Understanding Endoleaks: Causes, Symptoms, Treatment and Prevention

An endoleak is a possible complication of endovascular aneurysm repair (EVAR), a procedure in which a stent graft is placed in the aorta to strengthen a weakened section affected by an aneurysm. Ideally, the stent graft will create a new pathway for blood flow, effectively isolating the aneurysm. However, an endoleak may occur if blood continues to flow into the aneurysm sac outside the stent graft. This persistent blood flow can lead to aneurysm enlargement or rupture, posing significant health risks.

While endoleaks do not directly impact heart function, they can affect overall cardiovascular health. A ruptured aneurysm can cause severe internal bleeding, leading to a sudden drop in blood pressure and increasing the strain on the heart. Therefore, understanding and monitoring endoleaks is vital for maintaining optimal heart health. An effective prevention strategy typically includes regular follow-up imaging after aneurysm repair, which can help a physician identify endoleaks before they become problematic. Timely detection and intervention can help prevent aneurysm rupture and other complications, ensuring the best possible health outcome.

What Are the Types of Endoleaks?

There are five recognized types of endoleaks, each with distinct causes and implications:

• Type 1 – An inadequate seal at the attachment site of the stent graft can allow blood to flow directly into the aneurysm sac. Based on its location, a type 1 endoleak may be further classified as:
  • Type 1a – The leak occurs at the upper (proximal) end of the graft.
  • Type 1b – The leak occurs at the lower (distal) end of the graft.
  • Type 1c – The leak occurs at the iliac occluder,
  All type 1 endoleaks are considered high-risk due to the potential for increased pressure within the aneurysm sac, which can lead to rupture.
• Type 2 (most common) – Retrograde blood flow into the aneurysm sac can occur via branch vessels, such as lumbar arteries or the inferior mesenteric artery. Unlike type 1, type 2 endoleaks often have low pressure and resolve spontaneously, although a persistent leak may require treatment.
• Type 3 – A defect or separation in the stent graft material, such as a fabric tear or a disconnection between its modular components, can allow blood to flow into the aneurysm sac. Type 3 endoleaks are generally serious and necessitate prompt repair.
• Type 4 – Due to the porosity of the graft fabric, blood can seep through the graft and into the aneurysm sac. Usually, type 4 endoleaks are transient and resolve without intervention.
• Type 5 (endotension) – Endotension is characterized by continued expansion of the aneurysm sac without any detectable endoleak in imaging studies. The exact cause is not well understood, and management strategies can vary.

What Causes Endoleaks and What Are the Risk Factors?

Endoleaks can have several causes, including:

• Poor graft seal – A poor seal at the proximal or distal end of the stent graft or the iliac occluder can allow blood to flow into the aneurysm sac.
• Damaged stent graft – A tear, defect or misalignment of the stent graft components can allow blood to leak through the wall of the graft.
• Permeable graft material – If the stent graft fabric is porous, blood may seep through it.
• Pre-existing vessels – Blood vessels that originate in the aneurysm sac can allow blood to flow back into the sac.

Several factors can increase the risk of developing endoleaks. These include:

• Anatomical factors – A large aneurysm, calcified or thrombus-laden vessels or a complex aortic anatomy, such as a short or highly angulated neck, can interfere with the proper sealing and fixation of a stent graft, potentially leading to endoleaks.
• Patient characteristics – Advanced age is associated with a higher incidence of certain types of endoleaks, particularly type 2. Additionally, health conditions such as hypertension and obesity may contribute to an increased risk of endoleaks.
• Surgical factors – Procedural aspects, such as hypogastric artery coil embolization and distal graft extension, have been linked to persistent type 2 endoleaks. The type of graft used during EVAR can also influence the likelihood of endoleak development.

What Are the Warning Signs and Symptoms of Endoleaks?

Endoleaks usually do not cause noticeable symptoms. Most are detected during routine follow-up visits and imaging studies performed after endovascular aneurysm repair.

That said, an endoleak that leads to the expansion or rupture of the aneurysm sac can become a life-threatening emergency. The warning signs include:

• Pain – Sudden or severe pain in the abdomen, back or side
• Throbbing abdominal lump – A noticeable, pulsating mass in the midsection
• Hypotension – A significant drop in blood pressure due to internal bleeding
• Tachycardia – Rapid heartbeat as the body attempts to compensate for blood loss

How Are Endoleaks Diagnosed?

Endoleaks are typically diagnosed through imaging studies conducted after endovascular aneurysm repair. The primary imaging tests used for detection include:

• Computed tomography angiography (CTA) – The most commonly employed technique for endoleak detection, CTA offers high-resolution images that can help a physician identify the presence and type of any endoleaks.
• Magnetic resonance angiography (MRA) – For patients with contraindications to the iodinated contrast agents used in CTA, MRA may be an alternative imaging modality.
• Ultrasonography (US) – Doppler ultrasound, including superb microvascular imaging (SMI) and other advanced techniques, can help a physician detect and classify any endoleaks, especially in follow-up evaluations.

Each imaging modality has its own advantages and limitations, and the choice can vary depending on patient-specific factors.

How Are Endoleaks Treated?

Endoleak treatment can vary based on the type and severity of the leak and the patient’s overall health. Type 1 endoleaks are usually treated with endovascular interventions to seal the leak, such as securing the stent graft with endostaples or placing additional grafts.

Type 2 endoleaks may be managed with:

• Endovascular embolization – This minimally invasive procedure involves guiding a catheter to the site of the endoleak and delivering embolic agents, such as coils or glue, to block the flow of blood into the aneurysm sac.
• Direct sac puncture – Under imaging guidance, a needle is inserted directly into the aneurysm sac to deliver embolic agents, effectively sealing the endoleak.

