IS THERE ANY PLACE FOR THE ENDOVASCULAR TREATMENT OF THE ACUTE TYPE A DISSECTION?

Acute aortic dissection is a catastrophic condition, which arises from a tear in the intima of the aorta, resulting in separation between the intimal and medial layers of the aortic wall and subsequent entry of blood flow within the media. Extension of the dissection may be antegrade, retrograde or bidirectional.

The pressurization of the false lumen of the aorta can lead to coronary, brachiocephalic or branch vessel malperfusion, as well as aortic valve insufficiency, or aortic rupture.

 The entry tear in aortic dissection is located in the ascending aorta in two third of cases and more than half of these are within the first 2 cm of the ascending aorta 1 .

Open repair with replacement of the diseased aorta remains standard therapy for the majority of patients. The primary goals of surgical therapy are to resect the origin of the intimal tear and to reapproximate the intima to the media and adventitia in order to obliterate the false lumen.

Despite continuous improvements in imaging techniques, medical therapy, and surgical management, the incidence of early death among patients undergoing acute type A aortic dissection (TAAD) repair is 17% to 31% 2,3.

In addition, mortality rates for specific subpopulations have been reported to be as high as 75% and up to 8% of all patients with an acute Type A aortic dissection are deemed inoperable even in high volume centres.

A majority of these patients (66%) with acute type A dissection deemed inoperable died within 30 days, and after 4 years almost all had passed away. Conservative treatment in these patients was obviously ineffective. The endovascular approach to acute aortic dissection type A is an attractive topic often discussed at scientific meetings, the subject of many case reports and addressed in papers on the limits of endovascular aortic repair.

It is, however, still not considered in the literature discussing standard treatment options. Thoracic endovascular repair (TEVAR) may be considered as an alternative in high-risk or inoperable patients. The goals of TEVAR are similar: to cover the origin of the intimal tear in order to prevent aortic rupture as well as to reduce pressure and promote thrombosis of the false lumen.

TEVAR is contraindicated if there is severe aortic valve regurgitation, if the dissection involves the aortic root or if the patient has a connective tissue disorder except as a temporizing solution until definitive surgery can be performed.