Endovascular Repair of the Ascending Aorta for Acute Type A Aortic Dissection

Derek R. Serna-Gallegos, MD
Ibrahim Sultan, MD, FACS

Endovascular repair of the aorta has become an established treatment for acute aortic dissections, aneurysms, and intramural hematomas of the descending thoracic and abdominal aorta. In contrast, the ascending aorta has previously not been considered amenable to endovascular repair due to anatomic and physiologic constraints. The ascending aorta is more dynamic than the descending thoracic aorta and undergoes vast conformational changes with each heartbeat. In contrast, the stent-grafts used for endovascular repair are relatively static and are at risk for being dislodged due to the very dynamic environment of the ascending aorta. Additionally, the curvature of the ascending aorta, location of the origin of the brachiocephalic arteries, sinus segment effacement, coronary artery origins are all important considerations when planning an endovascular strategy for the ascending aorta. At the UPMC Center for Thoracic Aortic Disease in the UPMC Heart and Vascular Institute, we routinely treat the descending thoracic aorta in an endovascular fashion. However, careful patient selection is critical when planning for endovascular treatment of the ascending aorta.^1,2 

Acute Type A aortic dissection (TAAD) is typically fatal when not treated expeditiously. The gold standard for treatment continues to be open surgery for these patients. However, if the patient is too frail or otherwise at prohibitive risk for surgery, medical management is employed to maintain blood pressure control and to reduce the risk of rupture. Endovascular repair should only be considered when the patient is a poor candidate for surgery due to comorbidities and when the anatomy of the ascending aorta and the dissection is amenable to thoracic endovascular aortic repair (TEVAR). 

Due to the considerable challenges present in the ascending aorta, the pool of patients for whom TEVAR is considered appropriate is small. The lesion must be anatomically amenable to TEVAR. There must be proximal and distal landing zones of at least 1 cm that do not compromise the coronary ostia or brachieocephalic vessels, and the ascending aorta must accommodate a stent-graft within the treatment sizing range.³ Additionally, coronary revascularization procedures can pose an important limitation for TEVAR in the ascending aorta because previous coronary bypass grafts may be occluded with stent-graft coverage in the ascending aorta, and the presence of a stent may prevent future revascularization.⁴

Most recently, we treated a 67-year-old woman with multiple comorbidities, including chronic obstructive pulmonary disease (COPD) who was oxygen dependent and chronic kidney disease on dialysis. She was initially admitted to an outside hospital because of exacerbation of her COPD, which caused pneumonia and respiratory failure necessitating a tracheostomy. While hospitalized, she had a stroke. Imaging to evaluate the stroke revealed a type A aortic dissection. The patient was subsequently transferred to our institution for further management. Further evaluation of this patient’s imaging studies and an echocardiogram allowed us to consider her for endovascular treatment of her TAAD.

A systematic review of reports of TEVAR of the ascending aorta published between 1995 to 2017 found 46 publications detailing primary endovascular repair of the ascending aorta using stent grafts in a total of 118 patients.⁵

Most of the publications were case reports or series with 10 or fewer patients, although one series reported outcomes for 15 patients, and the largest series contained 21 patients. Half of the 118 patients (50%) had a type A aortic dissection, the same diagnosis as our patient. Patients were also treated for aortic pseudoaneurysm (30%), aortic aneurysm (5%), penetrating ulcer as a result of atherosclerosis (4%), and aortic rupture (2%). The most common approaches were transfemoral and transapical. The delivery system for the stent used for repair dictated the approach in some patients.

Endoleaks, a complication unique to endovascular stenting that occurs when blood leaks around the outside of the stent, occurred in 18% of the patients. This is significantly higher than the incidence of endoleak reported for TEVAR of the thoracic descending aorta (<10%) and is likely a limitation of the current technology. Other complications included postoperative myocardial infarction (3%), cerebrovascular complications (3%), and stent migration (2%). Respiratory complications have also been reported after TEVAR in the ascending aorta.

Of the 118 endovascular procedures, four (3.4%) required conversion to open surgery, and 11 required surgical reintervention (9%). In the largest series of TEVAR of the ascending aorta published to date, 9% of procedures required conversion to open surgery, and 32% of survivors (6 of 19) required surgical re-intervention.6 It is worth noting, however, that two of these re-interventions were planned prior to the initial TEVAR. In the systematic review, all-cause mortality after TEVAR of the ascending aorta was 15%, and aorta-related mortality was 5%. Two-thirds of the patients (67%) remained free of aorta-related complications during follow up, and 60.2% did not experience any complications during follow up. 

Our patient was treated successfully with off label overlapping endografts in the ascending aorta that allowed for coverage of the primary tear of the patients TAAD. Her postoperative course was unremarkable and she was discharged successfully. Follow up revealed a well sealed endograft with aortic remodeling.⁵ Careful patient selection with favorable anatomic characteristics is critical in ensuring successful outcome in patients with endovascular treatment of TAAD.

To learn more about the UPMC Heart and Vascular Institute or to refer a patient, call 412-770-4949. 

References

1. Sultan I, Dufendach K, Kilic A et al. Bare Metal Stent Use in Type B Aortic Dissection May Offer Positive Remodeling for the Distal Aorta. Ann Thorac Surg 2018;106:1364-1370.

2. Brown JA, Arnaoutakis GJ, Kilic A, Gleason TG, Aranda-Michel E, Sultan I. Medical and surgical management of acute type B aortic intramural hematoma. J Card Surg 2020.

3. Plichta RP, Hughes GC. Thoracic endovascular aortic repair for the ascending aorta: experience and pitfalls. J Vis Surg 2018;4:92.

4. Klonaris C, Georgopoulos S, Katsargyris A. Endovascular treatment of the ascending aorta: new frontiers for thoracic endovascular aneurysm repair? J Thorac Dis 2016;8:1901-3.

5. Muetterties CE, Menon R, Wheatley GH, 3rd. A systematic review of primary endovascular repair of the ascending aorta. J Vasc Surg 2018;67:332-342.

6. Roselli EE, Idrees J, Greenberg RK, Johnston DR, Lytle BW. Endovascular stent grafting for ascending aorta repair in high-risk patients. J Thorac Cardiovasc Surg 2015;149:144-51. Derek R.