An endograft is a medical device used to repair damaged or weakened major blood vessels, most commonly the aorta. This device is permanently implanted inside the artery to provide a new, reinforced pathway for blood flow. It allows for a minimally invasive approach to vascular repair, offering an alternative to traditional open surgery and stabilizing the compromised vessel to prevent rupture.
Anatomy of the Endograft
The endograft is a modular system composed of a metal frame and a fabric covering. The metal component is a self-expanding stent structure, often made from a superelastic alloy like Nitinol. This stent anchors the device securely against the artery wall and maintains its open, tubular shape once deployed.
The fabric covering is a specialized, durable material like woven polyester or expanded polytetrafluoroethylene (PTFE). This fabric is sewn onto the stent frame to create a blood-impermeable lining that acts as the new inner wall of the artery. The device is flexible and collapsible, allowing it to be compressed into a narrow catheter for delivery through smaller arteries.
The Conditions Endografts Treat
Endografts treat aneurysms, which are bulges or areas of weakness in an artery wall. These weak spots balloon outward due to blood flow pressure and can rupture if left untreated, causing severe internal bleeding. The endograft relines the artery, diverting blood flow away from the weakened area.
The most common application is for abdominal aortic aneurysms (AAA) in the lower aorta. They also treat thoracic aortic aneurysms (TAA) located in the upper aorta within the chest cavity. In both cases, the device excludes the aneurysm sac from the circulatory system, eliminating pressure on the vessel wall.
The Endovascular Implantation Procedure
Endograft implantation is performed through Endovascular Aneurysm Repair (EVAR) for the abdomen or Thoracic Endovascular Aortic Repair (TEVAR) for the chest. This minimally invasive technique uses small incisions, typically in the groin, to access the femoral arteries. A catheter is then inserted into the artery and guided toward the aneurysm site.
The surgeon uses real-time X-ray imaging (fluoroscopy) to navigate the catheter and the collapsed endograft. Once the delivery system reaches the aneurysm site, the endograft is positioned to span the weakened segment. The device is deployed, causing the metal stent frame to expand and firmly seal the fabric lining against the artery walls above and below the aneurysm.
This deployment creates a durable conduit, rerouting blood flow through the center of the endograft. This action immediately relieves pressure on the aneurysm sac, which is sealed off from circulation. After confirming the seal, the catheter is removed, and the incisions are closed.
Recovery and Long-Term Monitoring
The endovascular approach offers faster recovery compared to traditional open surgical repair, which requires a large incision. Most patients leave the hospital within one to two days following the procedure, and a return to light activity is often possible within one to two weeks.
Long-term surveillance is necessary to ensure the continued integrity and positioning of the device. Patients are scheduled for regular follow-up imaging, typically CT scans or ultrasounds, starting one month after the procedure and continuing annually for life. This imaging checks that the endograft remains stable and that the aneurysm sac is not re-pressurized.
The primary complication that monitoring seeks to detect is an endoleak, which is the persistent flow of blood back into the aneurysm sac, outside the new endograft lining. Endoleaks can occur if the graft does not seal completely against the artery wall or if blood enters the sac through small branch vessels. Detecting an endoleak is important because the continued pressure could lead to the aneurysm expanding or rupturing, necessitating further intervention.