Complex Endovascular Repair of Aortic Aneurysms

This article aims to make patients aware of complex aneurysms and the minimal invasive repair (Endovascular Repair) of such aneurysms.

What are Different Complex Aortic Aneurysms?

Complex aortic aneurysms involve ballooning of the aortic artery involving vessels to other organs such as kidneys, bowel or brain. In the case of complex aneurysms, neighbouring branching vessels or thoracic aorta major branches may become a part of the aneurysm. Therefore, the aneurysm treatment gets complicated and requires special procedures like complex endovascular repair.

Here are three complex aortic aneurysms for which you will need open, complex endovascular or hybrid surgical repair.

Juxtarenal Aortic Aneurysm

Unfortunately, not every case of abdominal aortic aneurysm is suitable for standard endovascular repair. Standard EVAR requires about 1-2 cm of the normal aorta between the branching point of renal arteries and the aneurysm.

The aorta that lies between the aneurysm and renal artery origin is the neck of the aneurysm. In cases with a neck shorter than 1cm, the abdominal aortic aneurysm becomes the juxta-renal aortic aneurysm because of the involvement of renal (kidney) arteries.

In the case of juxta aneurysms, standard EVAR increases the likelihood of postoperative complications, especially endoleaks. Therefore, surgeons prefer open or complex endovascular repair with unique design stents to accommodate the renal arteries.

Thoraco-abdominal Aortic Aneurysm

There are rare possibilities that aortic aneurysms may involve part of the thoracic aorta and abdominal aorta together with the involvement of renal and mesenteric (intestinal) arteries. Such complex aortic aneurysms are known as thoracoabdominal aortic aneurysms. Like juxta aneurysms, these aneurysms can be treated with endovascular techniques that require a modified or complex endovascular stent. Such stents have fenestrations or branches to accommodate the branching arteries.

Based on its location, the thoracoabdominal aortic aneurysm may involve one of the following types.

Types I: It involves most of the thoracic aorta while only the upper part of the abdominal aorta.
Type II: It involves the majority of the thoracic and abdominal aorta.
Type III: It’s the opposite of type I, involving a significant portion of the abdominal aorta with only the lower part of the thoracic aorta.
Type IV: It involves the abdominal aorta with its junction with the thoracic aorta.

Aortic arch aneurysm

The aortic arch comprises the part of the aorta in your upper chest. This part of the aorta supplies blood vessels to the head, neck, and upper limb tissues.

What are the Different Types of Stents for Complex Endovascular Aortic Aneurysm Repair?

A complex endovascular repair can differ from one patient to another depending on the anatomy of the aneurysm, its closeness to major arterial branches, and the type of graft used. Most of these grafts are custom made based on the patient’s anatomy, and it typically takes 4-8 weeks to create these fenestrated or branched stent grafts.

Fenestrated Stent Grafts

Fenestrated stent grafts are used for endovascular treatment of juxta-renal aortic aneurysms. These grafts have holes (fenestrations) in the stent-graft fabric. Holes are according to the openings of renal and mesenteric arteries. Therefore, extra sents through this fenestration maintain the flow to the side branches. The precise placement of the fenestrations within the graft is critical to success. The surgeon accomplishes this through careful preoperative imaging, planning, and 3D reconstructions.

Branched Stent Grafts

In contrast to having fenestrations, branched stent grafts consist of small branches fixed to the main aortic stent. The branches with extra stents help maintain circulation to the branching arteries without leaking blood outside the stent. Such grafts are preferable for endovascular repair of thoracoabdominal aortic aneurysms or even the aneurysm of the aortic arch. However, such grafts have been introduced over the last few years. Therefore, the literature needs more clinical studies to assess long-term effectiveness.

Fenestrated Endovascular Repair

In medically fit patients, open surgical repair for juxta-renal aortic aneurysms is still the best therapy option for long term outcomes. However, fenestrated endovascular repair remains the most common method in juxta-renal abdominal aortic aneurysm endovascular procedures. It’s due to the fenestrated repair’s several benefits.

The following are some of the most significant advantages:

Minimal risk of endoleak compares to the usage of stander EVAR in short neck anatomy.
Short-term hospital stays for only 2-3 days
Smaller incision
Quick healing and recovery

What Happens Before the Operation?

Before the operation, your vascular surgeon will do a thorough assessment to assess your health status. In addition, he will tell you every minor detail about the procedure and risks. If you have any concerns about the process, feel free to ask any questions in the pre-op assessment meeting.

Moreover, your anesthesiologist will also take your complete medical history relating to your disease or medications. He will also perform a physical examination and order some tests to see whether you are fit for the procedure or not.

The most important part of the pre-op assessment is imaging the aortic aneurysm. Imaging allows the vascular surgeon to select the graft suitable for the patient. In most cases, planning, imaging, and multidisciplinary meeting discussion are necessary to make the surgery effective.

What Does the Surgery Involve?

Surgical repair through fenestrated endovascular repair involves the following steps.

The surgeon can perform the surgery under local or general anaesthesia. Depends upon personal fitness and the complexity of the surgery. In both cases, you would not feel any pain.
Using X-ray imaging, your surgeon will insert the catheter into the aorta through your primary groin artery.
He will then open the fenestrated graft at the required position.
He will introduce more small stents through the fenestrations to the major affected arteries, such as the main arteries to your kidney and bowel. This will connect the side branched arteries to the fenestrations in the main stent.
He will inject a special dye to produce pictures of blood vessels to check the circulation to all major arteries and the position of the stent.
He will remove the instruments and close the small opening in your groin arteries.
He will then stitch the wound and apply sterile dressings over the groin.

Usually, you will be hospitalised for 2-3 days following surgery for monitoring and early detection of any complications.

What are the Complications Associated with the Surgery?

However, complex endovascular repair is a minimally invasive procedure, but some risk of complication is present. Some of the complications that can occur during or after the surgery include:

Endoleak: leakage of blood outside the stent to the aneurysm
Bleeding
Kidney failure
Blockage of one of your stents or major arteries
Wound leakage or infection
Heart attack and arrhythmias that can lead to death
A clot in the vein of the leg DVT that may result in clot migration to the lungs
Graft infection
Paraplegia due to a spinal cord ischemia

Each patient’s risks vary depending on the extent of the aneurysm and the patient’s fitness for surgery. Your vascular surgeon will explain your rupture risk without intervention and your treatment options, including open surgical and complex endovascular repair with all the intervention’s risks. Then, you will make the final decision about whether or not to have the operation.