An aortic stent graft, sometimes called an endograft, is a covered medical device designed to be placed inside a weakened or bulging section of the aorta to redirect blood flow away from the diseased vessel wall. It combines a metal scaffold with a fabric-like covering, and it is the central device used in endovascular aneurysm repair, commonly known as EVAR. Rather than replacing the diseased segment of the aorta surgically, an aortic stent graft is delivered through the blood vessels themselves using catheter-based techniques, offering a less invasive route to treating an aneurysm than traditional open surgery.
How Is an Aortic Stent Graft Built?
An aortic stent graft typically consists of two structural components working together. The first is a metal scaffold, often made from nitinol, a flexible shape-memory alloy that allows the device to be compressed into a narrow delivery sheath and then expand back into its intended shape once released inside the vessel. The second component is a graft covering, commonly made from ePTFE or PTFE material, that lines the scaffold and creates a new, sealed channel for blood flow. Together, these components are engineered to conform to the native vessel while maintaining enough structural support to resist the pulsing pressure of arterial blood flow over time.
What Happens During the EVAR Procedure?
The EVAR procedure begins with small incisions or punctures in the groin to access the femoral arteries. Using X-ray (fluoroscopic) guidance and contrast dye, the physician threads a delivery catheter containing the compressed stent graft up through the vascular system to the site of the aneurysm. Once positioned precisely relative to the aneurysm's boundaries, the device is deployed, either by inflating a balloon in a balloon-expandable configuration or by retracting a sheath in a self-expanding configuration, allowing the stent graft to expand and anchor itself against the healthy vessel wall above and below the aneurysm. Depending on the aneurysm's shape and extent, additional graft segments may be added to fully line the diseased portion of the vessel.
How Does an Endograft Achieve Aneurysm Exclusion?
Aneurysm exclusion refers to the intended outcome of the procedure: creating a sealed, alternate pathway for blood flow so that the pressurized bloodstream no longer directly contacts the weakened aneurysm sac wall. Once the stent graft is properly seated and sealed against healthy vessel tissue at both ends, blood flows entirely through the new graft channel rather than through the surrounding aneurysm sac, which is intended to reduce further pressure on the weakened wall and lower the risk of continued expansion or rupture. Achieving a durable seal at the proximal and distal ends of the graft is one of the most technically important aspects of the procedure, since any persistent flow into the sac around the graft, known clinically as an endoleak, is a finding that surveillance imaging is specifically designed to detect.
What Design Features Support Long-Term Graft Stability?
Modern aortic stent grafts incorporate several design features intended to support stability once implanted. The Atlas Aortic Stent Graft, for example, is built on a nitinol scaffold with an ePTFE/PTFE graft covering and is available in balloon-expandable or self-expanding, sheath-based release configurations to suit different anatomic scenarios. The manufacturer describes a proximal mini-spring feature intended to support wall apposition at the upper sealing zone, along with what the manufacturer terms "lock stent technology," designed with two levels of fixation intended to help prevent modular disconnection between graft segments over time. Multiple tapered configurations are available to accommodate differing vessel diameters along the length of the treated segment. As with all such devices, indications, availability, and specific configuration options vary by country and should be confirmed through the official Instructions for Use (IFU).
Why Is Precise Sizing Important Before Implantation?
Before any aortic stent graft is selected, detailed pre-procedural imaging, typically CT angiography, is used to measure the diameter, length, and angulation of the aneurysm and the adjacent healthy vessel segments. Accurate sizing is central to achieving a proper seal, since a graft that is undersized or oversized relative to the native vessel may not appose the vessel wall adequately at the landing zones. This sizing process, along with assessment of the iliac and femoral access vessels, determines which stent graft configuration and delivery approach a physician selects for a given patient's anatomy. Additional endovascular device information is available in the aortic aneurysm and dissection repair product category.
How is it confirmed that the stent graft is working properly after EVAR?
Following EVAR, patients typically undergo scheduled surveillance imaging, most often CT scans, to confirm the graft remains properly sealed and that the aneurysm sac is excluded from blood flow without evidence of an endoleak. The frequency and type of imaging is determined by the treating physician.
Device availability and regulatory status vary by country. Please contact INVAMED or your authorized local distributor for current regulatory information applicable to your region.