If endovascular treatment for a type 2 endoleak is unsuccessful or not feasible, surgical intervention may be considered, such as laparoscopic, robotic-assisted or open surgical ligation of the feeding vessels.

Type 3 endoleaks are typically addressed by deploying additional stent grafts to cover the defect and restore the integrity of the repair. Type 4 endoleaks often resolve spontaneously and do not require intervention. Type 5 endoleaks treatment may include endovascular or surgical interventions based on the clinical scenario.

What Are the Complications and Long-Term Effects of Endoleaks?

Endoleaks can lead to several complications and long-term effects. These include:

• Aneurysm sac expansion – A persistent endoleak may cause the aneurysm sac to enlarge over time, increasing the risk of rupture.
• Aneurysm rupture – If an endoleak leads to significant sac expansion, the aneurysm may rupture, resulting in life-threatening internal bleeding.
• Need for reintervention – An endoleak may require additional treatment to seal the leak and prevent further complications.
• Device-related complications – Issues with the stent graft, such as kinking, breakage and fabric tears, may compromise the effectiveness of the repair.

How Can Endoleaks Be Prevented?

Several strategies can be implemented to help prevent the development of endoleaks after endovascular aneurysm repair. These include:

• Meticulous preoperative planning – Detailed imaging assessments, such as CTA or MRA, are essential to help the surgeon evaluate the anatomy of the aneurysm, select an appropriately sized stent graft and determine the optimal landing zones.
• Device selection – Choosing a stent graft precisely tailored to the patient's anatomy can enhance the seal and fixation, thereby reducing the risk of endoleaks. Advancements in stent graft technology continue to improve EVAR outcomes.
• Precise intraoperative techniques – Angiography can be used intraoperatively to confirm that the stent grant is properly positioned and securely attached, and also to detect any immediate leaks.
• Additional interventions – For patients at high risk of type 2 endoleaks, prophylactic embolization of certain vessels, such as the inferior mesenteric artery or lumbar arteries, may be considered.
• Postoperative surveillance – Regular follow-up imaging studies, such as CTA or US, are vital to monitor for signs of endoleaks. Early detection through vigilant surveillance can allow for timely intervention and prevent potential complications.

Living With an Endoleak

Living with an endoleak after endovascular aneurysm repair typically involves regular medical check-ups and follow-up imaging studies to monitor the condition. Monitoring is essential because endoleaks typically do not cause noticeable symptoms.

In some cases, an endoleak may resolve on its own. However, if an endoleak leads to aneurysm sac expansion, it can increase the risk of rupture, which is a life-threatening emergency. Therefore, the patient should maintain a close relationship with their health care provider and adhere to the recommended surveillance protocols to manage the condition effectively and ensure prompt treatment if necessary.

Frequently Asked Questions (FAQs) About Endoleaks

The following FAQs and corresponding answers provide additional information about endoleaks:

Do all endoleaks require immediate treatment?

Not all endoleaks necessitate immediate intervention. The need for treatment can vary depending on the type of endoleak and its potential impact on aneurysm stability. For instance, type 2 endoleaks, which involve retrograde flow from branch vessels, often resolve spontaneously and may not pose an immediate threat. Therefore, monitoring may be sufficient. Typically, intervention will be considered if there is evidence of aneurysm sac expansion or other complications.

Is the primary goal of endovascular aneurysm repair to prevent endoleaks?

No. The main objective of EVAR is to prevent aneurysm rupture by excluding the aneurysm sac from systemic blood circulation. While preventing endoleaks is important, it is not the primary goal of this treatment. Because endoleaks are a known complication of EVAR, their early detection and management is a key component of postoperative care.

Are type 3 endoleaks not a concern because they are so rare?

Type 3 endoleaks, which involve a defect in the stent graft fabric, are not as rare as previously thought. Recent studies show that their incidence is approximately 1.6% in certain stent grafts. These endoleaks are significant because they can lead to aneurysm sac pressurization and expansion, increasing the risk of rupture. Therefore, a type 3 endoleak requires a prompt diagnosis and appropriate treatment.

Can endoleaks be completely prevented with meticulous surgical techniques?

While proper device selection and precise EVAR techniques can reduce the risk of endoleaks, these complications cannot be entirely prevented. Factors such as the patient’s unique anatomy and vessel quality and the natural history of the aneurysm can play a significant role in the development of endoleaks. Regular postoperative surveillance is essential to detect and manage endoleaks effectively.

Does the presence of an endoleak immediately after EVAR signal a poor long-term outcome?

Not necessarily. While identifying blood flow in the aneurysm sac post-EVAR is important, the usefulness of the endoleak as a primary indicator of procedural success or failure is unclear. The long-term outcome can vary depending on multiple factors, including the type of endoleak, the aneurysm characteristics and the patient’s health.

Benefit From World-Class Care at TGH

TGH offers comprehensive care for patients with endoleaks, a common complication of endovascular aneurysm repair. Our nationally recognized Heart and Vascular Institute is equipped with advanced technology and staffed by a multidisciplinary team of specialists who are experienced in both traditional open and minimally invasive endovascular approaches to treat aortic diseases, including endoleaks.

TGH is distinguished as the only hospital in Florida with an FDA-approved, physician-sponsored Investigational Device Exemption (IDE) to treat complex aortic aneurysms, underscoring our commitment to providing cutting-edge treatments. Additionally, our collaboration with the University of South Florida (USF) Health Morsani College of Medicine ensures that our patients have access to board-certified vascular surgeons who utilize the latest medical therapies for managing a wide range of heart conditions.

With state-of-the-art facilities, specialized expertise and innovative treatment options, TGH’s Heart and Vascular Institute is a leading choice for patients seeking care for endoleaks. To request a consultation with a specialist on our team, please contact us at (813) 844-3900.