1.3 This guide applies to balloon-expandable and self-expanding stent grafts used in the treatment of vascular disease. This standard does not specifically address any attributes unique to coated stents, polymeric stents, or biodegradable stents, although the application of this guide to those products is not precluded.

1.4 This standard does not specifically address testing with a blood mimic, but the standard may still be relevant in designing a test using a blood mimic.

1.5 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

5.1 Guidance is provided for in vitro measurement of the leakage at seal zones of stent grafts when used to treat vascular disease at relevant boundary conditions to assess conformance to product specifications and guidance documents. It may be used to support regulatory submissions, quality control, and manufacturing (e.g., process changes). Note: ISO 25539-1 (2017) allows for determination of seal zone leakage, alternatively, through evaluation of Type I endoleaks in a clinical study.

5.2 This guide depends on the use of controlled physiologic conditions and the ability to minimize unintended leakage.

5.3 The recommended test fluid in this guide is water. Therefore, when water is used, a known limitation is that the measured leakage rate may not be representative of the expected in vivo leakage rate. The guide enables the comparison of different stent grafts. These stent grafts may be devices with a known clinical history.

5.4 This guide is not intended to simulate the effect of tissue ingrowth over time, endothelization, or thrombosis on leakage at the seal zone.