A stent graft is a tube-shaped medical device made from a metal skeleton wrapped in a synthetic fabric membrane, designed to reinforce or reline a damaged blood vessel from the inside. Doctors thread it through a small incision, usually in the groin, and guide it to the problem site using real-time imaging. Once in position, the device expands to form a new channel for blood flow, sealing off weak spots like aneurysms or tears in the vessel wall. Though the concept sounds straightforward, stent grafts come in a surprising range of designs, are used across many different clinical scenarios, and carry a unique set of trade-offs that anyone facing this procedure should understand.
How a Stent Graft Is Built
Every stent graft shares the same basic architecture: a metallic scaffold covered by a polymer membrane. The metal framework, often made from nitinol (a nickel-titanium alloy that can remember its shape) or stainless steel, provides the structural backbone that holds the vessel open. The fabric covering, typically expanded polytetrafluoroethylene (ePTFE, the same material used in Gore-Tex) or polyester (polyethylene terephthalate, or PET), acts as a barrier that separates blood flow from the diseased vessel wall.1Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications. Mechanical properties of stent–graft materials This fabric barrier is what distinguishes a stent graft from a plain bare-metal stent, which is just a wire mesh without a covering. In a bare stent, tissue and clot can grow through the mesh gaps. The graft fabric physically blocks that ingrowth, which is why stent grafts tend to stay open longer in hostile environments like tumor-invaded veins.2Journal of Vascular and Interventional Radiology. Technical Failure, Effectiveness, and Safety of Bare-Metal Stents versus Stent Grafts in Malignant Portal Vein Occlusion
Research into how these materials perform under stress has found that the specific type of nitinol used in the stent significantly affects flexibility, how tightly the device can be compressed for delivery, and how well it resists fatigue over years of pulsing blood flow. The graft fabric matters too: PET grafts appear to enhance flexibility and fatigue life compared with ePTFE, though the differences in stress distribution between the two fabrics are small.3PubMed Central. Optimizing Aortic Arch Stent-Graft Performance Through Material Science: An Exploratory Study For the patient, the practical upshot is that modern stent grafts are engineered to flex with the body’s movements and withstand millions of heartbeat-driven pressure cycles without breaking apart, though as we will see, structural failures do still occur.
How the Procedure Works
Most stent graft placements happen through the femoral artery in the groin, a technique called percutaneous transfemoral access. A large-bore sheath is inserted into the artery, and the compressed stent graft is threaded up through the blood vessels to the target site under X-ray guidance.4PubMed Central. Large-Bore Transfemoral Arterial Access: Techniques and Troubleshooting Once in position, the device is released from its delivery system. Self-expanding nitinol stent grafts spring open on their own; balloon-expandable versions are inflated with a small balloon to press them against the vessel wall. The surgeon confirms placement with a dye injection (angiography), checking that blood flows through the new channel and that no leaks have formed around the device.
Because the device enters through a puncture or small cut rather than through a large incision in the chest or abdomen, the procedure is far less invasive than traditional open surgery. Hospital stays are shorter, recovery is faster, and the approach avoids the need for general anesthesia in some cases, though many patients still receive it. The groin access site is usually closed with suture-based closure devices placed before the sheath is introduced.5Journal of Clinical Imaging Science. Stent graft for a longstanding femoral artery pseudoaneurysm with arteriovenous fistula
Treating Abdominal Aortic Aneurysms
The single most common use of stent grafts is repairing abdominal aortic aneurysms (AAAs), dangerous balloon-like bulges in the body’s largest artery. Endovascular aneurysm repair, or EVAR, involves placing a bifurcated (Y-shaped) or tubular stent graft over the aneurysm to exclude it from the blood circulation. Once sealed off, blood pressure no longer pushes against the weakened wall, and the risk of rupture drops dramatically.6PubMed Central. Endovascular Aneurysm Repair for Abdominal Aortic Aneurysm: A Comprehensive Review
