What is TEVAR?
TEVAR is a minimally invasive approach to repair thoracic aortic aneurysms. The technique and devices were developed to treat patients who could not tolerate open surgical repair because they have too many medical problems.
How does one perform TEVAR and why is the technique considered minimally invasive?
An endovascular stent is used to repair the thoracic aortic aneurysm. A stent is a synthetic tube that provides a new lining to the aorta and diverts blood away from the aneurysm. The stent is placed through the femoral artery and delivered into the aorta. The patient may only have one small incision in the groin region. This technique avoids a large chest incision.
How do I know if I am high-risk for open surgery?
The common medical problems and physiological variables that can increase the risk of open surgical repair are severe emphysema, heart failure, severe coronary artery disease, dialysis (kidney failure), malnourished patients, and advanced age(>80 years old). Although, every patient needs to be evaluated carefully and thoroughly prior to any type of intervention and a comprehensive disscussion should be undertaken to consider the the pros and cons of each intervention.
Who should I discuss my options for repair with?
You should discuss your overall health with your primary care physician, cardiologist and surgeon. In general, your cardiologist and primary care physician will be the best judge of your health.
What is an endovascular stent?
A stent is a synethetic tube made of heavily woven fabric with some form of metallic framework. The stent is introduced into the femoral artery in a collapsed form and then opened once it is positioned within the aortic aneurysm ( see video below).
How does an endovascular stent fix the thoracic aortic aneurysm?
The stent provides a new lining to the aorta diverting blood away from the aortic aneurysm. The stent anchors itself on “normal” areas of the aorta above and below the site of the aortic aneurysm. The length of “normal ” aorta in the anchoring zone is important to achieve a “good” and durable repair.
What are other considerations prior to performing TEVAR?
After a thorough discussion with your surgeon that this is the appropriate option for you and not only the “less invasive method”, there are many variables that need to be considered. The anchoring zone should be free of dissection, clots, atherosclerosis, and early signs of an aortic aneurysm (large aortic diameter). The femoral and iliac arteries ( see anatomy page) should not be very tortuous, calcified (hardened) or have severe atherosclerosis. The diameter of the iliac and femoral arteries need to be of a certain diameter for the delivery of the endovascular stent. In certain cases, you may need an adjunct open procedure to prepare you for the endocascular stent such as a carotid-to-subclavian artery bypass or aortic arch replacement. In order to determine if you are a candidate for TEVAR, you will need to undergo a full body CT scan or MRA to visualize the entire aorta and femoral arteries.
Do high-risk patients have open surgery?
If TEVAR can not be performed because of anatomical reasons such as too much atherosclerosis, calcium build-up, or tortuous aorta or femoral arteries. If there is no local experience with TEVAR. In a case of an emergency such as in aortic rupture. If the TEVAR repair will not result in a durable result. In addition, in certain situations an infected aortic aneurysm is not amendable to TEVAR.
Who are good candidates for TEVAR?
- saccular aneurysm isolated to the descending thoracic aorta (see anatomy page)
- aneurysm of the distal aorta arch (may need open surgery in addition to TEVAR)
- isolated aortic dissection to the descending thoracic aorta
- patients with Type B aortic dissection with rupture and malperfusion (blood is not being delivered to certain organs)
- elderly patients with rupture of a descending thoracic aortic aneurysm or isolated penetrating ulcer.
What are anatomical reasons patients are not appropriate for TEVAR?
- Arteries in the pelvis (iliac arteries) are too curvy (tortuous) or heavily calcified (too much calcium build up)
- Abdominal or thoracic aorta is too curvy
- Too much calcium or atherosclerosis (cholesterol build-up) in the aorta
- Aortic dissection is present in the area of anchoring the stent
- Branches of the aorta will be blocked with the stent (although certain techniques can be used to avoid this problem but not always successful or appropriate)
What are complications of TEVAR?
- Endoleaks-blood is getting into the aneurysm sac around the stent, no longer a completely repaired aneurysm, needs very careful monitoring with CT scans or MRI every 3 to 6 months to check if aneurysm is expanding. Certain endloeaks are less worrisome however you should discuss this with your aortic specialist. Some patients need open repair if an endoleak can not be repaired with endovascular techniques (new stent, coils, etc.). Endoleaks have been associated with poor long-term survival.
- Migration-less of a problem with newer stents but again needs to looked for in your surveillance CT scans after the stent is implanted.
- Fracture: less of a problem with newer designs.
- Collapse: partial or complete, can occur early or late. This probelm will need repair usually with a new stent. This can lead to complete blockage of the aorta (bad!) or endoleak. CT scan and plain x-ray can pick up this complication.
- Paraplegia
- Stroke
Check out this video on TEVAR:
What do you need to be considered for TEVAR?
- full body CT angiogram or MRA from the neck to the pelvis (need to know the extent of the aneurysm and the arteries needed to deliver the stent.
- general medical information
- cardiac work-up