Keywords
thoracic endovascular aortic repair - extra-anatomical aorto-aortic bypass - aortic
bypass graft - complications
Introduction
Type B aortic dissection (TBAD) is a potentially life-threatening disease. A complicated
TBAD requires invasive treatment immediately.
Around 10 to 40% of these patients develop complications that require new interventions.[1] Although the replacement of the descending aorta is the technique of choice preferred
in this subgroup, in patients with preexisting conditions (clinical situation, anatomical
problems, comorbidities, etc.) the exclusion of the descending aorta with an extra-anatomic
aorto-aortic bypass grafting (ascending aorta to abdominal aorta) can simplify the
procedure and solve the pathology.
We present two cases with TBAD initially treated by endovascular stent graft who developed
aortic complications that required surgical treatment.
Case Presentation and Surgical Approach
Case 1
A 50-year-old female patient, treated with stent graft for complicated TBAD 6 months
ago, is brought to the emergency room for massive hemoptysis associated with hypovolemic
shock. The computed tomography scan shows enlargement of the aorta's isthmus with
endoleak type I, compression of the left main bronchus, and aortobronchial fistula
([Fig. 1]: Case 1). The ascending aorta appears normal. The patient is in circulatory shock
prior to entering the operating room.
Fig. 1 Case 1: Preoperative CT scan showing proximal endoleak (yellow arrow) and contact
of the aneurysmal sac with airway. Case 2 : Aneurysm of ascending aorta and proximal
endoleak (yellow arrow).
A selective intubation is performed. The intubation is carried out with sternolaparotomy
(Mercedez Benz), cardiopulmonary bypass with double-arterial (right axillary/right
femoral) cannulation (Cannula EOPA TM Arterial Cannulae, Medtronic, United States),
and venous cannula (Edwards Lifesciences, Irvine, CA) in the right atrium. During
deep hypothermia circulatory arrest (DHCA) the dissection is completed, the ascending
aorta is clamped, and cardioplegia infused. Next, the supraceliac aorta is clamped,
and femoral cannula performs the visceral protection. The distal end of the descending
aorta is closed, and it is excluded from the circulation, and the ascending aorta-supraceliac
aorta bypass is constructed (end-to-end) with a Dacron graft # 20 (Hemagard, Maquet,
Germany) ([Fig. 2A]).
Fig. 2 (A) Extra anatomical aorto-aortic bypass from ascending aorta (Ao) to supraceliac aorta
with dacron graft (pr) through the diaphragm (d). (B) Stent removed. (C) Thoracic aortic resection and removal of clots.
At 18°C the innominate artery is clamped, preserving axillary and visceral perfusion.
The aortic arch is opened, and the stent graft is extracted ([Fig. 2B]). The distal arch is closed with a Dacron patch. The proximal anastomosis of the
ascending aorta-abdominal aorta (end-to-side) is completed. Then, the airway is decompressed
by removing clots from the descending aorta ([Fig. 2C]) confirmed by bronchoscopy. Several days after surgery, the patient evolves with
sepsis, abscess of the residual aortic sac, which is communicated with the airway,
requiring left pneumonectomy. The patient was discharged after 60 days of hospitalization.
No neurological complication was observed.
Case 2
A 65-year-old male patient, obese, hypertensive, chronic obstructive pulmonary disease
(COPD), diabetes, underwent endovascular treatment for type B dissection. Patient
evolves with sac enlargement and type 1 endoleak ([Fig. 1]: Case 2). The patient presents the history of two endovascular treatment with previous
unsuccessful stent placement. The proximal descending aorta measured 80 × 90 mm, ascending
aorta 50 mm, abdominal aorta 33 mm, and it presented a flap dissection. It was decided
to avoid a thoracotomy based on risk factors for adverse events related to the incision
in the patient (obesity and COPD).
The approach was similar to that described earlier in terms of cannulation and surgery
strategy. In this case, due to the necessity to replace ascending aorta and aortic
arch, we infuse cardioplegia after clamp, and the proximal anastomosis was drawn in
sinotubular union with a Dacron graft # 28 (Hemagard). At 18°C, the supraceliac aorta
is clamped. Visceral perfusion is maintained by the femoral cannula, and the brain
by the brachiocephalic artery. Ascending aorta and arch were replaced, and after that,
the distal anastomosis of the Dacron graft previously sutured to the aortic root anastomosed
to an island containing brachiocephalic artery and left carotid artery. The left subclavian
artery is reinserted separately with a Dacron graft # 8 (Intergard, Maquet).
During rewarming, the proximal and distal ends of the descending aorta are closed.
The supraceliac aorta is perfused by an extra-anatomical aorto-aortic bypass (end-to-end)
with a Dacron graft # 26 (Hemagard). The patient evolves without intercurrences, and
is discharged after 7 days of hospitalization.
No paraplegia was observed in any of the cases.
Discussion
The incidence of complications requiring surgical solve post-thoracic endovascular
aortic repair (TEVAR) ranges between 2.2 and 7.2%.[2]
[3] Aortobronchial fistula is a rare complication (<1%) according to the current trial.[4] Treatment should be radical in the lung (lobectomy, pneumonectomy), as well as in
the aorta (stent removal, replacement of the aorta, washing, and removal of mediastinal
clots).[5] In the first case, it was decided an extra-anatomical resolution with a patient
in shock, with the aim of a quick defunctionalizing of the descending aorta, decompressing
the airway, and waiting for the resolution of the bronchial fistula ([Fig. 3]).
Fig. 3 Case 1: Postoperative 3D recostruction. Extra anatomical aorto-aortic bypass with
dacron graft (yellow arrow). Case 2: Postoperative 3D recostruction showing (a) aorto-aortic bypass, (b) brachiocephalic artery, (c) left subclavian bypass, (d) left carotid artery.
Having used double-arterial cannulation (axillary and femoral) allowed us to keep
visceral and cerebral circulation throughout the procedure. The use of DHCA is not
mandatory; however, it was done to favor both the spinal and cerebral protection.
We consider that this resolution may be useful in selected patients and special situations.[6]
Although the endovascular treatment is the first choice in TBAD complicated, this
is not exempt from late complications. Endovascular route can not always solve such
complications.
Conclusion
Surgery is an excellent choice for complex complications after TEVAR with previous
failed attempts of endovascular resolution, representing a definitive solution to
endoleak, preventing the recurrence of the same.