A typical EVAR procedure involves deploying the main body of the stent graft just below the renal arteries, then extending limbs down into both iliac arteries to anchor the device. Balloon molding at each seal zone ensures a tight fit. Patients often go home within a few days.7PubMed Central. Clinical benefits and risks of the wall-push technique in endovascular repair of abdominal aortic aneurysm with severely angulated neck The procedure has been performed since 1990, when Argentine surgeon Juan Parodi treated the first patient by combining a polyester tube graft with a balloon-expandable stent. Earlier, in 1987, Ukrainian surgeon Nikolai Volodos had placed the world’s first endovascular stent graft in a thoracic aortic aneurysm. From those pioneering cases, the technology evolved from simple straight tubes to the modular bifurcated designs used today.8European Journal of Vascular and Endovascular Surgery. A 35 Year History of Stent Grafting, and How EVAR Conquered the World
Stent Grafts in the Thoracic Aorta
Stent grafts also play a major role in treating problems in the upper portion of the aorta that runs through the chest. Thoracic endovascular aortic repair, or TEVAR, is now the go-to treatment for type B aortic dissection, a condition where the inner layer of the aortic wall tears and blood forces its way between the layers. This type of dissection accounts for roughly 30 to 60 percent of all aortic dissections.9PubMed Central. Central nervous injury risk factors after endovascular repair of a thoracic aortic aneurysm with type B aortic dissection The stent graft covers the tear, redirecting blood into the true channel and allowing the false channel to clot and heal. Not every dissection needs immediate intervention; among patients initially managed with medication alone, under 9 percent went on to need TEVAR within the following ten months.10PubMed Central. National Trends in the Use and Timing of Thoracic Endovascular Aneurysm Repair After Type B Aortic Dissection
TEVAR has also become a preferred option for traumatic aortic injuries from high-speed accidents or falls. Because the procedure avoids cracking open the chest and does not require blood thinners the way open surgery does, it can be performed in critically injured patients without destabilizing other injuries to the lungs, brain, or abdomen.11PubMed Central. Acute Traumatic Thoracic Aortic Injury: Considerations and Reflections on the Endovascular Aneurysm Repair In emergency ruptures of the descending thoracic aorta, endovascular repair has shown favorable short-term results, though long-term surveillance remains essential, and researchers are still working out whether stent grafts serve as a permanent fix or sometimes as a bridge to later open surgery.12Annals of Vascular Surgery. Emergency Treatment of Acute Rupture of the Descending Thoracic Aorta Using Endovascular Stent-Grafts
Lesions near the left subclavian artery present a particular challenge because the stent graft may not have enough healthy aorta above the injury to anchor against. Branched stent grafts, which have side extensions that preserve blood flow to branch arteries, have been developed for these situations. One case report documented complete exclusion of a traumatic pseudoaneurysm using a single-branched stent graft, with no endoleak or stent migration at three-year follow-up.13PubMed Central. Emergency endovascular repair of blunt thoracic aortic injury-related pseudoaneurysm using a castor single-branched stent graft
Stent Grafts Versus Open Surgery
The question most patients and their families have is straightforward: is a stent graft better than traditional open surgery? The answer depends on what time horizon you care about. In the short term, stent grafts clearly win. A large meta-analysis found that perioperative mortality with EVAR was roughly half that of open surgical repair. One study of over a thousand patients put 30-day mortality at about 1.4 percent for EVAR versus 3.8 percent for open repair, with complication rates of 18 percent versus 32 percent.14European Journal of Cardiovascular Medicine. Endovascular vs. open surgical repair of abdominal aortic aneurysm: long-term outcomes
The picture shifts at longer follow-up. After about three years, the survival advantage fades. One large analysis found no significant difference in long-term mortality between the two approaches after adjustment.15JAMA Surgery. Survival After Endovascular vs Open Aortic Aneurysm Repairs And EVAR patients face higher rates of late reintervention, meaning they are more likely to need additional procedures down the road. A pooled analysis estimated reintervention rates roughly twice as high with EVAR over long-term follow-up.16Annals of Vascular Surgery. Aortic Aneurysm Endovascular versus Open Repair for Non-Complex Abdominal Aortic Aneurysms: A Systematic Review and Meta-Analysis Late aneurysm ruptures also occur more often after EVAR than after open repair. In other words, the stent graft gets you through the procedure more safely, but open repair may be more durable once you survive it.
This trade-off shapes clinical decisions. Younger, healthier patients who can tolerate open surgery may benefit from the long-term durability of traditional repair. Older or sicker patients who face higher surgical risk often benefit more from the gentler stent graft approach, even if it means more follow-up visits and potential touch-up procedures later.
