Keywords
heart valve - transapical - percutaneous - endovascular aortic repair/stents - hybrid
aortic repair - aortic disease
Introduction
Open surgery is considered the standard of care for patients with ascending aortic
pathology. However, there are several reports on using thoracic endovascular aortic
repair (TEVAR) in high-risk patients who may not tolerate open surgical intervention.[1]
[2]
[3]
[4]
[5]
[6] Hybrid aortic repair is advocated whenever an open surgical repair is high risk
or contraindicated, and TEVAR is not feasible due to anatomical complexity. The coexistence
of severe aortic stenosis with the complex proximal aortic disease requires extensive
discussion and appropriate planning by the heart team members.
In this case, we report a hybrid total thoracic aortic repair and valve-in-valve (V-I-V)
transcatheter aortic valve replacement (TAVR) in a high-risk patient with complicated
chronic type A dissection and severe prosthetic aortic stenosis.
Case Report
This is a case of a 74-year-old female patient who presented with shortness of breath
on exertion and upper back pain. Two years prior to her current presentation, she
had acute type A aortic dissection for which she underwent the Bentall procedure with
a bioprosthetic valve (Mitroflow size 23) in another institution. Computerized tomography
(CT) done upon presentation showed a remnant dissected ascending aorta with a dissection
flap extending down to the aortic bifurcation. It also showed a large aneurysm starting
at the base of the left subclavian artery and extending to mid descending thoracic
aorta measuring 7.8 cm at maximal diameter ([Fig. 1]). There was severe calcification at the aortoiliac bifurcation with severe tortuosity
in the iliac and femoral vessels. Echocardiogram showed severe aortic stenosis with
a mean gradient of 55 mm Hg. Based on the clinical presentation and the imaging findings,
the ideal approach to manage this patient would be a redo sternotomy, redo Bentall
procedure, aortic arch replacement, and elephant trunk under deep hypothermic circulatory
arrest followed by a second procedure for elephant trunk completion. Given the patient
age and comorbidities, we entertained a hybrid approach including redo sternotomy
with aortic arch debranching from the ascending aortic graft followed by TEVAR of
the ascending aorta, aortic arch and descending thoracic aorta, and finally direct
trans-aortic V-I-V TAVR.
Fig. 1 CT Aortogram of the chest demonstrating the dissected thoracic aorta with a large
aneurysmal cavity of the distal arch and proximal descending aorta. (A) Axial view. (B) Sagittal view.
Initially, the patient underwent redo sternotomy and cardiopulmonary bypass was established
using right axillary arterial cannulation and direct right atrial venous cannulation.
The dissected native aorta was clamped 2 cm below the innominate artery, and a trifurcated
graft was sutured to the right side of the Bentall graft 2 cm above the origin of
the implanted right coronary artery. The distal anastomoses of the debranching limbs
to innominate and left common carotid arteries were performed off bypass. Finally,
the origin of both debranched vessels were ligated. The third limb of the trifurcated
graft was tied and left in the mediastinum as an access for the future planned TAVR
procedure ([Fig. 2]).
Fig. 2 Operative image showing the debranching graft with two limbs bypassing the innominate
artery and left common carotid artery (black arrows) and the third limb reserved for
future direct transaortic TAVR (blue arrow).
One week later, the patient underwent TEVAR through a cut down on the right femoral
artery. Three overlapping endovascular stent grafts size 32 ×142 mm (Cook Zenith TX2
endovascular graft) were deployed starting just above the level of the debranching
graft and covering the whole thoracic aorta down to 4 cm above the origin of the celiac
artery ([Fig. 3A]). Postoperative CT scan showed complete thrombosis of the false lumen in the thoracic
aorta proximal to the distal landing zone ([Fig. 3B]).
Fig. 3 Postdeployment of three overlapping TEVAR grafts. (A) 3D reconstruction of the thoracic aorta post TEVAR. (B) Coronal reconstruction of the thoracic aorta showing complete thrombosis of the
false lumen in the thoracic aorta proximal to the distal landing zone.
Four days later, the patient underwent resternotomy and the third limb of the trifurcated
graft was retrieved and was used as an access for direct aortic V-I-V TAVR. Size 26
Edward's Sapien 3 valve was deployed inside the previous valve over a Safari wire
([Fig. 4]) without complications and there was no evidence of any paravalvular leak. The patient
was later discharged home in stable condition after 3 weeks in the hospital.
Fig. 4 Fluoroscopic image post V-I-V TAVR deployment showing the different angles of the
thoracic aorta (black arrows).
Discussion
We presented here a very complicated case with complex anatomy in a high-risk patient
for which the hybrid approach represents the safest approach. To our knowledge, this
is the first reported case of zone zero TEVAR followed by V-I-V TAVR in the setting
of chronic type A dissection.
The first debranching procedure was performed on-pump because the Bentall graft was
short measuring only 4 cm above the site of the implanted right coronary artery that
made the application of the side biting clamp very difficult. We elected not to bypass
the left subclavian artery because it was deep in the left thoracic cavity and it
was adherent to the large thoracic aneurysm of the distal arch.
For the second procedure, there were several challenges that required appropriate
planning and adequate experience. The first challenge was the chronically dissected
aorta with multiple fenestrations that necessitated the use of intravascular ultrasound
to confirm that the TEVAR introducing system was traversing the true lumen through
its whole course. The second challenge was the extensive calcification and tortuosity
in the femoral and iliac vessels that required careful insertion and monitoring of
the stent grafts during insertion. The third challenge was the aortic configuration
that consisted of three angles through its thoracic course as a result of the aortic
enlargement and elongation ([Fig. 4]). These three angles caused a significant resistance and loss of system energy during
the insertion of the three stent grafts. One of the options that we discussed for
this patient was the use of a custom-made double or triple-branched device for the
aortic arch. However, this option, although not available in our country, was not
technically feasible given the large size of the aortic arch false lumen, which in
cases of chronic dissection could complicate the deployment of the branched stent
and the alignment of its branches in the corresponding arch vessels. We thought that
this option will carry a higher risk of technical failure and type 2 and 3 endo-leaks.
In our experience, the thrombosis of the false lumen in the thoracic aorta in chronic
dissection cases is associated with stabilization of the size of the thoracic aneurysm
and possibly regression in most of the cases. Follow-up with a CT aortogram is very
important every 6 months to detect any future progression, usually in the abdominal
nonstented aorta. If the abdominal aorta progresses in the future, then our preferred
approach would be an open surgical repair of the abdominal aorta with direct anastomosis
to the lower part of the stent. Alternatively, in very high-risk patients, we may
elect to perform visceral and renal artery bypasses from the femoral or iliac arteries
and then perform endovascular aortic repair of the whole abdominal aorta.
The main challenge for the third procedure was the access site choice for TAVR. We
thought that the safest option would be direct aortic access through the side graft
that was planned during the initial stages of the intervention. We did not use the
self-expanding transcatheter heart valve (THV) (Evolut R/PRO) because of its tall
stent frame that could disrupt the debranching graft anastomosis.
Conclusion
Hybrid thoracic aortic repair is safe in high-risk patients with highly complex aortic
anatomy. Careful discussion and planning by heart team members is crucial for the
success of these procedures.
