Acute non-A non-B aortic dissection: incidence, treatment and outcome.

OBJECTIVES: Our aim was to report outcome of patients with acute non-A non-B aortic dissection involving the aortic arch but not the ascending aorta.

METHODS: Dissection extension and entry location were analysed in patients with acute aortic dissection admitted between 2001 and 2016 at a tertiary centre. Non-A non-B dissection was classified as descending-entry type with entry distal to the left subclavian artery and dissection extending into the aortic arch, and arch-entry type with entry between the innominate and left subclavian arteries. We compared these 2 groups' clinical presentation, treatment and outcome.

RESULTS: Among 396 acute aortic dissection patients, 43 (median age 60 ± 12 years, 81% males) had non-A non-B dissection (descending-entry n = 21, arch-entry n = 22). The overwhelming majority of aortic segments were not dilated in all these patients. The 2 groups' cardiovascular risk profiles did not differ. Emergency open or endovascular aortic repair were necessary due to malperfusion or aortic rupture in 29% descending-entry and 36% arch-entry (in-hospital mortality was 1/6 and 3/8, respectively). Aortic repair within 2 weeks due to new organ malperfusion, rapid aortic growth, aortic rupture or persisting pain was performed in 43% descending-entry and 36% arch-entry patients (0% in-hospital mortality). All others (except for 1 diagnosed in 2014) required aortic repair for aneurysm at follow-up.

CONCLUSIONS: Acute non-A non-B aortic dissection frequently requires emergency aortic repair due to organ malperfusion or aortic rupture. Most descending-entry and arch-entry non-A non-B dissection patients undergo aortic repair within 2 weeks after dissection onset.