Endoleaks and Other Complications
The complication most unique to stent grafts is an endoleak, which is blood leaking into the aneurysm sac around or through the device. Endoleaks can occur in up to a quarter of EVAR patients.17PubMed Central. Management of Endoleaks following Endovascular Aneurysm Repair They come in several types. Type I endoleaks occur at the top or bottom seal zones, where the graft meets the artery wall, and generally require prompt treatment. Type II endoleaks, the most common variety, happen when small branch arteries feed blood backward into the sac. Many type II endoleaks are harmless and resolve on their own; the case report mentioned earlier describes one being managed conservatively with surveillance imaging.
Beyond leaks, the device itself can deteriorate. Stent grafts live in a relentlessly pulsatile environment, absorbing the force of every heartbeat. Over time, this causes metal fatigue. In one study examining a specific stent graft design, suture breaks were found in nearly 90 percent of patients, and metal-ring fractures were seen in about 18 percent. Patients with major suture breaks had roughly four and a half times the risk of device migration.18PubMed. Detection of broken sutures and metal-ring fractures in AneuRx stent-grafts by using three-dimensional CT angiography after endovascular abdominal aortic aneurysm repair Structural failure can also involve graft fabric distress or complete stent detachment from the fabric, sometimes leading to device migration and requiring emergency reoperation.19PubMed Central. Stent Graft Migration Due to Structural Failure Nine Months After Thoracic Endovascular Aortic Repair Using Valiant Navion
Another long-term concern is poor biological integration. An analysis of explanted stent grafts found that some devices showed significant material degradation and, critically, a lack of neointima formation. Neointima is the thin tissue layer that ideally grows over the device and helps anchor it to the vessel wall. Without it, the graft lacks biological fixation, increasing the risk of both endoleak and migration.20PubMed. Implant degradation and poor healing after endovascular repair of abdominal aortic aneurysms: an analysis of explanted stent-grafts This is one reason lifelong surveillance is mandatory after any stent graft procedure.
Infection After Stent Graft Placement
Stent graft infection is rare but extremely serious. A systematic review of over 400 patients with infected aortic endografts found that Staphylococcus species were the most commonly identified bacteria (about 30 percent of cases), followed by Streptococcus (about 15 percent) and fungal infections (about 9 percent). Roughly a quarter of patients had cultures that grew multiple organisms. The vast majority (90 percent) underwent surgical treatment, which could mean removing the infected graft and reconstructing the artery. Patients who had surgery survived at a higher rate than those treated conservatively with antibiotics alone (58 percent versus 33 percent). Prognosis was notably worse when the infection involved a thoracic stent graft or had created a connection between the aorta and the esophagus or bronchial tree.21Annals of Vascular Surgery. Management and Outcomes of Aortic Endograft Infection: A Systematic Review and Meta-Analysis
Lifelong Surveillance
Unlike open surgical repair, where a successful operation is largely the end of the story, a stent graft demands ongoing monitoring for the rest of the patient’s life. Current best-practice guidelines call for a CT angiography scan within 30 days of the procedure to check for problems and serve as a baseline. If that initial scan is clean, many patients can be monitored with annual ultrasound, which avoids repeated radiation exposure. Patients with endoleaks or other concerns on the initial scan typically continue with CT-based follow-up.22PubMed. Best Practice Guidelines: Imaging Surveillance After Endovascular Aneurysm Repair CT angiography remains the reference standard for evaluating graft integrity, aneurysm sac size, and surrounding anatomy, though newer approaches combining contrast-enhanced ultrasound with CT fusion are being explored to reduce the cumulative radiation and contrast dye burden of repeated scanning.23Radiation. Contrast-Enhanced Ultrasound and CT Fusion Imaging in EVAR Follow-Up: Diagnostic Workflow, Endoleak Detection, and Imaging Pitfalls
This surveillance commitment is one of the hidden costs of choosing a stent graft over open repair, and it factors into the cost-effectiveness discussion. An analysis from the Netherlands found that EVAR was slightly cheaper overall and slightly more effective than open repair, but that advantage was highly sensitive to the price of the device and the extent of follow-up imaging needed.24PubMed. Cost-effectiveness of Elective Endovascular Aneurysm Repair Versus Open Surgical Repair of Abdominal Aortic Aneurysms A U.S. Veterans Affairs trial found that total healthcare costs over the long run did not differ significantly between EVAR and open repair; the savings from shorter initial hospital stays with EVAR were offset by the costs of secondary procedures and imaging.25PubMed. Long-term Cost-effectiveness in the Veterans Affairs Open vs Endovascular Repair Study of Aortic Abdominal Aneurysm
Uses Beyond the Aorta
While the aorta gets most of the attention, stent grafts are also used in peripheral arteries, particularly in the iliac and femoral arteries that supply the legs. For patients with severe blockages in the aorto-iliac segment who face limb-threatening ischemia, covered stents (another name for stent grafts in this context) have shown strong patency rates, with one study reporting about 96 percent of devices still open at one year and about 90 percent at three years.26Journal of Vascular Societies Great Britain and Ireland. Outcome of covered stents for severe aorto-iliac occlusive disease (AIOD) in patients with chronic limb-threatening ischaemia Earlier work evaluating stent grafts in the iliac and leg arteries found the technique to be feasible with good technical results, though complications were more common in the smaller femoropopliteal arteries than at the iliac level.27PubMed. Occlusive and aneurysmal peripheral arterial disease: assessment of a stent-graft system
Stent grafts have also been explored outside the vascular system entirely. Covered nitinol stents have been placed temporarily in the airways to treat benign tracheobronchial strictures, keeping narrowed breathing passages open while the underlying tissue heals.28PubMed. Benign tracheobronchial strictures: long-term results and factors affecting airway patency after temporary stent placement And as noted earlier, stent grafts are used in the portal vein of cancer patients whose tumors have compressed or invaded this critical vessel, where the fabric barrier outperforms bare stents in keeping the channel open.
