Ascending aortitis: a clinicopathological study of 21 cases in a series of 300 aortic repairs.

There are few single-institution clinicopathological series of aortitis. In this study, all ascending aneurysms were prospectively evaluated pathologically with ≥6 aortic sections over a 6-year period.Of 300 ascending aortic resections, there were 21 cases of aortitis (7%), in 11 women and 10 men (mean 67, range 41-88 years). There were 19 patients with aneurysms, and two patients with sclerosing periaortitis, clinically suspected to have intramural haematoma. Of the 19 patients with aneurysms (11 women), two had prior temporal arteritis, one ankylosing spondylitis, one IgA nephropathy, one undifferentiated autoimmune disease, one Lyme disease, and one fibromyalgia. In only two patients was aortitis suspected before surgery as the cause of aneurysm. Four patients developed distal aortic aneurysm requiring repeat surgery. Valve replacement or repair was necessary in nine patients, and two patients died after surgery. There were no significant differences between patients with and without autoimmune disease. The histological features were necrotising aortitis in 18 of 19 patients with aneurysmal aortitis, and there was one case of non-necrotising aortitis. One valve showed autoimmune valvulitis, congenitally bicuspid associated with ankylosing spondylitis. Necrotising aortitis was classified as acute (n = 5), healing (n = 9), and healed (n = 4). Acute necrotising aortitis was associated with need for valve replacement (p = 0.01) and younger age (p = 0.01). The healed phase had subtle histological features, sparse medial inflammation, marked medial attenuation, and chronic adventitial inflammation. Two patients with periaortitis demonstrated marked fibroinflammatory thickening of the adventitia with histological features typical of IgG4-related disease; neither had systemic symptoms. Ascending aortitis is histologically diverse, most frequently of the medial necrotising type, and is usually not suspected pre-operatively. Awareness of the histological spectrum is necessary for pathological diagnosis.