Advanced Designs for Complex Anatomy
Standard stent grafts work well when there is a sufficient length of healthy artery above and below the aneurysm to create a reliable seal. When the aneurysm extends close to branch arteries like the renals or the vessels feeding the intestines, surgeons need more sophisticated hardware. Fenestrated stent grafts have holes or windows cut into the fabric that align with branch arteries, allowing blood to continue flowing to vital organs while the aneurysm is still sealed off. Studies have confirmed that fenestrated physician-modified endografts are safe and effective for treating aneurysms that sit right at the level of the renal arteries.29PubMed Central. Fenestrated Physician-Modified Endografts for Preservation of Main and Accessory Renal Arteries in Juxtarenal Aortic Aneurysms
Planning these procedures demands extreme precision. Some centers now use patient-specific 3D-printed models of the aorta to rehearse graft placement before the actual surgery. In a comparison of 3D-print-guided versus conventional planning, both groups showed similarly low rates of severe complications within 30 days, with no postoperative aneurysm rupture or stent migration in either group.30PubMed Central. Patient-specific static and dynamic 3D-printed models for planning endovascular repair of complex aortic disease with physician-modified stent grafts The 3D models help surgeons cut fenestrations in exactly the right spots and anticipate how the graft will behave once deployed.
Smaller Devices and Where the Technology Is Heading
One of the most active areas of improvement is making stent grafts smaller. The delivery sheath that carries the compressed device through the artery needs to be wide enough to hold the graft, and larger sheaths mean more risk of injuring the access artery. Low-profile stent grafts, which can be squeezed into sheaths three to four French sizes narrower than standard devices, make the procedure accessible to patients with smaller or more diseased arteries. Early data on these slimmer thoracic stent grafts have shown favorable safety and effectiveness, including good deployment accuracy and wall contact, both of which are thought to predict long-term durability.31PubMed Central. Early results of a low-profile stent-graft for thoracic endovascular aortic repair
Low-profile fenestrated and branched grafts are also arriving. A comparison of low-profile versus standard-profile fenestrated-branched devices for complex aortic aneurysms found similar technical success rates (around 96 to 97 percent), but the low-profile group had shorter operating times, lower radiation exposure, and less contrast dye use.32PubMed. Outcomes of low- and standard-profile fenestrated and branched stent grafts for treatment of complex abdominal and thoracoabdominal aortic aneurysms Less contrast is particularly welcome for patients with compromised kidney function, a common concern in the elderly population that makes up the majority of aneurysm patients.
Beyond miniaturization, researchers are looking at better graft fabrics, improved fatigue-resistant alloys, and drug-eluting coatings that might reduce the inflammation and tissue overgrowth that can cause problems at seal zones. Off-the-shelf branched grafts that can accommodate different anatomies without custom manufacturing are another frontier, with devices now available in multiple diameter combinations to fit a wider range of patients.33PubMed Central. E-nside Off-the-Shelf Inner Branch Stent Graft: Technical Aspects of Planning and Implantation Custom-made grafts can take weeks to manufacture, a delay that is not an option in urgent situations. Expanding the off-the-shelf inventory could make complex endovascular repair available to more patients, faster.